bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of critical length measurements for dry snow slab weak-layer shear fracture
Authors: McClung D.M.
Published: August 2011

Snow slab avalanches primarily release by propagation of shear fractures within thin weak layers under much thicker slabs. In some cases, the weak layer is on the order of 1 mm thick and such fractures may be considered to be a mode II shear fracture at initiation. In the cases analysed in this paper, the weak layer has finite thickness, and slope-normal effects may be present. Field data from >500 snow shear fracture tests are analysed and applied to the problem of weak-layer fracture. The paper contains a detailed analysis using a simple analytical model to estimate the critical length prior to an unstable shear fracture. The model contains the assumption of a finite fracture process zone which may be a significant fraction of the slab depth,D, or the critical length,L, for weak-layer shear fracture. The field results show that theL/Dratio varies from ∼0.1 to just over 2, and the model results are close to the same range. The analysis also shows that both the field and model results forL/Dfollow a Gumbel probability density function. Since the experimental field data contain rate-dependent (viscoelastic) and slope-normal effects, it is imperative to account for these in the model and for snow slab instability evaluation when using test data. Detailed evaluations considering both these effects are given. The applicability of the test data to avalanche release is discussed.
From ice-shelf tributary to tidewater glacier: continued rapid recession, acceleration and thinning of Röhss Glacier following the 1995 collapse of the Prince Gustav Ice Shelf, Antarctic Peninsula
Authors: Glasser N.F. , Scambos T.A. , Bohlander J. , Truffer M. , Pettit E. , Davies B.J.
Published: August 2011

We use optical (ASTER and Landsat) and radar (ERS-1 and ERS-2) satellite imagery to document changes in the Prince Gustav Ice Shelf, Antarctic Peninsula, and its tributary glaciers before and after its January 1995 collapse. The satellite image record captures the transition from an ice-shelf glacier system to a tidewater glacial system and the subsequent rapid retreat and inferred ‘fatal’ negative mass balances that occur as lower glacier elevations lead to higher ablation and tidewater-style calving collapse. Pre-1995 images show that the central ice shelf was fed primarily by Sjögren Glacier flowing from the Antarctic Peninsula and by Röhss Glacier flowing from James Ross Island. Numerous structural discontinuities (rifts and crevasses) and melt ponds were present on the ice shelf before the collapse. After the ice shelf collapsed, Röhss Glacier retreated rapidly, becoming a tidewater glacier in 2002 and receding a total of ∼15 km between January 2001 and March 2009, losing >70% of its area. Topographic profiles of Röhss Glacier from ASTER-derived digital elevation models show a thinning of up to ∼150 m, and surface speeds increased up to ninefold (0.1–0.9 m d−1) over the same period. The rates of speed increase and elevation loss, however, are not monotonic; both rates slowed between late 2002 and 2005, accelerated in 2006 and slowed again in 2008–09. We conclude that tributary glaciers react to ice-shelf removal by rapid (if discontinuous) recession, and that the response of tidewater glaciers on the Antarctic Peninsula to ice-shelf removal occurs over timescales ranging from sub-annual to decadal.
Waterfall ice: mechanical stability of vertical structures
Authors: Weiss J. , Montagnat M. , Cinquin-Lapierre B. , Labory P.A. , Moreau L. , Damilano F. , Lavigne D.
Published: August 2011

We present a study of the mechanical (in)stability of the ephemeral waterfall ice structures that form from the freezing of liquid water seeping on steep rock. Three vertical structures were studied, two near Glacier d’Argentière, France, and one in the Valsavarenche valley, northern Italy. The generation of internal stresses in the ice structure in relation to air- and ice-temperature conditions is analyzed from pressure sensor records. Their role in the mechanical instability of the structures is discussed from a photographic survey of these structures. The main result is that dramatic air cooling (several °Ch−1 over several hours) and low temperatures (<−10°C), generating tensile stresses and brittleness, can trigger a spontaneous or climber-induced mechanical collapse, leading to unfavorable climbing conditions. Ice internal pressure fluctuations are also associated with episodes of marked diurnal air-temperature cycle, with mild days (few above 0) and cool nights (few below 0), through the occurrence of water ↔ ice phase transitions within the structure. These ice internal stress fluctuations seem, however, to have a local influence, are associated with warm (near 0), wet and therefore particularly soft ice and do not trigger a collapse of the structure.
Glacier changes in the Garhwal Himalaya, India, from 1968 to 2006 based on remote sensing
Authors: Bhambri Rakesh , Bolch Tobias , Chaujar Ravinder Kumar , Kulshreshtha Subhash Chandra
Published: August 2011

Glacier outlines are mapped for the upper Bhagirathi and Saraswati/Alaknanda basins of the Garhwal Himalaya using Corona and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite images acquired in 1968 and 2006, respectively. A subset of glaciers was also mapped using Landsat TM images acquired in 1990. Glacier area decreased from 599.9 ± 15.6 km2(1968) to 572.5 ± 18.0 km2(2006), a loss of 4.6 ± 2.8%. Glaciers in the Saraswati/Alaknanda basin and upper Bhagirathi basin lost 18.4 ± 9.0 km2(5.7 ± 2.7%) and 9.0 ± 7.7 km2(3.3 ± 2.8%), respectively, from 1968 to 2006. Garhwal Himalayan glacier retreat rates are lower than previously reported. More recently (1990–2006), recession rates have increased. The number of glaciers in the study region increased from 82 in 1968 to 88 in 2006 due to fragmentation of glaciers. Smaller glaciers (<1 km2) lost 19.4 ± 2.5% (0.51 ± 0.07% a−1) of their ice, significantly more than for larger glaciers (>50 km2) which lost 2.8 ± 2.7% (0.074 ± 0.071 % a−1). From 1968 to 2006, the debris-covered glacier area increased by 17.8 ± 3.1% (0.46 ± 0.08% a−1) in the Saraswati/Alaknanda basin and 11.8 ± 3.0% (0.31 ± 0.08% a−1) in the upper Bhagirathi basin. Climate records from Mukhim (∼1900 m a.s.l.) and Bhojbasa (∼3780 m a.s.l.) meteorological stations were used to analyze climate conditions and trends, but the data are too limited to make firm conclusions regarding glacier–climate interactions.
The effect of fluctuations in surface density, accumulation and compaction on elevation change rates along the EGIG line, central Greenland
Authors: Morris Elizabeth M. , Wingham Duncan J.
Published: August 2011

Repeated measurements of density profiles and surface elevation along a 515 km section of the Greenland ice sheet have been used to determine elevation change rates and the error in determining mass balance from these rates which arises from short-term fluctuations in mass input, compaction and surface density. Over the 28 months from spring 2004 to summer 2006 the average error over 100 km sections of the traverse ranged from −0.006 to 0.100 ma−1. The lowest values, comparable with the system accuracy of the CryoSat radar altimeter (0.033 m a−1), were found below 3000 m. The surface density required to translate the elevation change into mass change decreased from 0.40 g cm−3 at an elevation of 2348 m to 0.33 g cm−3 at an elevation of 3264 m. From the density profiles the equivalent values for a time period of 10 years were found to be 0.48 and 0.38 g cm−3, respectively.
A scanning electron microscope technique for identifying the mineralogy of dust in ice cores
Authors: Obbard Rachel W. , Baker Ian , Prior David J.
Published: August 2011

Dust particles in an ice core from East Rongbuk Glacier on the northern slope of Qomolangma (Mount Everest; 28°01′ N, 86°58′ E; 6518 m a.s.l.), central Himalaya, have been identified as mica using a combination of scanning electron microscope-based techniques and energy-dispersive X-ray spectroscopy to identify the elements present, and electron backscatter diffraction to identify the crystal type. This technique for identifying individual crystalline dust particles in samples of glacial ice could be especially useful in the future for identifying water-soluble crystals in ice, for studying the strain history (glaciotectonics) of basal ice or in studies of ice–mica composites used as analogs of quartz-mica rocks.
Multi-decadal retreat of Greenland’s marine-terminating glaciers
Authors: Howat Ian M. , Eddy Alex
Published: August 2011

Many marine-terminating glaciers draining the Greenland ice sheet have retreated over the past decade, yet the extent and magnitude of retreat relative to past variability is unknown. We measure changes in front positions of 210 marine-terminating glaciers using Landsat imagery spanning nearly four decades and compare decadal-scale rates of change with earlier observations. We find that 90% of the observed glaciers retreated between 2000 and 2010, approaching 100% in the northwest, with rapid retreat observed in all sectors of the ice sheet. The current retreat is accelerating and likely began between 1992 and 2000, coincident with the onset of warming, following glacier stability and minor advance during a mid-century cooling period. While it is clear an extensive retreat occurred in the early 20th century, a period of increasing air temperatures, a comparison of our results with historical observations provides evidence that the current retreat is more widespread. The onset of rapid retreat with warming relative to the slow and lagged advance with cooling suggests an asymmetry in the response of marine fronts to external forcing.
What do glaciers tell us about climate variability and climate change?
Authors: Roe Gerard H.
Published: August 2011

Glaciers respond to long-term climate changes and also to the year-to-year fluctuations inherent in a constant climate. Differentiating between these factors is critical for the correct interpretation of past glacier fluctuations and for the correct attribution of current changes. Previous work has established that century-scale, kilometre-scale fluctuations can occur in a constant climate. This study asks two further questions of practical significance: how likely is an excursion of a given magnitude in a given amount of time, and how large a trend in length is statistically significant? A linear model permits analytical answers wherein the dependencies on glacier geometry and climate setting can be clearly understood. The expressions are validated with a flowline glacier model. The likelihood of glacier excursions is well characterized by extreme-value statistics, although probabilities are acutely sensitive to some poorly known glacier properties. Conventional statistical tests can be used for establishing the significance of an observed glacier trend. However, it is important to determine the independent information in the observations which can be effectively estimated from the glacier geometry. Finally, the retreat of glaciers around Mount Baker, Washington State, USA, is consistent with, but not independent proof of, the regional climate warming that is established from the instrumental record.
Icequakes coupled with surface displacements for predicting glacier break-off
Authors: Faillettaz Jérome , Funk Martin , Sornette Didier
Published: August 2011

A hanging glacier at the east face of Weisshorn, Switzerland, broke off in 2005. We were able to monitor and measure surface motion and icequake activity for 25 days up to 3 days prior to the break-off. The analysis of seismic waves generated by the glacier during the rupture maturation process revealed four types of precursory signals of the imminent catastrophic rupture: (1) an increase in seismic activity within the glacier; (2) a change in the size–frequency distribution of icequake energy; (3) a modification in the structure of the waiting-time distributions between two successive icequakes; and (4) a correlation between the seismic activity and the log-periodic oscillations of the surface velocities superimposed on the global acceleration of the glacier during the rupture maturation. Analysis of the seismic activity led us to identify two regimes: a stable phase with diffuse damage and an unstable and dangerous phase characterized by a hierarchical cascade of rupture instabilities where large icequakes are triggered.
The atmospheric snow-transport model: SnowDrift3D
Authors: Schneiderbauer Simon , Prokop Alexander
Published: August 2011

SnowDrift3D, a high-resolution, atmospheric snow-transport model, is presented for the first time. In contrast to most state-of-the-art snowdrift models, atmospheric particle transport, i.e. saltation and suspension, is accounted for by one passive transport equation. The model uses unsteady wind fields (spatial resolution of up to 2 m) computed with an atmospheric computational fluid dynamics model that is directly connected to the numerical weather prediction model ALADIN. Sensitivity runs show that (1) the saltation mass flux is a function of cubic shear velocity, , (2) the model is marginally sensitive to the grid spacing at high resolutions (up to 2 m), (3) the model computes the redistribution of snow at high resolution in real time on dual core personal computers and (4) the changing topography of the snow cover should be included in cases of local erosion or deposition of a large amount of snow. Finally, we present a comparison of modeled and measured snow distributions obtained by terrestrial laser scanning showing area-wide linear correlation up to R = 0.33.
Glide avalanche response to an extreme rain-on-snow event, Snoqualmie Pass, Washington, USA
Authors: Stimberis John , Rubin Charles M.
Published: August 2011

Rain-on-snow events trigger immediate and delayed avalanches as liquid water penetrates the snowpack. We present results from an extreme rain-on-snow event that triggered a glide avalanche near Snoqualmie Pass, Washington, USA. Snoqualmie Pass recorded 463 cm of snowfall from 13 December 2008 to 6 January 2009. This period of snowfall was followed by a strong southwesterly tropical flow that resulted in an extreme rain-on-snow event. Sensors at Snoqualmie Pass recorded 285 mm of precipitation over a 52 hour period. Flooding, slush flows, landslides and avalanches resulted from the influx of precipitation. Snow heights decreased rapidly over the period, with settlement rates approaching 80 mm h−1. Liquid water infiltrated and flowed through the snowpack within a few hours of the arrival of rain, yet many of the major avalanches occurred 12–30 or more hours after the onset of rain and water outflow. A glide avalanche occurred ∼30 hours after the onset of rain and the establishment of drainage through the snowpack. Increasing glide rates correlate with periods of rapid snow settlement. Here glide rates approached 670 mm h−1. Although glide and settlement rates increased during periods of intense precipitation, glide failure occurred 8 hours after peak precipitation and outflow.
Molecular methods in medical microbiology: Current and future trends
Authors: Rahman MM
Published: August 2011

DOI: http://dx.doi.org/ 10.3329/bjms.v10i3.8355BJMS 2011; 10(3): 141-147
Anemia in Sudanese patients with chronic renal failure (CRF) and in patients undergoing chronic hemodialysis
Authors: Fathelrahman MH
Published: August 2011

Background: The term of anemia of chronic renal failure (CRF) in sufficiency refers to that anemia resulting directly from failure of the endocrine and excretory functions of the kidney and decreased production of erythropoietin by damaged kidneys. The serum erythropoietin level in patients with renal failure does not increase in response to the developing anemia, which is the primary cause of inadequate erythropoiesis. Aim: The purpose of our study was to examine, among patients with CRF, the combined association of CRF and anemia on adverse outcomes. Settings and Design: A hospitalized study using administrative data, we identified all patients hospitalized with CRF in IBN-Sena hospital and Khartoum teaching hospitals, Khartoum, Sudan. Materials and Methods: This was a retrospective cohort study of 500 patients having a diagnosis of chronic renal failure hospitalized and discharged between October 2007 to February 2010 from two Sudanese Teaching hospitals (Khartoum and IBN-Sena). All adult patients with chronic renal failure hospitalized for hemodialysis. Results: Hemoglobin level was recorded for 500 members (100%) of the cohort. The mean (SD) hemoglobin was 13.0 g/dL (2.2) range from 11.8 g/dL to 14.6 g/dL. On admission, an hemoglobin of ≥ 14 g/dL was found in 36.2% of the patients, 36.2% had an hemoglobin between 12 g/dL and 14 g/dL, 19.6% between 10 g/dL and 12 g/dL, and 8% ≤ 10 g/dL. The proportion of patients with CRF was associated with increasing anemia. Conclusion: The results obtained indicated the further evidence that the concomitant presence of either CRF or anemia increased the risk of dying in the hospital or of being readmitted within 30 days among patients hospitalized. The association persisted after controlling for other factors associated with adverse outcomes in these patients. Key words: Anemia, chronic renal failure. DOI: http://dx.doi.org/ 10.3329/bjms.v10i3.8357 BJMS 2011; 10(3): 152-158
Risk factors for hepatitis C disease in Tando Allahyar, Pakistan: a case-control study
Authors: Channa NA , Khan H
Published: August 2011

Objective: Present study was undertaken to explore the epidemiological and dietary risk factors for hepatitis C disease in Tando Allahyar during June to December 2007. Materials and methods: 140 Hepatitis C patients and 149 controls (age, sex and locality matched with no personal or family history of hepatitis C) were randomly selected from the Tando Allahyar population during June 2007 to December 2007. A standard questionnaire specially developed for that purpose, was distributed among patients and controls. Accurate rapid card test was performed to confirm Hepatitis C virus (HCV) positive or negative patients and controls. O.R with 95% confidence interval was computed and p values were calculated by chi square test. Results: Over all findings showed that among 140 HCV patients 64% were females and 36% males (mean age range was 20-48 years). Our results showed strong positive association of sedentary life style (OR=4, 95% CI, 1.48-10.6, p=0.005), marital status, +ve family history, B+ve blood group, piercing, syringe use (70%), multiple pregnancies (OR=4.72, 95% CI, 1.47-15.15, p=0.008), blood transfusion (OR=4.4, 95% CI, 1.2-14.95, p=0.017), take out food debris by office pins (NS), shave at barber’s shop (NS), dental procedures (NS), medicines used in past (OR=3.08, 95% CI, 1.2-7.71, P=0.016), G.I.T diseases (OR =8.66, 95% CI, 1.28-55.58, p=0.023), stones of kidney or gallbladder, jaundice, Tuberculosis and psychological problems (OR =2.5, 95% CI, 1.04-6.13, P=0.04) with hepatitis C disease. We did not find any association of surgery, BMI, ENT, diseases, meat consumption and smoking with the disease. Vegetables OR =0.842, 95% CI, 0.361-1.964, P=0.694), pulses, tomatoes (OR =0.31, 95% CI, 0.041-2.53, P=0.31), and tea (OR =0.598, 95% CI, 0.251-1.431, P=0.25) were found to be the protective factors for Hepatitis C disease. Conclusion: Sedentary life style, multiple pregnancies, blood transfusion, medicines used in past, G.I.T diseases, and psychological problems are significantly positively associated with Hepatitis C disease. Key words: Hepatitis C disease, HCV infection, epidemiological risk factors, Diet, blood transfusion, G.I.T diseases, and psychological problems. DOI: http://dx.doi.org/ 10.3329/bjms.v10i3.8359 BJMS 2011; 10(3): 163-169
Effects of maternal anaemia on neonatal outcome  a study done in the specialized urban hospital set up in Bangladesh
Authors: Mahamuda B , Tanira S , Feroza W , Perven HA , Shamim A
Published: August 2011

Context: Anaemia is a common pregnancy related disorder in Bangladesh that causes various maternal and fetal problems. A prospective study was designed to see the associated maternal factors and fetal outcome in different categories of anaemia and to compare with that of normal pregnancy. Methods: The study was carried out on 60 Bangladeshi women within 35-40 weeks of gestation. Among them, 20 with normal uncomplicated pregnancies were considered as control group or group A, another 27 having pregnancies with mild anaemia were considered as group B, and 13 having pregnancies with moderate anaemia were considered as group C. Severe anaemic mothers were considered as group D, but not found during the period of collection of data for this study. The mothers were selected as who were suffering from antenatal anaemia i.e. having heamoglobin level <10 gm/dl (mild, if <10 gm/dl; moderate, if <8 gm/dl; and severe, if <6 gm/dl) and control i.e. having heamoglobin level ≥10 gm/dl. The foetal outcome was observed and recorded after delivery. Results: The mean age of the mother was 23.65±3.83 years, 27.26±4.93 years and 25.85±4.62 years and the mean number of gravidity was 1.65±0.67, 2.15±0.72 and 2.69±1.03 in group A, group B and group C respectively. The difference was statistically highly significant in between A and C (p<0.001) and also significant in between A & B and B & C (p<0.05). The mean gestational age of the mother was 38.65±0.88 weeks, 37.37±1.01 weeks and 37.15±1.28 weeks in group A, group B and group C respectively and the difference was statistically significant between A & B and A & C (p<0.001). The mean birth weight of the neonate was 3.09±0.30 Kg., 2.99±0.16 Kg. and 2.95±0.21 Kg., while the mean APGAR score of the neonate at first minute of birth was 8.90±1.07, 8.11±0.89 and 7.69±0.48 in group A, group B and group C respectively. No significant difference was found in birth weight of the newborn babies in between the groups of the mothers. However, the difference was found significant in between A & B (p<0.01) and A & C (p<0.001), in case of APGAR score. Key words: Maternal anaemia, gestational age, neonatal outcome, birth weight, APGAR score. DOI: http://dx.doi.org/10.3329/bjms.v10i3.8361 BJMS 2011; 10(3): 177-180
Neonatal bacteremia in a neonatal intensive care unit: analysis of causative organisms and antimicrobial susceptibility
Authors: Hafsa A , Fakruddin M , Hakim MA , Sharma JD
Published: August 2011

Background: Bangladesh has a neonatal death rate that is substantially high and demands urgent attention. Objective: This retrospective study was performed to determine the incidence of bacterial neonatal sepsis condition in the Chittagong area of Bangladesh with focus on various demographic characteristics of neonates, causative organisms and their antibiotic susceptibility. Methodology: Blood culture was performed on all neonates with risk factors or signs of suggestive sepsis. Blood samples were cultured using tryptone soya broth (TSB- blood broth) according to standard method. Results: From the 1400 neonates 104 had positive blood culture for neonatal sepsis infection. Among the infected children 40 (38.46%) were born in the hospital and 64 (61.54%) were born at home. The EONS (Early Onset Neonatal Sepsis) accounted for 68 (65.38%) and LONS (Late Onset Neonatal Sepsis) accounted for 36 (34.62%). Among the isolated organism Klebsiella pneumoniae accounted for 79 (75.96%), Serratia marcescens 19 (18.27%), Pseudomonas aeruginosa 04 (3.85%) and Staphylococcus aureus accounted for 02 (1.92%). Among the isolated species 102 were attributed to G (-ve) bacteria and 02 were attributed to G (+ve) bacteria. Most of the G (-ve) bacteria showed resistance to commonly used antibiotics such as ampicillin, ceftriaxon and gentamicin. In this study all isolates showed sensitivity to the imipenem. Conclusion: Collection of up-to-date data is mandatory for appropriate use of antibiotics. Key words: Neonatal sepsis, Interleukin-6, antibiotics, susceptibility. DOI: http://dx.doi.org/10.3329/bjms.v10i3.8363 BJMS 2011; 10(3): 187-194
Non-syndromic oligodontia  Report of a clinical case with 14 missing teeth
Authors: Nagaveni NB , Umashankara KV , Radhika NB , Satisha TS
Published: August 2011

Oligodontia (severe partial anodontia) is a rare developmental dental anomaly refers to congenital lack of more than six teeth. Most often oligodontia appears as part of some congenital syndromes that affects several organ systems. The exact etiology for oligodontia is unknown. Management includes various restorative and orthodontic procedures to improve the esthetics and function. The present article reports a case of oligodontia of 14 number of permanent teeth excluding third molars in a non-syndromic female patient. Key words: oligodontia; hypodontia, partial anodontia, tooth agenesis. DOI: http://dx.doi.org/10.3329/bjms.v10i3.8365 BJMS 2011; 10(3): 200-202
Oral myiasis: a case report
Authors: Sikder MS , Pradhan L , Ferdousi F , Parvin MK
Published: August 2011

Oral Myiasis is a condition in which the soft tissues of different parts of oral cavity are invaded by the parasitic larvae of flies known as Maggots. This study presents a case of oral myiasis in 12 years old mentally retarded girl. Clinically, the patient had multiple perforations of the palatal mucosa at mid-hard palate and tunneling of the palatal gingivae from lateral incisor to the first molar on either side communicated to the palatal perforations. The patient was treated by mechanical removal of the maggots with simple curettage and irrigation with paraffin, povidone iodine and normal saline. After complete larvae removal, the wounds healed normally. Key words: Oral myiases, mentally retarded, fly larvae. DOI: http://dx.doi.org/10.3329/bjms.v10i3.8367 BJMS 2011; 10(3): 206-208
Edwards syndrome with a novel karyotype
Authors: Patra S , Garg A , Krishnamurthy S , Aneja S
Published: August 2011

Edward’s syndrome was first described as a clinical entity in 1960 as a disorder of trisomy 18 (47 XX/XY; + 18) in babies with particular pattern of malformations. The Karyotype found in our case was (47 XX + 18 add (22) (p13) which has not been published so far in the literature. The less common findings noted in the baby were rocker bottom feet, syndactyly of 2nd and 3rd toes, microcephaly and corneal opacities. Though we didn’t find any significant association between phenotypic ranges with genotypic variation in literature, but further research is needed for it. We are reporting this case as the genotype is found to be novel. Keywords: Edward’s syndrome, karyotype, neonate. DOI: http://dx.doi.org/10.3329/bjms.v10i3.8368 BJMS 2011; 10(3): 211-212
Therapeutic Approaches to Target Cancer Stem Cells
Authors: Diaz Arlhee , Leon Kalet
Published: August 2011

The clinical relevance of cancer stem cells (CSC) remains a major challenge for current cancer therapies, but preliminary findings indicate that specific targeting may be possible. Recent studies have shown that these tumor subpopulations promote tumor angiogenesis through the increased production of VEGF, whereas the VEGF neutralizing antibody bevacizumab specifically inhibits CSC growth. Moreover, nimotuzumab, a monoclonal antibody against the epidermal growth factor receptor (EGFR) with a potent antiangiogenic activity, has been shown by our group to reduce the frequency of CSC-like subpopulations in mouse models of brain tumors when combined with ionizing radiation. These studies and subsequent reports from other groups support the relevance of approaches based on molecular-targeted therapies to selectively attack CSC. This review discusses the relevance of targeting both the EGFR and angiogenic pathways as valid approaches to this aim. We discuss the relevance of identifying better molecular markers to develop drug screening strategies that selectively target CSC.
Thermodynamics of Thermoelectric Phenomena and Applications
Authors: Goupil Christophe , Seifert Wolfgang , Zabrocki Knud , Müller Eckhart , Snyder G. Jeffrey
Published: August 2011

Fifty years ago, the optimization of thermoelectric devices was analyzed by considering the relation between optimal performances and local entropy production. Entropy is produced by the irreversible processes in thermoelectric devices. If these processes could be eliminated, entropy production would be reduced to zero, and the limiting Carnot efficiency or coefficient of performance would be obtained. In the present review, we start with some fundamental thermodynamic considerations relevant for thermoelectrics. Based on a historical overview, we reconsider the interrelation between optimal performances and local entropy production by using the compatibility approach together with the thermodynamic arguments. Using the relative current density and the thermoelectric potential, we show that minimum entropy production can be obtained when the thermoelectric potential is a specific, optimal value.
Spatial Variation of Surface Soil Available Phosphorous and Its Relation with Environmental Factors in the Chaohu Lake Watershed
Authors: Gao Yongnian , Gao Junfeng , Chen Jiongfeng
Published: August 2011

The study presented in this paper attempts to evaluate the spatial pattern of soil available phosphorus, as well as the relation between soil available phosphorus and environment factors including elevation, slope, precipitation, percentage of cultivated land, percentage of forest land, percentage of construction land and NDVI using statistical methods and GIS spatial analysis techniques. The results showed that the Spline Tension method performed the best in the prediction of soil available phosphorus in the Chaohu Lake watershed. The spatial variation of surface soil available phosphorus was high in Chaohu Lake watershed and the upstream regions around Chaohu Lake, including the west of Chaohu lake (e.g., southwest of Feixi county, east of Shucheng county and north of Lujiang county) and to the north of Chaohu Lake (e.g., south of Hefei city, south of Feidong county, southwest of Juchao district), had the highest soil available phosphorus content. The mean and standard deviation of soil available phosphorus content gradually decreased as the elevation or slope increased. The cultivated land comprised 60.11% of the watershed and of that land 65.63% belonged to the medium to very high SAP level classes, and it played a major role in SAP availability within the watershed and a potential source of phosphorus to Chaohu Lake resulting in eutrophication. Among the land use types, paddy fields have some of the highest maximum values and variation of coefficients. Subwatershed scale soil available phosphorus was significantly affected by elevation, slope, precipitation, percentage of cultivated land and percentage of forest land and was decided by not only these environmental factors but also some other factors such as artificial phosphorus fertilizer application.
Design and Calibration of an Organic Diffusive Probe to Extend the Diffusion Gradient Technique to Organic Pollutants
Authors: Bondarenko Antonina , Sani Daniela , Ruello Maria Letizia
Published: August 2011

The objective of this study was to develop a method for measuring the mobility of persistent organic pollutants in the solid phase of soils within the context of environmental pollution risk assessment. A new diffusive probe, purposely designed by adapting the diffusive gradient technique method, measures labile organic species by immobilizing them after diffusion through a thin deionized water layer. The measure of the mass accumulated is used to calculate the flow of pollutant from solid phase to pore water. Naphthalene was chosen as a model persistent organic pollutant. The probe was calibrated at different temperatures and was then tested in several microcosms at different porosity and reactivities with naphthalene (one clay soil, two sandy soils and one natural soil). The probe response showed good agreement with the expected different abilities of the solid phases in restoring the solution phase. The concentration of naphthalene in the pore water was well buffered by rapid equilibria with the solid phase in the investigated natural soil. In contrast, pore water concentration in the sandy soils decreased rapidly and the flow was slackened, especially for the sandy soil with finer particles. In clay, only a fraction of the total naphthalene content was present in the labile fraction, while the remaining was tightly bound and was not released to the pore water. Therefore, this first stage of testing points out that the diffusive gradient technique, if optimized, can properly quantify the mobility of organic pollutants in soil.
Self-Assembly of Protein Monolayers Engineered for Improved Monoclonal Immunoglobulin G Binding
Authors: Le Brun Anton P. , Shah Deepan S. H. , Athey Dale , Holt Stephen A. , Lakey Jeremy H.
Published: August 2011

Bacterial outer membrane proteins, along with a filling lipid molecule can be modified to form stable self-assembled monolayers on gold. The transmembrane domain of Escherichia coli outer membrane protein A has been engineered to create a scaffold protein to which functional motifs can be fused. In earlier work we described the assembly and structure of an antibody-binding array where the Z domain of Staphylococcus aureus protein A was fused to the scaffold protein. Whilst the binding of rabbit polyclonal immunoglobulin G (IgG) to the array is very strong, mouse monoclonal IgG dissociates from the array easily. This is a problem since many immunodiagnostic tests rely upon the use of mouse monoclonal antibodies. Here we describe a strategy to develop an antibody-binding array that will bind mouse monoclonal IgG with lowered dissociation from the array. A novel protein consisting of the scaffold protein fused to two pairs of Z domains separated by a long flexible linker was manufactured. Using surface plasmon resonance the self-assembly of the new protein on gold and the improved binding of mouse monoclonal IgG were demonstrated.
Major Histocompatibility Complex (MHC) Markers in Conservation Biology
Authors: Ujvari Beata , Belov Katherine
Published: August 2011

Human impacts through habitat destruction, introduction of invasive species and climate change are increasing the number of species threatened with extinction. Decreases in population size simultaneously lead to reductions in genetic diversity, ultimately reducing the ability of populations to adapt to a changing environment. In this way, loss of genetic polymorphism is linked with extinction risk. Recent advances in sequencing technologies mean that obtaining measures of genetic diversity at functionally important genes is within reach for conservation programs. A key region of the genome that should be targeted for population genetic studies is the Major Histocompatibility Complex (MHC). MHC genes, found in all jawed vertebrates, are the most polymorphic genes in vertebrate genomes. They play key roles in immune function via immune-recognition and -surveillance and host-parasite interaction. Therefore, measuring levels of polymorphism at these genes can provide indirect measures of the immunological fitness of populations. The MHC has also been linked with mate-choice and pregnancy outcomes and has application for improving mating success in captive breeding programs. The recent discovery that genetic diversity at MHC genes may protect against the spread of contagious cancers provides an added impetus for managing and protecting MHC diversity in wild populations. Here we review the field and focus on the successful applications of MHC-typing for conservation management. We emphasize the importance of using MHC markers when planning and executing wildlife rescue and conservation programs but stress that this should not be done to the detriment of genome-wide diversity.
A Comparative Reverse Docking Strategy to Identify Potential Antineoplastic Targets of Tea Functional Components and Binding Mode
Authors: Zheng Rong , Chen Tuan-sheng , Lu Tun
Published: August 2011

The main functional components of green tea, such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC), are found to have a broad antineoplastic activity. The discovery of their targets plays an important role in revealing the antineoplastic mechanism. Therefore, to identify potential target proteins for tea polyphenols, we have taken a comparative virtual screening approach using two reverse docking systems, one based on Autodock software and the other on Tarfisdock. Two separate in silico workflows were implemented to derive a set of target proteins related to human diseases and ranked by the binding energy score. Several conventional clinically important proteins with anti-tumor effects are screened out from the PDTD protein database as the potential receptors by both procedures. To further analyze the validity of docking results, we study the binding mode of EGCG and the potential target protein Leukotriene A4 hydrolase in detail. We indicate that interactions mediated by electrostatic and hydrogen bond play a key role in ligand binding. EGCG binds to the enzyme with certain orientation and conformation that is suitable for nucleophilic attacks by several electrical residues inside the enzyme’s activity cavity. This study provides useful information for studying the antitumor mechanism of tea’s functional components. The comparative reverse docking strategy presented generates a tractable set of antineoplastic proteins for future experimental validation as drug targets against tumors.
Mechanisms of Mycotoxin-Induced Neurotoxicity through Oxidative Stress-Associated Pathways
Authors: Doi Kunio , Uetsuka Koji
Published: August 2011

Among many mycotoxins, T-2 toxin, macrocyclic trichothecenes, fumonisin B1 (FB1) and ochratochin A (OTA) are known to have the potential to induce neurotoxicity in rodent models. T-2 toxin induces neuronal cell apoptosis in the fetal and adult brain. Macrocyclic trichothecenes bring about neuronal cell apoptosis and inflammation in the olfactory epithelium and olfactory bulb. FB1 induces neuronal degeneration in the cerebral cortex, concurrent with disruption of de novo ceramide synthesis. OTA causes acute depletion of striatal dopamine and its metabolites, accompanying evidence of neuronal cell apoptosis in the substantia nigra, striatum and hippocampus. This paper reviews the mechanisms of neurotoxicity induced by these mycotoxins especially from the viewpoint of oxidative stress-associated pathways.
Analgesic and Anti-Inflammatory Activities of Salicylaldehyde 2-Chlorobenzoyl Hydrazone (H2LASSBio-466), Salicylaldehyde 4-Chlorobenzoyl Hydrazone (H2LASSBio-1064) and Their Zinc(II) Complexes
Authors: Júnior Walfrido Bispo , Alexandre-Moreira Magna S. , Alves Marina A. , Perez-Rebolledo Anayive , Parrilha Gabrieli L. , Castellano Eduardo E. , Piro Oscar E. , Barreiro Eliezer J. , Lima Lídia Moreira , Beraldo Heloisa
Published: August 2011

Salicylaldehyde 2-chlorobenzoyl hydrazone (H2LASSBio-466), salicylaldehyde 4-chlorobenzoyl hydrazone (H2LASSBio-1064) and their complexes [Zn(LASSBio-466)H2O]2 (1) and [Zn(HLASSBio-1064)Cl]2 (2) were evaluated in animal models of peripheral and central nociception, and acute inflammation. All studied compounds significantly inhibited acetic acid-induced writhing response. Upon coordination the anti-nociceptive activity was favored in the complex 1. H2LASSBio-466 inhibited only the first phase of the formalin test, while 1 was active in the second phase, like indomethacin, indicating its ability to inhibit nociception associated with the inflammatory response. Hence coordination to zinc(II) altered the pharmacological profile of H2LASSBio-466. H2LASSBio-1064 inhibited both phases but this effect was not improved by coordination. The studied compounds did not increase the latency of response in the hot plate model, indicating their lack of central anti-nociceptive activity. All compounds showed levels of inhibition of zymosan-induced peritonitis comparable or superior to indomethacin, indicating an expressive anti-inflammatory profile.
Selective Covalent Conjugation of Phosphorothioate DNA Oligonucleotides with Streptavidin
Authors: Rabe Kersten S. , Niemeyer Christof M.
Published: August 2011

Protein-DNA conjugates have found numerous applications in the field of diagnostics and nanobiotechnology, however, their intrinsic susceptibility to DNA degradation by nucleases represents a major obstacle for many applications. We here report the selective covalent conjugation of the protein streptavidin (STV) with phosphorothioate oligonucleotides (psDNA) containing a terminal alkylthiolgroup as the chemically addressable linking unit, using a heterobifunctional NHS-/maleimide crosslinker. The psDNA-STV conjugates were synthesized in about 10% isolated yields. We demonstrate that the terminal alkylthiol group selectively reacts with the maleimide while the backbone sulfur atoms are not engaged in chemical conjugation. The novel psDNA-STV conjugates retain their binding capabilities for both biotinylated macromolecules and the complementary nucleic acid. Moreover, the psDNA-STV conjugate retained its binding capacity for complementary oligomers even after a nuclease digestion step, which effectively degrades deoxyribonucleotide oligomers and thus the binding capability of regular DNA-STV conjugates. The psDNA-STV therefore hold particular promise for applications e.g. in proteome research and novel biosensing devices, where interfering endogenous nucleic acids need to be removed from analytes by nuclease digestion.
Synthesis of Porphyrin-Dendrimers with a Pyrene in the Periphery and Their Cubic Nonlinear Optical Properties
Authors: Morales-Espinoza Eric G. , Lijanova Irina V. , Morales-Saavedra Omar G. , Torres-Zuñiga Vícente , Hernandez-Ortega Simon , Martínez-García Marcos
Published: August 2011

Dendrons of pyrene derivatives were attached to a porphyrin core. A marked effect in solution for the dendrimers was observed in the absorption spectra. All the compounds obtained were characterized by 1H-, 13C-NMR, FTIR, UV-vis, MALDI-TOF or FAB+ mass spectrometry and elemental analysis. The cubic nonlinear optical behavior of some the synthesized compounds was tested via Z-Scan measurements in spin-coated film samples.
Timing Constraints on Remote Sensing of Wildland Fire Burned Area in the Southeastern US
Authors: Picotte Joshua J. , Robertson Kevin
Published: August 2011

Remote sensing using Landsat Thematic Mapper (TM) satellite imagery is increasingly used for mapping wildland fire burned area and burn severity, owing to its frequency of collection, relatively high resolution, and availability free of charge. However, rapid response of vegetation following fire and frequent cloud cover pose challenges to this approach in the southeastern US. We assessed these timing constraints by using a series of Landsat TM images to determine how rapidly the remotely sensed burn scar signature fades following prescribed burns in wet flatwoods and depression swamp community types in the Apalachicola National Forest, Florida, USA during 2006. We used both the Normalized Burn Ratio (NBR) of reflectance bands sensitive to vegetation and exposed soil cover, as well as the change in NBR from before to after fire (dNBR), to estimate burned area. We also determined the average and maximum amount of time following fire required to obtain a cloud-free image for burns in each month of the year, as well as the predicted effect of this time lag on percent accuracy of burn scar estimates. Using both NBR and dNBR, the detectable area decreased linearly 9% per month on average over the first four months following fire. Our findings suggest that the NBR and dNBR methods for monitoring burned area in common southeastern US vegetation community types are limited to an average of 78–90% accuracy among months of the year, with individual burns having values as low as 38%, if restricted to use of Landsat 5 TM imagery. However, the majority of burns can still be mapped at accuracies similar to those in other regions of the US, and access to additional sources of satellite imagery would improve overall accuracy.
Field Programmable Gate Array Based Parallel Strapdown Algorithm Design for Strapdown Inertial Navigation Systems
Authors: Li Zong-Tao , Wu Tie-Jun , Lin Can-Long , Ma Long-Hua
Published: August 2011

A new generalized optimum strapdown algorithm with coning and sculling compensation is presented, in which the position, velocity and attitude updating operations are carried out based on the single-speed structure in which all computations are executed at a single updating rate that is sufficiently high to accurately account for high frequency angular rate and acceleration rectification effects. Different from existing algorithms, the updating rates of the coning and sculling compensations are unrelated with the number of the gyro incremental angle samples and the number of the accelerometer incremental velocity samples. When the output sampling rate of inertial sensors remains constant, this algorithm allows increasing the updating rate of the coning and sculling compensation, yet with more numbers of gyro incremental angle and accelerometer incremental velocity in order to improve the accuracy of system. Then, in order to implement the new strapdown algorithm in a single FPGA chip, the parallelization of the algorithm is designed and its computational complexity is analyzed. The performance of the proposed parallel strapdown algorithm is tested on the Xilinx ISE 12.3 software platform and the FPGA device XC6VLX550T hardware platform on the basis of some fighter data. It is shown that this parallel strapdown algorithm on the FPGA platform can greatly decrease the execution time of algorithm to meet the real-time and high precision requirements of system on the high dynamic environment, relative to the existing implemented on the DSP platform.
Detection of Single-Nucleotide Polymorphism on uidA Gene of Escherichia coli by a Multiplexed Electrochemical DNA Biosensor with Oligonucleotide-Incorporated Nonfouling Surface
Authors: Liu Gang , Lao Ruojun , Xu Li , Xu Qin , Li Lanying , Zhang Min , Shen Hao , Mathur Sanjay , Fan Chunhai , Song Shiping
Published: August 2011

We report here a practical application of a multiplexed electrochemical DNA sensor for highly specific single-nucleotide polymorphism (SNP) detection. In this work, a 16-electrode array was applied with an oligonucleotide-incorporated nonfouling surfaces (ONS) on each electrode for the resistance of unspecific absorption. The fully matched target DNA templated the ligation between the capture probe assembled on gold electrodes and the tandem signal probe with a biotin moiety, which could be transduced to peroxidase-based catalyzed amperometric signals. A mutant site (T93G) in uidA gene of E. coli was analyzed in PCR amplicons. 10% percentage of single mismatched mutant gene was detected, which clearly proved the selectivity of the multiplexed electrochemical DNA biosensor when practically applied.
A Noise-Aware Coding Scheme for Texture Classification
Authors: Shoyaib Mohammad , Abdullah-Al-Wadud M. , Chae Oksam
Published: August 2011

Texture-based analysis of images is a very common and much discussed issue in the fields of computer vision and image processing. Several methods have already been proposed to codify texture micro-patterns (texlets) in images. Most of these methods perform well when a given image is noise-free, but real world images contain different types of signal-independent as well as signal-dependent noises originated from different sources, even from the camera sensor itself. Hence, it is necessary to differentiate false textures appearing due to the noises, and thus, to achieve a reliable representation of texlets. In this proposal, we define an adaptive noise band (ANB) to approximate the amount of noise contamination around a pixel up to a certain extent. Based on this ANB, we generate reliable codes named noise tolerant ternary pattern (NTTP) to represent the texlets in an image. Extensive experiments on several datasets from renowned texture databases, such as the Outex and the Brodatz database, show that NTTP performs much better than the state-of-the-art methods.