Photolysis of sulfamethazine using UV irradiation in an aqueous medium

Although many studies have been focused on the photochemistry of antibiotics, the roles of reactive species in photolysis and the effects of dissolved substances on antibiotic photochemical behavior have been poorly examined. The photolytic behaviors of sulfamethazine (SMN) in pure water were investigated via adding different scavengers to quench the active species. Results showed that decomposition of the triplet-excited state of SMN (³SMN*) by direct photolysis was the main path of SMN photolysis in water. Moreover, self-sensitized SMN cannot be ignored during SMN photodegradation. The main photoproducts of SMN were identified by LC-MS/MS, which indicated that SMN could not be mineralized although the photolysis under UV was effective. The effects of Cl⁻, NO₃⁻, and fulvic acid (FA) (common substances in natural water) on SMN photolytic behaviors were also studied. The triplet-induced halogenation of SMN increases the ionic strength and reduces the ground state SMN; these are the primary causes of promotion of SMN photolysis by Cl⁻. More ˙OH produced in the presence of NO₃⁻ could promote SMN photolysis. Competitive absorption of photons of FA with SMN and ROS scavenged by FA were the main reasons for the inhibition of SMN photolysis. The research findings are helpful for further studies on the environmental risks of ACs in natural waters and promoting the development of AC pollution treatment technology.

The role of reactive species in SMN photolysis and the effects of dissolved substances on SMN photochemical behavior.     

Anti-phytopathogenic sesquiterpenoid-xanthone adducts from potato endophytic fungus Bipolaris eleusines

A bioguided separation on the cultures of the potato endophytic fungus Bipolaris eleusines led to the isolation of two anti-phytopathogenic (Alternaria solani) sesquiterpenoid-xanthone adducts, namely bipolins I and J (1 and 2). Their structures were established via extensive spectroscopic analysis. Compounds 1 and 2 exhibit potent inhibitory activity against A. solani with MIC values of 8 and 16 μg mL⁻¹, respectively.

Two sativene sesquiterpenoid-xanthone adducts from potato endophytic fungus Bipolaris eleusines     

The influence of different Si : C ratios on the electrochemical performance of silicon/carbon layered film anodes for lithium-ion batteries

With a high specific capacity (4200 mA h g⁻¹), silicon based materials have become the most promising anode materials in lithium-ions batteries. However, the large volume expansion makes the capacity reduce rapidly. In this work, a periodic silicon/carbon (Si/C) multilayer thin film was synthesized by magnetron sputtering method on copper foil. The titanium (Ti) film (about 20 nm) as the transition layer was deposited on the copper foil prior to the deposition of the multilayer film. Superior electrochemical lithium storage performance was obtained by the multilayer thin film. The initial discharge and charge specific capacity of the Si (15 nm)/C (5 nm) multilayer film anode are 2640 mA h g⁻¹ and 2560 mA h g⁻¹ with an initial coulombic efficiency of ∼97%. The retention specific capacity is about 2300 mA h g⁻¹ and there is ∼87% capacity retention after 200 cycles.

With a high specific capacity (4200 mA h g⁻¹), silicon based materials have become the most promising anode materials in lithium-ions batteries.     

Controllable thermal and pH responsive behavior of PEG based hydrogels and applications for dye adsorption and release

A series of controllable thermal and pH dual-responsive copolymeric hydrogels (PMA) were prepared by a one-pot reaction with poly(ethylene glycol) methyl ether acrylate (PEGA), 2-methoxyethyl acrylate (MEA) and acroleic acid (AA). The hydrogels exhibited good mechanical properties and a sensitive response to pH and temperature. Besides, the Lower Critical Solution Temperature (LCST) of the hydrogels can be adjusted from 37 °C to 58 °C by changing the content of AA. The hydrogels also showed excellent selective adsorption properties. The maximum adsorption quantity of organic cationic dye brilliant green and methylene blue were 0.49 mg mg⁻¹ and 0.42 mg mg⁻¹ respectively, much better than previous reports. Furthermore, using the thermal and pH responsibility, the PMA hydrogels can release the adsorbed molecules with control. Nearly 95% of carriers could be released at pH 4.01 and 65 °C over 8 h. The regeneration ability makes the materials easy to reuse many times. Due to these properties, these dual-responsive hydrogels have great potential applications in various fields for adsorption, drug delivery, release and tissue engineering.

Controllable thermal and pH responsive hydrogels not only showed good stimuli-response and mechanical properties, but also have excellent adsorption properties.     

Effect of high-frequency alternating current transcutaneous stimulation over muscle strength: a controlled pilot study

Background

High-frequency alternating currents of greater than 1 kHz applied on peripheral nerves has been used in animal studies to produce a motor nerve block. It has been evidenced that frequencies higher than 5 kHz are necessary to produce a complete peripheral nerve block in primates, whose nerve thickness is more similar to humans. The aim of the study was to determine the effect on muscle strength after the application of a high-frequency stimulation at 5 and 10 kHz compared to sham stimulation in healthy volunteers.

Findings

Transcutaneous stimulation at 5 kHz, 10 kHz and sham stimulation were applied to eleven healthy volunteers over the ulnar and median nerves for 20 min. Maximal handgrip strength was measured before, during, immediately after the intervention, and 10 min after the end of intervention. The 10 kHz stimulation showed a lower handgrip strength during the intervention (28.1 N, SEM 3.9) when compared to 5 kHz (31.1 N, SEM 3.6; p?<?0.001) and to sham stimulation (33.7 N, SEM 3.9; p?<?0.001). Furthermore, only stimulation at 10 kHz decreased handgrip strength when compared to baseline.

Conclusions

These findings suggest high-frequency stimulation has an inhibitory effect over muscle strength. Future studies are required in patients that are characterized by motor hyperactive such as spasticity or tremors.

Clinical trial registration

NCT, NCT03169049. Registered on 30 May 2017

     

Gentamicin may have no effect on mortality of staphylococcal prosthetic valve endocarditis

Purpose

To analyze the influence of adding gentamicin to a regimen consisting of β-lactam or vancomycin plus rifampicin on survival in patients suffering from Staphylococcal prosthetic valve endocarditis (SPVE).

Right ventricular septomarginal trabeculation hypertrophy is associated with disease severity in patients with pulmonary arterial hypertension

To characterize the morphological change in the right ventricle (RV) of patients with pulmonary artery hypertension (PAH) and further explore the correlation between septomarginal trabeculation (SMT) and right ventricular (RV) function, myocardial fibrosis, and exercise capacity in patients with PAH. Sixty untreated PAH patients were prospectively included from May 2016 to April 2017. All patients underwent comprehensive clinical evaluation and cardiac magnetic resonance (CMR). The area and diameter of the basal segment of SMT, and the mass of SMT were measured on cine SSFP images. Relationship between parameters of SMT and RV ejection fraction (RVEF), 6 min walking distance (6MWD), myocardial fibrosis and pulmonary vascular resistance (PVR) were evaluated by Pearson’s correlation and logistic regression. Predictive performance of SMT parameters for reduced RVEF or impaired 6MWD was evaluated by receiver operating characteristics (ROC) analysis. Compared with SMT diameter index and mass index, SMT area index (SMT Ai) in basal segment was the best parameter to show correlation with RVEF (r?=???0.496, P?<?0.001), 6MWD (r?=???0.619, P?<?0.001), and inferior insertion point (I IP) extracelluar volume (ECV) (r?=?0.365, P?=?0.008). ROC showed that SMT Ai had the strongest predictive value for reduced RVEF (AUC?=?0.756), and impaired 6MWD (AUC?=?0.813). SMT parameters were closely correlated with RV systolic function and 6MWD in patients with PAH. SMT Ai is a simple imaging indicator for the severity of PAH.     

鼻内镜下眶下壁骨折修复方式及材料应用研究进展

眼眶骨折是指外力撞击眼部引起面中部多发骨折的外伤,按骨折性质大致可分为：爆裂性眶壁骨折、复合性眶壁骨折、复杂性眶壁骨折;按部位可分为眶下壁骨折、眶内侧壁骨折、眶下壁和眶内侧壁联合骨折,其中以眶下壁骨折最为常见。随着医学技术的进步与发展,手术修复是目前治疗眶下壁骨折最理想的方法,利用鼻内镜联合传统入路或直接经鼻腔入路手术具有可直视眶壁骨折的部位、直接评估伤情及制定手术方案等优势。本文针对眶下壁骨折的诊断、辅助检查、手术指征、鼻内镜修复眼眶骨折的手术术式、术式的优点和缺点及各种修复材料的特点等内容作一综述。