Search

Materials having nonlinear optical (NLO) properties have shown hi-tech uses in a variety of modern fields including telecommunications, solid-state physics, laser optics and more recently in quantum computing. The current study offers a comprehensive computational analysis of the chalcone compounds designed through halogens and traditional acceptors. The molecular structure and electronic properties of parent compound (E)-1-(4-aminophenyl)-3-(3-chlorophenyl)prop-2-en-1-one (C1) were quantum chemically simulated and found in good agreement with experimentally reported results. The new chalcone compounds C2–C8 were also proposed by substituting chlorine with acceptors (F, Br, CH3, CF3, COOH, CN and NO2) into a benzene ring with fixed donor (aniline) and a π-bridge (acrolein). DFT and TD-DFT calculations were employed to shed light on charge transfer properties, promising structures, density of states plots and NLO characteristics. The substitution with acceptors effectively modified the structures with halogens and nonhalogen groups, resulting in improved NLO characteristics. A striking NLO response was seen in all proposed compounds. It is interesting to note that the NLO characteristics of C2–C3 and C4–C8 have been significantly improved by the intramolecular charge transfer (ICT) process with β// value of 18.30 × 10−30 esu. However, C7 showed the highest < γ > values of 106.6 × 10−36. Among C1–C8 compounds, C8 had a narrower HOMO–LUMO energy gap, facilitating efficient electronic excitations and resonance enhancement which led to an improved NLO response. TDM analysis confirms the intramolecular charge transfer (ICT) in C1–C8 compounds due to the successful migration of charge from donor to acceptor via π-bridge. The current study intrigues scientific interest regarding the formation of chalcone-based appealing NLO compounds that may be useful in recent high-tech applications. [ABSTRACT FROM AUTHOR]

Cervical cancer accounts for most deaths due to cancer in women, majorly in developing nations. The culprit behind this disease is the human papillomavirus (HPV) which accounts for more than 90% of cervical cancer cases. The viral strains produce proteins that favor the knocking down of the apoptosis process and continuous growth of cells in the cervix leading to tumor growth. Proangiogenic growth factors, such as fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), angiopoietins, and other endothelial growth factors (EGF), are secreted by tumor cells and the surrounding microenvironment, which further advances the development of cancer. The extracellular domain of receptor tyrosine kinases is employed by ligands (like VEGF and EGF) to engage and activate them by inducing receptor dimerization, which facilitates the cascade impact of these factors. The tyrosine kinase domains of each receptor autophosphorylate each other, activating the receptor and initiating signaling cascades that promote angiogenesis, migration, proliferation, and survival of endothelial cells. Cancer cells benefit from its modified signaling pathways, which cause oncogenic activation. Upon early cervical cancer detection, the second-line therapy strategy involves blocking the signaling pathways with VEGF and small molecule tyrosine kinase inhibitors (TKIs). This review paper highlights the genesis of cervical cancer and combating it using VEGF and tyrosine kinase inhibitors by delving into the details of the currently available inhibitors. Further, we have discussed the inhibitor molecules that are currently in various phases of clinical trials. This paper will surely enhance the understanding of cervical cancer and its treatment approaches and what further interventions can be done to alleviate the disease currently serving as a major health burden in the developing world. [ABSTRACT FROM AUTHOR]

The article discusses the profound impact of advancements in computing and software on theoretical simulations, marking a transformative era in computational chemistry. Focused on theoretical coordination chemistry, it delves into the historical context and underscores the contemporary importance of computational methods. Coordination materials, involving metal atoms surrounded by ligands, are highlighted for their pivotal roles across scientific disciplines. The manipulation of ligands and metal ions within these compounds offers diverse functionalities, from catalytic modifications to enhancing oxygen transport in biological systems. The comprehensive review explores the basics of coordination materials, detailing examples across various categories. Theoretical approaches, including quantum mechanics methods like density functional theory (DFT) and Monte Carlo simulations, are thoroughly examined. The article emphasizes crystallography techniques for Metal-Organic Frameworks (MOFs) and concludes by emphasizing the exponential growth in computing power, making modeling and simulation indispensable in molecular and material research. The development of an integrated computational strategy rooted in DFT is highlighted as a crucial advancement, bridging precision and computational practicality. This holistic approach advances understanding in coordination chemistry and nanostructured materials, paving the way for innovative applications and discoveries. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is a significant concern worldwide; meanwhile, the impact of 3rd generation cephalosporin (3GC) antibiotics on the microbial communities of cattle and resistance within these communities is largely unknown. The objectives of this study were to determine the effects of two-dose ceftiofur crystalline-free acid (2-CCFA) treatment on the fecal microbiota and on the quantities of second-and third-generation cephalosporin, fluoroquinolone, and macrolide resistance genes in Holstein-Friesian dairy cows in the southwestern United States. Across three dairy farms, 124 matched pairs of cows were enrolled in a longitudinal study. Following the product label regimen, CCFA was administered on days 0 and 3 to cows diagnosed with postpartum metritis. Healthy cows were pair-matched based on lactation number and calving date. Fecal samples were collected on days 0, 6, and 16 and pooled in groups of 4 (n = 192) by farm, day, and treatment group for community DNA extraction. The characterization of community DNA included real-time PCR (qPCR) to quantify the following antibiotic resistance genes: blaCMY-2, blaCTX-M, mphA, qnrB19, and the highly conserved 16S rRNA back-calculated to gene copies per gram of feces. Additionally, 16S rRNA amplicon sequencing and metagenomics analyses were used to determine differences in bacterial community composition by treatment, day, and farm. Overall, blaCMY-2 gene copies per gram of feces increased significantly (p ≤ 0.05) in the treated group compared to the untreated group on day 6 and remained elevated on day 16. However, blaCTX-M, mphA, and qnrB19 gene quantities did not differ significantly (p ≥ 0.05) between treatment groups, days, or farms, suggesting a cephamycinase-specific enhancement in cows on these farms. Perhaps unexpectedly, 16S rRNA amplicon metagenomic analyses showed that the fecal bacterial communities from treated animals on day 6 had significantly greater (p ≤ 0.05) alpha and beta diversity than the untreated group. Two-dose ceftiofur treatment in dairy cows with metritis elevates cephamycinase gene quantities among all fecal bacteria while paradoxically increasing microbial diversity. [ABSTRACT FROM AUTHOR]

We systematically study the optical and nonlinear optical (NLO) properties of various cyclopentadithiophene (CPDT) derivatives using quantum chemical calculations. The designed derivatives are classified into three classes and each class have three types of derivatives as a, b and c. For example, compounds 1a, 2a, and 3a are formed by substituting nitrophenyl at the terminal positions of 2,6-diphenyl-4 H-cyclopenta[2,1-b:3,4-b′]dithiophene at the terminal positions to design V-shaped (Λ-shaped) compounds and similar pattered were adopted for other classes. The dipole moment (µ), linear isotropic and anisotropic polarizability along with second-order and third-order NLO polarizability are computed by applying density functional theory (DFT) methods at PBE1PBE/6-311G** level of theory. Among all the derivatives, 3a and 1a shows the maximum linear isotropic (αiso) and anisotropic (αaniso) polarizability of 120.4 × 10−24 and 161.4 × 10−24 esu respectively. The noteworthy effect of incorporating different electron donor and acceptor moieties to the overall NLO polarizability is observed. The largest average second-order NLO polarizability value is observed 92.59 × 10−30 esu for system 1a. The β// amplitude of 1a is ~ 1.5 to 11 times more as compared to other derivatives. Additionally, the nonlinear anisotropy of β// amplitudes is also seen significantly larger ranging from 4.96 to 129.63 which is due to the V-shaped structure of designed compounds. While on the other hand, some compounds shows the third-order NLO polarizability amplitudes which are ranging in thousands including 4107 × 10−36, 5020 × 10−36, 5857 × 10−36, 6412 × 10−36, 6700 × 10−36 and 9057 × 10−36 esu for compounds 1b, 2b, 3a, 2a, 3b and 1a, respectively. Strikingly, the β// and <γ> amplitudes of compound 1a are ~ 14 and ~ 1242 times greater than that of standard para-nitroaniline (prototype NLO molecule), respectively, as computed at same PBE1PBE/6-311G** method. The TD-DFT calculations are also performed to see origin of larger NLO polarizabilities. The molecular electrostatic potential maps and frontier molecular orbitals are drawn to get further insight into the structure-NLO property relationship of newly designed CPDT derivatives. Hence, we considered that the current investigation will interest the researchers to further explore the optical and NLO applications of these CPDT derivatives. [ABSTRACT FROM AUTHOR]

The possibility of tuning the chemical structures of oligothiophenes offers various applications in designing of optoelectronics and nonlinear optical (NLO) materials. In the current study, we report a computational study of quinoidal oligothiophenes to explore the influence of type of π-conjugation chains and nature of terminal acceptor groups to push their linear (α) and third-order nonlinear optical (γ) polarizability to a robust limit. The ground-state molecular geometries of designed compounds 1–8 are optimized using DFT at the M06/6-311G** level of theory. Among all the designed compounds, the largest linear isotropic (αiso) and anisotropic (αaniso) polarizability values of 342.7 × 10–36 and 765.6 × 10–36 esu are shown by compound 8 owing to its excellent electronic connection between central thiophene rings and terminal acceptor groups. Similarly, the highest average static third-order nonlinear optical (NLO) polarizability < γ > amplitude of 7448 × 10–36 esu is shown by compound 8 which is ~ 1319, ~ 103, ~ 21, ~ 77, ~ 40, ~ 28, and ~ 13 times greater as compared to compounds 1–7, respectively. Strikingly, comparative analysis of < γ > between compound 8 and p-NA (prototype NLO molecule) reveals that < γ > amplitude of compound 8 is 1021 times more than that of p-NA at the same M06/6-311G** methodology as calculated in current investigation. Remarkably, the large difference between < γ > values of compound 8 and p-NA designates significant potential of our designed compound for various NLO applications. Furthermore, TD-DFT computations indicate that the greater NLO response of compound 8 is because of its higher oscillator strength and lower transition energy in contrast to other designed molecular systems. Moreover, TD-DFT calculations are also used to investigate structure-NLO property relations in terms of frontier molecular orbitals (FMOs), the density of states (DOS), molecular electrostatic potential (MEP), and transition density matrix (TDM) parameters. We believe the current design will instigate the materials science community for such novel motifs with efficient optoelectronic and NLO properties. [ABSTRACT FROM AUTHOR]

In the present investigation, a variety of quinoidal oligomers with different arrangements and distinctive fused shapes of thiophene rings are studied. These quinoidal oligomers were further explored for the systematic heteroatom substitution using state-of-art quantum computational methods. The substitution of S atoms by O and N in oligomer compounds is done to see change in optical and nonlinear optical properties while moving from series 1 to series 4. The substitution of oligomer chain shows a significant effect on linear polarizability, first and second hyperpolarizabilities as calculated at M06/6-311G** level of theory. All the studied compounds showed relatively average first hyperpolarizability while reasonably large second hyperpolarizability. Among all the studied compounds, the largest second hyperpolarizability of 1003 × 10–36 esu is shown by 4c which is ~ 138 times greater than standard p-NA molecule. Interestingly, TD-DFT analysis indicates that the series 4 has larger oscillator strengths and lower transition energy values which contributes to its enlarged amplitude of second hyperpolarizability response. Furthermore, the transition density matrix, frontier molecular orbitals and molecular electrostatic potential diagrams showed that the charge transfer occurs from oligomer chain to cyanide groups and this charge transfer is highly dependent on the substitution patterns. The density of states diagrams of the selected class of compounds 4a, 4b and 4c show that 4c has significant partial contributions of oligomer chain in HOMO–LUMO orbitals. Thus, the comparative study of four series of compounds indicates not only the importance of shape and size of oligomer molecules but also indicates the importance of heteroatom substitutions to attain a vigorous second hyperpolarizability response for their potential use in optoelectronic and NLO applications. [ABSTRACT FROM AUTHOR]

Background: Tylosin is commonly prescribed to dogs with diarrhea. Orally administered antibiotics may alter the intestinal microbiota, which is responsible for crucial key bile acid (BA) biotransformation reactions. Objectives: To prospectively evaluate the impact of tylosin administration on fecal microbiota and unconjugated bile acids (UBAs) over time. Animals: Sixteen healthy adult dogs. Methods: Prospective, randomized controlled clinical trial. Dogs were randomized to receive 20 mg/kg of tylosin or a placebo capsule PO q12h for 7 days while undergoing daily fecal scoring. Fecal samples were collected on days 0, 7, 21, and 63. The microbiota was assessed using quantitative PCR and 16S rRNA gene sequencing. Unconjugated BAs were assessed using gas chromatography‐mass spectrometry (GC‐MS). Results: Fecal scores were unchanged during placebo and tylosin administration. In the placebo group, no significant changes were observed in fecal microbiota or UBA concentrations. Day 7 samples from tylosin‐exposed dogs exhibited decreased bacterial diversity (observed species, Chao1, Shannon, P < .001) characterized by decreases in anaerobes Fusobacteriaceae (linear discriminant analysis [LDA] score, 5.03) and Veillonellaceae (LDA score, 4.85). Primary UBA concentrations were increased at day 21 (median, [range]; 7.42, [0.67‐18.77] μg/kg; P =.04) and day 63 (3.49 [0‐28.43] μg/kg; P =.02) compared to day 0 (.14 [.03‐1.19] μg/kg) in dogs receiving tylosin. At day 63, bacterial taxa were not significantly different compared to day 0, but the extent of microbial recovery was individualized. Conclusions and Clinical Importance: Tylosin causes fecal dysbiosis in healthy dogs with corresponding shifts in fecal UBAs. Changes did not uniformly resolve after discontinuation of tylosin. [ABSTRACT FROM AUTHOR]

Introduction: The impact of probiotics on dogs with acute hemorrhagic diarrhea syndrome (AHDS) has not been evaluated so far. The study aim was to assess the effect of probiotic treatment on the clinical course, intestinal microbiome, and toxigenic Clostridium perfringens in dogs with AHDS in a prospective, placebo-controlled, blinded trial. Methods: Twenty-five dogs with AHDS with no signs of sepsis were randomly divided into a probiotic (PRO; Visbiome, ExeGi Pharma) and placebo group (PLAC). Treatment was administered for 21 days without antibiotics. Clinical signs were evaluated daily from day 0 to day 8. Key bacterial taxa, C. perfringens encoding NetF toxin and enterotoxin were assessed on days 0, 7, 21. Results: Both groups showed a rapid clinical improvement. In PRO a significant clinical recovery was observed on day 3 (p = 0.008), while in PLAC it was observed on day 4 (p = 0.002) compared to day 0. Abundance of Blautia (p<0.001) and Faecalibacterium (p = 0.035) was significantly higher in PRO on day 7 compared to day 0, while in PLAC the abundance of Faecalibacterium was not significantly higher on any study day and Blautia (p = 0.016) was only significantly higher on day 21 compared to day 0. Abundance of C. perfringens was significantly lower on day 7 (p = 0.011) compared to day 0 in PRO but not in PLAC. Enterotoxin genes were significantly lower in PRO on day 21 (p = 0.028) compared to PLAC. Fecal samples of 57% of all dogs were positive for netF toxin genes on day 0 and the abundance was significantly lower on day 7 compared to day 0 in PRO (p = 0.016) and PLAC (p = 0.031). Conclusion: The probiotic treatment was associated with an accelerated normalization of the intestinal microbiome. Dogs with aseptic AHDS showed a rapid decrease of netF toxin genes and fast clinical recovery in both groups under symptomatic treatment without antibiotics. [ABSTRACT FROM AUTHOR]

We investigated wild migratory birds faecal swabs for extended-spectrum β-lactamases-producing Klebsiella pneumoniae (ESBL- K. pneumoniae) from wetland habitats in Pakistan. ESBL- K. pneumoniae were analysed for MDR phenotype, ESBL genotype and genetic diversity. A total of 13 (8.6%) ESBL- K. pneumoniae were recovered. Of these, 8 (61%) isolates were MDR. DNA sequencing confirmed bla as the dominant ESBL genotype. BOX-PCR fingerprints showed most of the isolates are unrelated. This study is the first to report the wildlife contamination of CTX-M-15-producing K. pneumoniae in Pakistan. Due to long-range migration, these birds could be responsible for trans-boundary spread of multidrug-resistant bacteria. [ABSTRACT FROM AUTHOR]

Following publication of this article [[1]], the authors provide revised text to clarify the composition of the probiotic mixture, sold under the brand Vivomixx in Continental Europe, which was used in the study. (ZIP) Reference 1 Ziese A-L, Suchodolski JS, Hartmann K, Busch K, Anderson A, Sarwar F, et al. (2018) Effect of probiotic treatment on the clinical course, intestinal microbiome, and toxigenic I Clostridium perfringens i in dogs with acute hemorrhagic diarrhea. [Extracted from the article]

Glomangiopericytoma is a rare vascular neoplasm characterised by a pattern of prominent perivascular growth with myoid phenotype. It is categorised as a borderline low-malignancy tumour by WHO and accounts for less than 0.5% of all sinonasal tumours. After curative resection, patients of glomangiopericytoma need long-term endoscopic follow-up due to high risk of recurrence. We report a case of a 23-year-old man complaining of nasal obstruction off and on and frequent epistaxis. A reddish mass in the right nasal cavity was observed on endoscopy and treated with endoscopic excision. Biopsy revealed this to be glomangiopericytoma arising from the septum of right nasal cavity, which was excised in toto with endonasal endoscopic approach using diode laser. [ABSTRACT FROM AUTHOR]

Extrapulmonary tuberculosis is a rather uncommon and potentially challenging phenomenon. Such manifestation, particularly in the scenario of a late postoperative period, is extremely rare and requires a high index of suspicion, prompt diagnosis and appropriate treatment. We present the case scenario of a patient with history of successfully treated pulmonary tuberculosis many years earlier, without any signs of recurrence, who developed primary nasal septal tuberculosis after undergoing septoplasty to correct his septal deviation. His postoperative course remained uneventful for 4 months. He then presented with a spontaneous nasal septal abscess, which proved to be tubercular in nature on investigations. Appropriate diagnosis was established, and the patient was treated successfully with antituberculous therapy. Recurrent tuberculosis may present a diagnostic challenge for healthcare professionals. Only a high index of suspicion, modern diagnostic tools and institution of appropriate treatment including surgical intervention as required will ensure a promising outcome. [ABSTRACT FROM AUTHOR]