Enhanced triplet superconductivity in next-generation ultraclean UTe2.

The unconventional superconductor UTe[Formula: see text] exhibits numerous signatures of spin-triplet superconductivity-a rare state of matter which could enable quantum computation protected against decoherence. UTe[Formula: see text] possesses a complex phase landscape comprising two magnetic field-induced superconducting phases, a metamagnetic transition to a field-polarized state, along with pair- and charge-density wave orders. However, contradictory reports between studies performed on UTe[Formula: see text] specimens of varying quality have severely impeded theoretical efforts to understand the microscopic origins of the exotic superconductivity. Here, we report a comprehensive suite of high magnetic field measurements on a generation of pristine quality UTe[Formula: see text] crystals. Our experiments reveal a significantly revised high magnetic field superconducting phase diagram in the ultraclean limit, showing a pronounced sensitivity of field-induced superconductivity to the presence of crystalline disorder. We employ a Ginzburg-Landau model that excellently captures this acute dependence on sample quality. Our results suggest that in close proximity to a field-induced metamagnetic transition the enhanced role of magnetic fluctuations-that are strongly suppressed by disorder-is likely responsible for tuning UTe[Formula: see text] between two distinct spin-triplet superconducting phases.

Quantum Interference between Quasi-2D Fermi Surface Sheets in UTe_{2}.

UTe_{2} is a spin-triplet superconductor candidate for which high quality samples with long mean free paths have recently become available, enabling quantum oscillation measurements to probe its Fermi surface and effective carrier masses. It has recently been reported that UTe_{2} possesses a 3D Fermi surface component [Phys. Rev. Lett. 131, 036501 (2023)PRLTAO0031-900710.1103/PhysRevLett.131.036501]. The distinction between 2D and 3D Fermi surface sections in triplet superconductors can have important implications regarding the topological properties of the superconductivity. Here we report the observation of oscillatory components in the magnetoconductance of UTe_{2} at high magnetic fields. We find that these oscillations are well described by quantum interference between quasiparticles traversing semiclassical trajectories spanning magnetic breakdown networks. Our observations are consistent with a quasi-2D model of this material's Fermi surface based on prior dHvA-effect measurements. Our results strongly indicate that UTe_{2}-which exhibits a multitude of complex physical phenomena-possesses a remarkably simple Fermi surface consisting exclusively of two quasi-2D cylindrical sections.

Quasi-2D Fermi surface in the anomalous superconductor UTe2.

The heavy fermion paramagnet UTe2 exhibits numerous characteristics of spin-triplet superconductivity. Efforts to understand the microscopic details of this exotic superconductivity have been impeded by uncertainty regarding the underlying electronic structure. Here we directly probe the Fermi surface of UTe2 by measuring magnetic quantum oscillations in pristine quality crystals. We find an angular profile of quantum oscillatory frequency and amplitude that is characteristic of a quasi-2D Fermi surface, which we find is well described by two cylindrical Fermi sheets of electron- and hole-type respectively. Additionally, we find that both cylindrical Fermi sheets possess considerable undulation but negligible small-scale corrugation, which may allow for their near-nesting and therefore promote magnetic fluctuations that enhance the triplet pairing mechanism. Importantly, we find no evidence for the presence of any 3D Fermi surface sections. Our results place strong constraints on the possible symmetry of the superconducting order parameter in UTe2.

Positron annihilation spectroscopy study of radiation-induced defects in W and Fe irradiated with neutrons with different spectra.

The paper presents new knowledge on primary defect formation in tungsten (W) and iron (Fe) irradiated by fission and high-energy neutrons at near-room temperature. Using a well-established method of positron-annihilation lifetime-spectroscopy (PALS), it was found that irradiation of W in the fission reactor and by high-energy neutrons from the p(35 MeV)-Be generator leads to the formation of small radiation-induced vacancy clusters with comparable mean size. In the case of Fe, smaller mean size of primary radiation-induced vacancy clusters was measured after irradiation with fission neutrons compared to irradiation with high-energy neutrons from the p(35 MeV)-Be generator. It was found that one of the reasons of the formation of the larger size of the defects with lower density in Fe is lower flux in the case of irradiation with high-energy neutrons from the p(35 MeV)-Be source. The second reason is enhanced defect agglomeration and recombination within the energetic displacement cascade at high energy primary knock-on-atoms (PKAs). This is consistent with the concept of the athermal recombination corrected (arc-dpa) model, although the measured dpa cross-section of both fission neutrons and wide-spectrum high-energy neutrons in W is between the conventional Norgett-Robinson-Torrens (NRT-dpa) and arc-dpa predictions. This means that the physics of the primary radiation effects in materials is still not fully known and requires further study through a combination of modeling and experimental efforts. The present data serve as a basis for the development of an improved concept of the displacement process.

Changes of 6-keto PGF1 alpha concentration in plasma and vessel wall and TxB2 in plasma of whole-body irradiated rats in the early stage of irradiation.

The aim of this work was to monitor concentrations of prostanoids affecting platelet aggregation, namely prostacyclin and thromboxane A2, in the plasma and prostacyclin in the endothelium of vessel wall after whole-body irradiation of rats by the doses 5, 10, 50, 100 and 250 Gy (source 60Co) in the early stage of irradiation up to 24 hours. Stable metabolites of the prostanoids - 6-keto PGF1 alpha and TxB2 were determined by a RIA technique. The 6-keto PGF1 alpha plasma concentration increased after irradiation by the 50 Gy dose between 3rd and 24th hours and at all sampling times after the 100 and 250 Gy doses. A rise in prostanoid concentrations was noted after low doses of irradiation in the first sampling intervals only. The TxB2 level increased after the same doses (5 and 10 Gy) up to the 6th hour and then decreased. The thromboxane concentration increased after 50 Gy at the 90th minute, 12th and 24th hours, after 100 Gy at the 24th hour and after 250 Gy at the 90th minute, 3rd and 24th hours.

Antiferritin antibodies in immunoscintigraphic detection of human tumor xenografts.

Affinity-purified antibodies against human placental ferritin and their F(ab)2 fragments labeled with 131I were examined for suitability for radioimmunodetection of ferritin-containing tumors. The nude mouse model (BALB/c, nu/nu) with xenografts of HeLa cell tumors and human adenocarcinoma of the rectum (with proven ferritin content) was used. Gamma-camera imaging and tissue distribution studies revealed that both kinds of tumor selectively accumulate antiferritin antibodies and their fragments. In large necrotic tumors nonspecific uptake of radiolabeled normal IgG occurred, but otherwise there was no tumor localisation. This study, in accordance with the literature, confirms the utility of antiferritin antibodies for the detection of human tumors in an animal model.

A graphical nomogram method for predicting toxic concentrations of unbound phenytoin.

The graphical nomogram method to estimate the phenytoin free concentration at any selected total serum phenytoin and/or albumin concentrations was applied using Scatchard binding equation. The binding parameters were calculated by the non-linear least-squares regression analysis of the binding data collected from 96 outpatients on common anticonvulsant therapy. Free phenytoin concentration was measured by the Amicon multi-micro ultrafiltration system. The mean values of N and Kapp were found to be: N = 1.03, and Kapp = 18,500 (M-1). Correlation coefficient for relationship between measured and predicted free phenytoin concentrations was very good (r = 0.94), but the results of prediction-error analysis (MPE = 0.153, and RMSE = 0.296) show that the nomogram method overpredicts the measured free phenytoin (PHT) concentration approximately about 10% higher (15-30 mg/l) than serum phenytoin levels.

Oxidative phenotype polymorphism (P450 2D6) and metabolism of toluene.

Oxidative phenotype P-450 2D6 was examined using sparteine test in 3 groups of persons to determine if there is a coincidence in the defect of the oxidative biotransformation of sparteine and impaired oxidation of toluene, which could explain interindividual differences in the amounts of hippuric acid in the urine in exposed persons. The following groups of persons were examined: 30 rotogravure printers exposed to toluene vapors at concentrations of 8-307 ppm; 20 workers, 2 months after the cessation of the long-term exposure to toluene at concentrations of 104-1,170 ppm; 48 healthy volunteers with no exposure to toluene. Among the 98 persons 5 poor metabolizers (PMs) of sparteine were found, none in the group of printers exposed to toluene. In the experimental exposure chamber 5 PMs and 6 extensive metabolizers (EMs) were exposed to toluene concentration of 245 ppm for 5 hours. Hippuric acid and o-cresol in the urine, and toluene both in blood and in alveolar air were measured. However, no significant differences were found in either of these parameters between the PM and EM groups. Thus, the sparteine test does not appear to be applicable in the identification of persons with higher risk arising from toluene exposure.

Changes of lipid-bound sialic acid in the plasma of mice bearing benzpyrene-induced tumors.

The level of lipid-bound sialic acid (LSA) was followed in inbred C57Bl/6 mice bearing tumors induced by benzpyrene at a dose of 20 mg per kg of body weight. In the plasma of mice with macroscopically ascertained tumors, the level of LSA was increased significantly. The LSA level was also significantly increased in the plasma of suspect mice i.e., in a period when the tumor was not yet macroscopically ascertained, however, when a change was observed in the motion of the hind limb of mice to which benzpyrene was administered.

An experimental immunoscintigraphic study with anti-CEA monoclonal antibody (DG2).

Monoclonal antibody D11-DG2 (DG2) against carcinoembryonic antigen (CEA) was examined for suitability for radioimmunodetection of human tumors grown in nude mice. Antibodies DG2 and a control antibody of the same IgG1 subclass were labeled with 131I and injected into mice bearing one of three types of CEA-containing tumors (cell lines LS 174T, HT-29 and Rec S) and/or a CEA-negative tumor (Rec R). Gamma-camera imaging and distribution studies revealed that CEA-containing tumors selectively accumulate DG2 but Rec R does not. As the tumors differ in CEA-content, the highest accumulation of 131I-DG2 (corresponding to the best scintigraphic imaging) was found in LS 174T tumors, intermediate in Rec S and lowest in HT-29 tumors. The mean tumor-to-blood ratios on the sixth day after antibody administration were 4.6, 3.2, and 2.1, respectively, in the control experiments the value of this parameter was always lower than 1. The results showed the applicability of DG2 for immunoscintigraphic studies in patients. Furthermore, a positive correlation was found between the uptake of anti-CEA antibody and CEA-content in the tumors.

A comparison of measurements and CFD model predictions for pollutant dispersion in cities.

An accurate description of car movements in an urban area is required for accurate prediction of the air pollution concentration field. A 3-D Eulerian-Lagrangian approach to moving vehicles that takes into account the traffic-induced flow field and turbulence is presented. The approach is based on Computational Fluid Dynamics (CFD) calculations using Eulerian approach to the continuous phase and Lagrangian approach to the discrete phase of moving objects-vehicles. In the first part of the present contribution, the method is applied to pollutants dispersion in a city tunnel outlet in Brno and to a street structure in Hannover, Germany. In the second part, a model of traffic dynamics inside a street intersection in the centre of Brno is presented. This model accounts for the dynamics of traffic lights and a corresponding traffic-generated flow field and emissions in different time intervals during the traffic light sequence. All results of numerical modelling are compared with field measurements with very good agreement. A commercial CFD code StarCD was used into which the Lagrangian model and traffic dynamics model were integrated.

Tumour localization of radiolabelled monoclonal antibody in mice bearing human urinary bladder (T24) carcinoma xenografts.

Selectivity of mouse monoclonal antibody 7E9 (IGG3) directed against human urinary bladder carcinoma cells has been examined by indirect membrane immunofluorescence, using a panel of 31 human cell lines. The 7E9 monoclonal antibody discriminated between urinary bladder carcinoma cells and normal urothelium or cells of non-urothelial origin, although occasional reactions with bladder carcinoma-unrelated cell types were observed. The 7E9 antibody was purified by protein A affinity chromatography, labeled with 131I and used for gamma scintigraphy in nude mice xenografted with human urinary bladder carcinoma T24. The 7E9 antibody was capable of locating the T24 xenografts in nude mice; it localized preferentially in the T24 tissue compared to normal mouse tissues. The T24 xenografts could not be detected by gamma scintigraphy with 131I-labelled monoclonal antibody against human mammary carcinoma cells and two other control antibodies. Likewise, the 131I-labelled 7E9 antibody was not capable of locating human mammary carcinoma xenografts in nude mice.

[Vitamin C levels in the early postnatal period in calves and their mothers]. / Vitamin C v raném postnatálním období u telat a jejich matek.

The dynamics of L-ascorbic acid was studied in 68 cows and 91 calves at an age from one to ten days in the period from November to April. The study was conducted in two maternal stocks in a supply area of a large-capacity calf-house located in the beet-growing region. L-ascorbic acid in the blood serum was determined accoring to King. The lowest average levels of L-ascorbic acid were found in February (cows 0.35 mg%, calves 1.02 mg%), and the highest in April (cows 1.00 mg%, calves 2.52 mg%). The level of L-ascorbic acid descended during ontogenesis from the value found at birth (6.72 mg%); the values of the first postpartal day are significantly higher in comparison with all the remainind observations. The results constituted a basis for a working hypothesis on the importance of colostrum as an exogenous source of L-ascorbic acid for calves.

[The genetic contribution of cows to the prevalence of mastitis in the following generation]. / Genetický podíl krav na prevalenci mastitid v následující generaci.

Investigations of mastitis prevalence were performed in 1227 dam-daughter pairs during 1985-1988. From the records of the last 10 years, the findings concerning mammary gland were obtained. Six herds of agricultural co-operatives in the Brno region were investigated. In the early period the Bohemian Pied breed, later the crosses of this breed with Red Holstein and a low genetic proportion of Ayrshire cattle, dominated in the set of cows. Udder health was assessed using the clinical and bacteriological findings in individual udder quarters and the results of the rapid mastitis test NK. Based on this data, the cows were divided into two groups--resistant and susceptible. The lactation order in which the disease appeared for the first time was of great importance. The occurrence of the disease in daughters and udder health in dams were in a significant relation (P less than or equal to 0.01). While nearly 50% of daughters of susceptible dams were affected, it was only 25% in daughters of the resistant group. The assessment of heritability of resistance to mastitis was carried out on the principle of dam-daughter regression. The index of heritability h2 = 0.52 +/- 0.06 was calculated. The results show that the genetic contribution of dams to the susceptibility of daughters to mastitis is significant.

[Relation between lipid-bound sialic acid in blood serum and plasma andin human tumors]. / Vztah lipidicky vázané kyseliny sialové v krevním séru a plazme k lidským nádorum.

Athymic mice with transplanted osteosarcoma and carcinoma of the rectum were found to have increased blood plasma levels of lipid-bound sialic acid (LSA). To verify the applicability of the method of LSA determination, patients with cancer of the mammary gland, rectum, and colon were examined for their LSA level. The serum LSA level was significantly increased in patients with cancer of the mammary gland and rectum, compared to levels determined in the serum of healthy volunteers. The serum LSA level elevation was even more pronounced in patients with carcinoma of the colon. In patients with carcinoma of the colon who were in remission at the time of blood collection the serum LSA level was found to be reduced to control values.

[Photodynamic therapy of human tumor xenotransplants in athymic nu/nu mice]. / Fotodynamická terapie lidských nádoru xenotransplantovaných na athymické nu/nu mysi.

The effect of phototherapy on the growth of two human tumors, i.e. carcinoma of the rectum I and III, was studied. The tumors were xenotransplated into athymic nu/nu mice. Meso-tetra-(para-sulfophenyl)-porphin, TPPS4, was used as photosensitizer. Incorporation studies showed the optimal dose for phototherapy to be 10 mg/kg TPPS4 and the time interval 72 hours. Under these experimental conditions (helium-neon laser, 632, 8, 300 J/cm2) one of six tumors was cured in the group with carcinoma of the rectum I, and that both after IV and IT administration of the photosensitizer. The other five experimental animals exhibited only partial responses to phototherapy. In the group with carcinoma of the rectum III, five out of six tumors were cured by IT administration of TPPS4 under the same experimental conditions. In one mouse there was only partial response to phototherapy. After IV administration of TPPS4, however, not a single tumor was cured and the response to phototherapy was only partial in all the six experimental animals.

[Immunoscintigraphy in experiments and clinical practice: its possibilities, advantages and limitations]. / Imunoscintigrafie v experimentu, klinice, její moznosti, výhody a omezení.

The authors present their experience gained in preparing, isolating and labeling antibodies with radionuclides for the purpose of using them in immunoscintigraphy. The experimental part includes results obtained with different labeled antibodies and their F/ab/2 fragments in distribution studies, involving also immunoscintigraphic imaging of tumors. The clinical part presents results of immunoscintigraphy obtained with the commercial antibody kits Iodomab and Imacis in patients with tumors of the digestive tract.

[The role of prostanoids in malignant diseases]. / Uloha prostanoidu pri zhoubných onemocneních.

Prostanoids are substances which are of great regulatory importance for the organism. Recently not only their active participation in the metabolism of malignant tissue is discussed, but also the possibility of their use in the comprehensive treatment of malignant diseases. At present the effect on a reduction of metastases after prostaglandin I2 administration (= prostacycline) as well as of prostaglandin E2 is tested experimentally as they inhibit the capacity of primary tumours to form metastases. The possibility is also considered of using quantitative estimation of some prostanoids for evaluation of the severity of invasion of the organism by a malignant process.

[Comparison of plasmatic and renal clearance of lithium]. / Srovnání plazmatické a renálni clearance lithia.

The authors elaborated a method for assessment of the renal lithium clearance, CLr, the results of which correlate well with the plasmatic clearance (CLp] (r = 0.785, p less than 0.05). This correlation improved substantially after correction of CLr to the clearance of endogenous creatinine, CLcr (r = 0.945; p less than 0.05). The mean values of CLr of the investigated group--26.4 ml/min are in agreement with the results published by other authors. A significant correlation between CLr and CLcr (r = 0.826, p less than 0.05) along with comparison of the intraindividual variability of assessed results indicates that it is better to use as a parameter of sodium absorption from the proximal tubule the fractional lithium clearance rather than absolute values of CLr.

Postirradiation haemorrhagic syndrome.

One of the relevant symptoms of damage due to irradiation are the manifestations of haemorrhagic diathesis. The extravascular effusion of the blood in the course of the course of the irradiation disease may sometimes also be the cause of death of the irradiated individual, it may complicate the course of the arisen disease and sometimes even make any necessary therapeutical help impossible. The postirradiation disorder of haemocoagulation and haemostasis is a process very complicated both in its origin and in its course. Many experimental studies have been devoted to the study of the mechanism of origin of this disorder, of its course and of the possibilities of its therapy and actually we already have some clinical results. For a wider information and for the utilization of the up-to-date findings in practise, we hold it reasonable to summarize, in a certain time period, the information, though of a restricted problem, in order to facilitate an orientation in the contributions research has made up to now and to enable the selection of the adequate direction of the future experimental studies. This was the reason for the compilation of this monograph in which a summary of the up-to-date experience published in the literature and the results of our many-year standing experimental work is presented in the first opening chapter. In the second chapter, the mechanisms of blood clotting in man and the most often used laboratory animals in experiments, i.e. the dog, rabbit, rat and guinea pig, are compared. By a comparison of the platelet counts, of the time of their survival and the modes of reaction to the inductors of aggregation, some differences have been demonstrated between human thrombocytes and those of laboratory animals, which may be partly conditioned by some species specific composition of the glycoproteins of the platelet membrane. Further on, the difficulties in the determination of the levels of the individual coagulation factors are referred to and their values established in man are compared with those found in the examined laboratory animals in which decreased levels of factor VII and markedly elevated levels of factors V and VIII have been demonstrated. Next, the physiological inhibitors of blood clotting in man are compared with similar substances found in the blood of laboratory animals. Some differences in the structure and in the function of these substances slowing down the blood coagulation are stressed.(ABSTRACT TRUNCATED AT 400 WORDS)