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Raman spectrometer
An improved Raman spectrometer is provided, having, in a preferred embodiment, a light source comprising an injection-locked laser diode array, a multipass cell to multiply the intensity of the light source, a dynamic gas sample focusing system, and an atomic vapor filter to remove the Rayleigh scattered light. The laser diode arrays are tuned to match an absorption band of the atomic vapor filter. The Raman scattered light passes virtually unattenuated through the filter to be recorded by a Fourier transform spectrometer or other spectrometer. This invention permits higher sensitivity and resolution than prior art Raman spectrometers, in particular permitting identification and measurement of Raman emissions that occur at low wave numbers. The light source of this invention can also be used in conjunction with optical notch filters and photodetectors to permit detection and measurement of preselected species in a sample.Board of Regents, University of Texas Syste
Effect of pulsed methylprednisolone on pain, in patients with HTLV-1-associated myelopathy
HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an immune mediated myelopathy caused by the human T-lymphotropic virus type 1 (HTLV-1). The efficacy of treatments used for patients with HAM/TSP is uncertain. The aim of this study is to document the efficacy of pulsed methylprednisolone in patients with HAM/TSP. Data from an open cohort of 26 patients with HAM/TSP was retrospectively analysed. 1g IV methylprednisolone was infused on three consecutive days. The outcomes were pain, gait, urinary frequency and nocturia, a range of inflammatory markers and HTLV-1 proviral load. Treatment was well tolerated in all but one patient. Significant improvements in pain were: observed immediately, unrelated to duration of disease and maintained for three months. Improvement in gait was only seen on Day 3 of treatment. Baseline cytokine concentrations did not correlate to baseline pain or gait impairment but a decrease in tumour necrosis factor-alpha (TNF-α) concentration after pulsed methylprednisolone was associated with improvements in both. Until compared with placebo, treatment with pulsed methylprednisolone should be offered to patients with HAM/TSP for the treatment of pain present despite regular analgesia
A Novel Classification System to Address Financial Impact and Referral Decisions for Bile Duct Injury in Laparoscopic Cholecystectomy
Purpose. The study was undertaken to evaluate a novel
classification system developed to estimate financial cost of bile
duct injury (BDI) and to aid in decision making for referral.
Study Design. A retrospective review of
patients referred for BDI was performed. Grade I injuries involve the
duct of Luschka or accessory right hepatic ducts, grade II includes
all other biliary injuries, and grade III includes all vasculobiliary
injuries. Groups were compared using standard statistical methods.
Results. There were 14 grade I, 74 grade II,
and 20 grade III injuries. There was a significant difference in the
cost and mortality of grade I (46,481, 1.4%),
and grade III ($69,368, 15%,
P = 0.002
and
P = 0.030,
resp.) injuries. Grade II and III injuries were significantly more
likely to require surgical repair (OR 27.7,
P < 0.001).
Conclusion. We have presented a simple
classification system that is able to accurately predict cost and need
for surgical repair
Surgical resection for hilar cholangiocarcinoma: experience improves resectability
AbstractObjectivesIn hilar cholangiocarcinoma, resection provides the only opportunity for longterm survival. A US experience of hilar cholangiocarcinoma was examined to determine the effect of clinical experience on negative margin (R0) resection rates.MethodsWe conducted a retrospective analysis of 110 consecutive hilar cholangiocarcinoma patients presenting over an 18-year period. Analyses were performed using chi-squared, Wilcoxon rank sum and Kaplan–Meier methods, and multivariable Cox and logistic regression modelling.ResultsOf the 110 patients in the cohort, 59.1% were male and 90.9% were White. The median patient age was 64 years. A total of 59 (53.6%) patients underwent resection; 37 of these demonstrated R0. The 30-day mortality rate was 5.1%; the complication rate was 39.0%. The rate of resectability increased over time (36.4% vs. 70.9%; P= 0.001), as did the percentage of R0 resections (10.9% vs. 56.5%; P < 0.001). Of the 59 patients who underwent resection, 23 (39.0%) experienced recurrence. Multivariable Cox regression analysis identified resection margins [hazard ratio (HR) = 4.124 for positive vs. negative; P= 0.002] and type of operation (HR = 5.075 for exploration vs. resection; P= 0.001) as significant to survival.ConclusionsAlthough R0 resection can be achieved in only a minority of patients, these patients have a reasonable chance of longterm survival. The last decade has seen a significant rise in rates of resectability of Klatskin's tumour at specialty centres
Requirements for Investigating the Connection Between Lyman Alpha Absorption Clouds and the Large-Scale Distribution of Galaxies
We model the requirements on observational data that would allow an accurate
determination of the degree of association between Lyman alpha absorbers and
peaks in the redshift distribution of galaxies (large-scale structures like
clusters of galaxies). We compare simulated distributions of low-redshift Lyman
alpha absorption systems, constrained to be consistent with the distribution
observed with HST, with the large-scale distribution of galaxies determined
from pencil-beam redshift surveys. We estimate the amount of observational data
required from catalogues of Lyman alpha absorbers and galaxies to allow a
statistically significant test of the association of absorbers with large-scale
structures of galaxies.
We find that for each line-of-sight observed for Lyman alpha absorption lines
(assuming that the entire redshift range out to z=0.4 is observable), redshifts
must be obtained for at least 18 galaxies brighter than Mb=-18 and having
redshifts between 0.2 and 0.4. Based on the redshift surveys used in this
study, a search radius of 10' from the quasar line-of-sight is required. This
will ensure that all peaks in the galaxy redshift distribution are represented
by at least one galaxy in the observed sample. If Lyman alpha absorbers are
intrinsically uncorrelated with galaxies, we find that 8 lines-of-sight must be
observed to show that the distributions are different at the 95% confidence
level. However, if a fraction of the Lyman alpha absorbers are distributed with
the peaks in the galaxy distribution, 38 lines-of-sight must be mapped for the
distribution of both Lyman alpha absorbers and galaxies in order to determine
the fraction of absorbers distributed with the peaks of the galaxy distribution
to an accuracy of 10%.Comment: 17 pages LaTeX file, plus 6 uuencoded compressed .eps figures to be
printed seperately, to appear in Feb. 1, 1996 Ap
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