We report the measurement of the frequency noise power spectral density of a quantum cascade laser emitting at 2.5THz. The technique is based on heterodyning the laser emission frequency with a ...harmonic of the repetition rate of a near-infrared laser comb. This generates a beatnote in the radio frequency range that is demodulated using a tracking oscillator allowing measurement of the frequency noise. We find that the latter is strongly affected by the level of optical feedback, and obtain an intrinsic linewidth of ~230Hz, for an output power of 2mW.
Octahedral molecular sieve (OMS) materials classified by their different tunnel sizes are defined by edge-sharing MnO6 octahedra. Four different OMS materials (OMS-1, OMS-2, OMS-5, and OMS-6) are ...benchmarked for ethane (C2H6) and cyclohexane (C6H12) oxidative dehydrogenation (ODH) and compared with commercial MnO2, M1 phase MoVTeNb oxide, and vanadium oxide (V2O5). The accessibility of the quadrilateral tunnels of the OMS materials to C2H6 and C6H12 were further evaluated using density functional theory (DFT). C2H6 and C6H12 ODH rates for the four OMS materials were higher than those measured for commercial MnO2, MoVTeNbO, and V2O5. The C2H6/C6H12 rate ratios on the four OMS oxides are larger than V2O5. Rate relations for selective accessibility for C2H6 in small pores, accessibility to both molecules in large pores, and the presence of tunnel defects are discussed. Product selectivities show slightly higher ethylene selectivity in smaller pores suggesting possible connections between pore confinement and selectivity.
Porous octahedral molecular sieves displaying different tunnel structures are prepared to study Oxidative dehydrogenation (ODH) reaction using ethane and cyclohexane as substrates. The assessment of the micropore and mesopore pore volumes and compared to the ethane to cyclohexane rate ratios. A relationship in ODH rates and pore sizes and pore volumes was observed, with larger tunnel sizes not being discriminatory to either substrate compared to smaller tunnels that are highly active for ethane and not cyclohexane.
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•Oxidative dehydrogenation using Octahedral Molecular Sieves (OMS).•Determination of microporous and mesoporous pore volumes and ratios.•A possible connection between pore confinement and selectivity from ethylene ODH.•C2H6 and C6H12 ODH rates for OMS materials were higher than measured for standards.
The available treatment options for Clostridium difficile infection (CDI) are limited by high recurrence rates. Surotomycin was a novel bactericidal cyclic lipopeptide in development to treat CDI ...that demonstrated non-inferiority to vancomycin in a Phase 2 trial.
To assess surotomycin safety and clinical response (non-inferiority versus vancomycin) at the end of treatment (EOT) of CDI. Additionally, to assess surotomycin response over time and sustained response at 30-40 days post-EOT (superiority versus vancomycin).
Patients with CDI were randomized (1:1) to receive twice-daily oral surotomycin 250 mg alternating with twice-daily placebo or four-times-daily oral vancomycin 125 mg for 10 days in this Phase 3, double-blind, multicentre, international trial. Clinical response over time and sustained clinical response were monitored until the end of the trial, through a follow-up period of 30-40 days. Clinical Trial Registration: NCT01598311.
A total of 285 and 292 patients with confirmed CDI were randomized to receive surotomycin and vancomycin, respectively. Surotomycin-associated clinical response at EOT was non-inferior to vancomycin (surotomycin/vancomycin: 83.4%/82.1%; difference 1.4%, 95% CI - 4.9, 7.6). Following treatment with surotomycin, both clinical response over time (stratified log-rank test, P = 0.277) and sustained clinical response (63.3%/59.0%; difference 4.3%, 95% CI - 3.6, 12.2) did not demonstrate superiority versus vancomycin at end of trial. Both treatments were generally well tolerated.
Surotomycin demonstrated non-inferiority to vancomycin for CDI clinical response at EOT. Surotomycin did not demonstrate superiority to vancomycin for clinical response over time or sustained clinical response rate.
The risk of pacemaker pocket infections (PPIs) is rare with good antisepsis techniques and use of advanced antibiotics. However, injudicious antibiotic usage leads to the rise of multidrug-resistant ...bacteria, which may cause PPI. Few reports exist about the microbial spectrum of the PPI from our country, prompting us to study the same.
We conducted this retrospective observational study for 3 years (January 2013-February 2016) from all the patients with PPI. We collected the relevant clinical samples (blood and pus) for the microbial culture using a standard protocol. We included 100 samples collected from the medical staff and the hospital environment as a control sample. The data were analyzed using appropriate statistical methods and a P< 0.05 was considered statistically significant.
Our data showed that 17 out of 160 (10.6%) patients had PPI. Coagulase negative Staphylococcus sp. was isolated in 7 (41.2%) patients, followed by Staphylococcus aureus in 4 patients (23.5%). Other isolated bacteria include multidrug-resistant Burkholderia cepacia (n = 3), Mycobacterium abscessus (n = 2) and polymicrobial infection in a single patient. One out of hundred surveillance samples grew B. cepacia.
Our data revealed a high incidence of Gram-positive cocci causing PPI. Every hospital should formulate their antibiotic policy based on the pattern of the hospital flora and their drug sensitivity.
Aberrant regulation of cholesterol homeostasis is associated with obesity as well as multiple types of cancer. However, the mechanism behind these is largely missing. Here, we show that microRNA ...(miRNA)-128-2 is not only a pro-apoptotic microRNA but it also alters the expression of genes involved in cellular cholesterol homeostasis. Cholesterol efflux via ATP-binding cassette transporters (ABCA1 and ABCG1) is a mechanism for cells to eliminate excess cholesterol and prevent cellular cholesterol accumulation. The regulation of these pathways is complex with transcriptional regulation by sterol-regulatory element-binding protein (SREBP) and liver X receptor/retinoid X receptor (RXR) transcription factors but poorly understood at the post-transcriptional levels. MiR-128-2 increases the expression of SREBP2 and decreases the expression of SREBP1 in HepG2, MCF7 and HEK293T cells independent of sirtuin 1 (SIRT1) status. MiR-128-2 inhibits the expression of ABCA1, ABCG1 and RXRα directly through a miR-128-2-binding site within their respective 3'untranslated regions. The administration of miR-128-2 leads to decline in the protein and mRNA levels of ABCA1, ABCG1 and RXRα. Conversely, anti-miRNA treatment leads to increased ABCA1, ABCG1 and RXRα expression. The inverse correlation between miR-128-2 and its targets viz. ABCA1 and ABCG1 was also established during high-fat diet in different mice tissues. Our data show that cholesterol efflux is attenuated by miR-128-2 overexpression and, conversely, stimulated by miR-128-2 silencing. Further, we also observed the induction of ER stress response by miR-128-2. In this study, we provide the first evidence of miR-128-2 to be a new regulator of cholesterol homeostasis. Our study shows dual role of miR-128-2, as a pro-apoptotic molecule as well as a regulator of cholesterol homeostasis.
First principles theoretical studies of the atomic and electronic structure of Pd n (n = 1–7) clusters supported on a TiO2(110) surface, and O2 activation by such clusters, have been carried out ...within a gradient corrected density functional approach. It is shown that the supported Pd n cluster geometries are driven by competing effects including intracluster interactions favoring compact geometries and cluster–support interactions that favor geometries that flatten out in the TiO2(110) surface channel. When exposed to O2, a single Pd atom only activates the O–O bond while all other clusters energetically favor a broken O–O bond. The differing behavior of Pd atom is proposed to originate from the minimal amount of charge transferred from Pd to O2 and its spin excitation energy that also result in its observed lack of reactivity in experiments on CO oxidation. Our studies on Pd n O clusters indicate an inverse correlation between the O binding strength to the cluster and the cluster’s surface stability, which we define as the cluster binding energy to the surface minus the energetic cost of deformation when a Pd n cluster conforms to the TiO2 surface channel. For Pd n O2 (n = 2–7), it is shown that while the first O is adsorbed on the Pd n cluster, the second O occupies a site above a lattice Ti site at the Pd–Ti interface and is indicative of spillover O atoms. The theoretical findings are compared with recent experiments on the structure and oxidation of CO by supported clusters in the presence of O2.
A systematic theoretical study of the equilibrium geometries and total energies of Cr encapsulated in Si clusters reveals that Cr@Si(12) is more stable than its neighbors. The origin of this enhanced ...stability is consistent with the 18-electron sum rule commonly used in the synthesis of stable chemical complexes, and may provide a criterion for a systematic search of magic numbers in metalloinorganic clusters. The 6 mu(B) magnetic moment of the caged Cr atom, the largest among the 3d transition metal atoms, is completely quenched. This effect of caging on the properties of transition metal atoms may lead to the synthesis of novel cluster based materials.
The spectral response of common optoelectronic photodetectors is restricted by a cutoff wavelength limit λc that is related to the activation energy (or bandgap) of the semiconductor structure (or ...material) (Δ) through the relationship λc = hc/Δ. This spectral rule dominates device design and intrinsically limits the long-wavelength response of a semiconductor photodetector. Here, we report a new, long-wavelength photodetection principle based on a hot-cold hole energy transfer mechanism that overcomes this spectral limit. Hot carriers injected into a semiconductor structure interact with cold carriers and excite them to higher energy states. This enables a very long-wavelength infrared response. In our experiments, we observe a response up to 55 µm, which is tunable by varying the degree of hot-hole injection, for a GaAs/AlGaAs sample with Δ = 0.32 eV (equivalent to 3.9 µm in wavelength).
Summary
Background
Clostridium difficile infection (CDI) is associated with increased mortality in inflammatory bowel disease (IBD), but the risk of colectomy is variable and has not been adequately ...studied.
Aim
To perform a systematic review and meta‐analysis to assess the impact of CDI on colectomy risk in IBD.
Methods
Multiple databases were searched systematically for observational studies reporting colectomy risk in IBD, stratified by the presence of CDI, and the duration of follow‐up (short term 3 months, and long term at least 1 year). Weighted summary estimates were calculated using generalised inverse variance with random‐effects model. Study quality was assessed using the Newcastle–Ottawa scale.
Results
Twelve observational studies were identified and included 35 057 IBD patients with CDI, and 929 259 without CDI. CDI did not increase the short‐term colectomy risk in IBD patients overall (10 studies) (OR: 1.35; 95% CI: 0.68–2.67), or in patients with ulcerative colitis (nine studies) (OR: 1.20; 95% CI: 0.39–3.76). In contrast, CDI was associated with higher long‐term colectomy risk in patients with IBD overall (five studies) (OR: 2.23; 95% CI: 1.18–4.21), and in patients with ulcerative colitis (four studies) (OR: 2.96; 95% CI: 1.19–7.34). The results were stable in subgroups stratified by recruitment period, hospitalisation status and geographical location. All studies were at least of moderate quality. The results were limited in the ability to compare IBD severity and the type of anti‐microbial therapy.
Conclusion
Based on 12 observational studies with at least moderate quality, Clostridium difficile infection appears to increase colectomy risk in IBD in the long‐ but not short‐ term.
Linked ContentThis article is linked to Nelson and Tsai paper. To view this article visit https://doi.org/10.1111/apt.14039.
To accelerate the process of decomposition using consortia of thermophilic ligno-cellulolytic fungi, different crop residues viz. sorghum (SG), soybean (SS), maize (MS), sugarcane (SC), cotton (CS) ...and pigeon pea (PS) with a varied C:N ratio and sawdust (SD) having high lignin content were collected and used for decomposition process. Compost quality assessed by evaluating different maturity and stability indices at five succeeding stages first mesophilic (M1), thermophilic (T), second mesophilic (M2), cooling (C) and humification (H). A significant reduction was observed in the C:N ratio, biodegradability index, nitrification index, ratio of water-soluble carbon to organic nitrogen (WSC/Org.N) with an increase in concomitant over time while Ash (%), organic matter loss (%), CEC/TOC ratio, cellulose biodegradation ratio (BR) and lignin/cellulose ratio were significantly increased with time. By correlation study, biodegradability index (BI) and fluorescein diacetate (FDA) hydrolysis emerged as the most suitable compost maturity and stability parameters, respectively. Principal component analysis (PCA) results confirmed that BI, BR, WSC/Org. N and FDA can be regarded as key indicators for assessing compost quality. Our findings conclude that fungal consortia of Tricoderma viride, Rhizomucor pusillus, Aspergillus awamori and Aspergillus flavus can accelerate decomposition time from 8 to 12 months (which is normal farming practice) to 120 days.
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•Identified novel fungal consortia for rapid composting.•Assessed maturity and stability indices at five succeeding stages of decomposition.•Derived novel key indicators of rapid compost quality assessment.
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