A Blue Spectral Shift of the Hemoglobin Soret Band Correlates with the Age (Time Since Deposition) of Dried Bloodstains

The ability to determine the time since deposition of a bloodstain found at a crime scene could prove invaluable to law enforcement investigators, defining the time frame in which the individual depositing the evidence was present. Although various methods of accomplishing this have been proposed, none has gained widespread use due to poor time resolution and weak age correlation. We have developed a method for the estimation of the time since deposition (TSD) of dried bloodstains using UV-VIS spectrophotometric analysis of hemoglobin (Hb) that is based upon its characteristic oxidation chemistry. A detailed study of the Hb Soret band (λmax = 412 nm) in aged bloodstains revealed a blue shift (shift to shorter wavelength) as the age of the stain increases. The extent of this shift permits, for the first time, a distinction to be made between bloodstains that were deposited minutes, hours, days and weeks prior to recovery and analysis. The extent of the blue shift was found to be a function of ambient relative humidity and temperature. The method is extremely sensitive, requiring as little as a 1 µl dried bloodstain for analysis. We demonstrate that it might be possible to perform TSD measurements at the crime scene using a portable low-sample-volume spectrophotometer

Point Defects and Diffusion in Ni₃Ga

ABSTRACTThe properties of intrinsic point defects and the self-diffusion behaviour of the constituent elements in Ni3Ga have been studied by positron annihilation, tracer diffusion and interdiffusion experiments. Thermal vacancies have been detected by positron lifetime measurements for specimens quenched from high temperatures. The vacancy formation energy is in the range between 1.7 and 1.8 eV, and is not dependent strongly on the composition. The tracer diffusion coefficients of Ni and Ga are of the same order of magnitude, and the interdiffusion coefficient is about 10 times larger than the diffusion coefficient of Ni. The diffusion in Ni3Ga has been found to satisfy the Darken-Manning equation, as expected from the model of the self-diffusion in this type of materials, where both the species of atoms are assumed to migrate primarily in the sub-lattice of the major element via the ordinary vacancy mechanism.</jats:p

Clinical Impact Correlation of a Delphi-Based Proximal Junctional Kyphosis Severity Scale and HRQOL

Introduction Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are adverse outcomes following adult spinal surgery (ASD) surgery. There is a lack of consensus regarding which patients (pts) require revision surgery. The Hart ISSG PJK severity scale correlates with the need for revision surgery. This study evaluates the Hart International Spine Study Group (ISSG) PJK severity scale and health-related quality of life (HRQOL) measures in pts with PJK. Patients and Methods All ASD pts with PJK and/or PJF who eventually underwent revision surgery were identified from two large academic medical centers. Pts were retrospectively assigned scores based on the Hart ISSG PJK severity scale: neurological status, focal pain, instrumentation problem, kyphosis severity/PLC integrity, UIV/UIV + 1 fracture, and level of UIV. Scores range from 0 to 15. Pre-PJK revision HRQOL measures included: Oswestry disability index (ODI), short-form 36 (SF-36), and Scoliosis Research Society questionnaire (SRS30). Scores were subcategorized into 0 to 2, 3 to 5, 6 to 8, 9 to 11, and 12 to 15, and differences in HRQOL outcomes were determined with linear regression. Correlation was assessed with a Pearson correlation coefficient. Results A total of 54 cases were included, out of which 31.5% were male, and the mean age was 64.9 years. The Hart ISSG PJK severity scale scores ranged from 4 to 15, with the median being 8. PJK/PJF occurred in the upper thoracic spine in 24.1% of the cases. 54.8% had fractures and 77.8% had instrumentation issues. Overall, 55.6% had neurological deficits, with 16.7% having weakness and/or myelopathy. All pts had preoperative pain (median VAS 9/10). While statistical significance on linear regression was not seen, there were obvious trends that correlated with the Hart ISSG PJK severity scale. Higher Hart ISSG PJK severity scale scores were associated with higher ODI (p = 0.283, r = 0.350), lower SRS30 function (p = 0.821, r = −0.323), and lower SRS mental (p = 0.646, r = −0.592). Conclusion The Hart ISSG PJK severity scale has been shown to be predictive in the decision making of when patients require revision surgery. Based on the current study, it may also correlate with functional outcomes, specifically ODI and SRS30 components