154 research outputs found
Correct quantum chemistry in a minimal basis from effective Hamiltonians
We describe how to create ab-initio effective Hamiltonians that qualitatively
describe correct chemistry even when used with a minimal basis. The
Hamiltonians are obtained by folding correlation down from a large parent basis
into a small, or minimal, target basis, using the machinery of canonical
transformations. We demonstrate the quality of these effective Hamiltonians to
correctly capture a wide range of excited states in water, nitrogen, and
ethylene, and to describe ground and excited state bond-breaking in nitrogen
and the chromium dimer, all in small or minimal basis sets
Development of Risk Prediction Equations for Incident Chronic Kidney Disease
IMPORTANCE Early identification of individuals at elevated risk of developing chronic kidney disease (CKD) could improve clinical care through enhanced surveillance and better management of underlying health conditions.OBJECTIVE To develop assessment tools to identify individuals at increased risk of CKD, defined by reduced estimated glomerular filtration rate (eGFR).DESIGN, SETTING, AND PARTICIPANTS Individual-level data analysis of 34 multinational cohorts from the CKD Prognosis Consortium including 5 222 711 individuals from 28 countries. Data were collected from April 1970 through January 2017. A 2-stage analysis was performed, with each study first analyzed individually and summarized overall using a weighted average. Because clinical variables were often differentially available by diabetes status, models were developed separately for participants with diabetes and without diabetes. Discrimination and calibration were also tested in 9 external cohorts (n = 2 253 540).EXPOSURES Demographic and clinical factors.MAIN OUTCOMES AND MEASURES Incident eGFR of less than 60 mL/min/1.73 m(2).RESULTS Among 4 441 084 participants without diabetes (mean age, 54 years, 38% women), 660 856 incident cases (14.9%) of reduced eGFR occurred during a mean follow-up of 4.2 years. Of 781 627 participants with diabetes (mean age, 62 years, 13% women), 313 646 incident cases (40%) occurred during a mean follow-up of 3.9 years. Equations for the 5-year risk of reduced eGFR included age, sex, race/ethnicity, eGFR, history of cardiovascular disease, ever smoker, hypertension, body mass index, and albuminuria concentration. For participants with diabetes, the models also included diabetes medications, hemoglobin A(1c), and the interaction between the 2. The risk equations had a median C statistic for the 5-year predicted probability of 0.845 (interquartile range [IQR], 0.789-0.890) in the cohorts without diabetes and 0.801 (IQR, 0.750-0.819) in the cohorts with diabetes. Calibration analysis showed that 9 of 13 study populations (69%) had a slope of observed to predicted risk between 0.80 and 1.25. Discrimination was similar in 18 study populations in 9 external validation cohorts; calibration showed that 16 of 18 (89%) had a slope of observed to predicted risk between 0.80 and 1.25.CONCLUSIONS AND RELEVANCE Equations for predicting risk of incident chronic kidney disease developed from more than 5 million individuals from 34 multinational cohorts demonstrated high discrimination and variable calibration in diverse populations. Further study is needed to determine whether use of these equations to identify individuals at risk of developing chronic kidney disease will improve clinical care and patient outcomes.</p
Do Adolescents Like School-Based Mindfulness Training? Predictors of Mindfulness Practice and Responsiveness in the MYRIAD Trial
Objective: We explored what predicts secondary school studentsâ mindfulness practice and responsiveness to universal school-based mindfulness training (SBMT), and how students experience SBMT. Method: A mixed-methods design was used. Participants were 4,232 students (11-13 years of age), in 43 UK secondary schools, who received universal SBMT (ie, â.bâ program), within the MYRIAD trial (ISRCTN86619085). Following previous research, student, teacher, school, and implementation factors were evaluated as potential predictors of studentsâ out-of-school mindfulness practice and responsiveness (ie, interest in and attitudes toward SBMT), using mixed-effects linear regression. We explored pupilsâ SBMT experiences using thematic content analysis of their answers to 2 free-response questions, 1 question focused on positive experiences and 1 question on difficulties/challenges. Results: Students reported practicing out-of-school mindfulness exercises on average once during the intervention (mean [SD] = 1.16 [1.07]; range, 0-5). Studentsâ average ratings of responsiveness were intermediate (mean [SD] = 4.72 [2.88]; range, 0-10). Girls reported more responsiveness. High risk of mental health problems was associated with lower responsiveness. Asian ethnicity and higher school-level economic deprivation were related to greater responsiveness. More SBMT sessions and better quality of delivery were associated with both greater mindfulness practice and responsiveness. In terms of studentsâ experiences of SBMT, the most frequent themes (60% of the minimally elaborated responses) were an increased awareness of bodily feelings/sensations and increased ability to regulate emotions. Conclusion: Most students did not engage with mindfulness practice. Although responsiveness to the SMBT was intermediate on average, there was substantial variation, with some youth rating it negatively and others rating it positively. Future SBMT developers should consider co-designing curricula with students, carefully assessing the student characteristics, aspects of the school environment, and implementation factors associated with mindfulness practice and responsiveness. SBMT teacher training is key, as more observed proficiency in SBMT teaching is associated with greater student mindfulness practice and responsiveness to SBMT
Streptococcus pneumoniae in Biofilms Are Unable to Cause Invasive Disease Due to Altered Virulence Determinant Production
It is unclear whether Streptococcus pneumoniae in biofilms are virulent and contribute to development of invasive pneumococcal disease (IPD). Using electron microscopy we confirmed the development of mature pneumococcal biofilms in a continuous-flow-through line model and determined that biofilm formation occurred in discrete stages with mature biofilms composed primarily of dead pneumococci. Challenge of mice with equal colony forming units of biofilm and planktonic pneumococci determined that biofilm bacteria were highly attenuated for invasive disease but not nasopharyngeal colonization. Biofilm pneumococci of numerous serotypes were hyper-adhesive and bound to A549 type II pneumocytes and Detroit 562 pharyngeal epithelial cells at levels 2 to 11-fold greater than planktonic counterparts. Using genomic microarrays we examined the pneumococcal transcriptome and determined that during biofilm formation S. pneumoniae down-regulated genes involved in protein synthesis, energy production, metabolism, capsular polysaccharide (CPS) production, and virulence. We confirmed these changes by measuring CPS by ELISA and immunoblotting for the toxin pneumolysin and the bacterial adhesins phosphorylcholine (ChoP), choline-binding protein A (CbpA), and Pneumococcal serine-rich repeat protein (PsrP). We conclude that biofilm pneumococci were avirulent due to reduced CPS and pneumolysin production along with increased ChoP, which is known to bind C-reactive protein and is opsonizing. Likewise, biofilm pneumococci were hyper-adhesive due to selection for the transparent phase variant, reduced CPS, and enhanced production of PsrP, CbpA, and ChoP. These studies suggest that biofilms do not directly contribute to development of IPD and may instead confer a quiescent mode of growth during colonization
Meta-analysis of genome-wide association studies identifies common susceptibility polymorphisms for colorectal and endometrial cancer near SH2B3 and TSHZ1
High-risk mutations in several genes predispose to both colorectal cancer (CRC) and endometrial cancer (EC). We therefore hypothesised that some lower-risk genetic variants might also predispose to both CRC and EC. Using CRC and EC genome-wide association series, totalling 13,265 cancer cases and 40,245 controls, we found that the protective allele [G] at one previously-identified CRC polymorphism, rs2736100 near TERT, was associated with EC risk (odds ratio (OR)â=â1.08, Pâ=â0.000167); this polymorphism influences the risk of several other cancers. A further CRC polymorphism near TERC also showed evidence of association with EC (ORâ=â0.92; Pâ=â0.03). Overall, however, there was no good evidence that the set of CRC polymorphisms was associated with EC risk, and neither of two previously-reported EC polymorphisms was associated with CRC risk. A combined analysis revealed one genome-wide significant polymorphism, rs3184504, on chromosome 12q24 (ORâ=â1.10, Pâ=â7.23âĂâ10â9) with shared effects on CRC and EC risk. This polymorphism, a missense variant in the gene SH2B3, is also associated with haematological and autoimmune disorders, suggesting that it influences cancer risk through the immune response. Another polymorphism, rs12970291 near gene TSHZ1, was associated with both CRC and EC (ORâ=â1.26, Pâ=â4.82âĂâ10â8), with the alleles showing opposite effects on the risks of the two cancers
Common variation near CDKN1A, POLD3 and SHROOM2 influences colorectal cancer risk
We performed a meta-analysis of five genome-wide association studies to identify common variants influencing colorectal cancer (CRC) risk comprising 8,682 cases and 9,649 controls. Replication analysis was performed in case-control sets totaling 21,096 cases and 19,555 controls. We identified three new CRC risk loci at 6p21 (rs1321311, near CDKN1A; P = 1.14 Ă 10(-10)), 11q13.4 (rs3824999, intronic to POLD3; P = 3.65 Ă 10(-10)) and Xp22.2 (rs5934683, near SHROOM2; P = 7.30 Ă 10(-10)) This brings the number of independent loci associated with CRC risk to 20 and provides further insight into the genetic architecture of inherited susceptibility to CRC.Swedish Research Council et al.Manuscrip
Development of Risk Prediction Equations for Incident Chronic Kidney Disease
IMPORTANCE â Early identification of individuals at elevated risk of developing chronic kidney diseaseÂ
could improve clinical care through enhanced surveillance and better management of underlying healthÂ
conditions.Â
OBJECTIVE â To develop assessment tools to identify individuals at increased risk of chronic kidneyÂ
disease, defined by reduced estimated glomerular filtration rate (eGFR).Â
DESIGN, SETTING, AND PARTICIPANTS â Individual level data analysis of 34 multinational cohorts fromÂ
the CKD Prognosis Consortium including 5,222,711 individuals from 28 countries. Data were collected from April, 1970 through January, 2017. A twoâstage analysis was performed, with each study firstÂ
analyzed individually and summarized overall using a weighted average. Since clinical variables were often differentially available by diabetes status, models were developed separately within participantsÂ
with diabetes and without diabetes. Discrimination and calibration were also tested in 9 externalÂ
cohorts (N=2,253,540).
EXPOSURE Demographic and clinical factors.Â
MAIN OUTCOMES AND MEASURES â Incident eGFR <60 ml/min/1.73 m2.Â
RESULTS â In 4,441,084 participants without diabetes (mean age, 54 years, 38% female), there wereÂ
660,856 incident cases of reduced eGFR during a mean followâup of 4.2 years. In 781,627 participantsÂ
with diabetes (mean age, 62 years, 13% female), there were 313,646 incident cases during a mean
followâup of 3.9 years. Equations for the 5âyear risk of reduced eGFR included age, sex, ethnicity, eGFR,
history of cardiovascular disease, ever smoker, hypertension, BMI, and albuminuria. For participantsÂ
with diabetes, the models also included diabetes medications, hemoglobin A1c, and the interactionÂ
between the two. The risk equations had a median C statistic for the 5âyear predicted probability ofÂ
0.845 (25th â 75th percentile, 0.789â0.890) in the cohorts without diabetes and 0.801 (25th â 75th
percentile, 0.750â0.819) in the cohorts with diabetes. Calibration analysis showed that 9 out of 13 (69%)
study populations had a slope of observed to predicted risk between 0.80 and 1.25. Discrimination wasÂ
similar in 18 study populations in 9 external validation cohorts; calibration showed that 16 out of 18
(89%) had a slope of observed to predicted risk between 0.80 and 1.25.
CONCLUSIONS AND RELEVANCE â Equations for predicting risk of incident chronic kidney disease
developed in over 5 million people from 34 multinational cohorts demonstrated high discrimination andÂ
variable calibration in diverse populations
Population genomics of the Wolbachia endosymbiont in Drosophila melanogaster
Wolbachia are maternally-inherited symbiotic bacteria commonly found in
arthropods, which are able to manipulate the reproduction of their host in
order to maximise their transmission. Here we use whole genome resequencing
data from 290 lines of Drosophila melanogaster from North America, Europe and
Africa to predict Wolbachia infection status, estimate cytoplasmic genome copy
number, and reconstruct Wolbachia and mtDNA genome sequences. Complete
Wolbachia and mitochondrial genomes show congruent phylogenies, consistent with
strict vertical transmission through the maternal cytoplasm and imperfect
transmission of Wolbachia. Bayesian phylogenetic analysis reveals that the most
recent common ancestor of all Wolbachia and mitochondrial genomes in D.
melanogaster dates to around 8,000 years ago. We find evidence for a recent
incomplete global replacement of ancestral Wolbachia and mtDNA lineages, which
is likely to be one of several similar incomplete replacement events that have
occurred since the out-of-Africa migration that allowed D. melanogaster to
colonize worldwide habitats.Comment: 41 pages, 5 figure
Association of genetic susceptibility variants for type 2 diabetes with breast cancer risk in women of European ancestry.
Purpose: Type 2 diabetes (T2D) has been reported to be associated with an elevated risk of breast cancer. It is unclear, however, whether this association is due to shared genetic factors.
Methods: We constructed a genetic risk score (GRS) using risk variants from 33 known independent T2D susceptibility loci and evaluated its relation to breast cancer risk using the data from two consortia, including 62,328 breast cancer patients and 83,817 controls of European ancestry. Unconditional logistic regression models were used to derive adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) to measure the association of breast cancer risk with T2D GRS or T2D-associated genetic risk variants. Meta-analyses were conducted to obtain summary ORs across all studies.
Results: The T2D GRS was not found to be associated with breast cancer risk, overall, by menopausal status, or for estrogen receptor positive or negative breast cancer. Three T2D associated risk variants were individually associated with breast cancer risk after adjustment for multiple comparisons using the Bonferroni method (at p < 0.001), rs9939609 (FTO) (OR 0.94, 95 % CI = 0.92â0.95, p = 4.13Eâ13), rs7903146 (TCF7L2) (OR 1.04, 95 % CI = 1.02â1.06, p = 1.26Eâ05), and rs8042680 (PRC1) (OR 0.97, 95 % CI = 0.95â0.99, p = 8.05Eâ04).
Conclusions: We have shown that several genetic risk variants were associated with the risk of both T2D and breast cancer. However, overall genetic susceptibility to T2D may not be related to breast cancer risk
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