Less than 1% quantum defect fiber lasers via ytterbium-doped multicomponent fluorosilicate optical fiber.

Two ytterbium-doped fiber lasers exhibiting quantum defects of less than 1% are demonstrated, in which pumping at wavelengths of 976.6 and 981.0 nm yielded lasing at wavelengths of 985.7 and 989.8 nm, respectively. The multicomponent fluorosilicate active optical fiber, fabricated using the molten core method, has spectral characteristics similar to those of fluoride glasses, namely short average emission wavelength and long upper state lifetime. A best-case slope efficiency of 62.1% was obtained, matching the theoretical model very well. With further fiber and laser optimization, slope efficiencies approaching the quantum limit should ultimately be possible. A reduction in the quantum defect may offer significant mitigation of issues associated with fiber heating. As such, this work can serve as a possible direction for future scaling of high-power fiber laser systems.

Protein biomarker of cell proliferation determines survival to discharge in cases of equine large colon volvulus.

BACKGROUND: Progenitor cells play critical roles in epithelial repair following ischaemic injury. Protein biomarkers have been used to identify intestinal progenitor cell subpopulations. This study aims to determine if a critical number of intestinal progenitor cells can predict tissue viability and survival to discharge of large colon volvulus (LCV) cases. OBJECTIVES: The objectives were to 1) identify intestinal progenitor cell subpopulations using biomarkers: proliferating cell nuclear antigen (PCNA), sex determining region Y box 9 (SOX9), phospho-histone H3 (PHH3) and Ki-67, 2) define cut-off values for critical numbers of positive cells and 3) determine if survival to discharge is associated with cut-off values. STUDY DESIGN: Retrospective cohort study. METHODS: Adult horses admitted to the Farm and Equine Veterinary Medical Center at NC State's Veterinary Hospital and Peterson and Smith Equine Hospital between 2006 and 2016 that underwent an exploratory coeliotomy with a diagnosis of LCV of ≥360 degrees, had pelvic flexure biopsy and that recovered from general anaesthesia were selected for inclusion in the study. Immunohistochemical analyses were performed and positive cells were counted. Optimal cut-off values were determined using receiver operator curves. A Fisher's exact test was used to associate cut-off values with survival to discharge. RESULTS: In this study, 23 cases of LCV ≥360° were included. Of 23 horses, 13 (57%) survived to discharge. A cut-off value of <2.1 PHH3 positive cells per crypt correctly predicted death with 100% sensitivity (95% CI; 69.15-100%) and 84.62% specificity (95% CI; 54.55-98.08%). LCV cases with <2.1 PHH3 positive cells per crypt were 96.6 times more likely to die (95% CI; 4.14-2255 and P < 0.0001). Biomarkers PCNA, SOX9 and Ki-67 did not predict short-term survival. MAIN LIMITATIONS: The population size was small. CONCLUSIONS: PHH3 immunohistochemical analysis may assist in more accurate prediction of survival to hospital discharge of LCV cases. The summary is available in Spanish - see Supporting Information.

Highly nonlinear yttrium-aluminosilicate optical fiber with a high intrinsic stimulated Brillouin scattering threshold.

Highly nonlinear (high-NA small-mode-area) optical fibers also possessing an intrinsically high stimulated Brillouin scattering threshold are described. More specifically, silica clad, yttrium-aluminosilicate core fibers are shown to exhibit an intrinsically low Brillouin gain coefficient between 0.125 and 0.139×10-11 m/W and a Brillouin gain linewidth of up to 500 MHz. Losses on the order of 0.7 dB/m were measured, resulting from impurities in the precursor materials. Nonlinear refractive index values are determined to be similar to that of silica, but significant measurement uncertainty is attributed to the need to estimate dispersion curves since their direct measurement could not be made. The interest for highly nonlinear optical fibers with a low intrinsic Brillouin gain coefficient is expected to continue, especially with the growing developments of narrow-linewidth high-energy laser systems.

Single- and few-moded lithium aluminosilicate optical fiber for athermal Brillouin strain sensing.

Results are presented toward realizing a true single-mode fiber whose Brillouin frequency shift is independent of temperature, while its dependence on strain is comparable to conventional high-silica-content single-mode fibers. Demonstrated here is a fiber with a negative thermal sensitivity dν/dT of -0.26 MHz/K and a strain sensitivity of +406 MHz/%. The suppression of the Brillouin thermal response is enabled by the large thermal expansion coefficient of the group I oxide-containing silica glass network.

Brillouin scattering properties of lanthano-aluminosilicate optical fiber.

Utilizing measurements on a lanthano-aluminosilicate core optical fiber, the specific effects of lanthana (La2O3) on the Brillouin characteristics of silica-based oxide glass optical fibers are described. Lanthana is an interesting species to investigate since it possesses a wide transparency window covering the common fiber laser and telecom system wavelengths. As might be expected, it is found that the properties of lanthana are very similar to those of ytterbia (Yb2O3), namely, low acoustic velocity, wide Brillouin spectral width, and a negative photoelastic constant, with the latter two properties affording significant reductions to the Brillouin gain coefficient. However, lanthana possesses thermo-acoustic and strain-acoustic coefficients (acoustic velocity versus temperature or strain, TAC and SAC, respectively) with signs that are opposed to those of ytterbia. The lanthano-aluminosilicate (SAL) fiber utilized in this study is Brillouin-athermal (no dependence of the Brillouin frequency on temperature), but not atensic (is dependent upon the strain), which is believed to be, to the best of our knowledge, the first demonstration of such a glass fiber utilizing a compositional engineering approach.

Brillouin spectroscopy of a novel baria-doped silica glass optical fiber.

Presented here for the first time to the best of our knowledge is a detailed Brillouin spectroscopic study of novel, highly-BaO-doped silica glass optical fibers. The fibers were fabricated utilizing a molten-core method and exhibited baria (BaO) concentrations up to 18.4 mole %. Physical characteristics such as mass density, acoustic velocity, visco-elastic damping, and refractive index are determined for the baria component of the bariosilicate system. It is found that, of each of these parameters, only the acoustic velocity is less than that of pure silica. The effect of temperature and strain on the acoustic velocity also is determined by utilizing estimates of the strain- and thermo-optic coefficients. The dependencies are found to have signs opposite to those of silica, thus suggesting both Brillouin-frequency a-thermal and a-tensic binary compositions. Via the estimate of the strain-optic coefficient and data found in the literature, the Pockels' photoelastic constant p(12) is estimated, and both a calculation and measured estimate of the Brillouin gain versus baria content are presented. Such novel fibers incorporating the unique properties of baria could be of great utility for narrow linewidth fiber lasers, high power passive components (such as couplers and combiners), and Brillouin-based sensor systems.

[Septic shock in a patient with the Fournièr gangrene with fatal outcome]. / Septický sok u pacienta s Fournièrovou gangrénou s fatálním koncem.

AIM: The authors present a case of a patient with developed Fournièr gangrene and septic shock. Fournièr gangrene belongs to the group of local non-specific infection of soft tissues (NSTI). Its incidence is relatively low, but the infection is extraordinary aggressive with a possible lethal end. MATERIAL AND METHOD: 39 years old patient with 4 days history of Fournier gangrene's development was admitted in irreversible septic shock. The initial APACHE II score was 36. The delay in treatment was an important factor in the further course of illness with lethal end. RESULTS: Above the mentioned 39 years old patient died because of septic shock. The hemorrhagic cystitis was the original source of infection with further development of Fournièr gangrene according to the pathological record. CONCLUSION: We often come across all different kinds of stages of sepsis from the MODS to the septic shock for patients with Fournièr gangrene. Causal treatment should be started early. The local surgical excision and wide broad antibiotic administrations are basic treatments in the context of other treatment modalities according to the current patient's needs. The adjuvant hyperbaric oxygen treatment takes place in patients with Fournièr gangrene as well and is beneficial. The following factor even worsens the illness prognosis: delay in diagnostic, higher age, anorectal origin of infection, the amount of organ with dysfunction or failure, diabetes mellitus and significant immunodeficiency.

An attempted prospective testing of an asthma severity index and a quality of life survey for 1 year in ambulatory patients with asthma.

It has been recommended that allergist-immunologists use quality of life (QOL) surveys to document their "added value" in patient care. There are little cross-sectional or prospective data regarding longer term follow-up of patients using QOL assessments and none associated with prospective use of an asthma severity index (ASI). Our objective was to identify clinical and psychological correlates of adverse asthma outcomes as assessed using the ASI survey. A 12 item QOL and a nine item ASI survey, spirometry, and history and physical were obtained from patients initially and then every 3 months for a year. The ASI was calculated as follows: one point for each emergency treatment of asthma if not in status asthmaticus, three points for each hospitalization for status asthmaticus, and six points for each intensive care admission or intubation. Patients were 56 adults between ages 18 and 45 with asthma enrolled between May 1994 and February 1996 with the intention to be reassessed quarterly for a year. At enrollment the 56 patients had ASI scores for the previous 12 months ranging from zero to 30. The patient with an ASI of 30 did not return after the initial visit. Of the 13 patients who completed the study, 12 patients had a zero ASI score over a 12-month period; one patient who had an initial score of 26 finished with a score of one. There were no deaths throughout the follow-up period. Of the 43 patients who did not complete the study only six (13.9%) cited local managed care or primary care physician as taking over their care. Initial ASI scores were dichotomized (zero versus greater-than-zero) due to skewness. The forced expiratory volume in one second (FEV1), % predicted FEV1 and peak flow were not related significantly to the dichotomized ASI score. The strongest univariate predictor was the self-assessment of asthma burden using a 78 mm visual analog scale. A two variable model included a query about bodily pain in the last 4 weeks and a self-assessment of general health. The dropout rate was high but only 13.9% of such patients reported that managed care or primary care physicians were responsible. A two variable model was a strong predictor of asthma severity. The single best predictor of asthma severity was a visual analog scale based on the question "How do you think your asthma is?"

Epiglottitis in adults and children in Olmsted County, Minnesota, 1976 through 1990.

OBJECTIVE: To compare the initial clinical manifestations and sequelae of epiglottitis among children and adult residents of Olmsted County, Minnesota. MATERIAL AND METHODS: We conducted a population-based retrospective cohort study of all Olmsted County residents with the diagnosis of epiglottitis during the 15-year period from Jan. 1, 1976, through Dec. 31, 1990. RESULTS: From 1976 through 1990, 41 residents (20 children and 21 adults) of Olmsted County were diagnosed with epiglottitis. (One case in an adult was first diagnosed at autopsy and was included only in the incidence rates and analysis of seasonal and secular trends.) Children had a mean annual incidence rate of 4.25 per 100,000, whereas the rate in adults was 2.18 per 100,000. The age- and sex-adjusted incidence of epiglottitis decreased during the study period from 4.94 per 100,000 during 1976 through 1980 to 2.08 per 100,000 during 1986 through 1990. No seasonal effect was detected in adults or children. At initial assessment, adults tended to have pharyngeal symptoms (sore throat and odynophagia), cervical adenopathy, and ear pain, whereas children most often had respiratory (stridor, dyspnea, and retractions) and laryngeal symptoms. Proportionately, more children than adults received artificial airway support and had associated pneumonia. One death occurred in an adult, in whom the diagnosis was made at autopsy. CONCLUSION: The incidence of epiglottitis has decreased significantly in recent years. Children and adults have considerably different initial manifestations of epiglottitis.

Sexual experience effects are blocked both by the protein-synthesis inhibitor, cycloheximide, and by the noncompetitive NMDA antagonist, MK-801.

Three studies were done to determine the effects of a brief 2-h sexual experience on the maintenance of sexual behavior in male rats; the effects on the experience-based maintenance of sexual behavior of gonadal hormones (study 1), a protein-synthesis inhibitor (study 2), and an N-methyl-D-aspartate receptor blocker (study 3) were determined. Naive male rats were provided with a 2-h sexual experience with sexually receptive hormonally "primed" females or they received no experience. In the first study animals under each of these conditions then underwent castration or sham surgery. In the second study animals under each of the experience conditions received either cycloheximide (CYX) or saline (SAL; 1.5 or 3.0 mg/kg CYX or SAL sc, 10 min after the experience). In study 3 experienced and inexperienced animals received either 0.07 or 0.10 mg/kg MK-801 ip (15 min before the experience). In all studies animals were tested for sexual behavior 3, 6, and 9 days after surgery or injection. These studies showed that the most consistent effect of a 2-h sexual experience was to facilitate the initiation of mounting, especially on the first test; they show, further, that most experience effects were reduced or eliminated if animals were castrated between experience and test, if they received a drug (CYX) at the time of the experience that blocks the synthesis of proteins, or if they received an NMDA receptor antagonist prior to the experience.

Purification and properties of human serum carnosinase.

Carnosinase from human plasma was purified 18,000-fold to apparent homogeneity in a four step procedure. The dipeptidase was partially inactivated during DEAE-cellulose chromatography; however, it reactivated slowly when concentrated and stored at 4 degrees C. In the second purification step, hydroxylapatite column chromatography, two forms of the enzyme were separated from one another. Human serum carnosinase was found to be a glycoprotein with a pI of 4.4 and a subunit Mr of 75,000; the active enzyme was a dimer, the two subunits being connected by one or more disulfide bonds. The enzyme was especially active in hydrolyzing carnosine and anserine, preferring dipeptides with histidine in the C-terminal position. In most human tissues, the concentration of serum carnosinase was proportional to the percentage of trapped blood in the sample. However, the brain contained about 9 times more enzyme than expected, based on the amount of trapped blood present. The physiological function of this enzyme seems to be the hydrolysis of homocarnosine in the brain and the splitting of carnosine and anserine in the blood stream. Six higher primates were found to have serum carnosinase. Twelve nonprimate mammals were tested; all were lacking the serum enzyme except for the Golden hamster, which had very high concentrations of a carnosinase having somewhat different properties than the higher primate enzyme.

Comparative Analyses of Carbon Dynamics in Native and Cultivated Ecosystems.

Plant productivity, litter decomposition rates, and soil organic matter accumulation for winter wheat and for unbroken tallgrass prairie in Central Missouri were analyzed and compared. As measured in this 3-yr study, annual production of dry matter above- and belowground for the cultivated system averaged slightly higher than that for the natural vegetation burned every 3-4 yr. Prairie was characterized by greater year-to-year fluctuation of productivity, which in some years exceeded productivity of the cultivated system. More litter and structural biomass older than 1 yr occurred in the prairie, reflecting the perennial nature of the root system. Principal pathways of carbon transfer in both ecosystems were modeled, and mean residence time in major storage compartments estimated. Combined CO2 losses from above- and belowground litter decay, expressed as a percentage of total soil respiration, were twice as great under wheat as for native prairie. A relatively greater fraction of net primary production was available for synthesis of soil organic matter in native prairie. Under equilibrium conditions, decomposition constants for this compartment, however, were similar. Contrasts in community structure and phenology, seasonal dynamics of litter decay, and levels of soil disturbance are suggested influences affecting transfer and storage characteristics.

Challenge exposure of cattle vaccinated with a chemically altered strain of Pasteurella haemolytica.

Calves vaccinated with a chemically altered strain of Pasteurella haemolytica and their nonvaccinated controls were challenge exposed intranasally with the Cooper strain of infectious bovine rhinotracheitis virus. Five days later, the calves were challenge exposed intratracheally with the P haemolytica type A1. Calves that had been vaccinated with large, medium, or small doses of the chemically altered vaccinal strain of P haemolytica had various degrees of resistance to the experimental challenge exposure. Nonvaccinated animals developed severe respiratory tract disease and pneumonia after challenge exposure.

Homocarnosinosis: lack of serum carnosinase is the defect probably responsible for elevated brain and CSF homocarnosine.

Patients afflicted with homocarnosinosis have elevated concentrations of homocarnosine in brain and CSF. It has been reported that they lack brain homocarnosinase. However, we have found that these patients are deficient in serum carnosinase, a dipeptidase which hydrolyzes homocarnosine about 5% as rapidly as it splits carnosine. Homocarnosinase could not be detected in normal human brain extracts after isoelectric focusing or DEAE-cellulose column chromatography. The ability of brain extracts to hydrolyze homocarnosine thus appears to be attributable solely to the serum carnosinase which is present because of serum trapped in the brain sample. Preliminary data indicate that homocarnosinase is probably not present in 13 other human tissues. Normal CSF contained serum carnosinase, whereas the CSF of a homocarnosinosis patient was lacking this enzyme. Thus it appears that the elevated concentrations of homocarnosine in the CSF of homocarnosinosis patients are attributable to serum carnosinase deficiency.

Human serum carnosinase: characterization, distinction from cellular carnosinase, and activation by cadmium.

Human serum carnosinase was assayed using a simple and sensitive fluorometric method. Under optimum conditions, the average adult serum hydrolyzed 42 mu mol of carnosine per ml per hour, about 17 times the average activity reported in the literature. Cadmium was twice as effective as manganese as an activator of this enzyme. Serum carnosinase was found to be different in many respects from cellular carnosinase. For example, the serum isozyme hydrolyzed homocarnosine, whereas the cellular carnosinase did not. The apparent molecular weight of serum carnosinase was 160 000, while that of the cellular isozyme was 90 000. Although it has been reported that serum contains two molecular forms of carnosinase, only one form was detected using several electrophoretic methods and two ion exchange chromatography procedures. The concentration of serum carnosinase varied greatly between individuals. Little or no enzyme was detected in children below 10 months in age. Thereafter, the average concentration of carnosinase increased gradually to reach the adult range at age 13-15.

Cross-protection by a chemically altered vaccinal strain of Pasteurella multocida in mice and hamsters.

A chemically altered type A strain of Pasteurella multocida was used to vaccinate mice and hamsters. The vaccinated animals were challenge exposed with type A, B, and E isolated of P multocida. A degree of protection was afforded the vaccinated animals against homologous and heterologous challenge-exposure strains.