Scanning Capacitance Spectroscopy on n\u3csup\u3e+\u3c/sup\u3e-p Asymmetrical Junctions in Multicrystalline Si Solar Cells

We report on a scanning capacitance spectroscopy (SCS) study on the n+-p junction of multicrystalline silicon solar cells. We found that the spectra taken at space intervals of ∼10 nm exhibit characteristic features that depend strongly on the location relative to the junction. The capacitance-voltage spectra exhibit a local minimum capacitance value at the electrical junction, which allows the junction to be identified with ∼10-nm resolution. The spectra also show complicated transitions from the junction to the n-region with two local capacitance minima on the capacitance-voltage curves; similar spectra to that have not been previously reported in the literature. These distinctive spectra are due to uneven carrier-flow from both the n- and p-sides. Our results contribute significantly to the SCS study on asymmetrical junctions

The Effect of Basal Diet on Lactate-Producing Bacteria and the Susceptibility of Sheep to Lactic Acidosis

The influence of a diet of either pasture or hay on the development of lactic acidosis in sheep was investigated using a grain challenge approach. Twenty-four Merino wethers with a mean live weight of 36.7 (s.e. 3.6) kg were used; 12 were adapted to grass pasture and 12 to hay (lucerne and oaten hay, 60 : 40) for 4 weeks before being given 1 kg of crushed barley via stomach tube. Six sheep in each group were also given virginiamycin (VM; 50 mg/kg barley) with the grain to test the efficacy of this antibiotic in controlling the bacteria responsible for the development of acidosis. Changes in volatile fatty acid (VFA), pH, lactate and bacterial count in the rumen and faecal pH and dry matter (DM) were measured for a 24-h period following administration of the barley. Daily intakes of hay were measured for a 10-day period following grain engorgement. Total ruminal VFA increased (P < 0.01) over time and tended (P = 0.08) to be higher in sheep adapted to hay than in those adapted to pasture (67.5 v. 59.8 mmol/l). The molar proportions of VFA changed (P< 0.01) over time in favour of propionate in both groups. Ruminal pH was higher (P< 0.001) in pasture-adapted sheep, but declined (P< 0.001) in both groups over time following the introduction of barley. This decline in pH was associated with increases in ruminal concentration of VFA in pasture-adapted sheep and VFA and lactate in hay-adapted sheep. The addition of VM resulted in a higher (P < 0.001) proportion of propionate and a trend towards higher (P = 0.24) faecal pH and DM content. Faecal pH and DM content declined (P < 0.001) over time and was lower for the pasture-adapted sheep. The introduction of either barley alone or barley with VM from both hay and pasture diets increased (P < 0.05) the viable counts of total bacteria, Streptococcus bovis and lactic acid bacteria. Bacterial isolates were purified and identified by complete sequencing of the 16S rRNA gene to determine the predominant bacteria during the overfeeding of grain. Isolates from medium selective for S. bovis were all identified as this species when VM was not given. VM had no effect on counts of viable bacteria, but inhibited the growth of S. bovis

Effect of tail docking in Awassi lambs on metabolizable energy requirements and chemical composition of carcasses

The effect of tail docking on metabolizable energy requirements and carcass characteristics was studied using 80 weaned entire Awassi male lambs. Docking was performed within 3 days of birth and lambs were weaned at 90 days old. Docked and undocked lambs were randomly allocated to four groups, individually penned and offered different amounts of a pelleted concentrate diet. The pelleted diet was estimated to contain 11.8 MJ of metabolizable energy (ME) and 182 g of crude protein (CP) per kg dry matter (DM). Lambs on the high levels of intake were slaughtered at a target weight of approximately 45 kg. Other lambs were maintained on the diet for 149 days before being slaughtered. The right sides of all carcasses were cut into standardized commercial cuts then dissected into muscle, fat and bone. The soft tissue was pooled and analysed for DM, CP, ash and fat. Prediction of live-weight gain (LWG) and empty body gain for a given ME intake (MEI) was made using the growth and MEI data. MEI was expressed as MJ per kg metabolic body weight (M 0.75) per day. Tail docking had no effect (P> 0.05) on lamb growth from birth to weaning. During the post-weaning growth period, LWG and empty body gain were significantly higher (P 0.05) at high levels of intakes (between 0.74 and 1.1 MJ/kg M 0.75 per day). Hot and cold carcass weights were similar (P > 0.05) for the two groups. Differences in empty body weight and fleece-free empty body weight were significant (P 0.05) on food conversion efficiency (FCE). Carcasses from docked lambs had significantly lower (P 0.05) ash content

Secondary metabolites of marine-derived Bacillus spizizenii against the enteric redmouth disease in common carp, Cyprinus carpio

Looking for effective alternatives, such as secondary microbial metabolites, is needed to restrict the use of antibiotics in farmed fish and their detrimental effects on public health and the environment. Thirty-three water and sediments samples were collected from coastal areas in the Basrah Governorate, southern Iraq, to assess their biological activity against bacterial pathogens isolated from Cyprinus carpio, with enteric red mouth disease. 20 spore-forming bacteria were isolated and identified by VITEK BCL cards and amplifying the gyrA gene. Furthermore, the secondary metabolites produced by the strains were extracted and analyzed by GC-MS. Four pathogenic bacteria were isolated from common carp infected with the enteric red mouth disease. The antibacterial activity of the extracts of the isolated marine strains was examined on bacteria causing enteric red mouth disease and Y. ruckeri and P. aeruginosa. Based on the results, the marine isolates were identified as B. spizizenii and GC-MS analysis revealed that these strains' extract contained amino acids and their derivatives and esters and hydrocarbons. Also, biochemical identifications showed that the bacteria isolated from fish belonged to the species of Yersinia ruckeri, Aeromonas hydrophila, Streptococcus agalactiae, and Pseudomonas aeruginosa. According to the antibacterial activity assay, the extracts of B. spizizenii strains were considerably active against bacteria involved in enteric red mouth disease, especially Y. ruckeri. These findings indicate marine B. spizizenii can be replaced with antibiotics in the aquaculture industry to combat infections

Effects of selenium and vitamin E on performance, physiological response, and selenium balance in heat-stressed sheep

Forty-two 7-mo-old Australian Merino wethers were used in a 50-d trial to investigate the effects of Se and vitamin E on the performance and physiological responses of heat-stressed sheep. Sheep were exposed to thermoneutral conditions (maximum = 24°C and minimum = 20°C) for 28 d followed by heat (maximum = 38°C and minimum = 28°C) for 22 d. Hot conditions were imposed between 0700 and 1800 h. Sheep were randomly allocated to diets containing 0.8 mg/kg Se (Sel-Plex), 150 mg/kg vitamin E, or 0.8 mg/kg Se and 150 mg/kg vitamin E for either the duration of the study (50 d) or from d 1 of the hot period until the end of the study. A control group that received no supplemental Se and vitamin E for the duration of the study was included. Feed intake was measured daily and sheep were weighed weekly. Blood samples were collected from all sheep before feeding on d 1, 21, and 49 for measurement of biochemical and enzymatic variables. The concentration of Se was determined in offered and refused feed, feces, urine, water, plasma, liver, and kidneys. Exposure to heat reduced (P < 0.05) DMI by 11.9%, ADG by 198 g, serum concentration of urea nitrogen and Se by 17.8%, and plasma total antioxidant status by 26.4%. During hot conditions, sheep receiving Se and vitamin E supplements for 50 d had reduced (P < 0.05) BW loss and elevated G:F compared to control sheep. Serum Se concentration and the plasma total antioxidant status were greatest in sheep receiving Se and vitamin E supplements for 50 d (P < 0.05). These results indicate that dietary supplementation with Se and vitamin E reduces the adverse effects of a high heat load. Additional studies are warranted to elucidate the mechanisms responsible for these effects

Preliminary Study of Natural Alpha Particle Track Through Solid State Nuclear Track Detector, CR-39.

Measurements of alpha particle tracks parameters from 10B(n

In vitro biodegradation of hepatotoxic indospicine in Indigofera spicata and its degradation derivatives by camel foregut and cattle rumen fluids

The known accumulation of the hepatotoxin indospicine in tissues of camels and cattle grazing Indigofera pasture plants is unusual in that free amino acids would normally be expected to be degraded during the fermentation processes in these foregut fermenters. In this study, in vitro experiments were carried out to examine the degradability of indospicine of Indigofera spicata by camel and cattle foregut microbiota. In the first experiment, a 48 h in vitro incubation was carried out using foregut fluid samples that were collected from 15 feral camels and also a fistulated cow. Degradability of indospicine ranged between 97 − 99% with the higher value of 99% for camels. A pooled sample of foregut fluids from three camels that were on a roughage diet was used in a second experiment to examine the time-dependent degradation of indospicine present in the plant materials. Results indicated that camels’ foregut fluids have the ability to biodegrade approximately 99% of the indospicine in I. spicata within 48 h of incubation and produced 2-aminopimelamic acid and 2-aminopimelic acid. The time-dependent degradation analysis showed rapid indospicine degradation (65 nmol/h) during the first 8−18 h of incubation followed by a slower degradation rate (12 nmol/h) between 18 h and 48 h. Indospicine degradation products were also degraded towards the end of the experiment. The results of these in vitro degradation studies suggest that dietary indospicine may undergo extensive degradation in the foregut of the camel resulting in trace levels after 48 hours. The retention time for plant material in the camel foregut varies depending on feed quality, and the results of this study together with the observed accumulation of indospicine in camel tissues suggests that although indospicine can be degraded by foregut fermentation, this degradation is not complete before the passage of the digesta into the intestine

Effect of Concentrate Feeding on Milk Yield and Body-Weight Change of Awassi Ewes and the Growth of their Lambs

The response of Awassi ewes to graded amounts of supplementary concentrate diet was examined for the first 12 weeks of lactation. The growth rate of lambs and their health status were also investigated. Seventy-five ewes were divided into three equal groups and given a basal roughage diet of shredded wheat straw at a rate of 750 g dry matter (DM) per ewe per day supplemented with a concentrate diet at three months, 950 g (low), 1150 g (medium) and 1350 g (high) of DM per ewe per day starting at the beginning of lactation. Ewes were adapted to the diet by feeding daily at a rate of 200g per ewe during the last 6 weeks of pregnancy. The concentrate was estimated to contain 11.8 MJ of metabolizable energy and 182 g of crude protein per kg DM. Ewes and their offspring were housed in a partly enclosed yard. Lambs remained with their dams continuously except for the days of milk yield measurements, when they were separated from the dam for 11 or 12 h. The ewes examined for subclinical mastitis and the incidence of scouring in lambs was recorded. Ewes given the high level of concentrate produced more (

Profiling the Built-in Electrical Potential in III-V Multijunction Solar Cells: Preprint

We report on a direct measurement of the electrical potential on cross-sections of GaInP2/GaAs multiple-junction solar cells by using an ultrahigh-vacuum scanning Kelvin probe microscope (UHV-SKPM). The UHV-SKPM allows us to measure the potential without air molecules being adsorbed on the cross-sectional surface. Moreover, it uses a GaAs laser with photon energy of 1.4 eV for the atomic force microscope (AFM) operation. This eliminated the light-absorption-induced bottom-junction flattening and top-junction enhancement, which happened in our previous potential measurement using a 1.85-eV laser for the AFM operation. Three potentials were measured at the top, tunneling, and bottom junctions. Values of the potentials are smaller than the potentials in the bulk. This indicates that the Fermi level on the UHV-cleaved (110) surface was pinned, presumably due to defects upon cleaving. We also observed higher potentials at atomic steps than on the terraces for both GaInP2 epitaxial layer and GaAs substrate. Combining scanning tunneling microscopy (STM) and SKPM measurements, we found that the potential height at steps of the GaAs substrate depends on the step direction, which is probably a direct result of unbalanced cations and anions at the steps