41 research outputs found
Coulomb Blockade in low mobility nanometer size Si:MOSFETs
We investigate coherent transport in Si:MOSFETs with nominal gate lengths 50
to 100nm and various widths at very low temperature. Independent of the
geometry, localized states appear when G=e^{2}/h and transport is dominated by
resonant tunnelling through a single quantum dot formed by an impurity
potential. We find that the typical size of the relevant impurity quantum dot
is comparable to the channel length and that the periodicity of the observed
Coulomb blockade oscillations is roughly inversely proportional to the channel
length. The spectrum of resonances and the nonlinear I-V curves allow to
measure the charging energy and the mean level energy spacing for electrons in
the localized state. Furthermore, we find that in the dielectric regime, the
variance var(lng) of the logarithmic conductance lng is proportional to its
average value consistent with one-electron scaling models.Comment: 4 pages, 4 figure
The management of diabetic ketoacidosis in children
The object of this review is to provide the definitions, frequency, risk factors, pathophysiology, diagnostic considerations, and management recommendations for diabetic ketoacidosis (DKA) in children and adolescents, and to convey current knowledge of the causes of permanent disability or mortality from complications of DKA or its management, particularly the most common complication, cerebral edema (CE). DKA frequency at the time of diagnosis of pediatric diabetes is 10%–70%, varying with the availability of healthcare and the incidence of type 1 diabetes (T1D) in the community. Recurrent DKA rates are also dependent on medical services and socioeconomic circumstances. Management should be in centers with experience and where vital signs, neurologic status, and biochemistry can be monitored with sufficient frequency to prevent complications or, in the case of CE, to intervene rapidly with mannitol or hypertonic saline infusion. Fluid infusion should precede insulin administration (0.1 U/kg/h) by 1–2 hours; an initial bolus of 10–20 mL/kg 0.9% saline is followed by 0.45% saline calculated to supply maintenance and replace 5%–10% dehydration. Potassium (K) must be replaced early and sufficiently. Bicarbonate administration is contraindicated. The prevention of DKA at onset of diabetes requires an informed community and high index of suspicion; prevention of recurrent DKA, which is almost always due to insulin omission, necessitates a committed team effort
ULK1 inhibition overcomes compromised antigen presentation and restores antitumor immunity in LKB1-mutant lung cancer
Inactivating mutations in LKB1/STK11 are present in roughly 20% of nonsmall cell lung cancers (NSCLC) and portend poor response to anti-PD-1 immunotherapy. Unexpectedly, we found that LKB1 deficiency correlated with elevated tumor mutational burden (TMB) in NSCLCs from nonsmokers and genetically engineered mouse models, despite the frequent association between high-TMB and anti-PD-1 treatment efficacy. However, LKB1 deficiency also suppressed antigen processing and presentation, which are associated with compromised immunoproteasome activity and increased autophagic flux. Immunoproteasome activity and antigen presentation were restored by inhibiting autophagy through targeting the ATG1/ULK1 pathway. Accordingly, ULK1 inhibition synergized with PD-1 antibody blockade, provoking effector T-cell expansion and tumor regression in Lkb1-mutant tumor models. This study reveals an interplay between the immunoproteasome and autophagic catabolism in antigen processing and immune recognition, and proposes the therapeutic potential of dual ULK1 and PD-1 inhibition in LKB1-mutant NSCLC as a strategy to enhance antigen presentation and to promote antitumor immunity
Bio-analytical Assay Methods used in Therapeutic Drug Monitoring of Antiretroviral Drugs-A Review
Selective lamina dysregulation in granular retrosplenial cortex (area 29) after anterior thalamic lesions: an in situ hybridization and trans-neuronal tracing study in rats
Can consumers enforce environmental regulations? The role of the market in hazardous waste compliance
We examine the U.S. hazardous waste management industry to assess the role that consumers play in encouraging environmental compliance. We first examine whether environmental performance affects consumer demand and find that noncompliance does decrease demand, at least in the short term. Next we consider whether market characteristics affect compliance behavior. While we do not find evidence that market size affects behavior, local competition does appear to increase compliance. However, as competition becomes less localized, it has a smaller effect. Finally, regardless of the pressures exerted by consumers to comply, commercial managers are less likely to be in compliance than on-site managers. Copyright Springer Science+Business Media, LLC 2007Commercial environmentalism, Compliance, Enforcement, Hazardous waste, Market size, Competition, Q28, K42, D21,
Alzheimer's disease after remote head injury: an incidence study.
OBJECTIVE: To evaluate a history of remote head injury as a risk factor for subsequent dementia due to Alzheimer's disease. METHODS: 271 participants of a community based longitudinal study of aging in north Manhattan without evidence of significant cognitive impairment were interrogated for a history of head injury on two occasions at entry into the study. The examining physician sought a history of head injury with loss of conciousness. Independently, a risk factor interviewer inquired about a history of head injury with loss of consiousness or amnesia, the duration of any loss of consiousness, and the date of the head injury. Patients were followed up with standardised annual evaluations for up to five years to determine the first occurrence of dementia. RESULTS: Over the course of the study incident dementia due to probable or possible Alzheimer's disease was diagnosed in 39 patients. Cox proportional hazards modelling showed that a history of head injury with loss of consiousness reported to the physician was associated with earlier onset of dementia due to Alzheimer's disease (relative risk (RR) = 4.1, 95% confidence interval (95% CI) 1.3-12.7). head injury with loss of consiousness or amnesia reported to the risk factor interviewer was not significantly associated with earlier onset of Alzheimer's disease overall (RR 2.0, 95% CI 0.7-6.2), but those who reported loss of consiousness exceeding five minutes were at significantly increased risk (RR 11.2, 95% CI 2.3-59.8). Incident Alzheimer's disease was significantly associated with head injury which occurred within the preceding 30 years (RR 5.4, 95% CI 1.5-19.5). CONCLUSION: The results of this cohort study are consistent with the findings of several case-control studies suggesting that head injury may be a risk factor for Alzheimer's disease