bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alkalinity dynamics in an unacidified alpine lake, Sierra Nevada, California1
Authors: Stoddard John L. 
Published: April 2010

Gem Lake, a small, unacidified, high elevation lake in the Sierra Nevada, undergoes an annual cycle of low alkalinity (between 30 and 40 µcq liter−1) during the ice‐free season and high alkalinity (>240 µeq liter−1) in fall and winter. Both pH and alkalinity decrease drastically (up to one unit for pH and 200 µeq liter 1 for alkalinity) during spring snowmelt, but chemistry of the snow, snowmelt, and runoff indicate that the declines in alkalinity are due to dilution rather than acidification. The hydraulic residence time in the lake increases from about 135 d in winter to <7 d during snowmelt; high alkalinity water is simply flushed from the lake and replaced by water with an ionic composition very near that of the snowmelt runoff.Increases in alkalinity in fall and winter can be accounted for by the rates of weathering in the watershed. A mass balance approach is used to reconstruct weathering reactions in the basin; it suggests that the lake receives both surface runoff, with the weathering products of the hydrolysis of granodiorite minerals to kaolinite, and deep water from subterranean circulation, with the products of granodiorite weathering to both kaolinite and smectite. The relative importances of low alkalinity surface runoff and high alkalinity groundwater to the recharge of the lake are proposed as factors controlling the seasonal bicarbonate concentration of the lake.
Bacterioplankton in Lake Michigan: Dynamics, controls, and significance to carbon flux1
Authors: Scavia Donald , Laird Gwenyth A. 
Published: April 2010

Lake Michigan bacterial production, based on [3H‐methyl]thymidine (TdR) incorporation and empirically determined conversion factors (5–25 × 109 cells nmol−1), decreased with distance from shore (∼ 2 × over 30 km), was higher at night (1.4 × –2.2 ×), and decreased with depth (∼ 10 × over 100 m). TdR‐based growth rates were consistent with independent antibiotic‐ and dilution‐based estimates. Population size varied little and appeared controlled by balanced growth (0.02–0.33 h−1) and grazing (0.039–0.12 h−1). Growth correlated with temperature only below 10°C. Cell size ranged from 0.015 to 0.072 µm3. Carbon content averaged 0.154 ± 0.047 pg C µm−3. Net annual carbon production was 142 g C m−2 yr−1. Summer averages were 28.9 (epilimnion), 10.4 (10–35 m), 1.6 (hypolimnion) µg C liter− d−1, and 652 mg C m−2 d−1 for the water column. Flux to microconsumers averaged 8.4 µg C liter−1 d−1 in the summer epilimnion.Annual areal bacterial carbon demand is met by autotrophic production only if little of the latter is lost by other means. This suggests that external loads are needed, our conversion factors are high, or autotrophic production is underestimated. Although only small adjustments of those factors will satisfy the annual balance, the summer imbalance is still too large. We suggest that temporal and spatial disequilibrium of labile organic carbon supply and bacterial use is responsible for the apparent discrepancy during summer.
A comparison of four methods for determining planktonic community production1
Authors: Bender Michael , Grande Karen , Johnson Kenneth , Marra John , Williams Peter J. LeB. , Sieburth John , Pilson Michael , Langdon Chris , Hitchcock Gary , Orchardo Joseph , Hunt Carleton , Donaghay Percy , Heinemann Kristina 
Published: April 2010

Samples from two coastal experimental ecosystems were incubated in vitro and sampled over 24 h. Production rates were measured by the 14C method, the O2 and CO2 light‐dark bottle methods, and the18O method. O2 production in the experimental enclosures (volume ∼ 1.3 × 104 liters) was also measured directly.Photosynthetic and respiratory quotients were close to 1.0. Gross production values determined by O2 light‐dark experiments, CO2 light‐dark experiments, and 18O were similar. 14C production ranged from 60 to 100% of gross production measured in CO2 light‐dark experiments, indicating that 14C uptake is not precisely fixed with respect to other measures of community metabolism. There was no evidence that 14C or any other method underestimated the rate of primary production in vitro by more than 40%. Productivities in vitro ranged from 35 to 100% of those in the mesocosm at similar light intensities.In samples from one of the ecosystems, the rate of respiration in the light (calculated from 18O data) was an order of magnitude greater than the rate in the dark. This difference may be ascribed to either photorespiration or light enhancement of mitochondrial respiration.
Volumetric estimates of phytoplankton production in newly upwelled waters of the southern Benguela Current1
Authors: Olivieri Emilia T. , Hutchings Laurence 
Published: April 2010

Production, in terms of volume of particulate matter, was studied in four developing phytoplankton communities in newly upwelled waters of the southern Benguela Current. Growth (max doublings d−1 2.9, max C production ∼21 g m−2 d−1) of phytoplankton upwelled from source water was rapid, with little evidence of a lag phase. The growth pattern differed for each community encountered and was related to the rate of mixing of the water column and the nutrient and light regimes. Production rates were highest in newly upwelled waters and lowest under limiting light and during periods of nitrate depletion in the upper mixed layer. Changes in growth rates were also attributed to short‐term wind variations that caused water bodies to mix and change the nutrient regimes.Growth occurred over a wide size range of particles, mostly in the range 20–80‐µm equivalent spherical diameters (ESD), corresponding to chains of diatoms, but occasionally also in the range of 6–14‐µm ESD, suggesting some growth of small‐celled algae and microflagellates. A diel variation was observed, with volume increases during the day greatly exceeding those at night except under extreme limiting conditions when there was some growth in the dark.
Photosynthetic action, absorption, and quantum yield spectra for a natural population of Oscillatoria in the North Atlantic1
Authors: Lewis Marlon R. , Ulloa Osvaldo , Platt Trevor 
Published: April 2010

Measurements of the photosynthetic action and absorption spectra were made of marine Oscillatoria (Trichodesmium) from a summer surface bloom in the North Atlantic. The absorption spectrum was typical of those of other phytoplankton but with small peaks at 627 and 567 nm and a large peak at 493, consistent with the presence of phycocyanin, phycoerythrobilin, and phycourobilin respectively.The photosynthetic action spectrum was determined by measurement of the initial slope of the photosynthesis‐irradiance curve every 25 nm from 400 to 675 nm (25‐nm bandpass); it was dominated by the phycourobilin waveband. Calculations of quantum yield indicated that it was constant from 475 to 650 nm and was near maximal theoretical values. In wavebands corresponding to chlorophyll absorption (400‐450 and 675 nm), quantum yield dropped off sharply. Photosynthesis‐irradiance curves determined on both whole colonies and individual trichomes in “white” light indicated that both the initial slope and the degree of photoinhibition at high light were enhanced when the colonies were disrupted‐the former by a factor of ten, although the maximum rate of photosynthesis was unchanged. These optical and photosynthetic characteristics of marine Oscillatoria are consistent with adaptation to the high light environment where they typically bloom.
Stable carbon and nitrogen isotope biogeochemistry in the Delaware estuary
Authors: Cifuentes L. A. , Sharp J. H. , Fogel Marilyn L. 
Published: April 2010

Seasonal variability in stable carbon (δ13C) and nitrogen (δ15N) isotope ratios was observed in suspended particulate matter of the Delaware estuary. Two major pools of organic matter were found in the estuary—phytoplankton growing in situ and a mixture of planktonic and terrestrial detritus. In general, the δ13C and δ15N of suspended particulate matter reflected planktonic dominance. With the background chemical and physical information available for the estuary, it is evident that biogeochemical processes influence isotopic distributions in the estuary to a greater extent than does physical mixing. During spring, we postulate that isotopic fractionation of ammonium assimilated at concentrations >20 µM resulted in more negative δ15N values for organic matter fixed by phytoplankton. As algal growth proceeded, the δ15N of seston reached a maximum (+ 18‰) because phytoplankton were using a pool of NH4+ enriched in 15N as a result of previous fractionation during assimilation. Similarly, maximal δ13C values were related to high rates of primary productivity associated with algal growth. Decreased isotopic fractionation occurred at high rates of production, implying that diffusion of CO2 across the cell membrane became increasingly rate limiting.The δ13C values in bottom sediments were equivalent to those in suspended particulate matter, but a 2‰ difference in δ1 5N was found between suspended and bottom sediments. With nitrogen isotopic differences between water‐column seston and surficial sediments, we estimate that 15– 30% of planktonic production is deposited in the sediments during spring. If this organic matter is remineralized in late summer and fall, it could support up to 20% of primary production at that time.
Hypolimnetic metabolism in Lake Washington: Relative effects of nutrient load and food web structure on lake productivity1
Authors: Lehman John T. 
Published: April 2010

The general metabolism of carbon, oxygen, phosphate, nitrate, and silicate in the hypolimnion of Lake Washington is examined from 23 yr of record. Magnitudes of net consumptive and regenerative processes in the water column and sediments are identified and stoichiometries of regeneration in situ are calculated. Aerobic respiration appears to be almost equally divided between the water column and sediment surface. Net nitrification is more rapid in the water column, and silicate regeneration is confined to the sediment surface. Nutrients do not accumulate on average at the Redfield ratio.Rates of hypolimnetic oxygen consumption are compared to production rates inferred independently from 14C and oxygen bottle assays. A third of all gross primary production is respired in the hypolimnion of Lake Washington during spring and summer, but the proportion was significantly lower during an episode of cultural eutrophication in the 1960s. Rates of primary production and hypolimnetic processes decreased in response to changes in nutrient income when effluents from waste treatment plants were diverted from the lake. After a period of recovery from eutrophication, Lake Washington experienced a second basinwide perturbation involving alteration of the planktonic herbivore community. The change in food web structure failed to produce a response comparable to that of altered nutrient loading. Despite inferred changes in algal growth rates and in species composition, total primary productivity and rates of hypolimnetic metabolism did not change.
Imaging in Head and Neck Cancers
Authors: Patkar Deepak , Lawande Malini , Yanamandala Rama 
Published: April 2010

AbstractThis article reviews the role of imaging, imaging characteristics and significance of individual imaging modalities as well as the newer imaging modalities in the evaluation of head and neck cancer. In the pretreatment evaluation, imaging is performed primarily to determine the stage of tumor and to look for an occult primary. It helps in obtaining tissue samples to establish the diagnosis, and treatment planning if radiotherapy is considered. Postsurgery and radiotherapy changes can be differentiated from residual or recurrent pathology on imaging. Imaging also plays an important role in assessing the response to treatment.
Tracheostomy in Head and Neck Cancers
Authors: Rai Reema , Watve Parag , Hathiram Bachi T 
Published: April 2010

AbstractThe term ‘tracheostomy’ or ‘tracheotomy’ refers to the procedure whereby a communication is made between the anterior wall of the trachea and the exterior which bypasses the upper air passages. It results in the formation of a fistulous tract between the anterior aspect of the neck and the trachea allowing air to enter the lower respiratory passages without passing through the nose, pharynx and larynx.It is performed at all ages, however, there are significant differences in the procedure when performed in adults and children.‘Laryngotomy’ or ‘cricothyrotomy’ is the emergency operation where the airway is opened through the cricothyroid membrane in case of acute respiratory obstruction where there is no time for tracheostomy or inavailability of a competent surgeon to perform the tracheostomy. It is a relatively simple procedure and life-saving.
Use of Metformin in Clomiphene Citrate (CC) Resistant Polycystic Ovary Syndrome (PCOS)
Authors: Begum Mosammat Rashida , Banu Laila Arjumand , Rahman Ratu Rumana Binte , Dewan Farhana , Rouf Salma 
Published: April 2010

Abstract
Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting between 4% and 8% of reproductive aged women. Although the symptoms and signs of PCOS are very heterogeneous, the syndrome usually presents with any combination of the following, menstrual irregularities (usually oligomenorrhea or amenorrhea), signs of hyperandrogenism (hirsutism, acne, alopecia) a characteristic appearance of the ovaries on ultrasound examination and an endocrine disturbance often involving high serum concentrations of LH and androgens.
There is a well established association between PCOS, insulin resistance and hyperinsulinemia. Insulin resistance is a pivotal defect in PCOS probably counts as one of the most important advances in the battle to control the disorder. This metabolic abnormality leads to a compensatory increase in circulating insulin and this elevated insulin level directly stimulates the ovary to produce excess androgens. It also decreases hepatic sex hormone binding globulin (SHBG), so increasing biologically available free testosterone concentration in the circulation. This metabolic derangement leads to oligomenorrhea and anovulation.
Different insulin sensitizers are used to revert the hyperinsulinemic condition. Metformin is top of them, which proved to enhance ovulation in insulin resistant PCOS when used with different ovulation inducing agents. Metformin reduces insulin resistance of peripheral tissue and allows muscle and adipose cells to take in glucose at normal insulin levels. It inhibits hepatic glucose production, decreases intestinal absorption and promotes glucose uptake, utilization by peripheral tissues at the postreceptor level. In this way it reduces insulin level and subsequently androgen level. It is easily available, safe and no teratogenic or adverse fetal outcome were reported by any researcher. It can be used safely in clomiphene resistant PCOS patients.
Evaluation of Clinicosocial Factors Associated with Antepartum and Intrapartum Stillbirths at Kathmandu Medical College Teaching Hospital
Authors: Rayamajhi RT , Shreshtha N , Karki C , Padhye SM 
Published: April 2010

ABSTRACTObjectiveTo assess the prevalence and biosocial and obstetric risk factors for antepartum and intrapartum stillbirths at a tertiary hospital in Kathmandu, Nepal.Study DesignA prospective hospital based study during a one year period from 1st November 2007 to 30th October 2008.Results:18 stillbirths occurred out of the 790 deliveries that took place during the study period giving an overall stillbirth rate of 22.7 per 1000 births of which 22.2% occurred in the intrapartum period. The majority(89.9%) of patients were in the low risk age group, viz. 20-35 years. 62% were overweight, 16% obese and 22% had normal BMI. More than half (56%) were either illiterate or had only primary education and 33.3% were moderate smokers. 66.6% were nullipara and there were no grand multipara in the series. 72% had regular prenatal visits but only 33% presented with a history of loss of fetal movements. 50% delivered preterm and 22.2% were post-term while 66.6% had low birth weights. Hypertensive disorders of pregnancy and IUGR were the leading causes of stillbirths, others being prolonged PROM, cholestasis of pregnancy and congenital anomalies. 11.1% were unexplained and there was one case each of gestational diabetes, antepartum hemorrhage and vaginal breech delivery.ConclusionAvoidable intrapartum stillbirths continue to be quite high where timely and appropriate intrapartum intervention must be taken to prevent fetal loss. The identified antenatal risk factors should serve as potential targets for antenatal intervention and due importance of maternal fetal movement scoring must be stressed in the at risk patient.
Visualization of G Protein−Coupled Receptor (GPCR) Interactions in Living Cells Using Bimolecular Fluorescence Complementation (BiFC)
Authors: Vidi Pierre‐Alexandre , Przybyla Julie A. , Hu Cheng‐Deng , Watts Val J. 
Published: April 2010

AbstractMembers of the G protein−coupled receptor (GPCR) superfamily have been shown to homo‐ and hetero‐oligomerize both in vitro and in vivo. Although the functional and pharmacological significance of GPCR oligomerization is far from being completely understood, evidence suggests that, depending on the receptor, oligomerization may influence ligand binding, G protein coupling, and receptor targeting. Bimolecular fluorescence complementation (BiFC) is a technique based on the complementation of fragments from fluorescent proteins that allows the measurement and visualization of protein interactions in living cells. It can be extended to the simultaneous detection of distinct protein‐protein interactions using a multicolor setup. This unit describes the application of BiFC and multicolor BiFC to the visualization of GPCR oligomerization in a neuronal cell model. Oligomerization of GPCR fusions to BiFC tags is visualized and measured using fluorescence microscopy and fluorometry. The effect of ligands on the relative formation of distinct oligomeric species is monitored with a ratiometric multicolor BiFC approach. Curr. Protoc. Neurosci. 51:5.29.1‐5.29.15. © 2010 by John Wiley & Sons, Inc.
Endoglycosidase and Glycoamidase Release of N‐Linked Glycans
Authors: Freeze Hudson H. , Kranz Christian 
Published: April 2010

AbstractNearly all proteins entering the lumen of the endoplasmic reticulum (ER) become glycosylated en route to a cellular organelle, the plasma membrane, or the extracellular space. Many glycans can be attached to proteins, but the most common are the N‐linked glycans (oligosaccharides). These chains are added very soon after a protein enters the ER, but they undergo extensive remodeling (processing), especially in the Golgi. Processing changes the sensitivity of the N‐glycan to enzymes that cleave entire sugar chains or individual monosaccharides, which also changes the migration of the protein on SDS gels. These changes can be used to indicate when a protein has passed a particular subcellular location. This unit details some of the methods used to track a protein as it trafficks from the ER to the Golgi toward its final location. Curr. Protoc. Immunol. 89:8.15.1‐8.15.25. © 2010 by John Wiley & Sons, Inc.
Use of the Hemagglutinating Virus of Japan (HVJ) Envelope as a Versatile Delivery System for Nucleic Acids and Proteins to Leukocytes In Vitro
Authors: Kondo Yoshitaka , Miyata Keizo , Kato Fuminori 
Published: April 2010

AbstractThe hemagglutinating virus of Japan (HVJ; also called the Sendai virus) envelope has been developed as a safe and efficient non‐viral vector. Because replication and transcription of genomic RNA is inactivated by β‐propiolactone treatment or UV‐irradiation, the HVJ envelope is extremely safe. This unit describes the method of transfection of siRNA and protein with the HVJ envelope. Curr. Protoc. Immunol. 89:10.17D.1‐10.17D.9. © 2010 by John Wiley & Sons, Inc.
Amnion Epithelial Cell Isolation and Characterization for Clinical Use
Authors: Murphy Sean , Rosli Sharina , Acharya Rutu , Mathias Louisa , Lim Rebecca , Wallace Euan , Jenkin Graham 
Published: April 2010

AbstractHuman amnion epithelial cells (hAECs) are a heterologous population positive for stem cell markers; they display multilineage differentiation potential, differentiating into cells of the endoderm (liver, lung epithelium), mesoderm (bone, fat), and ectoderm (neural cells). They have a low immunogenic profile and possess potent immunosuppressive properties. Hence, hAECs may be a valuable source of cells for cell therapy. This unit describes an efficient and effective method of hAEC isolation, culture, and cryopreservation that is animal product–free and in accordance with current guidelines on preparation of cells for clinical use. Cells isolated using this method were characterized after 5 passages by analysis of karyotype, cell cycle distribution, and changes in telomere length. The differentiation potential of hAECs isolated using this animal product–free method was demonstrated by differentiation into lineages of the three primary germ layers and expression of lineage‐specific markers analyzed by PCR, immunocytochemistry, and histology. Curr. Protoc. Stem Cell Biol. 13:1E.6.1‐1E.6.25. © 2010 by John Wiley & Sons, Inc.
Monotonic and Cyclic Deformation Behaviour of the SiC Particle‐Reinforced Aluminium Matrix Composite AMC225xe
Authors: Smaga Marek , Walther Frank , Eifler Dietmar 
Published: April 2010

AbstractThe monotonic and cyclic deformation behaviour of the aluminium matrix composite AMC225xe – i.e., the aerospace grade aluminium alloy AA 2124 reinforced with 25 vol.‐% ultrafine SiC particles – is characterised in detail on the basis of mechanical stress–strain hysteresis curves as well as temperature and electrical resistance measurements. A pronounced difference in plastic strain response is observed between tension and compression under monotonic and cyclic loading. In fully reversed stress‐controlled constant amplitude tests, negative plastic mean strains developed. The cyclic deformation behaviour of AMC225xe is characterised by pronounced initial cyclic hardening. The endurance limit is reliably estimated in continuous load increase tests. In particular, electrical resistance data are used as input parameters for fatigue life calculations analogous to the Basquin equation. Microstructural details are investigated by light and scanning electron microscopy.
Al and Zn Foams Blown by an Intrinsic Gas Source
Authors: Mukherjee M. , Garcia‐Moreno F. , Jiménez C. , Banhart J. 
Published: April 2010

AbstractA method was developed to produce Al‐ and Zn‐based foams with a uniform distribution of small cells. Pre‐alloyed AlMg50 powder containing hydrogen was used as a replacement for the usual blowing agent TiH2. AlMg50 powder released gas uniformly in the entire sample, caused the nucleation of a large number of cells and led to simultaneous growth that finally resulted in a uniform cell structure. The expansion behavior of these foams was studied by means of in situ X‐ray radioscopy. The macrostructure of the solidified foams was then analyzed through optical microscopy and X‐ray tomography and proved to be very uniform. The high strength of the foams was demonstrated by uni‐axial compression tests.