Prevalence of All-Cause Mortality and Suicide among Bariatric Surgery Cohorts: A Meta-Analysis.

INTRODUCTION: Prior meta-analysis has reported mortality rates among post-operative bariatric patients, but they have not considered psychiatric factors like suicide contributing to mortality. OBJECTIVES: The current meta-analysis aims to determine the pooled prevalence for mortality and suicide amongst cohorts using reported suicides post bariatric surgery. It is also the aim of the current meta-analytical study to determine moderators that could account for the heterogeneity found. RESULTS: In our study, the pooled prevalence of mortality in the studies which reported suicidal mortality was 1.8% and the prevalence of suicide was 0.3%. Mean body mass index (BMI) and the duration of follow-up appear to be significant moderators. CONCLUSIONS: Given the prevalence of suicide post bariatric surgery, it is highly important for bariatric teams to consider both the medical and psychiatric well-being of individuals pre- and post-operatively.

Selective sorption of uranium from aqueous solution by graphene oxide-modified materials.

The effect of competing ions on the sorption behaviour of uranium onto carboxyl-functionalised graphene oxide (COOH-GO) were studied in batch experiments in comparison to graphene oxide (GO) and graphite. The effect of increasing the abundance of select chemical functional groups, such as carboxyl groups, on the selectivity of U sorption was investigated. In the course of the study, COOH-GO demonstrated superior performance as a sorbent material for the selective removal of uranyl ions from aqueous solution with a distribution coefficient of 3.72 ± 0.19 × 103 mL g-1 in comparison to 3.97 ± 0.5 × 102 and 2.68 ± 0.2 × 102 mL g-1 for GO and graphite, respectively.

Prevalence of Internet Addiction in Medical Students: a Meta-analysis.

OBJECTIVE: With the development of online learning, communication, and entertainment, the Internet has become an indispensable tool for university students. Internet addiction (IA) has emerged as a health problem and the prevalence of IA varies from country to country. To date, the global prevalence of IA in medical students remains unknown. The objective of this meta-analysis was to establish precise estimates of the prevalence of IA among medical students in different countries. METHODS: The pooled prevalence of IA among medical students was determined by the random-effects model. Meta-regression and subgroup analysis were performed to identify potential factors that could contribute to heterogeneity. RESULTS: The pooled prevalence of IA among 3651 medical students is 30.1% (95% confidence interval (CI) 28.5-31.8%, Z = -20.66, df = 9, τ 2 = 0.90) with significant heterogeneity (I 2 = 98.12). Subgroup analysis shows the pooled prevalence of IA diagnosed by the Chen's Internet Addiction Scale (CIAS) (5.2, 95% CI 3.4-8.0%) is significantly lower than Young's Internet Addiction Test (YIAT) (32.2, 95% CI 20.9-45.9%) (p < 0.0001). Meta-regression analyses show that the mean age of medical students, gender proportion and the severity of IA are not significant moderators. CONCLUSIONS: In conclusion, this meta-analysis identified the pooled prevalence of IA among medical students is approximately five times than that of the general population. Age, gender, and severity of IA did not account for high heterogeneity in prevalence, but IA assessment questionnaire was a potential source of heterogeneity. Given the high prevalence of IA, medical teachers and medical school administrators should identify medical students who suffer from IA and refer them for intervention.

Isolation and purification of protactinium-231.

Protactinium-231 is one of the lesser known actinides, yet the measurement of this radionuclide is central to dating studies in both paleoclimate and nuclear forensics measurements; furthermore, it is important as the immediate parent nuclide of the 227Ac decay chain. In this paper, we present the preparatory work for an upcoming CCRI(II) supplementary comparison of this radionuclide. The material used in this work was of poorly known provenance, and it was necessary to carry out a chemical purification of this material prior to use. A new extraction chromatography resin, TK 400, which has been developed for the separation of 231Pa, was tested at NPL. The aims of the work were achieved; the recovery of 231Pa was ~85%, the decay products were recovered in good yield (~95%) and stable element impurities were removed.

The behaviour of 226Ra in high-volume environmental water samples on TK100 resin.

Accurate, low-level measurement of 226Ra in high volume water samples requires rapid pre-concentration and robust separation techniques prior to measurement in order to comply with discharge limits and drinking water regulations. This study characterises the behaviour of 226Ra and interfering elements on recently developed TK100 (Triskem International) extraction chromatography resin. Distribution coefficients over a range of acid concentrations are given, along with an optimised procedure that shows rapid pre-concentration and separation of 226Ra on TK100 resin is achievable for high volume (1 L) water samples without the need for sample pre-treatment.

Evaluation of the separation and purification of 227Th from its decay progeny by anion exchange and extraction chromatography.

Thorium-227 is currently undergoing evaluation as a potential radionuclide for targeted cancer therapy, and as such a high chemical purity of the material is required. To establish a reliable procedure for radiochemical isolation of 227Th from the parent 227Ac and decay progeny, which includes the radiotherapeutic 223Ra, the performance of three different separation schemes based on ion-exchange and extraction chromatography have been evaluated. The results suggest that both ion exchange and extraction chromatographic techniques can be successfully used for the separation of 227Th from its decay progeny, however extraction chromatographic resins demonstrate favourable performance in terms of Th recovery and purification from radionuclide impurities.

Development of a method for rapid analysis of Ra-226 in groundwater and discharge water samples by ICP-QQQ-MS.

A novel and rapid method has been developed for pre-concentration and measurement of 226Ra in groundwater and discharge water samples using the latest generation triple quadrupole inductively coupled plasma mass spectrometry (ICP-QQQ-MS). Cation exchange and extraction chromatography are capable of pre-concentration factors of ~200 based on 1L samples. The sensitivity and interference removal capability of ICP-QQQ-MS was assessed from spiked groundwaters, with the introduction of He collision gas required to minimise instrument background in high-matrix samples. The technique developed is potentially capable of detecting 226Ra activities as low as 5mBqL-1 when combined with pre-concentration prior to measurement.

Reference materials produced for a European metrological research project focussing on measurements of NORM.

Reliable measurement of Naturally Occurring Radioactive Materials is of significance in order to comply with environmental regulations and for radiological protection purposes. This paper discusses the standardisation of three reference materials, namely sand, tuff and TiO2 to serve as quality control materials for traceability, method validation and instrument calibration. The sample preparation, material characterization via γ, α and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the assignment of values for both the 4n (Thorium) and 4n+2 (Uranium) decay series are described.

Transition from Reconstruction toward Thin Film on the (110) Surface of Strontium Titanate.

The surfaces of metal oxides often are reconstructed with a geometry and composition that is considerably different from a simple termination of the bulk. Such structures can also be viewed as ultrathin films, epitaxed on a substrate. Here, the reconstructions of the SrTiO3 (110) surface are studied combining scanning tunneling microscopy (STM), transmission electron diffraction, and X-ray absorption spectroscopy (XAS), and analyzed with density functional theory calculations. Whereas SrTiO3 (110) invariably terminates with an overlayer of titania, with increasing density its structure switches from n × 1 to 2 × n. At the same time the coordination of the Ti atoms changes from a network of corner-sharing tetrahedra to a double layer of edge-shared octahedra with bridging units of octahedrally coordinated strontium. This transition from the n × 1 to 2 × n reconstructions is a transition from a pseudomorphically stabilized tetrahedral network toward an octahedral titania thin film with stress-relief from octahedral strontia units at the surface.

Determination of ¹³5Cs and ¹³7Cs in environmental samples: A review.

Radionuclides of caesium are environmentally important since they are formed as significant high yield fission products ((135)Cs and (137)Cs) and activation products ((134)Cs and (136)Cs) during nuclear fission. They originate from a range of nuclear activities such as weapons testing, nuclear reprocessing and nuclear fuel cycle discharges and nuclear accidents. Whilst (137)Cs, (134)Cs and (136)Cs are routinely measurable at high sensitivity by gamma spectrometry, routine detection of long-lived (135)Cs by radiometric methods is challenging. This measurement is, however, important given its significance in long-term nuclear waste storage and disposal. Furthermore, the (135)Cs/(137)Cs ratio varies with reactor, weapon and fuel type, and accurate measurement of this ratio can therefore be used as a forensic tool in identifying the source(s) of nuclear contamination. The shorter-lived activation products (134)Cs and (136)Cs have a limited application but provide useful early information on fuel irradiation history and have importance in health physics. Detection of (135)Cs (and (137)Cs) is achievable by mass spectrometric techniques; most commonly inductively coupled plasma mass spectrometry (ICP-MS), as well as thermal ionisation (TIMS), accelerator (AMS) and resonance ionisation (RIMS) techniques. The critical issues affecting the accuracy and detection limits achievable by this technique are effective removal of barium to eliminate isobaric interferences arising from (135)Ba and (137)Ba, and elimination of peak tailing of stable (133)Cs on (135)Cs. Isobaric interferences can be removed by chemical separation, most commonly ion exchange chromatography, and/or instrumental separation using an ICP-MS equipped with a reaction cell. The removal of the peak tailing interference is dependent on the instrument used for final measurement. This review summarizes and compares the analytical procedures developed for determination of (135)Cs/(137)Cs, with particular focus on ICP-MS detection and the methods applied to interference separation.

Imprint of monsoonal patterns on the fish assemblage in coastal waters of south-east India: a case study.

The composition, species richness and diversity of a coastal fish assemblage from the Kalpakkam coast of south-east India are described along with temporal distribution patterns related to seasonal fluctuations in dissolved oxygen, salinity, pH, chlorophyll-a, phytoplankton and zooplankton species richness and density. A total of 244 fish species belonging to 21 orders, 87 families and 163 genera were recorded. The fish assemblage was dominated by reef-associated species, followed by demersal species. The majority of the species (63%) are widely distributed in the western Indo-Pacific as well as in the central Indo-Pacific. Jaccard's coefficient analysis showed three distinct seasonal patterns of fish occurrence: pre-monsoon (PrM), monsoon (M) and post-monsoon (PoM). The maximum number of species was during the PrM period, followed by the PoM and M periods. Species occurrence analysis showed Sardinella longiceps to be dominant during PrM and M periods, Leiognathus dussumieri during the M period and Secutor insidiator and Secutor ruconius during the M and PoM periods. Canonical correspondence analysis indicated that salinity and rainfall were the two most influential environmental factors strongly correlated with temporal variation in the fish assemblage. The physico-chemical conditions, in combination with factors such as greater food availability and shelter, might control the seasonal local distribution of the ichthyofauna in these Indian coastal waters.