Type Of Beta Research Articles

Can we use heavy nuclei to detect relic neutrinos?

Recent analysis of the viability of solid state-based relic neutrino detectors has revealed the fundamental necessity for the use of heavy, A>100, beta -decayers as neutrino targets. Of all heavy isotopes, and stand out for their sufficiently low decay energies, reasonable half-life times and stable daughter nuclei. However, the crucial bit of information, that is the soft neutrino capture cross-section is missing for both isotopes. The main reason for that is a particular type of beta -decay, which precludes a simple link between the isotope’s half-life time and the neutrino capture rate. In light of the necessity for a reliable estimate of the capture rate – unimpeded by potentially devastating theoretical uncertainties – prior to using the isotope in a full-scale experiment, we propose an experimental method to bypass this difficulty and obtain the capture cross-section of a soft neutrino by a given isotope from the isotope’s beta -spectrum.

Clinical significance of mutational variants in beta and alpha genes in patients with hemoglobinopathies from two large Greek centers: a complex interplay between genotype and phenotype.

Hemoglobinopathies affect patients in the wider Mediterranean area consisting of 4 distinct subgroups: beta thalassemia major (TM), beta thalassemia intermedia (TI), sickle cell disease (SCD) and hemoglobin H disease (alpha thalassemia). The clinical spectrum varies from mild to severe. Complex interactions between genes and environmental factors form the clinical manifestations. There is an unmet need to clarify these multifactorial mechanisms.This is the first Greek study describing mutational alleles (HBB and HBA1/HBA2 gene variants) in 217 patients with hemoglobinopathies of two large centers in Greece (Larissa and Athens) and associating particular genotypes or gene variants with clinical manifestations (transfusion frequency, complications). Thus, the complex interplay between corresponding genotypes and phenotypes was investigated.Our results are in accordance with previous national studies with limited variations, due to regional prevalence of specific gene variants, as expected. It is also a description of the prevalence of hemoglobinopathies in the Greek population. The type and prevalence of beta and alpha globin gene variants differ significantly among countries. We also confirm the well-known observation of many studies that in our beta thalassemic or SCD patients, co-inheritance of variants in the alpha globin genes, leading to absence or reduction of alpha globin synthesis were associated with milder clinical course, whereas the inheritance of additional alpha genes (triplication) led to a more severe clinical phenotype.In cases in whom the genotype and phenotype did not correlate, factors like the function or modification of possible regulatory genes or additional nutritional-environmental effects should be investigated. KEY MESSAGES: • This is the first Greek study, fully molecularly defining the beta and alpha mutational alleles in 217 patients with hemoglobinopathies of two large centers in Greece and correlating particular genotypes or gene variants with clinical manifestations (transfusion frequency, complications). • In the beta thalassemic or SCD patients of our cohort, co-inheritance of variants in the alpha globin genes, leading to absence or reduction of alpha globin synthesis were associated with milder clinical course (confirmation of a well-known previous observation). • The inheritance of additional alpha genes (triplication) led to a more severe clinical phenotype (confirmation of a well known previous observation). • The function or modification of possible regulatory genes should be investigated in cases in whom the genotype and phenotype did not correlate.

Visual Outcomes in Pediatric Patients with Peters Anomaly.

PurposeThis study aimed to evaluate the visual outcomes of pediatric patients diagnosed with Peters anomaly (PA) in a tertiary eye care center.MethodsThis was a retrospective study undertaken at a single academic center. Clinical records of pediatric patients diagnosed with PA from 2000 to 2017 were reviewed. Parameters recorded included visual acuity (VA), intraocular pressure (IOP), presence of glaucoma, and surgical procedures performed. The impact of PA type on final visual acuity levels was analyzed using generalized estimation equation models.ResultsTwenty-one eyes from 11 patients were analyzed. At the final visit, 9 eyes (42.8%) had a VA ≥20/200, while 12 (57%) had <20/200, ranging from 20/250 to no light perception. Of the study cohort, 15 (71.5%) eyes had type I, while six (28.5%) had type II PA. Glaucoma was present in 20 eyes (95%) at the final visit. One eye had dense central leucoma and microphthalmos where IOP could not be measured accurately. Seventeen eyes (81%) underwent at least one intraocular surgery, while the average number of surgeries per eye was 2.9 ± 2.5 (range=0– 9). The type of PA beta(se)=0.53 (0.41), p = 0.20] was not found to be a significant risk factor for worse VA.ConclusionSevere visual impairment develops in the majority of patients with PA. The type of anomaly does not appear to be associated with a worse visual function in patients with PA. Glaucoma develops in a high percentage of this patient population, and thus close monitoring of IOP in this patient population is crucial.

A multi-channel beta–gamma coincidence counting system using well-HPGe and plastic scintillation detectors for radioactive Xenon measurements

Abstract A new type of multi-channel beta–gammacoincidence counting system was developed for the analysis of radioactive Xenon samples with low-level radioactivity . The proposed system consists of a state-of-the-art well-HPGe detector with a large well volume ( ∅ 28 mm × 40 mm) and a cylindrical plastic scintillation detector with an interior volume of 8.8 cm3. A two-dimensional beta–gamma coincidence histogram was obtained, and the beta–gamma coincidence counting efficiency was estimated using gaseous radioxenons and Monte Carlo simulation with the MCNP code. The energy resolution of the plastic scintillation detector for the 129.4 keV internal conversion electron was 29%, and the minimum detectable concentration for 131m Xe, 133Xe, 133m Xe, and 135Xe was calculated as 0.27 mBq/m3, 0.23 mBq/m3, 0.16 mBq/m3 and 0.24 mBq/m3 under the assumed conditions of a 20000 s measurement and a 10 m3 air sample with the beta–gamma​ coincidence mode, respectively.

Price delay and post-earnings announcement drift anomalies: The role of option-implied betas

In this study, we used informational advantage in the options market to investigate whether the option-implied equity risk developed by Chen, Chung, and Tsai (2016) - viewed as a type of time-varying beta - can help explain both the Hou and Moskowitz (2005) price delay premium and post-earnings announcement drift (PEAD). Our empirical results revealed a clear association between quintile portfolios with greater price delay premiums and higher option-implied betas, while the Fama-MacBeth regressions showed that the implied betas are positively related to future delay-based portfolio returns. Regarding the PEAD, we discerned a general increase in the mean of portfolio option-implied betas with standardized unexpected earnings portfolio drift. Our regression results support the notion that a portfolio’s PEAD can be viewed as compensation for the variations in option-implied betas.

Reasons of Unknown HPLC Peaks during Hemoglobin Analysis for Patients with Beta Thalassemias

Reasons of Unknown HPLC Peaks during Hemoglobin Analysis for Patients with Beta Thalassemias

Lenalidomide in multiple myeloma: an evidence-based review of its role in therapy.

Multiple myeloma (MM) is a relatively common and incurable hematological malignancy. Currently, there is no single standard therapy, with choice of treatment dependent on individual patient factors. Lenalidomide is an immunomodulatory drug with potent antitumor, antiangiogenic, immunomodulatory, and proapoptotic activity in MM. To evaluate the evidence for the use of lenalidomide in its current indication in relapsed or refractory MM, and additionally its investigational use for the treatment of newly diagnosed MM. In patients with relapsed and refractory MM, adding lenalidomide to high-dose dexamethasone significantly improves response rates and time-to-progression, relative to high-dose dexamethasone alone. This translates into a significant extension of overall survival (with a median extension of 9.1 months in a pivotal phase III study). Outcome is independent of patient age, number of previous therapies, type of previous therapy (including thalidomide or autologous stem cell transplantation), renal impairment, and beta(2)-microglobulin level. Evidence suggests that combining lenalidomide with low-dose dexamethasone improves outcomes in patients with newly diagnosed disease and is superior to lenalidomide combined with high-dose dexamethasone. Myelosuppression is the predominant toxicity observed, although some studies have shown high incidences of venous thromboembolism in the absence of prophylactic antithrombotic anticoagulation therapy. There is currently only limited evidence regarding the health economics of lenalidomide. ROLE IN THERAPY: The encouraging results obtained with lenalidomide alone and in combination with dexamethasone in patients with relapsed or refractory MM have led to its adoption as a recommended therapy in patients who have received at least one prior treatment. Emerging evidence supports the ongoing investigation of lenalidomide in combination with low-dose dexamethasone, and in other combinations including bortezomib, for use both in relapsed, refractory, and newly diagnosed MM.

Zeolite beta synthesized with acid-treated metakaolin and its application in diesel hydrodesulfurization

A new type of zeolite beta (denoted as MB) with multi-pore system was synthesized by using in situ synthesized method from kaolin mineral in this study. NiW/Al 2O 3–MB and NiW/TiO 2–Al 2O 3–MB catalysts were prepared and the hydrodesulfurization (HDS) activities of these catalysts were evaluated with FCC diesel feed. The samples were characterized by N 2 physisorption, XRD, SEM, TPR, FT-IR spectroscopy of pyridine adsorption, HRTEM and XPS techniques. The HDS results showed that the MB-containing catalyst exhibited much higher HDS conversion (98.7%) than that of NiW/γ-Al 2O 3 (97.5%). The incorporation of TiO 2 into the composite supports further increased the HDS conversion (99.3%) of NiW/TiO 2–Al 2O 3–MB. The higher HDS activity was mainly associated with the appropriate ratio of B/L (Brönsted acid/Lewis acid) and the enhanced hydrogenation activity.

Surface plasmon resonance and biosensor technology for real-time molecular diagnosis of beta o 39 thalassemia mutation.

Biospecific interaction analysis (BIA) employing surface plasmon resonance (SPR) and biosensor technologies is of interest in clinical genetics. However, few data are available on its use in hereditary diseases caused by genetic mutations. The primary aim of this study was the refinement of BIA technology for use in identifying the beta o 39 mutation of the beta-globin gene, a mutation which causes a common type of beta o thalassemia. Target-biotinylated PCR products were immobilized on streptavidin-coated sensor chips and diagnosed using SPR-based BIA performed by injecting specific oligonucleotide probes into the sensor chip. We demonstrated that the beta o 39 mutation can be easily and reproducibly identified during the association phase. This should be considered a pilot study demonstrating the ability of SPR-based BIA to detect point mutations in the beta-globin gene by real-time monitoring of hybridization between oligonucleotide probes and target-biotinylated PCR products generated from genomic DNA from normal, heterozygous individuals and homozygous beta o thalassemia patients.

Electron Transfer Kinetics between Hemoglobin Subunits

The kinetics for electron transfer have been measured for samples of hemoglobin valency hybrids with initially one type of subunit, alpha or beta, in the oxidized state. Incubation of these samples under anaerobic conditions tends to randomize the type of subunit that is oxidized. With a time coefficient of a few hours at pH 7, 25 degrees C, the Hb solution (0.1 mm heme) approaches a form with about 60% of beta chains reduced, indicating a faster transfer rate in the direction alpha to beta. There was no observable electron transfer for samples saturated with oxygen. The electron transfer occurs predominantly between deoxy and aquo-met subunits, both high spin species. Furthermore, electron transfer does not depend on the quaternary state of hemoglobin. Incubation of oxidized cross-linked tetramer Hb A with deoxy Hb S also displayed electron transfer, implying a mechanism via inter-tetramer collisions. A dependence on the overall Hb concentration confirms this mechanism, although a small contribution of transfer between subunits of the same tetramer cannot be ruled out. These results suggest that in vivo collisions between the Hb tetramers will be involved in the relative distribution of the methemoglobin between subunits in association with the reductase system present in the erythrocyte.

Is Beta Dead or Alive?

The debate about whether beta is dead or alive has heated up once again. We believe the empirical work supporting either side of the argument is limited because market frictions are not adequately addressed. This study clarifies the controversy about the issue by creating a new moving‐average beta and analyzing two market anomalies: the turn‐of‐the‐year and the Monday effects. What is discovered in this research is (1) that a fundamental source of the problem underlying the two types of market anomalies is the persistence of market frictions that retard the arbitrage process; (2) that beta is seriously ill if the effects of market frictions are ignored; and (3) that beta is alive and well if the effects of market frictions are accommodated. Also, we show, by using an optimal lead/lag structure, the moving‐average beta provides significantly higher explanatory power for the turn‐of the‐year and the Monday effects than betas created from ordinary least squares regression and Scholes‐Williams and Fama‐French methods because the moving‐average beta accommodates the effects of market frictions into the body of beta itself. This new type of beta, a moving‐average beta, is demonstrated to be robust.

Beta–Adrenergic Antagonists in the Prevention of Gastrointestinal Rebleeding in Patients With Cirrhosis: A Meta–Analysis

A meta–analysis of 12 selected randomized trials was performed to assess the efficacy of beta–blockers in the prevention of rebleeding and the effect on long–term survival in patients with cirrhosis. Five end points were assessed: rebleeding, variceal rebleeding, death, death from bleeding, and adverse events. Analyses were performed according to the intention–to–treat method. For each end point, heterogeneity and treatment efficacy were assessed by the Der Simonian and Peto methods. When a significant difference was observed, sensitivity analyses were performed by successive stratifications according to treatment duration, cause of initial bleeding, use of placebo, type of beta–blocker, type of publication, certainty of randomization, severity of cirrhosis, interval between index bleed and randomization, and methodological quality. Beta–blockers significantly increased the mean percentage of patients free of rebleeding (21% mean improvement rate, CI 95%: 10%–32%, P &lt; .001, relative risk 1.42), the mean percentage of patients free of variceal rebleeding (20% mean improvement rate, CI 95%: 11%–28%, P &lt; .001), the mean survival rate (5.4% mean improvement rate, CI 95%: 0%–11%, P = .05, relative risk 1.27), the mean percentage of patients free of bleeding death (7.4%, CI 95%: 2%–13%, P &lt; .01, relative risk 1.50). Five patients would need to be treated with beta–blockers to prevent one rebleeding episode, 14 treated to prevent one death, and 13 treated to prevent one death from bleeding. There was no significant heterogeneity among studies by both methods of analysis. In patients with esophageal varices, beta–blockers significantly increase the mean percentage of patients free of rebleeding and the mean survival rate at 2 years.

Structure-function analysis of the mammalian DNA polymerase .beta. active site: role of aspartic acid 256, arginine 254, and arginine 258 in nucleotidyl transfer

The crystal structure of the catalytic domain of rat DNA polymerase beta revealed that Asp256 is located in proximity to the previously identified active site residues Asp190 and Asp192. We have prepared and kinetically characterized the nucleotidyl transfer activity of wild type and several mutant forms of human and rat pol beta. Herein we report steady-state kinetic determinations of KmdTTP, Km(dT)16, and kcat for mutants in residue Asp256 and two neighboring residues, Arg254 and Arg258, all centrally located on strand beta 7 in the pol beta structure. Mutation of Asp256 to alanine abolished the enzymatic activity of pol beta. Conservative replacement with glutamic acid (D256E) led to a 320-fold reduction of kcat compared to wild type. Replacement of Arg254 with an alanine (R254A) resulted in a 50-fold reduction of kcat compared to wild type. The Km(dT)16 of D256E and R254A increased about 18-fold relative to wild type. Replacement of Arg254 with a lysine resulted in a 15-fold decrease in kcat, and a 5-fold increase in the Km(dT)16. These kinetic observations support a role of Asp256 and Arg254 in the positioning of divalent metal ions and substrates in precise geometrical orientation for efficient catalysis. The mutation of Arg258 to alanine (R258A) resulted in a 10-fold increase in KmdTTP and a 65-fold increase in Km(dT)16 but resulted in no change of kcat. These observations are discussed in the context of the three-dimensional structures of the catalytic domain of pol beta and the ternary complex of pol beta, ddCTP, and DNA.

Transforming growth factor beta induces a beta-responsive calcium fluxes in neurons.

The beta-amyloid (a beta) peptide is a neurotoxic peptide that accumulates in the brains of Alzheimer patients, but is also present in body fluids at subnanomolar levels. The potential effects of these low levels of a beta are unclear. We have recently shown that physiologic levels of a beta increase tyrosine phosphorylation and induce increases in cytosolic calcium. The basement membrane mixture, Matrigel, is required for observation of the a beta-induced calcium response. We now show that transforming growth factor beta (TGF beta) is the active component in Matrigel eliciting the a beta/calcium response. The response to the type of TGF beta varies depending on the cell type with TGF beta 1 eliciting a beta responsiveness in olfactory neuroblasts, and TGF beta 2 eliciting a beta responsiveness in PC12 cells.

Cloning and expression of cDNA for a new type of Gal beta 1,3GalNAc alpha 2,3-sialyltransferase

Based on the sequences of the highly conserved segments in the previously cloned sialyltransferases, a cDNA encoding a new type of Gal beta 1,3GalNAc alpha 2,3-sialyltransferase (ST3GalA.2) has been isolated from both mouse and rat brain cDNA libraries. The cDNA sequences included an open reading frame coding for 350 amino acids, and the primary structure of this enzyme suggested a putative domain structure consisting of four regions, like that in other glycosyltransferases. The deduced amino acid sequence of ST3GalA.2 (mouse) showed 76% identity in the active domain with that of the previously cloned mouse Gal beta 1,3GalNAc alpha 2,3-sialyltransferase (ST3GalA.1 (Lee, Y.-C., Kurosawa, N., Hamamoto, T., Nakaoka, T., and Tsuji, S. (1993) Eur. J. Biochem. 216, 377-385)). Northern blotting indicated that the expression of ST3GalA.2 mRNA is tissue-specific, it being prominent in brain and liver, while that in the other tissues is very low. This enzyme expressed in COS-7 cells exhibited transferase activity only toward the disaccharide moiety of Gal beta 1,3GalNAc of glycolipids as well as glycoproteins and oligosaccharides like ST3GalA.1, but showed a difference in acceptor substrate preference, i.e. asialo-GM1 and GM1 were much more suitable substrates for ST3GalA.2 than for ST3GalA.1.

β-Thalassemia Intermedia in Two Turkish Families is Caused by the Interaction of HB Knossos [β27(B9)ALA→SER] and of HB City of hope [β69(E13)Gly→Ser] with B°-Thalassemia

We have studied a few members of two Turkish families, who had a beta-thalassemia of the intermediate type. An abnormal hemoglobin was found in both families, which when present in association with beta(0)-thalassemia was considered to be the primary cause for the increased severity of the disease. In the first family this variant was Hb Knossos [beta 27(B9)Ala----Ser] which occurred together with the frameshift in codon #8 type of beta(0)-thalassemia. This compound heterozygosity, observed for the first time in the Turkish population was characterized by a considerable increase in Hb F production, mainly of the G gamma type, as expected for a chromosome with haplotype IV. In the second family, the variant was Hb City of Hope [beta 69(E13)Gly----Ser] which was present in combination with an unknown type of beta-thalassemia. The increase in Hb F production in the compound heterozygote was minimal. Reversed phase high performance liquid chromatography and the DNA amplification-synthetic oligonucleotide probe procedure were major tools in identifying the different abnormalities.

DNA polymorphisms in North Sardinian newborns and their linkage with abnormal gamma globin gene arrangements and with beta (0) -thalassemia.

Fetal hemoglobin analysis and globin gene mapping have identified one type of beta(0)-thalassemia and four different gamma globin gene arrangements among newborn babies from the northern part of Sardinia. The beta(0)-thalassemia with a nonsense mutation at codon 39 was found on two chromosomes, each with a distinct pattern of polymorphic restriction sites; one had the A gamma T (A gamma 75 Ile----Thr) mutation, while the second did not. Four closely related haplotypes were identified for chromosomes with the A gamma T mutation. The gamma-thalassemia heterozygosity with the -GA gamma- hybrid gene fell into two categories. One apparently originated through crossing-over between mismatched chromosomes characterized by the most common haplotype, while the other had polymorphisms resembling those of a less frequently occurring chromosome. Chromosomes with the -G gamma-AG gamma-A gamma- triplication had polymorphic sites to be expected for this condition, being complimentary to the -GA gamma- thalassemias. Of the two additional gamma globin gene variations the -G gamma- G gamma- arrangement was associated with the chromosome with the most commonly occurring haplotype, while the chromosome with the -A gamma-A gamma- arrangement had a haplotype characteristic for that with the A gamma T mutation, which identified an -A gamma-A gamma T- arrangement. The incidental discovery of a silent beta-chain mutant, Hb Hamilton, with the Val----Ile substitution at position beta 11, in five newborns was also reported.

Sickle cell anaemia among Eti-Turks: haematological, clinical and genetic observations.

Haematological and genetic observations have been made on 71 SS Eti-Turk patients and their relatives from Cukurova (southern Turkey) and of immigrant families in The Netherlands. Similar data were collected for 25 Black patients and their relatives from Surinam, Netherlands Antilles, and Kenya. Haematological and clinical results were the same for both groups; the haemolytic anaemia in the Turkish patients was as severe as in the others. Haplotyping, involving nine restriction sites, identified haplotype 19 (Antonarakis et al, 1984) as the major type among the Eti-Turks; this chromosome has previously primarily been observed among SS patients from West Africa. The suggestion that the beta S-chromosome among Eti-Turks originates from that area is supported by a relatively high incidence of alpha-thalassaemia-2 (the 3.7 kb deletion), also frequently present in the Black population of West Africa, and by the absence of other major haplotypes, such as types 20 and 3, characteristic for the beta S-chromosome in the population of Central Africa and Kenya, and in Senegal, respectively. The Saudi Arabian type of beta S chromosome in association with the haplotype 19 beta S chromosome was present in only one Eti-Turk patient; this 30-year-old female was mildly affected and exhibited a high level of fetal haemoglobin.

Ferrara beta 0 thalassaemia caused by the beta 39 nonsense mutation.

Ferrara type of beta 0 thalassaemia has two unusual features: first, normal beta-globin chain synthesis is inducible either in cell-free systems prepared from patients' reticulocytes by adding supernatant factors from non-thalassaemic reticulocyte lysates or in heterologous cell-free translation of thalassaemic mRNA; second, beta-globin synthesis is inducible in patients in vivo after blood transfusion. We now describe a molecular lesion of the beta-globin gene that is common to nine cases of Ferrara beta 0 thalassaemia but cannot be reconciled with the inducible response.

The haemoglobin pattern of sickle cell and haemoglobin C beta +-thalassaemia in Liberia.

Haemoglobin components in 21 Liberians with Hb S beta +-thalassaemia and four with Hb C beta +-thalassaemia were measured to classify the forms of beta +-thalassaemia present in the population. In 20 Hb S and all Hb C beta +-thalassaemics the data were consistent with the interaction of these variants with the mild type 2 (Negro) form of beta +-thalassaemia. The data available were insufficient to classify the remaining case, a young child. It was concluded that the clinically more severe type of beta +-thalassaemia giving Hb A levels of 5 to 15% in compound heterozygotes is probably uncommon in Liberia.