Facile construction of photocatalytic cellulose-based sponge with stable flotation properties as efficient and recyclable photocatalysts for sewage treatment.

Dispersion and recycling of powdered nano-photocatalysts for water purification is still not an easy task. The self-supporting and floating photocatalytic cellulose-based sponges ware conveniently prepared by anchoring BiOX nanosheet arrays on cellulose-based sponge's surface. The introduction of sodium alginate into the cellulose-based sponge significantly enhanced the electrostatic adsorption of bismuth oxygen ions and promoted the formation of bismuth oxyhalide (BiOX) crystal nuclei. Among the photocatalytic cellulose-based sponges, the sponge (BiOBr-SA/CNF) modified with bismuth oxybromide displayed excellent photocatalytic ability for photodegrading 96.1 % rhodamine B within 90 min under 300 W Xe lamp irradiation (λ > 400 nm). The loading of bismuth oxybromide on cellulose-based sponge's surface improves the flotation stability of the cellulose-based sponge. Benefiting from excellent load fastness of bismuth oxybromide nanosheet and flotation stability of BiOBr-SA/CNF sponge, after 5 cycles of recycling, the photodegradation rates of BiOBr-SA/CNF sponge to rhodamine B remained above 90.2 % (90 min), and it also has excellent photocatalytic degradation effect on methyl orange and herbicide isoproteron. This work may provide a convenient and efficient method to construct self-supporting and floating photocatalytic sponges using cellulose based materials as substrates for sewage treatment.

Impact of an Intervention to Control Imipenem-Resistant Acinetobacter baumannii and Its Resistance Mechanisms: An 8-Year Survey.

BACKGROUND: This study aimed to examine the impact of an intervention carried out in 2011 to combat multi-drug resistance and outbreaks of imipenem-resistant Acinetobacter baumannii (IRAB), and to explore its resistance mechanism. METHODS: A total of 2572 isolates of A. baumannii, including 1673 IRAB isolates, were collected between 2007 and 2014. An intervention was implemented to control A. baumannii resistance and outbreaks. Antimicrobial susceptibility was tested by calculating minimal inhibitory concentrations (MICs), and outbreaks were typed using pulsed-field gel electrophoresis (PFGE). Resistance mechanisms were explored by polymerase chain reaction (PCR) and whole genome sequencing (WGS). RESULTS: Following the intervention in 2011, the resistance rates of A. baumannii to almost all tested antibiotics decreased, from 85.3 to 72.6% for imipenem, 100 to 80.8% for ceftriaxone, and 45.0 to 6.9% for tigecycline. The intervention resulted in a decrease in the number (seven to five), duration (8-3 months), and departments (five to three) affected by outbreaks; no outbreaks occurred in 2011. After the intervention, only bla AMPC (76.47 to 100%) and bla TEM- 1 (75.74 to 96.92%) increased (P < 0.0001); whereas bla GES- 1 (32.35 to 3.07%), bla PER- 1 (21.32 to 1.54%), bla OXA- 58 (60.29 to 1.54%), carO (37.50 to 7.69%), and adeB (9.56 to 3.08%) decreased (P < 0.0001). Interestingly, the frequency of class B ß-lactamase genes decreased from 91.18% (bla SPM- 1) and 61.03% (bla IMP- 1) to 0%, while that of class D bla OXA- 23 increased to 96.92% (P < 0.0001). WGS showed that the major PFGE types causing outbreaks each year (type 01, 11, 18, 23, 26, and 31) carried the same resistance genes (bla KPC- 1, bla ADC- 25, bla OXA- 66, and adeABC), AdeR-S mutations (G186V and A136V), and a partially blocked porin channel CarO. Meanwhile, plasmids harboring bla OXA- 23 were found after the intervention. CONCLUSION: The intervention was highly effective in reducing multi-drug resistance of A. baumannii and IRAB outbreaks in the long term. The resistance mechanisms of IRAB may involve genes encoding ß-lactamases, efflux pump overexpression, outer membrane porin blockade, and plasmids; in particular, clonal spread of bla OXA- 23 was the major cause of outbreaks. Similar interventions may also help reduce bacterial resistance rates and outbreaks in other hospitals.

Simplified, rapid, and inexpensive estimation of water primary productivity based on chlorophyll fluorescence parameter Fo.

Primary productivity in water environment relies on the photosynthetic production of microalgae. Chlorophyll fluorescence is widely used to detect the growth status and photosynthetic efficiency of microalgae. In this study, a method was established to determine the Chl a content, cell density of microalgae, and water primary productivity by measuring chlorophyll fluorescence parameter Fo. A significant linear relationship between chlorophyll fluorescence parameter Fo and Chl a content of microalgae, as well as between Fo and cell density, was observed under pure-culture conditions. Furthermore, water samples collected from natural aquaculture ponds were used to validate the correlation between Fo and water primary productivity, which is closely related to Chl a content in water. Thus, for a given pure culture of microalgae or phytoplankton (mainly microalgae) in aquaculture ponds or other natural ponds for which the relationship between the Fo value and Chl a content or cell density could be established, Chl a content or cell density could be determined by measuring the Fo value, thereby making it possible to calculate the water primary productivity. It is believed that this method can provide a convenient way of efficiently estimating the primary productivity in natural aquaculture ponds and bringing economic value in limnetic ecology assessment, as well as in algal bloom monitoring.

Determination of the optimal reaction conditions for the preparation of highly substituted carboxymethyl Cassia tora gum.

Highly substituted carboxymethyl Cassia tora gum (CM-CTG) was prepared from CTG by treatment with monochloroacetic acid (MCA) in ethanolic aqueous solutions after alkalization under different reaction conditions. The influence of the etherification temperature, alkalization and etherification times, molar ratio of sodium hydroxide to MCA (nNaOH/nMCA), theoretical degree of substitution (DSt), and weight percentage of water (WH2O%) in the solution on the degree of substitution (DS) and reaction efficiency (RE) of the reaction were investigated. Optimum preparation conditions for a CM-CTG with DS of 1.05 are: etherification temperature, 60°C; alkalization time, 60min; etherification time, 180min; nNaOH/nMCA, 2.1; DSt, 1.4; and WH2O%, 20%. Fourier-transform infrared analysis of the products indicated that carboxymethylation was successful. Rheological studies show that all the CM-CTG pastes are pseudoplastic fluids, and the shear sensitivity varies with DS. The degree of crystallinity of CM-CTG decreases with increasing DS, as shown by X-ray diffraction measurements.

Synthesis and evaluation of tetrahydroindazole derivatives as sigma-2 receptor ligands.

A series of tetrahydroindazole derivatives were synthesized and evaluated for their affinities for both sigma-1 and sigma-2 receptors. These compounds are hybrid structures of a tetrahydroindazole substituted benzamide and a 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline moiety or a 9-azabicyclo[3.3.1]nonan-3-yl-amine moiety. These newly synthesized hybrid analogs showed various affinities for sigma-2 receptor without any significant affinities for sigma-1 receptor. In particular, compounds 12, 15b, 15c, and 15d, demonstrated moderate affinity and excellent selectivity for sigma-2 receptor. It is interesting to note that 3-5 carbon units between the tetrahydroindazole substituted benzamide and the 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline moiety are appropriate for sigma-2 receptor binding. No substitution on the 9-aza nitrogen is proper for sigma-2 affinity in the 2-(9-azabicyclo[3.3.1]nonan-3-yl-amino)-4-(3,6,6-trimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indazol-1-yl)benzamide analogs.

Sigma-2 receptor ligands and their perspectives in cancer diagnosis and therapy.

The sigma-2 receptor is highly expressed in various rapidly proliferating cancer cells and regarded as a cancer cell biomarker. Selective sigma-2 ligands have been shown to specifically label the tumor sites, induce cancer cells to undergo apoptosis, and inhibit tumor growth. Sigma-2 ligands are potentially useful as cancer diagnostics, anticancer therapeutics, or adjuvant anticancer treatment agents. However, both the cloning of this receptor and the identification of its endogenous ligand have not been successful, and the lack of structural information has severely hindered the understanding of its physiological roles, its signaling pathways, and the development of more selective sigma-2 ligands. Recent data have implicated that sigma-2 binding sites are within the lipid rafts and that PGRMC1 (progesterone receptor membrane component 1) complex and sigma-2 receptor may be coupled with EGFR (epidermal growth factor receptor), mTOR (mammalian target of rapamycin), caspases, and ion channels. Due to its promising applications in cancer management, there are rapidly increasing research efforts that are being directed into this field. This review article updates the current understanding of sigma-2 receptor and its potential physiological roles, applications, interaction with other effectors, with special focuses on the development of sigma-2 ligands, their chemical structures, pharmacological profiles, applications in imaging and anticancer therapy.

[Rapid determination of fatty acids in soybean oils by transmission reflection-near infrared spectroscopy].

In the present research, a novel method was established for determination of five fatty acids in soybean oil by transmission reflection-near infrared spectroscopy. The optimum conditions of mathematics model of five components (C16:0, C18:0, C18:1, C18:2 and C18:3) were studied, including the sample set selection, chemical value analysis, the detection methods and condition. Chemical value was analyzed by gas chromatography. One hundred fifty eight samples were selected, 138 for modeling set, 10 for testing set and 10 for unknown sample set. All samples were placed in sample pools and scanned by transmission reflection-near infrared spectrum after sonicleaning for 10 minute. The 1100-2500 nm spectral region was analyzed. The acquisition interval was 2 nm. Modified partial least square method was chosen for calibration mode creating. Result demonstrated that the 1-VR of five fatty acids between the reference value of the modeling sample set and the near infrared spectrum predictive value were 0.8839, 0.5830, 0.9001, 0.9776 and 0.9596, respectively. And the SECV of five fatty acids between the reference value of the modeling sample set and the near infrared spectrum predictive value were 0.42, 0.29, 0.83, 0.46 and 0.21, respectively. The standard error of the calibration (SECV) of five fatty acids between the reference value of testing sample set and the near infrared spectrum predictive value were 0.891, 0.790, 0.900, 0.976 and 0.942, respectively. It was proved that the near infrared spectrum predictive value was linear with chemical value and the mathematical model established for fatty acids of soybean oil was feasible. For validation, 10 unknown samples were selected for analysis by near infrared spectrum. The result demonstrated that the relative standard deviation between predict value and chemical value was less than 5.50%. That was to say that transmission reflection-near infrared spectroscopy had a good veracity in analysis of fatty acids of soybean oil.