bluuebunny/crossref_metadata_2025 huggingface dataset:
Proton–synchrotron as the radiation mechanism of the prompt emission of gamma-ray bursts?
Authors: Ghisellini G. , Ghirlanda G. , Oganesyan G. , Ascenzi S. , Nava L. , Celotti A. , Salafia O. S. , Ravasio M. E. , Ronchi M.
Published: February 2020

We discuss the new surprising observational results that indicate quite convincingly that the prompt emission of gamma-ray bursts (GRBs) is due to synchrotron radiation produced by a particle distribution that has a low-energy cut-off. The evidence of this is provided by the low-energy part of the spectrum of the prompt emission, which shows the characteristic Fν ∝ ν1/3 shape followed by Fν ∝ ν−1/2 up to the peak frequency. This implies that although the emitting particles are in fast cooling, they do not cool completely. This poses a severe challenge to the basic ideas about how and where the emission is produced, because the incomplete cooling requires a small value of the magnetic field to limit synchrotron cooling, and a large emitting region to limit the self-Compton cooling, even considering Klein–Nishina scattering effects. Some new and fundamental ingredient is required for understanding the GRBs prompt emission. We propose proton–synchrotron as a promising mechanism to solve the incomplete cooling puzzle.
Tibiaschaftfrakturen
Authors: Al-Sadi Onays , Schaser Klaus-Dieter , Kleber Christian
Published: February 2020

Die Tibiaschaftfraktur ist eine der häufigsten Frakturen langer Röhrenknochen. Bei polytraumatisierten Patienten ist mit dem Vorhandensein von Tibiaschaftfrakturen zu rechnen. Dieser Artikel stellt das diagnostische und therapeutische Vorgehen dar und weist auf die möglichen Komplikationen hin.
Is the level of diffusion restriction in celiac and cervico-thoracic sympathetic ganglia helpful in their proper recognition on PSMA ligand PET/MR?
Authors: Bialek Ewa J. , Malkowski Bogdan
Published: February 2020

Aim To check if diffusion weighted imaging (DWI) might be helpful in proper recognition of celiac (CG) and cervicothoracic (CTG) sympathetic ganglia on the whole-body multimodal PSMA-ligand PET/MR imaging, in the view of their common misleading avidity on PET potentially suggestive of malignant lesions, including metastatic lymph nodes.

Methods The thickness and the level of diffusion restriction was assessed qualitatively and quantitatively in 406 sympathetic ganglia (189 CTG in 101 males and 217 CG in 116 males) on DWI maps (b-value 0 and 800 s/mm2) and apparent diffusion coefficient (ADC) maps (mean ADC) of the whole-body PET/MR 68Ga-PSMA-11 PET/MR. To form a reference group of a matching ganglia size, the smallest lymph node was chosen from each patient with metastases and underwent the same procedure.

Results Very low and low level of diffusion restriction was noted in the majority of sympathetic ganglia (81.0 % CTG, 67.3 % CG, and 73.6 % of all). In the majority (91.7 %) of metastatic lymph nodes the level of diffusion restriction was moderate to high.

The mean ADC values in sympathetic ganglia were statistically significantly higher in CTG, CG and all ganglia than in metastatic lymph nodes (p < 0.001; the effect size was large).

Conclusions Sympathetic celiac and cervicothoracic ganglia present very low and low level of diffusion restriction in visual DWI assessment, and significantly higher than metastatic lymph nodes mean ADC values in the majority of cases, which may serve as additional factors aiding differential diagnosis on multimodal PSMA-ligand PET/MR imaging.

Therefore, PSMA-ligand PET/MR appears potentially superior to PSMA-ligand PET/CT in proper identification of sympathetic ganglia.
Acid-Mediated Denitrogenation/Rearrangement/Coupling of ­Benzyl Azides with Triazolyl-Substituted Cycloalkanones
Authors: Fu Ying , Du Zhengyin , Che Yang , Wang Rui
Published: February 2020

Organic molecules containing α-triazolyl or β-amino cyclic ketone fragments have been individually proven to show good bioactivities and to be useful in asymmetric and pharmaceutical syntheses. A triflic acid-promoted simple and efficient method for the synthesis of unsymmetrical α-triazolyl-α′-(aminomethyl)cycloalkanones from benzyl azides and α-triazolylcycloalkanones has been developed. A series of unsymmetrical α,α′-disubstituted cycloalkanones were obtained with high syn-diastereoselectivity and up to 82% yield. Examination of the reaction mechanism showed that the benzyl azides undergo protonation, nitrogen elimination, rearrangement, and electrophilic attack by the enol forms of the cyclic ketones.
Prosthetic Reconstruction of Superior Vena Cava System for Thymic Tumor: A Retrospective Analysis of 22 Cases
Authors: Zhang Zhenglong , Huang Minhui , Pan Xiaojie
Published: February 2020

Objective This study aimed to report our experience in superior vena cava (SVC) resection and reconstruction for 22 thymic tumor patients and to make comparisons with previous related reports.

Methods A retrospective study on 22 patients (15 thymomas, 7 thymic cancers) who underwent tumor resection with concomitant SVC reconstruction. All the patients underwent vascular conduit reconstruction by the cross-clamping technique. The corresponding data were reviewed, including clinical presentation, operation management (surgery procedure, selection of suitable graft, strategies against SVC syndrome, etc.), postoperative cares (antithrombotic agent application, treatments on brain edema, etc.), and follow-up information.

Result Two patients were myasthenic, well controlled by oral pyridostigmine. All resections were radical (R0). Ten patients received induction treatment. All the 15 thymoma patients were Masaoka stage III (type B1–B3). As for thymic cancer, six patients were Masaoka stage III and one was stage IVa. Wedge pulmonary resection was performed in three patients (two right upper lobe, one both upper lobe). Procedures included were single graft replacement in 12 patients, bilateral grafts in 9, and Y-shaped graft in 1 patient. Anticoagulation and dehydration agents were routinely applied after operation. No perioperative mortalities were observed. Major complication rate was 9.1%. The median survival time was 44.2 months (range, 4–92 months). Three- and 5-year overall survival rates were 80.8 and 44.0%, respectively. As for conduit patency, two grafts (9.1%) demonstrated evidence of occlusion during long-term follow-up, but no additional interventions were required due to no complications related.

Conclusion Our study, confirming data from existing literature, showed that the prosthetic reconstruction of the SVC system is a feasible additional procedure during resection of thymic tumor infiltrating the venous mediastinal axis, minimally increasing postoperative complications in experienced hands.
The Superficial Inferior Epigastric Artery Fascia Flap in Rats
Authors: Saffari Tiam M. , Bishop Allen T. , Shin Alexander Y.
Published: February 2020

Background An adipofascial flap in the rat may provide new options for adding vascularization to scarred or nonvascularized beds for a variety of research studies. Current literature lacks sufficient description for a simple reproducible flap model for a vascularized pedicled flap in rats, in particular for neovascularization of allograft nerves for the reconstruction of sciatic nerve defects. The purpose of this study was to describe a surgical technique and determine long-term survivability for the pedicled superficial inferior epigastric artery fascial (SIEF) flap in the rat to meet requirement for a tunneled adipofascial flap to add vascularization to the sciatic nerve area.

Methods The technique and use of a 4 × 3-cm SIEF flap are described. Twenty Lewis rats underwent the technique to determine feasibility. The flap was wrapped around processed allograft nerve reconstructions and viability of the flap was evaluated after 12 and 16 weeks. To visualize vessels, nerve grafts were harvested at 12 weeks and stained with hematoxylin-eosin and an antibody against microvessels (CD-34).

Results All flaps remained viable after survival of 12 and 16 weeks. Complications included one hematoma formation and two lymphocele formations that did not have any impact on the flap. Immunohistochemistry confirmed an increase in microvessels and Schwann cell nuclei in the SIEF group compared with nerve samples from the unoperated, contralateral side.

Conclusion A pedicled adipofascial flap model in the rat to provide a vascular bed for sciatic nerve reconstruction is detailed with long-term survivability evaluation of the flap. This flap is technically simple to be harvested and is suitable for revascularization procedures of various tissues in the lower abdomen, genital area, thigh, or upper limb of the rat.
Comparison of Shaping Ability of Different Single-File Systems Using Microcomputed Tomography
Authors: Elashiry Mohamed Mohamed , Saber Shehab Eldin , Elashry Salma Hasan
Published: February 2020

Objectives To evaluate the shaping ability of four different single-file systems using micro-computed tomography (micro-CT).

Materials and Methods Eighty mesiobuccal and mesiolingual canals of permanent mandibular molars were randomly assigned to four groups according to the file used; WaveOne Gold, RECIPROC Blue, HyFlex EDM, and One Shape (n = 20). The samples were scanned using micro-CT for the preinstrumentation record; then the canals were instrumented and scanned for the postinstrumentation records.

Statistical Analysis The data were then analyzed statistically using one-way analysis of variance (ANOVA) with the level of significance set at α = 0.05.

Results The results of canal centering ratio and canal transportation showed that no significant difference was found among the four file groups at the middle and the coronal levels. However, a significant difference was found at the apical level (p < 0.05), where WaveOne Gold showed the best centering ratio and the least amount of canal transportation. The change in the canal volume was significant at the coronal level (p < 0.05), whereas the change in the canal volume was higher for the HyFlex EDM group than the other groups. No significant difference was found between the other groups at the apical level, middle level, or in the total percentage of canal volume.

Conclusion WaveOne Gold produced a more centralized canal preparation with a lesser amount of transportation at the apical level. HyFlex EDM showed the highest canal volumetric change at the coronal level. The interim design of the endodontic files has a high impact on the behavior of the file inside the root canal.
Anisotropic viscoelastic phase separation in polydisperse hard rods leads to nonsticky gelation
Authors: Ferreiro-Córdova Claudia , Royall C. Patrick , van Duijneveldt Jeroen S.
Published: February 2020

Spinodal demixing into two phases having very different viscosities leads to viscoelastic networks—i.e., gels—usually as a result of attractive particle interactions. Here, however, we demonstrate demixing in a colloidal system of polydisperse, rod-like clay particles that is driven by particle repulsions instead. One of the phases is a nematic liquid crystal with a highly anisotropic viscosity, allowing flow along the director, but suppressing it in other directions. This phase coexists with a dilute isotropic phase. Real-space analysis and molecular-dynamics simulations both reveal a long-lived network structure that is locally anisotropic, yet macroscopically isotropic. We show that our system exhibits the characteristics of colloidal gelation, leading to nonsticky gels.
A self-adjusting platinum surface for acetone hydrogenation
Authors: Demir Benginur , Kropp Thomas , Rivera-Dones Keishla R. , Gilcher Elise B. , Huber George W. , Mavrikakis Manos , Dumesic James A.
Published: February 2020

Significance

A collaborative approach containing reaction kinetics measurements under steady-state and transient conditions, electronic structure calculations employing density-functional theory, and microkinetic modeling on acetone hydrogenation is employed to provide insights into understanding the self-adjusting platinum surface for the hydrogenation of oxygenates over a wide range of reaction conditions. Elucidation of the repulsive interactions and the corresponding self-adjusting catalyst surface properties at various reaction conditions provides a basis to formulate rate expressions for heterogeneous catalytic processes used in the chemical industry.
Putrescine affects tomato growth and response of antioxidant defense system due to exposure to cinnamic acid
Authors: Yadav  , Singh  , Singh  , Singh  , Hussain
Published: February 2020

The present study deals with the mitigating effects of putrescine (Put) against cinnamic acid (CA). Cinnamic acid in root and shoot exudates of tomato (Solanum lycopersicum L.) acts as an autotoxin, inhibiting growth and metabolic activities. Put has significant role in plant
growth and development, as well as in defense against abiotic and biotic challenges. There are no reports on mitigation of allelopathic effects due to CA by Put. Tomato seedlings exposed to CA decreased root and shoot length, fresh and dry weights, photosynthetic pigments, protein and sugar
contents, and nitrate reductase activity. These parameters increased when Put were applied in combination with CA and alone. Lipid peroxidation enhanced in seedlings treated with CA, but decreased in combined CA-Put treatment. Histochemical staining indicated that CA-induced oxidative damage
which is evident from the presence of reactive oxygen species (ROS) such as O2– and H2O2 in tomato leaves. Put decreased ROS activity and plays promising role in regulation of antioxidant enzyme activities against production of free radicals
and improved seedling growth exposed to CA. Put induced tolerance of tomato seedlings to CA autotoxicity was reflected through enhanced growth of the seedlings. Our findings reveal that Put is efficient to mitigate the allelopathic and adverse effects of CA and buttressed the defense system
of tomato and eliminated the autotoxic effects of endogenous CA in tomato.
The Disparate Impact of Up-or-Out Promotion Policy on Fertility Timing
Authors: Park Kyung H , Rim Nayoung
Published: February 2020

There is growing evidence that childbirth can have especially adverse effects on the career advancement of women. Our study examines how this affects the fertility decisions of men and women on the partner track. We use the After the JD study, a rich panel data set on a nationally representative sample of lawyers, and find that women are more likely than men to delay their first child until after the promotion decision is resolved. This difference in fertility timing is not easily explained by gender-based sorting; however, descriptive evidence suggests that reduced employer investment in mothers and social norms that tie women to child care are relevant mechanisms.
Protein recognition of immobilized ligands: promotion of selective adsorption.
Authors: Hutchens T W , Porath J O
Published: February 2020

We are using simple immobilized ligands to evaluate the biochemistry and mechanisms of selective, high-affinity, protein adsorption events. Several specific means have recently been developed to more selectively utilize the favorable entropy changes associated with the displacement of protein-bound water during the formation and stabilization of protein-ligand recognition events. For protein and peptide immobilization these include, besides hydrophobic interaction, for example, metal ion, pi-electron-mediated, and thiophilic interactions. This latter type of protein-ligand recognition process represents a previously unrecognized interaction mechanism of considerable selectivity, affinity, and utility. Specific examples of the above-mentioned principles and protein fractionations include (a) thiophilic adsorption of immunoglobulins to achieve immunoglobulin-free serum for in vitro production and purification of monoclonal antibodies and (b) urea-induced binding of estrogen-receptor proteins to immobilized DNA. The interaction mechanisms are discussed in terms of the molecular architecture of protein surfaces. We present possibilities for the further utilization of these immobilized ligands and their associated proteins in the areas of clinical biochemistry and immunology.
Immunological capture of nucleic acid hybrids and application to nonradioactive DNA probe assay.
Authors: Rashtchian A , Eldredge J , Ottaviani M , Abbott M , Mock G , Lovern D , Klinger J , Parsons G
Published: February 2020

Antibodies specific for DNA:RNA hybrids were coated onto polystyrene test tubes and applied to hybridization assays involving DNA and RNA. Synthetic DNA probes complementary to 16S rRNA of Campylobacter were labeled with biotin and hybridized to ribosomal RNA directly in lysates of bacterial cells. After hybridization, DNA:RNA hybrids were captured with immobilized anti-DNA:RNA antibody, and the biotinylated probe was detected with streptavidin-horseradish peroxidase (EC 1.11.1.7) conjugate. The assay was optimized to detect as few as 70,000 Campylobacter cells in a sample. We compared the utility of this hybridization assay with that of conventional microbiology methods by examination of 1448 stool samples from hospital clinical laboratories. The DNA hybridization assay had a sensitivity of 98.7% (75/76) and a specificity of 98.2% (1347/1372) and overall agreed with 98.2% of the conventional results for a test population that had a 5.2% incidence (76/1448) of Campylobacter infection. The assay is simple to perform and yields results within 2.5 h.
"Architextured" fluid management of biological liquids.
Authors: Columbus R L , Palmer H J
Published: February 2020

Novel "architextured" liquid-spreading and capillary flow systems are described as an adjunct to diagnostic procedures that range from the fully automated to techniques requiring no instrumentation. These systems were developed because of the observation that local features of macroscopic surfaces--roughness and chemical heterogeneity--influence both the spreading rate and equilibrium shape of liquid drops on solid surfaces. By use of organized patterns of surface structure complemented by surface chemical modification, this uncontrolled and undirected capillary flow is recast into flow behavior that is remarkably reproducible. Flow fronts are engineered to have prescribed shapes, and flow rates that are insensitive to the rheological properties of the biological liquids are obtained. To demonstrate the utility of fluid-management principles, we describe the implementation of architextured capillary configurations in microvolume liquid dispensers and potentiometric analytical systems.
Performance of an in-vivo, continuous blood-gas monitor with disposable probe.
Authors: Miller W W , Yafuso M , Yan C F , Hui H K , Arick S
Published: February 2020

A fluorescence-based fiber optic measurement system has been developed for monitoring pH, pCO2, and pO2 through a 20-gauge radial artery catheter without compromising capabilities for monitoring arterial pressure or for blood withdrawal. The measuring probe consists of three optical fibers to which the sensing chemistries are attached, and a thermocouple that measures temperature. The probe is designed to meet in-vivo biocompatibility requirements for a one-time use of up to 72 h. The components that are in contact with the patient's blood are nontoxic, nonhemolytic, nonthrombogenic, and sterilizable. Blood compatibility is enhanced by including covalently bound heparin. The in-vitro accuracy of the system has been tested against commercial blood-gas measurement instruments; comparison with tonometry and blood gas values gave r greater than or equal to 0.98 for all three sensors. The standard error for all sensors was within the College of American Pathologists' accuracy guidelines for measuring blood gas. Instrumental drift was minimal, indicating that system performance characteristics should not be the limiting factor in obtaining clinically useful information for up to 72 h. The response times of the sensors in animal and in-vitro studies were less than 2 min, suitable for monitoring physiological changes in blood gas values.
Application of novel chromium dioxide magnetic particles to immunoassay development.
Authors: Birkmeyer R C , Diaco R , Hutson D K , Lau H P , Miller W K , Neelkantan N V , Pankratz T J , Tseng S Y , Vickery D K , Yang E K
Published: February 2020

We have used chromium dioxide magnetic particles as the solid support in developing a series of immunological tests. The high surface area (greater than 40 m2/g) available on the magnetic particles and their easy dispersion throughout a solution allow for rapid and complete capture of the target antigen. The magnetic responsiveness of the particles allows for rapid, high-efficiency washing to reduce nonspecific binding, which often limits the sensitivity of serological assays. These features form the basis of extremely rapid and flexible assays for several hormones and markers of cancer and infectious disease. Most of the assays involve monoclonal antibodies. Here we describe specific performance characteristics for thyroxin, follitropin, creatine kinase isoenzyme MB, and antibody to human immunodeficiency virus (HIV). All of the assays are performed in less than 90 min, many in 30 to 45 min. The technology is highly flexible and is suitable for a variety of formats, from manual to fully automated.
Immunoassay of digoxin by differential centrifugation.
Authors: Lentrichia B B , Sciotto-Brown S J , Turanchik M F , Ropiak I K , Yeung K K
Published: February 2020

We describe an immunoassay of digoxin that exploits the differential sedimentation rate between two types of latex particles in a microcentrifugal analyzer. Conventional polystyrene latex particles (relative density = 1.05), sensitized with antibody, are first suspended with the sample and then mixed with digoxin-sensitized latex particles (relative density = 1.5). In the absence of digoxin in the sample, the two particle types bind to each other and, when subjected to centrifugal force, are cleared from the solution simultaneously. In the presence of digoxin, the binding between the particles is inhibited in proportion to the concentration of the drugs; the particles therefore can be differentially sedimented in 1 min. We measured the resulting absorbance to quantify the number of less-heavy particles and used the assay to generate a linear standard curve from 0 to 5 micrograms/L. Because the detection limit of the assay depends on the concentrations of both particle types, we optimized the assay by using two-dimensional analysis. Interference from rheumatoid factor was negligible up to 800 kilo-int. units/L. Precision studies indicated CVs between 5% and 13% within-run and between 4% and 9% for run-to-run in this endpoint assay.
Monoclonal and polyclonal antibodies compared for radioimmunoassay of somatomedin-C in patients with acromegaly or hypopituitarism.
Authors: Burrin J M , Paterson J L , Sharp P S , Yeo T H
Published: February 2020

We used a synthetic recombinant analog of somatomedin-C (Sm-C) to directly compare the performance of polyclonal and monoclonal antibodies for measuring Sm-C in serum of normal persons and in acromegalic or hypopituitary patients. Mean concentrations of Sm-C in healthy adults were 181 (SD 42) micrograms/L as measured with the monoclonal antibody, 194 (SD 61) micrograms/L with the polyclonal antibody. Both antisera gave excellent discrimination between acromegalics and normals. However, the assay with the polyclonal antibody was more sensitive than that with the monoclonal antibody (lower detection limits: 5 vs 100 micrograms/L) and thus better suited for quantifying Sm-C in samples from hypopituitary patients.
Two-monoclonal-antibody "sandwich"-type assay of human lutropin, with no cross reaction with choriogonadotropin.
Authors: Odell W D , Griffin J
Published: February 2020

We have developed a sensitive, specific, noncompetitive sandwich-type assay for human lutropin (hLH). Two monoclonal antibodies are used, and there is no cross reaction with human choriogonadotropin (hCG) or human follitropin (hFSH), and little or none with human thyrotropin (hTSH). There also is no reaction with the free beta chains of hLH and hCG. The detection limit is less than 0.5 int. units of hLH per liter of serum, and the dose-response curve is linear between 0 and 10 int. units/L. The intra-assay CV averaged 5.4% at low doses of hLH; the interassay CV averaged 12.5%.
Determination of tamoxifen and four metabolites in serum by low-dispersion liquid chromatography.
Authors: Lien E A , Ueland P M , Solheim E , Kvinnsland S
Published: February 2020

In this assay of tamoxifen and four metabolites in human serum, the serum samples are deproteinized with an equal volume of acetonitrile, then injected into a small (0.21 X 2 cm) precolumn packed with 5-micron-diameter octadecylsilane (ODS) particles. The samples are concentrated on-column by equilibrating the column with an equivolume solution of water and acetonitrile containing 3 mmol of acetic acid and 2 mmol of diethylamine per liter. The drugs are then directed into an analytical ODS column (0.21 X 10 cm) by changing the mobile phase followed by column switching. The primary alcohol of tamoxifen ("metabolite Y"), 4-hydroxytamoxifen ("metabolite B"), tamoxifen, N-desdimethyltamoxifen ("metabolite Z"), N-desmethyltamoxifen ("metabolite X"), and 4-methoxytamoxifen (internal standard) are eluted in this order at a flow rate of 0.3 mL/min with a mobile phase of acetonitrile/water (91/9 by vol) at low ionic strength (1 mmol of acetic acid and 0.67 mmol of diethylamine per liter) and detected by post-column fluorescence activation by passage through a capillary quartz tube exposed to ultraviolet light. Analytical recovery was close to 100%. Within-day precision corresponded to a CV of 1-5% at serum concentrations of tamoxifen or metabolites greater than 10 micrograms/L; the detection limit of the assay for these compounds was about 1 microgram/L. This fully automated assay has the advantage of simple sample processing, high sample output, low solvent consumption, high analytical recovery of tamoxifen and four metabolites in serum, and determination of all these compounds plus an internal standard in a single run.
A receptor-antibody sandwich assay for teicoplanin.
Authors: Corti A , Cavenaghi L , Giani E , Cassani G
Published: February 2020

We have developed a new method for quantifying teicoplanin in complex matrixes, a receptor-antibody sandwich assay (RASA). The method is based on bioselective adsorption of teicoplanin onto microtiter plates coated with albumin-epsilon-aminocaproyl-D-alanyl-D-alanine, a synthetic analog of its biological target, and reaction with anti-teicoplanin antibodies. The sandwich complexes are detected by incubation with peroxidase-labeled goat antibodies to rabbit IgGs and chromogenic reaction with o-phenylenediamine. The dose-response curve was linear for teicoplanin concentrations in the range from 0 to 0.15 mg/L. We used the assay to measure teicoplanin concentrations in various biological matrixes. Analytical recovery from serum was 99.5%, the interassay CV was 5.1%, and the detection limit was 30 micrograms/L (P less than 0.01). Mean analytical recoveries from other biological specimens were 98% from ascitic fluid, 100% from pleuric liquid, 104.8% from prostate homogenate, and 98.5% from bronchial expectorate.
Turbidimetric measurement of lipase activity--problems and some solutions.
Authors: Tietz N W , Shuey D F , Astles J R
Published: February 2020

We optimized a commercial turbidimetric method for lipase (EC 3.1.1.3) activity (Boehringer Mannheim Diagnostics) and overcame some of its deficiencies. Increasing the bile salt concentration to 35 mmol/L and the colipase concentration to 6 mg/L and using a continuous recording of the reaction-rate curve greatly improved the reaction kinetics, eliminated false results from increases in absorbance, reduced the lag phase, and increased the analytical sensitivity and accuracy. Differentiation of pancreatitis from nonpancreatitis sera by adding NaCl, 140 mmol/L, to the assay mixture to observe the degree of enzyme activation has important limitations. Sera from patients with pancreatitis and only slight or modest increases in lipase behave like sera from healthy individuals or from patients with nonpancreatic disease. The assay shows no interference by lipoprotein lipase and carboxyl esterase. Results compare well by this optimized method and by an optimized "pH-Stat" titrimetric method.
Development and characterization of an automated assay of effective heparin activity in plasma.
Authors: Pierson-Perry J F , Obzansky D M , Mizzer J P
Published: February 2020

We describe a fully automated assay for determining effective heparin activity in plasma, based on heparin-catalyzed inhibition of Factor Xa (EC 3.4.21.6) by antithrombin III (AT III). Residual Factor Xa is determined kinetically by the Du Pont aca discrete clinical analyzer with a chromogenic substrate and is inversely related to heparin activity. Because the test plasma is the sole source of AT III, the assay result is dependent on AT III activity and reflects effective rather than total heparin activity. The assay range is 20-1200 USP units/L, and the assay shows equivalent sensitivity to standard and low-molecular-mass heparins. Within-run reproducibility (CV) is 1.6% at 390 units/L. There was no interference from common blood components or drugs. Results agreed well with those by the Coatest heparin kit (Kabi) adapted to the Cobas-Bio analyzer (r = 0.85, n = 122).
Economy and efficiency in routine thyroid-function testing: use of a sensitive immunoradiometric assay for thyrotropin in a general hospital laboratory.
Authors: Thornes H M , McLeod D T , Carr D
Published: February 2020

We measured thyrotropin (TSH) with a sensitive immunoradiometric assay (IRMA) in 2329 consecutive serum samples received for thyroid-function tests from hospital and general practice. Of these, 185 (7.9%) had TSH values less than 0.2 milli-int. unit/L: 33 (1.4%) were hyperthyroid, 20 (0.9%) were being treated for hyperthyroidism, 115 (4.9%) were receiving L-thyroxin, and 17 (0.7%) were clinically euthyroid but had severe non-thyroidal illnesses. In the first 506 serum samples, we also measured free thyroxin, free triiodothyronine (FT3), and total thyroxin. Thyroliberin (thyrotropin-releasing hormone, TRH) tests performed on 84 patients showed that an undetectable initial TSH (usually ascribable to therapy with thyroxin) predicted a flat TRH response. All untreated thyrotoxic patients had undetectable TSH. Experience confirmed that this TSH assay, in conjunction with a supplementary assay of FT3 when the TSH concentration is less than twice the limit of detection, is efficient and economical for routine evaluation of thyroid function in an unselected population.
Liquid chromatography and radioimmunoassay compared for determination of cortisol and corticosterone in plasma after a dexamethasone suppression test.
Authors: Oka K , Noguchi M , Kitamura T , Shima S
Published: February 2020

We developed sensitive, specific "high-performance" liquid chromatography (HPLC) for determining suppressed cortisol and corticosterone in human plasma and compared its efficacy with that of conventional radioimmunoassay (RIA) at concentrations in the nanogram per liter range. Steroids from a 0.5-mL aliquot of plasma were extracted by rapid-flow fractionation, with diethyl ether as mobile-phase solvent, diatomaceous earth granules as stationary-support material. Analytical recovery of the steroids approached 100%. Concentrations in plasma were determined from peak-height ratio calibration (dexamethasone internal standard). The analytical column contained silica gel and the solvent system was water/methanol/dichloromethane/n-hexane (0.1/3/30/66.9 by vol). We could measure the steroids before and 20 h after oral administration of 0.5 mg of dexamethasone. The detection limit was 300 ng per liter of plasma for corticosterone, 500 ng/L for cortisol, with CVs of less than 4%. Determining corticosterone after administration of dexamethasone, in four of 20 such samples we could determine concentrations greater than 300 ng/L; the others contained corticosterone between 100 and 300 ng/L, but these values could not be certified analytically. Mean concentrations of these hormones as determined by RIA substantially exceeded those by HPLC. Some cross reactions in RIA could not be considered negligible in spite of pre-column treatment of the extracts.
A commercial electrochemical method evaluated for measurement of iron status.
Authors: Skikne B S
Published: February 2020

I evaluated a commercial electrochemical method (Environmental Science Associates), based on potentiostatic coulometry, for determining iron and total iron-binding capacity (TIBC). The method requires 25 and 100 microL of serum, respectively, for these measurements. Serum iron concentrations so determined in 99 normal volunteers satisfactorily correlated with those determined by the Iron Panel Method (Br J Haematol 1978;38:291-4), although the former required correction for lower-than-expected values. The coulometric TIBC results, on the other hand, correlated poorly with those by the Iron Panel Method. However, when the samples for TIBC were prepared according to the Iron Panel Method, by using the magnesium carbonate technique, and then read in the coulometer, there was satisfactory correlation between TIBC values as determined by the two methods. Variability and analytical recovery of the electrochemical method are satisfactory, and the method should be useful for measurement of serum iron when only relatively small volumes of blood are available.
Determination of free digoxin concentrations in serum for monitoring Fab treatment of digoxin overdose.
Authors: Hursting M J , Raisys V A , Opheim K E , Bell J L , Trobaugh G B , Smith T W
Published: February 2020

A rapid method for assessing the free digoxin concentration in the serum of digoxin-overdosed patients receiving treatment with digoxin-specific Fab fragments has been developed. For this method, a protein-free ultrafiltrate is prepared from the patient's serum, and the digoxin in the ultrafiltrate (free digoxin) is measured by fluorescence polarization immunoassay. Both the inaccuracies associated with measurements of total digoxin by immunoassay in the presence of Fab and the long turnaround time associated with measurements of free digoxin by equilibrium dialysis were avoided. Good correlation was observed between measurements of free digoxin by this ultrafiltration technique and by equilibrium dialysis. The ultrafiltration method was used to evaluate the concentrations of free digoxin in a digoxin-overdosed patient treated with Fab at our hospital. In retrospect, the results suggest that her hospital stay could have been shortened by a timely appreciation of her increased concentration of free digoxin. Using the ultrafiltration method, one can determine free digoxin concentrations quickly, conveniently, and accurately in the clinical laboratory. This procedure therefore should be a valuable aid in monitoring the efficacy and adequacy of Fab treatment.
The Ames Clinitek 200/Multistix 9 urinalysis method compared with manual and microscopic methods.
Authors: Grinstead G F , Scott R E , Stevens B S , Ward V L , Wilson D M
Published: February 2020

We assayed 315 urine specimens by the Ames Clinitek 200/Multistix 9 semi-automated method and by corresponding standard methods (listed in parentheses) for the following analytes: protein (sulfosalicylic acid precipitation), glucose (Lilly Tes-Tape), ketones (Boehringer Mannheim Chemstrip K), leukocyte esterase (microscopic examination for leukocytes), blood (microscopic examination for erythrocytes), nitrite (microscopic examination for bacteria, Gram stain, or culture), and pH (pH meter). The Clinitek and standard methods agreed well at all concentrations for protein, ketones, and glucose. The Clinitek leukocyte esterase, nitrite, and blood methods were less sensitive than microscopic methods for detection of pyuria, bacteriuria, and hematuria, respectively. The Clinitek pH method produced falsely low pH values for urines with true pH less than 6.5, and falsely high values for urines with true pH greater than 6.5.
Clinical utility of Ektachem-determined bilirubin fractions for classifying adult inpatients.
Authors: Tetrault G A , Meiklejohn B A , Sparks C E
Published: February 2020

We determined total bilirubin, "direct" and "indirect" bilirubin fractions, and, in parallel, using Ektachem slides, the total, conjugated, unconjugated, and delta bilirubin contents for specimens from 88 adult inpatients at various times during hospitalization in a tertiary-care facility. We wanted to see if the results correlated with the patients' diagnoses, based on a review of medical records and other laboratory data. The patients (including some with mixed disease types) were assigned to one of three predominant disease-process groups: obstructive liver disease, parenchymal liver disease, or hemolytic disease. Ektachem bilirubin fractions and the comparable total, "direct," and "indirect" bilirubin fractions showed equal sensitivity in screening and monitoring disease in all three groups. Measurements of conjugated bilirubin, unconjugated bilirubin, and their sum were sufficient for evaluating bilirubin abnormalities in this complex patient population. Determining delta bilirubin with the total bilirubin slide was rarely useful clinically. Thus, laboratories using Ektachem instrumentation for bilirubin testing can routinely eliminate the extra costs and occasional problems associated with running both bilirubin slides, reserving delta bilirubin determinations for unusual cases.
Optimized liquid-chromatographic method for fluorometric determination of urinary delta-aminolevulinic acid in workers exposed to lead.
Authors: Tomokuni K , Ichiba M , Hirai Y , Hasegawa T
Published: February 2020

We developed a fluorometric method for determining delta-aminolevulinic acid (ALA) in urine of lead workers. A high-performance liquid chromatograph (HPLC) equipped with a fluorescence HPLC monitor is used. The detection limit for aqueous ALA is 20 micrograms/L (15 pmol of ALA in the 100-microL sample). The working linear range of urinary ALA concentration was 0.1 to 100 mg/L. In 25 lead-exposed workers, ALA values by the present method for urine correlated well with those obtained by a conventional colorimetric method (r = 0.996). The advantage of the present method for micro-determination of urinary ALA is its high sensitivity.
Status of drugs-of-abuse testing in urine: An AACC study.
Authors: Frings C S , White R M , Battaglia D J
Published: February 2020

The study demonstrates that, in May 1987, testing urine for drugs of abuse can be accurate. All laboratories challenged in this study currently perform such testing under contract and are involved in monthly proficiency testing and in-service training (AACC's Surveys Plus and In-Service Training Program in Toxicology). The laboratories were challenged to detect drugs at the concentrations at which they accept business. We suspect that when results of studies of this kind have been reported previously, the laboratories may have been scored inaccurately because they used technology designed to detect higher concentrations of the drugs than were weighed into the study specimens. This points up the need for laboratories and clients to be specific about the threshold concentrations used to report positives and policies for reporting positives detected below those concentrations.
MMHub, a database for the mulberry metabolome
Authors: Li Dong , Ma Bi , Xu Xiaofei , Chen Guo , Li Tian , He Ningjia
Published: February 2020

Mulberry is an important economic crop plant and traditional medicine. It contains a huge array of bioactive metabolites such as flavonoids, amino acids, alkaloids and vitamins. Consequently, mulberry has received increasing attention in recent years. MMHub (version 1.0) is the first open public repository of mass spectra of small chemical compounds (<1000 Da) in mulberry leaves. The database contains 936 electrospray ionization tandem mass spectrometry (ESI-MS2) data and lists the specific distribution of compounds in 91 mulberry resources with two biological duplicates. ESI-MS2 data were obtained under non-standardized and independent experimental conditions. In total, 124 metabolites were identified or tentatively annotated and details of 90 metabolites with associated chemical structures have been deposited in the database. Supporting information such as PubChem compound information, molecular formula and metabolite classification are also provided in the MS2 spectral tag library. The MMHub provides important and comprehensive metabolome data for scientists working with mulberry. This information will be useful for the screening of quality resources and specific metabolites of mulberry.

Database URL: https://biodb.swu.edu.cn/mmdb/
Microclimate Temperatures Impact Nesting Preference in Megachile rotundata (Hymenoptera: Megachilidae)
Authors: Wilson Elisabeth S , Murphy Claire E , Rinehart Joseph P , Yocum George , Bowsher Julia H
Published: February 2020

The temperature of the nest influences fitness in cavity-nesting bees. Females may choose nest cavities that mitigate their offspring’s exposure to stressful temperatures. This study aims to understand how cavity temperature impacts the nesting preference of the solitary bee Megachile rotundata (Fabricius) under field conditions. We designed and 3D printed nest boxes that measured the temperatures of 432 cavities. Nest boxes were four-sided with cavity entrances facing northeast, northwest, southeast, and southwest. Nest boxes were placed along an alfalfa field in Fargo, ND and were observed daily for completed nests. Our study found that cavity temperature varied by direction the cavity faced and by the position of the cavity within the nest box. The southwest sides recorded the highest maximum temperatures while the northeast sides recorded the lowest maximum temperatures. Nesting females filled cavities on the north-facing sides faster than cavities on the south-facing sides. The bees preferred to nest in cavities with lower average temperatures during foraging hours, and cavities that faced to the north. The direction the cavity faced was associated with the number of offspring per nest. The southwest-facing cavities had fewer offspring than nests on the northeast side. Our study indicates that the nesting box acts as a microclimate, with temperature varying by position and direction of the cavity. Variation in cavity temperature affected where females chose to nest, but not their reproductive investment.
Development and Validation of Person-Centered Cut-Points for the Figure-of-8-Walk Test of Mobility in Community-Dwelling Older Adults
Authors: Coyle Peter C , Perera Subashan , Shuman Valerie , VanSwearingen Jessie , Brach Jennifer S
Published: February 2020

Background

The Figure-of-8-Walk test (F8WT) is a performance measure of the motor skill of walking. Unlike walking speed over a straight path, it captures curved path walking, which is essential to real-world activity, but meaningful cut-points have yet to be developed for the F8WT.

Methods

A secondary analysis of 421 community-dwelling older adults (mean age 80.7 ± 7.8), who participated in a community-based exercise clinical trial, was performed. Area under receiver operating characteristic curves (AUROCC) were calculated using baseline data, with F8WT performance discriminating different self-reported global mobility and balance dichotomies. Cut-points for the F8WT were chosen to optimize sensitivity and specificity. For validation, F8WT cut-points were applied to postintervention F8WT data. Participants were called monthly for 12 months after intervention completion to record self-reported incident falls, emergency department visits, and hospitalizations; risks of the outcomes were compared between those who performed well and poorly on the F8WT.

Results

F8WT performance times of ≤9.09 seconds and ≤9.27 seconds can discriminate those with excellent (sensitivity = 0.647; specificity = 0.654) and excellent/very good global mobility (sensitivity = 0.649; specificity = 0.648), respectively. A total number of steps ≤17 on the F8WT can discriminate those with excellent/very good/good global balance (sensitivity = 0.646; specificity = 0.608). Compared to those who performed poorly, those who performed well had a lower incidence of negative outcomes: F8WT time ≤9.09 seconds = 46%–59% lower; F8WT time ≤9.27 seconds = 46%–56% lower; F8WT steps ≤17 = 44%–50% lower.

Conclusions

Clinicians may consider these preliminary cut-points to aid in their clinical decision making, but further study is needed for definitive recommendations.
Accelerating numerical wave propagation by wavefield adapted meshes. Part II: full-waveform inversion
Authors: Thrastarson Solvi , van Driel Martin , Krischer Lion , Boehm Christian , Afanasiev Michael , van Herwaarden Dirk-Philip , Fichtner Andreas
Published: February 2020

We present a novel full-waveform inversion (FWI) approach which can reduce the computational cost by up to an order of magnitude compared to conventional approaches, provided that variations in medium properties are sufficiently smooth. Our method is based on the usage of wavefield adapted meshes which accelerate the forward and adjoint wavefield simulations. By adapting the mesh to the expected complexity and smoothness of the wavefield, the number of elements needed to discretize the wave equation can be greatly reduced. This leads to spectral-element meshes which are optimally tailored to source locations and medium complexity. We demonstrate a workflow which opens up the possibility to use these meshes in FWI and show the computational advantages of the approach. We provide examples in 2-D and 3-D to illustrate the concept, describe how the new workflow deviates from the standard FWI workflow, and explain the additional steps in detail.
Generally Stressed Out Bacteria: Environmental Stress Response Mechanisms in Gram-Positive Bacteria
Authors: Bonilla Carla Y
Published: February 2020

The ability to monitor the environment for toxic chemical and physical disturbances is essential for bacteria that live in dynamic environments. The fundamental sensing mechanisms and physiological responses that allow bacteria to thrive are conserved even if the molecular components of these pathways are not. The bacterial general stress response (GSR) represents a conceptual model for how one pathway integrates a wide range of environmental signals, and how a generalized system with broad molecular responses is coordinated to promote survival likely through complementary pathways. Environmental stress signals such as heat, osmotic stress, and pH changes are received by sensor proteins that through a signaling cascade activate the sigma factor, SigB, to regulate over 200 genes. Additionally, the GSR plays an important role in stress priming that increases bacterial fitness to unrelated subsequent stressors such as oxidative compounds. While the GSR response is implicated during oxidative stress, the reason for its activation remains unknown and suggests crosstalk between environmental and oxidative stress sensors and responses to coordinate antioxidant functions. Systems levels studies of cellular responses such as transcriptomes, proteomes, and metabolomes of stressed bacteria and single-cell analysis could shed light into the regulated functions that protect, remediate, and minimize damage during dynamic environments. This perspective will focus on fundamental stress sensing mechanisms and responses in Gram-positive bacterial species to illustrate their commonalities at the molecular and physiological levels; summarize exciting directions; and highlight how system-level approaches can help us understand bacterial physiology.