525 research outputs found
Dynamical Generation of CKM Mixings by Broken Horizontal Gauge Interactions
The fermion mass matrices are calculated in the framework of the dynamical
mass generation by the broken horizontal gauge interactions. The
non-proportional mass spectra between up- and down-sectors and CKM mixings are
obtained solely by radiative corrections due to the ordinary gauge
interactions.Comment: 20 pages + 1 uuencoded eps figure, PHYZZ
Doping Dependence of the Electronic Structure of Ba_{1-x}K_{x}BiO_{3} Studied by X-Ray Absorption Spectroscopy
We have performed x-ray absorption spectroscopy (XAS) and x-ray photoemission
spectroscopy (XPS) studies of single crystal Ba_{1-x}K_{x}BiO_{3} (BKBO)
covering the whole composition range . Several features in
the oxygen 1\textit{s} core XAS spectra show systematic changes with .
Spectral weight around the absorption threshold increases with hole doping and
shows a finite jump between and 0.40, which signals the
metal-insulator transition. We have compared the obtained results with
band-structure calculations. Comparison with the XAS results of
BaPb_{1-x}Bi_{x}O_{3} has revealed quite different doping dependences between
BKBO and BPBO. We have also observed systematic core-level shifts in the XPS
spectra as well as in the XAS threshold as functions of , which can be
attributed to a chemical potential shift accompanying the hole doping. The
observed chemical potential shift is found to be slower than that predicted by
the rigid band model based on the band-structure calculations.Comment: 8 pages, 8 figures include
Measurement of the Xi-p Scattering Cross Sections at Low Energy
In this paper we report cross-section measurements for elastic and
inelastic scatterings at low energy using a scintillating fiber active target.
Upper limit on the total cross-section for the elastic scattering was found to
be 24 mb at 90% confidence level, and the total cross section for the
reaction was found to be mb. We
compare the results with currently competing theoretical estimates.Comment: 9 page
Enteric Neurospheres Are Not Specific to Neural Crest Cultures: Implications for Neural Stem Cell Therapies
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited
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Phenotypic Spectrum Caused by Transgenic Overexpression of Activated Akt in the Heart
The serine-threonine kinase, Akt, inhibits cardiomyocyte apoptosis acutely both in vitro and in vivo. However, the effects of chronic Akt activation in the heart are unknown. To address this issue, we generated transgenic mice (TG ) with cardiac-specific expression of a constitutively active mutant of Akt (myr-Akt) driven by the myosin heavy chain- promoter. Three TG founders (9–19 weeks) died suddenly with massive cardiac dilatation. Two viable TG lines (TG564 and TG20) derived from independent founders demonstrated cardiac-specific transgene expression as well as activation of Akt and p70S6 kinase. TG564 (n 19) showed cardiac hypertrophy with a heart/body weight ratio 2.3-fold greater than littermates (n 17, p < 0.005). TG20 (n 18) had less marked cardiac hypertrophy with a heart/body weight ratio 1.6-fold greater than littermates (n 17, p < 0.005). Isolated TG564 myocytes were also hypertrophic with surface areas 1.7-fold greater than littermates (p < 0.000001). Echocardiograms in both lines demonstrated concentric hypertrophy and preserved systolic function. After ischemia-reperfusion, TG had a 50% reduction in infarct size versus TG (17 3% versus 34 4%, p < 0.001). Thus, chronic Akt activation is sufficient to cause a spectrum of phenotypes from moderate cardiac hypertrophy with preserved systolic function and cardioprotection to massive cardiac dilatation and sudden death
A Clinical Practice Guideline for the Management of Patients With Degenerative Cervical Myelopathy: Recommendations for Patients With Mild, Moderate, and Severe Disease and Nonmyelopathic Patients With Evidence of Cord Compression.
Study Design: Guideline development. Objectives: The objective of this study is to develop guidelines that outline how to best manage (1) patients with mild, moderate, and severe myelopathy and (2) nonmyelopathic patients with evidence of cord compression with or without clinical symptoms of radiculopathy. Methods: Five systematic reviews of the literature were conducted to synthesize evidence on disease natural history; risk factors of disease progression; the efficacy, effectiveness, and safety of nonoperative and surgical management; the impact of preoperative duration of symptoms and myelopathy severity on treatment outcomes; and the frequency, timing, and predictors of symptom development. A multidisciplinary guideline development group used this information, and their clinical expertise, to develop recommendations for the management of degenerative cervical myelopathy (DCM). Results: Our recommendations were as follows: (1) "We recommend surgical intervention for patients with moderate and severe DCM." (2) "We suggest offering surgical intervention or a supervised trial of structured rehabilitation for patients with mild DCM. If initial nonoperative management is pursued, we recommend operative intervention if there is neurological deterioration and suggest operative intervention if the patient fails to improve." (3) "We suggest not offering prophylactic surgery for non-myelopathic patients with evidence of cervical cord compression without signs or symptoms of radiculopathy. We suggest that these patients be counseled as to potential risks of progression, educated about relevant signs and symptoms of myelopathy, and be followed clinically." (4) "Non-myelopathic patients with cord compression and clinical evidence of radiculopathy with or without electrophysiological confirmation are at a higher risk of developing myelopathy and should be counselled about this risk. We suggest offering either surgical intervention or nonoperative treatment consisting of close serial follow-up or a supervised trial of structured rehabilitation. In the event of myelopathic development, the patient should be managed according to the recommendations above." Conclusions: These guidelines will promote standardization of care for patients with DCM, decrease the heterogeneity of management strategies and encourage clinicians to make evidence-informed decisions
Incidence and risk factors of postoperative neurologic decline after complex adult spinal deformity surgery:results of the Scoli-RISK-1 study
A clinical practice guideline for the management of patients with acute spinal cord injury: recommendations on the use of methylprednisolone sodium succinate
Introduction: The objective of this guideline is to outline the appropriate use of methylprednisolone sodium succinate (MPSS) in patients with acute spinal cord injury (SCI). Methods: A systematic review of the literature was conducted to address key questions related to the use of MPSS in acute SCI. A multidisciplinary Guideline Development Group used this information, in combination with their clinical expertise, to develop recommendations for the use of MPSS. Based on GRADE (Grading of Recommendation, Assessment, Development and Evaluation), a strong recommendation is worded as "we recommend," whereas a weaker recommendation is indicated by "we suggest." Results: The main conclusions from the systematic review included the following: (1) there were no differences in motor score change at any time point in patients treated with MPSS compared to those not receiving steroids; (2) when MPSS was administered within 8 hours of injury, pooled results at 6- and 12-months indicated modest improvements in mean motor scores in the MPSS group compared with the control group; and (3) there was no statistical difference between treatment groups in the risk of complications. Our recommendations were: (1) "We suggest not offering a 24-hour infusion of high-dose MPSS to adult patients who present after 8 hours with acute SCI"; (2) "We suggest a 24-hour infusion of high-dose MPSS be offered to adult patients within 8 hours of acute SCI as a treatment option"; and (3) "We suggest not offering a 48-hour infusion of high-dose MPSS to adult patients with acute SCI." Conclusions: These guidelines should be implemented into clinical practice to improve outcomes and reduce morbidity in SCI patients
A clinical practice guideline for the management of patients with acute spinal cord injury and central cord syndrome: recommendations on the timing (<= 24 hours versus > 24 hours) of decompressive surgery
Objective: To develop recommendations on the timing of surgical decompression in patients with traumatic spinal cord injury (SCI) and central cord syndrome. Methods: A systematic review of the literature was conducted to address key relevant questions. A multidisciplinary guideline development group used this information, along with their clinical expertise, to develop recommendations for the timing of surgical decompression in patients with SCI and central cord syndrome. Based on GRADE, a strong recommendation is worded as "we recommend," whereas a weak recommendation is presented as "we suggest." Results: Conclusions from the systematic review included (1) isolated studies reported statistically significant and clinically important improvements following early decompression at 6 months and following discharge from inpatient rehabilitation; (2) in one study on acute central cord syndrome without instability, a marginally significant improvement in total motor scores was reported at 6 and 12 months in patients managed with early versus late surgery; and (3) there were no significant differences in length of acute care/rehabilitation stay or in rates of complications between treatment groups. Our recommendations were: "We suggest that early surgery be considered as a treatment option in adult patients with traumatic central cord syndrome" and "We suggest that early surgery be offered as an option for adult acute SCI patients regardless of level." Quality of evidence for both recommendations was considered low. Conclusions: These guidelines should be implemented into clinical practice to improve outcomes in patients with acute SCI and central cord syndrome by promoting standardization of care, decreasing the heterogeneity of management strategies, and encouraging clinicians to make evidence-informed decisions
Racial and Ethnic Differences in Individuals with Sporadic Creutzfeldt-Jakob Disease in the United States of America
BACKGROUND: Little is known about racial and ethnic differences in individuals with sporadic Creutzfeldt-Jakob disease (sCJD). The authors sought to examine potential clinical, diagnostic, genetic, and neuropathological differences in sCJD patients of different races/ethnicities. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective study of 116 definite and probable sCJD cases from Johns Hopkins and the Department of Veterans Affairs Healthcare Systems was conducted that examined differences in demographic, clinical, diagnostic, genetic, and neuropathological characteristics among racial/ethnic groups. Age at disease onset differed among racial/ethnic groups. Non-Hispanic Whites had a significantly older age at disease onset compared to the other groups (65 vs. 60, p = 0.036). Non-Whites were accurately diagnosed more rapidly than Whites (p = 0.008) and non-Hispanic Whites were more likely to have normal appearing basal ganglia on brain magnetic resonance imaging (MRI) compared to minorities (p = 0.02). Whites were also more likely to undergo post-mortem evaluation compared to non-Whites (p = 0.02). CONCLUSIONS/SIGNIFICANCE: Racial/ethnic groups affected by sCJD demonstrated differences in age at disease onset, time to correct diagnosis, clinical presentation, and diagnostic test results. Whites were more likely to undergo autopsy compared to non-Whites. These results have implications in regards to case ascertainment, diagnosis, and surveillance of sCJD and possibly other human prion diseases
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