Computational insights into popsilicene as a new planar silicon allotrope composed of 5-8-5 rings.

Silicon-based two-dimensional (2D) materials have garnered significant attention due to their unique properties and potential applications in electronics, optoelectronics, and other advanced technologies. Here, we present a comprehensive investigation of a novel silicon allotrope, Popsilicene (Pop-Si), derived from the structure of Popgraphene. Using density functional theory and ab initio molecular dynamics simulations, we explore the thermal stability, mechanical and electronic properties, and optical characteristics of Pop-Si. Our results demonstrate that Pop-Si exhibits good thermal stability at 1000 K. Electronic structure calculations reveal that Pop-Si is metallic, with a high density of states at the Fermi level. Furthermore, our analysis of the optical properties indicates that Pop-Si has pronounced UV-Vis optical activity, making it a promising candidate for optoelectronic devices. Mechanical property assessments show that Pop-Si has Young's modulus ranging from 10 to 92 GPa and a Poisson's ratio of 0.95. These results combined suggest its potential for practical applications.

Immune response in nonspecific mastitis: What can it tell us?

We analyzed a large number of immune response parameters from quarter milk samples with distinct bacteriological and quarter somatic cell count (qSCC) statuses. Furthermore, we sought to explore and identify displayed immune response patterns in milk samples from mammary glands with nonspecific mastitis. Thus, 92 quarter milk samples from 28 cows were stratified into 4 groups, as follows: (1) 49 culture-negative control quarters with a low qSCC (<1 × 105 cells/mL) from 19 dairy cows (so-called healthy quarters); (2) 15 culture-negative quarters with high qSCC (>2 × 105 cells/mL; so-called quarters with nonspecific mastitis) from 10 dairy cows; (3) 8 culture-positive quarters with low qSCC (noninflammatory quarters with low qSCC) from 5 dairy cows; and (4) 20 culture-positive quarters with high qSCC (so-called truly infected quarters) from 8 dairy cows. Using flow cytometry, we evaluated the percentage of milk neutrophils and their viability, intracellular reactive oxygen species production, phagocytosis, and the expression of CD62L, CD11b, and CD44 for each of the 4 quarter strata. Furthermore, the percentage of monocyte/macrophages, B cells, and T lymphocyte subsets were evaluated by flow cytometry. Milk samples from bacteriologically negative quarters (both with a low and elevated qSCC) had a lower qSCC than those with bacteriologically positive outcomes (both with a low and elevated qSCC). As expected, the healthy quarters showed the lowest percentage of neutrophils and also showed a higher percentage of milk monocytes/macrophages and lower percentage of T lymphocytes than truly infected quarters. The most prominent result of the present study is that quarters with nonspecific mastitis showed the highest percentage of milk CD4+ T lymphocytes. The healthy quarters had a lower percentage of apoptotic neutrophils than noninflammatory and truly infected quarters, although it did not differ from those from the quarters with nonspecific mastitis. Our study supports the role of differential cell counting in the diagnosis of mastitis, as the milk leukocyte populations markedly fluctuate under healthy and inflammatory conditions. Furthermore, an increase in milk CD4+ T cells was associated with nonspecific mastitis, suggesting an increase in this leukocyte subpopulation is correlated with low bacterial shedding. Our study allows us to go further in our understanding of mammary gland immunity, providing further insights on potential protective mammary gland immunity, which we hypothesize can open new avenues for the development of novel targets that can promote bovine udder health.

Inactivation of milk-borne pathogens by blue light exposure.

Food safety and quality management play a pivotal role in the dairy industry. Milk is a highly nutritious food that also provides an excellent medium for growth of pathogenic microorganisms. Thus, dairy industry focuses most of their processes and costs on keeping contamination levels as low as possible. Thermal processes for microbial decontamination may be effective; however, they cannot provide excellent organoleptic, nutritional, and decontamination properties simultaneously. In this scenario, microbial inactivation by exposure to blue light is a promising alternative method in the food industry due to its intrinsic antimicrobial properties free of any thermal effect. Therefore, this study aimed to determine the inactivation kinetics induced by blue light (λ = 413 nm) against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium, and Mycobacterium fortuitum cells suspended in whole milk or saline solution. We also performed a series of optic spectroscopies to investigate possible degradation of milk components. All species were sensitive to photoinactivation suspended either in saline solution or milk. Inactivation kinetics differs significantly depending on the suspension medium and each species is differently affected. All bacterial species tested presented more than 5 log10 of inactivation within less than 2 h of irradiation (720 J/cm2). Infrared spectroscopy did not reveal any significant alteration in any of the milk constituents (e.g., sugars, proteins, and lipids). Riboflavin (vitamin B2) was the only significantly degraded constituent found. Therefore, we conclude that microbial inactivation performed by blue light presents extraordinary potential for processes in the dairy industry.

Anodal tDCS of the swallowing motor cortex for treatment of dysphagia in multiple sclerosis: a pilot open-label study.

Swallowing difficulties are a common symptom of multiple sclerosis (MS). The early detection and treatment of dysphagia is critical to prevent complications, including poor nutrition, dehydration, and lung infections. Recently, transcranial direct current stimulation (tDCS) has been proven to be effective in ameliorating swallowing problems in stroke patients. In this pilot study, we aimed to assess safety and efficacy of transcranial direct current stimulation (tDCS) in the treatment of dysphagia in MS patients. We screened 30 patients by using the 10-item DYsphagia in MUltiple Sclerosis (DYMUS) questionnaire, and patients at risk for dysphagia underwent a clinical and fiberoptic endoscopic evaluation of swallowing (FEES). Six patients who presented with mild to moderate dysphagia underwent the experimental procedures. These consisted of 5 sessions of anodal tDCS applied in consecutive days over the right swallowing motor cortex. Patients were followed-up at 1 week, 1 month and 3 months after treatment, and changes in the Dysphagia Outcome and Severity Scale (DOSS) score between baseline and post-tDCS were assessed. Our results showed that in all patients, the tDCS treatment determined a mild but significant clinical benefit (one-point improvement in the DOSS score) lasting up to 1 month. In conclusion, our preliminary results show that anodal tDCS has therapeutic potential in the treatment of swallowing problems in patients suffering with MS. However, future double-blind, randomized, and sham-controlled studies are needed to confirm the present findings.

A novel dihydrocoumarin under experimental and theoretical characterization.

Coumarins are natural and synthetic active ingredients widely applied in diverse types of medicinal treatments, such as cancer, inflammation, infection, and enzyme inhibition (monoamine oxidase B). Dihydrocoumarin compounds are of great interest in organic chemistry due to their structural versatilities and, as part of our investigations concerning the structural characterization of small molecules, this work focuses on crystal structure and spectroscopic characterization of the synthesized and crystallized compound 4-(4-methoxyphenyl)-3,4-dihydro-chromen-2-one (C16H14O3). Additionally, a theoretical calculation was performed using density functional theory to analyze the sites where nucleophilic or electrophilic attack took place and to examine the molecular electrostatic potential surface. Throughout all of these calculations, both density functional theory and Car-Parrinello molecular dynamics were performed by fully optimized geometry. The spectroscopic analysis indicated the presence of aromatic carbons and hydrogen atoms, and also the carbonyl and methoxy groups that were confirmed by the crystallographic structure. The C16H14O3 compound has a non-classical intermolecular interaction of type C-H⋅⋅⋅O that drives the molecular arrangement and the crystal packing. Moreover, the main absorbent groups were characterized throughout calculated harmonic vibrational frequencies. Also, natural bond orbital analysis successfully locates the molecular orbital with π-bonding symmetry and the molecular orbital with π* antibonding symmetry. Finally, the gap between highest occupied and lowest unoccupied molecular orbitals implies in a high kinetic stability and low chemical reactivity of title molecule.

Synthesis, characterization, and computational study of the supramolecular arrangement of a novel cinnamic acid derivative.

In this work, we present the synthesis, characterization, and computational study of the supramolecular arrangement of a new cinnamic acid derivative: ethyl-(2E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-prop-2-enoate (EHD). Single crystals of EHD were obtained using ethyl ether as solvent and a slow evaporation technique. Its crystallographic structure, derived from X-ray diffraction experiments, includes a disordered water molecule on the EHD supramolecular structure. This water molecule participates in four O-H···O hydrogen bonds, which are arranged as a centrosymmetric H-bond array with the water at the center. Electronic and structural properties of the isolated EHD molecule and of the EHD molecule in the presence of one water molecule were calculated at the B3LYP/6-311++G(2d,2p) level of theory. These calculations show that the HOMO-LUMO energy gap of EHD decreases upon the introduction of the water molecule, suggesting that EHD becomes a stronger electron acceptor. These results indicate that the water molecule helps to stabilize the crystal structure in this system containing unequal numbers of acceptor and donor atoms. The supramolecular synthon involving the disordered water molecule and the supramolecular features presented here provide new possibilities in the design of functional materials and should also help us to gain a deeper understanding of the processes by which molecules recognize biological targets.

Investigation of the Abstraction and Dissociation Mechanism in the Nitrogen Trifluoride Channels: Combined Post-Hartree-Fock and Transition State Theory Approaches.

The present paper concludes our series of kinetics studies on the reactions involved in the complex mechanism of nitrogen trifluoride decomposition. Two other related reactions that, along with this mechanism, take part in an efficient boron nitride growth process are also investigated. We report results concerning two abstraction reactions, namely NF2 + N ⇄ 2NF and NF3 + NF ⇄ 2NF2, and two dissociations, N2F4 ⇄ 2NF2 and N2F3 ⇄ NF2 + NF. State-of-the-art electronic structure calculations at the CCSD(T)/cc-pVTZ level of theory were considered to determine geometries and frequencies of reactants, products, and transition states. Extrapolation of the energies to the complete basis set limit was used to obtain energies of all the species. We applied transition state theory to compute thermal rate constants including Wigner, Eckart, Bell, and deformed theory corrections in order to take tunneling effects into account. The obtained results are in good agreement with the experimental data available in the literature and are expected to provide a better phenomenological understanding of the NF3 decomposition role in the boron nitride growth for a wide range of temperature values.

Efeito alcalinizante da solução de Ringer com lactato em ovelhas sadias e acidóticas / Alkalinizing effect of lactated Ringer's solution in healthy and acidotic sheep

O estudo teve o objetivo de testar a hipótese de que o efeito alcalinizante da solução de Ringer com lactato (SRL) pode ser maior nos animais portadores de acidose metabólica do que nos sadios, como consequência da necessidade de retorno ao equilíbrio. Seis ovelhas receberam a SRL em volume correspondente a 10% do peso corporal, administrada por infusão contínua intravenosa, durante quatro horas, em duas condições definidas: enquanto eram saudáveis e após a indução experimental de acidose láctica ruminal aguda (ALRA). Amostras de sangue venoso e de urina foram colhidas em quatro momentos: antes do início da infusão, na metade do volume infundido, ao término da infusão e duas horas após. Foram determinados valores de pH sanguíneo e urinário, de pCO2, HCO3 - e BE no sangue, de Na+, K+, Cl-, SID, AG, PPT, Atot e lactato L no plasma, e das excreções fracionadas urinárias de Na+, K+, Cl- e lactato L. A SRL provocou hemodiluição, mas não interferiu nos equilíbrios eletrolítico e acidobase das ovelhas sadias. Apesar de eficaz para reverter a desidratação, não foi capaz de corrigir a acidose metabólica presente após a indução da ALRA.

The aim of this study was to investigate if the alkalinizing effect of lactated Ringer's solution (LRS) is greater in animals with metabolic acidosis than in healthy ones, as a result of the need to restore acid-base balance. LRS was intravenously infused in a volume corresponding to 10% of body weight, continously during four hours, in two definite conditions in the same six ewes: when they were healthy and after experimentally induced acute rumen lactic acidosis (ARLA). Venous blood and urine samples were taken in four moments: before the beginning, in the middle, at the end of the infusion and two hours after. Blood and urine pH, blood pCO2, HCO3 - and BE, and plasma Na+, K+, Cl-, TP and L lactate were measured. Na+, K+, Cl- and L lactate fractional clearance and plasma SID, AG, and Atot were calculated. LRS caused hemodilution but didn't change electrolyte and acid-base balances in healthy ewes. When ewes were affected by ARLA, the infusion of this solution was effective for dehydration reversion but was unable to correct metabolic acidosis.

Chirality of weakly bound complexes: the potential energy surfaces for the hydrogen-peroxide-noble-gas interactions.

We consider the analytical representation of the potential energy surfaces of relevance for the intermolecular dynamics of weakly bound complexes of chiral molecules. In this paper we study the H2O2-Ng (Ng=He, Ne, Ar, Kr, and Xe) systems providing the radial and the angular dependence of the potential energy surface on the relative position of the Ng atom. We accomplish this by introducing an analytical representation which is able to fit the ab initio energies of these complexes in a wide range of geometries. Our analysis sheds light on the role that the enantiomeric forms and the symmetry of the H2O2 molecule play on the resulting barriers and equilibrium geometries. The proposed theoretical framework is useful to study the dynamics of the H2O2 molecule, or other systems involving O-O and S-S bonds, interacting by non-covalent forces with atoms or molecules and to understand how the relative orientation of the O-H bonds changes along collisional events that may lead to a hydrogen bond formation or even to selectivity in chemical reactions.

CO2 adsorption on polar surfaces of ZnO.

Physical and chemical adsorption of CO2 on ZnO surfaces were studied by means of two different implementations of periodic density functional theory. Adsorption energies were computed and compared to values in the literature. In particular, it was found that the calculated equilibrium structure and internuclear distances are in agreement with previous work. CO2 adsorption was analyzed by inspection of the density of states and electron localization function. Valence bands, band gap and final states of adsorbed CO2 were investigated and the effect of atomic displacements analyzed. The partial density of states (PDOS) of chemical adsorption of CO2 on the ZnO(0001) surface show that the p orbitals of CO2 were mixed with the ZnO valence band state appearing at the top of the valence band and in regions of low-energy conduction band.

Electron-Lattice Coupling in Armchair Graphene Nanoribbons.

We report the effects of electron-lattice coupling on the charge density distribution study of armchair graphene nanoribbons (GNRs). Here, we perform a theoretical investigation explaining the unexpected electronic density states observed experimentally. By means of a tight-binding approach with electron-lattice coupling, we obtained the same characteristic pattern of charge density along the C-C bonds suggested by both scanning tunneling and transmission electron microscopic measurements. Our results suggest electronic localized states whose sizes are dependent on the GNR width. We also show that our model rescues the quasi-particle charge-transport mechanism in GNRs. The remarkable agreement with experimental evidence allows us to conclude that our model could be, in many aspects, a fundamental tool when it comes to the phenomenological understanding of the charge behavior in this kind of system.

Sonographic examination of epiaortic vessels in patients with peripheral vertigo.

INTRODUCTION: To evaluate the utility of echo-color-Doppler ultrasonography (CDU) of extracranial brain-supplying vessels in patients with peripheral vertigo of unknown origin. MATERIALS AND METHODS: One-hundred-fifty-six patients (study group; 42 male and 114 female; mean age 61.86 ± 14.14) and 161 patients (control group; 80 male and 81 female; mean age 62.31 ± 13.69) were prospectively evaluated with CDU of extracranial brain-supplying vessels. Plaques in common and/or internal carotid artery (CA), arterial wall intima-media thickness (IMT) of common CA and peak systolic velocity (PSV) and resistive index (RI) of vertebral arteries (VA) were evaluated. Parametric (t-test) and non-parametric (Mann-Whitney U-test and Kolmogorov-Smirnov test) tests were applied. Logistic regression analysis was performed to provide odds ratio indicating the magnitude of risk of vertigo. Independent variables consisting of characteristics (age, sex), vascular risk factors (hypercholesterolemia, diabetes, hypertension) and CDU variables (IMT, plaque, PSV and RI of VA) were considered. RESULTS: Plaques were found in 31 (19.8%) patients of study group and in 43 (26.7%) patients of control group. IMT > 1 mm was found in 98 (62.8%) patients of study group and in 125 (77.6%) patients of control group.Statistical tests, applied to PSV and RI, showed no significant difference (p-value >0.05). At logistic regression analysis, vertigo was associated with age, sex, hypercholesterolemia, diabetes, hypertension and IMT (p < .01) while plaque, PSV and RI of VA were not significant factors (p > .05). DISCUSSION: IMT is the only CDU variable significantly associated with vertigo, especially in the lower age-classes (35-45 and 45-55) of study group.

New potential AChE inhibitor candidates.

We have theoretically studied new potential candidates of acetylcholinesterase (AChE) inhibitors designed from cardanol, a non-isoprenoid phenolic lipid of cashew Anacardium occidentale nut-shell liquid. The electronic structure calculations of fifteen molecule derivatives from cardanol were performed using B3LYP level with 6-31G, 6-31G(d), and 6-311+G(2d,p) basis functions. For this study we used the following groups: methyl, acetyl, N,N-dimethylcarbamoyl, N,N-dimethylamine, N,N-diethylamine, piperidine, pyrrolidine, and N,N-methylbenzylamine. Among the proposed compounds we identified that the structures with substitution by N,N-dimethycarbamoyl, N,N-dimethylamine, and pyrrolidine groups were better correlated to rivastigmine, and represent possible AChE inhibitors against Alzheimer disease.

Effects of hospital policies and practices on initiation and duration of breastfeeding.

BACKGROUND: The aim of this study was to verify if hospital policies and practices, independently of main maternal sociodemographic determinants, influence initiation and duration of breastfeeding. METHODS: The study was carried out at the Immunization Centre of Messina where all infants born in the four maternity wards of Messina are vaccinated, using a structured questionnaire, constructed in conformity with the methodology suggested by the WHO. RESULTS: Data analysis, performed by non-parametric and multivariate analysis of variance and by Kaplan-Meier curves, showed that the highest probability rate (P < 0.001) of initiation and duration of breastfeeding, independently of maternal age, parity, education levels, smoke and work was found in infants born in a University Hospital, characterized by earlier times of first suckling, longer hospital stay and higher rate of exclusive breastfeeding at discharge. CONCLUSION: Our data emphasize the role and responsibility of hospital policies and practices in the promotion, and in the duration of breastfeeding.

On the semiclassical initial value calculation of thermal rate coefficients for the N+N2 reaction.

In this paper we compare semiclassical initial value representation, conventional transition state theory with Wigner and Eckart tunneling correction, quantum reduced dimensionality, and quasiclassical thermal rate coefficients for N+N(2) exchange reaction.

Chronic sialoadenitis caused by Enterobius vermicularis: case report.

Enterobius vermicularis infection, an oro-faecal transmitted parasitosis, is a frequent finding in infant communities. Enterobius vermicularis is located predominantly in the caecum, appendix, and proximal areas of the ileum and colon, even if reports of some rare extra-intestinal cases have appeared in the literature. The case is reported here of a 62-year-old male presenting a mass in the right submandibular triangle. Histological examination, following removal of submandibular gland, revealed a granulomatous sialoadenitis due to Enterobius vermicularis. A review of the international literature confirms that this is a very rare site and it would appear to be the first report concerning enterobiasis in the salivary glands. Authors advance a hypothesis concerning a possible pathogenic mechanism.