Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189  fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3  GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

Measurement of the Λ_{c}^{+} Lifetime

An absolute measurement of the Λ_{c}^{+} lifetime is reported using Λ_{c}^{+}→pK^{-}π^{+} decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2  fb^{-1}. The result, τ(Λ_{c}^{+})=203.20±0.89±0.77  fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.

Bicyclic imidazole-4-one derivatives: a new class of antagonists for the orphan G protein-coupled receptors GPR18 and GPR55

GPR18 and GPR55 are orphan G protein-coupled receptors (GPCRs) that interact with certain cannabinoid (CB) receptor ligands.

A novel cis-peptide bond motif inducing beta-turn type VI. The synthesis of enkephalin analogues modified with 4-aminopyroglutamic acid

A new pathway leading to a mixture of four isomers of 4-aminopyroglutamic acid is described. Michael type addition of Z-deltaAla-OMe to enolates prepared from acylaminomalonates, followed by hydrolysis and decarboxylation give protected 4-aminopyroglutamic acid with the cis:trans ratio approximately 3:2. This mixture was incorporated into Leu-enkephalin (position 2-3). After separation of peptides it appeared that all analogues were essentially inactive in guinea pig ileum and mouse vas deferens bioassays.

A novel cis-peptide bond motif inducing beta-turn type VI. The synthesis of enkephalin analogues modified with 4-aminopyroglutamic acid

A new pathway leading to a mixture of four isomers of 4-aminopyroglutamic acid is described. Michael type addition of Z-deltaAla-OMe to enolates prepared from acylaminomalonates, followed by hydrolysis and decarboxylation give protected 4-aminopyroglutamic acid with the cis:trans ratio approximately 3:2. This mixture was incorporated into Leu-enkephalin (position 2-3). After separation of peptides it appeared that all analogues were essentially inactive in guinea pig ileum and mouse vas deferens bioassays.

Differences in the mineral density of lower limb bone tissue in a healthy population sample

This article presents the results of research to evaluate the impact of the functional asymmetry of the lower limbs on the precision of the densitometric measurements used in the diagnosis of metabolic bone diseases and in monitoring treatment outcomes. The study subject were 46 healthy adults, in whom the mineral density of the bone tissue (BMD) was measured in the proximal epiphysis of the femoral bone in both the left and right lower limb. In 43 of the analyzed cases (94%), higher BMD was found in the dominant extremity (avg. 2,8%, range 0,6-11,8%). Although lateralization of the lower limbs was confirmed in every case in this population sample, no statistically significant differences in BMD were found between the dominant and subdominant limb. However, due to the large differences in BMD found in individual cases, control DEXA measurements should always be taken from the same side when monitoring the outcome of metabolic bone disease treatment in individual patients.

The most common errors in the densitometric diagnosis of osteoporosis

A review of world literature on the subject indicates that, given the present state of our knowledge, and the technological possibilities and availability of the apparatus, the most useful method for the evaluation of bone metabolism, especially the diagnosis of osteoporosis, is dual energy X-ray absorptiometry (DEXA). However, this method is not free of errors that can exert a negative impact on the final results of examination. On the basis of heir own experience, the authors have presented here the most common errors encountered in the densitometric technique. A DPV-L densitometric apparatus (Lunar Corporation) was used in this research. Errors in densitometric testing are divided into three groups: those dependent on the object investigated, those dependent on densitometric data analysis, and others. In the first group we took into account factors which can lead to either overestimating (+) or underestimating (-) the final test results: degenerative changes (+), scoliosis (+), the presence of foreign bodies, such as metal (-), status post fracture (+), the presence of pathological structures (+ or -), osteoporotic fractures (+), and incorrect arrangement of the investigated object (+ or -). Errors in data analysis included erroneous data entry regarding the patient's age, height, body mass (affecting the value of the Z-score), and sex (distorting the T-score and the Z-score), and incorrect settings regarding the measurement field. Other errors to densitometric technique included failure to calibrate or improper calibration of the measurement apparatus and errors in computer programming. Individual errors were responsible for falsifying results from 1 to 37%. If several of these errors are accumulated, the accuracy of examination may change more than 100%. Densitometric examinations of the lumbar spine are the most subject to error. The repeatability of the results generated by the DEXA apparatus (as stated in the equipment specifications) ranges for particular skeletal regions from 0,9% to 2,5% of the coefficient of variance, while the precision ranges from 3% to 5%. This means that even if we follow the strictest guidelines for test procedures, the margin of error is still several percent. We also cannot exclude the impact of errors of the three types listed above on the final results. We are convinced that the DEXA method is an excellent instrument for the diagnosis of osteoporosis (in static bone evaluation). However, its value diminishes in monitoring dynamic changes in bone tissue, even at 1-2 year intervals.

[Early results of densitometry around the cementless stem of the Parhofer-Mönch hip endoprosthesis]

Fifty-three patients with unilateral hip arthritis (31 females, 22 males) aged from 29 to 66 years (mean 52.1 years) after total hip replacement with cementless Parhofer-Mönch endoprosthesis underwent densitometry. The content (BMC) and mineral density (BMD) of calcium within proximal end of the femur was evaluated at 8-12 days postoperatively and at 6, 12 and 18 months follow-up. Early results show various mineral changes in Gruen zones around the stem. The greatest BMC and BMD decrease was found at 6 months follow-up in zones 1 and 7 as well as 2 and 6. The BMC and BMD tendency to decrease gradually ceased and slightly positive values were found in zone 3, 4 and 5 at the final evaluation.

[Ender nails in the stabilization of trochanteric fractures of the femur in the elderly]

Results of treatment for trochanteric fracture of the femur in 50 patients aged 25-91 (mean 71 years) are presented. In all cases reviewed the fracture has been stabilized with 3 or 4 Ender nails. In majority of cases bony union has been achieved. Short operating time, small incision remote from fracture site, early weight bearing constitute unquestionable advantages of the method. Most frequent complications as shortening of the extremity involved, excessive external rotation, pain related to migration of the nails, varus deformity at the fracture site were usually found in patients with marked osteoporotic changes.

[Densitometry for assessment of periacetabular bony changes after Parhofer-Mönch total hip replacement]

Densitometry for assessment of mineral changes after Parhofer-Mönch total hip replacement 10 mm around the acetabular component has been done in 53 patients (31 females and 22 males, mean age 52.1 years) with unilateral hip arthritis. Lunar DPX apparatus has been used, "manual analysis" of "Orthopedic" software and modification of DeLee and Charnley zones for DEXA technique was employed. After 6 months follow-up BMC and BMD decreased in all zones analyzed, especially in zone 2. These values increased in next 6 and 12 months but did not compensate for the primary loss.

[Use of densitometry examinations for evaluation of proximal femur fracture risk in people over 50 years of age]

The paper presents the use of dual energy X-ray absorptiometry for selecting patients with high risk of proximal femur fracture. A group of 63 patients with fracture has been compared with a group of 306 patients who fell down but did not sustain a fracture, all individuals aged over 60. Most significant bone density decrease (p < 0.001) presented as Z indices related to young population was found in all three examined areas of the proximal femur. The difference between the groups ranged between 1.62 to 2.19 SD depending on the area and the sex. Threshold values for ZYA have been established. For the femoral neck it was -1.3 SD, for Ward's triangle -1.5 SD and for trochanteric area -0.4 SD.

[Results of treating forearm bone shaft fractures with a 3.5 mm self compressive plate]

Results of 29 forearm bones shaft fracture treatment with 3.5mm self compressive plate in 26 patients aged 18-64 (mean 33) are presented. Open reduction with 3.5mm self compressive plate fixation has been performed in all cases. Anderson et al criteria were used to assess functional and radiological outcome. Excellent and good functional results were achieved in 25 cases, one was rated fair, no poor results were observed.

[Reproducibility of densitometric examinations of the tibial shaft]

The aim of this paper is to evaluate the reproducibility of tibial shaft densitometry in own method under development. It will be expressed as percentage value of coefficient of variability (%CV). Bone mineral content (BMC) and bone mineral density (BMD) were measured with a dual energy X-ray densitometer Lunar DPX; the data were analyzed with a "Orthopedic" software. Three tibial bone scans were done in 10 males. High reproducibility was found, ranging from 0.98% to 1.45% and from 1.45% to 2.08% for BMC and BMD respectively. Reproducibility increases as the analyzed surface increases. Reproducibility so high allows for further investigations; it might be interesting to monitor BMC and BMD of the tibia in course of fracture treatment by Polfix or Zespol method.

Accumulation of major organic osmolytes in rat renal inner medulla in dehydration

Osmotically active organic solutes, osmolytes, exist at high concentrations in the renal inner medulla; however, their modulation during antidiuresis remains largely undefined. Renal osmolyte levels were measured by nuclear magnetic resonance spectroscopy and biochemical assays in perchloric acid extracts from normal and dehydrated (3 days) rats. Dehydration increased urine osmolality from 1,503 to 3,748 mosmol/kg and inner medullary urea content from 2,036 to 4,405 nmol/mg protein. In addition, inner medullary trimethylamines [glycerophosphorylcholine (GPC) and betaine] and polyhydric alcohols (inositol and sorbitol) significantly increased by 95 and 78%, respectively. Ninhydrin-positive substances (amino acids), although abundant, were unchanged. Renal cortex also contained GPC, betaine, and inositol but only inositol increased with dehydration. Analysis of correlations among inner medullary osmolytes showed that only GPC was consistently elevated by dehydration and was not directly correlated with the other osmolytes. In contrast, betaine and inositol contents were linearly related to each other and both tended to rise only when sorbitol content was unchanged. In conclusion, the major osmolytes in the rat renal inner medulla can increase during antidiuresis but they are regulated in a complex manner.

Silver ion (Ag+)-induced increases in cell membrane K+ and Na+ permeability in the renal proximal tubule: reversal by thiol reagents

The initial mechanisms of injury to the proximal tubule following exposure to nephrotoxic heavy metals are not well established. We studied the immediate effects of silver (Ag+) on K+ transport and respiration with extracellular K+ and O2 electrodes in suspensions of renal cortical tubules. Addition of silver nitrate (AgNO3) to tubules suspended in bicarbonate Ringer's solution caused a rapid, dose-dependent net K+ efflux (Km = 10(-4) M, Vmax = 379 nmol K+/min/mg protein) which was not inhibited by furosemide, barium chloride, quinine, tetraethylammonium, or tolbutamide. An increase in the ouabain-sensitive oxygen consumption rate (QO2) (13.9 +/- 1.1 to 25.7 +/- 4.4 nmol O2/min/mg, P less than 0.001), was observed 19 sec after the K+ efflux induced by AgNO3 (10(-4) M), suggesting a delayed increase in Na+ entry into the cell. Ouabain-insensitive QO2, nystatin-stimulated QO2, and CCCP-uncoupled QO2 were not significantly affected, indicating preserved function of the Na+,K+-ATPase and mitochondria. External addition of the thiol reagents dithiothreitol (1 mM) and reduced glutathione (1 mM) prevented and/or immediately reversed the effects on K+ transport and QO2. We conclude that Ag+ causes early changes in the permeability of the cell membrane to K+ and then to Na+ at concentrations that do not limit Na+,K+-ATPase activity or mitochondrial function. These alterations are likely the result of a reversible interaction of Ag+ with sulfhydryl groups of cell membrane proteins and may represent initial cytotoxic effects common to other sulfhydryl-reactive heavy metals on the proximal tubule.