551 research outputs found
Dimensional analysis and Rutherford Scattering
Dimensional analysis, and in particular the Buckingham theorem is
widely used in fluid mechanics. In this article we obtain an expression for the
impact parameter from Buckingham's theorem and we compare our result with
Rutherford's original discovery found in the early twentieth century
Macroscopic CNT fibres inducing non-epitaxial nucleation and orientation of semicrystalline polymers
In the presence of macroscopic fibres of carbon nanotubes (CNT), various semicrystalline polymers
are shown to present accelerated crystallisation through the formation of a transcrystalline (TC) layer
perpendicular to the fibre axis. From differential scanning calorimetry, polarized optical microscopy
and X-ray diffraction we establish this to be due to much faster nucleation rates at the fibre surface.
The formation of a TC layers is demonstrated for polyvinyldene fluoride, isotactic polypropylene and
poly(lactic acid) in spite of the large differences in their chemistry and structure unit cells, suggesting
that epitaxy in terms of lattice type or size matching is not a prerequisite. For the three polymers as
well as poly(ether ether ketone), the TC layer is identically oriented with the chain axis in the lamella
parallel to the CNTs, as observed by wide and small angle X-ray scattering. These results point to
polymer chain orientation at the point of adsorption and the formation of a mesomorphic layer as
possible steps in the fast nucleation of oriented lamella, with wetting of the CNT fibre surface by the
molten semi-crystalline polymer a key condition for heterogeneous nucleation to take place
Measurement of urea and creatinine in saliva of dogs : a pilot study
Urea and creatinine in saliva have been reported to be possible markers of chronic kidney disease (CKD) in humans. The aim of this study was to assess if urea and creatinine could be measured in canine saliva, and to evaluate their possible changes in situations of CKD
Analyses of chondrogenic induction of adipose mesenchymal stem cells by combined co-stimulation mediated by adenoviral gene transfer
INTRODUCTION: Adipose-derived stem cells (ASCs) have the potential to differentiate into cartilage under stimulation with some reported growth and transcriptional factors, which may constitute an alternative for cartilage replacement approaches. In this study, we analyzed the in vitro chondrogenesis of ASCs transduced with adenoviral vectors encoding insulin-like growth factor-1 (IGF-1), transforming growth factor beta-1 (TGF-β1), fibroblast growth factor-2 (FGF-2), and sex-determining region Y-box 9 (SOX9) either alone or in combinations. METHODS: Aggregate cultures of characterized ovine ASCs were transduced with 100 multiplicity of infections of Ad.IGF-1, Ad.TGF-β1, Ad.FGF-2, and Ad.SOX9 alone or in combination. These were harvested at various time points for detection of cartilage-specific genes expression by quantitative real-time PCR or after 14 and 28 days for histologic and biochemical analyses detecting proteoglycans, collagens (II, I and X), and total sulfated glycosaminoglycan and collagen content, respectively. RESULTS: Expression analyses showed that co-expression of IGF-1 and FGF-2 resulted in higher significant expression levels of aggrecan, biglycan, cartilage matrix, proteoglycan, and collagen II (all P ≤0.001 at 28 days). Aggregates co-transduced with Ad.IGF-1/Ad.FGF-2 showed a selective expression of proteoglycans and collagen II, with limited expression of collagens I and × demonstrated by histological analyses, and had significantly greater glycosaminoglycan and collagen production than the positive control (P ≤0.001). Western blot analyses for this combination also demonstrated increased expression of collagen II, while expression of collagens I and × was undetectable and limited, respectively. CONCLUSION: Combined overexpression of IGF-1/FGF-2 within ASCs enhances their chondrogenic differentiation inducing the expression of chondrogenic markers, suggesting that this combination is more beneficial than the other factors tested for the development of cell-based therapies for cartilage repair
The importance of organizational variables in treatment time for patients with ST-elevation acute myocardial infarction improve delays in STEMI
Background: The time between arrival at the emergency department (ED) and balloon (D2B) in STEMI is one of the best indicators of the quality of care. Our aim is to describe treatment times and evaluate the causes of delay. Methods: This is an observational retrospective study, including all consecutive STEMI code patients ≥18 years old treated in the ED from 2013 to 2016.All the patients were stratified into two groups: delayed group with D2B > 70 min and non-delayed ≤70. The primary variable was D2B time. Findings: In total 327 patients were included, stratified according to their D2B as follows: 166 (67·48%) in the delayed group and 80 (32·52%) in the non-delayed group. The delayed group was older (p = 0·005), with more females (p = 0·060) and more atypical electrocardiogram (ECG) STEMI signs or symptoms (p = 0·058) (p = 0·087). Predictors of shorter D2B time were: typical STEMI ECG signs and short training sessions for nurses on identifying STEMI patients. Interpretation: There are delays particularly in specific groups with atypical clinical presentations. Short training sessions aimed at emergency nurses correlate with shorter delay. This suggests that continuing training for emergency nurses, along with organizational strategies, can contribute to increasing the quality of care. Clinical trial number: NCT0433338
Efficacy of DNA amplification in tissue biopsy samples to improve the detection of invasive fungal disease
AbstractThe performance of a pan-fungal PCR-based technique was evaluated to assess the aetiology of invasive fungal diseases (IFDs). A total of 89 formalin-fixed paraffin-embedded biopsy samples from 84 patients with proven IFD were studied. Culture of tissue was performed in 68 (81%) patients. The sensitivities of the PCR-based technique and microbiological culture of tissues were 89% and 56%, respectively (p <0.01). According to PCR results, Aspergillus species accounted for 67%, Candida species for 13%, zygomycetes for 11%, and rare and emerging fungi for 9%. Aspergillus species were significantly associated with lung samples (79.6%, p <0.01), Mucorales were associated with skin/subcutaneous samples, and Candida species were associated with gastrointestinal samples. Regarding biopsy samples with Aspergillus species, Aspergillus fumigatus DNA was detected in 43 of 50 (86%), and Aspergillus flavus in six of 50 (12%). PCR was positive in 24 of 30 (80%) cases with negative culture. In nine of the 84 patients, the PCR technique failed to amplify the DNA. Six also had negative cultures, and in the remaining three cases culture was positive (Rhizopus microsporus, Rhizopus arrhizus, and Sakseneae vasiformis), suggesting that the PCR technique was not as effective in amplifying the DNA of some species of Zygomycetes. In five cases, there was no correlation between culture results and those obtained with DNA amplification, indicating the possibility of a mixed infection or the presence of colonizer/contaminant microorganisms. In summary, PCR-based techniques for DNA amplification should be implemented in histopathology and microbiology departments, as they appear to be complementary to conventional methods for IFD detection
Monomial ideals whose depth function has any given number of strict local maxima
We construct monomial ideals with the property that their depth function has
any given number of strict local maxima
29-Si NMR and Hidden Order in URu2Si2
We present new 29-Si NMR spectra in URu2Si2 for varying temperature T, and
external field H. On lowering T, the systematics of the low-field lineshape and
width reveal an extra component (lambda) to the linewidth below T_N ~ 17 K not
observed previously. We find that lambda is magnetic-field independent and
dominates the low-field lineshape for all orientations of H with respect to the
tetragonal c axis. The behavior of lambda indicates a direct relationship
between the 29-Si spin and the transition at T_N, but it is inconsistent with a
coupling of the nuclei to static antiferromagnetic order/disorder of the U-spin
magnetization. This leads us to conjecture that lambda is due to a coupling of
29-Si to the system's hidden-order parameter. A possible coupling mechanism
involving charge degrees of freedom and indirect nuclear spin/spin interactions
is proposed. We also propose further experiments to test for the existence of
this coupling mechanism.Comment: 4 pages, 4 figures, submitted to PR
TREM1 regulates antifungal immune responses in invasive pulmonary aspergillosis.
Pattern recognition receptors (PRRs) are responsible for Aspergillus fumigatus recognition by innate immunity and its subsequent immune signaling. The triggering receptor expressed on myeloid cells 1 (TREM1) is a recently characterized pro-inflammatory receptor constitutively expressed on the surface of neutrophils and macrophages. A soluble form (sTREM1) of this protein that can be detected in human body fluids has been identified. Here we investigated the role of TREM1 during invasive pulmonary aspergillosis (IPA). IPA patients displayed significantly higher levels of sTREM1 in bronchoalveolar lavages when compared to control patients. Functional analysis in TREM1 showed that the levels of sTREM1 and TREM1 pathway-related cytokines were influenced by single nucleotide polymorphisms in TREM1. In addition, we confirmed a role of TREM1 on antifungal host defense against A. fumigatus in a murine model of IPA. TREM1 deficiency increased susceptibility to infection in the immunosuppressed murine host. Deletion of TREM1 showed delayed innate and adaptive immune responses and impaired pro-inflammatory cytokine responses. The absence of TREM1 in primary macrophages attenuated the TLR signaling by altering the expression of both receptor and effector proteins that are critical to the response against A. fumigatus. In this study, and for the first time, we demonstrate the key role for the TREM1 receptor pathway during IPA.This work was supported by the Fundação para a Ciência e a Tecnologia [PTDC/SAU-SER/29635/2017]; Fundação para a Ciência e a Tecnologia [UIDB/50026/2020 and UIDP/50026/2020]; Fundação para a Ciência e a Tecnologia [PTDC/MED-GEN/28778/2017]; H2020 Excellent Science [NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023)]; Instituto de Salud Carlos III [RD16/CIII/0004/0003]; Instituto de Salud Carlos III [PI18CIII/00045]; Instituto de Salud Carlos III [MPY 1277/15]; Ministerio de Ciencia, Innovación y Universidades [RTI2018-099114-B-I00]; Associação Viver a Ciência (PT) [SFRH/BD/136814/2018]; “la Caixa” Foundation [ID 100010434].S
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