92 research outputs found

    Analysis of the Rare BcDs,dl+lB_c \to D_{s,d}^{*} l^+ l^- Decays in QCD

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    The rare BcDs,dl+lB_c \to D_{s,d}^{*} l^+ l^- decays are investigated in the framework of the three point QCD sum rules approach. Considering the gluon condensate corrections to the correlation function, the form factors relevant to these transitions are calculated. The total decay width and branching ratio for these decays are also evaluated. The results for the branching ratios are in good agreement with the quark models.Comment: 20 Pages, 2 Figures and 5 Table

    Investigation of the Ds1D_{s1} structure via BcB_c to Ds1l+l/ννˉD_{s1} l^+l^-/\nu\bar\nu transitions in QCD

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    We investigate the structure of the Ds1(2460,2536)(JP=1+)D_{s1}(2460,2536) (J^P=1^+) mesons via analyzing the semileptonic BcDs1l+lB_{c}\to D_{s1}l^+l^-, l=τ,μ,el=\tau, \mu, e and BcDs1ννˉB_{c}\to D_{s1}\nu\bar{\nu} transitions in the framework of the three--point QCD sum rules. We consider the Ds1D_{s1} meson in two ways, the pure csˉ>|c\bar{s}> state and then as a mixture of two 3P1>|^3P_1> and 1P1>|^1P_1> states. Such type rare transitions take place at loop level by electroweak penguin and weak box diagrams in the standard model via the flavor changing neutral current transition of bsb \to s. The relevant form factors are calculated taking into account the gluon condensate contributions. These form factors are numerically obtained for csˉ>|c\bar s> case and plotted in terms of the unknown mixing angle θs\theta_s, when the Ds1D_{s1} meson are considered as mixture of two 3P1>|^3P_1> and 1P1>|^1P_1> states. The obtained results for the form factors are used to evaluate the decay rates and branching ratios. Any future experimental measurement on these form factors as well as decay rates and branching fractions and their comparison with the obtained results in the present work can give considerable information about the structure of this meson and the mixing angle θs\theta_s.Comment: 33 Pages, 11 Figures and 5 Table

    Aspergillosis of central nervous system in patients with leukemia and stem cell transplantation: a systematic review of case reports

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    Background: Aspergillosis of Central Nervous System (CNS) is a highly lethal infection in patients with leukemia and Stem Cell Transplantation (SCT). Methods: Case reports of CNS aspergillosis in patients with leukemia and SCT published between 1990 and August 2020 were gathered using a structured search through PubMed/Medline. Results: Sixty-seven cases were identified over the searches of the PubMed bibliographic database and then, 59 cases were included in the final analysis. Europe had the largest share of cases at 57.6 (34 reports), followed by Americas and Asia. Affected patients were predominantly males (58.6) and the mean age of the patients was 36.1 years, while 62.7 of the patients were under the age of 50 years. The most common leukemia types include Acute Lymphoblastic Leukemia (ALL), Chronic Lymphocytic Leukemia (CLL), and Acute Myeloid Leukemia (AML) at 43.4, 27.4, and 23.5, respectively. Furthermore, stem cell transplantation was reported in 11 cases. The overall mortality was 33; however, the attributable mortality rate of CNS aspergillosis was 24.5. Altered mental status, hemiparesis, cranial nerve palsies, and seizures were the clearest manifestations of infection and lung involvement reported in 57 of the patients. Histopathologic examination led to the diagnosis of infection in 57 of the patients followed by culture (23.7), galactomannan assay (8.5), and molecular method (3.3). Amphotericin B and voriconazole were the most frequently used drugs for infection treatment. Good results were not obtained in one-third of the patients treated by voriconazole. Finally, neurosurgical intervention was used for 23 patients (39). Conclusion: CNS aspergillosis is a rapidly progressive infection in leukemic patients. Thus, these patients should be followed up more carefully. Furthermore, management of induction chemotherapy, use of different diagnostic methods, and use of appropriate antifungal can lead to infection control. © 2021, The Author(s)

    The Effects of Fourth Generation on the double Lepton Polarization in B \rar K \ell^+ \ell^- decay

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    This study investigates the influence of the fourth generation quarks on the double lepton polarizations in B \rar K \ell^+ \ell^- decay. Taking |V_{t's}V_{t'b}|\sim \{0.01-0.03\} with phase about 100^\circ, which is consistent with the b\to s\ell^+\ell^- rate and the B_s mixing parameter Delta m_{B_s}$, we obtain that the double lepton(muon and tau) polarizations are quite sensitive to the existence of fourth generation. It can serve as a good tool to search for new physics effects, precisely, to indirect search for the fourth generation quarks(t', b').Comment: 30 pages, 27 figure

    Emergency Water Information Network (EWIN)

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    Flooding is a global problem and as a representative example, Mexico is currently struggling to manage flood situations which are increasing in regularity and severity. Many developing countries have substandard flood monitoring infrastructure. However, in common with the UK, they have state-of-the-art cellular mobile phone systems. In this research, expertise in water engineering and radio communications from the UK and Mexico have been combined to design a cost effective flood forecasting system based on hydrology sensing and mobile networks. Recent events such as hurricane Patricia in Mexico (October 2015) has emphasised the need for systems that can predict the dynamic behaviour of large-scale water flows. Currently, management of flood situations in many developing countries is carried out through prediction of water behaviour (Hydro Meteorological Warning System). This system is based on estimates of rainfall, runoff and water levels. In Mexico two central registers and rain measuring stations are used to gather data. The data collected is compared with pre-established risk thresholds which determine whether a warning should be issued. In general, the rainy season in Mexico occurs during the summer and fall, starting in May and ending in October. Along the main waterways, the change in state is dynamic between dry and rainy both in terms of the water volume in the channels and the vegetation on the banks. Vegetation in Mexico is normally sparse but grows quickly and in abundance during the rainy season. During flood events, new rivers form along river beds that are normally empty. These conditions are typical of flooding in many countries. In order to develop a real time flood forecasting system, several areas of research need to be investigated. These include: data sensing at the appropriate location and time, wireless transmission of flood data, sensor data fusion, model generation and prediction at the remote weather station. This multidisciplinary research project is addressing each of these areas by employing UK expertise in Water Engineering and Radio Communications to complement the research base in Mexico

    Bone turnover in elderly men: relationships to change in bone mineral density

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    BACKGROUND: It is not clear whether bone turnover markers can be used to make inference regarding changes in bone mineral density (BMD) in untreated healthy elderly men. The present study was designed to address three specific questions: (i) is there a relationship between bone turnover markers and femoral neck BMD within an individual; (ii) is there a relationship between baseline measurements of bone turnover markers and subsequent change in BMD; and (iii) is there a relationship between changes in bone turnover markers and changes in femoral neck BMD? METHODS: The present study was part of the on-going Dubbo Osteoporosis Epidemiology Study, which was designed as a prospective investigation. Men who had had at least 3 sequential visits with serum samples available during follow-up were selected from the study population. Serum C-terminal telopeptide of type I collagen (sICTP), N-terminal propeptide of type I collagen (sPINP) and femoral neck BMD were measured by competitive radioimmunoassays. Femoral neck bone mineral density (BMD) was measured by a densitometer (GE Lunar Corp, Madison, WI). Various mixed-effects models were used to assess the association between the markers and changes in BMD. RESULTS: One hundred and one men aged 70 ± 4.1 years (mean ± SD) met the criteria of selection for analysis. On average, sPINP decreased by 0.7% per year (p = 0.026), sICTP increased by 1.7% per year (p = 0.0002), and femoral neck BMD decreased by 0.4% per year (p < 0.01). Within-subject analysis indicated that changes in BMD were significantly associated with changes in sPINP (p = 0.022), but not with changes in sICTP (p = 0.84). However, neither baseline sPINP (p = 0.50) nor baseline sICTP (p = 0.63) was associated with subsequent changes in BMD. Moreover, changes in BMD were not significantly associated with previous changes in sPINP (p = 0.13) or sICTP (p = 0.95). CONCLUSION: These results suggest that in elderly men of Caucasian background, changes in sPINP were inversely related to changes in BMD within an individual. However, neither sPINP nor sICTP was sufficiently sensitive to predict the rate of change in BMD for a group of individuals or for an individual

    Cancer Treatment and Bone Health

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    Considerable advances in oncology over recent decades have led to improved survival, while raising concerns about long-term consequences of anticancer treatments. In patients with breast or prostate malignancies, bone health is a major issue due to the high risk of bone metastases and the frequent prolonged use of hormone therapies that alter physiological bone turnover, leading to increased fracture risk. Thus, the onset of cancer treatment-induced bone loss (CTIBL) should be considered by clinicians and recent guidelines should be routinely applied to these patients. In particular, baseline and periodic follow-up evaluations of bone health parameters enable the identification of patients at high risk of osteoporosis and fractures, which can be prevented by the use of bone-targeting agents (BTAs), calcium and vitamin D supplementation and modifications of lifestyle. This review will focus upon the pathophysiology of breast and prostate cancer treatment-induced bone loss and the most recent evidence about effective preventive and therapeutic strategies
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