Structural, electronic, and chemical properties of multiply iodized aluminum clusters

The electronic structure, stability, and reactivity of iodized aluminum clusters, which have been investigated via reactivity studies, are examined by first-principles gradient corrected density functional calculations. The observed behavior of Al13I−x and Al14I−x clusters is shown to indicate that for x⩽8, they consist of compact Al−13 and Al++14 cores, respectively, demonstrating that they behave as halogen- or alkaline earthlike superatoms. For x\u3e8, the Al cores assume a cagelike structure associated with the charging of the cores. The observed mass spectra of the reacted clusters reveal that Al13I−x species are more stable for even x while Al14I−x exhibit enhanced stability for odd x(x⩾3). It is shown that these observations are linked to the formation and filling of “active sites,” demonstrating a novel chemistry of superatoms

Full-rotation singularity-safe workspace for kinematically redundant parallel robots

This paper introduces and computes a novel type of work-space for kinematically redundant parallel robots that defines the regionin which the end-effector can make full rotations without coming close tosingular configurations; it departs from the traditional full-rotation dex-terous workspace, which considers full rotations without encounteringsingularities but does not take into account the performance problemsresulting from closeness to these locations. Kinematically redundant ar-chitectures have the advantage of being able to be reconfigured withoutchanging the pose of the end-effector, thus being capable of avoidingsingularities and being suitable for applications where high dexterityis required. Knowing the workspace of these robots in which the end-effector is able to complete full, smooth rotations is a key design aspectto improve performance; however, since this singularity-safe workspaceis generally small, or even non-existent, in most parallel manipulators,its characterisation and calculation have not received attention in theliterature. The proposed workspace for kinematically redundant robotsis introduced using a planar parallel architecture as a case study; the for-mulation works by treating the manipulator as two halves, calculatingthe full-rotation workspace of the end-effector for each half whilst ensur-ing singularity conditions are not approached or met, and then findingthe intersection of both regions. The method is demonstrated ontwoexample robot instances, and a numerical analysis is also carried out asa comparison

First-principles study of TMNan (TM= Cr, Mn, Fe, Co, Ni; n = 4-7) clusters

Geometry, electronic structure, and magnetic properties of TMNan (TM=Cr-Ni; n = 4-7) clusters are studied within a gradient corrected density functional theory (DFT) framework. Two complementary approaches, the first adapted to all-electron calculations on free clusters, and the second been on plane wave projector augmented wave (PAW) method within a supercell approach are used. Except for NiNan, the clusters in this series are found to retain the atomic moments of the TM atoms, and the magnetic moment presented an odd-even oscillation with respect to the number of Na atoms. The origin of these odd-even oscillations is explained from the nature of chemical bonding in these clusters. Differences and similarities between the chemical bonding and the magnetic properties of these clusters and the TMNan (TM = Sc, V and Ti; n = 4-6) clusters on one hand, and TM-doped Au and Ag clusters on the other hand, are discussed

Nitric oxide releasing-dendrimers: an overview

Platforms able to storage, release or scavenge NO in a controlled and specific manner is interesting for biological applications. Among the possible matrices for these purposes, dendrimers are excellent candidates for that. These molecules have been used as drug delivery systems and exhibit interesting properties, like the possibility to perform chemical modifications on dendrimers surface, the capacity of storage high concentrations of compounds of interest in the same molecule and the ability to improve the solubility and the biocompatibility of the compounds bonded to it. This review emphasizes the recent progress in the development and in the biological applications of different NO-releasing dendrimers and the nitric oxide release pathways in these compounds

Clostridium difficile infection.

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota

Distribución viral en plantas de cebolla ("Allium cepa" L.) asintomáticas

Using the DAS-ELISA method, the distribution of Onion yellow dwarf virus (OYDV), Garlic common latent virus (GarCLV), Shallot latent virus (SLV), Leek yellow stripe virus (LYSV), Tobacco etch virus (TEV) and tomato spotted wilt virus (TSWV) in the leaves, psdeudo-stem and the inflorescence of symptomless onion plants collected at different times in 2010, was studied in three locations in the State of Zacatecas, Mexico. We recorded the presence of these viruses in the organs just mentioned, although it was frequently detected mixed infections in single leaves where the most common interactions involved two, three or four viruses. There was no trend relating the viral presence with the analyzed vegetal organs or the leaf age; however, infections with only one virus appear to be less common in middle-aged leaves.Se estudió por medio de DAS- ELISA la distribución del Onion yellow dwarf virus (OYDV, virus del enanismo amarillo de la cebolla), Garlic common latent virus (GarCLV, virus latente común del ajo), Shallot latent virus (SLV, virus latente del chalote), Leek yellow stripe virus (LYSV: virus de la franja amarilla del puerro), Tobacco etch virus (TEV, virus del jaspeado del tabaco) y Tomato spotted wilt virus (TSWV, virus de la marchitez manchada del jitomate) en hojas, psdeudotallo e inflorescencia de plantas de cebolla asintomáticas colectadas en diferentes épocas de 2010 en tres localidades del estado de Zacatecas, México. Se registró la presencia de esos virus en los órganos mencionados aunque resultó frecuente detectar infecciones mezcladas en hojas individuales donde las interacciones más comunes involucraban dos, tres y cuatro virus. No se encontró una tendencia que relacione la presencia viral con los órganos vegetales analizados o con la edad de las hojas; sin embargo, las infecciones con un solo virus parecen ser menos frecuentes en las hojas de edad intermedia

Hortalizas y virosis en Zacatecas: un patosistema complejo

The chili pepper for drying, garlic and onion are economically important crops for the State of Zacatecas, Mexico. However, viral epidemics have emerged since the 1990s; the Experimental Field Zacatecas dependent of the INIFAP has conducted fragmented researches on these diseases, for this reason, the objective of this paper was to review and share information regarding the interaction between these crops with some viral pathogens, vectors and weed as well as striving the areas with the lack of knowledge which may require new or additional information. We have placed special emphasis on the identification of viruses and their vectors as a first step towards the establishment of an integrated management strategy: in a few years the presence of Curtovirus, Tospovirus, Carlavirus and Potyvirus, among others, have been reported infecting these crops in Zacatecas, MexicoEl cultivo de chile para secado, ajo y cebolla son económicamente importantes para el estado de Zacatecas, México. Sin embargo, epidemias virales han aparecido desde la década de 1990; el Campo Experimental Zacatecas, dependiente del INIFAP ha llevado a cabo investigación fragmentada sobre estas enfermedades, por lo que el objetivo del presente ensayo fue el de revisar y compartir la información sobre la interacción entre los cultivos de chile para secado, ajo y cebolla con algunos patógenos virales, vectores y maleza así como apuntar las áreas con falta de conocimiento donde se requiere nueva o mayor información. Se dado especial importancia a la identificación de virus y sus vectores como un primer paso para el establecimiento de una estrategia de manejo integrado: en pocos años la presencia de Curtovirus, Tospovirus, Carlavirus y Potyvirus, entre otros, ha sido reportada infectando esos cultivos en Zacatecas, Méxic

Comparative Effectiveness Randomized Clinical Trial Using Next-generation Microbial Sequencing to Direct Prophylactic Antibiotic Choice Before Urologic Stone Lithotripsy Using an Interprofessional Model

Background: Next-generation sequencing (NGS) methods for microbial profiling have increased sensitivity to detect urinary pathogens. Objective: To determine whether NGS microbial profiling can be used to guide antibiotic prophylaxis and reduce infection compared with the standard of care. Design, setting, and participants: A prospective randomized controlled clinical trial of patients undergoing urologic stone interventions at an academic health center from December 2019 to January 2022 was conducted. Urine was collected at the preoperative visit for standard culture and intervention NGS diagnostics. Evaluable patients were culture negative, met 2-wk follow-up, and did not cancel surgery. Of 240 individuals (control = 121, intervention = 119), 83 control and 74 intervention patients were evaluable. Intervention: Microbial findings (paired quantitative polymerase chain reaction and NGS) were sent to an infectious disease pharmacist to recommend prophylactic antimicrobial regimen. Outcome measurements and statistical analysis: The primary outcome was postoperative urinary infection within the follow-up period (Fisher’s exact test). The primary outcome was analyzed by modified intent-to-treat (mITT) and per-protocol analyses. Secondary endpoints considered included positive culture concordance, antibiotic use, and adverse events. Additional post hoc analyses investigated factors contributing to infection (univariate logistic regression). Results and limitations: The intervention significantly reduced postsurgical urinary infection risk by 7.1% (–0.73%, 15%) compared with the standard of care in the mITT analysis (1.4% vs 8.4%, p = 0.045) or by 8.5% (0.88%, 16%) compared with the per-protocol analysis (0% vs 8.5%, p = 0.032). NGS-guided treatment altered the distribution of antibiotics used (p = 0.025), and antibiotics poorly matched with NGS findings were associated with increased infection odds (odds ratio [OR] = 5.9, p = 0.046). Women were at greater odds to develop infection (OR = 10, p = 0.03) and possessed differentiated microbial profiles (p < 0.001). Conclusions: Urinary microbial NGS-guided antibiotic prophylaxis before endoscopic urologic stone lithotripsy improves antibiotic selection to reduce healthcare-associated urinary infections; however, treatment efficacy may be limited by the ability to adhere to the recommended protocol. Patient summary: We investigated whether microbial DNA sequencing could improve the selection of antibiotics before kidney stone surgery in patients not known to have any bacteria in the urine on standard culture. We found that using microbe DNA to guide antibiotic choices decreased postoperative infection rate and may encourage individualized use of available antibiotics