The quest for corporate growth

Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1996.Includes bibliographical references (leaves 116-122).by Gabriel D. Obrador Ramos and Edmundo E. Ruiz Rodriguez.M.S

Fate and effects of uncoated ZnO nanoparticles on nine crops exposed in two agricultural soils, a calcareous and an acidic soil.

The nanotechnology has a wide range of applications including those that deliberately release nanoparticles (NPs) into the environment. The use of nanoformulations containing agrochemicals to soils provides an efficient way to apply pesticides and fertilizers in a controlled mode. The zinc oxide nanoparticles (ZnO NPs) are of particular interest due to their increasing incorporation into agricultural products

Toxicity of ZnO nanoparticles, ZnO bulk and ZnCl2 on earthworms in a spiked natural soil and toxicological effects of leachates on aquatic organisms

The present study assessed the uptake and toxicity of ZnO nanoparticles (NPs), ZnO bulk, and ZnCl2 salt in earthworms in spiked agricultural soils. In addition, the toxicity of aqueous extracts to Daphnia magna and Chlorella vulgaris was analyzed to determine the risk of these soils to the aquatic compartment. We then investigated the distribution of Zn in soil fractions to interpret the nature of toxicity. Neither mortality nor differences in earthworm body weight were observed compared with the control. The most sensitive end point was reproduction. ZnCl2 was notably toxic in eliminating the production of cocoons. The effects induced by ZnO-NPs and bulk ZnO on fecundity were similar and lower than those of the salt. In contrast to ZnO bulk, ZnO-NPs adversely affected fertility. The internal concentrations of Zn in earthworms in the NP group were greater than those in the salt and bulk groups, although bioconcentration factors were consistently <1. No relationship was found between toxicity and internal Zn amounts in earthworms. The results from the sequential extraction of soil showed that ZnCl2 displayed the highest availability compared with both ZnO. Zn distribution was consistent with the greatest toxicity showed by the salt but not with Zn body concentrations. The soil extracts from both ZnO-NPs and bulk ZnO did not show effects on aquatic organisms (Daphnia and algae) after short-term exposure. However, ZnCl2 extracts (total and 0.45-μm filtered) were toxic to Daphnia

Soil pH effects on the Toxicity of zinc oxide nanoparticles to soil bacterial communities.

The environmental levels of ZnO nanoparticles (nZnO) are increasing continually given the widespread and expanding applications of this material. Soil pH appears to be one of the key factors affecting the behavior and toxicity of metal nanoparticles in soi

Influence of soil pH in the effects of ZnONPs on the antioxidant activities and Zn uptake in three plant species (T aestivum, R. sativus and Z. mays)

In recent years, the study of phytotoxicity of NPs has made rapid progress, but important issues remain to be solved, among them, the role of soil and the importance of the physicochemical soil characteristics for their toxicity and accumulation potential

Glutathione and Bcl-2 targeting facilitates elimination by chemoradiotherapy of human A375 melanoma xenografts overexpressing bcl-xl, bcl-2, and mcl-1

<p>Abstract</p> <p>Background</p> <p>Bcl-2 is believed to contribute to melanoma chemoresistance. However, expression of Bcl-2 proteins may be different among melanomas. Thus correlations among expression of Bcl-2-related proteins and <it>in vivo </it>melanoma progression, and resistance to combination therapies, was investigated.</p> <p>Methods</p> <p>Human A375 melanoma was injected s.c. into immunodeficient nude mice. Protein expression was studied in tumor samples obtained by laser microdisection. Transfection of siRNA or ectopic overexpression were applied to manipulate proteins which are up- or down-regulated, preferentially, during melanoma progression. Anti-<it>bcl</it>-2 antisense oligonucleotides and chemoradiotherapy (glutathione-depleting agents, paclitaxel protein-binding particles, daunorubicin, X rays) were administered in combination.</p> <p>Results</p> <p><it>In vivo </it>A375 cells down-regulated pro-apoptotic <it>bax </it>expression; and up-regulated anti-apoptotic <it>bcl-2</it>, <it>bcl-xl</it>, and <it>mcl-1</it>, however only Bcl-2 appeared critical for long-term tumor cell survival and progression <it>in vivo</it>. Reduction of Bcl-2, combined with partial therapies, decreased melanoma growth. But only Bcl-2 targeting plus the full combination of chemoradiotherapy eradicated A375 melanoma, and led to long-term survival (> 120 days) without recurrence in 80% of mice. Tumor regression was not due to immune stimulation. Hematology and clinical chemistry data were within accepted clinical toxicities.</p> <p>Conclusion</p> <p>Strategies to target Bcl-2, may increase the effectiveness of antitumor therapies against melanomas overexpressing Bcl-2 and likely other Bcl-2-related antiapoptotic proteins.</p

Recurs multimedia del treball de camp en geologia

El portal Geocamp s'ha creat per aplicar-lo al procés d'aprenentatge de la Geologia al camp, enllaçant conceptes teòrics amb metodologia de treball fora de l'aula o el laboratori. S'adreça a docents i estudiants d'universitat, secundària, batxillerat, formació de professorat o públic en general. Aquest portal conté materials didàctics propis i enllaços amb tot tipus d'informacions relatives al treball de camp en Ciències de la Terra. L'element més innovador rau en la seva utilitat a l'hora de plantejar les activitats de preparació de les excursions. També hi trobem pautes metodològiques per a treballar en els afloraments, idees sobre les activitats de síntesi etc. Geocamp consta de 4 blocs: "Preparem la sortida" (elecció del lloc, transport, predicció meteorològica, material necessari, materials didàctics, enllaços d'interès etc.), "El treball de camp" (pautes d'observació, descripció i interpretació de les roques, recomanacions de seguretat etc.), "Itineraris" (exemples regionals propis o disponibles a la xarxa) i "Després de la sortida" (propostes de realització d'un informe final etc.)

Seizure-related 6 homolog like 2 autoimmunity: Neurologic syndrome and antibody effects

Objective: To describe the clinical syndrome of 4 new patients with seizure-related 6 homolog like 2 antibodies (SEZ6L2-abs), study the antibody characteristics, and evaluate their effects on neuronal cultures. Methods: SEZ6L2-abs were initially identified in serum and CSF of a patient with cerebellar ataxia by immunohistochemistry on rat brain sections and immunoprecipitation from rat cerebellar neurons. We used a cell-based assay (CBA) of HEK293 cells transfected with SEZ6L2 to test the serum of 95 patients with unclassified neuropil antibodies, 331 with different neurologic disorders, and 10 healthy subjects. Additional studies included characterization of immunoglobulin G (IgG) subclasses and the effects of SEZ6L2-abs on cultures of rat hippocampal neurons. Results: In addition to the index patient, SEZ6L2-abs were identified by CBA in 3/95 patients with unclassified neuropil antibodies but in none of the 341 controls. The median age of the 4 patients was 62 years (range: 54-69 years), and 2 were female. Patients presented with subacute gait ataxia, dysarthria, and mild extrapyramidal symptoms. Initial brain MRI was normal, and CSF pleocytosis was found in only 1 patient. None improved with immunotherapy. SEZ6L2-abs recognized conformational epitopes. IgG4 SEZ6L2-abs were found in all 4 patients, and it was the predominant subclass in 2. SEZ6L2-abs did not alter the number of total or synaptic SEZ6L2 or the AMPA glutamate receptor 1 (GluA1) clusters on the surface of hippocampal neurons. Conclusions: SEZ6L2-abs associate with a subacute cerebellar syndrome with frequent extrapyramidal symptoms. The potential pathogenic effect of the antibodies is not mediated by internalization of the antigen

Validation of a core patient-reported outcome measure for fatigue in patients receiving hemodialysis: The SONG-HD fatigue instrument

Background and objectives Fatigue is a very common and debilitating symptom and identified by patients as a critically important core outcome to be included in all trials involving patients receiving hemodialysis. A valid, standardized measure for fatigue is needed to yield meaningful and relevant evidence about this outcome. This study validated a core patient-reported outcome measure for fatigue in hemodialysis. Design, setting, participants, &amp; measurements A longitudinal cohort study was conducted to assess the validity and reliability of a new fatigue measure (Standardized Outcomes in Nephrology-Hemodialysis Fatigue [SONGHD Fatigue]). Eligible and consenting patients completed the measure at three time points: baseline, a week later, and 12 days following the second time point. Cronbach α and intraclass correlation coefficient were calculated to assess internal consistency, and Spearman rho was used to assess convergent validity. Confirmatory factor analysis was also conducted. Hemodialysis units in the United Kingdom, Australia, and Romania participated in this study. Adult patients aged 18 years and over who were English speaking and receiving maintenance hemodialysis were eligible to participate. Standardized Outcomes in Nephrology-Hemodialysis, the Visual Analog Scale for fatigue, the 12-Item Short Form Survey, and Functional Assessment of Chronic Illness Therapy–Fatigue were used. Results In total, 485 participants completed the study across the United Kingdom, Australia, and Romania. Psychometric assessment demonstrated that Standardized Outcomes in Nephrology-Hemodialysis is internally consistent (Cronbach α =0.81–0.86) and stable over a 1-week period (intraclass correlation coefficient =0.68–0.74). The measure demonstrated convergence with Functional Assessment of Chronic Illness Therapy–Fatigue and had moderate correlations with other measures that assessed related but not the same concept (the 12-Item Short Form Survey and the Visual Analog Scale). Confirmatory factor analysis supported the one-factor model. Conclusions SONG-HD Fatigue seems to be a reliable and valid measure to be used in trials involving patients receiving hemodialysis

Aggressive Course in Encephalitis With Opsoclonus, Ataxia, Chorea, and Seizures. The First Pediatric Case of γ-Aminobutyric Acid Type B Receptor Autoimmunity

IMPORTANCE: Autoantibodies to the γ-aminobutyric acid type B (GABAB) receptor have recently been identified as a cause of autoimmune encephalitis. Most patients with GABAB encephalitis have presented with limbic encephalitis. About half of the cases reported have been paraneoplastic in origin, with the majority of tumors representing small cell lung cancer. OBSERVATIONS: We describe a 3-year-old boy who presented with a mixed movement disorder (opsoclonus, ataxia, and chorea) as well as seizures refractory to treatment. His seizures required continuous pentobarbital sodium infusion to be controlled. Despite treatment with intravenous corticosteroids and immunoglobulins, the patient ultimately died of overwhelming sepsis. CONCLUSIONS AND RELEVANCE: To our knowledge, this report represents the first pediatric case of GABAB-associated encephalitis. Our patient presented with encephalopathy, refractory seizures, and a mixed movement disorder rather than limbic encephalitis. γ-Aminobutyric acid type B receptor autoimmunity deserves consideration in pediatric patients presenting with encephalitis. Immune-mediated encephalitis with autoantibodies directed against synaptic proteins has become an important component of the differential diagnosis of patients with encephalitis. Current estimates suggest that a substantial proportion of patients once suspected to have viral encephalitis in fact have an autoimmune etiology for their symptoms.1 Additional autoantigen targets continue to be identified, and the phenotypic spectrum associated with autoimmune encephalitis continues to expand. We describe a 3-year-old patient who presented with acute-onset confusion, opsoclonus, chorea, and intractable seizures. Neuroimaging disclosed involvement of the brainstem, basal ganglia, and hippocampi. γ-Aminobutyric acid type B (GABAB) receptor autoantibodies were identified in the serum and cerebrospinal fluid (CSF). Despite immunomodulating therapy, the patient died of overwhelming sepsis. To our knowledge, this is the first description of a pediatric patient with GABAB receptor autoantibodies. The presence of opsoclonus, ataxia, and chorea expands the clinical phenotype and indicates that GABAB receptor autoimmunity should be considered in cases of pediatric encephaliti