Three-Dimensional Nanometer Features of Direct Current Electrical Trees in Low-Density Polyethylene.

Electrical trees are one reason for the breakdown of insulating materials in electrical power systems. An understanding of the growth of electrical trees plays a crucial role in the development of reliable high voltage direct current (HVDC) power grid systems with transmission voltages up to 1 MV. A section that contained an electrical tree in low-density polyethylene (LDPE) has been visualized in three dimensions (3D) with a resolution of 92 nm by X-ray ptychographic tomography. The 3D imaging revealed prechannel-formations with a lower density with the width of a couple of hundred nanometers formed around the main branch of the electrical tree. The prechannel structures were partially connected with the main tree via paths through material with a lower density, proving that the tree had grown in a step-by-step manner via the prestep structures formed in front of the main channels. All the prechannel structures had a size well below the limit of the Paschen law and were thus not formed by partial discharges. Instead, it is suggested that the prechannel structures were formed by electro-mechanical stress and impact ionization, where the former was confirmed by simulations to be a potential explanation with electro-mechanical stress tensors being almost of the same order of magnitude as the short-term modulus of low-density polyethylene.

Local Charge Injection and Extraction on Surface-Modified Al2O3 Nanoparticles in LDPE.

We use a recently developed scanning probe technique to image with high spatial resolution the injection and extraction of charge around individual surface-modified aluminum oxide nanoparticles embedded in a low-density polyethylene (LDPE) matrix. We find that the experimental results are consistent with a simple band structure model where localized electronic states are available in the band gap (trap states) in the vicinity of the nanoparticles. This work offers experimental support to a previously proposed mechanism for enhanced insulating properties of nanocomposite LDPE and provides a powerful experimental tool to further investigate such properties.

Therapeutic efficacy in a hemophilia B model using a biosynthetic mRNA liver depot system.

DNA-based gene therapy has considerable therapeutic potential, but the challenges associated with delivery continue to limit progress. Messenger RNA (mRNA) has the potential to provide for transient production of therapeutic proteins, without the need for nuclear delivery and without the risk of insertional mutagenesis. Here we describe the sustained delivery of therapeutic proteins in vivo in both rodents and non-human primates via nanoparticle-formulated mRNA. Nanoparticles formulated with lipids and lipid-like materials were developed for delivery of two separate mRNA transcripts encoding either human erythropoietin (hEPO) or factor IX (hFIX) protein. Dose-dependent protein production was observed for each mRNA construct. Upon delivery of hEPO mRNA in mice, serum EPO protein levels reached several orders of magnitude (>125 000-fold) over normal physiological values. Further, an increase in hematocrit (Hct) was established, demonstrating that the exogenous mRNA-derived protein maintained normal activity. The capacity of producing EPO in non-human primates via delivery of formulated mRNA was also demonstrated as elevated EPO protein levels were observed over a 72-h time course. Exemplifying the possible broad utility of mRNA drugs, therapeutically relevant amounts of human FIX (hFIX) protein were achieved upon a single intravenous dose of hFIX mRNA-loaded lipid nanoparticles in mice. In addition, therapeutic value was established within a hemophilia B (FIX knockout (KO)) mouse model by demonstrating a marked reduction in Hct loss following injury (incision) to FIX KO mice.

Quantification of metallic artifact on CT associated with titanium pedicle screws.

Background: In dogs undergoing vertebral column stabilization, post-operative computed tomography (CT) evaluates implant placement. The impact on the interpretation of metallic artifact associated with titanium implants in dogs remains to be established. Our objective was to quantify metallic artifact on CT associated with titanium pedicle screws. Methods: The study design included an in vitro model and a retrospective review of 11 dogs with vertebral column stabilization. Twenty four titanium pedicle screws (6 each: 2.0 mm, 2.7 mm, 3.5 mm, and 4.5 mm) were inserted into a 20% ballistic gel, and CT scan of the construct was performed. Three blinded raters used a bone window to measure the maximum width (effective size) of each screw, one rater measured effective size using an ultrawide window and 45 titanium pedicle screws (3×2.0 mm, 5×2.7 mm, 30×3.5 mm, and 7×4.5 mm) in 11 clinical cases. Effective size measurements were compared to actual screw sizes. Results: The effective size was 26.9-43.8%, 9.2-18.5%, and 21.1-30.5% larger than the actual size for the in vitro system (bone window), in vitro system (ultrawide window), and clinical cases, respectively. The mean gross difference for the in vitro measurements varied by implant size (p < 0.001) and was positively correlated with implant size (r = 0.846), but the mean percentage difference was negatively correlated with implant size (p < 0.001). Overestimation was larger for the in vitro model bone window compared to the ultrawide window (p < 0.001) and clinical cases (p = 0.001). Conclusion: Metallic artifact associated with titanium pedicle screws on CT resulted in an overestimation of screw size. This information might aid in the interpretation of implant placement on post-operative imaging.

A spectroscopic analysis code for spatially resolved x-ray absorption data from the COAX platform.

Sophisticated tools such as computer vision techniques in combination with 1D lineout type analyses have been used in automating the analysis of spectral data for high energy density (HED) plasmas. Standardized automation can solve the problems posed by the complexity of HED spectra and the quantity of data. We present a spectroscopic code written for automated and streamlined analysis of spatially resolved x-ray absorption data from the COAX platform on Omega-60. COAX uses radiographs and spectroscopic diagnostics to provide shock position and density information. We also obtain the more novel spectral-derived spatial profile of the supersonic radiation flow into a low-density foam. Considerable effort has been spent modernizing our previous spectroscopic analysis method, including the development of new tools characterized by a faster runtime and minimal user input to reduce bias and a testing suite for verifying the accuracy of the various functions within the code. The new code analyzes our spectroscopic images in 1-2 min, with added uncertainty and confidence.

Precise irrigation water and nitrogen management improve water and nitrogen use efficiencies under conservation agriculture in the maize-wheat systems.

A 3-year field experiment was setup to address the threat of underground water depletion and sustainability of agrifood systems. Subsurface drip irrigation (SDI) system combined with nitrogen management under conservation agriculture-based (CA) maize-wheat system (MWS) effects on crop yields, irrigation water productivity (WPi), nitrogen use efficiency (NUE) and profitability. Grain yields of maize, wheat, and MWS in the SDI with 100% recommended N were significantly higher by 15.8%, 5.2% and 11.2%, respectively, than conventional furrow/flood irrigation (CT-FI) system. System irrigation water savings (~ 55%) and the mean WPi were higher in maize, wheat, and MWS under the SDI than CT-FI system. There was saving of 25% of fertilizer N in maize and MWS whereas no saving of N was observed in wheat. Net returns from MWS were significantly higher (USD 265) under SDI with 100% N (with no subsidy) than CT-FI system despite with higher cost of production. The net returns were increased by 47% when considering a subsidy of 80% on laying SDI system. Our results showed a great potential of complementing CA with SDI and N management to maximize productivity, NUE, and WPi, which may be economically beneficial and environmentally sound in MWS in Trans-IGP of South Asia.

Evaluation of Electrosurgery and Diode Laser in Gingival Depigmentation.

Introduction: Gingival depigmentation is a surgical procedure done to eliminate or reduce gingival hyperpigmentation. Various techniques are employed such as scalpel de-epithelization, gingivectomy, electrosurgery, use of chemical agents, cryosurgery, and lasers. The present study was conducted to assess the efficacy of laser and electrosurgical procedure in reducing gingival pigmentation in terms of pain, wound healing, and recurrence of melanin pigmentation. Methodology: A prospective study was conducted on 40 subjects affected by melanin pigmentation. Group I patients were treated with electrosurgery and Group II patients with diode laser procedure. Evaluation for pain was done intraoperatively, 24 hours and 7 days using VAS. Wound healing and recurrence of pigmentation was assessed at one month and three months. Results: No significant difference was noted between the two groups for pain assessment at 7 days with P > 0.001. Both electrosurgery and laser group showed significant differences between intraoperative time period to 24 hours and 24 hours to 7 days at P < 0.001 for pain. Conclusion: Esthetic demands necessitate cosmetic gingival depigmentation procedure. Laser diode photoablation proves to be an effective and reliable technique in achieving the same.

Comparing ascitic aspirate and tissue biopsy in the diagnosis of ovarian malignancy.

The objective of this retrospective study was to assess the role of tissue biopsy in ovarian cancer where a diagnosis had been made from cytological assessment of ascites. A total of 63 women had been coded for ovarian carcinoma during the period; 48 had undergone cytological or histological investigation, of which six had undergone tissue biopsy, despite having had a cytological diagnosis. In all six cases (100%), the tissue biopsy concurred with the original diagnosis. We conclude that, where a clinically- and radiologically-correlated cytological diagnosis is made, the benefits of an invasive procedure to obtain tissue samples do not outweigh the risks to the patient.

Crop nutrient management using Nutrient Expert improves yield, increases farmers' income and reduces greenhouse gas emissions.

Reduction of excess nutrient application and balanced fertilizer use are the key mitigation options in agriculture. We evaluated Nutrient Expert (NE) tool-based site-specific nutrient management (SSNM) in rice and wheat crops by establishing 1594 side-by-side comparison trials with farmers' fertilization practices (FFP) across the Indo-Gangetic Plains (IGP) of India. We found that NE-based fertilizer management can lower global warming potential (GWP) by about 2.5% in rice, and between 12 and 20% in wheat over FFP. More than 80% of the participating farmers increased their crop yield and farm income by applying the NE-based fertilizer recommendation. We also observed that increased crop yield and reduced fertilizer consumption and associated greenhouse gas (GHG) emissions by using NE was significantly influenced by the crop type, agro-ecology, soil properties and farmers' current level of fertilization. Adoption of NE-based fertilizer recommendation practice in all rice and wheat acreage in India would translate into 13.92 million tonnes (Mt) more rice and wheat production with 1.44 Mt less N fertilizer use, and a reduction in GHG of 5.34 Mt CO2e per year over farmers' current practice. Our study establishes the utility of NE to help implement SSNM in smallholder production systems for increasing crop yields and farmers' income while reducing GHG emissions.

Physical map and organization of Arabidopsis thaliana chromosome 4.

A physical map of Arabidopsis thaliana chromosome 4 was constructed in yeast artificial chromosome clones and used to analyze the organization of the chromosome. Mapping of the nucleolar organizing region and the centromere integrated the physical and cytogenetic maps. Detailed comparison of physical with genetic distances showed that the frequency of recombination varied substantially, with relative hot and cold spots occurring along the whole chromosome. Eight repeated DNA sequence families were found in a complex arrangement across the centromeric region and nowhere else on the chromosome.

QSAR studies on benzoylaminobenzoic acid derivatives as inhibitors of beta-ketoacyl-acyl carrier protein synthase III.

Fatty acid biosynthesis is essential for most of the bacterial survival. Components of this biosynthetic pathway have been identified as attractive targets for the development of new antibacterial agents. FabH, beta-ketoacyl-ACP synthase III, is a attractive target since it is central to the initiation of fatty acid biosynthesis. Quantitative structure-activity relationship (QSAR) studies have been carried out on a series of benzoylaminobenzoic acid derivatives as potent inhibitors of FabH and antibacterial activity against Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Enterococcus faecalis, Neisseria meningitidis and Escherichia coli, which demonstrate FabH inhibitory activity in cell free and whole cell system. The QSAR studies revealed that inhibitory activity increases with increase in hydrophobicity, molar refractivity, aromaticity, and presence of OH group (on x position of the nucleus). On the other side presence of hetero-atoms like N, O, or S at R(1) position of the nucleus decreases the inhibitory activity. The comparison of QSAR between the FabH inhibitory activity and antibacterial activity against S. aureus, S. pneumoniae, S. pyogenes, E. faecalis, N. meningitidis also demonstrates that the hydrophobicity, aromaticity and presence of OH group (on x position of the nucleus) are conducive for the inhibitory activity.

Rationalization of physicochemical characters of oxazolyl thiosemicarbazone analogs towards multi-drug resistant tuberculosis: a QSAR approach.

The emergence of multi-drug resistant (MDR) strains of Mycobacterium tuberculosis and the continuing pandemic of tuberculosis emphasizes the urgent need for the development of new and potent anti-tubercular agents. In an effort to develop new and more effective agents to treat tuberculosis emphasis was focused on quantification of structure-activity relationship of oxazolyl thiosemicarbazone derivatives. The de novo analysis gave insight to some important structural features i.e. nitro group on phenyl ring at R(1) position is optimal for the activity and might be responsible for electronic interaction, while phenyl ring at R position interact with the hydrophobic pocket more effectively as compared to unsubstituted or methyl substituted analogs. Hansch approach offered the understanding and parameterization of interactions of the inhibitor with receptor. Similarly QSAR analysis gave some important physicochemical properties, i.e. empirical aromatic index (ARR) and 3D-MoRSE code value of scattering angle at 8A(-1). These two physicochemical properties shall be helpful in the development of more potent analogs.

Development of pharmacophoric model of condensed pyridine and pyrimidine analogs as hydroxymethyl glutaryl coenzyme A reductase inhibitors.

Quantitative structure-activity relationship (QSAR) has been established on a series of thirty-eight compounds of four different sets of condensed pyridine and pyrimidine analogs, for their hydroxymethyl glutaryl coenzyme (HMG-CoA) reductase inhibitor activity, in order to understand the essential structural requirement for binding with receptor, in terms of common biophoric and secondary sites employing APEX-3D software. Among several 3D pharmacophoric models with different sizes and arrangements, one model was selected based on r2 = 0.8, chance<0.001, match equivalent to 0.38 and all the 38 compounds were considered. The results suggest that hydrophobicity, hydrogen acceptor and optimum steric refractivity play a dominant role in the inhibition of HMG-CoA reductase. The information obtained from the present study can be used to design and predict more potent molecules as HMG-CoA reductase inhibitors, prior to their synthesis.

Polyethylene Nanocomposites for the Next Generation of Ultralow-Transmission-Loss HVDC Cables: Insulation Containing Moisture-Resistant MgO Nanoparticles.

The use of MgO nanoparticles in polyethylene for cable insulation has attracted considerable interest, although in humid media the surface regions of the nanoparticles undergo a conversion to a hydroxide phase. A facile method to obtain MgO nanoparticles with a large surface area and remarkable inertness to humidity is presented. The method involves (a) low temperature (400 °C) thermal decomposition of Mg(OH)2, (b) a silicone oxide coating to conceal the nanoparticles and prevent interparticle sintering upon exposure to high temperatures, and (c) heat treatment at 1000 °C. The formation of the hydroxide phase on these silicone oxide-coated MgO nanoparticles after extended exposure to humid air was assessed by thermogravimetry, infrared spectroscopy, and X-ray diffraction. The nanoparticles showed essentially no sign of any hydroxide phase compared to particles prepared by the conventional single-step thermal decomposition of Mg(OH)2. The moisture-resistant MgO nanoparticles showed improved dispersion and interfacial adhesion in the LDPE matrix with smaller nanosized particle clusters compared with conventionally prepared MgO. The addition of 1 wt % moisture-resistant MgO nanoparticles was sufficient to decrease the conductivity of polyethylene 30 times. The reduction in conductivity is discussed in terms of defect concentration on the surface of the moisture-resistant MgO nanoparticles at the polymer/nanoparticle interface.

Highly Efficient Interfaces in Nanocomposites Based on Polyethylene and ZnO Nano/Hierarchical Particles: A Novel Approach toward Ultralow Electrical Conductivity Insulations.

Polyethylene nanocomposites based on functionalized ZnO nano/hierarchical particles with highly effective interfacial surface area are presented, for the next generation of ultralow transmission-loss high-voltage DC insulating materials.

Marked atypical lymphocytosis, hepatitis, and skin rash in sulfasalazine drug allergy.

A 38-year-old man presented with a generalized pruritic maculopapular rash, fever, myalgias, and edema of the face and neck. Laboratory examination revealed eosinophilia, atypical lymphocytosis, and abnormal liver function results. The clinical course was characterized by rapid resolution after initiation of steroid therapy and withdrawal of sulfasalazine, which had been started three weeks earlier for abdominal cramping and diarrhea. This clinical picture suggests a drug-induced hypersensitivity reaction to a drug commonly used for inflammatory bowel disease, sulfasalazine.

Practices of cardiothoracic transplant centers regarding hepatitis C-seropositive candidates and donors.

The purpose of this survey was to determine current practices of cardiothoracic transplant centers regarding transplantation of hearts and lungs into hepatitis C (HCV)-seropositive candidates and the use of organs from HCV-seropositive donors. A telephone survey of 48 cardiothoracic transplant centers was conducted in October 1992. Questions included the center's policy for listing HCV-seropositive candidates; if, and under what conditions, organs from HCV-seropositive donors would be used; and which HCV assays were used. Forty-five programs responded; 75% will list an HCV-seropositive candidate, either directly or by lack of routine screening to exclude such patients; only 16% will not accept HCV-seropositive candidates; 9% had no policy. Overall, 69% will accept organs from HCV-seropositive donors, at least for selected recipients (22% for any recipient, 45% for HCV-seropositive and/or status I recipients; 2% do not screen donors). A total of 27% will never accept organs from an HCV-seropositive donor, and 4% had no policy. Thirty centers provided information on HCV methodology. All but one use a second generation ELISA or EIA as a first-line test. A positive result will be followed by a confirmatory assay/liver biopsy in 42%. The variation in practices reflects the ambiguity in the literature. Adequate evaluation of morbidity and mortality due to HCV infection in this population has not yet been possible, although currently available reports do not show a substantial increase. Prospective controlled trials in cardiothoracic transplant patients are necessary.

Treatment of end-stage chronic obstructive pulmonary disease with double lung transplantation.

Six patients with end-stage emphysema (age 44 +/- 2 years) underwent double lung transplantation (Tx) from June 1988 through May 1990. All suffered from severe inanition and required oxygen therapy. The ischemic time was 193 +/- 28 minutes. Post-Tx immune suppression was OKT3 (14 days), cyclosporine (trough levels of 150 +/- 25 ng/ml), azathioprine to keep WBC at 3,000 to 5,000/cu mm (1 to 3.0 mg/kg/day) and following OKT3, a tapering prednisone regimen. Two rejection episodes that occurred in two patients on post-Tx day 5 and 10 were treated with bolus doses of methylprednisolone. The mean hospital stay was 32 +/- 7 days (range, 20 to 69 days). Four patients required treatment of cytomegalovirus (CMV) infection: gastritis (+donor, +recipient) in one and CMV pneumonia in two (+donor, -recipient). A fourth (+donor, -recipient) had right-sided Candida empyema six weeks post-Tx, developed CMV and staphylococcal sepsis, and died 64 days post-Tx. One patient required pyloroplasty eight weeks post-Tx and one patient underwent tracheal suture line repair at eight weeks. During a follow-up of 81 patients months (range, 8 to 24 months), one patient had developed Epstein-Barr viral (EBV) induced lymphoproliferative disease in the lung and one patient had developed EBV lymphoma. Three patients are at work, one is continuing rehabilitation, and one is at home. Double lung Tx offers a definitive benefit to patients with emphysema; however, a prolonged postoperative course can be expected. Viral infections remain serious but treatable problems.

OKT3 induction and steroid-free maintenance immunosuppression for treatment of high-risk heart transplant recipients.

A group of high-risk heart transplant patients (n = 35) were treated from May 1987 through June 1990, with murine-derived monoclonal CD3 antibody (OKT3) induction therapy and steroid-free maintenance immunosuppression. This group was compared with a group of transplant patients (n = 47) who were not considered high risk and who were treated simultaneously with triple-drug immunosuppression (cyclosporine, azathioprine, and prednisone). The 1- and 3-year actuarial survival rates were similar: 97% and 91% for the OKT3 and 92% and 85% for the triple-drug immunosuppression groups, respectively. The overall incidence of rejection was equal for both groups (56%). No rejection occurred during the OKT3 course and rejection episodes occurred significantly later in patients treated with OKT3, with a mean first rejection episode of 111 +/- 104 days versus 27 +/- 21 days for the triple-drug immunosuppression group (p less than or equal to 0.05). Bacterial infections were seen more frequently (29% vs 6% of the patients treated) in the early period (less than 3 months) in the OKT3 group (p = 0.01) and were associated with the use of mechanical assistance in this group. The incidence of late infections or cytomegalovirus disease was similar for both groups. Patients treated with OKT3 and subsequent steroid-free maintenance immunosuppression had no significant posttransplantation increases of serum cholesterol levels, and hypertension was less common. Initial hospitalization was longer (p less than or equal to 0.05) in the OKT3 group (23 +/- 19 vs 13 +/- 5 days) but after the initial discharge the number of hospital days for the first year was similar for both groups (8 +/- 14 vs 9 +/- 13 days). Ventricular function at 1 year after transplantation was similar for both groups with average ejection fraction of 57% and 59% for the OKT3 and triple-drug immunosuppression groups, respectively. In conclusion, high-risk patients treated with OKT3 and steroid-free maintenance immunosuppression were managed on smaller doses of immunosuppressive drugs in the early postoperative period, and had excellent long-term survival rates. In this group of patients, rejection was delayed and the incidence of hypercholesterolemia, hypertension, and steroid-induced complications was decreased. Such a regimen offers a relatively drug-free period in the early posttransplant stages and freedom from the long-term complications of steroids.