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

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

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

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.)

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

Wnt signalling in adenomas of familial adenomatous polyposis patients

BACKGROUND: Epigenetic silencing of Wnt antagonists and expression changes in genes associated with Wnt response pathways occur in early sporadic colorectal tumourigenesis, indicating that tumour cells are more sensitive to Wnt growth factors and respond differently. In this study, we have investigated whether similar changes occur in key markers of the Wnt response pathways in the genetic form of the disease, familial adenomatous polyposis (FAP). METHODS: We investigated epigenetic and expression changes using pyrosequencing and real-time RT-PCR in samples from seven patients without neoplasia, and matched normal and tumour tissues from 22 sporadic adenoma and 14 FAP patients. RESULTS: We found that 17 out of 24 (71%) FAP adenomas were hypermethylated at sFRP1, compared with 20 out of 22 (91%) of sporadic cases. This was reflected at the level of sFRP1 transcription, where 73% of FAP and 100% of sporadic cases were downregulated. Increased expression levels of c-myc and FZD3 were less common in FAP (35 and 46% respectively) than sporadic tumours (78 and 67% respectively). CONCLUSION: Overall, the changes in expression and methylation were comparable, although the degree of change was generally lower in the FAP adenomas. Molecular heterogeneity between multiple adenomas from individual FAP patients may reflect different developmental fates for these premalignant tumours

Active collaboration with primary care providers increases specialist referral in chronic renal disease

BACKGROUND: Late referral to specialist nephrological care is associated with increased morbidity, mortality, and cost. Consequently, nephrologists' associations recommend early referral. The recommendations' effectiveness remains questionable: 22–51% of referrals need renal replacement therapy (RRT) within 3–4 months. This may be due to these recommendations addressing the specialist, rather than the primary care providers (PCP). The potential of specialist intervention aiming at slowing progression of chronic renal failure was introduced individually to some 250 local PCPs, and referral strategies were discussed. To overcome the PCPs' most often expressed fears, every referred patient was asked to report back to his PCP immediately after the initial specialist examination, and new medications were prescribed directly, and thus allotted to the nephrologist's budget. METHODS: In retrospective analysis, the stage of renal disease in patients referred within three months before the introductory round (group A, n = 18), was compared to referrals two years later (group B, n = 50). RESULTS: Relative number of patients remained stable (28%) for mild/ moderate chronic kidney disease (MMCKD), while there was a noticeable shift from patients referred severe chronic kidney disease (SCKD) (group A: 44%, group B: 20%) to patients referred in moderate chronic kidney disease (MCKD) (group A: 28%, group B: 52%). CONCLUSION: Individually addressing PCPs' ignorance and concerns noticeably decreased late referral. This stresses the importance of enhancing the PCPs' problem awareness and knowledge of available resources in order to ensure timely specialist referral