Creating Art by 3D Pen - Juniper Publishers

 

Fashion Technology & Textile Engineering - Juniper Publishers

Abstract

3D printing technology is a new rapid prototyping technology, but 3D pen is a pen with 3D printing function, it’s extrudes heated or warm molten plastic from the pen’s nozzle. You don’t need any software, there are no files to transfer. whatever you imagine, you can draw. It goes from your brain, to your hand. It can cultivate students’ innovative thinking and problem-solving ability in maker education. Despite the many advantages of 3D pens in artistic creation and education, the popularity of 3D pens is so low that many people do not even know the technology or how to use it. When entering “3D pen” or “application of 3D pen” for paper retrieval, the relevant literature can hardly be found. This article is aimed at introducing

a) How 3D pen works?

b) Examples drawn by 3D pen.

c) Variety of materials and color choices.

d) Types of 3D pens in the market and

e) Future possibilities.

Keywords: 3D pen; Application of 3D printing pen; 3D printing; Maker education; Childhood education; Innovative thinking; Art; DIY; Three-dimensional painting; Cultural transmission

Review

For millennia, people around the world are enticed with beautiful, enticing and intriguing drawings, watercolor paintings and oil paintings drawn on different media. Imagine the impressions on people if they are three dimensional instead of mere two dimensional! With the emergence of three-dimensional printing pen or 3D pen, it is now feasible to draw a variety of three-dimensional patterns in the air, like a magic pen. This article is aimed at introducing

a) How 3D pen works?

b) Examples drawn by 3D pen.

c) Variety of materials and color choices.

d) Types of 3D pens in the market and

e) Future possibilities.

History and Introduction

The following schematic, Figure 1 outlines timeline of major technological/scientific milestones in western art over thousands of years, from pre-classical art to classical art, medieval art, European Renaissance art, baroque and rococo art, 19th century western art, to western modernist art. Chinese art has a long history. Unlike Europe, where art styles are always changing, Chinese art has maintained a surprising continuity over the centuries. The works of the Ming dynasty can also see the influence of the tang dynasty. A painting from the Qing dynasty is very similar to one from the song dynasty. One reason is China’s reverence for tradition. Since the 16th century, Chinese arts and crafts, especially porcelain, were exported to Europe in large quantities, which also had an impact on European art. After the republic of China, traditional Chinese art developed with the rapid changes of the times. Chinese painters began to study in the west and have direct contact with European paintings, such as Xu Beihong and others. The establishment of new painting school also promotes the westernization of Chinese painting [1]. The evolution of Indian art style is not only governed by the discipline of formal beauty, but also related to the evolution of Indian religion and philosophy. The ancient art scene of India: bright colors, colorful and exaggerated shapes, and the belief in the afterlife and the past. While highlighting the strong national characteristics, it has also absorbed many artistic factors from Europe and west Asia.

Technological/scientific and art are mutually reinforcing. In the primitive times, only stone chisel technology, red earth as the material, so the rock painting murals; The Neolithic pottery technology, the color pottery above can leave beautiful geometric patterns and animal-shaped patterns. The invention of smelting technology, people cast all kinds of copper and iron, with a metal texture chisel to carve David and other masterpieces. Therefore, smelting technology plays a crucial role in the art of sculpture. The invention of oil paints, as well as the use of perspective, golden section, optics, color, anatomy, black box and other scientific principles and techniques in painting to make painting works closer to the real things. Da Vinci left the Mona Lisa’s eternal smile. With the development of photography technology, nature can be vividly represented. With the gradual improvement of computer technology and functions, painting has developed from the original sketching to computer painting and holographic art works vivid and realistic, combined with sound and electricity and three-dimensional animation [2].

How 3D Pen works?

First, connect the power supply of the 3D pen, the power indicator light will be on, click the feed button, the heating lamp will turn red, the 3D pen will start pre-heating, about 50 seconds of pre-heating completed, the indicator light from red to green (Figure 2). Then press the feed button and add the filament into the feed port [3]. The mechanical device in the pen will send the filament to the heating nozzle to start using. When it does not have any operation within 90 seconds, the system will automatically enter the sleep state, which can effectively avoid wasting energy without any operation for a long time. When the feed button is clicked again, the 3D pen can be awakened. When finished using, press the return button to exit the remaining wire. The 3D pen supports portable power supply, making it safe and convenient. 3D pens from different manufacturers may vary slightly, but the principle is the same (Table 1). Simple 3D pen techniques and skills. Drawing with a 3D pen is like drawing and writing with crayons, pencils and pens you just need to gain control and confidence [4]. It is useful to learn basic techniques and practice on simple 2D templates first. Practice will give you good control. Once you have mastered the art of drawing with a 3D pen, you can draw any three-dimensional pattern or model. The 3D pen allows people to visualize their thoughts and shape your ideas into real shapes.

Examples Drawn by 3D Pen

The 3D pen is like any other tool and skills, it takes a little patience and practice to learn how to use it and gain proficiency. It takes time and practice to draw and model with hot molten plastic.

Design awareness and capability are life skills. To cultivate the creative ability of primary and secondary school students, 3D pens are brought into the classroom in an easy and interesting way, enabling students to cultivate and exercise innovative thinking and creativity through the latest technological tools (Figure 3). For example, in the campus science and technology innovation competition, if the appearance of the entries needs to be modified or some spare parts are needed, then the 3D pen can quickly solve these problems [5]. Schools encourage the exploration of new modes of education. As a new tool used in teaching, 3D pen can turn learning into a process of innovation and creation, cultivate students’ creative thinking, creativity and teamwork ability, and pay attention to the connection between learning and the real world, instead of just the test results of test papers (Figure 4). 3D pens are suitable for people of all ages. Whether they are children, adults or the elderly, anyone can draw with a 3D pen. Fire your imagination, activate your design capability, Enjoy the fun of creating (Figure 5). You can use a 3D pen to make a gift for your family and friends. It will be a special gift because you have made it yourself. You can also use a 3D pen to complete a beautiful painting or make any three-dimensional object to use as an interior decoration. It’s a great way to relieve stress for office workers [6].

The 3D pen can be combined with comprehensive materials to create and solve problems in real life. The 3D pen is a practical tool for DIY enthusiasts. For example, when we want to do a unique small electric fan, need to prepare electronic components for electric fans, motor, blade, batteries, electric wire, switch, and then use 3D pen draw the lid of the electric fan, fixed bracket, draw some beautiful adornment, a unique fan was finished, it can be used as works of art and can be used as a practical article for daily use (Figure 6). It is a good drawing tool for architects and product designers. The covid-19 epidemic of 2020 has emerged and spread so fast that we are all facing a severe test. Due to the outbreak, people have to wear masks to go out and work. However, many masks are produced without considering the need for the tightness and length of the ear strap for a long time. Moreover, the ear strap of the mask needs to be hung on the ear, which can be very painful due to the pressure of the rope on the ear root for a long time. In order to solve the problem of mask wearing, you can use 3D printing pen to design a beautiful and practical “mask adjusting band”. When wearing a mask, the ropes on both sides of the mask can be stuck on the mask adjusting band to free the ears from being squeezed. Wearing masks can also become fashionable (Figure 7). 3D pen painting is another expression form of 21st century painting, which is to inherit, integrate and improve ancient and modern Chinese and foreign things and historical culture. It can make the picture more three-dimensional, colorful, with a very good visual effect, and not easily affected by moisture. 3D pen painting expands the space for artistic creation, allowing artistic works to be presented in various forms (Figures 8 & 9).

Variety of Materials and Color Choices

The consumables (Table 2) used for the 3D pen are ABS, PLA and PCL, monofilament (Ø = 1.75mm). ABS is an engineering material with a melting temperature of 217-237℃, and it has an unpleasant smell during use, so not many people use it now. Polylactide (PLA) is a bio-based and renewable biodegradable material, which is made from materials extracted from renewable grain husk, straw and straw. After being used, it can be completely degraded by nature under specific conditions and eventually generate carbon dioxide and water without polluting the environment. The melting point of PLA is 155-185℃. The molten PLA material is rapidly cooled and solidified in the air after coming out of the pen, forming hard lines, so that the three-dimensional model can be drawn directly in the air, which is very advantageous for making architectural models and three-dimensional structure models. Polycaprolactone (PCL) is a biodegradable material with many excellent characteristics, such as excellent low temperature plasticity, 58-70℃ melting point, good toughness and seawater degradation (Figure 10). The color of materials is very rich, there are already dozens of colors available on the market. And the color and luster of the material that different manufacturer produces can be different, some material color is very pure, some material color can be met light, people can choose different material color according to need. According to the experience of two different colors of materials can also be mixed like a pigment, so that your works will be very rich in color [7].

Types of 3D Pens in the Market

a) The first 3D pens to appear on the filament is the high temperature 3D pen, its operating temperature is around 180- 240℃. When using ABS filament, the working temperature of 3D pen needs to be heated to about 220℃. In such a high temperature condition, users are easy to be scalded by the pen tip, so few people use this kind of high-temperature 3D pen now. When using PLA filament, the working temperature of the pen is around 180℃. Because of the good stereoscopic plastic effect and the relatively affordable price of the material, the sales volume of this 3D pen is very good.

b) It is known that users of 3D pens tend to be younger, especially among primary and secondary school students. In order to consider the safety of pens used by children, the low temperature 3D pen is now on the market, and its printing temperature is around 60℃, which avoids the risk of children being burned by pens in the process of use. It can also be charged with an automatic power supply, making it safer and more convenient. Its corresponding filament is PCL.

c) There are also 3D pens with accumulators on the market, which do not need to be connected to the power supply all the time in the process of use and can work continuously for about two hours. However, its disadvantage is that the pen body is very heavy, which increases the burden of people’s hands when painting.

Future Possibilities

The popularity rate of 3D pens is not very high, and the users are mainly concentrated in the first and second tier cities. Many people in towns and townships have not even seen 3D pens. However, many makers’ centers and schools now offer classes on creating 3D pens, and it is believed that more people will use 3D pens in the next few years. At the same time, the quality of 3D pen will be constantly optimized, the product will be more and more exquisite, and the safety and stability will be better and better. I believe that there will be more people like to use this new painting tool for artistic creation (Figure 11).

Technology and application of 3D pen in the future from 2050 to 2100:

a) In the future, with the development of artificial intelligence, 3D pens are also equipped with intelligent technology. The pen is equipped with a consciousness sensor receiver, which can read the brain signals, read the things and pictures in our brain, and then the 3D pen will draw your thoughts automatically.

b) In the future, 3D pen will be upgraded to 4D printing pen. About “4D printing,” compared to traditional 3D-printed parts, the additional dimension in the time domain allow for the components to undergo dramatic changes in shape when subjected to an external stimulus. stimuli that induce time-dependent behaviors are usually temperature changes or water exposure.

c) 3D pen with AR (Augmented Reality) technology, the virtual information are fused together with the real world of technology, the computer generated text, images, 3D simulation model, music, video and other virtual information, applied to the real world, at the same time to join 3D pen drawing entities part, two kinds of information complement each other, so as to realize the virtual and real world of perfect combination of artistic effect.

d) In a few decades’ time, the 3D pen’s consumables could come from recycled plastic materials that have been processed into biodegradable, environmentally friendly materials. The consumables of 3D pen can also come directly from the nature, such as drawing a river, people directly use water as raw material to print in the picture. Painting a mountain can directly use the stone as a material to print a picture of the stone and so on.

Conclusion

In the future 3D pen applications will bring great creativity to the art world.

To Know more about   Current Trends in Fashion Technology & Textile Engineering

Click here:    https://juniperpublishers.com/ctftte/index.php

To Know more about our Juniper Publishers

Click here: https://juniperpublishers.com/index.php

Lower Psoas Muscle Area is associated with increased mortality after endovascular aneurysm repair in older adults - Juniper Publishers

 

Gerontology & Geriatric Medicine - Juniper Publishers

Abstract

Lower Psoas Muscle Area is associated with increased mortality after endovascular aneurysm repair in older adults.

Introduction: Psoas muscle area (PMA) is an easily measurable surrogate of sarcopenia, which may be associated with mortality and other adverse post-operative outcomes. This study aimed to further explore the relationship between PMA and outcomes post elective infrarenal aortic aneurysm (AAA) endovascular repair of (EVAR) in older adults.

Methods: A retrospective observational study of people aged over 65 years undergoing EVAR for asymptomatic AAA over 5 years. Patients with connective tissue disease, mycotic or inflammatory AAA, emergency or non-elective cases were excluded. The primary outcome was 5-year mortality. Secondary outcomes were 30-day readmissions, post-operative complications, and length of stay.

Results: Ninety-seven patients (mean age 77.5 years, 78% male) were assessed. Adjustment for age, sex and body mass index also showed that patients in the lowest PMA tertile had an increased 5-year mortality (HR 2.76, 95%CI 1.08, 7.03; P=0.034). Adjustment for frailty, measured by modified frailty index, showed only a minimal attenuation of the association (HR 2.30, 95%CI 0.99, 5.34; p=0.054). Being in the lowest PMA tertile did not increase LOS, 30-day readmissions, complications, or influence discharge destination.

Conclusion: The lowest tertile of PMA, as a surrogate marker for sarcopenia, was associated with increased mortality in patients undergoing EVAR for asymptomatic infrarenal AAA, which was only marginally attenuated by frailty adjustment. Although sarcopenia is a complex phenomenon and the literature surrounding it is still evolving, PMA may form one component of risk assessment in patients undergoing EVAR.

Keywords: Frailty; Psoas Muscle Area; Sarcopaenia; Vascular Surgery

Keywords: PMA: Psoas Muscle Area; AAA: Abdominal Aortic Aneurysm; EVAR: Endovascular Aneurysm Repair; LOS: Length of Stay; PMA: Psoas Muscle Area; CT: Computed Tomography; GEKO: Governance Evidence Knowledge Outcomes; SPSS: Statistical Package for the Social Sciences

Introduction

The evolution of abdominal aortic aneurysm (AAA) repair from open to endovascular aneurysm repair (EVAR) has great relevance in older adults, who often have more comorbid conditions, are frailer and have higher levels of sarcopenia. EVAR, where technically feasible and where the maximum aortic diameter has reached threshold (>5.5cm in men and >5.2cm in women) is minimally invasive and involves the deployment of a stent graft inside the aneurysm via percutaneous femoral access, and has several advantages including avoidance of general anesthesia, reduced length of stay (LOS) and reduced postoperative mortality [1].

Sarcopenia and frailty are distinct but overlapping conditions. Frailty is “a biologic syndrome of decreased reserve and resistance to stressors, resulting from cumulative declines across multiple physiologic systems, and causing vulnerability to adverse outcomes” [2]. There have been multiple screening tools developed in an attempt to assess frailty, which usually follow either a phenotypic or cumulative deficits model [3]. Despite the differing tools used to measure frailty, higher frailty scores are associated with increased mortality, post-operative complications, and length of stay in surgical patients [4], higher mortality following open AAA repair and carotid endarterectomy [5] and vascular surgery [6], and LOS and discharge destination in vascular ward patients [7].

Sarcopenia, on the other hand, is defined as “a progressive and generalised skeletal muscle disorder that is associated with an increased likelihood of adverse outcomes including falls, fractures, physical disability and mortality” and “confirmed by the presence of low muscle quantity or quality” [8,9]. Several parameters have been used to define muscle quantity, including psoas muscle area (PMA). A decline in PMA seems to be representative of decreased lean body muscle mass and sarcopenia, at least in haemodialysis patients. However, the European guidelines suggest more research is required to formalise whether PMA is a reasonable surrogate for skeletal muscle mass [10].

There is emerging evidence to suggest that PMA is associated with mortality in older vascular surgical patients following endovascular aortic surgery, and to a lesser extent post-operative complications. Some, but not all studies [11,12], have shown that a reduction in PMA correlated with higher mortality following EVAR, open AAA repair or other vascular intervention [13-21]; but none of the studies to date have included frailty scoring in conjunction with PMA in this setting.

In the AAA population, widespread use of computer tomography (CT) imaging enables easy measurement of PMA as a representation of sarcopenia. PMA could therefore be an easy to obtain predictive tool for outcomes following EVAR, and to determine whether the procedure is in the patient’s favour or not. Our study further explored the relationship between PMA with post-operative outcomes and mortality in older adults undergoing asymptomatic infrarenal EVAR, seeking to assess whether similar correlations between PMA and mortality were found in the local surgical population in Western Australia. We chose to include frailty to further clarify this issue.

Methods

A retrospective observational study of patients 65 years and older who had undergone an elective EVAR for asymptomatic infrarenal AAA, in a tertiary metropolitan centre in Western Australia, from 1st January 2013 to 31st December 2017. Patients were excluded if the cause of the AAA was connective tissue disease, mycosis, or inflammation, and if EVAR was performed as an emergency or non-elective procedure for symptomatic AAA.

Retrospective data was collected from chart review and electronic medical records. Baseline patient characteristics included age, sex, current smoking status, Charlson comorbidity index, the presence of coronary artery disease (history of previous myocardial infarction, coronary artery bypass graft surgery or percutaneous coronary intervention), cerebrovascular disease, chronic kidney disease, diabetes, hypertension, peripheral vascular disease (intermittent claudication, critical limb ischemia, revascularisation or lower limb arteries), as well as, maximum antero-posterior AAA diameter, BMI, and preoperative haemoglobin levels. A modified frailty index (following a cumulative deficits model of frailty) was also calculated for each patient based on information found in medical records. This provided a score out of 11, with a score of 0 indicating an absence of frailty, and a score of 11 indicating the highest level of frailty [22].

PMA was measured at the mid L4 vertebral body on preoperative computed tomography (CT) scans. Where possible, 3mm slice thickness was chosen for measurement, however if this was not possible, 5mm or 1mm slice thickness was chosen. 3mm slice thickness was the most common and thus was the preferred slice thickness for consistency. A radiologist assisted with initial training of one researcher. Following this, the researcher proceeded to calculate the PMA for the rest of the patients. If there were any uncertainties regarding the psoas muscle calculation, the primary researcher verified the measurement with the radiologist.

The primary outcome was survival (calculated as days from operation). Follow up date selected was 31/10/2020. Study end date, the date of final data collection, was 23/02/2021. Determining the survival was based on hospital death records. This was also checked by means of seeing whether the patient had attended subsequent appointments or had subsequent admissions in patients without hospital record of death. This was essential as in Western Australian hospital records as patient death is not always recorded unless the patient has died during a subsequent public hospital admission, or the hospital is formally informed. Patients who could not be confirmed to be alive (or dead) as of the 31/10/2020 were censored in the survival analysis at the last known date that they were alive.

Secondary outcomes were 30-day readmissions related to EVAR, discharge destination (home, residential care, rehabilitation), post-operative complications, and length of stay (LOS) measured in days. This project was approved under the GEKO (Governance, Evidence, Knowledge, Outcomes database used to register information about quality improvement studies and clinical governance) system of WA Health, for projects deemed low- to negligible-risk to patients (GEKO#: 27118).

Statistical Analysis

Results were presented as a measure of central tendency, i.e., median with inter-quartile range, mean with standard deviation or as frequency and proportion. Differences between groups assessed with an independent t-test, non-parametric Mann-Whitney U test, and Fisher’s exact test, where appropriate. Univariate correlations were quantified by Spearman’s (rho) correlation coefficients (Rs). Linear and logistic regression analysis determined the crosssectional association between exposure (PMA) and outcomes. Cox proportional hazards regression analysis determined the uniand multi-variate association between the lowest tertile of psoas size for either sex with mortality. Multivariate models included further adjustment for age, body mass metrics, sex, and other comorbidities associated with mortality.

Statistical significance was set at α=0.05 or 5% level. The statistical analysis was performed on Statistical Package for the Social Sciences (SPSS) Version 22.0 (IBM Corp.; Armonk, NY, USA).

Results

Of the 122 patients identified as having undergone an EVAR procedure, complete data was available for 97 (79.5%). Five patients were excluded as they did not meet inclusion criteria (3 due to age, 2 due to missing information about the type of operation performed). Eighteen patients were excluded as imaging was not available to ascertain PMA data. Although these patients had similar demographics and clinical characteristics to those who were included, the exception was a lower complication rate in the excluded patients, although this failed to reach statistical significance (44% vs. 22%, p=0.06).

The study sample had a median age of 78 years, male preponderance (78.4%), and 79% were ex- or current smokers. Participants had a high prevalence of cardiovascular disease (85%, n=82/97), including coronary disease, cerebrovascular disease, hypertension, and peripheral vascular disease. Complications occurred in 44% of patients - the majority of which were categorized as ‘other’ (that is, not a fall, delirium, venous thromboembolism, bleeding, or infection). Most common was type 1 and 2 endoleak (n=8, with one requiring surgical intervention) and ischaemic complications (n=6 -testicular infarct, 3 non- ST elevation myocardial infarct, ischaemic lower limb, splenic infarct). Twenty-six (27%) patients had died by end of follow up. Twenty-six patients were unable to be confirmed to be alive at the time of follow up (31/10/2020). Median follow-up was 3.7 years with IQR 2.51 to 5.3 years (Range: 0.01 - 8.84 years) (Table 1).

PMA exhibited pronounced age- and gender-specific differences. Female patients and those over >80 years of age had lower PMA. However, median PMA was similar for females patients regardless of age group. PMA was also shown to vary significantly by body mass index, with a higher BMI significantly associated with a higher than median PMA for sex and age. PMA was divided into tertiles, with comparison made between the lower tertile and upper 2 tertiles. Those in the lower tertile (PMA less than 1938 mm2 in males and less than 1202 mm2 in females) tended to be older, with a lower weight and BMI. Degree of frailty as per modified frailty index and comorbidities including cardiovascular disease, hypertension, renal failure, diabetes, and smoking status were similar in both groups. There was no significant difference in complications, readmissions, or LOS between the two groups, and no significant difference in length of follow-up. There was however a significant difference in crude 5-year mortality following operation, with 35% (12) of those in the lowest tertile having died after 5 years compared with 17.5% (11) of those in the upper two tertiles (p=0.049), (Table 2). The lowest tertile of PMA for either sex was associated with 5-year mortality after elective EVAR surgery for asymptomatic infrarenal AAA, as demonstrated by Kaplan Meier survival curve. This was maintained after adjustment for age, sex and BMI as per (Figure 1).

There was a significant association also noted between the lower tertile of PMA for either sex, when adjusted for BMI, for increased risk of death (OR 3.53, 95%CI 1.21 -10.27, p=0.021) and increased LOS (β 0.33, 95%CI 0.04-0.63, p=0.028). However, there was no association between lower tertile PMA for complications in either gender (Table 3).

Sensitivity Analysis

The lowest tertile of PMA for either sex after EVAR was associated with increased risk of 5-year mortality in the unadjusted model (HR 2.31, 95%CI 1.02, 5.24; P=0.045), which remained after adjustment for BMI (HR 2.91, 95%CI 1.16, 7.34; P=0.023) and after adjustment for age, sex, and BMI (HR 2.50, 95%CI 1.03, 6.07; P=0.043). The association between the lowest tertiles of PMA for either sex was attenuated by age-adjustment alone, but the association was strengthened after the inclusion of sex and body mass metrics. Lowest tertile PMA associated with an increased risk of 5-year mortality after adjustment for prevalent diabetes, cardiovascular disease and complications during admission. Modified Frailty Index minimally attenuated the association between lowest tertile of PMA and risk of 5-year mortality after EVAR procedure (Table 4).

Discussion

This study reported a two-to-three-fold increase in 5-year mortality in the lowest tertile of PMA, which was strengthened after adjusting for age, sex, and BMI, in elderly patients undergoing elective EVAR for asymptomatic infrarenal AAA, in a single tertiary centre in Western Australia. This association was also strengthened after adjusting for cardiovascular disease, diabetes, and obesity, but was marginally attenuated with adjustment for frailty. The association between mortality and PMA has been observed in several studies before, showing a similar association between low PMA and higher mortality in the diverse EVAR population. Most studies are single centre, retrospective and heterogenous in nature. Drudi et al (open repair of AAA and EVAR) showed decreased 5-year mortality by 14% for a 1cm2 increase in PMA [14]. Lindstrom et al. (elective and emergency EVAR for infrarenal and more complex AAA) showed a lean PMA (calculated by Hounsfield units multiplied by total PMA) was independently associated with 26% reduced mortality per standard deviation increase of lean PMA, and more strongly associated with mortality than total PMA at L3 (22%) [18] respectively. Newton et al and Oliveira et al, (elective EVAR), also showed an association between the lowest tertile of PMA with increased mortality, with OR of 3.9 [15] and HR of 4.1 respectively [19]. Similarly, Huber et al showed the lowest quartile of PMA was associated with reduced median survival time (65 months vs 91 months) (25). Karkkainen et al (fenestrated-branched EVAR) found reduced lean PMA had inverse correlations with major adverse events and mortality, and further showed in a prospective cohort similar correlation with mid-term survival and quality of life [16,17].

In opposition, Chowdury et al, (vascular patients admitted to vascular unit having had CT abdomen) did not show a link between PMA and mortality and readmission [11]. This opposing result may be due to the heterogeneity of the patient population examined - roughly 52% did not undergo EVAR, lower duration of follow up (12-24 months), and BMI not being accounted for as potential confounder. Indrakusuma et al (asymptomatic infrarenal AAA) did not find an association between PMA and survival in either EVAR/open repair or conservative management groups [12]. However, the surgical cohort was generally younger than other studies and again BMI was not accounted for as a potential confounding factor.

The effect size of our study was smaller than in most other studies. This may be explained by our calculation of PMA by dimension, rather than lean PMA. Lindstrom et al. indicated that a stronger association is found with lean PMA rather than total PMA [18]. Frailty was not assessed in previous studies and differences in outcomes may be explained by differences in frailty. Furthermore, our study was specific to elective infrarenal AAA, whereas other studies had a significantly more heterogenous population, ranging from vascular surgery patients admitted who had CT abdomen, to patients undergoing EVAR for aortic aneurysmal disease in general.

The association between lowest tertile of PMA in either sex with 5-year mortality was attenuated by age-adjustment alone. This may be due to a narrowing of the differences in PMA with increasing age for either sex, or a lack of sufficient study power. The actual number of deaths in each arm was small and the older cohort and expected life expectancy make interpretation difficult. Additionally, “old age mortality advantage”, a phenomenon describing relative improved mortality in those 70-79 years, as compared to younger ages and other countries, may also explain the attenuation [23]. This result is also reflected in other studies [15,16]. Similarly, smoking status (seen in Karkkainen et al.) and the presence of underlying renal disease appeared to attenuate the association of PMA and mortality, again suggesting that PMA may be less useful in predicting mortality outcome in smokers or those with underlying renal disease [16].

The novelty of our study was the simultaneous measurement of frailty which minimally attenuated the association between 5-year mortality and the lowest tertile of PMA suggesting that despite adjusting for frailty, the association between PMA and mortality remains. The impact of frailty, as mentioned previously, has not been formally assessed previously in any other study of PMA and outcomes in vascular patients. This reinforces the message that although there is intuitively a link between PMA / sarcopenia and frailty, the concepts are not interchangeable. It may imply that sarcopenia as assessed by PMA may be a better marker of mortality risk than measures of frailty. Our study did not show statistically significant associations between PMA and postoperative complications, discharge destination and readmissions within 30 days. This may relate to many of the complications being technical or procedure related rather than due to lack of physiological reserve. The only studies looking at PMA and have published complication rates show overall surgical complication rates of 21.9% [18] and ‘post-operative complication’ of 27% [15]. Although this is much lower than our study, it is difficult to compare these as the former study references both open and endovascular aneurysm repair and the latter study does not describe what they mean by ‘post-operative complications’. The lack of association with complications would more likely be reinforced by the difference noted in complication rate in those patients who were excluded from the study due to lack of PMA data

There was a statistically significant association found between PMA and LOS after adjusting for BMI, however it is unlikely to be clinically significant at 8 hours or approximately one third of a day. Chowdury et al. did not show correlation with LOS or discharge destination, similar to this study [11]. However, this does contrast with Karkkainen et al [16]. The increased complexity of the operation (fenestrated-branched EVAR for thoracic and pararenal aneurysms) may account for this, as well as the larger sample size (n=504).

There is no clear consensus as to which value of PMA leads to increased mortality and poorer outcomes (8). In this study, the lowest tertile of PMA for men was less than 19.4 cm2 and for women, less than 12cm2. Other studies that have examined total psoas muscle area have a cut off for the lowest tertile of PMA at 13cm2 and 24cm2, both measured at L4, which is the level we chose [14,15]. We also showed that PMA to be associated with age, sex and BMI as did all previous studies mentioned. The limitations to our study include: the retrospective nature of the study at a single metropolitan centre; the small sample size which contributes to lower statistical power; and missing data as a potential source of bias. Furthermore, European consensus guidelines on sarcopenia have been recently updated to place more emphasis on muscle strength (potentially measured by grip strength or chair stand test), with poor muscle performance (potentially measured by low gait speed) defining severe sarcopenia [8]. These new measures should be included in future studies [24-30].

Conclusions

Lower PMA is associated with 2.76 times increased mortality in patients undergoing EVAR for asymptomatic infrarenal AAA. However, it did not predict shorter term outcomes. Despite adjusting for frailty, this association with PMA and mortality remains, which has not previously been assessed in other studies. Low PMA would be considered as less than 19.4cm2 in men and less than 12cm2 in women in this study, however further studies are required to determine what PMA would be best representative of sarcopenia and significantly worse mortality. As patients undergoing EVAR routinely have pre-operative CT scanning, PMA is an easy way to assess sarcopenia and to determine risk for operative management of these patients adding additional valuable information to risk stratification and indication for treatment in this group.

To Know more about   Open Access Journal of Gerontology & Geriatric Medicine

Click here:    https://juniperpublishers.com/oajggm/index.php

To Know more about our Juniper Publishers

Click here: https://juniperpublishers.com/index.php

 

The Interrelationship between Perceived Stress Level, Sleep Quality, and Academic Performance among Students of a Caribbean Medical School - Juniper Publishers

Anatomy Physiology & Biochemistry - Juniper Publishers

Abstract

Objective: Stress and sleep are essential elements of life and how these two factors affect academic performance of medical students must be studied properly in order to maximally and efficiently facilitate the medical training of future physicians.

Methods: 77 medical students who had similar work-load participated in this study. Participants were asked to answer the Pittsburgh Sleep Quality Index (PSQI) questionnaire and the Perceived Stress Scale questionnaire. The analyzed variables, quality of sleep and individual subjective perception of stress were linked to students’ grade point average (GPA). The SPSS version 24 was used for the regression analysis and determination of a Pearson correlation coefficient between perceived stress level, sleep quality, and academic performance.

Results: The majority of participants (80%) experienced a moderate level of stress but the correlation between a perceived stress level and GPA was not found (p>0.7). The distribution of sleep quality among showed that 58% of students described good quality of sleep. There was a correlation (R= -0.67) between the PSQI and GPA (p<0.03), supporting a relationship between higher GPA and good sleep quality.

Conclusion: Adequate sleep is imperative to learning and it is evidenced that a reasonable amount of stress is not only realistic but may also be advantageous to the learning process. Therefore, both sleep and stress interact in a mutual fashion and affect memory retention, and by extension, learning.

Keywords: Preceived stress; Oxidative stress; Physicians; Long-term memory; Physiological responses

Abbrevations: PSQI: Pittsburgh Sleep Quality Index; GPA: Grade Point Average; TSOM: Trinity School of Medicine

Introduction

Stress is a part of our life, since the most elementary bodily reactions produce oxidative stress. Psychologist Richard Lazarus defined stress as a moment in which a person perceives that the “demands exceed the personal and social resources that the individual is able to mobilize” [1]. It would be wrong to say that stress is completely bad, since some stress is beneficial in the learning process and memory consolidation [2]. However, the problem arises when there is too much stress, which ironically becomes counter-productive in the learning process and in long-term memory retrieval [2].

In a similar fashion, sleep is also a vital part of life as well [3,4]. The National Sleep Foundation has found that staying awake for twenty-four hours yields reaction times equivalent to having a blood alcohol concentration of 0.10, which is greater than the legal driving limit in the United States [5]. Sleep also plays a crucial role in memory consolidation, or stabilization, which includes integrating recently encoded memories into existing memory networks, as well as the development of hippocampal independence for declarative memories [6]. So, stress and sleep are essential elements of life and we may stand to benefit from studying how the two factors affect the mind and memory in medical students, in order to maximally and efficiently facilitate the medical training of future physicians.

Materials and Methods

The study was conducted at Trinity School of Medicine (TSOM), Saint Vincent & the Grenadines. The subjects were seventy-seven medical students with mean age of 24.7 years (SD=2.3), 33 male and 44 females, who had a similar academic load. Participation in the study was voluntary, and informed consent was obtained from all participants. Students who did not give consent and those who filled the questionnaire incompletely were excluded from this study. The analyzed variables, quality of sleep and individual subjective perception of stress were linked to students’ grade point average (GPA). Participants were asked to answer the Pittsburgh Sleep Quality Index (PSQI) questionnaire [7], which consisted of 10 questions related to their normal sleep habits. Sleep quality was considered bad for individuals who obtained a score higher than 5. The Perceived Stress Scale [8] was used for an evaluation of the level of stress. This scale includes 10 items and uses 5 points, rating scale ranging from 0 to 4: 0 – never; 1- almost never; 2- sometimes; 3- fairly often; 4 - very often; items 4, 5, 6, 7, and 8 are reversed scored. Data obtained were interpreted regarding the following scale: 0-13 - low-stress level; 14-26 - moderate stress level; 27- 40 - high-stress level. All data were tabulated in Microsoft Excel. The SPSS version 24 was used for the regression analysis and determination of a Pearson correlation coefficient between perceived stress level, sleep quality, and academic performance. A P<0.05 was considered as statistically significant.

Results

The distribution of perceived stress level among TSOM students showed that the majority of participants (80%) experienced a moderate level of stress, 13% of participants had a high stress level and only 7% of students were not stressed out (Figure 1) Several studies were conducted to identify the sources of stress among medical students and the most stressful conditions were found to be related also to medical training rather than social or personal issues [3,9]. Stress in medical students has been a global problem [10].

We also found that there is no correlation between a perceived stress level and GPA (p>0.7). Figure 2 indicates that students with moderate stress level (14-26) had a GPA which ranged from 4.0 to 1.0. These data also supported by several reports in the published literature as stress has physical and emotional effects and can create a positive or negative influence on us [3,11]. The stress responses differ depending on the type of stress and the individual’s physiological responses. Some researchers have explored the impact of stress on student’s performance with respect to change in time period and identified that initially there exists a positive relationship between stress and students’ performance to some specific limit after which stress impacts an academic performance negatively [12].

The distribution of sleep quality among TSOM students showed that a majority of participants (58%) had a good sleep quality (Figure 3), which had a positive effect on a students’ GPA (Figure 4). There was a correlation (R= -0.67) between the PSQA and GPA (p<0.03), supporting a relationship between higher GPA and good sleep quality (Figure 4). There is a correlation (R= -0.37) between the PSQA and perceived stress level (p<0.001), which is an indication that heightened levels of perceived stress and poor sleep quality are inter-related (Figure 5).

Discussion

Previous studies have reported a high prevalence of stress in medical students, ranging from 30% to 50% [13, 14]. A student can be stressed due to different reasons or stressors such as academic, financial or health problems, loss of a close family member or friend. Stress in academic situation can have both positive and negative consequences and can be viewed as the bodies’ reaction both neurologically and physiologically to adapt to the new circumstance [15]. Academic stress is the product of a combination of academic related demands that exceed the adaptive resources available to an individual. If a student is unable to cope effectively with academic stress, then serious psychosocial emotional health consequences may result [16,17]. Students who experience mental and physical health problems are then at greater risk for poor academic performance, thus increasing academic stress and perpetuating a cycle of stress, maladaptive coping, and compromised health [3,18]. In addition, some studies have shown that stress can induce a change in the way that memories are recorded and consolidated, namely going from a “cognitive” hippocampal bias toward a “habitual” dorsal striatal pathway [19].

Among several hypotheses [10,20,21], it was suggested that sleep is involved in the processes of brain plasticity for memory consolidation. Memory consolidation is defined as the time dependent process that converts labile memory traces into more permanent and or enhanced forms [22]. In this hypothesis, the information acquired during wakefulness would be actively altered, restructured and strengthened during sleep. Consolidation and encoding of memories are very important for medical education, as medical students need to retain a substantial amount of complex factual knowledge within short period of time [23]. A review by Curcio et al. in 2006 suggested that student learning and academic performance are closely linked to sleep quality and quantity [24]. A study conducted among medical students in King Saud University of Saudi Arabia showed that decreased nocturnal sleep time, late bedtimes during weekdays, and increased daytime sleepiness were negatively associated with their academic performance [25]. These results and results of our research suggested that students with later sleep phase, disorganized daily schedule/ time management and poorer sleep quality are at a higher risk of impaired academic performance [3,26,27]. The University of Munich (Germany) also detected that the timing of sleep-wake behavior was an important predictor of medical school performance [27].

Conclusion

Considering the data of this study and literature review, it is clearly apparent that the learning process and memorization of information require a certain amount of good quality sleep [3,6,23- 27]. The sleep quality and its duration play a tremendous role in the consolidation of procedural memory (a part of a long-term memory) and episodic memory and is a key point in the academic success [24]. Therefore, medical students must not neglect sleep during their academic life, and they should also try to minimize unnecessary stress, as the results of this study showed a negative effect of increased stress level on sleep quality and academic performance. According to this study, students whose stress level exceeded an adaptive threshold experienced academic difficulties and lowered GPA, but for another cohort of students the moderate stress level helped to enhance learning ability and GPA.

Adequate sleep is imperative to learning and it is evidenced that a reasonable amount of stress is not only realistic but may also be advantageous to the learning process. Therefore, both sleep and stress interact in a mutual fashion and affect memory retention, and by extension, learning.

To Know more about   Anatomy Physiology & Biochemistry International Journal

Click here:    https://juniperpublishers.com/apbij/index.php

To Know more about our Juniper Publishers

Click here: https://juniperpublishers.com/index.php