Biomedical Applications of Raman Spectroscopy Lawson, E. E.; Barry, B. W.; Williams, A. C. ...
Journal of Raman spectroscopy,
February 1997, Letnik:
28, Številka:
2-3
Journal Article
In a previous study of rachitic children in Jos, Nigeria we concluded that inadequate dietary intake of calcium was the primary contributing factor to the development of their rickets. The objective ...of the present study was to determine the effect of calcium supplementation in 10 children with radiographically and biochemically proven rickets from the same geographical area. Rachitic children were provided with calcium supplements of 1000 mg/day for a period of 3 months. Serum and urine samples were obtained at baseline and at 24 hours, 1 week, 4 weeks, and 12 weeks after initiation of supplementation. Serum calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were measured at each time point. Dietary recalls obtained at two separate times were used to estimate usual daily intakes of calcium and phosphorus. Ten non-rachitic age-matched controls from the same geographical area were recruited for comparison. Nine of 10 rachitic subjects had radiographic evidence of healing after 3 months of calcium therapy. Although serum calcium concentrations returned to control levels, other biochemical data indicated that the rickets of these subjects may have been multifactorial in aetiology, pointing to a possible defect in the synthesis of 25-hydroxyvitamin D.
To investigate possible causes of the variable response to treatment in pediatric B-precursor acute lymphoblastic leukemia (ALL) and to establish potential novel therapeutic targets, we used ionizing ...radiation (IR) exposure as a model of DNA damage formation to identify tumors with resistance to p53-dependent apoptosis. Twenty-one of 40 ALL tumors responded normally to IR, exhibiting accumulation of p53 and p21 proteins and cleavage of caspases 3, 7, and 9 and of PARP1. Nineteen tumors exhibited apoptotic resistance and lacked PARP1 and caspase cleavage; although 15 of these tumors had normal accumulation of p53 and p21 proteins, examples exhibited abnormal expression of TRAF5, TRAF6, and cIAP1 after IR, suggesting increased NF-κB prosurvival signaling as the mechanism of apoptotic resistance. The presence of a hyperactivePARP1mutation in one tumor was consistent with such increased NF-κB activity. PARP1 inhibition restored p53-dependent apoptosis after IR in these leukemias by reducing NF-κB DNA binding and transcriptional activity. In the remaining 4 ALL tumors, apoptotic resistance was associated with aTP53mutation or with defective activation of p53. We conclude that increased NF-κB prosurvival signaling is a frequent mechanism by which B-precursor ALL tumors develop apoptotic resistance to IR and that PARP1 inhibition may improve the DNA damage response of these leukemias.
A growing body of scientific evidence over the last two decades suggests that certain ethnic groups may require lower dosages of standard antipsychotics for the treatment of schizophrenia symptoms. ...Recent studies have implicated the role of genetic and environmental factors in the metabolism of these drugs as the basis for this differential response. In this pilot study, 10 Hispanic and 8 non-Hispanic patients with schizophrenia were enrolled in a double-blind, parallel-group, inpatient risperidone dosing (daily versus twice daily) trial with the novel antipsychotic risperidone. The result of repeated measures ANOVA reveals a significant interaction effect for race, indicative of a faster rate of symptom improvement (PANSS General) in Hispanic patients. The findings suggest that this novel agent may be preferable for certain ethnic groups. A trend toward more frequently occurring extrapyramidal symptoms among Hispanics was also found, which suggests that dosages lower than those typically recommended may be necessary in Hispanic schizophrenics.
We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data from the energetic electron detector on the Electron Losses and ...Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at 0.5 MeV which are abrupt (bursty) with significant substructure (occasionally down to sub-second timescale). Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Using two years of ELFIN data, we assemble a statistical database of 50 events of strong EMIC wave-driven precipitation. Most reside at L=5-7 at dusk, while a smaller subset exists at L=8-12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L-shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of 1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven 1MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to 200-300 keV by much less intense higher frequency EMIC waves. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation.
The ELFIN Mission Angelopoulos, V; Tsai, E; Bingley, L ...
arXiv.org,
06/2020
Paper, Journal Article
Odprti dostop
The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (~93deg ...inclination), nearly circular, low-Earth (~450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (~90min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50keV to 5MeV electrons with deltaE/E<40% and a fluxgate magnetometer (FGM) on a ~72cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5Hz Nyquist (nominally) with <0.3nT/sqrt(Hz) noise at 1Hz. The spinning satellites (T_spin~3s) are equipped with magnetorquers that permit spin-up/down and reorientation maneuvers. The spin axis is placed normal to the orbit plane, allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250keV-5MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018.
Although historically research findings about racial and ethnic issues were all too often used to support prevailing concepts of racial inferiority, in recent years racial and ethnic factors have ...frequently been ignored. However, current findings suggest that racial and ethnic differences exist in the symptom presentations of psychiatric disorders. Significant racial differences have been noted among proposed biological markers for various psychiatric disorders, such as serum creatinine phosphokinase, platelet serotonin, and HLA-A2. Racial and ethnic differences in response to psychotropic medication, such as higher blood levels found among Asians, affect dosage requirements and potential side effects. All of these developments underline the importance of considering ethnic and racial factors in psychiatric research.
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