In the present paper, a novel unconstrained higher-order theory (UCHOT) is applied to analyse the free vibration of cylindrical sandwich shells with nanocomposite face sheets reinforced with graphene ...platelets. UCHOT considers the shear and thickness deformations. It is assumed that the cylinder includes a soft core which embedded between functionally graded graphene platelets reinforced composites (FG-GPLRC). FG-GPLRC face sheet consists of several laminas that the GPL weight fraction is modified layer to layer based on the various functionally graded (FG) patterns. The Winkler-Pasternak elastic foundation is located at the inner surface of the shell. Highly coupled motion equations are solved by a semi-analytical approach. This approach is blended of the generalized differential quadrature and trigonometric expansion (TE-GDQ) methods. Solving the obtained eigenvalue problem, corresponding frequencies to the cylindrical sandwich shell are achieved. In the results part, comparison studies are carried out to indicate the validity and performance of the selected theory and solution method. Afterward, some parametric results are demonstrated to investigate the impacts of shell theory order, geometrical parameters, FG model, elastic foundation parameters, and boundary conditions on the frequency response of the mentioned structure.
Abstract
Background
Bariatric surgery has been widely indicated for the management of obesity and related comorbidities. However, there are uncertainties pertaining to the risks of post-bariatric ...severe hypoglycaemia (SH), cardiovascular diseases (CVDs), end-stage kidney diseases (ESKDs) and all-cause mortality in obese patients with Type 2 diabetes mellitus (T2DM), especially among Asian populations.
Methods
A retrospective population-based cohort of 1702 obese T2DM patients who were free of CVD and ESKD were assembled based on the 2006–17 Hospital Authority database. One-to-five propensity-score matching was used to balance baseline covariates between patients in bariatric surgery and control groups. Incidence rates (IRs) of SH, CVD, Stage 4/5 chronic kidney diseases (CKD), ESKD and all-cause mortality events for two groups were calculated. Hazard ratios (HR) for SH, CVD and Stage 4/5 CKD events were assessed using Cox-proportional hazard models. Changes in estimated glomerular filtration rate (eGFR) and urine albumin–creatinine ratio (UACR) were measured up to 60 months.
Results
Over a mean follow-up period of 32 months with 5725 person-years, cumulative incidences of mortality, CVD, Stage 4/5 CKD, ESKD and SH were 0, 0.036, 0.050, 0.017 and 0.020, respectively. The surgery group had a significant reduction in risk of CVD events (HR = 0.464, P = 0.015) and no occurrence of mortality events. However, there were no significant differences in risks of SH HR = 0.469, 95% confidence interval (CI): 0.204–1.081, Stage 4/5 CKD (HR =0.896, 95% CI: 0.519–1.545) and ESKD (HR = 0.666, 95% CI: 0.264–1.683) between two groups, although IRs were lower in the surgery group. Surgical patients had significantly higher eGFR within 12 months and had significantly lower UACR until 48 months.
Conclusions
Among obese T2DM patients, bariatric surgery lowered the risk of CVD and mortality, and was beneficial towards the kidney outcomes.
Summary
Background
Obesity control in Prader‐Willi syndrome (PWS) is notoriously difficult. The role of bariatric surgery in PWS remains controversial as long‐term data are lacking.
Objectives
To ...evaluate the 10‐year outcomes of bariatric surgery in PWS.
Methods
This was a prospective observational study on PWS patients who received bariatric surgery and multidisciplinary follow‐up programmes for obesity control. Outcomes on weight reduction and comorbidity resolution were evaluated.
Results
Between 2008 and 2013, five PWS patients (two males, mean age 19.2 ± 3.0 years) with body mass index of 47.3 ± 6.9 kg m−2 received sleeve gastrectomy (n = 2), one anastomosis gastric bypass (n = 2), and Roux‐en‐Y gastric bypass (n = 1) after failing all non‐operative weight loss programmes. The median follow‐up was 8.4 ± 2.2 years. The best mean percentage of total weight loss (%TWL) was achieved at 2 years (24.7%). %TWL dropped to 23.3% at 3 years, 11.9% at 5 years, 4.1% at 8 years, and 0% at 10 years. Each patient had at least three comorbidities preoperatively, but none of them had resolution of any one of the comorbidities at the last follow‐up.
Conclusions
Bariatric surgery could not produce sustainable long‐term weight loss or comorbidity resolution in PWS. This study suggests that bariatric surgery cannot be recommended to PWS patients as a standard treatment.
OBJECTIVE
To report the clinical spectrum seen in young abusers of street‐ketamine (regular recreational abusers of street‐ketamine, for its hallucinogenic effects) in Hong Kong, presenting with ...significant lower urinary tract symptoms (LUTS) but with no evidence of bacterial infection.
PATIENTS AND METHODS
We retrospectively analysed the clinical presentations, pelvic pain and urgency/frequency scores, video‐urodynamic studies, cystoscopy findings, histological features of bladder biopsies and radiological findings of 59 ketamine abusers who were referred to the urology units of Princess Margaret and Tuen Mun Hospital, Hong Kong, from March 2000 to December 2007.
RESULTS
Of the 59 patients, all had moderate to severe LUTS, i.e. frequency, urgency, dysuria, urge incontinence and occasionally painful haematuria. Forty‐two (71%) patients had a cystoscopy that showed various degrees of epithelial inflammation similar to that seen in chronic interstitial cystitis. All of 12 available bladder biopsies had histological features resembling those of interstitial cystitis. Urodynamically, either detrusor overactivity or decreased bladder compliance with or without vesico‐ureteric reflux was detected to some degree in all of 47 patients. Thirty patients (51%) had unilateral or bilateral hydronephrosis on renal ultrasonography, and four (7%) showed features suggestive of papillary necrosis on radiological imaging. Eight patients had a raised serum creatinine level.
CONCLUSION
A syndrome of cystitis and contracted bladder can be associated with street‐ketamine abuse. Secondary renal damage can occur in severe cases which might be irreversible, rendering patients dependent on dialysis. The present data do not establish the precise cause nor the incidence. Street‐ketamine abuse is not only a drug problem, but might be associated with a serious urological condition causing a significant burden to healthcare resources.
Background
Gastrointestinal metabolic surgery has been proposed for the treatment of not well-controlled type 2 diabetes mellitus (T2DM) patients with a body mass index (BMI) <35 kg/m
2
. This study ...aims to describe recent experience with surgical treatment of T2DM in Asian centers.
Methods
Patients aged 20 to 70 years with not well-controlled T2DM glycated hemoglobin (HbA1C) >7.0% and BMI < 35 kg/m
2
were included at five institutes between 2007 and 2010. The end point is T2DM remission, defined by fasting plasma glucose <110 mg/dl and HbA1C <6.0%.
Results
Of the 200 patients, 172 (86%) underwent gastric bypass, 24 (12%) underwent sleeve gastrectomy, and the other 4 underwent adjustable banding. Laparoscopic access was used in all the patients. Gender (66.5% female), age (mean 45.0 ± 10.8), and HbA1C (mean 9.3 ± 1.9%) did not differ between the procedure among the groups. Until now, 87 patients had 1-year data. One year after surgery, the mean BMI decreased from 28.5 ± 3.0 to 23.4 ± 2.3 kg/m
2
and HbA1C decreased to 6.3 ± 0.5%. Remission of T2DM was achieved in 72.4% of the patients. Patients with a diabetes duration of <5 years had a better diabetes remission rate than patients with duration of diabetes >5 years (90.3% vs. 57.1%;
p
= 0.006). Patients with BMI > 30 kg/m
2
had a better diabetes remission rate than those with BMI < 30 kg/m
2
(78.7% vs. 62.5%;
p
= 0.027). Individuals who underwent gastric bypass loss more weight and had a higher diabetes remission rate than individuals who underwent restrictive-type procedures. Multivariate analysis confirmed that the duration of diabetes and the type of surgery predict the diabetes remission. No mortalities were reported and two (1.0%) patients had major morbidities.
Conclusion
Gastrointestinal metabolic surgery is an effective treatment for not well-controlled T2DM treatment. Diabetes remission is significantly higher in those with duration of diabetes less than 5 years and BMI > 30 kg/m
2
.
•A very early study on crack resistance of PSRC members under eccentric tension.•Using CFRP tendons for prestressing SRC members under eccentric tension.•Test data-enhanced analytical method for ...cracking load estimation.•Design formula for estimating the crack resistance.
In recent decades, steel-reinforced concrete (SRC) members under eccentrical tension have been adopted more frequently in modern buildings due to the constraints of more complex structural design/detailing that accompanying contemporary architectural creations. Crack resistance of this type of structures has become a critical design consideration but received insufficient research attention in the past. In this context, the anti-cracking performance of prestressed SRC columns reinforced with CFRP tendons under eccentric tensile loads is investigated experimentally and analytically with the following first-hand experimental validations: 1) prestressed CFRP tendons can well strengthen SRC columns under eccentric tensile load and restrain the crack propagation; 2) an increase in the load eccentricity progressively weakened the influence of prestressing tension level on the cracking load; 3) specimens with the higher prestressed tension level, larger longitudinal reinforcement diameter, and flange thickness exhibited greater crack resistance capacity. Furthermore, the plane-section assumption was also validated in this study. A test data-enhanced analytical method was proposed for determining the cracking load of PSRC columns.
Liver stiffness measurement (LSM) by transient elastography (TE) is a non-invasive assessment for diagnosing and staging liver fibrosis in non-alcoholic fatty liver disease (NAFLD). Evidence on its ...role as a longitudinal monitoring tool is lacking. This study aims to evaluate the role of TE in monitoring NAFLD improvement following bariatric surgery. This study prospectively recruited 101 morbidly obese patients undergoing laparoscopic bariatric surgery for intraoperative liver biopsy. Thirty-seven patients of the cohort received perioperative TE. Postoperative anthropometric, biochemical and LSM data were collected annually for 5 years. In 101 patients receiving liver biopsy (mean age 40.0 ± 10.3 years, mean body-mass-index (BMI) 40.0 ± 5.7 kg/m
), NASH and liver fibrosis were diagnosed in 42 (41.6%) and 48 (47.5%) patients respectively. There were 29 (28.7%) stage 1, 11 (10.9%) stage 2, 7 (6.9%) stage 3, and 1 (1.0%) stage 4 fibrosis. In 37 patients receiving TE (mean age 38.9 ± 10.8 years, mean BMI 41.1 ± 5.6 kg/m
), the percentages of total weight loss were 21.1 ± 7.6% at 1 year, 19.7 ± 8.3% at 3 years, and 17.1 ± 7.0% at 5 years after surgery. The mean LSM reduced significantly from 9.8 ± 4.6 kPa at baseline to 6.9 ± 3.4 kPa at 1 year, 7.3 ± 3.0 kPa at 3 years, and 6.8 ± 2.6 kPa at 5 years (P = 0.002). Using pre-defined LSM cut-offs, the rates of significant fibrosis, advanced fibrosis and cirrhosis being ruled out at 5 years improved from baseline values of 43.7 to 87.5% (P < 0.001), 56.8 to 91.7% (P < 0.001), and 64.9 to 91.7% (P < 0.001), respectively. TE was a useful monitoring tool in demonstrating the improvement of liver fibrosis following bariatric surgery.
We examined trends in accumulated winter chill across the fruit growing region of central California and its internal coastal valleys. We tested the hypothesis that global warming is in motion in ...California and is causing accumulated winter chill to decrease across the fruit and nut growing regions of California. The detection of potential trends in accumulated winter chill (between 0 and 7.2°C) was determined using two complementary climate datasets. The California Irrigation Management Information System (CIMIS) contains hourly climate data and is suitable for computing accumulated chill hours and chill degree-hours. But, its longest data records extend back only to the 1980s. The National Weather Service Coop climate record is longer, extending beyond the 1950s at many sites. But its datasets only contain information on daily maximum and minimum temperatures. To assess long term trends in winter chill accumulation, we developed an algorithm that converted information from daily maximum and minimum temperature into accumulated hours of winter chill and summations of chill-degree hours. These inferred calculations of chill hour accumulation were tested with and validated by direct measurements from hourly-based data from the CIMIS network. With the combined climate datasets, we found that the annual accumulation of winter chill hours and chill degree hours is diminishing across the fruit and nut growing regions of California. Observed trends in winter chill range between -50 and -260 chill hours per decade. We also applied our analytical algorithm to project changes in winter chill using regional climate projections of temperature for three regions in the Central Valley. Predicted rates of reduced winter chill, for the period between 1950 and 2100, are on the order of -40 h per decade. By the end of the 21st century, orchards in California are expected to experience less than 500 chill hours per winter. This chronic and steady reduction in winter chill is expected to have deleterious economic and culinary impact on fruit and nut production in California by the end of the 21st Century.
Purpose
There is a complex association between obesity, hiatal hernia (HH), and reflux. There is a deficiency of literature on the accuracy of preoperative high-resolution manometry (HRM) in ...detecting HH before both primary and revision bariatric surgery.
Materials and Methods
A retrospective analysis of a prospective database of all HRM performed before bariatric surgery from 2014 to 2019. An electronic medical records review was conducted. Sensitivity, specificity, and global diagnostic test accuracy were calculated.
Results
Sixty-seven patients with HRM (mean age of 44.0 ± 11.3 years, body mass index 40.8 ± 6.9 kg/m
2
) were eligible. Intraoperative diagnosis of HH was made in 37 patients (55.2% prevalence). The HRM sensitivity was 48.7% (95% confidence interval (CI) 31.9–65.6%), specificity 90.0% (95% CI 73.5–97.9%), and accuracy was 67.2% (95% CI 54.6–78.2%). Comparing primary (28) and revision (39) surgery, the sensitivity (37.5% vs 57.1%), specificity (75.0% vs 100%), and diagnostic accuracy (54.3% vs 76.3%) were comparable, with overlapping 95% CI. Endoscopy performed in 30 patients had a sensitivity of 25.5% (95% CI 6.8–49.9%), specificity of 100% (95% CI 75.3–100%), and accuracy of 57.8% (95% CI 38.5–75.5%) and was comparable to HRM.
Conclusion
High-resolution manometry for the detection of HH before bariatric surgery has a high specificity and maintains a high accuracy in both primary and revision bariatric surgery.
Graphical abstract
There are increasing concerns about possible malicious modifications of integrated circuits (ICs) used in critical applications. Such attacks are often referred to as hardware Trojans. While many ...techniques focus on hardware Trojan detection during IC testing, it is still possible for attacks to go undetected. Using a combination of new design techniques and new memory technologies, we present a new approach that detects a wide variety of hardware Trojans during IC testing and also during system operation in the field. Our approach can also prevent a wide variety of attacks during synthesis, place-and-route, and fabrication of ICs. It can be applied to any digital system, and can be tuned for both traditional and split-manufacturing methods. We demonstrate its applicability for both application-specified integrated circuits and field-programmable gate arrays. Using fabricated test chips with Trojan emulation capabilities and also using simulations, we demonstrate: 1) the area and power costs of our approach can range between 7.4%-165% and 7%-60%, respectively, depending on the design and the attacks targeted; 2) the speed impact can be minimal (close to 0%); 3) our approach can detect 99.998% of Trojans (emulated using test chips) that do not require detailed knowledge of the design being attacked; 4) our approach can prevent 99.98% of specific attacks (simulated) that utilize detailed knowledge of the design being attacked (e.g., through reverse engineering); and 5) our approach never produces any false positives, i.e., it does not report attacks when the IC operates correctly.
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