1,690 research outputs found
Magneto-optical characterization of MnxGe1-x alloys obtained by ion implantation
Magneto-optical Kerr effect hysteresis loops at various wavelengths in the
visible/near-infrared range have been used to characterize the magnetic
properties of alloys obtained by implanting Mn ions at fixed energy in a Ge
matrix. The details of the hysteresis loops reveal the presence of multiple
magnetic contributions. They may be attributed to the inhomogeneous
distribution of the magnetic atoms and, in particular, to the known coexistence
of diluted Mn in the Ge matrix and metallic Mn-rich nanoparticles embedded in
it [Phys. Rev. B 73, 195207(2006)].Comment: 2 pages, 2 figures. Proceeding of the International Conference on
Magnetism. Kyoto, August 20-25 200
A genetic algorithm-assisted semi-adaptive MMSE multi-user detection for MC-CDMA mobile communication systems
In this work, a novel Minimum-Mean Squared-Error (MMSE) multi-user detector is proposed for MC-CDMA transmission systems working over mobile radio channels characterized by time-varying multipath fading. The proposed MUD algorithm is based on a Genetic Algorithm (GA)-assisted per-carrier MMSE criterion. The GA block works in two successive steps: a training-aided step aimed at computing the optimal receiver weights using a very short training sequence, and a decision-directed step aimed at dynamically updating the weights vector during a channel coherence period. Numerical results evidenced BER performances almost coincident with ones yielded by ideal MMSE-MUD based on the perfect knowledge of channel impulse response. The proposed GA-assisted MMSE-MUD clearly outperforms state-of-the-art adaptive MMSE receivers based on deterministic gradient algorithms, especially for high number of transmitting users
Animal models for oral transmission of Listeria monocytogenes
Listeria monocytogenes has been recognized as a food borne pathogen in humans since the 1980s, but we still understand very little about oral transmission of L. monocytogenes or the host factors that determine susceptibility to gastrointestinal infection, due to the lack of an appropriate small animal model of oral listeriosis. Early feeding trials suggested that many animals were highly resistant to oral infection, and the more reproducible intravenous or intraperitoneal routes of inoculation soon came to be favored. There are a fair number of previously published studies using an oral infection route, but the work varies widely in terms of bacterial strain choice, the methods used for oral transmission, and various manipulations used to enhance infectivity. This mini review summarizes the published literature using oral routes of L. monocytogenes infection and highlights recent technological advances that make oral infection a more attractive model system
Extracellular glutathione decreases the ability of Burkholderia cenocepacia to penetrate into epithelial cells and to induce an inflammatory response
The airway surface liquid (ASL) of Cystic Fibrosis (CF) patients contains a lower concentration of reduced glutathione (GSH) with respect to healthy people. It is not known whether this defect may favor lung colonization by opportunistic pathogens
An ERp57-mediated disulphide exchange promotes the interaction between Burkholderia cenocepacia and epithelial respiratory cells
Previous studies have demonstrated that extracellular glutathione reduces the ability of the Cystic Fibrosis pathogen Burkholderia cenocepacia to infect primary or immortalized epithelial respiratory cells. We report here that the adhesion and invasion ability of B. cenocepacia is limited also by thiol-oxidizing and disulphide-reducing agents and by protein disulfide isomerase (PDI) inhibitors. PDI inhibitors also reduce the proinflammatory response elicited by cells in response to Burkholderia. These findings indicate that a membrane-associated PDI catalyzes thiol/disulphide exchange reactions which favor bacterial infection. The combined use of selective PDI inhibitors, RNA silencing and specific antibodies identified ERp57 as a major PDI involved in the interaction between B. cenocepacia and epithelial cells. This study contributes to the elucidation of the Burkholderia pathogenic mechanisms by showing that this microorganism exploits a membrane-associated host protein to infect epithelial cells and identifies ERp57 as a putative pharmacological target for the treatment of Burkholderia lung infections
Dexamethasone in acute cardiopulmonary syndrome with hyperinflammatory state
Abstract
Introduction
Elderly patient hospitalized due to acute heart failure often have a concomitant acute lung disease (acute bronchitis, pneumonia, chronic obstructive pulmonary disease-COPD- exacerbation). Establishing the role of each disease in a clinical picture of acute cardiopulmonary syndrome can be challenging. Procalcitonin has been used as a guide to antibiotic therapy with contrasting results. A common thread of these diseases is inflammation; a hyperinflammatory response determines more serious symptoms and a worse prognosis.
Purpose
We evaluated the effectiveness of a treatment with dexamethasone in patients with acute cardiopulmonary syndrome and a strong inflammatory response.
Materials and methods
We evaluated 157 consecutive HFPEF (heart failure with preserved ejection fraction) patients ≥80 years of age, with concomitant symptoms attributable to acute bronchitis, pneumonia, or COPD exacerbation, hospitalized due to worsening dyspnoea, with an NT-proBNP ≥3,000 pg/ml, and a finding X-ray of lung congestion with or without a consolidation. Reactive C Protein was measured. Patients with SARS-CoV-2, indication to corticosteroids use for other clinical conditions or need for mechanical ventilation were excluded. The 96 patients with values>20 mg/dl were randomized into 2 groups: 48 patients were treated open-label with dexamethasone at a dose of 8 mg iv/day for a maximun of ten days, in addition to the usual therapies for acute heart failure and lung disease, while the same number of patients were treated with the usual therapy. In both groups the antibiotic was administered only if the procalcitonin was≥0.25 μg/L. Clinical recovery time, length of hospitalization, in-hospital mortality, the need for a new hospitalization and mortality at one month were evaluated.
Results
The mean age of the patients was 88±4 years in the dexamethasone group and 87±5 in the usual therapy group. The results are shown in Table 1. Patients treated with dexamethasone experienced a faster clinical recovery and a shorter length of hospitalization. No significant differences were found regarding either in-hospital mortality or need for rehospitalization and mortality at 30 days.
Conclusions
Very elderly patients with acute cardiopulmonary syndrome and hyperinflammatory state associated with an excessive increase in Reactive Protein C have a favorable response to dexamethasone therapy in addition to the usual therapy in terms of clinical improvement and length of hospitalization. Our case history is small to evaluate a possible improvement in mortality. These findings need to be consolidated from double-blind randomized controlled trials
Funding Acknowledgement
Type of funding sources: None. Table
Assessment of Natural Resources Use for Sustainable Development - DPSIR Framework for Case Studies in Portsmouth and Thames Gateway, U.K.
This chapter reports on the uses of the DPSIR framework to assess the sustainability of the intertidal environments within the two UK case study areas, Portsmouth and Thames Gateway. It focuses on statutory conservation areas dominated by intertidal habitats. Two are located in Portsmouth (Portsmouth and Langstone Harbours) and four in the Thames Gateway (Benfleet Marshes, South Thames Estuary, Medway Estuary and the Swale in the Thames Gateway). Based on the reduction of a number of pressures and impacts observed in recent decades and the improvement of overall environmental quality, all six SSSIs are considered to be sustainable in the short and medium term. In the future, it is possible that the impacts of climate change, especially sea-level rise, might result in further reduction in the area and/or quality of intertidal habitats. Further integration between conservation and planning objectives (both for urban development and management of flood risk) at local level is needed to support the long-term sustainability of intertidal habitats
Botulinum toxin associated with fissurectomy and anoplasty for hypertonic chronic anal fissure: A case-control study
BACKGROUND Lateral internal sphincterotomy is still the approach of choice for the treatment of chronic anal fissure (CAF) with internal anal sphincter (IAS) hypertonia, but it is burdened by high-risk postoperative faecal incontinence (FI). Sphincter saving procedures have recently been reconsidered as treatments to overcome this risk. The most employed procedure is fissurectomy with anoplasty, eventually associated with pharmacological sphincterotomy. AIM To evaluate whether fissurectomy and anoplasty with botulinum toxin injection improves the results of fissurectomy and anoplasty alone. METHODS We conducted a case-control study involving 30 male patients affected by CAF with hypertonic IAS who underwent fissurectomy and anoplasty with V-Y cutaneous flap advancement. The patients were divided into two groups: Those in group I underwent surgery alone, and those in group II underwent surgery and a botulinum toxin injection directly into the IAS. They were followed up for at least 2 years. The goals were to achieve complete healing of the patient and to assess the FI and recurrence rate along with manometry parameters. RESULTS The intensity and duration of post-defecatory pain decreased significantly in both groups of patients starting with the first defecation, and this reduction was higher in group II. Forty days after surgery, we achieved complete wound healing in all the patients in group II but only in 80% of the patients in group I (P < 0.032). We recorded 2 cases of recurrence, one in each group, and both healed with conservative therapy. We recorded one temporary and low-grade postoperative case of “de novo” FI. Manometry parameters reverted to the normal range earlier for group II patients. CONCLUSION The injection of botulinum toxin A in association with fissurectomy and anoplasty with a V-Y advancement flap improves the results of surgery alone in patients affected by CAF with IAS hypertonia
A Serendipitous Mutation Reveals the Severe Virulence Defect of a Klebsiella pneumoniae fepB Mutant
ABSTRACT Klebsiella pneumoniae is considered a significant public health threat because of the emergence of multidrug-resistant strains and the challenge associated with treating life-threatening infections. Capsule, siderophores, and adhesins have been implicated as virulence determinants of K. pneumoniae , yet we lack a clear understanding of how this pathogen causes disease. In a previous screen for virulence genes, we identified a potential new virulence locus and constructed a mutant ( smr ) with this locus deleted. In this study, we characterize the smr mutant and show that this mutation renders K. pneumoniae avirulent in a pneumonia model of infection. The smr mutant was expected to have a deletion of three genes, but subsequent genome sequencing indicated that a much larger deletion had occurred. Further analysis of the deleted region indicated that the virulence defect of the smr mutant could be attributed to the loss of FepB, a periplasmic protein required for import of the siderophore enterobactin. Interestingly, a Δ fepB mutant was more attenuated than a mutant unable to synthesize enterobactin, suggesting that additional processes are affected. As FepB is highly conserved among the members of the family Enterobacteriaceae , therapeutic targeting of FepB may be useful for the treatment of Klebsiella and other bacterial infections. IMPORTANCE In addition to having a reputation as the causative agent of several types of hospital-acquired infections, Klebsiella pneumoniae has gained widespread attention as a pathogen with a propensity for acquiring antibiotic resistance. It is capable of causing a range of infections, including urinary tract infections, pneumonia, and sepsis. Because of the rapid emergence of carbapenem resistance among Klebsiella strains, there is a dire need for a better understanding of virulence mechanisms and identification of new drug targets. Here, we identify the periplasmic transporter FepB as one such potential target
Plasmonics on a Neural Implant: Engineering Light–Matter Interactions on the Nonplanar Surface of Tapered Optical Fibers
Optical methods are driving a revolution in neuroscience. Ignited by optogenetic techniques, a set of strategies has emerged to control and monitor neural activity in deep brain regions using implantable photonic probes. A yet unexplored technological leap is exploiting nanoscale light-matter interactions for enhanced bio-sensing, beam-manipulation and opto-thermal heat delivery in the brain. To bridge this gap, we got inspired by the brain cells’ scale to propose a nano-patterned tapered-fiber neural implant featuring highly-curved plasmonic structures (30 μm radius of curvature, sub-50 nm gaps). We describe the nanofabrication process of the probes and characterize their optical properties. We suggest a theoretical framework using the interaction between the guided modes and plasmonic structures to engineer the electric field enhancement at arbitrary depths along the implant, in the visible/near-infrared range. We show that our probes can control the spectral and angular patterns of optical transmission, enhancing the angular emission and collection range beyond the reach of existing optical neural interfaces. Finally, we evaluate the application as fluorescence and Raman probes, with wave-vector selectivity, for multimodal neural applications. We believe our work represents a first step towards a new class of versatile nano-optical neural implants for brain research in health and disease.M.D.V., M.G., and Fe.P. jointly supervised and are co-last authors in this work. Fi.P., A.B., and Fe.P. acknowledge funding from the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 677683. F.D.A., L.M.d.l.P., M.V., M.D.V., and Fe.P. acknowledge funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 828972. Fi.P., M.D.V., and Fe.P. acknowledge that this project has received funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No. 101016787. M.P., Fe.P., and M.D.V. were funded by the U.S. National Institutes of Health (Grant No. 1UF1NS108177-01). Open access funding provided by Istituto Italiano di Tecnologia within the CRUI-CARE agreemen
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