106 research outputs found
Unambiguous quantum state elimination for qubit sequences
Quantum state elimination measurements tell us what states a quantum system does not have. This is different from state discrimination, where one tries to determine what the state of a quantum system is rather than what it is not. Apart from being of fundamental interest, quantum state elimination may find uses in quantum communication and quantum cryptography. We consider unambiguous quantum state elimination for two or more qubits, where each qubit can be in one of two possible states. Optimal measurements for eliminating one and two states out of four two-qubit states are given. We also prove that if we want to maximize the average number of eliminated overall
N
-qubit states, then individual measurements on each qubit are optimal
Genome-Wide Tissue-Specific Occupancy of the Hox Protein Ultrabithorax and Hox Cofactor Homothorax in Drosophila
The Hox genes are responsible for generating morphological diversity along the
anterior-posterior axis during animal development. The
Drosophila Hox gene Ultrabithorax
(Ubx), for example, is required for specifying the identity
of the third thoracic (T3) segment of the adult, which includes the dorsal
haltere, an appendage required for flight, and the ventral T3 leg.
Ubx mutants show homeotic transformations of the T3 leg
towards the identity of the T2 leg and the haltere towards the wing. All Hox
genes, including Ubx, encode homeodomain containing
transcription factors, raising the question of what target genes
Ubx regulates to generate these adult structures. To
address this question, we carried out whole genome ChIP-chip studies to identify
all of the Ubx bound regions in the haltere and T3 leg imaginal discs, which are
the precursors to these adult structures. In addition, we used ChIP-chip to
identify the sites bound by the Hox cofactor, Homothorax (Hth). In contrast to
previous ChIP-chip studies carried out in Drosophila embryos,
these binding studies reveal that there is a remarkable amount of tissue- and
transcription factor-specific binding. Analyses of the putative target genes
bound and regulated by these factors suggest that Ubx regulates many downstream
transcription factors and developmental pathways in the haltere and T3 leg.
Finally, we discovered additional DNA sequence motifs that in some cases are
specific for individual data sets, arguing that Ubx and/or Hth work together
with many regionally expressed transcription factors to execute their functions.
Together, these data provide the first whole-genome analysis of the binding
sites and target genes regulated by Ubx to specify the morphologies of the adult
T3 segment of the fly
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A randomised, factorial trial to reduce arterial stiffness independently of blood pressure: proof of concept? The ‘VaSera’ trial testing dietary nitrate and spironolactone
Aim
To test if spironolactone or dietary nitrate from beetroot juice could reduce arterial stiffness as aortic pulse wave velocity (PWVart), a potential treatment target, independently of blood pressure.
Methods
Daily spironolactone (≤50mg) versus doxazosin (control ≤16mg) and 70mL beetroot juice (‘Beet-It’ ≤11mmol nitrate) versus nitrate-depleted juice (placebo; 0mmol nitrate) were tested in people at risk or with type-2 diabetes using a double-blind, 6-month factorial trial. Vascular indices (baseline, 12, 24 weeks) were cardiac-ankle vascular index (‘CAVI’), a nominally pressure-independent stiffness measure (primary outcome), pulse wave velocity (PWVart) secondary, central systolic pressure and augmentation. Analysis was intention-to-treat, adjusted for systolic pressure differences between trial arms.
Results
Spironolactone did not reduce stiffness, with evidence for reduced CAVI on doxazosin rather than spironolactone (mean difference [95% confidence intervals]; 0.25[-0.3, 0.5] units, p=0.080), firmer for PWVart (0.37[0.01, 0.7] ms-1, p=0.045). There was no difference in systolic pressure reduction between spironolactone and doxazosin (0.7[-4.8, 3.3]mmHg, p=0.7). Circulating nitrate and nitrite increased on active versus placebo juice, with central systolic pressure lowered -2.6[-4.5, - 0.8]mmHg, p=0.007 more on the active juice, but did not reduce CAVI, PWVart, nor peripheral pressure.
Change in nitrate and nitrite concentrations were 1.5-fold [1.1-2.2] and 2.2-fold [1.3, 3.6] higher on spironolactone than on doxazosin respectively; both p<0.05.
Conclusion
Contrary to our hypothesis, in at-risk/type-2 diabetes patients, spironolactone did not reduce arterial stiffness, rather PWVart was lower on doxazosin. Dietary nitrate elevated plasma nitrite, selectively lowering central systolic pressure, observed previously for nitrite
Caracterização do gene vip3A e toxicidade da proteína Vip3Aa50 à lagarta-do-cartucho e à lagarta-da-soja
O objetivo deste trabalho foi caracterizar o gene vip3A de Bacillus thuringiensis e verificar a toxicidade da proteína Vip3Aa50 a larvas da lagarta-do-cartucho (Spodoptera frugiperda) e da lagarta-da-soja (Anticarsia gemmatalis). O gene vip3A foi amplificado por PCR, com iniciadores específicos, e gerou um fragmento de 2.370 pb. Esse fragmento foi clonado em vetor pGEM-T Easy e, em seguida, sequenciado, subclonado em vetor de expressão pET-28a (+) e inserido em células de Escherichia coli BL21 (DE3). A expressão da proteína Vip3Aa50 foi induzida por isopropil-β-D-1-tiogalactopiranosídeo (IPTG), visualizada em SDS-PAGE e detectada por "Western blot". Os ensaios de toxicidade revelaram alta atividade da proteína Vip3Aa50 contra as larvas neonatas da lagarta-da-soja e da lagarta-do-cartucho, com CL50 de 20,3 e 79,6 ng cm-2, respectivamente. O gene vip3Aa50 é um novo gene da classe vip3A
Whole-genome sequencing reveals host factors underlying critical COVID-19
Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2–4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease
Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity
The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)
Genetic mechanisms of critical illness in COVID-19.
Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 × 10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice
Designing Institutions for Diversity
This paper analyzes the design of innovation contests when the quality of an innovation depends on the research approach of the supplier, but the best approach is unknown. Diversity of approaches is desirable because it generates an option value. In our main model with two suppliers, the buyer optimally uses a bonus tournament, where suppliers can choose between a low bid and a high bid. This allows the buyer to implement any level of diversity with the lowest revenue for the suppliers. We also compare other common contests, in particular, fixed-prize tournaments and auctions. Like bonus tournaments, auctions implement the socially optimal diversity, but usually with higher rents for the suppliers. Fixed-prize tournaments implement insufficient diversity, but may nevertheless be preferred by the buyer to auctions because of lower supplier rents
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