In Situ Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) Study of Formaldehyde Adsorption and Reactions on Pd-Doped Nano-gamma-Fe2O3 Films

Palladium-doped nano-gamma-Fe2O3 films were printed on Al2O3 substrates by screen printing injecting hybrid technology. X-ray diffraction and scanning electron microscopy techniques were used to characterize the phase structures and morphologies of the films, respectively. The sensitivity of the films to 100 ppm formaldehyde in air was investigated. The surface adsorption and reaction process between Pd-doped nano-gamma-Fe2O3 films and formaldehyde was studied by in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) at different temperatures. Dioxymethylene, formate ions, polyoxymethylene, and adsorbed formaldehyde were detected when the Pd-doped nano-gamma-Fe2O3 films were exposed to 100 ppm formaldehyde at different temperatures. A possible mechanism of the reaction process is discussed

Prevalence, Predictors and Mechanisms of Steam Pops in Ablation Index-Guided High-Power Pulmonary Vein Isolation

Despite the good cooling effect of the contact-force porous catheter, the risk of steam pops (SP) remains one of the major concerns in high-power circumferential pulmonary vein isolation (CPVI). This study aimed to investigate the prevalence, predictors and possible mechanisms of SPs in CPVI. Patients experiencing SPs in de novo high-power CPVI were 1:3 matched by non-SP patients with gender, age (±5 years) and left atrial diameter (LAD) (±5 mm) to compare the ablation parameters of SP and non-SP lesions. Catheter tip displacement (Tipdisp) was compared between “edge-of-ridge” and “PV-side-of-ridge” placement at anterior and roof segments of the left pulmonary vein (PV). SPs occurred in 11 (1.57%) of 701 patients, including 6 at the antero-superior left PV, 2 at the roof, 1 at the postero-superior left PV, 1 at the bottom left PV and 1 at the antero-superior aspect of the right PV. There was significantly shorter RF delivery duration (13.9 ± 6.3 vs. 23.3 ± 6.0 s), greater Δimpedance (17.6 ± 6.7 vs. 6.7 ± 4.1 Ω) and lower ablation index (357.7 ± 68.8 vs. 430.2 ± 30.7) in SP patients than those in non-SP patients. Δimpedance >12 Ω during ablation could predict SP occurrence. Tipdisp was greater in “PV-side-of-ridge” than that in “edge-of -ridge” placement (3.2 ± 1.6 mm vs. 2.0 ± 0.8 mm) at antero-superior and roof segments of the left PV. The prevalence of SP was 1.57% in high-power CPVI procedures, with the most common site at the antero-superior segment of the left PV. Δimpedance was a significant predictor of SP occurrence. “PV-side-of-ridge” ablation at antero-superior and roof segments of left PV might predispose to SP occurrence due to excessive tissue coverage

In situ diffuse reflectance infrared Fourier transform spectroscopy study of formaldehyde adsorption and reactions on nano gamma-Fe2O3 films

The nano gamma-Fe2O3 films gas sensor was fabricated by the screen printing technology. The phase structures and morphologies of nano gamma-Fe2O3 films were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), respectively. The gas sensitivity of the films to 100 ppm formaldehyde was investigated. The surface adsorption and reaction process between nano gamma-Fe2O3 films and formaldehyde was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) method at different temperatures. DRIFTS results showed that dioxymethylene, formate ions, polyoxymethylene and molecularly formaldehyde surface species were detected when the nano gamma-Fe2O3 films exposed to 100 ppm formaldehyde at different temperatures. A possible mechanism of the reaction process was discussed. (c) 2013 Elsevier B.V. All rights reserved

Development of a detection chip for major pathogenic drug-resistant genes and drug targets in bovine respiratory system diseases

Bovine respiratory disease (BRD) is a significant veterinary challenge, often exacerbated by pathogen resistance, hindering effective treatment. Traditional testing methods for primary pathogens – Mycoplasma bovis, Pasteurella multocida, and Mannheimia haemolytica – are notably time-consuming and lack the rapidity required for effective clinical decision-making. This study introduces a TaqMan MGB probe detection chip, utilizing fluorescent quantitative PCR, targeting key BRD pathogens and associated drug-resistant genes and sites. We developed 94 specific probes and primers, embedded into a detection chip, demonstrating notable specificity, repeatability, and sensitivity, reducing testing time to under 1 h. Additionally, we formulated probes to detect mutations in the quinolone resistance-determining region, associated with fluoroquinolone resistance in BRD pathogens. The chip exhibited robust sensitivity and specificity, enabling rapid detection of drug-resistant mutations in clinical samples. This methodology significantly expedites the diagnostic process for BRD and sensitive drug screening, presenting a practical advancement in the field

The Long-Acting Serine Protease Inhibitor mPEG-SPA-MDSPI16 Alleviates LPS-Induced Acute Lung Injury

Anti-inflammatory drugs have become the second-largest class of common drugs after anti-infective drugs in animal clinical care worldwide and are often combined with other drugs to treat fever and viral diseases caused by various factors. In our previous study, a novel serine protease inhibitor-encoding gene (MDSPI16) with improved anti-inflammatory activity was selected from a constructed suppressive subducted hybridization library of housefly larvae. This protein could easily induce an immune response in animals and had a short half-life, which limited its wide application in the clinic. Thus, in this study, mPEG-succinimidyl propionate (mPEG-SPA, Mw = 5 kDa) was used to molecularly modify the MDSPI16 protein, and the modified product mPEG-SPA-MDSPI16, which strongly inhibited elastase production, was purified. It had good stability and safety, low immunogenicity, and a long half-life, and the IC50 for elastase was 86 nM. mPEG-SPA-MDSPI16 effectively inhibited the expression of neutrophil elastase and decreased ROS levels. Moreover, mPEG-SPA-MDSPI16 exerted anti-inflammatory effects by inhibiting activation of the NF-κB signaling pathway and the MAPK signaling pathway in neutrophils. It also exerted therapeutic effects on a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. In summary, mPEG-SPA-MDSPI16 is a novel anti-inflammatory protein modified with PEG that has the advantages of safety, nontoxicity, improved stability, and strong anti-inflammatory activity in vivo and in vitro and is expected to become an effective anti-inflammatory drug

An Antibacterial Peptide with High Resistance to Trypsin Obtained by Substituting d-Amino Acids for Trypsin Cleavage Sites

The poor stability of antibacterial peptide to protease limits its clinical application. Among these limitations, trypsin mainly exists in digestive tract, which is an insurmountable obstacle to orally delivered peptides. OM19R is a random curly polyproline cationic antimicrobial peptide, which has high antibacterial activity against some gram-negative bacteria, but its stability against pancreatin is poor. According to the structure-activity relationship of OM19R, all cationic amino acid residues (l-arginine and l-lysine) at the trypsin cleavage sites were replaced with corresponding d-amino acid residues to obtain the designed peptide OM19D, which not only maintained its antibacterial activity but also enhanced the stability of trypsin. Proceeding high concentrations of trypsin and long-time (such as 10 mg/mL, 8 h) treatment, it still had high antibacterial activity (MIC = 16–32 µg/mL). In addition, OM19D also showed high stability to serum, plasma and other environmental factors. It is similar to its parent peptide in secondary structure and mechanism of action. Therefore, this strategy is beneficial to improve the protease stability of antibacterial peptides

Antibiotic resistance of probiotics isolated from Chinese corn stover silage

ABSTRACTOne of the most important drivers of the emergence of antimicrobial resistance is the irrational usage of antibiotics. But alongside some indirect sources such as feeding Chinese corn stover silage could also transmit resistant genes to animals. This study was aimed at assessing the antibiotic resistance phenotypes, drug resistance genes and mediated drug resistance mechanisms. A total of 37 isolates were obtained by selective medium and identified by 16S rDNA sequencing including Lactobacillus acidophilus (n = 3), Lactobacillus amylovorus (n = 4), Weissella confusa (n = 3), Acetobacter pasteurianus (n = 9), Lactobacillus buchneri (n = 6), Enterococcus faecium (n = 8) and Lactobacillus reuteri (n = 4). Antimicrobial resistance of all isolates to 12 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, erythromycin, clindamycin, kanamycin, streptomycin, levofloxacin and ciprofloxacin was observed. The presence of relevant resistance genes was examined by PCR, and the genes pbp5, blaZ, bla TEM, mecA, mexI, tetW, ermB, msrA, msrC, ermC, vatE, aacA-aphD, aphA1, aadA1, aadA2 and vanX were detected. All the isolated strains had multiple drug resistance, and harboured related drug-resistant genes; therefore, the use of probiotics in animal feed should be standardized to reduce the risks of horizontal transmission of drug resistance genes to animal products and human population

Image_1_Impact of technical aspects of vein of Marshall ethanol infusion on mitral isthmus block for persistent atrial fibrillation ablation.tif

AimsEthanol infusion into the VOM (EIVOM) adjunctive to radiofrequency catheter ablation (RFCA) was a novel approach facilitating mitral isthmus (MIth) block for persistent atrial fibrillation (PeAF); However, there were remarkable disparities in its technical aspects. This study aimed to evaluate the impact of EIVOM technical aspects on acute MIth block.MethodsEighty consecutive patients (63 males, average age 66.4 ± 8.6 years) undergoing de novo PeAF ablation were assigned to different groups. The procedural parameters in “EIVOM first” (n = 13) or “RFCA first” (n = 13) as well as small dose ([SD], ≤4 ml, n = 26) or big dose ([BD], >4 ml, n = 54) approaches were analyzed to identify the predictors for acute MIth block.ResultsCompared with the “EIVOM first” approach, the “RFCA first” approach was associated with longer procedural and MIth ablation time (134 ± 27 min vs. 112 ± 17 min; 14.9 ± 5.5 min vs. 9.3 ± 5.1 min, both P 5.75 ml independently predicted successful MIth block (OR: 0.428, 95% CI: 0.219–0.839, P = 0.01).ConclusionsDespite the comparable effectiveness on MIth block, the “EIVOM first” approach was associated with shorter procedural and MIth ablation time than the “RFCA first” approach. The ethanol dose in EIVOM was an independent predictor for MIth block.</p

High Cell Selectivity and Bactericidal Mechanism of Symmetric Peptides Centered on d-Pro–Gly Pairs

Antimicrobial peptides (AMPs) have a unique action mechanism that can help to solve global problems in antibiotic resistance. However, their low therapeutic index and poor stability seriously hamper their development as therapeutic agents. In order to overcome these problems, we designed peptides based on the sequence template XXRXXRRzzRRXXRXX-NH2, where X represents a hydrophobic amino acid like Phe (F), Ile (I), and Leu (L), while zz represents Gly&ndash;Gly (GG) or d-Pro&ndash;Gly (pG). Showing effective antimicrobial activity against Gram-negative bacteria and low toxicity, designed peptides had a tendency to form an &alpha;-helical structure in membrane-mimetic environments. Among them, peptide LRpG (X: L, zz: pG) showed the highest geometric mean average treatment index (GMTI = 73.1), better salt, temperature and pH stability, and an additive effect with conventional antibiotics. Peptide LRpG played the role of anti-Gram-negative bacteria through destroying the cell membrane. In addition, peptide LRpG also exhibited an anti-inflammatory activity by effectively neutralizing endotoxin. Briefly, peptide LRpG has the potential to serve as a therapeutic agent to reduce antibiotic resistance owing to its high therapeutic index and great stability