238 research outputs found
Full-Duplex Wireless for 6G: Progress Brings New Opportunities and Challenges
The use of in-band full-duplex (FD) enables nodes to simultaneously transmit
and receive on the same frequency band, which challenges the traditional
assumption in wireless network design. The full-duplex capability enhances
spectral efficiency and decreases latency, which are two key drivers pushing
the performance expectations of next-generation mobile networks. In less than
ten years, in-band FD has advanced from being demonstrated in research labs to
being implemented in standards and products, presenting new opportunities to
utilize its foundational concepts. Some of the most significant opportunities
include using FD to enable wireless networks to sense the physical environment,
integrate sensing and communication applications, develop integrated access and
backhaul solutions, and work with smart signal propagation environments powered
by reconfigurable intelligent surfaces. However, these new opportunities also
come with new challenges for large-scale commercial deployment of FD
technology, such as managing self-interference, combating cross-link
interference in multi-cell networks, and coexistence of dynamic time division
duplex, subband FD and FD networks.Comment: 21 pages, 15 figures, accepted to an IEEE Journa
Analysis of colorectal cancers in British Bangladeshi identifies early onset, frequent mucinous histotype and a high prevalence of RBFOX1 deletion
PMCID: PMC3544714This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Wasps and bees of Bimini
29 p. : ill. ; 24 cm.Includes bibliographical references (p. 29)
Senataxin, defective in ataxia oculomotor apraxia type 2, is involved in the defense against oxidative DNA damage.
A defective response to DNA damage is observed in several human autosomal
recessive ataxias with oculomotor apraxia, including ataxia-telangiectasia. We
report that senataxin, defective in ataxia oculomotor apraxia (AOA) type 2, is a
nuclear protein involved in the DNA damage response. AOA2 cells are sensitive to
H2O2, camptothecin, and mitomycin C, but not to ionizing radiation, and
sensitivity was rescued with full-length SETX cDNA. AOA2 cells exhibited
constitutive oxidative DNA damage and enhanced chromosomal instability in
response to H2O2. Rejoining of H2O2-induced DNA double-strand breaks (DSBs) was
significantly reduced in AOA2 cells compared to controls, and there was no
evidence for a defect in DNA single-strand break repair. This defect in DSB
repair was corrected by full-length SETX cDNA. These results provide evidence
that an additional member of the autosomal recessive AOA is also characterized by
a defective response to DNA damage, which may contribute to the neurodegeneration
seen in this syndrome
Performance criteria for verbal autopsy-based systems to estimate national causes of death: development and application to the Indian Million Death Study.
BACKGROUND: Verbal autopsy (VA) has been proposed to determine the cause of death (COD) distributions in settings where most deaths occur without medical attention or certification. We develop performance criteria for VA-based COD systems and apply these to the Registrar General of India's ongoing, nationally-representative Indian Million Death Study (MDS). METHODS: Performance criteria include a low ill-defined proportion of deaths before old age; reproducibility, including consistency of COD distributions with independent resampling; differences in COD distribution of hospital, home, urban or rural deaths; age-, sex- and time-specific plausibility of specific diseases; stability and repeatability of dual physician coding; and the ability of the mortality classification system to capture a wide range of conditions. RESULTS: The introduction of the MDS in India reduced the proportion of ill-defined deaths before age 70 years from 13% to 4%. The cause-specific mortality fractions (CSMFs) at ages 5 to 69 years for independently resampled deaths and the MDS were very similar across 19 disease categories. By contrast, CSMFs at these ages differed between hospital and home deaths and between urban and rural deaths. Thus, reliance mostly on urban or hospital data can distort national estimates of CODs. Age-, sex- and time-specific patterns for various diseases were plausible. Initial physician agreement on COD occurred about two-thirds of the time. The MDS COD classification system was able to capture more eligible records than alternative classification systems. By these metrics, the Indian MDS performs well for deaths prior to age 70 years. The key implication for low- and middle-income countries where medical certification of death remains uncommon is to implement COD surveys that randomly sample all deaths, use simple but high-quality field work with built-in resampling, and use electronic rather than paper systems to expedite field work and coding. CONCLUSIONS: Simple criteria can evaluate the performance of VA-based COD systems. Despite the misclassification of VA, the MDS demonstrates that national surveys of CODs using VA are an order of magnitude better than the limited COD data previously available
Age-specifi c and sex-specifi c adult mortality risk in India in 2014: analysis of 0·27 million nationally surveyed deaths and demographic estimates from 597 districts
Background As child mortality decreases rapidly worldwide, premature adult mortality is becoming an increasingly
important contributor to global mortality. Any possible worldwide reduction of premature adult mortality before the
age of 70 years will depend on progress in India. Indian districts increasingly have responsibility for implementing
public health programmes. We aimed to assess age-specifi c and sex-specifi c adult mortality risks in India at the
district level.
Methods We analysed data from fi ve national surveys of 0∙27 million adult deaths at an age of 15–69 years together
with 2014 demographic data to estimate age-specifi c and sex-specifi c adult mortality risks for 597 districts. Cause of
death data were drawn from the verbal autopsies in the Registrar General of India’s ongoing Million Death Study.
Findings In 2014, about two-fi fths of India’s men aged 15–69 years lived in the 253 districts where the conditional
probability of a man dying at these ages exceeded 50%, and more than a third of India’s women aged 15–69 years lived
in the 222 districts where the conditional probability of a woman dying exceeded 40%. The probabilities of a man or
woman dying by the age of 70 years in high-mortality districts was 62% and 54%, respectively, whereas the probability
of a man or woman dying by the age of 70 years in low-mortality districts was 40% and 30%, respectively. The roughly
10-year survival gap between high-mortality and low-mortality districts was nearly as extreme as the survival gap between
the entire Indian population and people living in high-income countries. Adult mortality risks at ages 15–69 years was
highest in east India and lowest in west India, by contrast with the north–south divide for child mortality. Vascular
disease, tuberculosis, malaria and other infections, and respiratory diseases accounted for about 60% of the absolute
gap in adult mortality risk at ages 15–69 years between high-mortality and low-mortality districts. Most of the variation
in adult mortality could not be explained by known determinants or risk factors for premature mortality.
Interpretation India’s large variation in adult mortality by district, notably the higher death rates in eastern India,
requires further aetiological research, particularly to explore whether high levels of adult mortality risks from
infections and non-communicable diseases are a result of historical childhood malnutrition and infection. Such
research can be complemented by an expanded coverage of known eff ective interventions to reduce adult mortality,
especially in high-mortality district
MLH1 deficiency leads to deregulated mitochondrial metabolism
The DNA mismatch repair (MMR) pathway is responsible for the repair of base–base mismatches and insertion/deletion loops that arise during DNA replication. MMR deficiency is currently estimated to be present in 15–17% of colorectal cancer cases and 30% of endometrial cancers. MLH1 is one of the key proteins involved in the MMR pathway. Inhibition of a number of mitochondrial genes, including POLG and PINK1 can induce synthetic lethality in MLH1-deficient cells. Here we demonstrate for the first time that loss of MLH1 is associated with a deregulated mitochondrial metabolism, with reduced basal oxygen consumption rate and reduced spare respiratory capacity. Furthermore, MLH1-deficient cells display a significant reduction in activity of the respiratory chain Complex I. As a functional consequence of this perturbed mitochondrial metabolism, MLH1-deficient cells have a reduced anti-oxidant response and show increased sensitivity to reactive oxidative species (ROS)-inducing drugs. Taken together, our results provide evidence for an intrinsic mitochondrial dysfunction in MLH1-deficient cells and a requirement for MLH1 in the regulation of mitochondrial function
Clinical and Molecular Characterization of Ataxia with Oculomotor Apraxia Patients In Saudi Arabia
<p>Abstract</p> <p>Background</p> <p>Autosomal recessive ataxias represent a group of clinically overlapping disorders. These include ataxia with oculomotor apraxia type1 (AOA1), ataxia with oculomotor apraxia type 2 (AOA2) and ataxia-telangiectasia-like disease (ATLD). Patients are mainly characterized by cerebellar ataxia and oculomotor apraxia. Although these forms are not quite distinctive phenotypically, different genes have been linked to these disorders. Mutations in the <it>APTX </it>gene were reported in AOA1 patients, mutations in <it>SETX </it>gene were reported in patients with AOA2 and mutations in <it>MRE11 </it>were identified in ATLD patients. In the present study we describe in detail the clinical features and results of genetic analysis of 9 patients from 4 Saudi families with ataxia and oculomotor apraxia.</p> <p>Methods</p> <p>This study was conducted in the period between 2005-2010 to clinically and molecularly characterize patients with AOA phenotype. Comprehensive sequencing of all coding exons of previously reported genes related to this disorder (<it>APTX</it>, <it>SETX </it>and <it>MRE11</it>).</p> <p>Results</p> <p>A novel nonsense truncating mutation c.6859 C > T, R2287X in <it>SETX </it>gene was identified in patients from one family with AOA2. The previously reported missense mutation W210C in <it>MRE11 </it>gene was identified in two families with autosomal recessive ataxia and oculomotor apraxia.</p> <p>Conclusion</p> <p>Mutations in <it>APTX </it>, <it>SETX </it>and <it>MRE11 </it>are common in patients with autosomal recessive ataxia and oculomotor apraxia. The results of the comprehensive screening of these genes in 4 Saudi families identified mutations in <it>SETX </it>and <it>MRE11 </it>genes but failed to identify mutations in <it>APTX </it>gene.</p
Aberrant Splicing of the Senataxin Gene in a Patient with Ataxia with Oculomotor Apraxia Type 2
Ataxia with oculomotor apraxia type 2 (AOA2) is caused by a diversity of mutations within the coding region of the senataxin gene. Recently, rare noncoding senataxin mutations affecting RNA processing have been identified in AOA2. Here, we report the case of an 18-year-old woman, with classic clinical features of AOA2, who was found to harbor a mutation within senataxin intron 16. This mutation disrupts the local 5′ splice site architecture via a novel intronic frameshift mechanism, causing skipping of exon 16 with predicted disruption of the conserved DNA/RNA helicase domain. RNA processing mutations expand the growing complexity of pathogenic senataxin mutations
Towards an Intelligent Tutor for Mathematical Proofs
Computer-supported learning is an increasingly important form of study since
it allows for independent learning and individualized instruction. In this
paper, we discuss a novel approach to developing an intelligent tutoring system
for teaching textbook-style mathematical proofs. We characterize the
particularities of the domain and discuss common ITS design models. Our
approach is motivated by phenomena found in a corpus of tutorial dialogs that
were collected in a Wizard-of-Oz experiment. We show how an intelligent tutor
for textbook-style mathematical proofs can be built on top of an adapted
assertion-level proof assistant by reusing representations and proof search
strategies originally developed for automated and interactive theorem proving.
The resulting prototype was successfully evaluated on a corpus of tutorial
dialogs and yields good results.Comment: In Proceedings THedu'11, arXiv:1202.453
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