A decomposition of light's spin angular momentum density.

Light carries intrinsic spin angular momentum (SAM) when the electric or magnetic field vector rotates over time. A familiar vector equation calculates the direction of light's SAM density using the right-hand rule with reference to the electric and magnetic polarisation ellipses. Using Maxwell's equations, this vector equation can be decomposed into a sum of two distinct terms, akin to the well-known Poynting vector decomposition into orbital and spin currents. We present the first general study of this spin decomposition, showing that the two terms, which we call canonical and Poynting spin, are chiral analogies to the canonical and spin momenta of light in its interaction with matter. Like canonical momentum, canonical spin is directly measurable. Both canonical and Poynting spin incorporate spatial variation of the electric and magnetic fields and are influenced by optical vortices. The decomposition allows us to show that a linearly polarised vortex beam, which has no total SAM, can nevertheless exert longitudinal chiral pressure due to equal and opposite canonical and Poynting spins.

The Impact of Bariatric Surgery on Nitrogen Balance at Six months Post-surgery.

PURPOSE: Obesity, defined as abnormal or excessive fat accumulation that presents a risk to health, rose from 8.6 to 10.5% in Singapore's residents. Bariatric surgery, the primary treatment for severe obesity, induces fat and muscle loss. Adequate protein intake is vital for preventing muscle loss. This study examines nitrogen balance in individuals with obesity pre- and post-surgery. MATERIALS AND METHODS: Sixteen participants with severe obesity (BMI ≥ 32.5 kg/m2) undergoing bariatric surgery (14 sleeve gastrectomy, 2 Roux-en-Y gastric bypass) and 20 normal-weight controls (BMI < 25 kg/m2) were recruited. Nitrogen balance, calculated from dietary protein intake and urine nitrogen excretion, was assessed. Participants with obesity were re-evaluated 6 months post-surgery. Data were analyzed using parametric methods. RESULTS: At baseline, controls had a BMI of 20.8 ± 2.1 kg/m2; those with obesity had 40.9 ± 7.3. Daily calorie and protein intake for participants with obesity were not statistically significantly different from controls (calorie intake at 1467 ± 430 vs. 1462 ± 391 kcal, p = 0.9701, protein intake 74.2 ± 28.7 vs. 64.6 ± 18.3 g, p = 0.2289). Post-surgery, BMI, fat-free mass, fat mass, total energy intake, carbohydrate, and protein intake decreased significantly (p < 0.01). Protein oxidation and urine nitrogen excretion did not change after bariatric surgery. However, nitrogen balance significantly reduced from 2.62 ± 5.07 to - 1.69 ± 5.07 g/day (p = 0.025). CONCLUSION: Dietary protein intake is inadequate in individuals with obesity at 6 months post-bariatric surgery and contributes to a state of negative nitrogen balance.

Long COVID and its associated factors among COVID survivors in the community from a middle-income country-An online cross-sectional study.

Patients with COVID-19 usually recover and return to normal health, however some patients may have symptoms that last for weeks or even months after recovery. This persistent state of ill health is known as Long COVID if it continues for more than three months and are not explained by an alternative diagnosis. Long Covid has been overlooked, especially in the low- and middle-income countries. Therefore, we conducted an online survey among the COVID-19 survivors in the community to explore their Long COVID symptoms, factors associated with Long COVID and how Long COVID affected their work. A total of 732 COVID-19 survivors responded, with 56% were without or with mild symptoms during their acute COVID-19 conditions. One in five COVID-19 survivors reported of experiencing Long COVID. The most commonly reported symptoms were fatigue, brain fog, depression, anxiety and insomnia. Females had 58% higher odds (95% CI: 1.02, 2.45) of experiencing Long COVID. Patients with moderate and severe levels of acute COVID-19 symptoms had OR of 3.01 (95% CI: 1.21, 7.47) and 3.62 (95% CI: 1.31, 10.03) respectively for Long COVID. Recognition of Long COVID and its associated factors is important in planning prevention, rehabilitation, clinical management to improve recovery from COVID-19.

Revisional Surgery or Pharmacotherapy for Insufficient Weight Loss and Weight Regain After Primary Bariatric Procedure: a Descriptive Study.

PURPOSE: Bariatric surgery is the most effective and durable treatment option for clinically severe obesity. Unfortunately, some degree of weight regain (WR) is common after nadir weight is achieved. Pharmacotherapy and revision surgery are potential options to treat this phenomenon. We aim to determine the efficacy of both approaches in patients with WR versus insufficient weight loss (IWL). MATERIALS AND METHODS: We retrospectively reviewed a prospectively collected database of patients who underwent bariatric surgery from 2008 to 2018 with IWL or WR. RESULTS: Of 422 patients with WR or IWL after bariatric surgery, 150 patients were placed on pharmacotherapy and 27 underwent revisional surgeries. Mean age of patients was 41.4 years and mean BMI was 42.1 kg/m2. The most common conversion surgery was LSG to RYGB. % Total weight loss (TWL) was higher in IWL group (23.8% ± 11.0) compared to WR group (17.2% ± 7.9) in revisional surgery (p = 0.02). The converse was observed for pharmacotherapy, with %TWL 1.9% in the WR group compared to 0.7% in the IWL group (p = 0.0067). CONCLUSION: Patients with IWL or WR had modest weight loss with adjunctive use of pharmacotherapy after primary bariatric surgery. Conversely, revisional surgery is an effective treatment for both IWL and WR.

Endoscopic internal drainage with double pigtail stents for upper gastrointestinal anastomotic leaks: suitable for all cases?

BACKGROUND/AIMS: Surgeons and endoscopists have started to use endoscopically inserted double pigtail stents (DPTs) in the management of upper gastrointestinal (UGI) leaks, including UGI anastomotic leaks. We investigated our own experiences in this patient population. METHODS: From March 2017 to June 2020, 12 patients had endoscopic internal drainage of a radiologically proven anastomotic leak after UGI surgery in two tertiary UGI centers. The primary outcome measure was the time to removal of the DPTs after anastomotic healing. The secondary outcome measure was early oral feeding after DPT insertion. RESULTS: Eight of the 12 patients (67%) required only one DPT, whereas four (33%) required two DPTs. The median duration of drainage was 42 days. Two patients required surgery due to inadequate control of sepsis. Of the remaining 10 patients, nine did not require a change in DPT before anastomotic healing. Nine patients were allowed oral fluids within the 1st week and a soft diet in the 2nd week. One patient was allowed clear oral feeds on the 8th day after DPT insertion. CONCLUSION: Endoscopic internal drainage is becoming an established minimally invasive technique for controlling anastomotic leak after UGI surgery. It allows for early oral nutritional feeding and minimizes discomfort from conventional external drainage.

Intranasal Steroid Use and Satisfaction in Allergic Rhinitis: A Cross-Sectional Study from an Asian Perspective.

BACKGROUND: Intranasal steroid (INS) is the most effective medication class for controlling allergic rhinitis (AR) symptoms; however, its effectiveness is limited by patient compliance. Previous studies have explored INS use, compliance, satisfaction, and experience. There is, however, no Asian study on these factors in entirety. OBJECTIVE: We aimed to investigate the rate of compliance to usage of INS and explore the reasons for noncompliance in our local population. METHODS: We conducted a prospective cross-sectional study on 65 AR patients in a tertiary hospital. Recruited patients were administered a questionnaire to collect data about symptoms, INS use, and concerns they may have. Statistical analysis was performed using SPSS. RESULTS: The overall compliance rate to INS was 63.1%. Noncompliance was associated with increased frequency of dosing (p = 0.050), presence of sensory attributes (p = 0.041), and forgetfulness (p = 0.049). The top 3 most frequent sensory attributes experienced by patients include throat rundown (29.2%), aftertaste (21.5%), and immediate taste (20.0%). There was a significant difference between brands of INS with regard to sensory attributes experienced (p = 0.003) but no side effects (p = 0.070). CONCLUSIONS: Identifying risk factors for noncompliance to INS can help health-care providers address difficulties faced by patients and hence increase compliance, allowing better control of AR symptoms.

Small hiatal hernia and postprandial reflux after vertical sleeve gastrectomy: A multiethnic Asian cohort.

BACKGROUND: Laparoscopic vertical sleeve gastrectomy (LSG) is a popular bariatric procedure performed in Asia, as obesity continues to be on the rise in our population. A major problem faced is the development of de novo gastroesophageal reflux disease (GERD) after LSG, which can be chronic and debilitating. In this study, we aim to assess the relationship between the presence of small hiatal hernia (HH) and the development of postoperative GERD, as well as to explore the correlation between GERD symptoms after LSG and timing of meals. In doing so, we hope to gain a better understanding about the type of reflux that occurs after LSG and take a step closer towards effectively managing this difficult to treat condition. METHODS: We retrospectively reviewed data collected from patients who underwent LSG in our hospital from Dec 2008 to Dec 2016. All patients underwent preoperative upper GI endoscopy, during which the identification of hiatal hernia takes place. Patients' information and reflux symptoms are recorded using standardized questionnaires, which are administered preoperatively, and again during postoperative follow up visits. RESULTS: Of the 255 patients, 125 patients (74%) developed de novo GERD within 6 months post-sleeve gastrectomy. The rate of de novo GERD was 57.1% in the group with HH, and 76.4% in the group without HH. Adjusted analysis showed no significant association between HH and GERD (RR = 0.682; 95% CI 0.419 to 1.111; P = 0.125). 88% of the patients who developed postoperative GERD reported postprandial symptoms occurring only after meals, and the remaining 12% of patients reported no correlation between the timing of GERD symptoms and meals. CONCLUSION: There is no direct correlation between the presence of small hiatal hernia and GERD symptoms after LSG. Hence, the presence of a small sliding hiatal hernia should not be exclusion for sleeve gastrectomy. Electing not to perform concomitant hiatal hernia repair also does not appear to result in higher rates of postoperative or de novo GERD.

Resolution of Erosive Esophagitis After Conversion from Vertical Sleeve Gastrectomy to Roux-en-Y Gastric Bypass.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) has become the preferred bariatric procedure in many countries. However, there is one shortcoming of LSG in the long-term follow-up, and this is the onset of gastro-esophageal reflux disease (GERD) and erosive esophagitis (EE). Conversion to Roux-en-Y gastric bypass (RYGB) is considered an option in patients unresponsive to medical therapy. Currently, there is no evidence of EE improvement or resolution after conversion surgery. In this study, we objectively evaluate the effectiveness of RYGB in management of EE with upper endoscopy (EGD) to identify the significant variables in patients with GERD symptoms post LSG refractory to medical therapy and require conversion surgery. METHODS: Over a period of 11 years (2008-2019) at Singapore General Hospital, we retrospectively reviewed a prospectively collected database of a cohort of patients whom had conversion surgery to RYGB for refractory GERD and EE after LSG. Patient's endoscopic findings and demographic and anthropometric data were analyzed. RESULTS: We identified a total of 14 patients who underwent LSG to RYGB conversions for endoscopic proven erosive esophagitis in our unit during the study period. Eight patients (57.1%) had concurrent hiatal hernia repaired. Nine (64.3%) patients were females. The median age of patients in this cohort was 44 (range 30-61) years. Mean weight and BMI were 87.7 kg (± 19.2) and 32.8 (± 3.09) kg/m2, respectively, on the day of conversion surgery. The median time between LSG and revision to RYGB was 36 (range 6-68) months. Seven patients (50%) had complete resolution of GERD symptoms after conversion, and 6 patients (42.9%) had partial resolution. Six out of 7 patients had complete resolution of EE. There were 4 anastomotic strictures (28.6%). Older patients, Indian ethnicity, present of hiatal hernia and lower weight loss after initial LSG were more likely to undergo conversion surgery. CONCLUSION: Conversion to RYGB after LSG is clinically relevant and may be a feasible solution if patients have ongoing GERD refractory to medical therapy. Ninety-three percent of our patients achieved complete resolution of their GERD symptoms and significant improvement of erosive esophagitis with significant weight loss after conversion. This study has important implications as LSG is increasingly being performed and a proportion of these will need revision surgery for various reasons, particularly GERD which is extremely prevalent.

Precision Delivery of Multiscale Payloads to Tissue-Specific Targets in Plants.

The precise deployment of functional payloads to plant tissues is a new approach to help advance the fundamental understanding of plant biology and accelerate plant engineering. Here, the design of a silk-based biomaterial is reported to fabricate a microneedle-like device, dubbed "phytoinjector," capable of delivering a variety of payloads ranging from small molecules to large proteins into specific loci of various plant tissues. It is shown that phytoinjector can be used to deliver payloads into plant vasculature to study material transport in xylem and phloem and to perform complex biochemical reactions in situ. In another application, it is demonstrated Agrobacterium-mediated gene transfer to shoot apical meristem (SAM) and leaves at various stages of growth. Tuning of the material composition enables the fabrication of another device, dubbed "phytosampler," which is used to precisely sample plant sap. The design of plant-specific biomaterials to fabricate devices for drug delivery in planta opens new avenues to enhance plant resistance to biotic and abiotic stresses, provides new tools for diagnostics, and enables new opportunities in plant engineering.

A case of gastric cancer after sleeve gastrectomy.

There is concern over how to survey the remnant upper gastrointestinal tract, as well as what to do if a patient subsequently develops an upper gastrointestinal cancer following bariatric surgery. We hereby report a case of gastric cancer arising 8 years after a laparoscopic sleeve gastrectomy (LSG). The patient, a 42 year-old woman, was diagnosed with a gastric cancer via esophagogastroduodenoscopy (EGD). As such, she underwent a laparoscopic total gastrectomy with lymphadenectomy. The final histopathology was that of a poorly differentiated adenocarcinoma with signet-ring cells without lymph node metastases (staging pT4aN0). The background gastric mucosa displayed no Helicobacter pylori. There have only been a few reported cases of gastric cancer after sleeve gastrectomy. Nevertheless, it may be wise to consider performing EGD at regular intervals after bariatric surgery, especially in Asia. In this regard, LSG holds an advantage over Roux-en-Y gastric bypass with respect to the feasibility of surveillance of the remnant stomach.

A bioinspired approach to engineer seed microenvironment to boost germination and mitigate soil salinity.

Human population growth, soil degradation, and agrochemical misuse are significant challenges that agriculture must face in the upcoming decades as it pertains to global food production. Seed enhancement technologies will play a pivotal role in supporting food security by enabling germination of seeds in degraded environments, reducing seed germination time, and boosting crop yields. So far, a great effort has been pursued in designing plants that can adapt to different environments and germinate in the presence of abiotic stressors, such as soil salinity, heat, and drought. The technology proposed here seeks a different goal: To engineer the microenvironment of seeds by encapsulation, preservation, and precise delivery of biofertilizers that can boost seed germination and mitigate abiotic stressors. In particular, we developed a biomaterial based on silk fibroin (S) and trehalose that can be mixed with rhizobacteria and applied on the surface of seeds, retrofitting currently used techniques for seed coating, i.e., dip coating or spray drying. A micrometer thick transparent robust coating is formed by material assembly. The combination of a polymorphic protein as S and of a disaccharide used by living systems to tolerate abiotic stressors provides a beneficial environment for the survival of nonspore forming rhizobacteria outside the soil and in anhydrous conditions. Using Rhizobium tropici CIAT 899 and Phaseolus vulgaris as working models, we demonstrated that rhizobacteria delivered in the soil after coating dissolution infect seedlings' roots, form root nodules, enhance yield, boost germination, and mitigate soil salinity.

Attitudes and perceptions of the general public on obesity and its treatment options in Singapore.

Data on attitudes and perceptions towards obesity are lacking in Asia. Participants who attended an obesity public forum were surveyed concerning obesity and its treatment options. Although obesity is generally accepted as a disease with biological underpinnings such as hormonal imbalances and slow metabolic rate, it is also regarded as an issue of personal responsibility. 65.1% believed that weight-loss medications are dangerous. 20.6% thought that pharmacotherapy is effective for weight loss, whereas 41.1% were unsure. Most believed that bariatric surgery could improve health (81.9%) and diabetes control (74.0%) although 64.1% were unsure of its risks.

Correlation Between Symptomatic Gastro-Esophageal Reflux Disease (GERD) and Erosive Esophagitis (EE) Post-vertical Sleeve Gastrectomy (VSG).

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) has become the preferred bariatric procedure in many countries. However, there is one shortcoming of LSG in the long-term follow-up and this is the onset of GERD and erosive esophagitis (EE). Current evidence of the effect of SG on GERD did not consolidate to a consensus. In this study, we objectively evaluate the incidence of EE 1 year post-LSG with upper endoscopy (EGD) and try to identify the significant variables and possible underlying mechanisms of the EE post-LSG. METHODS: Over a period of 5 years (2011-2016) at Singapore General Hospital, we retrospectively reviewed a prospectively collected database of a cohort of patients whom had LSG by a single surgeon who routinely performed EGD pre-operative and 1 year post-operative to assess EE and hiatal hernia. Patient's endoscopic findings and demographic and anthropometric data were analyzed. RESULTS: We identified a total of 97 obese patients who underwent LSG at our hospital by studied surgeon. Sixty-three patients (64.9% of original sample) were finally evaluated in the present study, 40 (59.7%) of whom were female. The mean (range) age of patients was 38.2 (18-66) years, and mean BMI was 36.3 ± 4.1 kg/m2. Median time to follow-up EGD was 13 months (range, 12-15). Following LSG, there was a significant decrease in both BMI (42.1 ± 1.2 vs. 29.9 ± 1.0 kg/m2) and percentage excess weight loss of 56.6 ± 3.6%. The prevalence of EE on endoscopy increased from 9 (14.3%) to 28 (44.4%) patients. Of which 15 (23.8%) were grade A, 11 (17.5%) were grade B, and 2 (3.2%) were grade C. There was no correlation between GERD symptoms with EE; however, our study found a trend suggesting higher prevalence of EE with a sleeve diameter measuring > 2 cm wide (p = 0.069). CONCLUSION: Although LSG is effective in treating obesity and its metabolic syndromes, the prevalence of EE increased significantly 1 year after the surgery. Since we do not fully understand the long-term impact of chronic esophagitis in post-sleeve population, we recommend follow-up EGD assessment post-operatively and treat the esophagitis if present.

Comprehensive Assessment of the Effects of Sleeve Gastrectomy on Glucose, Lipid, and Amino Acid Metabolism in Asian Individuals with Morbid Obesity.

BACKGROUND: Obesity-induced insulin resistance leads to abnormalities in glucose, lipid, and amino acid metabolism. Our study examined the differences in insulin-mediated glucose, amino acid, and lipid metabolism between morbidly obese subjects with non-obese controls and the associated changes following sleeve gastrectomy (SG). METHODS: Non-obese controls and individuals with morbid obesity and scheduled for SG were recruited. Metabolic assessments were performed for all subjects at baseline and at 6 months after SG for eight subjects. The hyperinsulinemic-euglycemic clamp technique together with comprehensive metabolomic profiling was used to quantify insulin-mediated glucose, amino acid, and lipid metabolism. RESULTS: Eleven morbidly obese non-diabetic subjects scheduled for SG and nine non-obese controls were recruited. Compared to controls, obese subjects had significantly lower glucose uptake (4.4 ± 0.6 vs. 17.3 ± 2.4 mg/kg FFM/min per µU/mL·100) and higher concentration of branched-chain amino acids (BCAAs, 332.5 ± 26.8 vs. 235.3 ± 11.0 µM), non-esterified fatty acid (52.9 ± 9.9 vs. 25.6 ± 6.7 µM), and lipid-related acylcarnitines (intermediate chain 389.8 ± 32.5 vs. 285.9 ± 20.5; long chain 301.7 ± 22.1 vs. 236.0 ± 13.3 nM) during insulin clamp. Body weight significantly reduced at 6 months after bariatric surgery (92.5 ± 6.3 vs. 115.2 ± 6.9 kg), together with improvements in insulin-mediated glucose uptake, and suppression of BCAAs, non-esterified fatty acids, and lipid-related metabolites. CONCLUSIONS: Morbid obesity in Asian individuals was associated with impairment in the regulatory actions of insulin on glucose, amino acid, and lipid metabolism, and these obesity-induced regulatory dysfunctions improved significantly 6 months after SG.

Five-year long-term clinical outcome after bariatric metabolic surgery: A multi-ethnic Asian population in Singapore.

Bariatric surgery is an effective treatment for morbid obesity and its metabolic related comorbidities; type 2 diabetes, hypertension and hyperlipidaemia.1 However, the literature is scarce regarding the long-term outcome after bariatric surgery, especially among multi-ethnic Asian populations. Considering the growing number of bariatric metabolic surgeries in Asia, we have attempted to provide a regional perspective on 5-year long-term clinical outcomes post bariatric surgery in Singapore. Between 2010 and 2016, all bariatric operative cases were included, and these comprised: laparoscopic sleeve gastrectomy (LSG), 393; laparoscopic Roux-En-Y gastric bypass (RYGB), 125; laparoscopic mini-gastric bypass (MGB), 43. The primary outcome measure was the percentage of excess weight loss (% EWL) at 6 months, 1, 2, 3, 4 and 5 years, with % remission of type 2 diabetes mellitus (T2DM) at 1 year following LSG (49.7%, 61.2%, 56.1%, 47.8%, 40.8% and 47.3%; 82.2%), RYGB (60.2%, 62.1%, 57.6%, 50.1%, 48.7% and 47.7%; 86.9%) and MGB (58%, 68.1%, 62.7%, 66.2%, 64.0%, 65.2%; 71.9%). In conclusion, MGB and RYGB showed the greatest % EWL at 5 years and are recommended for moderate T2DM. LSG is an effective bariatric operation with a high % EWL up to 2 years, and a high remission rate of mild T2DM. The remission rate of T2DM was equally high in all 3 surgical groups, independent of ethnic differences.