Selective dilution and magnetic properties of La_{0.7}Sr_{0.3}Mn_{1-x}M'_xO_3 (M' = Al, Ti)

The magnetic lattice of mixed-valence Mn ions in La$_{0.7}$Sr$_{0.3}$MnO$_3$ is selectively diluted by partial substitution of Mn by Al or Ti. The ferromagnetic transition temperature and the saturation moment decreases with substitution in both series. The volume fraction of the non-ferromagnetic phases evolves non-linearly with the substitution concentration and faster than theoretically expected. By presenting the data in terms of selective dilutions, the reduction of $T_\mathrm{c}$ is found to be scaled by the relative ionic concentrations and is consistent with a prediction derived from molecular-field theory.Comment: 6 pages, 5 figures, REVTex4.0. Submitted to PR

Fragmentation of exotic oxygen isotopes

Abrasion-ablation models and the empirical EPAX parametrization of projectile fragmentation are described. Their cross section predictions are compared to recent data of the fragmentation of secondary beams of neutron-rich, unstable 19,20,21O isotopes at beam energies near 600 MeV/nucleon as well as data for stable 17,18O beams

Short range ferromagnetism and spin glass state in Y0.7Ca0.3MnO3\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}

Dynamic magnetic properties of $\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}$ are reported. The system appears to attain local ferromagnetic order at $T_{\mathrm{SRF}} \approx 70$ K. Below this temperature the low field magnetization becomes history dependent, i.e. the zero field cooled (ZFC) and field cooled (FC) magnetization deviate from each other and closely logarithmic relaxation appears at our experimental time scales (0.3-$10^{4}$ sec). The zero field cooled magnetization has a maximum at $T_{\mathrm{f}}\approx 30$ K, whereas the field cooled magnetization continues to increase, although less sharply, also below this temperature. Surprisingly, the dynamics of the system shows non-equilibrium spin glass (SG) features not only below the maximum in the ZFC magnetization, but also in the temperature region between this maximum and $T_{\mathrm{SRF}}$. The aging and temperature cycling experiments show only quantitative differences in the dynamic behavior above and below the maximum in the ZFC-magnetization; similarly, memory effects are observed in both temperature regions. We attribute the high temperature behavior to the existence of clusters of short range ferromagnetic order below $T_{\mathrm{SRF}}$; the configuration evolves into a conventional spin glass state at temperatures below $T_{\mathrm{f}}$.Comment: REVTeX style; 8 pages, 8 figure

Unraveling Dilated Cardiomyopathy Linked to an Enigmatic MYBPC3 Variant

Background: Non-ischemic cardiomyopathy (NICM), can arise from various causes, including hemodynamic pathology, infections, immunologic abnormalities, toxic injuries, and genetic factors. Determining the prevalence of NICM is challenging due to varying definitions and diagnostic criteria, selection bias, and geographic variation. MYBPC3 is the primary gene known to cause restrictive cardiomyopathy, dilated cardiomyopathy, and left ventricular non-compaction. This gene encodes cMyBP-C, a structural protein of the heart muscle that interacts with actin, myosin, and titin to maintain sarcomeric integrity. While loss-of-function mutations are common, MYBPC3 missense variants of uncertain significance (VUS) are also prevalent. Individuals with MYBPC3 missense VUS predicted to disrupt subdomain folding (STRUM+) exhibit high incidences of adverse clinical outcomes similar to pathogenic MYBPC3 variants. Case Presentation: A 49-year-old Hispanic male with hypertension, and hyperlipidemia, who denies smoking, alcohol, or substance abuse, presented with shortness of breath and fatigue. He experienced a syncopal episode in February while on a ladder, with lightheadedness, racing heart, sharp chest pains, and difficulty swallowing, losing consciousness upon reaching the ground. The physical exam showed BP 110/65 mmHg, HR 108 bpm, RR 20 bpm, and JVD. EKG showed a left bundle branch block, and an echocardiogram revealed an ejection fraction Conclusion: Dilated cardiomyopathy can result from rare genetic mutations like VUS MYBPC3. Genetic testing is crucial for NICM patients to inform family members about the necessity of genetic testing. MYBPC3 missense VUS predicted to disrupt subdomain folding (STRUM+) presents high incidences of adverse outcomes. While MYBPC3 mutations are common in HCM, our patient presented with heart failure, possibly indicating HCM progression to heart failure or primary heart failure due to the gene mutation. GDMT and device therapy are essential in treating NICM while awaiting a heart transplant

When Two Doses Make All the Difference: The Case of Factor V Leiden in a Young Hispanic Male

Background: Recurrent venous thromboembolism (VTE) causes a substantial burden, particularly when the cause is unclear. Traditionally VTE risks include older age, immobilization, obesity, and malignancy. When VTE recurs in a young patient without these traditional factors, genetics must be considered. Of the inherited thrombophilias, Factor V Leiden (FVL) is the most common. Normally, activated factor V combines with factor X to produce thrombin, leading to clot formation. This process is regulated by activated protein C (APC), which inactivates factor V to stop coagulation. FVL is a single-base point mutation at one of the APC cleavage sites on Factor Va and results in a Factor V resistant to cleavage by APC, creating a prothrombotic state. FVL is an autosomal dominant condition, with a prevalence of 5.2% in Caucasians, 2.2% in Hispanic Americans, and 0.85% in the Mexican population. This case involves a young Hispanic male whose diagnosis was only discovered after multiple hospitalizations and interventions. Case Presentation: A 38-year-old Hispanic male presented with SOB and RLE swelling and tenderness. CTA chest was negative for PE. Venous doppler revealed multiple noncompressible thrombi in the right femoral, popliteal, and peroneal veins. Three months prior, he had been hospitalized for RLE swelling and diagnosed with deep vein thrombosis (DVT). He underwent thrombectomy due to iliofemoral extension and was treated with apixaban. After developing recurrent DVT, his cardiologist switched him to rivaroxaban, suspecting apixaban resistance, though the patient had missed two doses. He worked as a driver, but his longest trips were 2 hours maximum with frequent breaks. His brother was also recently diagnosed with DVT. Hypercoagulable workup revealed a positive single heterozygous mutation (R506Q) in the factor V gene. He was transferred to another facility for high-pressure balloon angioplasty with instructions for follow-up care from his cardiologist and hematologist. Conclusions: This case highlights a unique presentation of FVL. The patient’s only apparent risk factor was his occupation, but missing two doses of apixaban was a contributing factor to his recurrent DVT. Screening for FVL is not recommended for the general population, but in young patients with a family history of VTE, it is warranted Heterozygous FVL patients have a 1.4-fold higher lifetime risk of VTE compared to the general population. Missing even just one or two doses of a DOAC in a patient with FVL can lead to severe outcomes like hospitalization for DVT. Early screening helps guide clinical decisions, such as avoiding contraceptives in women of childbearing age and ensuring adequate DVT periprocedural prophylaxis. Additionally, this patient’s Hispanic background provides another complicating factor as thrombophilia testing is not usually pursued until after multiple expensive interventions and hospitalizations. The medical and economic burden is significant, particularly for the RGV patient population who already face multiple barriers to healthcare access compared to the general U.S. population. This case contributes to understanding thrombophilias in the Hispanic population and calls for further research into optimal long-term management for these patients

HDAC7 Is a Repressor of Myeloid Genes Whose Downregulation Is Required for Transdifferentiation of Pre-B Cells into Macrophages

B lymphopoiesis is the result of several cell-commitment, lineage-choice, and differentiation processes. Every differentiation step is characterized by the activation of a new, lineage-specific, genetic program and the extinction of the previous one. To date, the central role of specific transcription factors in positively regulating these distinct differentiation processes to acquire a B cell-specific genetic program is well established. However, the existence of specific transcriptional repressors responsible for the silencing of lineage inappropriate genes remains elusive. Here we addressed the molecular mechanism behind repression of non-lymphoid genes in B cells. We report that the histone deacetylase HDAC7 was highly expressed in pre-B cells but dramatically down-regulated during cellular lineage conversion to macrophages. Microarray analysis demonstrated that HDAC7 re-expression interfered with the acquisition of the gene transcriptional program characteristic of macrophages during cell transdifferentiation; the presence of HDAC7 blocked the induction of key genes for macrophage function, such as immune, inflammatory, and defense response, cellular response to infections, positive regulation of cytokines production, and phagocytosis. Moreover, re-introduction of HDAC7 suppressed crucial functions of macrophages, such as the ability to phagocytose bacteria and to respond to endotoxin by expressing major pro-inflammatory cytokines. To gain insight into the molecular mechanisms mediating HDAC7 repression in pre-B cells, we undertook co-immunoprecipitation and chromatin immunoprecipitation experimental approaches. We found that HDAC7 specifically interacted with the transcription factor MEF2C in pre-B cells and was recruited to MEF2 binding sites located at the promoters of genes critical for macrophage function. Thus, in B cells HDAC7 is a transcriptional repressor of undesirable genes. Our findings uncover a novel role for HDAC7 in maintaining the identity of a particular cell type by silencing lineage-inappropriate genes

Statistical Analsysis to Evaluate Heavy Metal Pollution in the Air Obatained by Moss Technique in Hanoi and its Surrounding Region

The aim of this paper was the application of statistical analysis including principal component analysis to evaluate heavy metal pollution obtained by moss technique in the air of Ha Noi and its surrounding areas and to evaluate potential pollution sources. The concentrations of 33 heavy metal elements in 27 samples of Barbula Indica moss in the investigated region collected in December of 2016 in the investigated area have been examined using multivariate statistical analysis. Five factors explaining 80% of the total variance were identified and their potential sources have been discussed