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Selected AbstractsRushing for Gold: Mobility and Small-Scale Mining in East AfricaDEVELOPMENT AND CHANGE, Issue 2 2009Jesper Bosse Jřnsson ABSTRACT African rural dwellers have faced depressed economic prospects for several decades. Now, in a number of mineral-rich countries, multiple discoveries of gold and precious stones have attracted large numbers of prospective small-scale miners. While their ,rush' to, and activities within, mining sites are increasingly being noted, there is little analysis of miners' mobility patterns and material outcomes. In this article, on the basis of a sample survey and interviews at two gold-mining sites in Tanzania, we probe when and why miners leave one site in favour of another. Our findings indicate that movement is often ,rushed' but rarely rash. Whereas movement to the first site may be an adventure, movement to subsequent sites is calculated with knowledge of the many risks entailed. Miners spend considerable time at each site before migrating onwards. Those with the highest site mobility tend to be more affluent than the others, suggesting that movement can be rewarding for those willing to ,try their luck' with the hard work and social networking demands of mining another site. [source] Escherichia coli thioredoxin inhibition by cadmiumFEBS JOURNAL, Issue 7 2004Asp2, Two mutually exclusive binding sites involving Cys3 Observations of thioredoxin inhibition by cadmium and of a positive role for thioredoxin in protection from Cd2+ led us to investigate the thioredoxin,cadmium interaction properties. We used calorimetric and spectroscopic methods at different pH values to explore the relative contribution of putative binding residues (Cys32, Cys35, Trp28, Trp31 and Asp26) within or near the active site. At pH 8 or 7.5 two binding sites were identified by isothermal titration calorimetry with affinity constants of 10 × 106 m,1 and 1 × 106 m,1. For both sites, a proton was released upon Cd2+ binding. One mole of Cd2+ per mole of reduced thioredoxin was measured by mass spectrometry at these pH values, demonstrating that the two binding sites were partially occupied and mutually exclusive. Cd2+ binding at either site totally inhibited the thiol,disulfide transferase activity of Trx. The absence of Cd2+ interaction detected for oxidized or alkylated Trx and the inhibition of the enzymatic activity of thioredoxin by Cd2+ supported the role of Cys32 at the first site. The fluorescence profile of Cd2+ -bound thioredoxin differed, however, from that of oxidized thioredoxin, indicating that Cd2+ was not coordinated with Cys32 and Cys35. From FTIR spectroscopy, we inferred that the second site might involve Asp26, a buried residue that deprotonates at a rather high and unusual pKa for a carboxylate (7.5/9.2). The pKa of the two residues Cys32 and Asp26 have been shown to be interdependent [Chivers, T. P. (1997) Biochemistry36, 14985,14991]. A mechanism is proposed in which Cd2+ binding at the solvent-accessible thiolate group of Cys32 induces a decrease of the pKa of Asp26 and its deprotonation. Conversely, interaction between the carboxylate group of Asp26 and Cd2+ at a second binding site induces Cys32 deprotonation and thioredoxin inhibition, so that Cd2+ inhibits thioredoxin activity not only by binding at the Cys32 but also by interacting with Asp26. [source] Using DC resistivity tomography to detect and characterize mountain permafrostGEOPHYSICAL PROSPECTING, Issue 4 2003Christian Hauck ABSTRACT Direct-current (DC) resistivity tomography has been applied to different mountain permafrost regions. Despite problems with the very high resistivities of the frozen material, plausible results were obtained. Inversions with synthetic data revealed that an appropriate choice of regularization constraints was important, and that a joint analysis of several tomograms computed with different constraints was required to judge the reliability of individual features. The theoretical results were verified with three field experiments conducted in the Swiss and the Italian Alps. At the first site, near Zermatt, Switzerland, the location and the approximate lateral and vertical extent of an ice core within a moraine could be delineated. On the Murtel rock glacier, eastern Swiss Alps, a steeply dipping boundary at its frontal part was observed, and extremely high resistivities of several M, indicated a high ice content. The base of the rock glacier remained unresolved by the DC resistivity measurements, but it could be constrained with transient EM soundings. On another rock glacier near the Stelvio Pass, eastern Italian Alps, DC resistivity tomography allowed delineation of the rock glacier base, and the only moderately high resistivities within the rock glacier body indicated that the ice content must be lower compared with the Murtel rock glacier. [source] Ground Water Transfer Initiates Complete Reductive Dechlorination in a PCE-Contaminated AquiferGROUND WATER MONITORING & REMEDIATION, Issue 3 2007R. Lookman We conducted a field test to investigate whether ground water transfer from one site (showing complete natural reductive dechlorination of chlorinated ethenes to ethene) could induce full reductive dechlorination at another site polluted with tetrachloroethene and its partial dechlorination products trichloroethene and cis -dichloroethene (cDCE). Addition of electron donor (lactate) at the test site established low redox conditions but did not stimulate further dechlorination past cDCE. After transferring 2 m3 of ground water from the first site to the test site, full dechlorination commenced and high levels of ethene were measured to distances up to 6 m downstream of the injection location within 7 months. Ground water samples from monitoring wells were analyzed before and after inoculation of the test site for the presence of Dehalococcoides species (16S ribosomal RNA) and vinyl chloride reductase (vCRA) genes using the polymerase chain reaction. These tests showed that Dehalococcoides species were present both before and after ground water transfer, while vCRA genes were detected at the test site only after ground water transfer. The vCRA genes were detected in ground water samples collected 6 m downstream of the injection locations 7 months after ground water transfer, suggesting that the microorganisms carrying the dehalogenase genes were effectively transported in the aquifer. [source] SEASONAL GROWTH AND PHENOTYPIC VARIATION IN PORPHYRA LINEARIS (RHODOPHYTA) POPULATIONS ON THE WEST COAST OF IRELAND,JOURNAL OF PHYCOLOGY, Issue 1 2007Elena Varela-Álvarez The phenology and seasonal growth of Porphyra linearis Grev. were investigated in two morphologically dissimilar populations from the west coast of Ireland. Thallus size and reproductive status of individuals were monitored monthly between June 1997 and June 1998. Both populations exhibited a similar phenology: gametophyte stages appeared on the shore in October, with spermatangial and zygotosporangial sori appearing the following February; the gametophyte stage began to degenerate in April and had disappeared completely by June. However, significant differences in growth and reproduction in the field and in cultures of plants from the two populations were observed. Thallus length and width of individuals from one population were significantly longer throughout the sample period, and reproduction and sporulation occurred 1 month earlier. Also, in situ relative growth rates (RGRs) of plants differed significantly and were correlated with different climatic factors (sunshine, day length, irradiance, rainfall, seawater temperature, and intertidal temperatures), suggesting that plants were affected by two different microhabitats. At one site, blades were more exposed to wave action, sunshine, and extreme minimum temperatures, while at the other site, blades were more protected in winter, spring, and early summer. In culture, RGRs of blades from the second site were higher than RGRs of blades from the first site under short days, corroborating the field results and suggesting a degree of phenotypic differentiation between the two populations. However, there were no sequence divergences of the RUBISCO spacer between strains of the two P. linearis populations. [source] Enantioseparation of nuarimol by affinity electrokinetic chromatography-partial filling technique using human serum albumin as chiral selectorJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2008Maria Amparo Martínez-Gómez Abstract The present paper deals with the enantiomeric separation of nuarimol enantiomers by affinity EKC-partial filling technique using HSA as chiral selector. Firstly, a study of nuarimol interactions with HSA by CE-frontal analysis was performed. The binding parameters obtained for the first site of interaction were n1 = 0.84; K1 = 9.7 ± 0.3×103 M,1 and the protein binding percentage of nuarimol at physiological concentration of HSA was 75.2 ± 0.2%. Due to the moderate affinity of nuarimol towards HSA the possibility of using this protein as chiral selector for the separation of nuarimol using the partial filling technique was evaluated. A multivariate optimization approach of the most critical experimental variables in enantioresolution, running pH, HSA concentration and plug length was carried out. Separation of nuarimol enantiomers was obtained under the following selected conditions: electrophoretic buffer composed of 50 mM Tris at pH 7.3; 160 ,M HSA solution applied at 50 mbar for 156 s as chiral selector; nuarimol solutions in the range of 2,8×10,4 M injected hydrodynamically at 30 mbar for 2 s and the electrophoretic runs performed at 30°C applying 15 kV voltage. Resolution, accuracy, reproducibility speed and cost of the proposed method make it suitable for quality control of the enantiomeric composition of nuarimol in formulations and for further toxicological studies. The results showed a different affinity between nuarimol enantiomers towards HSA. [source] Sample survey of drug-resistant tuberculosis in Henan, China, 1996RESPIROLOGY, Issue 1 2002GUOBIN WANG Background: There is little reliable data on the global drug resistance to tuberculosis (TB) as most of the existing data is based upon biased samples, is not standardized or was obtained using poor techniques. For this reason, the World Health Organization (WHO) and the International Union Against Tuberculosis and Lung Disease (IUATLD) developed a global project on anti-TB drug resistance surveillance (DRS) in 1994. China joined this project in 1995 and the province of Henan was selected as the first site for collection of representative samples to survey the prevalence of drug-resistant TB. Methodology: Standard drug susceptibility testing by the proportion method against streptomycin (S), isoniazid (H), rifampicin (R), and ethambutol (E) was performed with Mycobacterium tuberculosis isolated from 916 new cases and 456 previously treated cases. Treatment outcome of these patients has been evaluated according to the regimens and drug susceptibility patterns. Results: Drug resistance among new cases to any drug was found to be 43.0% and any resistance: S, 32.5%; H, 31.0%; R, 20.7%; and E, 10.3%. Drug resistance among previously treated cases to any drug was 68.2% and any resistance: S, 52.2%; H, 49.3%; R, 48.3%; and E, 20.4%. The cure rate for new cases was 43.3% and 29.4% for previously treated cases. The poor cure rate resulted mainly from a high defaulter rate. Conclusion: Drug-resistant TB was found to be highly prevalent in Henan and the cure rate remained poor. The results strongly indicated that Henan should take immediate action to improve the cure rate of patients through expansion of the introduction of the directly observed treatment short-course strategy. [source] 1140915445 Increased numbers of FoxP3+ cells in vaginal mucus from normal pregnant mice suggest early antigen-specific tolerance mechanism during pregnancyAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2006C Thuere The fetal survival within the maternal uterus is thought to be due to a transient immunological tolerance, being CD4+CD25+ T regulatory cells (Tregs) crucial players. Former studies confirmed diminished total numbers of this unique population in abortion-prone mice (DBA/2J-mated CBA/J females) as compared to a control with normal pregnancy outcome (BALB/c-mated CBA/J females) and suggested that Tregs act in an antigen-specific fashion. This hypothesis led us to investigate the kinetics of Tregs during pregnancy (day 0, 2, 5, 8, 10 or 12 of pregnancy) in abortion-prone mice and the control group. Our data confirmed diminished number of Tregs in immunological relevant organs such as lymph nodes and thymus within the abortion-prone mice. The enormous augmentation in the number of FoxP3+ cells in vaginal mucus already on day 0.5 after conception, followed by increased Tregs levels at early pregnancy stages, suggest, that Tregs need to be activated by male antigens for being protective. Notably, the abortion-prone mice displayed again a lower total amount of Tregs as compared to the control. Similar progesterone levels in spite of different pregnancy outcome reinforce the theory of antigen specificity of pregnancy-induced Tregs. The antigen presentation would take place in the periphery e.g. in vaginal mucus, the first site of contact with paternal antigens, directly after insemination. Interestingly the transfer of Tregs from normal pregnant mice at this time point prevented fetal rejection. Our results suggest the crucial role of Tregs already shortly after conception. [source] ANTERIOR TONGUE CANCER: AGE IS NOT A PREDICTOR OF OUTCOME AND SHOULD NOT ALTER TREATMENTANZ JOURNAL OF SURGERY, Issue 11 2003Michael J. Veness Background: Mucosal head and neck cancers usually occur in older males after years of smoking and alcohol abuse. Despite this, approximately 5% of cases occur in young adults. The aetiology remains unclear and the anterior tongue is a prevalent site. Prognosis has been reported as worse in young patients and some have proposed a more aggressive treatment approach. Methods: Patients diagnosed with previously untreated anterior tongue squamous cell carcinoma and treated with curative intent were identified. Retrospective and prospective data were collected. Univariate and multivariate analyses were undertaken using Cox regression analysis. The outcome of patients treated with anterior tongue cancer using a cut-off age of 40 years was compared. Results: Between 1980 and 2000, 106 males and 58 females with anterior tongue squamous cell carcinoma were treated at Westmead Hospital. Median follow up was 47 months (6,210 months). Twenty-two patients (13.4%) were aged ,40 years. Other than age, patient demographics, TNM stage and treatment approach were similar between the two groups. Eighty-one per cent had either a T1 or T2 primary. In total, 139 patients (84.8%) had surgery or surgery and radiotherapy. A total of 56 (34%) patients experienced a recurrent event, with nodal recurrence occurring most often as the first site (n = 33, 59%). Young patients had a higher recurrence rate (45.5% vs 32.4%; P = 0.23). Relapse-free survival at 5 years was 62% versus 81% (P = 0.27). Overall survival at 5 years was 65% versus 67% (P = 0.74). Conclusions: In keeping with recently published evidence, young age at diagnosis with anterior tongue cancer did not portend worse outcome. There is therefore currently no strong evidence to support a different treatment approach in young patients. [source] Different Ca2+ signalling cascades manifested by mastoparan in the prothoracic glands of the tobacco hornworm, Manduca sexta, and the silkworm, Bombyx moriARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2007Skarlatos G. Dedos Abstract Application of the tetradecapeptide mastoparan to the prothoracic glands (PGs) of the tobacco hornworm, Manduca sexta, and the silkworm, Bombyx mori, resulted in increases in intracellular Ca2+ ([Ca2+]i). In M. sexta, Gi proteins are involved in the mastoparan-stimulated increase in [Ca2+]i. However, there is no involvement of Gi proteins in the mastoparan-stimulated increase in [Ca2+]i in prothoracic gland cells from B. mori. Unlike in M. sexta prothoracic glands, in B. mori prothoracic glands mastoparan increases [Ca2+]i even in the absence of extracellular Ca2+. Pharmacological manipulation of the Ca2+ signalling cascades in the prothoracic glands of both insect species suggests that in M. sexta prothoracic glands, mastoparan's first site of action is influx of Ca2+ through plasma membrane Ca2+ channels while in B. mori prothoracic glands, mastoparan's first site of action is mobilization of Ca2+ from intracellular stores. In M. sexta, the combined results indicate the presence of mastoparan-sensitive plasma membrane Ca2+ channels, distinct from those activated by prothoracicotropic hormone or the IP3 signalling cascade, that coordinate spatial increases in [Ca2+]i in prothoracic gland cells. We propose that in B. mori, mastoparan stimulates Ca2+ mobilization from ryanodine-sensitive intracellular Ca2+ stores in prothoracic gland cells. Arch. Insect Biochem. Physiol. 65:52,64, 2007. © 2007 Wiley-Liss, Inc. [source] Prospective study of bone scintigraphy as a staging investigation for oesophageal carcinoma,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2008N. A. Jennings Background: About 10 per cent of patients undergoing radical oesophagectomy for transmural (T3) carcinoma with lymph node involvement (N1) develop symptomatic bone metastases within 12 months of surgery. The aim of this study was to evaluate the introduction of targeted preoperative bone scintigraphy. Methods: Of 790 patients with oesophageal carcinoma staged between December 2000 and December 2004, 189 were eligible for potentially curative treatment. 99mTc-labelled hydroxymethylene diphosphonate bone scintigraphy was performed in those with stage T3 N1 disease (identified by computed tomography and endoscopic ultrasonography) who were suitable for radical treatment. Results: A total of 115 patients had bone scintigraphy. The histological diagnosis was adenocarcinoma in 82 patients and squamous cell carcinoma in 33. Bone scintigraphy was normal or showed degenerative changes in 93 patients, and abnormal requiring further investigation in 22. Plain radiography, magnetic resonance imaging and biopsy confirmed the presence of bone metastases in 11 patients (9·6 per cent). Conclusion: Bone is frequently the first site of identifiable distant metastatic spread, and bone scintigraphy is recommended to exclude metastatic disease before radical treatment of advanced oesophageal carcinoma. Copyright © 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Brain metastases in locally advanced nonsmall cell lung carcinoma after multimodality treatmentCANCER, Issue 3 2002Risk factors analysis Abstract BACKGROUND Brain metastases (BM) are frequent sites of initial failure in patients with locally advanced nonsmall cell lung cancer (LAD-NSCLC) undergoing multimodality treatments (MMT). New treatment and follow-up strategies are needed to reduce the risk of BM and to diagnose them early enough for effective treatment. METHODS The incidence rate of BM as the first site of recurrence in 112 patients with LAD-NSCLC treated with the same MMT protocol was calculated. The influence of patient, disease, and treatment-related factors on the incidence of BM and on the time-to-brain recurrence (TBR) was analyzed. RESULTS BM as the first site of failure was observed in 25 cases (22% of the study population and 29% of all recurrences). In 18 of those cases, the brain was the exclusive site of recurrence. Median TBR was 9 months. The 2-year actuarial incidence of BM was 29%. Central nervous system (CNS) recurrence was more common in patients younger than 60 years (P = 0.006) and in whom bulky (, 2 cm) mediastinal lymph nodes were present (P = 0.02). TBR was influenced by age (P = 0.004) and by bulky lymph node disease (P = 0.003). Multivariate analysis confirmed the prognostic role of age, whereas the presence of clinical bulky mediastinal lymph nodes was of borderline significance. CONCLUSIONS Our study confirmed a high rate of BM in patients with LAD-NSCLC submitted to MMT. Most of these CNS recurrences were isolated and occurred within 2 years of initial diagnosis. Age younger than 60 years was associated with an increased risk of BM and reduced TBR, whereas the presence of clinical bulky mediastinal lymph nodes was of borderline significance. Although our data require further validation in future studies, our results suggest that additional trials on prophylactic cranial irradiation and on intensive radiologic follow-up should focus on these high-risk populations. Cancer 2002;95:605,12. © 2002 American Cancer Society. DOI 10.1002/cncr.10687 [source] | |||||||||||||