29 research outputs found
Intrinsic deviations in fluorescence yield detected x ray absorption spectroscopy the case of the transition metal L 2,3 edges
Fluorescence yield FY detected x ray absorption spectra XAS of 3d transition metal ions are calculated from the integrated 2p3d resonant x ray emission spectra. The resulting FY XAS spectra are compared with the normal XAS spectra corresponding to the absorption cross section and significant deviations between the two spectra are found. This implies that the assumption that the FY XAS spectrum identifies with the XAS spectrum is disproved. Especially for the early transition metal systems the differences between the FY XAS and XAS are large, due to the opening of inelastic decay channels from selected x ray absorption final states. The theoretical calculations show that the difference between FY detection and XAS is largest for the detection in depolarized geometry. The calculations are compared with experimental spectra for oxides and coordination compounds for Fe2C, Co2C and Ni2C systems. The implications for the sum rules in XAS and magnetic circular dichroism experiments are discusse
Precision medicine for mood disorders: objective assessment, risk prediction, pharmacogenomics, and repurposed drugs
Mood disorders (depression, bipolar disorders) are prevalent and disabling. They are also highly co-morbid with other psychiatric disorders. Currently there are no objective measures, such as blood tests, used in clinical practice, and available treatments do not work in everybody. The development of blood tests, as well as matching of patients with existing and new treatments, in a precise, personalized and preventive fashion, would make a significant difference at an individual and societal level. Early pilot studies by us to discover blood biomarkers for mood state were promising [1], and validated by others [2]. Recent work by us has identified blood gene expression biomarkers that track suicidality, a tragic behavioral outcome of mood disorders, using powerful longitudinal within-subject designs, validated them in suicide completers, and tested them in independent cohorts for ability to assess state (suicidal ideation), and ability to predict trait (future hospitalizations for suicidality) [3-6]. These studies showed good reproducibility with subsequent independent genetic studies [7]. More recently, we have conducted such studies also for pain [8], for stress disorders [9], and for memory/Alzheimer's Disease [10]. We endeavored to use a similar comprehensive approach to identify more definitive biomarkers for mood disorders, that are transdiagnostic, by studying mood in psychiatric disorders patients. First, we used a longitudinal within-subject design and whole-genome gene expression approach to discover biomarkers which track mood state in subjects who had diametric changes in mood state from low to high, from visit to visit, as measured by a simple visual analog scale that we had previously developed (SMS-7). Second, we prioritized these biomarkers using a convergent functional genomics (CFG) approach encompassing in a comprehensive fashion prior published evidence in the field. Third, we validated the biomarkers in an independent cohort of subjects with clinically severe depression (as measured by Hamilton Depression Scale, (HAMD)) and with clinically severe mania (as measured by the Young Mania Rating Scale (YMRS)). Adding the scores from the first three steps into an overall convergent functional evidence (CFE) score, we ended up with 26 top candidate blood gene expression biomarkers that had a CFE score as good as or better than SLC6A4, an empirical finding which we used as a de facto positive control and cutoff. Notably, there was among them an enrichment in genes involved in circadian mechanisms. We further analyzed the biological pathways and networks for the top candidate biomarkers, showing that circadian, neurotrophic, and cell differentiation functions are involved, along with serotonergic and glutamatergic signaling, supporting a view of mood as reflecting energy, activity and growth. Fourth, we tested in independent cohorts of psychiatric patients the ability of each of these 26 top candidate biomarkers to assess state (mood (SMS-7), depression (HAMD), mania (YMRS)), and to predict clinical course (future hospitalizations for depression, future hospitalizations for mania). We conducted our analyses across all patients, as well as personalized by gender and diagnosis, showing increased accuracy with the personalized approach, particularly in women. Again, using SLC6A4 as the cutoff, twelve top biomarkers had the strongest overall evidence for tracking and predicting depression after all four steps: NRG1, DOCK10, GLS, PRPS1, TMEM161B, GLO1, FANCF, HNRNPDL, CD47, OLFM1, SMAD7, and SLC6A4. Of them, six had the strongest overall evidence for tracking and predicting both depression and mania, hence bipolar mood disorders. There were also two biomarkers (RLP3 and SLC6A4) with the strongest overall evidence for mania. These panels of biomarkers have practical implications for distinguishing between depression and bipolar disorder. Next, we evaluated the evidence for our top biomarkers being targets of existing psychiatric drugs, which permits matching patients to medications in a targeted fashion, and the measuring of response to treatment. We also used the biomarker signatures to bioinformatically identify new/repurposed candidate drugs. Top drugs of interest as potential new antidepressants were pindolol, ciprofibrate, pioglitazone and adiphenine, as well as the natural compounds asiaticoside and chlorogenic acid. The last 3 had also been identified by our previous suicidality studies. Finally, we provide an example of how a report to doctors would look for a patient with depression, based on the panel of top biomarkers (12 for depression and bipolar, one for mania), with an objective depression score, risk for future depression, and risk for bipolar switching, as well as personalized lists of targeted prioritized existing psychiatric medications and new potential medications. Overall, our studies provide objective assessments, targeted therapeutics, and monitoring of response to treatment, that enable precision medicine for mood disorders
A case-only study to identify genetic modifiers of breast cancer risk for BRCA1/BRCA2 mutation carriers
Breast cancer (BC) risk for BRCA1 and BRCA2 mutation carriers varies by genetic and familial factors. About 50 common variants have been shown to modify BC risk for mutation carriers. All but three, were identified in general population studies. Other mutation carrier-specific susceptibility variants may exist but studies of mutation carriers have so far been underpowered. We conduct a novel case-only genome-wide association study comparing genotype frequencies between 60,212 general population BC cases and 13,007 cases with BRCA1 or BRCA2 mutations. We identify robust novel associations for 2 variants with BC for BRCA1 and 3 for BRCA2 mutation carriers, P < 10−8, at 5 loci, which are not associated with risk in the general population. They include rs60882887 at 11p11.2 where MADD, SP11 and EIF1, genes previously implicated in BC biology, are predicted as potential targets. These findings will contribute towards customising BC polygenic risk scores for BRCA1 and BRCA2 mutation carriers
Performance enhancement of DS/CDMA system using chaotic complex spreading sequence
10.1109/TWC.2005.847028IEEE Transactions on Wireless Communications43984-98
A novel DS/SS system with complex chaotic spreading sequence
IEEE Vehicular Technology Conference5732090-2094IVTC
Paleoproductivity shifts since the last 130 ka off Lakshadweep, Southeastern Arabian Sea
Marine sediment deposited on the ocean floor and near coastal areas, the western coastal regions of India provide records of monsoonal shifts and productivity. To understand the paleoproductivity in the northern Indian Ocean, we analyzed carbon, hydrogen, nitrogen, sulfur, total organic carbon (TOC) and calcium carbonate (CaCO3) in a deep-sea sediment core collected using gravity corer (GC-01) off Lakshadweep, Southeastern Arabian Sea. The results were then compared with the previous data generated from the surrounding area sediment cores to understand the productivity variations since the last 130 ka. The CaCO3 content in the sediment core varies from 40.82% to 62.48% (with a mean value of 51.96%) and it is noted that these values were lower during the glacial episodes (Marine Isotope Stages-2 and 4) than the interglacial episodes (MIS-1, 3 and 5). The C/N ratio varied from 0.14 to 34.25, but was less than 9, since ∼74 ka to recent, suggesting a marine origin for the organic carbon. The C/N ratio fluctuated significantly during MIS-5, and relatively the highest C/N ratio was observed at 5e ∼127, 5d ∼110 and 5b ∼85 ka, corresponding to stadials 5b and 5d, (except 5e) indicating terrestrial OC from C3 plants. The low C/N ratios during ∼128, ∼102, ∼76 and ∼32 ka match with the interstadials especially during MIS 5 (5a, 5c and 5e), correspondingly, and are marine OC in the source. This suggests that the MIS-5 stadial was interrupted via land source signifying higher productivity owing to the strong southwest monsoon during these periods. Further, high productivity was also observed during the Last Glacial Maximum (LGM) and Holocene in the Southeastern Arabian Sea since the 130 ka.Ministry of Earth Science (MoES), Govt. of India with reference number MoES/16/07/11(i)-RDEAS and MoES/P.O.(Seismic)8(09)-Geochron/201
Method to eliminate the limit cycle oscillation for digitally controlled DC–DC converter using reduced state Kalman filter
Surgical outcomes and strategy of hypertrophic obstructive cardiomyopathy
Objective: To evaluate the surgical clinical results of hypertrophic obstructive cardiomyopathy. Methods: We retrospectively collected data on 24 patients who underwent surgical management in the past ten years in two hospitals in China and Madras Medical Mission in India. Myomectomy was carried out on all patients. Among them 3 patients underwent mitral valve replacement; 2 patients underwent mitral valve repair (anterior mitral leaflet plication); 2 patients underwent aortic valve replacement; 1 patient underwent aortic valve repair; 2 patients underwent aortic root replacement; 1 patient underwent Bentall’s procedure and 1 patient underwent coronary artery bypass grafting because of a breached muscle bridge. Results: One patient died of post-operative heart failure. The mean follow-up time was 4.3 years. There was significant improvement in the symptomatic status. Sixteen patients were asymptomatic with good effort tolerance and only four patients had New York heart association (NYHA) Classes I~II due to associated valvular lesions. Conclusion: Our experience proved that symptomatic hypertrophic obstructive cardiomyopathy or non-symptomatic hypertrophic obstructive cardiomyopathy with combined heart disease is indication for surgery as surgical intervention could get better clinical results in this kind of patients compared with other non-surgical method because it beneficially reduces the systolic anterior motion (SAM) of the mitral valve leaflet, which could not be avoided by other non-surgical treatment
The phenotypic continuum of ATPLA3-related disorders
Background and objectives: ATP1A3 is associated with a broad spectrum of predominantly neurological disorders, that continues to expand beyond the initially defined phenotypes of Alternating Hemiplegia of Childhood (AHC), Rapid-onset Dystonia Parkinsonism (RDP) and Cerebellar ataxia, Areflexia, Pes cavus, Optic atrophy, Sensorineural hearing loss syndrome (CAPOS). This phenotypic variability makes it challenging to assess pathogenicity of an ATP1A3 variant found in an undiagnosed patient. We describe the phenotypic features of individuals carrying a pathogenic/likely pathogenic ATP1A3 variant and perform a literature review of all ATP1A3 variants published thus far in association with human neurological disease. Our aim is to demonstrate the heterogeneous clinical spectrum of the gene and look for phenotypic overlap between patients that will streamline the diagnostic process.
Methods: Undiagnosed individuals with ATP1A3 variants were identified within the cohort of the Deciphering Developmental Disorders (DDD) study with additional cases contributed by collaborators internationally. Detailed clinical data was collected with consent through a questionnaire completed by the referring clinicians. PubMed was searched for publications containing the term “ATP1A3” from 2004 to 2021.
Results: Twenty-four individuals with a previously undiagnosed neurological phenotype were found to carry 21 ATP1A3 variants. Eight variants have been previously published. Patients experienced on average 2-3 different types of paroxysmal events. Permanent neurological features were common including microcephaly (7;29%), ataxia (13;54%), dystonia (10;42%) and hypotonia (7;29%). All patients had cognitive impairment. Neuropsychiatric diagnoses were reported in 16 (66.6%) individuals. Phenotypes were extremely varied and most individuals did not fit clinical criteria for previously published phenotypes.
On review of the literature, 1108 individuals have been reported carrying 168 different ATP1A3 variants. The most common variants are associated with well-defined phenotypes, while more rare variants often result in very rare symptom correlations, such as are seen in our study.
CADD scores of pathogenic and likely pathogenic variants were significantly higher and variants clustered within six regions of constraint.
Conclusion: Our study shows that looking for a combination of paroxysmal events, hyperkinesia, neuropsychiatric symptoms, and cognitive impairment, as well as evaluating CADD score and variant location can help identify an ATP1A3-related condition, rather than applying diagnostic criteria alone