Enhancement of denitrification by sulfur-based carrier in sequencing batch reactor (SBR) for advanced wastewater treatment

This study was to enhance the nitrogen removal efficiency in the sequencing batch reactor (SBR) process by adding sulfur-based carriers. The nitrogen removal efficiency of the control group was compared with that of the experimental group through a two-series operation of SBR1 without carrier and SBR2 with the carrier under the condition of no external carbon source. A total nitrogen (T-N) removal efficiency of 6.6%, 72.6%, and 79.9% was observed in SBR1, SBR2 (5%), and (10%), respectively. The T-N removal efficiency was improved in the system with carriers, which showed an increase in the removal efficiency of approximately 91.7%. The results suggest that the inclusion of the carrier led to an elevation in the sulfur ratio, implying an augmented surface area for sulfur-based denitrifying microorganisms. Additionally, CaCO3 contributed essential alkalinity for sulfur denitrification, thereby preventing a decline in pH. Regardless of the carrier, the efficiency of organic matter removal surpassed 89%, indicating that the sulfur-based carrier did not adversely affect the biological reaction associated with organic matter. Therefore, autotrophic denitrification was successfully performed using a sulfur carrier in the SBR process without an external carbon source, improving the nitrogen removal efficiency.

Enhancement of fouling resistance of microfiltration membranes by surface modification using UV-curing photopolymer

Membrane fouling, a major problem in membrane-based processes, decreases the water permeability of a membrane. Membrane fouling can be mitigated either by the application of an additional process for membrane cleaning and pretreatment or by fabricating and modifying membranes to achieve low surface interaction forces. This study aimed to improve the fouling resistance of a commercially available membrane by modifying it with a UV-cured photopolymer, MINs, to achieve low surface energy. The morphological variations (thickness and pore size distribution) of the coating layer were most affected by the viscosity of the UV-cured photopolymer. The thickness of the coating layer was inversely proportional to the dilution factor of the MINs. The pore size distribution could be adjusted by surface modification, and the smallest pore size range (0.077-0.078 μm) was observed for the MC5 membrane. In addition, the pore size distribution, surface roughness, and zeta potential of the membrane decreased after the surface modification. Thus, the developed surface modification strategy has potential for improving the fouling resistance of commercially available microfiltration membranes.

A novel approach to measure carbonate alkalinity in aqueous solutions using a total organic carbon analyzer

Carbonate alkalinity is crucial in regulating the pH and buffering capacity of natural water systems. Thus, its accurate measurement is essential to understand various water environments that affect water quality and ecosystem health. However, conventional potentiometric titration has some limitations. It results in inaccurate measurements of carbonate alkalinity when the alkalinity levels are low or when high dissolved organic matter or inorganic ion levels exist. Herein, we propose a novel approach to accurately measure carbonate alkalinity using a total organic carbon (TOC) analyzer. An extensive study comparing the accuracy and reliability of the conventional potentiometric titration method with those of the newly developed TOC method was conducted to develop and verify highly accurate measurements of carbonate alkalinity. The TOC method has several advantages over the conventional potentiometric titration methods, such as its ability to accurately measure carbonate alkalinity in the presence of high dissolved organic matter or inorganic ion levels and its ability to provide rapid and automated measurements with high reproducibility. Because, the limit of detection, limit of quantification, and the variation coefficient of the measurements was 0.016 mM (0.2 mgC/L), 0.050 mM (0.6 mgC/L), and 3.68 % respectively. Thus, the development of a novel TOC method has significant environmental implications as it provides a reliable and accurate means to measure carbonate alkalinity in solutions containing various organic matter types.

Exposure dose and temperature of chlorine on deterioration of thin-film composite membranes for reverse osmosis and nanofiltration

In this study, the effect of chlorine, which is used as a chemical cleaning agent or disinfection agent on membrane deterioration, was analyzed under various conditions during the membrane process. Reverse osmosis (RO: ESPA2-LD and RE4040-BE) and nanofiltration (NF: NE4040-70) membranes made of polyamide (PA) thin film composite (TFC) were used for evaluation. Chlorine exposure was performed at doses ranging from 1000 ppm h to 10,000 ppm h using 10 ppm and 100 ppm, and temperatures from 10 °C to 30 °C. Raw water containing NaCl, MgSO₄, and dextrose was used to compare the filtration performance after exposure to each of the conditions studied. Reduction in removal performance and enhancement in permeability were observed as chlorine exposure increased. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscope (SEM) were employed to determine the surface characteristics of the decomposed membranes. ATR-FTIR was used to compare the intensity of the peaks related to the TFC membrane. Based on the analysis, the state of membrane degradation was elucidated. SEM was used to confirm visual degradation of the membrane surface. Permeability and correlation analyses were performed on CⁿT as an index for determining membrane lifetime in order to investigate the power coefficient. The relative influence of the exposure concentration and time on membrane degradation was explored by comparing the power efficiency according to the exposure dose and temperature.

Status and future trends of hollow fiber biogas separation membrane fabrication and modification techniques

With the increasing global demand for energy, renewable and sustainable biogas has attracted considerable attention. However, the presence of various gases such as methane, carbon dioxide (CO₂), nitrogen, and hydrogen sulfide in biogas, and the potential emission of acid gases, which may adversely influence the environment, limits the efficient application of biogas in many fields. Consequently, researchers have focused on the upgrade and purification of biogas to eliminate impurities and obtain high-quality and high-purity biomethane with an increased combustion efficiency. In this context, the removal of CO₂ gas, which is the most abundant contaminant in biogas, is of significance. Compared to conventional biogas purification processes such as water scrubbing, chemical absorption, pressure swing adsorption, and cryogenic separation, advanced membrane separation technologies are simpler to implement, easier to scale, and incur lower costs. Notably, hollow fiber membranes enhance the gas separation efficiency and decrease costs because their large specific surface area provides a greater range of gas transport. Several reviews have described biogas upgrading technologies and gas separation membranes composed of different materials. In this review, five commonly used commercial biogas upgrading technologies, as well as biological microalgae-based techniques are compared, the advantages and limitations of polymeric and mixed matrix hollow fiber membranes are highlighted, and methods to fabricate and modify hollow fiber membranes are described. This will provide more ideas and methods for future low-cost, large-scale industrial biogas upgrading using membrane technology.

Removal of nitrogen from municipal wastewater by denitrification using a sulfur-based carrier: A pilot-scale study

In the present study, to improve nitrate removal rate, a sulfur-based carrier was applied for autotrophic denitrification, and the removal rate was evaluated for advanced wastewater treatment without adding any external organic carbon source. Based on the results, an increased PAC concentration affected the removal efficiency of NO₃^--N, and the optimal concentration of PAC was at 15 wt%. During the 60 d operation of a pilot process with a capacity of 1 m³/d, the removal of T-N was 81.2% and 50.2% in reactors with and without sulfur-based carrier, respectively. The removal efficiency of NO₃^--N exhibited a similar trend to that of T-N. According to the results, the removal of T-N and NO₃^--N was noticeably enhanced to approximately 30% by adding a sulfur-based carrier to the A₂O pilot system. In addition, microbial community in both reactors was dominated by Thiobacillus, which is an autotrophic microorganism, displaying a dominant denitrification status. The present study compared the relative efficiencies of nitrate removal in A₂O pilot reactors with and without sulfur-based carriers for its successful application in real-scale autotrophic denitrification.

Potential role of fibroblast growth factor 21 in the deterioration of bone quality in impaired glucose tolerance

PURPOSE

Findings on trabecular bone score (TBS), an index of bone quality, have been reported in prediabetes defined by impaired fasting glucose or HbA1c. Here, we assessed the bone mineral density (BMD) and TBS in prediabetes individuals with impaired glucose tolerance (IGT), and investigated the association of these bone parameters with serum levels of fibroblast growth factor 21 (FGF21), a hormone implicated in bone metabolism and with higher levels in IGT.

METHODS

Chinese postmenopausal women aged 55-80 years, without diabetes, were recruited from the Hong Kong Cardiovascular Risk Factor Prevalence Study in 2016-2018. Normal glucose tolerance (NGT) was defined by fasting glucose < 5.6 mmol/L and 2-h plasma glucose (2hG) < 7.8 mmol/L, and IGT by 2hG 7.8-11 mmol/L. Serum levels of FGF21 and other bone metabolism regulators were measured. Insulin sensitivity was assessed by the Matsuda index. Independent determinants of TBS were evaluated using multivariable stepwise linear regression.

RESULTS

173 individuals with NGT and 73 with IGT were included. TBS was lower in those with IGT compared to those with NGT, while BMD was comparable. Individuals with IGT had significantly higher serum FGF21 levels, which in turn showed an independent inverse relationship with TBS, attenuated after inclusion of the Matsuda index. Serum FGF21 levels, however, did not correlate with BMD.

CONCLUSION

Among Chinese postmenopausal women, bone quality was worse in IGT, despite comparable bone density. FGF21 levels showed a significant independent inverse relationship with TBS, partly attributed to insulin resistance. Whether FGF21 contributes to the impaired bone quality in IGT remains speculative.

Energy recovery through reverse electrodialysis: Harnessing the salinity gradient from the flushing of human urine

Urine dilution is often performed to avoid clogging or scaling of pipes, which occurs due to urine's Ca²⁺ and Mg²⁺ precipitating at the alkaline conditions created by ureolysis. The large salinity gradient between urine and flushing water is, theoretically, a source of potential energy which is currently unexploited. As such, this work explored the use of a compact reverse electrodialysis (RED) system to convert the chemical potential energy of urine dilution into electric energy. Urine' composition and ureolysis state as well as solution pumping costs were all taken into account. Despite having almost double its electric conductivity, real hydrolysed urine obtained net energy recoveries E_Net of 0.053-0.039 kWh/m³, which is similar to energy recovered from real fresh urine. The reduced performances of hydrolysed urine were linked to its higher organic fouling potential and possible volatilisation of NH₃ due to its high pH. However, the higher-than-expected performance achieved by fresh urine is possibly due to the fast diffusion of uncharged urea to the freshwater side. Real urine was also tested as a novel electrolyte solution and its performance compared with a conventional K₄Fe(CN)₆/K₃Fe(CN)₆ couple. While K₄Fe(CN)₆/K₃Fe(CN)₆ outperformed urine in terms of power densities and energy recoveries, net chemical reactions seemed to have occurred in urine when used as an electrolyte solution, leading to TOC, ammonia and urea removal of up to 13%, 6% and 4.4%, respectively. Finally, due to the migration of K⁺, NH₄⁺ and PO₄^3-, the low concentration solution could be utilised for fertigation. Overall, this process has the potential of providing off-grid urine treatment or energy production at a household or building level.

HbA1c variability, in addition to mean HbA1c, predicts incident hip fractures in Chinese people with type 2 diabetes

Type 2 diabetes is associated with an increased risk of hip fractures. We hypothesize that long-term glycemic variability predicts incident hip fractures. We demonstrated that HbA1c variability predicted incident hip fractures independent of mean HbA1c, suggesting the potential benefits of minimizing glycemic variability in addition to optimizing mean glycemia for bone health.

INTRODUCTION

Type 2 diabetes is associated with an increased risk of hip fractures, and a linear relationship between HbA1c levels and hip fracture incidence has been observed. We hypothesize that HbA1c variability also predicts incident hip fractures in type 2 diabetes.

METHODS

Chinese individuals with type 2 diabetes aged ≥ 60 years were identified from electronic health records in Hong Kong between 2008 and 2012 and observed for incident hip fractures. Hip fracture was defined by the International Classification of Diseases (Ninth Revision) code 820. HbA1c variability was determined using standard deviation, adjusted standard deviation, and coefficient of variation of HbA1c measurements in the 5 years preceding the entry date. Multivariable Cox regression analysis was used to evaluate associations between HbA1c variability and incident hip fractures.

RESULTS

A total of 83,282 participants were included. Their mean age was 71.3 ± 7.5 years, duration of diabetes 11.7 ± 7.7 years, baseline HbA1c 56.6 ± 13.5 mmol/mol (7.33 ± 1.23%), and median follow-up 6.8 years. All indices of HbA1c variability were significant independent predictors of incident hip fractures, with an adjusted hazard ratio of up to 1.29 (all p < 0.001), and remained to be independent predictors across groups of different intensity of glycemic control. Mean HbA1c ≥ 64 mmol/mol (8.0%) was associated with a 25% increase in incident hip fractures compared with mean HbA1c < 53 mmol/mol (7.0%).

CONCLUSION

HbA1c variability is an independent positive predictor of hip fracture in type 2 diabetes, across the spectrum of varying degree of glycemic control, while a high HbA1c is also not advisable from the perspective of bone health.

Universal haemoglobin A1c screening reveals high prevalence of dysglycaemia in patients undergoing total knee arthroplasty

INTRODUCTION

Diabetes mellitus is an established modifiable risk factor for periprosthetic joint infection (PJI). Haemoglobin A1c (HbA1c) is a glycaemic marker that correlates with diabetic complications and PJI. As diabetes and prediabetes are frequently asymptomatic, and there is increasing evidence to suggest a correlation between dysglycaemia and osteoarthritis, it is reasonable to provide HbA1c screening before total knee arthroplasty (TKA). The aim of the present study was to determine the prevalence of dysglycaemia in patients who underwent TKA and investigate whether HbA1c screening and optimisation of glycaemic control before TKA affects the incidence of PJI after TKA.

METHODS

Patients who underwent primary TKA before and after routine HbA1c screening was introduced in our unit were reviewed. Prediabetes and diabetes were defined according to the American Diabetes Association. Patients with HbA1c ≥7.5% were referred to an endocrinologist for optimisation of glycaemic control before TKA. The incidence PJI, defined according to the Musculoskeletal Infection Society criteria, was recorded.

RESULTS

A total of 729 patients (934 knees) had HbA1c screening before TKA. Of them, 17 (2.3%) and 184 (25.2%) patients had known prediabetes and diabetes, respectively, and 265 (36.4%) and 12 (1.6%) had undiagnosed prediabetes and diabetes, respectively. The incidence of PJI was significantly lower in all patients who received HbA1c screening compared with those who did not (0.2% vs 1.02%, P=0.027).

CONCLUSION

Screening for HbA1c before TKA provides a cost-effective opportunity to identify undiagnosed dysglycaemia. Patients identified as having dysglycaemia receive modified treatment, significantly reducing the rate of PJI when compared with historical controls.

Romosozumab or alendronate for fracture prevention in East Asian patients: a subanalysis of the phase III, randomized ARCH study

Romosozumab, a sclerostin antibody, exerts dual effect to increase bone formation and decrease bone resorption. Among high-risk postmenopausal East Asian women, romosozumab followed by alendronate was associated with lower incidences of fractures vs alendronate alone. Romosozumab demonstrates potential to address an unmet need in osteoporosis management in Asia.

INTRODUCTION

Romosozumab, a sclerostin antibody, exerts dual effect to increase bone formation and decrease bone resorption. The global ARCH study demonstrated superiority of romosozumab followed by alendronate in reducing fracture risk in high-risk postmenopausal osteoporotic women vs alendronate alone. We report outcomes among ARCH East Asian patients.

METHODS

In ARCH, 4093 postmenopausal osteoporotic women with fragility fracture were randomized 1:1 to monthly romosozumab 210 mg or weekly alendronate 70 mg for 12 months, both followed by open-label alendronate. Primary endpoints were incidence of new vertebral fracture (VF) at 24 months and clinical fracture at primary analysis (confirmed fractures in ≥ 330 patients and all patients had opportunity to attend month 24 visit). This post hoc analysis was not powered to detect fracture-rate differences.

RESULTS

This analysis included 275 patients from Hong Kong, Korea, and Taiwan. Romosozumab followed by alendronate reduced risk of new VFs at 24 months by 60% (P = 0.11) and clinical fractures at primary analysis by 44% (P = 0.15) vs alendronate alone. Romosozumab followed by alendronate significantly increased mean bone mineral density at 24 months from baseline by a further 9.0%, 3.3%, and 3.0% at the lumbar spine, total hip, and femoral neck vs alendronate alone. Adverse event (AE) rates, including positively adjudicated serious cardiovascular AEs (1.6% vs 1.4% at 12 months for romosozumab vs alendronate), were similar across treatment groups.

CONCLUSIONS

Consistent with the global analysis, romosozumab followed by alendronate was associated with lower incidences of new vertebral, clinical, non-vertebral, and hip fractures vs alendronate alone among East Asian patients.

A clinical prediction score using age at diagnosis and saline infusion test parameters can predict aldosterone-producing adenoma from idiopathic adrenal hyperplasia

PURPOSE

Accurate subtyping of the primary aldosteronism into aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH) is important to direct for specific treatment modalities. The objective of the study was to compare the clinical and biochemical parameters of APA and IAH patients to derive a Clinical Prediction Score reliably predicting APA from IAH.

METHODS

This was a retrospective multi-centre study recruiting 38 APA patients and 42 IAH patients from four major hospitals in Hong Kong using database from Surgical Outcomes Monitoring and Improvement Programme and Clinical Data Analysis and Reporting System. Their clinical and biochemical parameters were evaluated.

RESULTS

Patients in APA group were younger than IAH group (mean age 48.6 ± 9.2 vs. 57.1 ± 7.3 years old, p < 0.001), had more suppressed renin before saline infusion in saline infusion test (SIT) (median 0.19 [IQR 0.15-0.37] vs. 0.39 [IQR 0.19-0.69] ng/mL/h, p = 0.01), and higher aldosterone level after saline infusion in SIT (median 674 [IQR 498-1000] vs. 327 [IQR 242-483] pmol/L, p < 0.001). A clinical prediction score using three parameters was devised, comprising age at diagnosis < 50 years, PRA before saline infusion in SIT ≤ 0.26 ng/mL/h, and aldosterone level after saline infusion in SIT ≥ 424 pmol/L. A score of 2 would predict APA with a sensitivity of 84.2% and specificity of 88.1%, and a score of 3 would predict APA with a sensitivity of 31.6% and specificity of 100%.

CONCLUSIONS

Clinical Prediction Score based on the combination of age at diagnosis, PRA, and aldosterone level in the saline infusion tests could reliably predict APA from IAH.

Reverse osmosis membrane fabrication and modification technologies and future trends: A review

Reverse osmosis (RO) is the most widely used technology in water treatment and desalination technologies for potable water production. Since its invention, RO has undergone significant developments in terms of material science, process, system optimization, methods of membrane synthesis, and modifications. Among various materials used for the synthesis of an RO membrane, the polyamide thin-film composite (PA-TFC) is by far the most common, owing to its excellent water permeability high salt rejection, and stability. However, a tradeoff between membrane permeability and salt rejection and membrane fouling has been a major hindrance for the effective application of this membrane. Thus, a broad investigation has been carried out to address these problems, and among which co-solvent interfacial polymerization (CAIP) and the surface modification of substrates and active layers of RO membrane have been the most effective approaches for controlling and improving the surface properties of the PA-TFC membrane. In this review paper, the problems associated with the RO membrane processes and strategies has been discussed and addressed in detail. Furthermore, as the focus of this review, the major advancements in the strategies used for enhancement of RO membrane performance through CAIP, and surface modifications were scrutinized and summarized.

A pilot study of spiral-wound air gap membrane distillation process and its energy efficiency analysis

Brine disposal is a major drawback for seawater desalination. Membrane distillation (MD) is an emerging technology to treat a high saline water including brine disposal instead of reverse osmosis, multi-stage flash and multi-effect distillation. This study investigated a pilot scale of a spiral-wound air gap MD (AGMD) module and evaluated its efficiency. A pilot-scale AGMD module with design production capacity of 10 m³/d was operated. Experiments with varying flow velocity showed increasing trend of water vapor flux as flow velocity increases. The temperature is one of the significant points in maximizing water permeate vapor flux in MD. Increasing temperature from 65 °C to 75 °C in evaporator channel has increased flux from 0.59 to 1.15 L/m²/h. Under various conditions, specific thermal energy consumption (STEC) and gained output ratio (GOR) was used to analyze energy efficiency. The pilot plant showed high GOR value in spite of a limited heating and cooling source available at the site. The highest GOR achieved was 3.54 with STEC of 182.78 kWh/m³. This study provides an overview of operation experience and its data analysis related to temperature, concentration, flow rate and energy supply.

Membrane-based technologies for zero liquid discharge and fluoride removal from industrial wastewater

Several defluoridation techniques for reducing high initial fluoride concentration (IFC) in wastewater have been tested, but only a few of them have achieved the permissible standards. This study examined the hybrid crystallization-reverse osmosis technique (HRO) in light of flux, fluoride removal efficiency, fouling tendency, mineral recovery, complying zero liquid discharge (ZLD), and effluent discharge standard (EDS). Simulated wastewater with an IFC of 6600 mg/L was utilized and the final HRO performance was compared with those of the low-pressure (30 bar) standalone reverse osmosis (SRO), nanofiltration (SNF), and membrane distillation (SMD) processes. Accordingly, the study on SRO and SNF revealed that pressure, feed pH, membrane type, and IFC were the major factors affecting performance, and SRO was unable to sufficiently defluoridate wastewater with IFC >614 mg/L, needing pretreatment. Subsequently, the HRO process was selected and it was seen that the optimum calcium dose and respective final effluent pH for attaining EDS and ZLD were 16.5 g/L & 7.1 and 19.8 g/L & 5.7 respectively. The best operating pH for all conditions in HRO was approximately 9. Additionally, HRO showed good mineral recovery tendency and less organic fouling. The overall comparisons of flux and residual fluoride for HRO, SRO, SNF, and SMD were 49.3 LMH & 1.21 mg/L; 34.9 LMH & 62 mg/L, 44.05 LMH & 301 mg/L, and 38 LMH & 0.9 mg/L respectively. Therefore, low-pressure HRO can be applied to treat wastewater with high IFC; good tendency of mineral recovery, as good as that of SMD.

Analysis of mass transfer behavior in membrane distillation: Mathematical modeling under various conditions

Four commercially available hydrophobic membranes with different pore sizes were separately used in a direct contact membrane distillation (DCMD) apparatus to investigate the effect of fouling on the mass transfer coefficient, and the dominant mass transport mode under different conditions defined by the temperature, membrane material, flow regime, and membrane pore size. Both ultrapure deionized water and simulated industrial wastewater were considered as the feed water. The results of the investigation confirmed that the fouling layer impacted the mass transport directly by resisting it, and indirectly by altering the heat transfer mechanism. In addition to the surface fouling layer, a significant number of particles were also observed to accumulate in the membrane pores. It was further determined that the contribution of Poiseuille flow to the entire mass transport was significant at higher temperatures when using a membrane with large pores. This highlighted the need for careful consideration of Poiseuille flow in the modeling and simulation of a membrane distillation (MD) mass transport process. It was also observed that the flow rate did not affect the Poiseuille flow and therefore did not directly impact the entire mass transfer. The study findings provide systematic insight for the development of a strategy for selecting an appropriate operating feed for DCMD and adjusting the permeate temperature to fit the prevailing water demand and environmental conditions.

Removal of fluoride in membrane-based water and wastewater treatment technologies: Performance review

The presence of excess fluoride in aqueous media above local environmental standards (e.g., the U.S. Environmental Protection Agency (EPA) standard of 4 mg/L) affects the health of aquatic life. Excess fluoride in drinking water above the maximum contaminant level (e.g., the World Health Organization (WHO) standard of 1.5 mg/L) also affects the skeletal and nervous systems of humans. Fluoride removal from aqueous solutions is difficult using conventional electrochemical, precipitation, and adsorption methods owing to its ionic size and reactivity. Thus, new technologies have been introduced to reduce the fluoride concentration in industrial wastewater effluents and various drinking water sources. Membrane technology is one of the newer technologies found to be very effective in significantly reducing fluoride to desired standards levels; however, it has received less attention than other technologies because it is perceived as a costly process. This study critically reviewed the performance of various membrane process and compared it with effluent and zero liquid discharge (ZLD) standards. The performance review has been conducted with the consideration of the theoretical background, rejection mechanisms, technical viability, and parameters affecting flux and rejection performance. This review includes membrane systems investigated for the defluoridation process but operated under pressure (i.e., reverse osmosis [RO] and nanofiltration [NF]), temperature gradients (i.e., membrane distillation [MD]), electrical potential gradients (i.e., electrodialysis [ED] and Donnan dialysis [DD]), and concentration differences (i.e., forward osmosis [FO]). Moreover, the study also addressed the advantages, limitations, & applicable conditions of each membrane based defluoridation process.

Nanoscale zero-valent iron (nZVI) immobilization onto graphene oxide (GO)-incorporated electrospun polyvinylidene fluoride (PVDF) nanofiber membrane for groundwater remediation via gravity-driven membrane filtration

Nanoscale zero-valent iron (nZVI), with its high reactivity towards a broad range of contaminants, has been a promising material for groundwater remediation. Membrane-supported nZVI can both avoid nZVI agglomeration for better reactivity and recycle nZVI to lower the risk of secondary pollution. In this study, we successfully fabricated a PVDF-GO membrane via electrospinning technology and employed the functionalized nanofiber membrane to immobilize nZVI particles. The addition of GO into PVDF nanofibers can both increase the hydrophilicity to improve membrane flux and offer -COOH as a binder to immobilize nZVI particles. PVDF-GO-nZVI membranes with different GO loadings (0%, 0.5%, 1%, 3% of PVDF) were tested with two typical nZVI-targeted contaminants (Cd(II) and trichloroethylene (TCE)) via gravity-driven membrane filtration. The results show that membrane with 1% GO had the best nZVI distribution against the aggregation and a better performance in both Cd removal (100%) and TCE removal (82%). The nZVI membrane had a high flux in gravity-driven filtration at 255 LMH for Cd(II) and 265 LMH for TCE respectively. Generally, the developed PVDF-GO-nZVI electrospun nanofiber membrane had an excellent performance in the gravity-driven membrane filtration system for groundwater remediation.

Improving membrane distillation performance: Morphology optimization of hollow fiber membranes with selected non-solvent in dope solution

This study aimed at improving membrane distillation (MD) performance by mixing various non-solvents (NSs) in polymer dope solutions. The effect of each NS on the inner structure and surface morphology of hollow fiber (HF) membrane was investigated. Membrane morphology is manipulated by controlling liquid-liquid (L-L) and solid-liquid (S-L) demixing time, which is a function of the viscosity and water affinity of dope solutions. Consequently, the addition of NSs altered membrane morphology by affecting the diffusion rate during NS induced phase separation (NIPS) process. The performance results showed that the dope solution composed of 11/71.2/17.8 wt% polyvinylidene fluoride (PVDF)/triethyl phosphate (TEP)/toluene produced the most promising HF membrane for MD. The optimal membrane demonstrated a unique bicontinuous structure with increased porosity and mean pore size. The addition of toluene as NS in dope solutions enhanced crystallization process, which increased the Young's modulus of membrane but slightly decreased its maximum tensile strength at break. The optimal PVDF HF membrane demonstrated a steady flux of 18.9 LMH at 60 °C/20 °C of feed/permeate temperatures and a salt rejection of 99.99% when tested for 72 h. The results suggest that incorporation of toluene as a NS into PVDF dope solutions can increase permeation performance in MD by enhancing the morphology of HF membranes.

Volatile fatty acids and biogas recovery using thermophilic anaerobic membrane distillation bioreactor for wastewater reclamation

The effects of bioreactor temperatures and salinities of an anaerobic membrane distillation bioreactor (anMDBR) on the permeation performance and their potential recovery of bioresources were fully examined in this study. To the best of our knowledge, this is the first study of a lab-scale anMDBR process utilizing sub-merged hollow fiber membranes. The hybrid system utilizing both membrane distillation (MD) and anaerobic bioreactors achieved 99.99% inorganic salt rejection regardless the operation temperatures and high initial flux from (2-4 L m^-2 h^-1) at 45-65 °C. However, after 7-day operation, the flux dropped by 16-50% proportional to the bioreactor temperatures. It was found that the effects of bioreactor temperatures had strong impacts on both the permeation performance and fouling behavior while salinity had insignificant effect. A compact non-porous fouling layer was observed on the membrane surface from the bioreactor operated at 65 °C while only a few depositions was found on the membrane from 45 °C bioreactor. In the present study, the optimal anMDBR temperature was found to be 45 °C, showing a balanced biogas production and membrane permeation performance including less fouling formation. At this bioreactor temperature (45 °C), the biogas yield was 0.14 L/g COD_removal, while maintaining a methane recovery of 42% in the biogas, similar recovery to those at bioreactor temperatures of 55 and 65 °C. The potential recovery of volatile fatty acids made anMDBR a more economically efficient system, in addition to its lower operation cost and smaller footprint compared with most other technologies for on-site wastewater treatment.

Core-Shell Interface-Oriented Synthesis of Bowl-Structured Hollow Silica Nanospheres Using Self-Assembled ABC Triblock Copolymeric Micelles

Hollow porous silica nanospheres (HSNs) are emerging classes of cutting-edge nanostructured materials. They have elicited much interest as carriers of active molecule delivery due to their amorphous chemical structure, nontoxic nature, and biocompatibility. Structural development with hierarchical morphology is mostly required to obtain the desired performance. In this context, large through-holes or pore openings on shells are desired so that the postsynthesis loading of active-molecule onto HSNs via a simple immersion method can be facilitated. This study reports the synthesis of HSNs with large through-holes or pore openings on shells, which are subsequently termed bowl-structured hollow porous silica nanospheres (BHSNs). The synthesis of BHSNs was mediated by the core-shell interfaces of the core-shell corona-structured micelles obtained from a commercially available ABC triblock copolymer (polystyrene- b-poly(2-vinylpyridine)- b-poly(ethylene oxide) (PS-P2VP-PEO)). In this synthesis process, polymer@SiO₂ composite structure was formed because of the deposition of silica (SiO₂) on the micelles' core. The P2VP block played a significant role in the hydrolysis and condensation of the silica precursor, i.e., tetraethylorthosilicate (TEOS) and then maintaining the shell's growth. The PS core of the micelles built the void spaces. Transmission electron microscopy (TEM) images revealed a spherical hollow structure with an average particle size of 41.87 ± 3.28 nm. The average diameter of void spaces was 21.71 ± 1.22 nm, and the shell thickness was 10.17 ± 1.68 nm. According to the TEM image analysis, the average large pore was determined to be 15.95 nm. Scanning electron microscopy (SEM) images further confirmed the presence of large single pores or openings in shells. These were formed as a result of the accumulated ethanol on the PS core acting to prevent the growth of silica.

Membrane distillation for industrial wastewater treatment: Studying the effects of membrane parameters on the wetting performance

Substantial amounts of trace hazardous elements have been detected in industrial wastewater (e.g fluoride > 900 mg/L). Feed water characteristics, operational parameters, and membrane properties are major factors affecting flux and rejection of the MD process. Membrane parameters such as membrane material type and pore size have been investigated. Fluoride ion rejection was selected to setup a methodology to remove trace elements from wastewater by adjusting the membrane parameters in DCMD. Study of the fouling thickness of the MD membrane using pH and feed water composition revealed that a PVDF membrane with a smooth surface holds a thicker fouling layer, which enhances fluoride rejection while reducing the permeate flux. On the other hand, PTFE and PP membranes showed higher mass transfer and higher wetting performance, respectively. Therefore,a PVDF membrane with low organic feed water at higher alkaline pH can be utilized to obtain high-quality permeate, while PTFE can provide the highest flux with acceptable permeate water quality. Therefore, this methodology can be applied toidentify the optimum membrane to fit the required permeate flux, rejection requirements,and operating pH to treat any kind of non-volatileinorganic pollutants from industrial wastewater.

Measurement properties of ThyPRO short-form (ThyPRO-39) for use in Chinese patients with benign thyroid diseases

PURPOSE

To evaluate the validity and reliability of a newly-translated Thyroid-specific Patient-Reported Outcome short-form (ThyPRO-39) instrument for ethnic-Chinese patients suffering from benign thyroid diseases.

METHODS

The translation and cross-cultural adaptation of the English ThyPRO-39 were performed using the double forward translation, reconciliation, single backward translation, and cognitive debriefing, followed by a panel review. Cross-sectional data of 308 patients with benign thyroid diseases were utilized for this psychometric evaluation of ThyPRO-39 instrument. Convergent validity between similar construct in the ThyPRO-39, SF-6D, and SF-12v2 was assessed using Spearman correlations. The internal construct validity was assessed by corrected item-total correlations. Sensitivity of the ThyPRO-39 domain scores was determined by performing known group comparisons by independent t test. The internal consistency reliability was assessed by Cronbach's alpha coefficient.

RESULTS

Significant floor effects were observed in 9 out of 13 domains of the ThyPRO-39. The hypothesized correlations between similar constructs in the ThyPRO-39 and the SF-12v2 and SF-6D were generally observed, supporting convergent validity. The internal construct validity was supported in most items, except eight items in six scales. Scale score of hyperthyroid symptoms of the ThyPRO-39 was significantly higher in the group with Graves' disease or hyperthyroid disease than the group without Graves' disease nor hyperthyroid disease. Scale scores of eye symptoms and impaired daily life were significantly higher in the incidental group than the non-incidental group. For six domains (hyperthyroid symptoms, hypothyroid symptoms, eye symptoms, tiredness, depressivity, and emotional susceptibility), Cronbach's alpha did not reach the recommended standard of 0.7.

CONCLUSIONS

This was the first psychometric study to translate and adapt the ThyPRO-39 instrument for non-Caucasian patients, and report its validity and reliability for use in Chinese patients with benign thyroid diseases. Given the low item-total correlations in eight items and low internal consistency reliability in respective scales of the ThyPRO-39, we suggest that the improvement of those eight items should produce a more valid and reliable ThyPRO-39 instrument.

Hierarchical Composite Membranes with Robust Omniphobic Surface Using Layer-By-Layer Assembly Technique

In this study, composite membranes were fabricated via layer-by-layer (LBL) assembly of negatively charged silica aerogel (SiA) and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FTCS) on a polyvinylidene fluoride phase inversion membrane and interconnecting them with positively charged poly(diallyldimethylammonium chloride) (PDDA) via electrostatic interaction. The results showed that the PDDA-SiA-FTCS coated membrane had significantly enhanced the membrane structure and properties. New trifluoromethyl and tetrafluoroethylene bonds appeared at the surface of the coated membrane, which led to lower surface free energy of the composite membrane. Additionally, the LBL membrane showed increased surface roughness. The improved structure and property gave the LBL membrane an omniphobic property, as indicated by its good wetting resistance. The membrane performed a stable air gap membrane distillation (AGMD) flux of 11.22 L/m² h with very high salt rejection using reverse osmosis brine from coal seam gas produced water as feed with the addition of up to 0.5 mM SDS solution. This performance was much better compared to those of the neat membrane. The present study suggests that the enhanced membrane properties with good omniphobicity via LBL assembly make the porous membranes suitable for long-term AGMD operation with stable permeation flux when treating challenging saline wastewater containing low surface tension organic contaminants.

Anti-fouling graphene-based membranes for effective water desalination

The inability of membranes to handle a wide spectrum of pollutants is an important unsolved problem for water treatment. Here we demonstrate water desalination via a membrane distillation process using a graphene membrane where water permeation is enabled by nanochannels of multilayer, mismatched, partially overlapping graphene grains. Graphene films derived from renewable oil exhibit significantly superior retention of water vapour flux and salt rejection rates, and a superior antifouling capability under a mixture of saline water containing contaminants such as oils and surfactants, compared to commercial distillation membranes. Moreover, real-world applicability of our membrane is demonstrated by processing sea water from Sydney Harbour over 72 h with macroscale membrane size of 4 cm², processing ~0.5 L per day. Numerical simulations show that the channels between the mismatched grains serve as an effective water permeation route. Our research will pave the way for large-scale graphene-based antifouling membranes for diverse water treatment applications.

Intrinsic limitations of nanoporous graphene limit its applications in water treatment. Here the authors produce post-treatment-free, low-cost graphene-based membranes from renewable biomass and demonstrate their high water permeance and antifouling properties using real seawater.

Effective Dose of Remifentanil for Control of Haemodynamic Response to Insertion of the Streamlined Liner of the Pharyngeal Airway

Objective

To determine the dose of remifentanil needed to achieve successful insertion of the Streamlined Liner of the Pharyngeal Airway (SLIPA™) without the development of hypertension in 95% of the patients.

Design

Randomised controlled trial.

Setting

operating theatre of a university hospital

Methods

A total of 100 ASA I or II patients requiring SLIPA insertion were randomly assigned to receive normal saline (Group C) or one of the four different doses (0.5 µg/kg [Group R0.5], 1.0 µg/kg [Group R1], 1.5 µg/kg [Group R1.5] or 2.0 µg/kg [Group R2]) of remifentanil. Arterial blood pressure and heart rate were recorded at preanesthetic baseline, preinserton, and every one minute during the initial 3 minutes period after insertion.

Results

A Probit model of remifentanil concentration was predictive of successful insertion of SLIPA without the development of hypertension. The ED95 of remifentanil needed to suppress haemodynamic response from SLIPA insertion was 1.39 µg/kg (95% confidence interval, 1.06-2.61 µg/kg).

Conclusions

A single administration of remifentanil can effectively suppress haemodynamic changes due to the insertion of SLIPA.

Streamlined Liner of the Pharynx Airway: Randomised Comparison of Size Selection Strategies with Regard to Patient Height versus Thyroid Cartilage Width

Introduction

Streamlined Liner of the Pharynx Airway (SLIPA) is a disposable supraglottic airway. There are two strategies to select the size of SLIPA: by height and width of thyroid cartilage. This study compared the utility of the two strategies in selecting the optimal size.

Methods

One hundred forty-two patients were randomly divided into two groups with size selection by height (H) and the maximal width of the thyroid cartilage (T). The SLIPA size was selected by height in group H, and by the width of thyroid cartilage in group T. After inserting SLIPA, the investigator made note of the oropharyngeal leakage pressure (OLP) and the degree of insertion difficulty. We set the OLP as a primary outcome. In cases of an OLP <15 cmH2O, the investigator manipulated the apparatus to try to reposition it. If air still leaked, another attempt was made using a SLIPA one size larger until an OLP >15 cmH2O was achieved in up to three attempts. After insertion, the investigator measured the inspiratory and expiratory tidal volume. Post-operatively, the presence of blood or regurgitated fluid on the device was evaluated.

Results

OLP for group T was higher than that of group H (p=0.009). The need for manipulation and the leak fraction was higher in group H than in group T (p=0.008 and 0.034, respectively). The degree of insertion difficulty, number of trials and incidence of blood and regurgitated fluid on the device were similar between the two groups.

Conclusions

Both the width and height of thyroid cartilage can be used for selecting the optimal SLIPA size. (Hong Kong j.emerg.med. 2015;22:303-311)

Engineering the Re-Entrant Hierarchy and Surface Energy of PDMS-PVDF Membrane for Membrane Distillation Using a Facile and Benign Microsphere Coating

To consolidate the position of membrane distillation (MD) as an emerging membrane technology that meets global water challenges, it is crucial to develop membranes with ideal material properties. This study reports a facile approach for a polyvinylidene fluoride (PVDF) membrane surface modification that is achieved through the coating of the surface with poly(dimethylsiloxane) (PDMS) polymeric microspheres to lower the membrane surface energy. The hierarchical surface of the microspheres was built without any assistance of a nano/microcomposite by combining the rapid evaporation of tetrahydrofuran (THF) and the phase separation from condensed water vapor. The fabricated membrane exhibited superhydrophobicity-a high contact angle of 156.9° and a low contact-angle hysteresis of 11.3°-and a high wetting resistance to seawater containing sodium dodecyl sulfate (SDS). Compared with the control PVDF-hexafluoropropylene (HFP) single-layer nanofiber membrane, the proposed fabricated membrane with the polymeric microsphere layer showed a smaller pore size and higher liquid entry pressure (LEP). When it was tested for the direct-contact MD (DCMD) in terms of the desalination of seawater (3.5% of NaCl) containing SDS of a progressively increased concentration, the fabricated membrane showed stable desalination and partial wetting for the 0.1 and 0.2 mM SDS, respectively.

Which creatinine-based estimated glomerular filtration rate equation best predicts all-cause mortality in Chinese subjects with type 2 diabetes?

AIM

In Chinese, ethnicity-based and/or diabetes specific modifications of the Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations have been developed for determining estimated glomerular filtrate rate (eGFR). This study aimed to compare the performance of five different creatinine-based eGFR equations in predicting all-cause mortality among Chinese subjects with type 2 diabetes (T2DM).

METHODS

A total of 6739 Chinese subjects with T2DM were included. Their eGFR was calculated using the MDRD, CKD-EPI, their respective modified equations for Chinese, and the diabetes specific CKD-EPI Chinese T2DM equations. Multiple Cox regression analysis was used to evaluate the associations of eGFR with all-cause mortality. C-statistics, net reclassification index (NRI) and integrated discrimination index (IDI) were applied to assess the discrimination and reclassification of each eGFR equation in predicting mortality outcome.

RESULTS

Over a follow-up of 5.7years, the incidence of all-cause mortality was 12.9% (N=867). The CKD-EPI equation discriminated all-cause mortality better than the MDRD equation (C-statistics: 0.714 vs. 0.689, p<0.0001), and Chinese modification of their respective equations did not improve discrimination. Among the five eGFR equations evaluated, the CKD-EPI Chinese T2DM equation provided the best discrimination in predicting all-cause mortality among Chinese subjects with T2DM, and was the only equation providing a significantly positive NRI and IDI relative to the CKD-EPI equation.

CONCLUSIONS

Among Chinese subjects with T2DM, our findings suggested that the CKD-EPI Chinese T2DM equation best predicted all-cause mortality, and relative to the CKD-EPI equation, conferred improved discrimination and reclassification.

Effect of powdered activated carbon on integrated submerged membrane bioreactor-nanofiltration process for wastewater reclamation

The aim of this study was to determine the effect of powdered activated carbon (PAC) on the overall performance of a submerged membrane bioreactor (SMBR) system integrated with nanofiltration (NF) for wastewater reclamation. It was found that the trans-membrane pressure of SMBR increased continuously while that of the SMBR with PAC was more stable, mainly because water could still pass through the PACs and membrane even though foulants adhered on the PAC surface. The presence of PAC was able to mitigate fouling in SMBR as well as in NF. SMBR-NF with PAC obtained a higher flux of 8.1 LMH compared to that without PAC (6.6 LMH). In addition, better permeate quality was obtained with SMBR-NF integrated process added with PAC. The present results suggest that the addition of PAC in integrated SMBR-NF process could possibly lead to satisfying water quality and can be operated for a long-term duration.

Genetics of Apparently Sporadic Pheochromocytoma and Paraganglioma in a Chinese Population

Identification of germline mutation in patients with apparently sporadic pheochromocytomas and paragangliomas is crucial. Clinical indicators, which include young age, bilateral or multifocal, extra-adrenal, malignant, or recurrent tumors, predict the likelihood of harboring germline mutation in Caucasian subjects. However, data on the prevalence of germline mutation, as well as the applicability of these clinical indicators in Chinese, are lacking. We conducted a cross-sectional study at a single endocrine tertiary referral center in Hong Kong. Subjects with pheochromocytomas and paragangliomas were evaluated for the presence of germline mutations involving 10 susceptibility genes, which included NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, TMEM 127, MAX, and FH genes. Clinical indicators were assessed for their association with the presence of germline mutations. Germline mutations, 2 being novel, were found in 24.4% of the 41 Chinese subjects recruited and 11.4% among those with apparently sporadic presentation. The increasing number of the afore-mentioned clinical indicators significantly correlated with the likelihood of harboring germline mutation in one of the 10 susceptibility genes. (r=0.757, p=0.026). The presence of 2 or more clinical indicators should prompt genetic testing for germline mutations in Chinese subjects. In conclusion, our study confirmed that a significant proportion of Chinese subjects with apparently sporadic pheochromocytoma and paraganglioma harbored germline mutations and these clinical indicators identified from Caucasians series were also applicable in Chinese subjects. This information will be of clinical relevance in the design of appropriate genetic screening strategies in Chinese populations.

Cardiometabolic risk profile of participants with prediabetes diagnosed by HbA1c criteria in an urban Hong Kong Chinese population over 40 years of age

AIMS

To investigate the usefulness of the additional measurement of HbA1c , compared with performing only the oral glucose tolerance test (OGTT), in identifying participants at increased cardiometabolic risk, in an urban Chinese population.

METHODS

All participants from the fourth visit of the population-based Hong Kong Cardiovascular Risk Factors Prevalence Study, without known diabetes, were included. All had their glycaemic status assessed by OGTT and HbA1c , according to American Diabetic Association 2010 criteria.

RESULTS

Based on OGTT criteria alone, 3.5% of the study cohort (N = 1300) had diabetes and 19.2% had prediabetes. Based on HbA1c criteria only, 6.2% had diabetes and 61.2% had prediabetes. The measurement of HbA1c , in addition to the OGTT, increased the proportion of participants with diabetes to 7.8% and with prediabetes to 65.3%. Subjects with prediabetes having raised HbA1c but normal glycaemia (N = 600) had waist circumference, systolic blood pressure, fasting glucose, insulin resistance index (HOMA-IR), Gutt Index and Framingham 10-year cardiovascular risk scores intermediate between those with both normal HbA1c and glycaemia (N = 350), and those with impaired fasting glucose and/or impaired glucose tolerance (N = 249; all P < 0.01).

CONCLUSION

The measurement of HbA1c in our population, in addition to the OGTT, results in the detection of a large number of participants with prediabetes having raised HbA1c but normal glycaemia who have a cardiometabolic risk profile intermediate between impaired fasting glucose and/or impaired glucose tolerance and normal participants, and would benefit from early lifestyle intervention.

Obesity, adipokines and cancer: an update

Obesity causes dysfunction of adipose tissue, with resultant chronic inflammation and adverse interplay of various adipokines, sex steroids and endocrine hormones. All these drive tumourigenesis and explain the epidemiological link between obesity and cancer. Over the past decade, the associations among obesity, adipokines and cancer have been increasingly recognized. Adipokines and their respective signalling pathways have drawn much research attention in the field of oncology and cancer therapeutics. This review will discuss the recent advances in the understanding of the association of several adipokines with common obesity-related cancers and the clinical therapeutic implications.

Circulating fibroblast growth factor 21 levels predict progressive kidney disease in subjects with type 2 diabetes and normoalbuminuria

BACKGROUND

Elevated fibroblast growth factor 21 (FGF21) levels have been suggested, from cross-sectional studies, as an indicator of subclinical diabetic nephropathy. We investigated whether serum FGF21 was predictive of the development of diabetic nephropathy.

METHOD

Baseline serum FGF21 levels were measured in 1136 Chinese type 2 diabetic subjects recruited from the Hong Kong West Diabetes Registry. The role of serum FGF21 in predicting decline in estimated glomerular filtration rate (eGFR) over a median follow-up of 4 years was analyzed using Cox regression analysis.

RESULTS

At baseline, serum FGF21 levels increased progressively with eGFR category (P for trend <.001). Among 1071 subjects with baseline eGFR ≥ 30 mL/min/1.73 m(2), serum FGF21 levels were significantly higher in those with eGFR decline during follow-up (n = 171) than those without decline (n = 900) (P < .001). In multivariable Cox regression analysis, baseline serum FGF21 was independently associated with eGFR decline (hazard ratio, 1.21; 95% confidence interval [CI], 1.01-1.43; P = .036), even after adjustment for baseline eGFR. In a subgroup of 559 subjects with baseline eGFR ≥ 60 mL/min/1.73 m(2) and normoalbuminuria, serum FGF21 level remained an independent predictor of eGFR decline (hazard ratio, 1.36; 95% CI, 1.06-1.76; P = .016). Integrated discrimination improvement (IDI) suggested that the inclusion of baseline serum FGF21 significantly improved the prediction of eGFR decline (IDI, 1%; 95% CI, 0.1-3.0; P = .013) in this subgroup, but not in the initial cohort involving all subjects.

CONCLUSIONS

Elevated serum FGF21 levels may be a useful biomarker for predicting kidney disease progression, especially in the early stages of diabetic nephropathy.

Comparison of streamlined liner of the pharynx airway (SLIPA ™) and laryngeal mask airway: a systematic review and meta-analysis

We performed a systematic review to compare the efficacy and safety of the streamlined liner of the pharynx airway and laryngeal mask airway used in adults during general anaesthesia. We included 14 studies with studies with 1273 patients in total. There was no evidence of a difference between the two devices in insertion success rate on the first attempt (13 studies, 1143 patients), insertion time (seven studies, 576 patients), ease of insertion (five studies, 466 patients), oropharyngeal leak pressure (eight studies, 771 patients) and the quality of the fibreoptic view of the larynx through the device (three studies, 281 patients). The relative risk (95% CI) of bloodstaining of the device (nine studies, 859 patients) was 2.09 (1.46-3.00) for the streamlined liner of the pharynx airway compared with the laryngeal mask airway. Other adverse events were comparable. Subgroup analysis suggested that the insertion by novice users might be faster and more successful with the streamlined liner of the pharynx airway than the laryngeal mask airway; however, this was from only two studies and 186 patients. The method of size selection of the streamlined liner of the pharynx airway device might also affect the speed of insertion: choosing according to the width of the patient's thyroid cartilage, rather than height, may produce better results.

Adiponectin gene variants and the risk of coronary heart disease: a 16-year longitudinal study

OBJECTIVE

Circulating adiponectin levels have been shown to be associated with a risk of coronary heart disease (CHD). However, its primary role in protecting against the development of CHD remains controversial due to conflicting observations in prospective studies. To gain further insight into the primary role of adiponectin, our major objective was to investigate the relationship between single nucleotide polymorphisms (SNPs) of the adiponectin gene (ADIPOQ) and incident CHD in a population-based cohort with no CHD at baseline.

DESIGN AND METHODS

We conducted a 16-year longitudinal study in 2196 subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study (CRISPS). During 33 862 person-years of follow-up, 184 subjects developed CHD (cumulative incidence rate=5.4 per 1000 person-years). Nine ADIPOQ SNPs with potential functional relevance or shown to be associated with adiponectin levels and/or CHD were genotyped.

RESULTS

Among the nine ADIPOQ SNPs, +276G>T (rs1501299) was independently associated with incident CHD in men but not in women, even after adjustments for traditional cardiovascular risk factors (Padjusted=5.5×10(-3) to 0.023; hazard ratio=1.39-1.54). Furthermore, there was a significant association of the T allele of +276G>T with a lower adiponectin level (P=0.027; β (95% CI)=-0.05 (-0.10, -0.01).

CONCLUSIONS

This study demonstrated that +276G>T may be an independent predictor of CHD development. Our findings suggest that low adiponectin levels, as may be influenced by +276G>T, confer a higher risk of CHD, in keeping with a role of hypoadiponectinaemia in the development of CHD in the general population.

Fibroblast growth factor 21 as an emerging metabolic regulator: clinical perspectives

Fibroblast growth factor 21 (FGF21), a metabolic hormone predominantly produced by the liver, is also expressed in adipocytes and the pancreas. It regulates glucose and lipid metabolism through pleiotropic actions in these tissues and the brain. In mice, fasting leads to increased PPAR-α mediated expression of FGF21 in the liver where it stimulates gluconeogenesis, fatty acid oxidation, and ketogenesis, as an adaptive response to fasting and starvation. In the fed state, FGF21 acts as an autocrine factor in adipocytes, regulating the activity of PPAR-γ through a feed-forward loop mechanism. Administration of recombinant FGF21 has been shown to confer multiple metabolic benefits on insulin sensitivity, blood glucose, lipid profile and body weight in obese mice and diabetic monkeys, without mitogenic or other side effects. Such findings highlight the potential role of FGF21 as a therapeutic agent for obesity-related medical conditions. However, in human studies, high circulating FGF21 levels are found in obesity and its related cardiometabolic disorders including the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease and coronary artery disease. These findings may indicate the presence of FGF21 resistance or compensatory responses to the underlying metabolic stress, and imply the need for supraphysiological doses of FGF21 to achieve therapeutic efficacy. On the other hand, serum FGF21 has been implicated as a potential biomarker for the early detection of these cardiometabolic disorders. This review summarizes recent developments in the understanding of FGF21, from physiological and clinical perspectives.

Testicular cytotoxicity of intravenous methotrexate in rats

Although the testicular cytotoxicity of methotrexate has been evaluated in the rat, previous models have utilized routes other than the intravenous one, and have generally employed multiple-dose regimens. In this report, we describe testicular toxicity in the Sprague-Dawley rat following a single intravenous bolus of methotrexate (0-700 mg/kg body weight [BW]), with necropsy 56 days later. Testicular toxicity was evaluated qualitatively by histology and quantitatively by testicular weight, sperm head count, modified Johnsen score, repopulation index, and epididymal index. Effects of methotrexate on heart, lung, liver, and kidney histology were evaluated qualitatively. Oligospermia occurred at low and intermediate dosages of methotrexate, but testicular atrophy was not observed. LD50 at day five for methotrexate appears to be approximately 300 mg/kg BW using this regimen. This model will facilitate the study of techniques to avoid drug-induced testicular damage.

Magnesium: not essential for renal preservations by initial perfusion and hypothermic storage

Experimental observations regarding the role of divalent magnesium ion in hypothermic renal preservation have presumed the inclusion of this substance in synthetic preservation media. Retrospective analysis of the validity and application of these experimental data and consideration of the problems related to precipitation of magnesium salts in "intracellular" perfusates has instigated investigation related to the necessity of including this ingredient in our previously described hyperosmolar intracellular electrolyte solutions. Omission of magnesium chloride from these perfusates has not adversely affected ultimate renal function in canine kidneys preserved for 2 and 3 days following perfusion and storage in these solutions. The absolute necessity of including magnesium in these solutions in order to effect successful renal preservation is challenged.