Intraoperative mechanical ventilation strategies for obese patients: a systematic review and network meta-analysis

Several intraoperative ventilation strategies are available for obese patients. However, the same ventilation interventions have exhibited different effects on PaO2 /FIO2 concerning obese patients in different trials, and the issue remains controversial. Therefore, we conducted a network meta-analysis to identify the optimal mechanical ventilation strategy. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Embase, MEDLINE, CINAHL and Web of Science for studies published up to June 2014, and the PaO2 /FIO2 in obese patients given different mechanical ventilation strategies was assessed. We assessed the studies for eligibility and extracted data and then pooled the data and used a Bayesian fixed-effect model to combine direct comparisons with indirect evidence. Eligible studies evaluated different ventilation strategies for obese patients and reported the intraoperative PaO2 /FIO2 ratio, atelectasis and pulmonary compliance. Thirteen randomized controlled trials were included for network meta-analysis, including 476 patients who received 1 of 12 ventilation strategies. Volume-controlled ventilation with higher PEEP plus single recruitment manoeuvres (VCV + higher PEEP + single RM) was associated with the highest PaO2 /FiO2 ratio, improving intraoperative pulmonary compliance and reducing the incidence of intraoperative atelectasis.

A novel staging model to classify oesophageal squamous cell carcinoma patients in China

BACKGROUND

Oesophageal squamous cell carcinoma (ESCC) is the predominant subtype of oesophageal carcinoma in China, with the overall 5-year survival rate of <10%. The current tumour-node-metastasis (TNM) staging system has become so complex that it is not easy to use in the life expectancy assessment. We aim to combine clinical variables and biomarkers to develop and validate a relative simple and reliable model, named the FENSAM, for ESCC prognosis.

METHODS

To build the FENSAM, we analysed 22 potential prognostic factors from 461 patients, including 9 biomarkers (Ezrin, Fascin, desmocollin 2 (DSC2), pFascin, activating transcription factor 3 (ATF3), connective-tissue growth factor (CTGF), neutrophil gelatinase-associated lipocalin (NGAL), NGAL receptor (NGALR), and cysteine-rich angiogenic protein 61 (CYR61)) and other 13 clinical variables. We selected significant factors associated with survival of ESCC patients, and used them to build our FENSAM model. We then obtained the hazard risk score of the model to classify ESCC patients. In addition, we validated the model in an independent cohort of 290 patients from the same hospital. The predictive performance of the model was assessed by the Area under the Receiver Operating Characteristic Curve (AUC) and Kaplan-Meier survival analysis.

RESULTS

We found six markers significantly associated with survival of ESCC patients (Ezrin, Fascin, ATF3, surgery extent, N-stage, and M-stage). They were combined to create a novel four-stage FENSAM model for patients' classification. FENSAM possessed a high classification precision similar to the TNM staging system, but with a much simpler model. The efficiency of FENSAM was evaluated by different quantiles of AUC and the results of survival analysis. The validation result demonstrated the potential of the FENSAM model to improve classification accuracy for ESCC patients.

CONCLUSIONS

FENSAM provides an alternative classifier for ESCC patients with a high classification precision using a simple model.

Antiviral activity and underlying molecular mechanisms of Matrine against porcine reproductive and respiratory syndrome virus in vitro

Porcine reproductive and respiratory syndrome (PRRS), caused by porcine reproductive and respiratory syndrome virus (PRRSV), is an acute infectious disease. The prevalence of PRRS has made swine industry suffered huge financial losses. Matrine, a natural compound, has been demonstrated to possess anti-PRRSV activity in Marc-145 cells. However, the underlying molecular mechanisms were still unknown. The main objective of our study was to discuss the effect of Matrine on PRRSV N protein expression and PRRSV induced apoptosis. Indirect immunofluorescence assay (IFA) and Western blot were used to assess the effect of Matrine on N protein expression. Apoptosis was analyzed by fluorescence staining. In addition, the effect of Matrine on caspase-3 activation was investigated by Western blot. Indirect immunofluorescence assay and Western blot analysis demonstrated that Matrine could inhibit N protein expression in Marc-145 cells. And Matrine was found to be able to impair PRRSV-induced apoptosis by inhibiting caspase-3 activation.

Sodium tanshinone IIA sulfonate inhibits porcine reproductive and respiratory syndrome virus via suppressing N gene expression and blocking virus-induced apoptosis

BACKGROUND

Porcine reproductive and respiratory syndrome virus (PRRSV) causes significant economic loss in the swine industry. Currently, there is no effective way to prevent PRRSV infection. Sodium tanshinone IIA sulfonate (STS), a natural compound derived from Salvia miltiorrhiza, was shown to possess anti-PRRSV activity, but the underlying mechanisms remain unclear. The objective of this study was to investigate the effect of STS on PRRSV-induced cell apoptosis and PRRSV N protein expression pattern.

METHODS

Relative quantification real-time PCR was used to evaluate the inhibition of STS on N gene expression. Simultaneously indirect immunofluorescence assay (IFA) and western blot were used to assess the effect on N protein expression. Apoptosis was analysed using fluorescence microscope with an annexin V-EGFP kit. The effect of STS on caspase-3 cleaving was assessed by western blot.

RESULTS

Our results showed that STS could inhibit viral N gene expression at both the messenger RNA stage and at the protein level in PRRSV-infected cells in a dose-dependent manner. In addition, STS could also rescue PRRSV-induced apoptosis.

CONCLUSIONS

Our data suggest that STS may serve as a base compound for developing more effective drugs against PRRSV infection.

Efficient inscription of Bragg gratings in As2S3 fibers using near bandgap light

Efficient inscription of Fiber Bragg gratings (FBGs) in single-mode, thin cladding As(2)S(3) fibers is demonstrated by using near bandgap light at 532 nm. The FBGs with the reflectivity of over 80% can be induced in only 80-90 s, substantially faster than in previous reports. The dynamics of the grating growth are investigated in the photosensitivity process, showing a fast blue shift of the Bragg wavelength and then a somewhat slower red shift. The aging of the grating after fabrication is also reported, indicating a 37% decay of the grating strength.

A 34K SNP genotyping array for Populus trichocarpa: design, application to the study of natural populations and transferability to other Populus species

Genetic mapping of quantitative traits requires genotypic data for large numbers of markers in many individuals. For such studies, the use of large single nucleotide polymorphism (SNP) genotyping arrays still offers the most cost-effective solution. Herein we report on the design and performance of a SNP genotyping array for Populus trichocarpa (black cottonwood). This genotyping array was designed with SNPs pre-ascertained in 34 wild accessions covering most of the species latitudinal range. We adopted a candidate gene approach to the array design that resulted in the selection of 34 131 SNPs, the majority of which are located in, or within 2 kb of, 3543 candidate genes. A subset of the SNPs on the array (539) was selected based on patterns of variation among the SNP discovery accessions. We show that more than 95% of the loci produce high quality genotypes and that the genotyping error rate for these is likely below 2%. We demonstrate that even among small numbers of samples (n = 10) from local populations over 84% of loci are polymorphic. We also tested the applicability of the array to other species in the genus and found that the number of polymorphic loci decreases rapidly with genetic distance, with the largest numbers detected in other species in section Tacamahaca. Finally, we provide evidence for the utility of the array to address evolutionary questions such as intraspecific studies of genetic differentiation, species assignment and the detection of natural hybrids.

Insight into gene evolution within Cervidae and Bovidae through genetic variation in MHC-DQA in the black muntjac (Muntiacus crinifrons)

The critical role that the major histocompatibility complex plays in the immune recognition of parasites and pathogens makes its evolutionary dynamics exceptionally relevant to ecology, population biology, and conservation studies. The black muntjac is a rare deer endemic to a small mountainous region in eastern China. We found that this species has two DQA loci through cDNA expression and sequence variation analysis. The level of variation at both DQA loci was found to be extremely low (three alleles for DQA1 and four alleles for DQA2), possibly because of past bottlenecks and the species' relatively solitary behavior pattern. The ratio of d(N)/d(S) in the putative peptide binding region of the DQA2 locus (13.36, P = 0.012) was significantly larger than one but not that of DQA1 (0.94, P = 0.95), suggesting strong positive selection at the DQA2 but not at the DQA1 locus. This difference might reflect different sets of evolutionary selection pressures acting on the two loci. The phylogenetic tree showed that DQA1 alleles from two species of Cervidae and two of Bovidae grouped together, as did the DQA2 alleles. However, different genes from the four species were located in separate branches. These results lead us to suggest that these DQA alleles are derived from primordial DQA genes from a common ancestor and are maintained in Cervidae and Bovidae since their divergence around 25.5-27.8 million years ago.

A typical endo-xylanase from Streptomyces rameus L2001 and its unique characteristics in xylooligosaccharide production

The activity of the extracellular xylanase produced by Streptomyces rameus L2001 against different xylans and xylooligosaccharides (XOS) was investigated. The main products of hydrolysis of birchwood xylan and oat-spelt xylan by the S. rameus L2001 xylanase were xylobiose (X2) and xylotriose (X3), suggesting that this is an endo-acting xylanase. This was confirmed by analysis of XOS degradation products. The enzyme hardly hydrolyzed X2 and X3, but hydrolyzed xylotetraose (X4) and xylopentaose (X5) producing mainly X2 and X3 through transglycosylation. Depending on the substrate, different quantities of reducing sugars were produced by the xylanase: 150 mg/g from corncob, 105 mg/g from bean culms, and 133 mg/g from bagasse. With the bagasse substrate, the xylanase yielded 2.36, 2.76, 2.03, and 2.17 mg/mL of X2, X3, X4, and X5, respectively. The structure of xylobiose and xylotriose from the hydrolysis of corncob xylan was identified by MS and NMR. The production of XOS from various agricultural wastes has potential industrial applications. This is the first report of XOS production by S. rameus L2001.

Reconfigurable photonic crystal waveguides created by selective liquid infiltration

We experimentally demonstrate reconfigurable photonic crystal waveguides created directly by infiltrating high refractive index (n≈2.01) liquids into selected air holes of a two-dimensional hexagonal periodic lattice in silicon. The resulting effective index contrast is large enough that a single row of infiltrated holes enables light propagation at near-infrared wavelengths. We include a detailed comparison between modeling and experimental results of single line defect waveguides and show how our infiltration procedure is reversible and repeatable. We achieve infiltration accuracy down to the single air hole level and demonstrate control on the volume of liquid infused into the holes by simply changing the infiltration velocity. This method is promising for achieving a wide range of targeted optical functionalities on a "blank" photonic crystal membrane that can be reconfigured on demand.

Cavity enhanced stimulated Brillouin scattering in an optical chip for multiorder Stokes generation

We report the first demonstration of on-chip cascaded stimulated Brillouin scattering (SBS). Cascaded SBS is characterized in a 4 cm long chalcogenide (As₂S₃) rib waveguide where the end facet reflections provide a monolithic Fabry-Perot (FP) resonator. The presence of the FP cavity reduces the Brillouin gain threshold, which enables observation of cascaded SBS at reduced pump powers. We observe up to three orders of Stokes waves in the backscattered signal at a coupled peak power of 1.34 W. Anti-Stokes waves due to four-wave mixing between the pump and the Stokes wave were observed in the forward spectrum.

A rapid method for the determination of microbial biomass by dry weight using a moisture analyser with an infrared heating source and an analytical balance

AIMS

Microbial biomass is an important biotechnological parameter. The traditional method for its determination involves an oven-drying step and equilibration to room temperature before weighing, and it is tedious and time consuming. This work studied the utilisation of a moisture analyser consisting of an efficient infrared-heating module and an analytical balance for the determination of microbial biomass by dry weight.

METHODS AND RESULTS

The method duration depended on the sample volume and was between 7 and 40 min for sample volumes of 1-10 ml. The method precision depended on the total dry weight analysed - 10 mg of total dry weight being sufficient to achieve coefficients of variation of 5% or less. Comparison with the conventional oven method provided a correlation coefficient r(2) of 0.99. The recovery of an internal standard ranged between 94.2 and 106.4% with a precision of 1.39-4.53%CV.

CONCLUSIONS

Validation revealed sufficient method accuracy, precision and robustness and was successfully applied to the study of yeast and bacterial growth kinetics. Techniques are discussed that allow for increased method precision at low biomass concentrations, and equations are provided to estimate required drying time and method precision based on sample volume and total sample dry weight, respectively.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work presents a rapid method for the determination of microbial biomass, allowing for the timely implementation of biomass-based information in biotechnological and laboratory protocols.

Investigation of Propofol Concentrations in Human Breath by Solid-Phase Microextraction Gas Chromatography–Mass Spectrometry

Propofol has been detected in human breath after being used as an intravenous anaesthetic, and this could provide a noninvasive method for monitoring propofol anaesthesia. The physicochemical properties of propofol allow it to diffuse across the alveolocapillary membrane and to be prepared as a calibration gas. In this study, headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC–MS), coupled with an external standard, was applied to assess propofol levels in the breath and plasma from three subjects under intravenous anaesthesia. Lower quantitation limits were 3.6 ng/l and 0.2 mg/l for propofol analysis in breath and arterial plasma, respectively. Intraday precision and recovery percentages for propofol detection in breath were 4.3-6.7% and 98-108%, respectively, and in plasma they were 3.8-6.1% and 90.1-125.1%, respectively. Propofol concentrations were 4.3-33.5 ng/l in breath and 3.2-6.8 mg/l in arterial plasma. A correlation was shown between propofol concentration in breath and plasma. Thus, HS-SPME-GC–MS, coupled with an external standard, could be a reliable and sensitive analytical technique for detecting propofol in breath during anaesthesia.

Enhancement of Q(m) by co-doping of Li and Cu to potassium sodium niobate lead-free ceramics

Lead-free piezoelectric ceramics KNN modified by Li-substitution and CuO addition have been synthesized, and the piezoelectric and dielectric properties were measured. A morphotropic phase boundary (MPB) between orthorhombic and tetragonal phases was formed with Li-substitution. The co doping of Li and Cu markedly enhanced the mechanical quality factor (Q(m)) in comparison with the sole doping of Li and Cu. Anomalous anti ferroelectric-like hysteresis curves were observed in 2 mol% CuO-doped ceramics. The anti-ferroelectric-like curves were changed to that of normal ferroelectrics following poling. A model based on the formation of the internal bias field (Ei) due to the movements of space charges was proposed to explain these phenomena. It was considered that the Ei stabilized the spontaneous polarization (Ps) and suppressed the domain wall motion to enhance the Q(m). The highest Qm obtained in this study was 742. The [(Na0(0.5)K0(0.5))(0.96)Li0(0.04) ] NbO(3) + 0.45 mol% CuO ceramics showed a high Q(m) value of 414 with a high piezoelectric constant d(33) of 100 pC/N.

Carbon nanotube Schottky diode: an atomic perspective

The electron transport properties of semiconducting carbon nanotube (SCNT) Schottky diodes are investigated with atomic models using density functional theory and the non-equilibrium Green's function method. We model the SCNT Schottky diode as a SCNT embedded in the metal electrode, which resembles the experimental set-up. Our study reveals that the rectification behaviour of the diode is mainly due to the asymmetric electron transmission function distribution in the conduction and valence bands and can be improved by changing metal-SCNT contact geometries. The threshold voltage of the diode depends on the electron Schottky barrier height which can be tuned by altering the diameter of the SCNT. Contrary to the traditional perception, the metal-SCNT contact region exhibits better conductivity than the other parts of the diode.