321 research outputs found

    Transformation of Symmetrization Order to Nuclear-Spin Magnetization by Chemical Reaction and Nuclear Magnetic Resonance

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    A method of obtaining very large nuclear-spin polarizations is proposed and illustrated by density-operator calculations. The prediction is that chemical reaction and rf irradiation can convert the scalar parahydrogen state into polarization of order unity on the nuclear spins of the products of molecular-hydrogen addition reactions. A means of extending the resultant sensitivity enhancement to other spins is proposed in which the transfer of order occurs through population differences not associated with magnetization

    Mid-Atlantic Wind - Overcoming the Challenges

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    This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development

    Genomic analysis of diet composition finds novel loci and associations with health and lifestyle

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    We conducted genome-wide association study (GWAS) meta-analyses of relative caloric intake from fat, protein, carbohydrates and sugar in over 235,000 individuals. We identified 21 approximately independent lead SNPs. Relative protein intake exhibits the strongest relationships with poor health, including positive genetic associations with obesity, type 2 diabetes, and heart disease ( ≈ 0.15 − 0.5). Relative carbohydrate and sugar intake have negative genetic correlations with waist circumference, waist-hip ratio, and neighborhood poverty (|| ≈ 0.1 − 0.3). Overall, our results show that the relative intake of each macronutrient has a distinct genetic architecture and pattern of genetic correlations suggestive of health implications beyond caloric content

    Large variations in the prices of urologic procedures at academic medical centers 1 year after implementation of the Price Transparency Final Rule

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    IMPORTANCE: Patients with urologic diseases often experience financial toxicity, defined as high levels of financial burden and concern, after receiving care. The Price Transparency Final Rule, which requires hospitals to disclose both the commercial and cash prices for at least 300 services, was implemented to facilitate price shopping, decrease price dispersion, and lower health care costs. OBJECTIVE: To evaluate compliance with the Price Transparency Final Rule and to quantify variations in the price of urologic procedures among academic hospitals and by insurance class. DESIGN, SETTING, AND PARTICIPANTS: This was a cross-sectional study that determined the prices of 5 common urologic procedures among academic medical centers and by insurance class. Prices were obtained from the Turquoise Health Database on March 24, 2022. Academic hospitals were identified from the Association of American Medical Colleges website. The 5 most common urologic procedures were cystourethroscopy, prostate biopsy, laparoscopic radical prostatectomy, transurethral resection of the prostate, and ureteroscopy with laser lithotripsy. Using the corresponding Current Procedural Terminology codes, the Turquoise Health Database was queried to identify the cash price, Medicare price, Medicaid price, and commercial insurance price for these procedures. EXPOSURES: The Price Transparency Final Rule, which went into effect January 1, 2021. MAIN OUTCOMES AND MEASURES: Variability in procedure price among academic medical centers and by insurance class (Medicare, Medicaid, commercial, and cash price). RESULTS: Of 153 hospitals, only 20 (13%) listed a commercial price for all 5 procedures. The commercial price was reported most often for cystourethroscopy (86 hospitals [56%]) and least often for laparoscopic radical prostatectomy (45 hospitals [29%]). The cash price was lower than the Medicare, Medicaid, and commercial price at 24 hospitals (16%). Prices varied substantially across hospitals for all 5 procedures. There were significant variations in the prices of cystoscopy (χ23 = 85.9; P = .001), prostate biopsy (χ23 = 64.6; P = .001), prostatectomy (χ23 = 24.4; P = .001), transurethral resection of the prostate (χ23 = 51.3; P = .001), and ureteroscopy with laser lithotripsy (χ23 = 63.0; P = .001) by insurance type. CONCLUSIONS AND RELEVANCE: These findings suggest that, more than 1 year after the implementation of the Price Transparency Final Rule, there are still large variations in the prices of urologic procedures among academic hospitals and by insurance class. Currently, in certain situations, health care costs could be reduced if patients paid out of pocket. The Centers for Medicare & Medicaid Services may improve price transparency by better enforcing penalties for noncompliance, increasing penalties, and ensuring that hospitals report prices in a way that is easy for patients to access and understand

    Prophages encode phage-defense systems with cognate self-immunity

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    Temperate phages are pervasive in bacterial genomes, existing as vertically inherited islands termed prophages. Prophages are vulnerable to predation of their host bacterium by exogenous phages. Here, we identify BstA, a family of prophage-encoded phage-defense proteins in diverse Gram-negative bacteria. BstA localizes to sites of exogenous phage DNA replication and mediates abortive infection, suppressing the competing phage epidemic. During lytic replication, the BstA-encoding prophage is not itself inhibited by BstA due to self-immunity conferred by the anti-BstA (aba) element, a short stretch of DNA within the bstA locus. Inhibition of phage replication by distinct BstA proteins from Salmonella, Klebsiella, and Escherichia prophages is generally interchangeable, but each possesses a cognate aba element. The specificity of the aba element ensures that immunity is exclusive to the replicating prophage, preventing exploitation by variant BstA-encoding phages. The BstA protein allows prophages to defend host cells against exogenous phage attack without sacrificing the ability to replicate lytically

    The PHENIX Experiment at RHIC

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    The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

    Clinical Outcomes and Patient-Matched Molecular Composition of Relapsed Medulloblastoma

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    PURPOSE We sought to investigate clinical outcomes of relapsed medulloblastoma and to compare molecular features between patient-matched diagnostic and relapsed tumors. METHODS Children and infants enrolled on either SJMB03 (NCT00085202) or SJYC07 (NCT00602667) trials who experienced medulloblastoma relapse were analyzed for clinical outcomes, including anatomic and temporal patterns of relapse and postrelapse survival. A largely independent, paired molecular cohort was analyzed by DNA methylation array and next-generation sequencing. RESULTS A total of 72 of 329 (22%) SJMB03 and 52 of 79 (66%) SJYC07 patients experienced relapse with significant representation of Group 3 and wingless tumors. Although most patients exhibited some distal disease (79%), 38% of patients with sonic hedgehog tumors experienced isolated local relapse. Time to relapse and postrelapse survival varied by molecular subgroup with longer latencies for patients with Group 4 tumors. Postrelapse radiation therapy among previously nonirradiated SJYC07 patients was associated with long-term survival. Reirradiation was only temporizing for SJMB03 patients. Among 127 patients with patient-matched tumor pairs, 9 (7%) experienced subsequent nonmedulloblastoma CNS malignancies. Subgroup (96%) and subtype (80%) stabilities were largely maintained among the remainder. Rare subgroup divergence was observed from Group 4 to Group 3 tumors, which is coincident with genetic alterations involving MYC, MYCN, and FBXW7. Subgroup-specific patterns of alteration were identified for driver genes and chromosome arms. CONCLUSION Clinical behavior of relapsed medulloblastoma must be contextualized in terms of up-front therapies and molecular classifications. Group 4 tumors exhibit slower biological progression. Utility of radiation at relapse is dependent on patient age and prior treatments. Degree and patterns of molecular conservation at relapse vary by subgroup. Relapse tissue enables verification of molecular targets and identification of occult secondary malignancies

    A distance of a point from a line

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    U ovom članku razmatra se metoda računanja udaljenosti točke od eksplicitno, parametarski, te polarno zadane krivulje. U literaturi za ovaj problem postoji eksplicitno rješenje za slučaj afine funkcije, te za još neke specijalne slučajeve.This article considers the method for calculating the distance of a point to the curve given explicitly, in parameter and polar form. In literature, there exists an explicit solution to this problem for the case of affine fuctions as well as for some other special cases

    Rat Nucleus Accumbens Core Astrocytes Modulate Reward and the Motivation to Self-Administer Ethanol after Abstinence

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    Our understanding of the active role that astrocytes play in modulating neuronal function and behavior is rapidly expanding, but little is known about the role that astrocytes may play in drug-seeking behavior for commonly abused substances. Given that the nucleus accumbens is critically involved in substance abuse and motivation, we sought to determine whether nucleus accumbens astrocytes influence the motivation to self-administer ethanol following abstinence. We found that the packing density of astrocytes that were expressing glial fibrillary acidic protein increased in the nucleus accumbens core (NAcore) during abstinence from EtOH self-administration. No change was observed in the nucleus accumbens shell. This increased NAcore astrocyte density positively correlated with the motivation for ethanol. Astrocytes can communicate with one another and influence neuronal activity through gap-junction hemichannels. Because of this, the effect of blocking gap-junction hemichannels on the motivation for ethanol was examined. The motivation to self-administer ethanol after 3 weeks abstinence was increased following microinjection of gap-junction hemichannel blockers into the NAcore at doses that block both neuronal and astrocytic channels. In contrast, no effect was observed following microinjection of doses that are not thought to block astrocytic channels or following microinjection of either dose into the nucleus accumbens shell. Additionally, the motivation for sucrose after 3 weeks abstinence was unaffected by NAcore gap-junction hemichannel blockers. Next, Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) were selectively expressed in NAcore astrocytes to test the effect of astrocyte stimulation. DREADD activation increased cytosolic calcium in primary astrocytes, facilitated responding for rewarding brain stimulation, and reduced the motivation for ethanol after 3 weeks abstinence. This is the first work to modulate drug-seeking behavior with astrocyte-specific DREADDs. Taken together, our findings demonstrate that NAcore astrocytes can shape the motivation to self-administer ethanol; suggesting that the development of ligands which selectively stimulate astrocytes may be a successful strategy to abate ethanol-seeking behavior
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