bluuebunny/crossref_metadata_2025 huggingface dataset:
Embryonic Stem Cells Cultured in Serum-Free Medium Acquire Bovine Apolipoprotein B-100 from Feeder Cell Layers and Serum Replacement Medium
Authors: Hisamatsu-Sakamoto Michiko , Sakamoto Norihisa , Rosenberg Amy S.
Published: October 2007

Previous studies have demonstrated that cell populations that are cultured with heterologous animal products can acquire xenoantigens, potentially limiting their clinical utility because of immune responses. Embryonic stem cells (ESCs) are an attractive source of multiple potential cellular therapies and are typically derived and routinely cultured on murine embryonic fibroblast (MEF) feeder cell layers in commercially available serum replacement (SR) medium or fetal calf serum (FCS)-containing medium. Recently, we found that a strong antibody response was generated in human subjects after the second infusion of therapeutic cells cultured in FCS-containing medium. This response was specific for bovine apolipoprotein B-100 (apoB-100), which is the major protein component of low-density lipoproteins (LDL) and which targets its binding to abundant low-density lipoprotein receptors on the cell surface, from which it is internalized. Here, we have shown that ESCs cultured on MEFs in SR medium acquired bovine apoB-100 from MEFs and from the SR medium as well. Our findings also suggest that bovine LDL are used as critical nutrients for ESC propagation.

Disclosure of potential conflicts of interest is found at the end of this article.
Fertility and spermatogenesis are altered in α1b-adrenergic receptor knockout male mice
Authors: Mhaouty-Kodja Sakina , Lozach Anne , Habert René , Tanneux Magali , Guigon Céline , Brailly-Tabard Sylvie , Maltier Jean-Paul , Legrand-Maltier Chantal
Published: October 2007

To examine whether norepinephrine, through activation of α1b-adrenergic receptor, regulates male fertility and testicular functions, we used α1b-adrenergic receptor knockout (α1b-AR-KO) mice. In the adult stage (3–8 months), 73% of the homozygous males were hypofertile with relatively preserved spermatogenesis. Of the remaining males, 27% exhibited a complete infertility with a drastic reduction in testicular weight and spermatogenesis defect with germ cells entering a cell death pathway at meiotic stage. In both phenotypes, circulating levels of testosterone were highly reduced (−55 and −81% in hypofertile and infertile males respectively versus wild-type males). Consequently, circulating levels of LH were significantly elevated in α1b-AR-KO infertile mice. When incubated in vitro, the whole testes from infertile KO mice released significantly lower levels of testosterone (−40%). This, together with the fact that the mean absolute volume of Leydig cells per testis was not changed, suggests a compromised steroidogenic capacity of Leydig cells in infertile animals. In addition, RNA in situ hybridization study indicated an apparent higher expression of inhibin α- and βB-subunits in Sertoli cells of infertile α1b-AR-KO mice. This was correlated with a higher intra-testicular content of inhibin B (+220% above wild-type mice). Using specific primers, mRNA encoding α1b-AR was localized in early spermatocytes of wild-type testes. Our results indicate, for the first time, that α 1b-AR signaling plays a critical role in the control of male fertility, spermatogenesis, and steroidogenic capacityof Leydig cells. It is thus hypothesized that the absence of α1b-AR alters either directly germ cells or indirectly Sertoli cell/Leydig cell communications in infertile α1b-AR-KO mice.
Lack of cross-desensitization between leptin and prolactin signaling pathways despite the induction of suppressor of cytokine signaling 3 and PTP-1B
Authors: Roy A F , Benomar Y , Bailleux V , Vacher C M , Aubourg A , Gertler A , Djiane J , Taouis M
Published: October 2007

Hyperprolactinemia and hyperleptinemia occur during gestation and lactation with marked hyperphagia associated with leptin resistance. Prolactin (PRL) induces the expression of orexigenic neuropeptide Y (NPY) through the activation of JAK-2/STAT-3 signaling pathway in hypothalamic paraventricular nucleus (PVN) leading to hyperphagia. PRL may also act through the inhibition of anorexigenic effect of leptin via induction of suppressor of cytokine signaling 3 (SOCS-3). This paper aimed to co-localize PRL (PRL-R) and leptin (ObRb) receptors in the hypothalamus of female rats and investigate the possible cross-desensitization between PRL-R and ObRb. We showed that: 1) PRL-R and ObRb are expressed in the PVN and co-localized in the same neurons; 2) in lactating females leptin failed to activate JAK-2/STAT-3 signaling pathway; 3) in Chinese Hamster Ovary (CHO) stably co-expressing PRL-R and ObRb, overexposure to PRL did not affect leptin signaling but totally abolished PRL-dependent STAT-5 phosphorylation. The overexposure to leptin produces similar results with strong alteration of leptin-dependent STAT-3 phosphorylation, whereas PRL-dependent STAT-5 was not affected; and 4) CHO-ObRb/PRL-R cells overexposure to leptin or PRL induces the expression of negative regulators SOCS-3 and PTP-1B. Thus, we conclude that these negative regulators affect specifically the inducer signaling pathway; for instance, SOCS-3 induced by PRL will affect PRL-R signaling but not ObRb signaling and vice versa. Finally, the lack of cross-desensitization between PURL-R and ObRb suggests that hyperphagia observed during gestation and lactation may be attributed to a direct effect of PRL on NPYexpression, and is most likely exacerbated by the physiological leptin resistance state.
Surface Energy Fluxes and Evapotranspiration of a Mango Orchard Grown in a Semiarid Environment
Authors: da Silva Vicente de Paulo Rodrigues , de Azevedo Pedro Vieira , da Silva Bernardo Barbosa
Published: October 2007

Data from field experiments conducted in the semiarid climatic conditions of northeast Brazil were used to investigate the energy flux relations and evapotranspiration (ET) of a mango (Mangifera indica L.) orchard. The Bowen ratio–energy balance method was applied during the 1998–1999 fruiting cycles to estimate the energy balance components of the mango orchard, while the FAO Penman–Monteith approach was used for determining the reference evapotranspiration (ETo). Results indicated that latent heat flux density (λE) could be obtained, with reasonable precision, as a function of measured net radiation flux density (Rn). The percentage of Rn used as λE was higher for the fruit growth and fruit maturation phenological stages, and lower for the flowering and fruit fall stages. For both field campaigns, λE was found to be the major component of energy balance, comprising >70% of the available energy. Soil heat flux was always the smaller component, comprising <8%. Daily mean value of ET was higher during the 1998 fruiting cycle than that observed in 1999. Inversely, the ET increased approximately 6% from the 1998 to 1999 fruiting cycle. These results may be used for planning and management of irrigation for mangos grown in similar environmental conditions.
Aerial Color Infrared Photography to Optimize In‐Season Nitrogen Fertilizer Recommendations in Winter Wheat
Authors: Sripada Ravi P. , Farrer Dianne C. , Weisz Randy , Heiniger Ronnie W. , White Jeffrey G.
Published: October 2007

Remote sensing in the form of aerial color infrared (CIR) photography has been shown to be a useful tool for in‐season N management in winter wheat (Triticum aestivum L.). The objectives of this study were (i) to develop a methodology for predicting in‐season optimum fertilizer N rates for winter wheat at growth stage (GS) 30 directly from aerial CIR photography and (ii) to quantify how the relationships between these optimum N rates and spectral indices respond to different levels of biomass of the wheat crop. Field studies were conducted for three winter wheat growing seasons (2002–2004) over a wide range of soil conditions across North Carolina using a split‐split plot randomized complete block design. Different planting date–seeding rate (PDSR) combinations were applied to create a range of biomass levels at GS 30. Different levels of N were applied at GS 25 (N25) to create a range of N supply and winter wheat radiance, and at GS 30 (N30) to measure grain yield response to N30. Aerial CIR photographs were obtained at each site at GS 30 before N applications. Significant biomass response to PDSR and yield response to N25 and N30 were observed. Optimum N30 ranged from 0 to 124 kg ha−1 with a mean of 55 kg ha−1. Better prediction of optimum N30 rates were obtained with spectral indices calculated relative to high‐N reference strips compared to absolute bands or spectral indices. Biomass measured at GS 30 influenced the strength of the relationship between optimum N30 and spectral indices. When the GS‐30 biomass was >1000 kg ha−1, the best predictor of optimum N30 (R2 = 0.85) was a quadratic model based on measured winter wheat radiance relative to mean radiance in the G band for the high N reference strip (Rel GS).
Performance of Site‐Specific Nutrient Management for Irrigated, Transplanted Rice in Northwest India
Authors: Khurana Harmandeep S. , Phillips Steven B. , Bijay‐Singh  , Dobermann Achim , Sidhu Ajmer S. , Yadvinder‐Singh  , Peng Shaobing
Published: October 2007

Like in other parts of Asia, irrigated, transplanted rice (Oryza sativaL.) yield increases in Punjab, India, have slowed down in recent years. Further yield increases are likely to occur in smaller increments through fine‐tuning of crop management mainly by accounting for the large spatial and temporal variation in soil characteristics. On‐farm experiments were conducted from 2002 to 2004 at 56 sites in six key irrigated rice‐wheat (Triticum aestivumL.) domains of Punjab to evaluate an approach for site‐specific nutrient management (SSNM). Field‐specific N–P–K applications were calculated by accounting for the indigenous nutrient supply, yield targets, and nutrient demand as a function of the interactions between N, P, and K. The performance of SSNM was tested for two rice crops. Compared with the current farmers' fertilizer practice (FFP), average grain yield increased from 5.1 to 6.0 Mg ha−1, while plant N, P, and K accumulations increased by 13 to 15%. The gross return above fertilizer cost (GRF) was about 14% greater with SSNM than with FFP. Improved timing and/or splitting of fertilizer N increased N recovery efficiency from 0.20 kg kg−1in FFP plots to 0.30 kg kg−1in SSNM plots. The agronomic N use efficiency was 83% greater with SSNM than with FFP. The year‐wise effect on all parameters was, however, nonsignificant. As defined in our study, SSNM has potential for improving yields and nutrient efficiency in irrigated, transplanted rice.
Potential for Using Sunn Hemp as a Source of Biomass and Nitrogen for the Piedmont and Coastal Plain Regions of the Southeastern USA
Authors: Schomberg Harry H. , Martini Nicole L. , Diaz‐Perez Juan C. , Phatak Sharad C. , Balkcom Kipling S. , Bhardwaj Harbans L.
Published: October 2007

The tropical legume sunn hemp (Crotalaria juncea L.) could be a valuable green manure/cover crop for vegetable producers in the southeastern USA because of its rapid growth and large N2 fixing ability. Planting and termination date effects on biomass and N accumulation are relatively unknown for the region, but would help producers manage sunn hemp between summer and winter cash crops. We determined sunn hemp biomass and N content at 30, 60, 90, and 120 days after planting (DAP) for four planting dates (mid‐April to mid‐July) at a Piedmont and a Coastal Plain location in Georgia. Maximum biomass at a given DAP was produced from May and June plantings in the Piedmont and from April and May plantings in the Coastal Plains. Maximum biomass and N ranged from 8.9 to 13.0 Mg ha−1 and 135 to 285 kg ha−1, respectively. An equation for estimating sunn hemp biomass as a linear function of cumulative degree days (CDD) and cumulative solar radiation (CSR) was verified with independent data from Alabama, Florida, and Virginia. A similar equation for estimating N content as a quadratic function of CSR was not as accurate but still might be useful. Sunn hemp can fit well into short‐rotation sustainable vegetable production systems in the Southeast, and these equations can be used by producers to make reliable estimates of sunn hemp biomass production.
Response of Cultivars of Race Durango to Continual Dry Bean Versus Rotational Production Systems
Authors: Hayes Richard , Singh Shree P.
Published: October 2007

Continual dry bean (CB, Phaseolus vulgaris L.) production in the same field for 2 or more consecutive years is common worldwide. However, the effects on and performance of dry bean cultivars in the CB production system is not known. The objectives of this research were to (i) determine effects of the CB production system on seed yield, seed weight, and days to maturity of race Durango cultivars; (ii) determine the correlations for those three traits between the CB and rotational production (RP) systems; and (iii) identify superior cultivars within and across both production systems. Medium‐sized (25–40 g 100 seed−1) cultivars of great northern (8), pink (3), pinto (9), and red (5) of race Durango released between 1932 and 1998 were evaluated from 1999 to 2001 in a field that had been under 50 yr of CB production at the University of Idaho, Kimberly Research and Extension Center. Concurrently, they were evaluated under the standard RP system. The cultivar effects and cultivar × year interaction effects were significant (P < 0.01) for seed yield, seed weight, and days to maturity in both production systems. Continual dry bean production reduced mean seed yield by 68%, seed weight by 11%, and days to maturity by 6 d. Large differences among cultivars existed within and between market classes in both production systems. On average, great northern and pinto cultivars had the greatest reduction (71%) and pink (56%) followed by red (66%) cultivars had the least reduction in seed yield due to CB production. Cultivars UI 537, UI 239, Viva, and Harold had the highest levels of resistance to CB production. Despite significant (P < 0.01) positive phenotypic correlation between the two production systems for seed yield (r2 = 0.70), seed weight (r2 = 0.90), and days to maturity (r2 = 0.67), testing of dry bean cultivars using both production systems is suggested for identification of superior cultivars to be grown either within or across production systems.
Net Biome Productivity of Irrigated and Rainfed Maize–Soybean Rotations: Modeling vs. Measurements
Authors: Grant R. F. , Arkebauer T. J. , Dobermann A. , Hubbard K. G. , Schimelfenig T. T. , Suyker A. E. , Verma S. B. , Walters D. T.
Published: October 2007

Estimates of agricultural C sequestration require an understanding of how net ecosystem productivity (NEP) and net biome productivity (NBP) are affected by land use. Such estimates will most likely be made using mathematical models that have undergone well‐constrained tests against field measurements of CO2 exchange as affected by management. We tested a hydraulically driven soil–plant–atmosphere C and water transfer scheme in ecosys against CO2 and energy exchange measured by eddy covariance (EC) over irrigated and rainfed no‐till maize–soybean rotations at Mead, NE. Correlations between modeled and measured fluxes (R2 > 0.8) indicated that <20% of variation in EC fluxes could not be explained by the model. Annual aggregations of modeled fluxes indicated that NEP of irrigated and rainfed soybean in 2002 was −30 and −9 g C m−2 yr−1 (net C source) while NEP of irrigated and rainfed maize in 2003 was 615 and 397 g C m−2 yr−1 (net C sink). These NEPs were within the range of uncertainty in annual NEP estimated from gap‐filled EC fluxes. When grain harvests were subtracted from NEP to calculate NBP, both the modeled and measured maize–soybean rotations became net C sources of 40 to 80 g C m−2 yr−1 during 2002 and 2003. Long‐term model runs (100 yr) under repeated 2001–2004 weather sequences indicated that a rainfed no‐till maize–soybean rotation at Mead would lose about 30 g C m−2 yr−1. Irrigating this rotation would raise SOC by an average of 6 g C m−2 yr−1 over rainfed values. Modeled and measured results indicated only limited opportunity for long‐term soil C storage in irrigated or rainfed maize–soybean rotations under the soil, climate, and management typical of intensive crop production in the U.S. Midwest.
Analysis of Scaling‐Up Resistances from Leaf to Canopy Using Numerical Simulations
Authors: Furon Adriana C. , Warland Jon S. , Wagner‐Riddle Claudia
Published: October 2007

A multi‐layer model, combining Lagrangian dispersion at the canopy level with Ohm's Law analogy at the leaf level, was used in numerical simulations to assess the leaf‐to‐canopy scale translation of surface resistances. The model produced unique profiles of fluxes and scalar concentrations that satisfied both the dispersion and leaf models. Environmental factors and canopy architecture were varied, and stomatal conductance was simulated using either a simple relationship with net radiation or the Ball and Berry model to account for feedback mechanisms. Results showed that, when the assumptions of the Penman–Monteith equation were met, scaled‐up leaf conductance closely matched the bulk canopy conductance. However, as the scenarios modeled departed from the ideal conditions of Penman–Monteith, the agreement decreased. In particular, correct estimation of the aerodynamic resistance, through correct parameterization of the roughness length for sensible heat, was identified as a key issue.
Reduction of High Soil Test Phosphorus by Bermudagrass and Ryegrass–Bermudagrass following the Cessation of Broiler Litter Applications
Authors: Read J. J. , Sistani K. R. , Brink G. E. , Oldham J. L.
Published: October 2007

Factors that contribute to high soil P in bermudagrass [Cynodon dactylon L. (Pers.)] pastures include continued use of broiler litter rich in P to meet forage N requirements and removal of hay in summer only. This study determined if harvesting annual ryegrass (Lolium multiflorum Lam.) in addition to bermudagrass would reduce surplus soil P, Cu, and Zn faster than bermudagrass alone after litter application ceased on a Ruston soil (fine‐loamy, siliceaous, semiactive, thermic Typic Paleudults). During a 3‐yr build‐up, ‘Coastal’ bermudagrass was fertilized with 0, 4.5, 9, 18, and 36 Mg ha−1 litter yr−1 During the drawdown phase, plots were split and half was overseeded with ryegrass in fall 2001, 2002, and 2003. Whole plots were fertilized with NH4NO3 in spring–summer to provide 268 kg ha−1 N yr−1. Forage yield and P uptake increased as antecedent litter rate increased, and were greater in ryegrass–bermudagrass than bermudagrass in 2002, but not 2003. At 9 Mg ha−1 litter, harvesting ryegrass in addition to bermudagrass increased P uptake by 10 to 55%, depending on study year. During the drawdown phase, soil Mehlich‐3 P (M3P) and water‐extractable P to 15‐cm depth decreased by as much as 50 and 70%, respectively. Soils analysis within each sampling date found no significant effect of forage system or its interaction with litter rate. Data for 9 Mg ha−1 litter rate indicated 2 yr of forage P removal decreased residual M3P to an acceptable agronomic level (<70 mg kg−1). The potential to decrease surplus soil P by ryegrass–bermudagrass hay harvests was greatest when rainfall was inadequate for optimum bermudagrass yield.
Morphological, Anatomical, and Physiological Changes of Orchardgrass Leaves Grown under Fluctuating Light Regimes
Authors: Peri Pablo L. , Moot Derrick J. , Jarvis Peter , McNeil David L. , Lucas Richard J.
Published: October 2007

The physiological and anatomical adaptability of pastures growing under trees in silvopastoral systems can alter the efficiency of conversion of energy to dry matter (DM). This study was conducted to determine the effects of different fluctuating light regimes (from 24 to 100% transmissivity) on leaf physiology, morphology, anatomy, and structure of orchardgrass (Dactylis glomerata L.) in a silvopastoral experiment (New Zealand). Slatted shade structures created a bimodal light regime that represented an existing silvopastoral system. Morphologically, as transmissivity decreased the length of the youngest fully expanded leaf and pseudo‐stem height increased by up to 33% and the leaf width declined up to 22%. Physiologically, leaf adaptation to different light regimes was characterized by: (i) the light‐saturated rate of net photosynthesis (Pmax) and to less extent the photosynthetic efficiency (α) in sun conditions was double; (ii) in sunny conditions plants grown under shade were photosynthetically less efficient than plants grown in full sunlight with lower Pmax and α values; (iii) when plants were exposed to severe shade, leaves adapted to severe shade condition had the highest Pmax, α, and θ, and saturated at the minimum photosynthetic photon flux density (PPFD) value. These changes in leaf photosynthesis characteristics under different light regimes were attributed to anatomical changes that caused reductions in stomatal conductance (gs), the mesophyll surface area/leaf surface area ratio (Ames/A) and maintenance respiration for shade adapted plants. These photosynthetic responses and leaf adaptations to fluctuating light regimes can be included into a canopy photosynthesis model to improve the accuracy of DM predictions in silvopastoral systems.
Irrigated, No‐Till Corn and Barley Response to Nitrogen in Northern Colorado
Authors: Halvorson Ardell D. , Reule Curtis A.
Published: October 2007

Converting irrigated, conventional‐till (CT) systems to no‐till (NT) production systems can potentially reduce soil erosion, fossil fuel consumption, and greenhouse gas emissions. Nitrogen fertilization effects on irrigated corn (Zea mays L.) and malting barley (Hordeum distichon L.) yields in a corn‐barley rotation were evaluated for 6 yr on a clay loam soil to determine the viability of using a NT system and N needs for optimum crop yield. Six N treatments were established with N rates varying from 0 to 224 kg N ha−1 for corn and 0 to 112 kg N ha−1 for barley. Corn and barley grain yields were significantly increased by N fertilization each of 3 yr in the rotation. Three year average corn grain yields were near maximum with an available N (AN) (soil + fertilizer + irrigation water N) level of 274 kg N ha−1 Barley yields increased linearly with increasing N rate with grain protein content near 130 kg protein Mg−1 grain at the highest N rate. Nitrogen use efficiency (NUE) by corn and barley, based on grain N removal, decreased with increasing AN level and ranged from 204 to 39 and 68 to 31 kg grain kg−1 AN for the low and high N treatments for corn and barley, respectively. Total plant N uptake required to produce one Mg grain at near maximum yield in this study averaged 21 kg N for corn and 27 kg N for barley. Corn and barley residue production increased with increasing N rate. Irrigated, NT corn yields obtained in this corn‐barley rotation were acceptable (>10 Mg ha−1) for northern Colorado; however, barley yields did not meet our expected yield goal of 5.4 Mg ha−1 with the N rates used in this study, but grain protein was near maximum for malting barley. An irrigated, NT corn‐barley production system appears to be feasible in northern Colorado.
Crop Productivity and Economics during the Transition to Alternative Cropping Systems
Authors: Archer David W. , Jaradat Abdullah A. , Johnson Jane M‐F. , Weyers Sharon Lachnicht , Gesch Russ W. , Forcella Frank , Kludze Hillarius K.
Published: October 2007

Many environmental benefits accrue from reducing tillage and increasing crop diversity; however, economic factors often encourage the continued use of intensive tillage and specialized crop production. This study examined crop yields, input costs, and economic returns during the transition to a range of cropping system alternatives in the northern Corn Belt region, including different system (organic, conventional), tillage (conventional, strip‐tillage), rotation (corn–soybean, corn–soybean–wheat/alfalfa–alfalfa) [Zea mays L., Glycine max (L.) Merr., Triticum aestivum L., Medicago sativa L.], and fertility (no fertilizer/manure, fertilizer/manure applied at recommended rates) treatments. Increasing crop diversity and reducing tillage intensity reduced total costs by $24–102 ha−1 within conventional treatments, and $16–107 ha−1 within organic treatments. Yields of corn, soybean, and wheat were more than 15% lower when using organic vs. the highest yielding conventional practices. Treatments receiving fertilizer or manure had wheat yields more than 0.3 Mg ha−1 and alfalfa yields 2.7 Mg ha−1 higher than treatments that did not receive fertilizer or manure. Within conventional systems, no significant differences in the 4‐yr net present value of net returns were detected for tillage and rotation alternatives. Net present values for the organic systems without organic price premiums were at least $692 ha−1 lower than for the best conventional systems suggesting a barrier to the adoption of these systems should organic price premiums decline. However, when organic price premiums were included, most organic treatments had net present values comparable to or exceeding those from conventional treatments.
Effect of Tillage and Nitrogen Rate on Corn Yield and Nitrogen and Phosphorus Uptake in a Corn‐Soybean Rotation
Authors: Al‐Kaisi Mahdi , Kwaw‐Mensah David
Published: October 2007

Understanding tillage, N, and P interactions can contribute to improved N and P utilization and crop response. This study examined the interaction effects of tillage and N rate of two N sources on N and P uptake by corn (Zea maysL.). The study was conducted on Kenyon loam (fine loamy, mixed, mesic Typic Hapludolls) soil at the Iowa State University Northeast Research and Demonstration Farm near Nashua, IA. A randomized complete block design with a split‐plot arrangement in three replications was used for the two separate N source experiments. The tillage systems consist of no‐tillage (NT), strip‐tillage (ST), and chisel plow (CP) as main plots. Within each tillage four N rates (0, 85, 170, and 250 kg N ha−1) were assigned as subplots for each N source of manure (total N) and fertilizer (anhydrous ammonia) in a corn‐soybean [Glycine max(L.) Merr.] rotation. Tillage and increase in N rate beyond 85 kg ha−1had no effect on corn grain yield with both N sources. Tillage × N rate had a significant effect on plant N and P uptake, especially at early growth stages with both N sources. Recovery percentage of applied N across all tillage systems and N rates was 40% and 27% for manure and fertilizer sources, respectively, at the 12th‐leaf growth stage of corn (V12). Plant N and P uptake at V12 growth stage was 44% and 37%, respectively, across tillage systems, N sources, and N rates. The findings indicate that the N rate and seasonal variability have more influence on plant N and P uptake than does the tillage system.
Rhizoma Peanut Yield and Nutritive Value are Influenced by Harvest Technique and Timing
Authors: Butler Twain J. , Muir James P. , Islam M. Anowarul , Bow John R.
Published: October 2007

Rhizoma peanut (Arachis glabrata Benth.) is a warm‐season perennial forage legume adapted to the southern USA. The objectives of this study were to evaluate harvest technique and timing on dry matter (DM) yield, crude protein (CP), acid detergent fiber (ADF), and acid detergent lignin (ADL) concentrations of rhizoma peanut. Two experiments (one without irrigation and one with irrigation) each with four replications were conducted during the 2004–2006 growing seasons (April–October) in north‐central Texas on a Windthorst fine sandy loam. Treatments consisted of manually clipping all plant material three times throughout the growing season at 5‐cm height with a July rest (5‐JR) or a September rest (5‐SR), four times throughout the season (June, July, September, October) at 10‐cm height, or manual harvesting (hand‐plucking) all leaves and growing tips to ground level four times throughout the season. Annual rhizoma peanut DM yield for the irrigated experiment (4710 to 10870 kg DM ha−1) was greater than the nonirrigated experiment (2750 to 9300 kg ha−1). In both experiments, the 5‐JR treatment reduced rhizoma peanut DM yield in the third year by 29 to 37% compared with the hand‐plucked and the 5‐SR treatments. Harvest timing or technique did affect nutritive value although these differences were small, ranging from 186 to 204 g CP kg−1, 280 to 313 g ADF kg−1, and 57 to 65 g ADL kg−1. These data indicate that rhizoma peanut had high nutritive value regardless of treatment and maintained greater DM yield if harvested by hand‐plucking or at a 5‐cm height with a September rest.
Welcome to College? Developing a Richer Understanding of the Transition Process for Adult First Year Students Using Reflective Written Journals
Authors: Risquez Angelica , Moore Sarah , Morley Michael
Published: October 2007

This study investigates the process of adjustment among adult learners by focusing on their own perceptions as they make the transition to higher education in an Irish setting, in order to gain a richer understanding about early university experience. The analysis of the journal-based reflections confirms existing insights about the complexity of the adjustment process, emphasizing that adult students seem to face particular challenges and opportunities that may not prevail among their younger counterparts. The data provides a more personal and subjective picture of adjustment issues than has typically been available to date. The benefits of keeping and using insights from reflective journals are explored and in conclusion a “V-curve” model of mature student adjustment is proposed that suggests a more extreme form of the long established “U-curve” theory derived from organizational literature on adjustment.
Proportional Hazards Models of Graduation
Authors: Chimka Justin R. , Reed-Rhoads Teri , Barker Kash
Published: October 2007

Survival analysis is a statistical tool used to describe the duration between events. Many processes in medical research, engineering, and economics can be described using survival analysis techniques. This research involves studying engineering college student graduation using Cox proportional hazards models. Among male students with American College Test (ACT) scores only, those with better Science ACT scores were more likely to graduate. Among students submitting only Scholastic Assessment Test (SAT) scores upon application, controlling for other descriptors such as in-state residence, hometown population, and student major, students with better SAT Math score and female students were more likely to graduate. In summary, results reported here are the significance of standardized math test scores, gender, and Science ACT scores in explaining variation in student graduation under different conditions.
Rigorous modelling and optimization of hybrid separation processes based on pervaporation
Authors: Koczka Katalin , Mizsey Peter , Fonyo Zsolt
Published: October 2007

Hybrid separation processes are becoming more and more important in the practice if membrane technologies are also involved. In this work, a systematic investigation is completed for three sequence alternatives of distillation and pervaporation. These are the following: pervaporation followed with distillation (PV+D), distillation followed with pervaporation (D+PV), two distillation columns and a pervaporation unit between them (D+PV+D). The hybrid separation process alternatives are evaluated with rigorous modelling tools, but first, a rigorous simulation algorithm is determined for the pervaporation. The three hybrid separation processes are rigorously modelled with CHEMCAD, and optimized with the dynamic programming optimization method for the case of the separation of ethanol-water mixture. The objective function is the total annual cost (TAC). The energy consumption is also investigated. The selection of the ethanol-water mixture has two motivations: (i) it is quite often studied and well known, and (ii) to make biofuel (ethanol) production more economical, membrane technologies might also be applied. The results are compared with each other and with the classical separation completed with heteroazeotropic distillation. The optimized TAC shows that the distillation column followed with pervaporation is the most economical hybrid separation process alternative. Its TAC is about 66% of that of the classical separation.
Energy up-conversion in dilute polyfluorene solutions
Authors: Kuehne Alexander , Mackintosh Allan , Armstrong David , Pethrick Richard
Published: October 2007

Poly(9,9-dioctylfluorene) (PFO) shows highly efficient blue emission with photo excitation occurring between 340–400 nm. Here we show that PFO can in dilute solution emit at a wavelength well below that at which it is being exited. This, we propose is related to an energy transfer from conjugated parts of the polymer chain into more localised states which then emit at a lower wavelength. These localised states can be considered as defects in the conjugation of the polymer or as chain ends. These may produce quasi monomer or quasi dimer species within the chain, which will have a HOMO-LUMO gap of higher energy than the conjugated polymer. These then fluoresce at the lower wavelength; essentially causing, by energy transfer, a process of energy up-conversion.
New alternatives for erythropoietin therapy in chronic renal failure
Authors: Stoian Irina , Manolescu Bogdan , Atanasiu Valeriu , Lupescu Olivera
Published: October 2007

Erythropoietin (EPO) is one of the main cytokines involved in the regulation of erythropoiesis. The main site of EPO production are the kidneys. An altered EPO production leads to pathological conditions such as anemia and polycythaemia. Due to the progressive loss of renal peritubular cells, patients with chronic kidney disease (CKD) have low EPO plasma levels. This decreases erythron stimulation with the direct consequence of developing anemia. Before the introduction in the clinical practice of rHuEpo, in the late 1980s, the only solution for treating this type of anemia were blood transfusions and anabolic steroids. Even rHuEpo has proven to be safe and effective for treatment of anemias, there are some concerns about its cost, the need for frequent parenteral administration, and development of anti-EPO antibodies. These inconveniences prompted the search for novel erythropoiesis stimulating agents. Different strategies lead to isolation or chemical synthesis of such agents as darbepoetin alfa and EPO mimetics. In this review, we present some general aspects of EPO biology, with emphasis on chronic renal failure, and expose some of the alternatives to EPO used for anemia correction.
Current concepts and applications of computer navigation in orthopedic trauma surgery
Authors: Kendoff D. , Citak M. , Hüfner T. , Chaudhary S. , Krettek C.
Published: October 2007

Navigation has become widely integrated into regular endoprosthetic procedures, but clinical use of navigation systems in orthopaedic trauma has only been implemented in a few indications. Navigation systems enable an accuracy of 1 mm or 1 degree. Navigation can achieve higher precision when it is combined with different imaging modalities, including preoperative computer tomography (CT), intraoperative CT, two-dimensional fluoroscopy, and, recently, intraoperative three-dimensional fluoroscopy. The precision of the navigation system can be influenced by the surgeon as well as by the camera system, type of reference marker, and the registration process. Recent developments in orthopedic trauma navigation allow for bilateral femoral anteversion measurements, noninvasive registration of an uninjured thigh, and intraoperative three-dimensional fluoroscopy-based pedicle screw placement. Although the use of navigation has provided initial positive results in trauma care, prospective clinical studies remain to be performed.
Obese and female adolescents skip breakfast more than their non-obese and male peers
Authors: Rashidi Arash , Mohammadpour-Ahranjani Behnoush , Karandish Majid , Vafa Mohammad-Reza , Hajifaraji Majid , Ansari Farzaneh , Sadeghi Shima , Maddah Mohsen , Kalantari Nasser , Akhavi-Rad Mohammad-Bagher
Published: October 2007

We examined the association between overweight/gender and skipping breakfast among adolescent students in Tehran city using a cross-sectional study and a multistage random sampling method. All educational zones in Tehran city were covered during the educational year of 2000–01. In total, 2321 students aged 11–16 years (1068 male; 1263 female) participated in the study. Weight and height were measured and body mass index (BMI; kg/m2) was calculated. Overweight, pre-obesity and obesity were defined as BMI ≥ 85th, 85th to 95th, and ≥ 95th percentile of age-sex-specific BMI reference values, respectively. Self-reported frequency of breakfast consumption was categorized as usual/always, often, and rarely/never (5–7, 2–4 and 0–1 times/wk, respectively). Student’s t and Chi-square tests were employed to analyze the data. Statistical inferences were made at α = 0.05. In boys and girls, the mean ± standard deviation of BMI was 19.8 ± 4.0 and 20.6 ± 4.1 kg/m2, the 18.8% and 23.1% were overweight, and 7.3% and 8.3% were obese, respectively. There was a significant difference in the frequency of breakfast consumption between obese and normal male students (P < 0.001). Differences between pre-obese and normal, and obese and normal female students were also significant (P < 0.002 and P < 0.001, respectively). A significant difference was found in the frequency of breakfast consumption between male and female adolescents in all three categories (P < 0.001). These results suggest that obese and female adolescents are more likely to skip breakfast than their normal and male peers and are therefore at higher risk for growth deficits and low educational performance. Preventive/educational programs are urgently needed in this age group.
Transformation of the ownership structure in Polish healthcare and its effects
Authors: Tyszko Piotr , Wierzba Waldemar , Kanecki Krzysztof , Ziółkowska Anna
Published: October 2007

Poland, like other countries with previously dominant state healthcare systems, has introduced ownership transformation in the healthcare structure. These changes, however, are being accomplished without a clearly defined state policy in this area. The aim of the present study was to assess the course and effects of ownership transformation in outpatient healthcare and hospitals. Data were collected from publications of the Central Statistical Office, which provided information on the numbers of outpatient healthcare institutions, medical practices, general hospitals, and services they provided. The healthcare ownership transformation has divided the medical services market into public and nonpublic providers. In addition, privatization of outpatient healthcare facilities precedes privatization of hospitals, outpatient institutions providing primary healthcare were privatized first; the subsequent stage included those providing specialized services, at first privatization of ambulatory medical infrastructure preceded privatization of services in urban areas, whereas in rural areas, privatization of services preceded structural privatization, privatization provides favorable conditions to improve territorial availability of outpatient healthcare in urban areas, medical practices, although numerous, are of little importance in providing services, the hospital ownership transformation is at its initial stage, and structural ownership transformation in the Polish healthcare system is subject to market rules.
Influence of cadmium and copper on tissue element levels of pregnant rats
Authors: Turgut Sebahat , Enli Yaşar , Emmungil Gülten , Turgut Günfer , Demir Süleyman , Kaptanoglu Bünyamin , Genç Osman
Published: October 2007

In the current study, we examined the effects of Cd on Cd, Cu, Zn and Fe levels in placenta and maternal and fetal plasma and tissues, the placental weight, total fetal and maternal body weights, and fetal and maternal tissue weights during pregnancy. A total of 21 adult female rats were treated during gestation with drinking water containing one of the following: 70 mg/L of CdCl2, a combination of 70 mg/L of CdCl2 and 70 mg/L of CuSO4, or no addition (control). Placenta Cu and Fe levels, fetal liver and kidney Cu levels, and fetal liver tissue weights were lower in the group administered Cd than in the control group. Also, Cd levels in the placenta, maternal and fetal liver, and maternal kidney were higher in the group treated with Cd than in controls. In the group administered both Cd and Cu, fetal body and tissue weights did not change, but Cd levels in the placenta, maternal and fetal liver, and maternal kidneys were higher than in controls. Zn and Fe levels in the maternal kidney and fetal liver were also lower in this group. Cd exposure during pregnancy resulted in Cd accumulation in maternal and fetal tissues during pregnancy and a decrease in the total weight of fetuses, and the combination of Cd and Cu caused some changes in the both maternal and fetal levels of Cu, Zn, and Fe, but it did not cause changes in the total fetal body weight or the weights of individual tissues.
Numerical analysis of three-colour HgCdTe detectors
Authors: Jóźwikowski K. , Rogalski A.
Published: October 2007

The performance of three-colour HgCdTe photovoltaic heterostructure detector is examined theoretically. In comparison with two-colour detectors with two back-to-back junctions, three-colour structure contains an absorber of intermediate wavelength placed between two junctions and electronic barriers are used to isolate this intermediate region. This structure was first proposed by British workers.

Three-detector structures with different localizations of separating barriers are analyzed. The calculation results are presented in the form of spatial distributions of bandgap energy and quantum efficiency.

Enhanced original computer programs are applied to solve the system of non-linear continuity equations for carriers and Poisson equations. In addition, the numerical analysis includes the dependence of absorption coefficient on Burstein effect as well as interference effects in heterostructure with metallic electrical contacts.

It is shown that the performance of the detector is critically dependent on the barrier’s doping level and position in relation to the junction. This behaviour is serious disadvantage of the considered three-colour detector. A small shift of the barrier location and doping level causes serious changes in spectral responsivity.
Undetected Hangman's Fracture in a Patient Referred for Physical Therapy for the Treatment of Neck Pain Following Trauma
Authors: Ross Michael D , Cheeks John M
Published: October 2007

Background and Purpose

This case report describes a patient referred for physical therapy treatment of neck pain who had an underlying hangman's fracture that precluded physical therapy intervention.

Case Description

This case involved a 61-year-old man who had a sudden onset of neck pain after a motor vehicle accident 8 weeks before his initial physical therapy visit. Conventional radiographs of his cervical spine taken on the day of the accident did not reveal any abnormalities. Based on the findings at his initial physical therapy visit, the physical therapist ordered conventional radiographs of the cervical spine to rule out the possibility of an undetected fracture.

Outcomes

The radiographs revealed bilateral C2 pars interarticularis defects consistent with a hangman's fracture. The patient was referred to a neurosurgeon for immediate review. Based on a normal neurological examination, a relatively low level of pain, and the results of radiographic flexion and extension views of the cervical spine (which revealed no evidence of instability), the neurosurgeon recommended that the patient continue with nonsurgical management.

Discussion

In patients with neck pain caused by trauma, physical therapists should be alert for the presence of cervical spine fractures. Even if the initial radiographs are negative for a fracture, additional diagnostic imaging may be necessary for a small number of patients, because they may have undetected injuries that would necessitate medical referral and preclude physical therapy intervention.
Thermodynamic and Kinetic Aspects of the Reactions of Titanium(I) ion with the Sulfurtransfer Reagent SCO via the C22O Bond Activation Pathway
Authors: Yin Ping , Hu Yucai , Xu Yanbin , Zhang Jiang , Yu Zhongxi , Sun Lin , Bao Chongrong
Published: October 2007

Theoretical studies on the thermodynamic and kinetic aspects of the reactions of Ti+ ion with the sulfur-transfer reagent SCO via the C22O bond activation pathway have been carried out over the temperature range 200 — 1200K using the DFT=B3LYP method, general statistical thermodynamics and Eyring transition state theory with the Wigner correction. The relevant reactions comprise: reaction 1 [Formula: see text], and reaction 2 [Formula: see text] in which the spin multiplicity changes from the quartet state to the doublet state in the crossing region. It is concluded that the order of the equilibrium constants (K) and the reaction rate constants (k) are consistent with that of their corresponding exoergic energies DE and reaction barriers, respectively, and their differences at low temperature are larger than those at high temperature. Step 2 of reaction 1 is both thermodynamically and kinetically favoured over the entire temperature range. Moreover, both reactions 1 and 2 are exothermic and proceed spontaneously in which their entropy increases, and the magnitudes of their thermodynamic constants all decrease with rising temperature. The calculated DH8, DG8, and DS8 values of the two reactions are relatively similar. However, because reactants 4Ti+ and SCO have a lower energy than that of reactants 2Ti+ and SCO, it is reaction 2, in which the quartet state is changed to the doublet state through intersystem crossing, which should be seen as dominant.
Schizophrenia
Authors: Konopaske Glenn T , Lewis David A
Published: October 2007

Schizophrenia is a chronic psychiatric disorder characterized by psychotic symptoms and deterioration from previous levels of functioning; it may be a consequence of interactions between environmental factors and susceptibility genes. Treatment includes the combined use of antipsychotic medications and psychosocial therapy.
Long‐term Depression and Depotentiation
Authors: Lisman John , Richard Edwin A
Published: October 2007

Long‐term depression and depotentiation are activity‐dependent processes that weaken synapses. These processes are thought to work together with long‐term potentiation to encode memory.
Headache
Authors: Silberstein Stephen D
Published: October 2007

Headache is described as a throbbing, pulsating or dull ache, often worsened by movement and varying in intensity. Headache can be a disorder unto itself, such as migraine, or a symptom of another disorder ranging from a head injury to a brain tumour.
Algal Taxonomy: Historical Overview
Authors: Moestrup Øjvind
Published: October 2007

The taxonomy of algae since the time of Linnaeus are described here. The merging of the Algae and the Flagellata into a common group is explained, and the impact of electron microscopy and molecular biology, which has resulted in a much more precise circumscription of the different taxonomic groups of algae, is discussed.
Red Algae
Authors: Gurgel Carlos Frederico Deluqui , Lopez‐Bautista Juan
Published: October 2007

Red algae are ancient aquatic plants with simple organization, noteworthy colour variation, vast morphological plasticity, challenging taxonomy and most extant species (about 6000 worldwide) are marine. They include species with complex life cycles, significant ecological importance and extensive economical applications.
Hydrothermal Vent Communities
Authors: Canganella Francesco
Published: October 2007

Deep‐sea hydrothermal vents are hydrogeological phenomena occurring on the deep ocean bottom, wherever it is a tectonically active area and heated waters reach the seafloor with significant temperatures and pressures. Specific animal communities are strongly associated with these hydrothermal areas, and unique trophic relationships are established among chemolithotrophic bacteria, clams and mussels.