Search

A sampling system for measuring emissions of non-volatile particulate matter (nvPM) from aircraft gas turbine engines has been developed to replace the use of smoke number and is used for international regulatory purposes (SAE 2018; ICAO 2017). This sampling system can be up to 35 m in length. The sampling system length in addition to the volatile particle remover (VPR) and other sampling system components lead to substantial particle losses, which are a function of the particle size distribution, ranging from 50 to 90% for particle number concentrations and 10-50% for particle mass concentrations. The particle size distribution is dependent on engine technology, operating point, and fuel composition. Any nvPM emissions measurement bias caused by the sampling system will lead to unrepresentative emissions measurements which limit the method as a universal metric. Hence, a method to estimate size dependent sampling system losses using the system parameters and the measured mass and number concentrations was also developed (SAE 2017; SAE 2019). An assessment of the particle losses in two principal components used in ARP6481 (SAE 2019) was conducted during the VAriable Response In Aircraft nvPM Testing (VARIAnT) 2 campaign. Measurements were made on the 25-meter sample line portion of the system using multiple, well characterized particle sizing instruments to obtain the penetration efficiencies. An agreement of ±15% was obtained between the measured and the ARP6481 method penetrations for the 25-meter sample line portion of the system. Measurements of VPR penetration efficiency were also made to verify its performance for aviation nvPM number. The research also demonstrated the difficulty of making system loss measurements and substantiates the E-31 decision to predict rather than measure system losses.

The fine particulate matter (PM) emissions from the use of two types of Fischer-Tropsch aviation fuels and their 50:50 blends with military JP-8 were quantified as part of the first Alternative Aviation Fuel Experiment (AAFEX). Measurements were made at 30-m downstream of a CFM56–2C1 engine for PM mass and number, particle size distribution, black carbon (BC), and volatile PM (sulfate + organics) using selected on-line instrumentation. The PM number emission index (EI(N)) ranged from ~ 2 × 10(15) to 7 × 10(16) particles/kg fuel burned depending on fuel flow, fuel composition, and sampling temperature with the magnitude of the emissions inversely correlated to fuel flow. The PM mass emissions (EI(M)) measured in the study varied from ~ 5 to 680 mg/kg fuel again depending on fuel flow, fuel type, and sampling temperature with a characteristic U-shaped curve of EI(M) with respect to fuel flow observed from the data. At low fuel flow (corresponding to low engine power), particle number and volume size distributions contained a single mode whereas at higher engine power, a bi-modal distribution was observed. The BC emissions varied from ~ 3 to 415 mg/kg fuel depending on fuel type and were found to exponentially increase with engine power (fuel flow). The volatile PM varied with sample temperature, fuel type, and increasing fuel flow within the range of EIs from ~ 0.4 to 11 mg/kg fuel with the highest values being at low fuel flow. Finally, the use of the two neat alternative fuels reduced the EI(N) by a median value of 70–73% and the EI(M) by ~ 94% as compared to JP-8 across all power conditions tested.

While developed nations are accustomed to the challenge of intermittent renewable sources on a stable grid, for the developing world, the problem is different: the grid itself is unreliable. Those affected turn to diesel backup generators. Once this investment has been made, resistance hardens against investments in more sustainable alternatives. However, the high cost of diesel makes a case for diesel+solar hybrids - already commonplace for off-grid applications - in these grid-tied systems as well. Displacing diesel fuel for just a few hundred hours each year can raise the project rate of return by several percent. The benefit of grid-tied diesel+solar is illustrated using a notional commercial/industrial PV project in India.

A 25-MW solar power plant was commissioned in Andhra Pradesh, India in the first quarter of 2016. The 3 MW of single-axis tracker arrays co-located with 22 MW of fixed-tilt arrays provide a direct comparison of their performance under variable irradiance and thermal conditions to inform the cost-benefit analysis of future installations. Through March 2019, the single-axis tracker arrays have delivered an increase in energy yield of more than 14%.

Purpose This study evaluated the impact of an admission medication reconciliation process conducted by student pharmacists during an introductory pharmacy practice experience (IPPE). Methods Patients aged 18 years or older admitted to a general medicine service and who received medication reconciliation from a student pharmacist were included. Data were collected retrospectively from electronic medical records. Results Student pharmacists performed medication reconciliation on 21.8% of 6395 patients admitted to the target service, directly involving the majority of patients/caregivers (78.9%) in the process. Potential medication discrepancies were found in 43.8% of patients; the average number of potential discrepancies found per patient was 1.0 ± 1.6. The most common potential discrepancy was “omitted prescription medication.” Prescribers responded to notification about potential discrepancies by correcting or clarifying 74.9% of all potential discrepancies and 77.2% of discrepancies with the potential to causes severe patient discomfort or clinical deterioration. Conclusion IPPE student pharmacists contributed to patient care by performing medication reconciliation on patient admission to hospital. Student pharmacists identified and facilitated correction of unrecognized medication issues that could have adversely impacted patient well-being.

Predictive performance comparison has been made for four types of photovoltaics (PV) modules: cadmium telluride, multicrystalline silicon, copper indium gallium selenide, and monocrystalline silicon. Representative spectral response and nameplate specifications were used to determine the performance under operating conditions in Albuquerque, NM, USA. Hour-by-hour spectra were derived via archived meteorological data. Use of this modeled spectra enables sensitivity analysis of the energy yield and revenue potential of competing PV module types and determination of new target spectra for future design optimization.

Thermal–optical analysis (TOA) is a widely used technique that fractionates carbonaceous aerosol particles into organic and elemental carbon (OC and EC), or carbonate. Thermal sub-fractions of evolved OC and EC are also used for source identification and apportionment; thus, oven temperature accuracy during TOA analysis is essential. Evidence now indicates that the "actual" sample (filter) temperature and the temperature measured by the built-in oven thermocouple (or set-point temperature) can differ by as much as 50 °C. This difference can affect the OC–EC split point selection and consequently the OC and EC fraction and sub-fraction concentrations being reported, depending on the sample composition and in-use TOA method and instrument. The present study systematically investigates the influence of an oven temperature calibration procedure for TOA. A dual-optical carbon analyzer that simultaneously measures transmission and reflectance (TOT and TOR) is used, functioning under the conditions of both the National Institute of Occupational Safety and Health Method 5040 (NIOSH) and Interagency Monitoring of Protected Visual Environment (IMPROVE) protocols. The application of the oven calibration procedure to our dual-optics instrument significantly changed NIOSH 5040 carbon fractions (OC and EC) and the IMPROVE OC fraction. In addition, the well-known OC–EC split difference between NIOSH and IMPROVE methods is even further perturbed following the instrument calibration. Further study is needed to determine if the widespread application of this oven temperature calibration procedure will indeed improve accuracy and our ability to compare among carbonaceous aerosol studies that use TOA.

Kisspeptin plays a pivotal role in pubertal onset and reproductive function. In rodents, kisspeptin perikarya are located in 2 major populations: the anteroventral periventricular nucleus and the hypothalamic arcuate nucleus (ARC). These nuclei are believed to play functionally distinct roles in the control of reproduction. The anteroventral periventricular nucleus population is thought to be critical in the generation of the LH surge. However, the physiological role played by the ARC kisspeptin neurons remains to be fully elucidated. We used bilateral stereotactic injection of recombinant adeno-associated virus encoding kisspeptin antisense into the ARC of adult female rats to investigate the physiological role of kisspeptin neurons in this nucleus. Female rats with kisspeptin knockdown in the ARC displayed a significantly reduced number of both regular and complete oestrous cycles and significantly longer cycles over the 100-day period of the study. Further, kisspeptin knockdown in the ARC resulted in a decrease in LH pulse frequency. These data suggest that maintenance of ARC-kisspeptin levels is essential for normal pulsatile LH release and oestrous cyclicity.

Residential wood-fired hydronic heaters (RWHHs) can negatively impact the local ambient air quality and thus are an environmental concern in wood burning areas of the U. S. Only a few studies have been conducted which characterize the emissions from RWHHs. To address the lack of emissions data, a study was conducted on four appliances of differing design using multiple fuel types to determine their thermal, boiler, and combustion efficiency as well as the emissions of carbon dioxide (CO 2 ), carbon monoxide (CO), total hydrocarbons (THC), nitrous oxide (N 2 O), methane (CH 4 ), total particulate matter (PM) mass, and particle number as well as particle size distribution (PSD). Three of these appliances were fired with split-log cordwood with the fourth unit using hardwood pellets. The measured thermal efficiencies for the appliances tested varied from 22 to 44% and the combustion efficiencies from 81 to 98%. Depending on appliance and fuel type, the emission factors ranged from about 1300 to 1800 g kg −1 dry fuel for CO 2 , 8–190 g kg −1 dry fuel for CO, −1 dry fuel for THC and 6–120 mg kg −1 for N 2 O. For the particle phase pollutants, the PM mass emission factors ranged from 0.31 to 47 g kg −1 dry fuel and the PM number emission factors from 8.5 × 10 10 to 2.4 × 10 14 particles kg −1 dry fuel, also depending on the appliance and fuel tested. The PSD for all four appliances indicated a well established accumulation mode with evidence of a nucleation mode present for Appliances A and B. The average median aerodynamic particle diameters observed for the four appliances ranged from 84 to 187 nm while burning red oak or pellets. In general, the pellet-burning appliance had the highest overall operating efficiency and lowest emissions of the four units tested.

The UK MRC ALL97 trial included a randomised comparison of the efficacy and toxicity of dexamethasone and thioguanine (TG, experimental arms) with prednisolone and mercaptopurine (MP). The cytotoxic effects of MP and TG are mediated, in part, by thioguanine nucleotide (TGN) metabolites. TGNs are formed directly from TG whereas MP produces intermediate metabolites which are substrates for the enzyme thiopurine methyltransferase (TPMT). TPMT is under the control of a common genetic polymorphism. Both drugs are good substrates for TPMT. Both drugs undergo oxidative metabolism, but TG requires prior deamination. Consecutive children with ALL, diagnosed in the United Kingdom and Ireland between April 1997 and June 2002, were randomised to receive either TG or MP in maintenance courses. All patients received TG in intensification courses. Toxicity data was collected by an adverse event reporting system with follow-up questionnaires to seek detailed information on specific toxicities. Red blood cell (RBC) TGN concentrations and TPMT activities were measured by standard techniques in specific sub-groups. Of 1498 randomised patients, 750 were allocated TG and 748 MP. The trial produced a 5 year event-free survival (EFS) of 80%, with no difference in EFS or overall survival between thiopurine arms. However, TG was associated with an acute hepatitis syndrome with features of veno-occlusive disease (VOD) in 95 patients. Eighty-two of these were in the randomised TG arm (11% of TG recipients), the remaining were patients allocated MP who developed VOD during TG intensification courses. On long term follow-up, 43 (5.7%) TG recipients developed persistent splenomegaly and mild to moderate thrombocytopenia due to portal hypertension. TPMT activities were measured in 73 of the 95 VOD children at a standard protocol dose of thiopurine. For comparison, TPMT activities were measured in children who did not develop VOD or splenomegaly; there was no difference in the range of TPMT activities measured at 40mg/m2 TG (n = 83, median 15.4 units/ml RBCs) compared to 75mg/m2 MP (n = 78, median 15.2 units). Median TPMT activities in these 161 children, taking thiopurines at the protocol standard dose, were 15.2 units (range 5.8 to 23) compared to a median of 13.4 units (range 5.8 to 23) in the 73 VOD children (median difference 1.8 units, 95% CI 0.9 to 2.7, p < 0.001). A similar difference in TPMT activity was also seen when comparing persistent splenomegaly cases with controls. There was no difference in accumulation of TGNs at comparable doses. When used for maintenance therapy, TG causes liver toxicity in a significant minority of children with ALL without improving long term survival. An association with polymorphic variations in TPMT levels, a critical enzyme in thiopurine metabolism, implicates inter-individual variations in metabolism of the drug as a mechanism for liver damage, and points to a possible means of identifying at-risk patients. MP should remain the standard thiopurine for maintenance therapy unless longer follow-up reveals a survival advantage in favour of TG, and the mechanisms of liver toxicity are understood to avoid exposure of at risk patients.

To investigate whether the advancement of puberty in response to high-fat diet (HFD) results from a concomitant increase in LH pulse frequency and kisspeptin (Kiss1) and neurokinin B (NKB) signaling in the hypothalamus, blood samples were collected on postnatal day (pnd) 28, 32, or 36 for LH measurement and vaginal opening monitored as a marker of puberty in female rats fed with HFD or standard chow from weaning. Quantitative RT-PCR was used to determine Kiss1 and kisspeptin receptor (Kiss1r) mRNA levels in brain punches of the medial preoptic area and the arcuate nucleus (ARC), and NKB and NKB receptor (NK3R) mRNA levels in the ARC. There was a gradual increase in LH pulse frequency from pnd 28, reaching significance by pnd 36 in control diet-fed rats. The advancement of puberty by approximately 6 d (average pnd 34) in rats fed HFD was associated with an earlier onset of the higher LH pulse frequency that was already extant on pnd 28. The increased levels of expression of Kiss1 in the medial preoptic area and ARC, and NKB in the ARC, associated with pubertal onset were similarly advanced in HFD-fed rats. These data suggest that the earlier accelerated GnRH pulse generator frequency and advanced puberty with obesogenic diets might be associated with premature up-regulation of kisspeptin and NKB signaling in the hypothalamus of the female rat.

Multijunction solar cells based on III-V semiconductors, having recently demonstrated 43.5%, remain the world's most efficient solar cells, and the preferred technology in point-focus and dense-array concentrator photovoltaic (CPV) system architectures. The year 2011 proved to be a pivotal year for CPV technology, with multiple power plant installations in the megawatt to tens of megawatt scale. Spectrolab is working closely with CPV system manufacturers to provide a reliable and well-characterized cell technology, in volumes commensurate with this increasing demand. The evolutionary C3MJ+ and the C4MJ cell technologies are the latest in a sequence of CPV solar cell designs, with conversion efficiencies approaching or greater than 40%. Both technologies have completed detailed characterization and qualification programs, including accelerated laboratory and (for C4MJ) on-sun reliability testing, and have entered into high volume production at Spectrolab's manufacturing facility in Sylmar, CA. The metamorphic C4MJ technology affords new opportunities to optimize cell designs, taking into consideration both the spectral optical transmittance of a particular CPV system and the installation site's average solar resource over a typical meteorological year.

Animal models have enabled investigation of the complex mechanisms underlying energy homeostasis and, therefore, the development of antiobesity drugs.

[Figure][1] The standards of the Accreditation Council for Pharmacy Education (ACPE) for doctor of pharmacy programs require pharmacy curricula to provide students with introductory pharmacy practice experiences (IPPEs), which are defined as “practice experiences offered in various

The bed nucleus of the stria terminalis (BNST) occupies a central position in the neural circuitry regulating the hypothalamic-pituitary-adrenocortical axis response to stress. The potential role of the BNST in stress-induced suppression of the gondotrophin-releasing hormone (GnRH) pulse generator, the central regulator of the reproductive system, was assessed by examining the effects of micro-infusion of corticotrophin-releasing factor (CRF) or its antagonist into the BNST on pulsatile luteinising hormone (LH) secretion or stress-induced inhibition of LH pulses, respectively. Ovariectomised oestrogen-treated rats were implanted chronically with bilateral cannulae in the dorsolateral BNST and i.v. catheters. CRF (25, 50 or 100 pmol in 200 nl of artificial cerebrospinal fluid) administered bilaterally into the BNST resulted in a dose-dependent decrease in LH pulse frequency, and induced Fos expression in glutamic acid decarboxylase immunostained neurones in the medial preoptic area. These results suggest that the activation of hypothalamic GABAergic neurones in response to intra-BNST administration of CRF may be involved in the suppression of LH pulses. Furthermore, administration of CRF antagonist (280 pmol astressin-B, three times at 20-min intervals) into the BNST effectively blocked the suppression of pulsatile LH secretion in response to restraint (1 h) but not hypoglycaemic (0.25 U insulin/kg, i.v.) stress. These data suggest that CRF innervation of the dorsolateral BNST plays a key, but differential, role in stress-induced suppression of the GnRH pulse generator.

The fine particulate matter (PM) emissions from nine commercial aircraft engine models were determined by plume sampling during the three field campaigns of the Aircraft Particle Emissions Experiment (APEX). Ground-based measurements were made primarily at 30 m behind the engine for PM mass and number concentration, particle size distribution, and total volatile matter using both time-integrated and continuous sampling techniques. The experimental results showed a PM mass emission index (EI) ranging from 10 to 550 mg kg −1 fuel depending on engine type and test parameters as well as a characteristic U-shaped curve of the mass EI with increasing fuel flow for the turbofan engines tested. Also, the Teflon filter sampling indicated that ∼40–80% of the total PM mass on a test-average basis was comprised of volatile matter (sulfur and organics) for most engines sampled. The number EIs, on the other hand, varied from ∼10 15 to 10 17 particles kg −1 fuel with the turbofan engines exhibiting a logarithmic decay with increasing fuel flow. Finally, the particle size distributions of the emissions exhibited a single primary mode that were lognormally distributed with a minor accumulation mode also observed at higher powers for all engines tested. The geometric (number) mean particle diameter ranged from 9.4 to 37 nm and the geometric standard deviation ranged from 1.3 to 2.3 depending on engine type, fuel flow, and test conditions.

Puberty is a developmental process that is dependent upon activation of the hypothalamic gonadotrophin-releasing hormone (GnRH) pulse generator. It is well established that the stress neuropeptide, corticotrophin-releasing factor (CRF), has a profound inhibitory action on GnRH pulse generator frequency. Although stress is known to affect the timing of puberty, the role of CRF is unknown. The present study aimed to test the hypothesis that CRF plays a critical role in the timing of puberty. On postnatal day (pnd) 28, female rat pups were chronically implanted with i.c.v. cannulae and received 14 days of administration of either CRF, CRF receptor antagonist (astressin-B) or artificial cerebrospinal fluid via an osmotic mini-pump. A separate group of rats served as nonsurgical controls. As a marker of puberty, rats were monitored for vaginal opening and first vaginal oestrus. Levels of CRF, CRF receptor types 1 and 2 (CRF-R1, CRF-R2) mRNA expression in micropunches of the medial preoptic area (mPOA), hypothalamic paraventricular nucleus (PVN) and arcuate nucleus (ARC) were determined across pubertal development; brain tissue was collected from a naive group of rats on pnd 14, 32, on the day of vaginal opening, and pnd 77 (Adult). Administration of CRF resulted in a delay in the onset of puberty, whereas astressin-B advanced pubertal onset. Additionally, CRF and CRF-R1 mRNA expression was reduced in the mPOA, but not ARC, at puberty. In the PVN, expression of CRF, but not CRF-R1 mRNA, was reduced at the time of puberty. These data support the hypothesis that CRF signalling may play an important role in modulating the timing of puberty in the rat.

The fine particle emissions from a U. S. certified non-catalytic wood stove and a zero-clearance fireplace burning Quercus rubra L. (northern red oak) and Pseudotsuga menziesii (Douglas fir) cordwood each at two different moisture levels were determined. Emission testing was performed using both time-integrated and continuous instrumentation for total particle mass, particle number, particle size distribution, and fixed combustion gases using an atmospheric wind tunnel, full-flow laboratory dilution tunnel, and dilution stack sampler with a comparison made between the three dilution systems and two sampling filter types. The total mass emission factors (EFs) for all dilution systems and filter media are extremely variable ranging from −1 of dry wood depending on the combination of appliance type, wood species and moisture content, filter medium, and dilution system. For Teflon filter sampling of stove emissions in the wind tunnel, the total mass EFs varied from ∼2 to 8 g kg −1 of dry fuel depending on wood type whereas the equivalent fireplace emissions burning wet oak averaged 11 g kg −1 . A substantial number of ultrafine particles in the accumulation size range were also observed during all tests as determined by an Electrical Low Pressure Impactor (ELPI) and Scanning Mobility Particle Sizer. The PM-2.5 (particles ≤2.5 μm in aerodynamic diameter) fractions determined from the ELPI electrometer data ranged from 93 to 98% (mass) depending on appliance type as reported previously by Hays et al. (Aerosol Science, 34, 1061, 2003) .

The orexigenic gut peptide ghrelin negatively modulates the hypothalamic-pituitary-gonadal (HPG) axis. Hyperghrelinaemia results during negative energy balance, a state often associated with delayed puberty and disrupted fertility, whilst exogenous ghrelin suppresses pulsatile luteinising hormone (LH) secretion. The recent identification of kisspeptin (Kiss1) and its G protein-coupled receptor (GPR)54 (Kiss1r) as an essential component of the HPG axis controlling gonadotrophin secretion raises the possibility that kisspeptin-Kiss1r signalling may play a critical role in the transduction of ghrelin-induced suppression of LH. Ovariectomised oestrogen-replaced rats were implanted with intravenous catheters and blood samples collected for detection of LH pulses prior to and after intravenous administration of ghrelin (3nM/250 microl) or saline (250 microl) during ad libitum feeding or after overnight fasting. Quantitative RT-PCR was used to determine Kiss1 and Kiss1r mRNA levels in brain punches of the key hypothalamic sites regulating gonadotrophin secretion, the medial preoptic area (mPOA) and arcuate nucleus (ARC), collected 6h following administration of ghrelin. Ghrelin significantly lowered LH pulse frequency in fed rats, an effect significantly enhanced by food deprivation. Fasting, ghrelin or their combination down-regulated Kiss1, without affecting Kiss1r, expression in the mPOA, and affected the expression of neither in the ARC. Considering the pivotal role for kisspeptin signalling in the activation of the HPG axis, the ability of ghrelin to down-regulate Kiss1 expression in mPOA may be a contributing factor in ghrelin-related suppression of pulsatile LH secretion.

Immunological challenge experienced in early life can have long-term programming effects on the hypothalamic-pituitary-adrenal axis that permanently influence the stress response. Similarly, neonatal exposure to immunological stress enhances stress-induced suppression of the hypothalamic-pituitary gonadal (HPG) axis in adulthood, but may also affect earlier development, including the timing of puberty. To investigate the timing of the critical window for this programming of the HPG axis, neonatal female rats were injected with lipopolysaccharide (LPS; 50 microg/kg i.p.) or saline on postnatal days 3 + 5, 7 + 9, or 14 + 16 and monitored for vaginal opening and first vaginal oestrus as markers of puberty. We also investigated the effects of neonatal programming on the development of the expression patterns of kisspeptin (Kiss1) and its receptor (Kiss1r) in hypothalamic sites known to contain kisspeptin-expressing neuronal populations critical to reproductive function: the medial preoptic area (mPOA) and the arcuate nucleus in neonatally-stressed animals. We determined that the critical period for a significant delay in puberty as a result of neonatal LPS exposure is before 7 days of age in the female rat, and demonstrated that Kiss1, but not Kiss1r mRNA, expression in the mPOA is down-regulated in pre-pubertal females. These data suggest that the mPOA population of kisspeptin neurones play a pivotal role in controlling the onset of puberty, and that their function can be affected by neonatal stress.

Concerns about the changing environment and fossil fuel depletion have prompted much controversy and scrutiny. One way to address these issues is to use concentrating photovoltaics (CPV) as an alternate source for energy production. Multijunction solar cells built from III–V semiconductors are being evaluated globally in CPV systems designed to supplement electricity generation for utility companies. The high efficiency of III–V multijunction concentrator cells, with demonstrated efficiency over 40% since 2006, strongly reduces the cost of CPV systems, and makes III–V multijunction cells the technology of choice for most concentrator systems today. In designing multijunction cells, consideration must be given to the epitaxial growth of structures so that the lattice parameter between material systems is compatible for enhancing device performance. Low resistance metal contacts are crucial for attaining high performance. Optimization of the front metal grid pattern is required to maximize light absorption and minimize I2R losses in the gridlines and the semiconductor sheet. Understanding how a multijunction device works is important for the design of next-generation high efficiency solar cells, which need to operate in the 45%–50% range for a CPV system to make better economical sense. However, the survivability of solar cells in the field is of chief concern, and accelerated tests must be conducted to assess the reliability of devices during operation in CPV systems. These topics are the focus of this review.

The spectral response of concentrator multijunction solar cells has been measured over a temperature range of 25–75°C. These data are combined with reference spectra representing the AM1·5 standard as well as annual spectral irradiance at representative geographical locations. The results suggest that higher performance in the field may be obtained if multijunction cells are designed for an effective air mass higher than AM1·5. Copyright © 2008 John Wiley & Sons, Ltd.

The performance of multijunction solar cells has been measured over a range of temperatures and illumination intensities. Temperature coefficients have been extracted for three-junction cell designs that are in production and under development. A simple diode model is applied to the three-junction performance as a means to predict performance under operating conditions outside the test range. These data may be useful in guiding the future optimization of concentrator solar cells and systems. Copyright © 2008 John Wiley & Sons, Ltd.

The high efficiency of multijunction concentrator cells has the potential to revolutionize the cost structure of photovoltaic electricity generation. Advances in the design of metamorphic subcells to reduce carrier recombination and increase voltage, wide-band-gap tunnel junctions capable of operating at high concentration, metamorphic buffers to transition from the substrate lattice constant to that of the epitaxial subcells, concentrator cell AR coating and grid design, and integration into 3-junction cells with current-matched subcells under the terrestrial spectrum have resulted in new heights in solar cell performance. A metamorphic Ga0.44In0.56P/Ga0.92In0.08As/ Ge 3-junction solar cell from this research has reached a record 40.7% efficiency at 240 suns, under the standard reporting spectrum for terrestrial concentrator cells (AM1.5 direct, low-AOD, 24.0 W/cm2, 25∘C), and experimental lattice-matched 3-junction cells have now also achieved over 40% efficiency, with 40.1% measured at 135 suns. This metamorphic 3-junction device is the first solar cell to reach over 40% in efficiency, and has the highest solar conversion efficiency for any type of photovoltaic cell developed to date. Solar cells with more junctions offer the potential for still higher efficiencies to be reached. Four-junction cells limited by radiative recombination can reach over 58% in principle, and practical 4-junction cell efficiencies over 46% are possible with the right combination of band gaps, taking into account series resistance and gridline shadowing. Many of the optimum band gaps for maximum energy conversion can be accessed with metamorphic semiconductor materials. The lower current in cells with 4 or more junctions, resulting in lower I2R resistive power loss, is a particularly significant advantage in concentrator PV systems. Prototype 4-junction terrestrial concentrator cells have been grown by metal-organic vapor-phase epitaxy, with preliminary measured efficiency of 35.7% under the AM1.5 direct terrestrial solar spectrum at 256 suns.

Kisspeptins are extraordinarily potent in stimulating gonadotropic hormone secretion via an action on the hypothalamic GnRH neural system. Because the physiological frequency of the GnRH pulse generator is a critical component of the control system that governs reproductive processes, the aim of this study was to examine the effect of kisspeptin-10 on pulsatile LH secretion and on the electrophysiological manifestation of GnRH pulse generator activity to determine frequency modulatory effects. Adult Sprague Dawley rats were ovariectomized and chronically implanted with electrodes in the arcuate nucleus to record the characteristic increases in hypothalamic multiunit electrical activity volleys coincident with the initiation of each LH pulse measured in peripheral blood and/or indwelling cardiac catheters for the collection of blood samples (25 microl) every 5 min for 6-7 h for the measurement of LH. Intravenous infusion of kisspeptin-10 (7.5, 35, and 100 nmol) induced a dose-dependent increase in LH secretion. The stimulatory effect of kisspeptin-10 (100 nmol) on LH secretion was blocked by the GnRH antagonist cetrorelix, precluding a singular action on gonadotropes. Unexpectedly, however, the marked increase in LH release in response to kisspeptin-10 (100 nmol) administration was not accompanied by any change in multiunit electrical activity volley frequency. It seem unlikely, therefore, that kisspeptin-10 has an appreciable frequency modulatory effect on GnRH pulse generator activity in the female rat.

The study was conducted to determine if enteral glutamine, 0.65 g kg(-1) daily for 7 days, is effective in reducing the incidence and severity of mucositis in paediatric oncology patients when given alongside chemotherapy. The study was carried out at St James's University Hospital, Leeds, UK.This was a randomized study using the patients as their own controls. Seventy-six patients undergoing treatment for paediatric malignancy having at least two identical courses of chemotherapy and at risk of developing mucositis participated in the study. Patients received one course of chemotherapy with glutamine and an identical course without. Alternate patients were allocated to have glutamine with course 1 or with course 2. The severity of symptoms of mucositis and the duration of enteral and parenteral nutrition were recorded. Daily ammonia levels were measured.Fifty patients completed the study. No statistical significance with regard to symptoms of mucositis was found. Fewer children receiving glutamine required parenteral nutrition (P=0.049), and the duration of parenteral nutrition was less (P=0.023). No adverse effects attributed to taking the glutamine were observed.The study showed that high-dose enteral glutamine did not reduce the incidence and severity of oral mucositis as determined by subjective toxicity measurements, but did show a significant reduction in parenteral nutrition usage. No adverse cumulative effect of this oral glutamine dose was observed.

Impact on module performance of spectral irradiance variation has been determined for III–V multijunctions compared against the four most common flat-plate module types (cadmium telluride, multicrystalline silicon, copper indium gallium selenide, and monocrystalline silicon. Hour-by-hour representative spectra were generated using atmospheric variables for Albuquerque, New Mexico, USA. Convolution with published values for external quantum efficiency gave the predicted current output. When combined with specifications of commercial PV modules, energy yield and revenue were predicted. This approach provides a means for optimizing PV module design based on various site-specific temporal variables.

The mechanisms underlying menopausal hot flushes are poorly understood, although it is generally assumed they result from disturbances of thermoregulatory centres in the hypothalamus. 8-Prenylnaringenin (8-PN) has been identified as a potent phytoestrogen in hops (Humulus lupulus) and there are claims that hop-containing preparations can reduce hot flushes. We have investigated the site of action of 8-PN in a rat model of menopausal hot flushes, in which the tail skin temperature (TST) is increased after oestrogen withdrawal induced by ovariectomy. Daily s.c. administration of either 17β-oestradiol (E2; 4 μg/kg) or 8-PN (400 μg/kg) significantly reduced the elevated TST after 2 days of treatment. Subcutaneous co-administration of either E2 or 8-PN with the oestrogen receptor (ER) antagonist, ICI 182,780 (200 μg/kg), which is thought not to cross the blood–brain barrier, completely blocked the effect of E2 and 8-PN on TST. The ERα- and ERβ-specific agonists, 4,4′,4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (100 μg/kg) and 2,3-bis(4-hydroxyphenyl)-propionitrile (60 μg/kg) respectively, both significantly reversed the raised TST in ovariectomised rats. These observations suggest that the regulation of the vasomotor response by oestrogens and phytoestrogens is mediated, at least in part, by peripheral mechanisms involving both ERα and ERβ.

Background: In the context of post-transplant immunosuppression, cyclosporine A (CSA) is dose adjusted in accordance with whole blood drug monitoring. While currently available immunoassay systems primarily target the parent drug, cross-reactivity results in the detection of the major circulating CSA metabolites, though their contribution to both immunosuppression and toxicity remain unclear. This study examines the relationship of CSA metabolites to hepatic and renal dysfunction and the incidence of graft-versus-host disease (GvHD) through parallel assaying of parent drug and drug/metabolites expressed as a metabolite ratio (Cp:mR). Method: Sequential pre-treatment (trough) whole blood samples ( n = 527) were collected from 31 allo-stem cell transplantation (SCT) recipients. Both parent drug and drug/metabolite levels were determined using the Abbott fluorescence polarization immunoassay. Results: The average mean Cp:mR was significantly higher in patients with hepatic ( P = 0.004) and renal dysfunction ( P = 0.004) than in those without. Significantly higher Cp:mR were also found in patients with grades II-IV GvHD ( P = 0.001) than were observed in patients who did not experience significant GvHD. When measured prospectively, an increasing Cp:mR predated the rise in serum creatinine concentration by a median of two weeks. Conclusions: This study demonstrates a clinically useful CSA metabolite ratio that shows association with hepatic and renal dysfunction and with GvHD. The measure can be used to predict those patients on CSA therapy who are likely to develop renal dysfunction.

Corticotrophin-releasing factor (CRF) plays a pivotal role in stress-induced suppression of the gonadotrophin-releasing hormone pulse generator. We have previously shown that type 2 CRF receptors (CRF(2)) mediate restraint stress-induced suppression of luteinising hormone (LH) pulses in the rat. The present study aimed: (i) to determine whether type 1 CRF receptors (CRF(1)) are also involved in this response to restraint and (ii) to investigate the differential involvement of CRF(1) and CRF(2) in the suppression of LH pulses in response to the metabolic perturbation of insulin-induced hypoglycemia and the innate immunological challenge of lipopolysaccharide (LPS). Ovariectomised rats with oestrogen replacement were implanted with intracerebroventricular (i.c.v.) and intravenous (i.v.) cannulae. Blood samples (25 microl) were collected every 5 min for 5 h for LH measurement. After 2 h of controlled blood sampling, rats were either exposed to restraint (1 h) or injected intravenously with insulin (0.25 IU/kg) or LPS (5 microg/kg). All three stressors suppressed LH pulses. The CRF(1) antagonist SSR125543Q (11.5 micromol/rat i.v., 30 min before stressor) blocked the inhibitory response to restraint, but not hypoglycaemia or LPS stress. In addition to its effect on restraint, the CRF(2) antagonist astressin(2)-B (28 nmol/rat i.c.v., 10 min before insulin or LPS) blocked hypoglycaemia or LPS stress-induced suppression of LH pulses. These results suggest that hypoglycaemia and LPS stress-induced LH suppression involves activation of CRF(2) while restraint stress-induced inhibition of LH pulses involves both CRF(1) and CRF(2).

This paper describes the development of a new mobile laboratory for the determination of the fine particle and gaseous emissions from a class 8 diesel tractor—trailer research vehicle. The new laboratory [Diesel Emissions Aerosol Laboratory (DEAL)] incorporates plumesampling capabilities which were based on a detailed flow field analysis using a combination of computational fluid dynamics modelling, flow visualization using smoke, streamers, and oil spots, and tracer gas measurements the results of which are described in the paper. The DEAL incorporates the unique ability to measure concurrently both the plume and the vehicular background which is generally not found in other on-road facilities.

A multi-phase instrument comparison study was conducted on two different diesel engines on a dynamometer to compare commonly used particulate matter (PM) measurement techniques while sampling the same diesel exhaust aerosol and to evaluate inter- and intra-method variability. Included in this evaluation were a Tapered Element Oscillating Microbalance (TEOM), three Scanning Mobility Particle Sizers (SMPSs), a Condensation Particle Counter (CPC), a TSI DustTrak, a MET-One E-BAM, and two Electrical Low Pressure Impactors (ELPIs) as well as two types of time-integrated filter samplers. Of the five on-line analyzers evaluated for PM mass concentration, the TEOM was shown to have the best overall correlation to the gravimetric filter method. For measuring concentration by particle number, the two ELPIs and the Model 3936L25 SMPS provided generally comparable results during both test phases (data for the stand-alone CPC were invalidated). With respect to measuring particle size distribution (PSD) by gravimetric analysis, the ELPIs were not found to be useful for a variety of reasons whereas for differential number distribution, the SMPSs and ELPIs provided generally comparable results.

Calcitonin gene-related peptide (CGRP) is involved in a variety of stress responses in the rat. Central administration of CGRP activates the hypothalamo–pituitary–adrenal axis resulting in increased corticosterone secretion. We have previously shown that central CGRP suppresses the gonadotrophin-releasing hormone (GnRH) pulse generator, specifically LH pulses. Endogenous opioid peptides (EOPs) have been shown to play an important role in stress-induced suppression of the reproductive axis. The aim of the present study was to test the hypothesis that EOPs mediate CGRP-induced suppression of pulsatile LH secretion. Ovariectomized rats were implanted with intracerebroventricular (i.c.v.) and i.v. cannulae. Intravenous administration of the opioid antagonist naloxone (250 μg) completely blocked the suppression of LH pulses induced by 1.5 μg i.c.v. CGRP and significantly attenuated the suppression of pulsatile LH secretion induced by 5 μg i.c.v. CGRP. Furthermore, intravenous administration of naloxone was found to immediately restore normal LH pulse frequency in animals treated 90 min earlier with 1.5 μg i.c.v. CGRP. Co-administration (i.c.v.) of CGRP (1.5 μg) with the μ and κ opioid receptor-specific antagonists naloxone (10 μg) and norbinaltorphimine (5 μg), respectively, blocked the CGRP-induced suppression of LH pulses, whilst i.c.v. co-administration of CGRP (1.5 μg) with the δ opioid receptor-specific antagonist naltrindole (5 μg) did not. These data provide evidence that EOPs play a pivotal role in mediating the inhibitory effects of CGRP on pulsatile LH secretion in the rat. They also suggest that the μ and κ, but not the δ, opioid receptors may be responsible for mediating the effects of CGRP on LH pulses.

Recent advances in Spectrolab's high efficiency III-V multi-junction space solar cells are reported. The latest generation GaInP/GaAs/Ge solar cells under production-the Ultra Triple Junction (UTJ)-have an average efficiency at maximum power of 28.0% (AMO, 28°C, 135.3 m W/cm 2 ) at beginning of life (BOL), and 22.6% at 60°C at end of life (EOL, 15 years in GEO orbit). This represents a 5.5% relative higher efficiency at EOL, compared with the previous generation Improved Triple Junction (ITJ) cells. The P/P 0 -for 1 MeV electrons after 10 15 cm -2 fluence has also improved to 0.86, compared with 0.84 for the ITJ cells. These and other performance results of UTJ solar cells are reviewed in comparison with ITJ solar cells.

In this paper, the inversion processing of cascade impactor data to construe continuous size distributions within fine particulate matter ( PM 2.5 ) is examined for residential oil furnace and fireplace appliance emissions. Impactor data from tests with these emissions sources are selected for the challenges they pose to comprehending the size distributions of aerosol mass and chemical species. In specific, the oil furnace aerosol offers an opportunity to apply data inversion to study a bimodal lognormal distribution in which much of the aerosol mass is impactor-penetrating nanoparticles ( 30 nm ) . The fireplace emissions on the other hand cover the issue of a chemical size distribution, which is subject to particle loss and characterized by a single lognormal, accumulation mode peak. Computational steps relevant to the application of the data inversion are illustrated in detail. Evaluation of correlation coefficients ( ⩾ 0.992 ) indicates that the inversion model predictions fit the impactor data well. Simulations of systematic measurement error ( ± 10 % ) at each impactor stage are shown to have a negligible impact on the inversion results for test data. It is concluded that data inversion can be effective when (i) source emissions contain a portion of particles that falls outside the measurement range of cascade impactors, (ii) a mass size distribution of an individual species is determined without the knowledge of the total mass concentration for that species, or when (iii) losses in the particle charger system are significant.

Although the fugitive dust associated with construction mud/dirt carryout can represent a substantial portion of the particulate matter (PM) emissions inventory in nonattainment areas, it has not been well characterized by direct sampling methods. In this paper, a research program is described that directly determined both PM10 and PM2.5 (particlesor =10 and 2.5 microm in classical aerodynamic diameter, respectively) emission factors for mud/dirt carryout from a major construction project located in metropolitan Kansas City, MO. The program also assessed the contribution of automotive emissions to the total PM2.5 burden and determined the baseline emissions from the test road. As part of the study, both time-integrated and continuous exposure-profiling methods were used to assess the PM emissions, including particle size and elemental composition. This research resulted in overall PM10 and PM2.5 emission factors of 6 and 0.2 g/vehicle, respectively. Although PM10 is within the range of prior U.S. Environmental Protection Agency (EPA) guidance, the PM2.5 emission factor is far lower than previous estimates published by EPA. In addition, based on both the particle size and chemical data obtained in the study, a major portion of the PM2.5 emissions appears to be attributable to automotive exhaust from light-duty, gasoline-powered vehicles and not to the fugitive dust associated with reentrained mud/dirt carryout.

In February 2000, a detailed measurement campaign was conducted over a 9-day period within a mercury (Hg) cell chlor-alkali plant in the southeastern United States (US). The principal focus of this study was to determine the fugitive (non-ducted) airborne Hg emissions from the main production equipment located in the “cell building” during extended period operations, including maintenance events. Other Hg monitoring conducted in and around the plant also included surveys of process areas surrounding the cell building, measurement of Hg fluxes from soil and other exposed surfaces, and speciated Hg measurements of ambient air both “upwind” and “downwind” of the production area as well as the determination of Hg contained in output products and wastes. The study was a collaborative effort among scientists from the US Environmental Protection Agency, the US Department of Energy's Oak Ridge National Laboratory, and the University of Michigan. This paper provides a description of the facility, the rationale and design of the study, and an introduction to companion papers containing the observational data.

Low-temperature photon counting with gated mode quenching is demonstrated with separate absorption, charge, and multiplication avalanche photodiodes that have an In/sub 0.52/Al/sub 0.48/As multiplication layer. A minimum of ten dark counts per second and single-photon detection efficiency of 16% were achieved at 130 K.

In this work, a direct thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) method is implemented to determine the polycyclic aromatic hydrocarbon (PAH) composition ( MW =202 – 302 amu ) in size-segregated aerosols from residential wood combustion. Six combustion tests are performed with two commonly burned wood fuel species, Douglas-fir (Pseudotsuga sp.) and white oak (Quercus sp.). Atmospheric dilution and cooling of the aerosol plume are simulated in a newly designed wind tunnel, and the resulting aerosols are size classified with an electrical low-pressure impactor (ELPI). ELPI stage data speciated by TD/GC/MS were inverted and modeled using a log normal distribution function. Gravimetrically determined PM2.5 (fine particles with aerodynamic diameters [d a ] μm ) emission rates (2.3– 10.2 g/kg ) corroborate to matrix-corrected ELPI mass measurements of stages 1–8 (2.7– 11.8 g/kg ). Fuel moisture content linearly correlates (r2=0.986) to the PM2.5 mass geometric mean diameter (dg). Combustion efficiency (CO2/CO) and temperature, O2 levels, and gas dilution temperature affect particle size distributions; dg ranges from 313 to 662 nm , indicating an accumulation mode. Reconstruction and summation of inverted ELPI data allow for the quantification of 27 individual PAHs (and clusters of structural PAH isomers); PAHs characterize between 0.01 and 0.07 wt % of the PM2.5 mass. Benzo[a]pyrene predominates the PAH emissions. PAH size allocations (dg range =171 – 331 nm ) are out of phase with PM2.5 mass ones and shifted to finer da. Higher and lower MW PAHs preferentially segregate to fine and coarse da in that order. The ultrafine mode contains on average greater than 80% of the total measured particle number concentration. Values of dg for particulate matter surface area distributions are between 120 and 330 nm . For these tests, PAH mass and PM surface area linearly correlate (r2⩾0.913). Application of a simple function to consider adsorption and absorption mechanisms makes apparent that (a) surface and core compositions of PAH of identical MW groups vary with combustion and (b) preferential surface adsorption of lower MW PAH is possible.

Objective: The purpose of this study was to determine the most appropriate dose of oral glutamine to use in a further clinical study in paediatric oncology patients. Design: This was a phase I, pharmokinetic study. Setting: The study was carried out at The Yorkshire Regional Centre for Paediatric Oncology and Haematology, St James's University Hospital, Leeds, UK. Subjects: Thirteen patients undergoing treatment for paediatric malignancy participated in this study. All 13 completed the study. Interventions: The most appropriate dose was determined by patient acceptability and by plasma glutamine and ammonia levels measured at timed intervals after ingestion of a single glutamine dose. Results: Doses of 0.35, 0.5 and 0.65 g/kg were well tolerated with no untoward plasma glutamine and ammonia levels. One patient was recruited to a higher dose of 0.75 g/kg, but the plasma glutamine and ammonia levels peaked at 2601 and 155 µmol/l, respectively. The ammonia level was greater than the acceptable upper limit. It was difficult to disperse the glutamine adequately at this dose, resulting in the suspension being found to be unpalatable and therefore no further patients were recruited at this dose. Conclusion: It was concluded that 0.65 g/kg is a safe dose of glutamine to use in a clinical study in paediatric oncology patients. Sponsorship: Scientific Hospital Supplies UK Ltd provided the L-glutamine and financial help for the biochemical analysis.

Kisspeptin is a hypothalamic peptide hormone that plays a pivotal role in pubertal onset and reproductive function. Previous studies have examined hypothalamic kisspeptin mRNA expression, either through in situ hybridisation or real-time RT-PCR, as a means quantifying kisspeptin gene expression. However, mRNA expression levels are not always reflected in levels of the translated protein. Kisspeptin-immunoreactivity (IR) has been extensively examined using immunohistochemistry, enabling detection and localisation of kisspeptin perikaya in the arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV). However, quantification of kisspeptin-IR remains challenging. We developed a specific rodent radioimmunoassay assay (RIA) capable of detecting and quantifying kisspeptin-IR in rodent tissues. The RIA uses kisspeptin-10 as a standard and radioactive tracer, combined with a commercially available antibody raised to the kisspeptin-10 fragment. Adult female wistar rat brain samples were sectioned at 300 µm and the ARC and AVPV punch micro-dissected. Brain punches were homogenised in extraction buffer and assayed with rodent kisspeptin-RIA. In accord with the pattern of kisspeptin mRNA expression, kisspeptin-IR was detected in both the ARC (47.1±6.2 fmol/punch, mean±SEM n = 15) and AVPV (7.6±1.3 fmol/punch, mean±SEM n = 15). Kisspeptin-IR was also detectable in rat placenta (1.26±0.15 fmol/mg). Reverse phase high pressure liquid chromatography analysis showed that hypothalamic kisspeptin-IR had the same elution profile as a synthetic rodent kisspeptin standard. A specific rodent kisspeptin-RIA will allow accurate quantification of kisspeptin peptide levels within specific tissues in rodent experimental models.

Thermal-optical analysis (TOA) is a widely used technique that fractionates carbonaceous aerosol particles into organic and elemental carbon (OC and EC), or carbonate. Thermal sub-fractions of evolved OC and EC are also used for source identification and apportionment; thus, oven temperature accuracy during TOA analysis is essential. Evidence now indicates that the "actual" sample (filter) temperature and the temperature measured by the built-in oven thermocouple (or set-point temperature) can differ by as much as 50 °C. This difference can affect the OC-EC split point selection and consequently the OC and EC fraction and sub-fraction concentrations being reported, depending on the sample composition and in-use TOA method and instrument. The present study systematically investigates the influence of an oven temperature calibration procedure for TOA. A dual-optical carbon analyzer that simultaneously measures transmission and reflectance (TOT and TOR) is used, functioning under the conditions of both the NIOSH 5040 and IMPROVE protocols. Application of the oven calibration procedure to our dual optics instrument significantly changed NIOSH 5040 carbon fractions (OC and EC) and the IMPROVE OC fraction. In addition, the well-known OC-EC split difference between NIOSH and IMPROVE methods is even further perturbed following the instrument calibration. Further study is needed to determine if the wide-spread application of this oven temperature calibration procedure will indeed improve accuracy and our ability to compare among carbonaceous aerosol studies that use TOA.

As Al/sub x/Ga/sub 1-x/As alloys are increasingly used for microwave and millimeter wave power devices and circuits that work under high electric field intensities and junction temperatures; understanding the temperature dependence of impact ionization and related properties in this material system becomes more and more important. Measurements of the multiplication gain and noise of avalanche photodiodes (APDs) provide insight to the avalanche characteristics of semiconductors. Previously, we have reported the characteristics of GaAs and Al/sub 0.2/Ga/sub 0.8/As APD's at room temperature. In this paper, the gain and noise of a series of homojunction Al/sub x/Ga/sub 1-x/As APD's were investigated over a wide temperature range from 29/spl deg/C to 125/spl deg/C, and the temperature dependence of their ionization coefficients was extracted.