552 research outputs found
Investigation of nasal colonization of health care workers by methicillin-resistant Staphylococcus aureus with using new generation real-time PCR assay: Discussing of risks
Methicillin-resistant Staphylococcus aureus (MRSA) is a nasal infectious pathogen which is becoming of significant importance year by year. Mortality, morbidity and treatment costs of MRSA infectionshave all increased. The most effective preventative tool is rapid confirmation of MRSA existence, followed by efficient execution of the required infection control measures. This study was performedwith the aim of evaluating MRSA colonization in health care staff from intensive care units (internal and surgical intensive care units) (ICUs) and how certain risk factors affect their colonization status. The study was conducted prospectively using samples obtained from nasal swabs of health-care staffs working in different missions in the intensive care unit of Gaziantep University Training Hospital in southeast of Turkey. The nasal swab samples were processed using a real-time PCR method platformcalled GeneXpert (Cepheid). Our PCR screen revealed the presence of MRSA in 14 of 98 health-care staffs. Of these 14 health-care staffs carrying nasal MRSA, 10 were male, 8 were assistant health-care personnel and 11 have been working for over one year in the intensive care unit. Our data showed that male gender and an employment during of more than one year served as significant risk factors for nasal MRSA colonization
Erdheim Chester disease presented isolated breast and axillary involvement
Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis of unknown aetiology. The most common sites of involvement are the long bones, skin, orbit, pituitary and retroperitoneal space. Isolated breast involvement is rare in the literature. ECD of the breast has been rarely reported. ECD should be considered in the differential diagnosis of histiocytoid breast lesions, including fat necrosis and histiocytoid invasive mammary carcinoma. In this case report, we present an unusual presentation isolated breast involvement of ECD with radiological and histopathology findings
The zebrafish reveals dependence of the mast cell lineage on Notch signaling in vivo
We used the opportunities afforded by the zebrafish to determine upstream pathways regulating mast cell development in vivo and identify their cellular origin. Colocalization studies demonstrated zebrafish notch receptor expression in cells expressing carboxypeptidase A5 (cpa5), a zebrafish mast cell-specific marker. Inhibition of the Notch pathway resulted in decreased cpa5 expression in mindbomb mutants and wild-type embryos treated with the γ-secretase inhibitor, Compound E.Aseries of morpholino knockdown studies specifically identified notch1b and gata2 as the critical factors regulating mast cell fate. Moreover, hsp70::GAL4;UAS::nicd1a transgenic embryos overexpressing an activated form of notch1, nicd1a, displayed increased cpa5, gata2, and pu.1 expression. This increase in cpa5 expression could be reversed and reduced below baseline levels in a dose-dependent manner usingCompound E. Finally, evidence that cpa5 expression colocalizes with lmo2 in the absence of hematopoietic stem cells revealed that definitive mast cells initially delineate from erythromyeloid progenitors. These studies identify a master role for Notch signaling in vertebrate mast cell development and establish developmental origins of this lineage. Moreover, these findings postulate targeting the Notch pathway as a therapeutic strategy in mast cell diseases. © 2012 by The American Society of Hematology
Graphene-gold supercapacitor as a voltage controlled saturable absorber for femtosecond pulse generation
We report, for the first time to the best of our knowledge, use of a graphene-gold supercapacitor as a voltage controlled fast saturable absorber for femtosecond pulse generation. The unique design involving only one graphene electrode lowers the insertion loss of the device, in comparison with capacitor designs with two graphene electrodes. Furthermore, use of the high-dielectric electrolyte allows reversible, adjustable control of the absorption level up to the visible region with low bias voltages of only a few volts (0-2 V). The fast saturable absorber action of the graphene-gold supercapacitor was demonstrated inside a multipass-cavity Cr:forsterite laser to generate nearly transform-limited, sub-100 fs pulses at a pulse repetition rate of 4.51 MHz at 1.24 μm. © 2016 Optical Society of America
Graphene-gold supercapacitor as a voltage-controlled saturable absorber for femtosecond pulse generation
We report, for the first time to our knowledge, a voltage-controlled graphene-gold supercapacitor saturable absorber, as a modulator with adjustable insertion loss for low-gain mode-locked lasers. Nearly transform-limited, 80-fs pulses were generated near 1240 nm. © OSA 2015
High-responsivity graphene photodetectors integrated on silicon microring resonators.
Graphene integrated photonics provides several advantages over conventional Si photonics. Single layer graphene (SLG) enables fast, broadband, and energy-efficient electro-optic modulators, optical switches and photodetectors (GPDs), and is compatible with any optical waveguide. The last major barrier to SLG-based optical receivers lies in the current GPDs' low responsivity when compared to conventional PDs. Here we overcome this by integrating a photo-thermoelectric GPD with a Si microring resonator. Under critical coupling, we achieve >90% light absorption in a ~6 μm SLG channel along a Si waveguide. Cavity-enhanced light-matter interactions cause carriers in SLG to reach ~400 K for an input power ~0.6 mW, resulting in a voltage responsivity ~90 V/W, with a receiver sensitivity enabling our GPDs to operate at a 10-9 bit-error rate, on par with mature semiconductor technology, but with a natural generation of a voltage, rather than a current, thus removing the need for transimpedance amplification, with a reduction of energy-per-bit, cost, and foot-print
Graphene-perovskite fibre photodetectors
The integration of optoelectronic devices, such as transistors and
photodetectors (PDs), into wearables and textiles is of great interest for
applications such as healthcare and physiological monitoring. These require
flexible/wearable systems adaptable to body motions, thus materials conformable
to non-planar surfaces, and able to maintain performance under mechanical
distortions. Here, we prepare fibre PDs combining rolled graphene layers and
photoactive perovskites. Conductive fibres (500/cm) are made by
rolling single layer graphene (SLG) around silica fibres, followed by
deposition of a dielectric layer (AlO and parylene C), another
rolled SLG as channel, and perovskite as photoactive component. The resulting
gate-tunable PDs have response time5ms, with an external
responsivity22kA/W at 488nm for 1V bias. The external responsivity is two
orders of magnitude higher and the response time one order of magnitude faster
than state-of-the-art wearable fibre based PDs. Under bending at 4mm radius, up
to80\% photocurrent is maintained. Washability tests show72\% of
initial photocurrent after 30 cycles, promising for wearable applications
Evaluation of Two Different Hand Hygiene Procedures during Routine Patient Care
In this study, the antimicrobial efficacy of hand washing (HW) and hand washing plus rubbing with an alcohol-based solution (HWR) on numbers of total and transient flora colonies on the hands of healthcare workers (HCWs) during routine patient care was assessed. Samples were collected, using a standard bag broth technique, from the hands of 154 HCWs, before and immediately after carrying out a hand hygiene procedure. The numbers of total and transient flora colonies per plate were counted and transient pathogens were identified. A significant statistical difference between ward speciality was detected with respect to the isolation rate of transient flora. Transient hand flora were recovered from 25.3% of HCWs before carrying out the hand hygiene procedure. With respect to the disappearance and prevention of regrowth of transient flora after hand hygiene, the HWR technique was significantly more effective than HW. In conclusion, a disinfectant should be added to the hand washing process to achieve optimum protection against nosocomial infections in routine hospital practice
A transgenic zebrafish model expressing KIT-D816V recapitulates features of aggressive systemic mastocytosis
Summary: Systemic mastocytosis (SM) is a rare myeloproliferative disease without curative therapy. Despite clinical variability, the majority of patients harbour a KIT-D816V mutation, but efforts to inhibit mutant KIT with tyrosine kinase inhibitors have been unsatisfactory, indicating a need for new preclinical approaches to identify alternative targets and novel therapies in this disease. Murine models to date have been limited and do not fully recapitulate the most aggressive forms of SM. We describe the generation of a transgenic zebrafish model expressing the human KIT-D816V mutation. Adult fish demonstrate a myeloproliferative disease phenotype, including features of aggressive SM in haematopoeitic tissues and high expression levels of endopeptidases, consistent with SM patients. Transgenic embryos demonstrate a cell-cycle phenotype with corresponding expression changes in genes associated with DNA maintenance and repair, such as reduced dnmt1. In addition, epcam was consistently downregulated in both transgenic adults and embryos. Decreased embryonic epcam expression was associated with reduced neuromast numbers, providing a robust in vivo phenotypic readout for chemical screening in KIT-D816V-induced disease. This study represents the first zebrafish model of a mast cell disease with an aggressive adult phenotype and embryonic markers that could be exploited to screen for novel agents in SM
Femtosecond pulse generation from an extended cavity Cr4+: Forsterite laser using graphene on YAG
A room temperature, multipass-cavity, femtosecond Cr4+:forsterite laser was modelocked with a single-layer graphene saturable absorber on a YAG substrate. The resonator produced nearly transform-limited 92 fs pulses near 1250 nm with 53 kW of peak power. © OSA 2013
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