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1.
J Environ Radioact ; 226: 106354, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33046265

RESUMO

Tritium, the radioactive isotope of hydrogen, has been used to understand groundwater recharge processes for decades. The current variation of tritium in the atmosphere is largely attributed to stratospheric production and fall out rates as well as global circulation phenomena controlling the hydrological cycle. Global controls on the variability in atmospheric tritium activity are poorly suited to explain local variation and tritium activities in precipitation are often assumed to be uniform over both local and regional catchments and watersheds. This assumption can result in both over and under estimation of modern recharge within an aquifer when using tritium as the recharge proxy. In order to minimize the inherent prediction residuals associated with tritium based recharge investigations, the variability of tritium in precipitation was modelled from 127 spatial precipitation samples taken over a two year period, combined with a 76 precipitation sample group-set taken over a one year period in a single location. Precipitation events were traced backward in time, from the point of collection, using HYSPLIT modelling to ascertain the origins of moisture content as well as the altitudes of moisture origin reached along the particle track. Tritium activities, collected over a one year period in Paarl, range from 0.45 to 4.16 TU and have a mean of 1.59 TU. Spatial storm events in the Western Cape in 2017 and 2018 had a range from 0 to 2.2 and 0.37 to 3.27 TU, respectively, with mean activities of 1.18 (n = 34) and 1.25 TU (n = 32). Both storm events had similar tritium variability (σ = 0.5 n = 35 and 0.48 n = 32). Regional precipitation events had the largest range of tritium activities (0.55-12.2 TU). Although not all tritium activities can be explained by interrogating the water mass origin, this study suggests that approximately 90% of events can be completely or partially attributed to the origin of the water mass. The variability of tritium, both spatially and temporally, was higher than expected, confirming that when uniform tritium inputs are used, the groundwater system would provide inaccurate modern recharge estimates. Higher spatial resolution of tritium variation in precipitation for a particular region will improve our ability to relate tritium activities in groundwater to local precipitation.


Assuntos
Monitoramento de Radiação , Trítio/análise , Água Subterrânea , Hidrologia , África do Sul
2.
Sci Total Environ ; : 143140, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33131834

RESUMO

Namaqualand, South Africa, is a global biodiversity hotspot but local populations are affected by challenging economic conditions largely because of poor access to water. In this study groundwater types are characterised and sources of salts and salinisation processes are identified using hydrochemistry and δ18O, δ2H and 87Sr/86Sr data. Analysis of δ18O and δ2H data suggests that evaporation does not play a major role in salinisation of the groundwater. However, major ion chemistry and 87Sr/86Sr ratios indicate that salts present in the groundwater are linked to dry deposition of marine aerosols and ion-exchange reactions in soils in the alluvial aquifer systems. The hydrochemical variability of the groundwater in the basement aquifer system suggests that there are strong local controls linked to weathering processes in individual basement rock types. The region is also notable for the high density of heuweltjies, biophysical features associated with increased nutrient levels, associated with termite activity. Electromagnetic scanning as well as measurement of water-soluble soil electrical conductivity values on and off heuweltjies, show that heuweltjies are saline with salinity increasing with depth. The level of groundwater salinity correlates with the level of heuweltjie salinity. Precipitation records from the last 150 years provide support for the hypothesis that accumulated salts, and in particular, heuweltjie salts are flushed into the groundwater system during sporadic large volume precipitation events. Thus, heuweltjies and hence termite activity, could potentially represent a previously unrecognized contributor to groundwater salinisation across Namaqualand and in other parts of the world.

3.
J Mech Behav Biomed Mater ; 110: 103956, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32957249

RESUMO

BACKGROUND: One of the major causes of pelvic organ prolapse is pelvic muscle injury sustained during a vaginal delivery. The most common site of this injury is where the pubovisceral muscle takes origin from the pubic bone. We hypothesized that it is possible for low-cycle material fatigue to occur at the origin of the pubovisceral muscle under the large repetitive loads associated with pushing during the second stage of a difficult labor. PURPOSE: The main goal was to test if the origin of the pubovisceral muscle accumulates material damage under sub-maximal cyclic tensile loading and identify any microscopic evidence of such damage. METHODS: Twenty origins of the ishiococcygeous muscle (homologous to the pubovisceral muscle in women) were dissected from female sheep pelvises. Four specimens were stretched to failure to characterize the failure properties of the specimens. Thirteen specimens were then subjected to relaxation and subsequent fatigue tests, while three specimens remained as untested controls. Histology was performed to check for microscopic damage accumulation. RESULTS: The fatigue stress-time curves showed continuous stress softening, a sign of material damage accumulation. Histology confirmed the presence of accumulated microdamage in the form of kinked muscle fibers and muscle fiber disruption in the areas with higher deformation, namely in the muscle near the musculotendinous junction. CONCLUSIONS: The origin of ovine ishiococcygeous muscle can accumulate damage under sub-maximal repetitive loading. The damage appears in the muscle near the musculotendinous junction and was sufficient to negatively affect the macroscopic mechanical properties of the specimens.

4.
Br J Surg ; 107(2): e170-e178, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31903598

RESUMO

BACKGROUND: Surgery for catecholamine-producing tumours can be complicated by intraoperative and postoperative haemodynamic instability. Several perioperative management strategies have emerged but none has been evaluated in randomized trials. To assess this issue, contemporary perioperative management and outcome data from 21 centres were collected. METHODS: Twenty-one centres contributed outcome data from patients who had surgery for phaeochromocytoma and paraganglioma between 2000 and 2017. The data included the number of patients with and without α-receptor blockade, surgical and anaesthetic techniques, complications and perioperative mortality. RESULTS: Across all centres, data were reported on 1860 patients with phaeochromocytoma or paraganglioma, of whom 343 underwent surgery without α-receptor blockade. The majority of operations (78·9 per cent) were performed using minimally invasive techniques, including 16·1 per cent adrenal cortex-sparing procedures. The cardiovascular complication rate was 5·0 per cent overall: 5·9 per cent (90 of 1517) in patients with preoperative α-receptor blockade and 0·9 per cent (3 of 343) among patients without α-receptor blockade. The mortality rate was 0·5 per cent overall (9 of 1860): 0·5 per cent (8 of 517) in pretreated and 0·3 per cent (1 of 343) in non-pretreated patients. CONCLUSION: There is substantial variability in the perioperative management of catecholamine-producing tumours, yet the overall complication rate is low. Further studies are needed to better define the optimal management approach, and reappraisal of international perioperative guidelines appears desirable.


Assuntos
Neoplasias das Glândulas Suprarrenais/cirurgia , Paraganglioma/cirurgia , Assistência Perioperatória/métodos , Feocromocitoma/cirurgia , Padrões de Prática Médica/estatística & dados numéricos , Adrenalectomia/métodos , Adrenalectomia/mortalidade , Antagonistas Adrenérgicos alfa/uso terapêutico , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Assistência Perioperatória/mortalidade , Resultado do Tratamento
6.
J Perinatol ; 37(7): 875-880, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28383538

RESUMO

OBJECTIVE: To assess long-term outcomes of children with symptomatic congenital cytomegalovirus (CMV) disease detected at birth. STUDY DESIGN: We used Cox regression to assess risk factors for intellectual disability (intelligence quotient <70), sensorineural hearing loss (SNHL; hearing level ⩾25 dB in any audiometric frequency) and vision impairment (best corrected visual acuity >20 or based on ophthalmologist report). RESULTS: Among 76 case-patients followed through median age of 13 (range: 0-27) years, 56 (74%) had SNHL, 31 (43%, n=72) had intellectual disability and 18 (27%, n=66) had vision impairment; 28 (43%, n=65) had intellectual disability and SNHL with/without vision impairment. Microcephaly was significantly associated with each of the three outcomes. Tissue destruction and dysplastic growth on head computed tomography scan at birth was significantly associated with intellectual disability and SNHL. CONCLUSION: Infants with symptomatic congenital CMV disease may develop moderate to severe impairments that were associated with presence of microcephaly and brain abnormalities.


Assuntos
Encéfalo/anormalidades , Infecções por Citomegalovirus/congênito , Infecções por Citomegalovirus/complicações , Deficiência Intelectual/epidemiologia , Microcefalia/diagnóstico por imagem , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Criança , Pré-Escolar , Infecções por Citomegalovirus/fisiopatologia , Feminino , Georgia , Perda Auditiva Neurossensorial/epidemiologia , Humanos , Lactente , Recém-Nascido , Estudos Longitudinais , Masculino , Análise Multivariada , Modelos de Riscos Proporcionais , Fatores de Risco , Tomografia Computadorizada por Raios X , Transtornos da Visão/epidemiologia , Adulto Jovem
7.
Ann Rheum Dis ; 76(5): 862-868, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28122761

RESUMO

OBJECTIVES: Autoantibodies directed against cytosolic 5'-nucleotidase 1A have been identified in many patients with inclusion body myositis. This retrospective study investigated the association between anticytosolic 5'-nucleotidase 1A antibody status and clinical, serological and histopathological features to explore the utility of this antibody to identify inclusion body myositis subgroups and to predict prognosis. MATERIALS AND METHODS: Data from various European inclusion body myositis registries were pooled. Anticytosolic 5'-nucleotidase 1A status was determined by an established ELISA technique. Cases were stratified according to antibody status and comparisons made. Survival and mobility aid requirement analyses were performed using Kaplan-Meier curves and Cox proportional hazards regression. RESULTS: Data from 311 patients were available for analysis; 102 (33%) had anticytosolic 5'-nucleotidase 1A antibodies. Antibody-positive patients had a higher adjusted mortality risk (HR 1.89, 95% CI 1.11 to 3.21, p=0.019), lower frequency of proximal upper limb weakness at disease onset (8% vs 23%, adjusted OR 0.29, 95% CI 0.12 to 0.68, p=0.005) and an increased prevalence of excess of cytochrome oxidase deficient fibres on muscle biopsy analysis (87% vs 72%, adjusted OR 2.80, 95% CI 1.17 to 6.66, p=0.020), compared with antibody-negative patients. INTERPRETATION: Differences were observed in clinical and histopathological features between anticytosolic 5'-nucleotidase 1A antibody positive and negative patients with inclusion body myositis, and antibody-positive patients had a higher adjusted mortality risk. Stratification of inclusion body myositis by anticytosolic 5'-nucleotidase 1A antibody status may be useful, potentially highlighting a distinct inclusion body myositis subtype with a more severe phenotype.


Assuntos
5'-Nucleotidase/imunologia , Autoanticorpos/sangue , Fibras Musculares Esqueléticas/patologia , Miosite de Corpos de Inclusão/sangue , Miosite de Corpos de Inclusão/diagnóstico , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Citosol , Complexo IV da Cadeia de Transporte de Elétrons/análise , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Fibras Musculares Esqueléticas/química , Debilidade Muscular/etiologia , Miosite de Corpos de Inclusão/patologia , Prognóstico , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Equipamentos de Autoajuda/estatística & dados numéricos , Taxa de Sobrevida , Fatores de Tempo
8.
Acta Biomater ; 48: 300-308, 2017 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-27793720

RESUMO

This paper investigates the effects of moisture, anisotropy, stress state, and strain rate on the mechanical properties of the bighorn sheep (Ovis Canadensis) horn keratin. The horns consist of fibrous keratin tubules extending along the length of the horn and are contained within an amorphous keratin matrix. Samples were tested in the rehydrated (35wt% water) and ambient dry (10wt% water) conditions along the longitudinal and radial directions under tension and compression. Increased moisture content was found to increase ductility and decrease strength, as well as alter the stress state dependent nature of the material. The horn keratin demonstrates a significant strain rate dependence in both tension and compression, and also showed increased energy absorption in the hydrated condition at high strain rates when compared to quasi-static data, with increases of 114% in tension and 192% in compression. Compressive failure occurred by lamellar buckling in the longitudinal orientation followed by shear delamination. Tensile failure in the longitudinal orientation occurred by lamellar delamination combined with tubule pullout and fracture. The structure-property relationships quantified here for bighorn sheep horn keratin can be used to help validate finite element simulations of ram's impacting each other as well as being useful for other analysis regarding horn keratin on other animals. STATEMENT OF SIGNIFICANCE: The horn of the bighorn sheep is an anisotropic composite composed of keratin that is highly sensitive to moisture content. Keratin is also found in many other animals in the form of hooves, claws, beaks, and feathers. Only one previous study contains high rate experimental data, which was performed in the dry condition and only in compression. Considering the bighorn sheep horns' protective role in high speed impacts along with the moisture and strain rate sensitivity, more high strain rate data is needed to fully characterize and model the material. This study provides high strain rate results demonstrating the effects of moisture, anisotropy, and stress state. As a result, the comprehensive data allows modeling efforts to be greatly improved.


Assuntos
Cornos/química , Umidade , Queratinas/química , Estresse Mecânico , Animais , Anisotropia , Fenômenos Biomecânicos , Força Compressiva , Cornos/ultraestrutura , Processamento de Imagem Assistida por Computador , Carneiro da Montanha , Estatística como Assunto , Resistência à Tração
10.
Int Urogynecol J ; 25(7): 873-81, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24474605

RESUMO

OBJECTIVES: To develop and test a method for measuring the relationship between the rise in intra-abdominal pressure and sagittal plane movements of the anterior and posterior vaginal walls during Valsalva in a pilot sample of women with and without prolapse. METHODS: Mid-sagittal MRI images were obtained during Valsalva while changes in intra-abdominal pressure were measured via a bladder catheter in 5 women with cystocele, 5 women with rectocele, and 5 controls. The regional compliance of the anterior and posterior vagina wall support systems were estimated from the ratio of displacement (mm) of equidistant points along the anterior and posterior vaginal walls to intra-abdominal pressure rise (mmHg). RESULTS: The compliance of both anterior and posterior vaginal wall support systems varied along different regions of vaginal wall for all three groups, with the highest compliance found near the vaginal apex and the lowest near the introitus. Women with cystocele had more compliant anterior and posterior vaginal wall support systems than women with rectocele. The movement direction differs between cystocele and rectocele. In cystocele, the anterior vaginal wall moves mostly toward the vaginal orifice in the upper vagina, but in a ventral direction in the lower vagina. In rectocele, the direction of the posterior vaginal wall movement is generally toward the vaginal orifice. CONCLUSIONS: Movement of the vaginal wall and compliance of its support is quantifiable and was found to vary along the length of the vagina. Compliance was greatest in the upper vagina of all groups. Women with cystocele demonstrated the most compliant vaginal wall support.


Assuntos
Abdome/fisiologia , Complacência (Medida de Distensibilidade)/fisiologia , Cistocele/fisiopatologia , Retocele/fisiopatologia , Vagina/fisiologia , Adulto , Idoso , Feminino , Humanos , Imagem por Ressonância Magnética , Manometria , Pessoa de Meia-Idade , Movimento/fisiologia , Pressão , Manobra de Valsalva/fisiologia
11.
Int Urogynecol J ; 24(9): 1421-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23640002

RESUMO

Five midsagittal pelvic reference lines have been employed to quantify prolapse using MRI. However, the lack of standardization makes study results difficult to compare. Using MRI scans from 149 women, we demonstrate how use of existing reference lines can systematically affect measurements in three distinct ways: in oblique line systems, distances measured to the reference line vary with antero-posterior location; soft issue-based reference lines can underestimate organ movement relative to the pelvic bones; and systems defined relative to the MR scanner are affected by intra- and interindividual differences in the pelvic inclination angle at rest and strain. Thus, we propose a standardized approach called the Pelvic Inclination Correction System (PICS). Based on bony structures and the body axis, the PICS system corrects for variation in pelvic inclination, at rest of straining, and allows for the standardized measurement of organ displacement in the direction of prolapse.


Assuntos
Imagem por Ressonância Magnética/normas , Ossos Pélvicos/patologia , Diafragma da Pelve/patologia , Prolapso de Órgão Pélvico/diagnóstico , Prolapso de Órgão Pélvico/patologia , Colo do Útero/patologia , Feminino , Humanos , Variações Dependentes do Observador , Padrões de Referência , Reprodutibilidade dos Testes
12.
Eur J Trauma Emerg Surg ; 39(6): 599-603, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26815543

RESUMO

PURPOSE: The American College of Surgeons Committee on Trauma (ACS-COT) has determined that a 5 % pre-hospital undertriage [UT; defined as Injury Severity Score (ISS) > 15 and not sent to a trauma center] is an acceptable rate for pre-hospital transfer to a non-trauma center. We sought to determine if this level of undertriage is acceptable within a mature Level II trauma center as a measure of the adequacy of its trauma activation system. METHODS: Our trauma activation system encompasses anatomic, physiologic, and mechanism of injury criteria. We defined UT as ISS > 15 and no trauma activation. All UT patients during the period 2000-2010 were compared to properly triaged patients (CT). The variables examined were mortality, emergency department (ED) length of stay (LOS), hospital LOS, complications, Coumadin use, and age >64 years. RESULTS: There were 18,324 patients admitted, with 1,156 (6.3 %) UT. UT is associated with an increase in mortality [odds ratio (OR) 3.0; 95 % confidence interval (CI) 2.4-3.8; p < 0.001), longer ED LOS (OR 54.5; 95 % CI 45.5-63.5; p < 0.001), and longer hospital LOS (OR 1.7; 95 % CI 1.4-2.1; p < 0.001). In addition, UT patients had a two-fold increase in complications (OR 2.0; 95 % CI 1.6-2.5; p < 0.001). When controlling for age ≥65 years, Revised Trauma Score (RTS) > 7.0, and one or more co-morbidities, UT patients had 2.18 times higher odds of mortality than their CT counterparts (OR 2.18; 95 % CI 1.57-3.01; p < 0.001). Patients on pre-hospital Coumadin (OR 3.61; 95 % CI 3.04-4.30; p < 0.001) and age >64 years (OR 4.93; 95 % CI 4.36-5.58; p < 0.001) were significant predictors of being undertriaged. A p-value ≤ 0.05 was considered to be significant. CONCLUSIONS: Standard trauma activation criteria may not be adequate to identify the at-risk severely injured trauma patient. Further refinement of in-house trauma triage protocols is necessary if trauma centers are to improve outcomes following trauma.

13.
J Econ Entomol ; 105(6): 2207-12, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23356088

RESUMO

Over a 7 yr period, we monitored the effect of a commercially available, amitraz impregnated anti-tick collar in controlling free-living populations of lone star ticks, Amblyomma americanum (L.) when manually fitted around necks of white-tailed deer, Odocoileus virginianus (Zimmermann). Study animals in treatment and control groups were confined in 38.8 ha game-fenced and densely vegetated treatment plots in South Texas. Tick densities during years 1 and 7 served as untreated pre- and posttreatment comparisons and treatments occurred during years 2 through 5. Reductions in tick densities in the treatment plot were compared against tick densities in a control plot having similar vegetation and numbers of untreated deer. During years of treatment, indices of control pressure ranged from 18.2 to 82.6 for nymphs and 16.9-78.7 for adults, and efficacy, expressed as percentage control during the final year of treatment, was 77.2 and 85.0%, respectively, for nymphal and adult ticks. These data show that acaricidal collar treatments provide efficacies very similar to those achieved with the existing ivermectin-medicated bait and '4-Poster' topical treatment technologies to control ticks feeding on wild white-tailed deer.


Assuntos
Cervos/parasitologia , Repelentes de Insetos/administração & dosagem , Ixodidae , Controle de Ácaros e Carrapatos , Toluidinas/administração & dosagem , Animais , Densidade Demográfica
14.
J Econ Entomol ; 102(2): 804-8, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19449664

RESUMO

A gel formulation formed by incorporating technical doramectin into a 10% hydroxypropyl methylcellulose aqueous solution was used to subcutaneously inject steers at varying dosages. Doramectin serum concentration of steers receiving 600 microg (AI)/kg body weight declined from 21.9 ppb at 0.5 wk to below detectable at 8 wk postinjection. The 1,200 microg (AI)/kg injection resulted in serum concentrations of 29.1 ppb at 0.5 wk and declined to 0.5 ppb at 8 wk postinjection. Both the 600 and 1,200 microg (AI)/kg injections provided 100% inhibition of index of fecundity (IF) in adult lone star ticks, Amblyomma americanum L. (Acari: Ixodidae) through week 8, after which inhibition declined to 79.4 and 45.3%, respectively, during the 12th week posttreatment. For steers treated at 600 microg (AI)/kg, mortality of adult horn flies, Hematobia irritans L. (Diptera: Muscidae), declined from 16.9% during week 2 to 3.1% during week 7 postinjection. The blood from steers treated at 1,200 microg (AI)/kg resulted in a similar decline in mortality of blood fed adult horn flies from 29.4% during week 1 to 4.0% during week 7. The 600 microg (AI)/kg treatment provided complete control of larval horn flies in the manure for 9 wk, whereas the 1,200 microg (AI)/kg injection gave complete control for 14 wk posttreatment. The doramectin gel formulation provided long-lasting delivery of doramectin to cattle and extended control of lone star ticks and larval horn flies. Such a simple and inexpensive formulation could be useful in tick eradication programs by reducing the frequency of gathering cattle.


Assuntos
Doenças dos Bovinos/prevenção & controle , Ivermectina/análogos & derivados , Ixodidae/efeitos dos fármacos , Muscidae/efeitos dos fármacos , Miíase/veterinária , Infestações por Carrapato/veterinária , Animais , Bovinos , Preparações de Ação Retardada , Relação Dose-Resposta a Droga , Géis , Injeções Subcutâneas , Inseticidas/administração & dosagem , Inseticidas/farmacologia , Ivermectina/administração & dosagem , Ivermectina/farmacologia , Miíase/prevenção & controle , Infestações por Carrapato/prevenção & controle , Tempo
15.
J Econ Entomol ; 102(2): 809-14, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19449665

RESUMO

Steers were treated with doramectin or eprinomectin by daily oral capsule for 28 consecutive days. The level of doramectin in the serum of steers treated at 200 microg/kg/d reached a maximum of 104.0 +/- 22.1 ppb at day 21 and declined from 93.3 +/- 20.5 ppb on the final day of treatment to below detectable by day 56. Steers treated at 50 microg/kg/d reached a maximum level of doramectin in the serum of 24.7 +/- 1.2 ppb on day 21 and declined from 24.7 +/- 0.6 ppb on the final day of treatment to less than detectable on day 42. Both doramectin dosages provided 100% control of estimated larvae (EL) of Amblyomma americanum (L.) (Acari: Ixodidae) throughout the 28-d treatment period. Daily oral treatment with eprinomectin at a dosage of 200 microg/kg for 28 consecutive days produced a maximum concentration in the serum of 41.6 +/- 11.0 ppb at day 14. On the final day of eprinomectin treatment, the serum concentration was 38.3 +/- 5.9 ppb. Seven days later at day 35, eprinomectin was not detectable in the serum. For steers treated at 50 microg/kg/d for 28 consecutive days, the serum level of eprinomectin reached a maximum of 10.0 +/- 3.0 ppb on day 28 and was undetectable on day 35. Both eprinomectin dosages provided complete control of EL of A. americanum during the 28-d treatment period. Because eprinomectin is efficacious against A. americanum at lower serum levels in cattle and is eliminated from the serum at a more rapid rate than either doramectin or ivermectin, it provides advantages for use in applications such as the medicated bait for control of ticks on white-tailed deer and could have potential for use in the Cattle Fever Tick Eradication Program.


Assuntos
Doenças dos Bovinos/prevenção & controle , Inseticidas/farmacologia , Ivermectina/análogos & derivados , Infestações por Carrapato/veterinária , Animais , Bovinos , Relação Dose-Resposta a Droga , Ivermectina/farmacologia , Ixodidae/efeitos dos fármacos , Infestações por Carrapato/prevenção & controle , Fatores de Tempo
16.
J Fish Biol ; 75(1): 39-60, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20738481

RESUMO

Observations of multiple years of geographic variation in [Ba:Ca](otolith) and [Mn:Ca](otolith) in black rockfish Sebastes melanops prompted this study to examine the effects of temperature and water concentration on the otolith incorporation of Ba and Mn in this wholly marine species. The replicated experiment design consisted of two water temperatures (7.4 and 13.0 degrees C) and four water concentrations of Ba:Ca and Mn:Ca. A positive, linear relationship between [Ba:Ca](water) and [Ba:Ca](otolith) was observed at both temperatures. A positive temperature effect was also observed with mean partition coefficients for Ba (D(Ba)) greater in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.061 and 0.048, respectively). There was no relationship between [Mn:Ca](water) and [Mn:Ca](otolith) although a negative temperature effect was observed. Mean partition coefficients for Mn (D(Mn)) were lower in the 13 degrees C than in the 7.4 degrees C treatments (mean = 0.027 and 0.036, respectively). The data presented support the assumption of a positive, linear relationship between water and otolith Metal:Ca concentrations for Ba:Ca but not for Mn:Ca. Thus, although indicative of residence in distinct water masses, observed variation in [Metal:Ca](otolith) may not reflect variation in water concentration and can be affected by temperature. Caution should be applied in the interpretation of geographic variation of [Mn:Ca](otolith) until the mechanisms regulating its incorporation are more fully understood.


Assuntos
Bário/metabolismo , Peixes/fisiologia , Manganês/metabolismo , Membrana dos Otólitos/metabolismo , Água do Mar/química , Temperatura , Análise de Variância , Animais , Bário/análise , Tamanho Corporal/fisiologia , Cálcio/análise , Cálcio/metabolismo , Peixes/metabolismo , Manganês/análise , Membrana dos Otólitos/química , Distribuição Aleatória
17.
J Biomech ; 41(9): 1969-77, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18513728

RESUMO

Approximately 90% of hip fractures in older adults result from falls, mostly from landing on or near the hip. A three-dimensional, 11-segment, forward dynamic biomechanical model was developed to investigate whether segment movement strategies prior to impact can affect the impact forces resulting from a lateral fall. Four different pre-impact movement strategies, with and without using the ipsilateral arm to break the fall, were implemented using paired actuators representing the agonist and antagonist muscles acting about each joint. Proportional-derivative feedback controller controlled joint angles and velocities so as to minimize risk of fracture at any of the impact sites. It was hypothesized that (a) the use of active knee, hip and arm joint torques during the pre-contact phase affects neither the whole body kinetic energy at impact nor the peak impact forces on the knee, hip or shoulder and (b) muscle strength and reaction time do not substantially affect peak impact forces. The results demonstrate that, compared with falling laterally as a rigid body, an arrest strategy that combines flexion of the lower extremities, ground contact with the side of the lower leg along with an axial rotation to progressively present the posterolateral aspects of the thigh, pelvis and then torso, can reduce the peak hip impact force by up to 56%. A 30% decline in muscle strength did not markedly affect the effectiveness of that fall strategy. However, a 300-ms delay in implementing the movement strategy inevitably caused hip impact forces consistent with fracture unless the arm was used to break the fall prior to the hip impact.


Assuntos
Acidentes por Quedas , Movimento/fisiologia , Animais , Peso Corporal , Simulação por Computador , Fraturas Ósseas , Articulações/fisiologia , Cinética , Masculino , Fatores de Risco , Estresse Mecânico
18.
J Food Sci ; 73(4): E151-4, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18460123

RESUMO

A commercial long-grain rice flour (CRF) and the flours made by using a pin mill and the Udy mill from the same batch of broken second-head white long-grain rice were evaluated for their particle size and functional properties. The purpose of this study was to compare the commercial rice flour milling method to the pin and Udy milling methods used in our laboratory and pilot plant. The results showed that pin milled flour had more uniform particle size than the other 2 milled flours. The chalky kernels found in broken white milled rice were pulverized more into fines in both Udy milled flour and CRF than in the pin milled flour. The excessive amount of fines in flours affected their functional properties, for example, WSI and their potential usage in the novel foods such as rice breads (RB). The RB made from CRF collapsed more than loaves made from pin milled Cypress long-grain flours.


Assuntos
Farinha , Manipulação de Alimentos/métodos , Oryza , Sementes , Absorção , Pão , Varredura Diferencial de Calorimetria , Tecnologia de Alimentos , Tamanho da Partícula , Solubilidade , Viscosidade , Água
19.
J Vector Ecol ; 33(2): 325-32, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19263853

RESUMO

When white-tailed deer, Odocoileus virginianus, feed on corn bait dispensed by 4-poster tick control devices, they rub against paint rollers impregnated with acaricide. Gray squirrels, Sciurus carolinensis, also feed on the corn bait in the feeding troughs of 4-posters, but in doing so, leave abundant corn fragments and meal that impede the flow of uneaten corn into the troughs. Large accumulations of fragments and meal adversely affect the operation of 4-posters and their use by deer. A battery-operated closure mechanism controlled by a photo sensor was developed to block the flow of corn into the troughs during the day when squirrels are active and deer infrequently visit 4-posters. The effectiveness of the diurnal corn restriction (DCR) concept and restriction mechanism was tested in a field trial at a tick-infested site in Maryland. DCR effectively eliminated accumulation of whole corn, partially eaten corn and corn meal in corn troughs associated with squirrel feeding. At the same time, deer usage of 4-posters was not diminished.


Assuntos
Comportamento Animal , Cervos/parasitologia , Sciuridae , Controle de Ácaros e Carrapatos/instrumentação , Controle de Ácaros e Carrapatos/métodos , Animais , Fatores de Tempo , Zea mays
20.
Am J Physiol Renal Physiol ; 293(5): F1539-44, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17715260

RESUMO

We have demonstrated that oral contraceptive (OC) users exhibit elevated angiotensin II levels and angiotensin II type 1 receptor expression, indicative of renin-angiotensin system (RAS) activation, yet the renal and systemic consequences are minimal, suggesting that there is increased vasodilatory activity, counteracting the effect of RAS activation. We hypothesized that the nitric oxide (NO) system would be upregulated in OC users and that this would be reflected by a blunted hemodynamic response to l-arginine infusion. All subjects were studied after a 7-day controlled sodium and protein diet. Inulin and para-aminohippurate clearance techniques were used to assess renal function. l-Arginine was infused at 100, 250, and 500 mg/kg, each over 30 min. Skin endothelial NO synthase mRNA expression was assessed by real-time PCR. While OC nonusers exhibited significant increases in effective renal plasma flow (670.8 +/- 35.6 to 816.2 +/- 59.7 ml.min(-1).1.73 m(-2)) and glomerular filtration rate (133.4 +/- 4.3 to 151.0 +/- 5.7 ml.min(-1).1.73 m(-2), P = 0.04) and declines in renal vascular resistance (81.1 +/- 6.1 to 63.5 +/- 6.2 mmHg.ml(-1).min, P = 0.001) at the lower l-arginine infusion rates, the responses in OC users were blunted. While l-arginine reduced mean arterial pressure at the 250 and 500 mg/kg doses in OC nonusers, OC users only exhibited a decrease in mean arterial pressure at the highest infusion rate. In contrast, tissue endothelial NO synthase mRNA levels were higher in the OC users (P = 0.04). In summary, these findings suggest that the NO system is upregulated by OC use in young, healthy women. Increased activity of the NO pathway may modulate the hemodynamic effects of RAS activation in OC users.


Assuntos
Anticoncepcionais Orais/farmacologia , Rim/efeitos dos fármacos , Rim/fisiologia , Óxido Nítrico/metabolismo , Regulação para Cima/efeitos dos fármacos , Adulto , Arginina/administração & dosagem , Arginina/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Humanos , Infusões Intravenosas , Inulina/farmacocinética , Óxido Nítrico Sintase Tipo III/genética , RNA Mensageiro/metabolismo , Circulação Renal/efeitos dos fármacos , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologia , Pele/enzimologia , Resistência Vascular/efeitos dos fármacos , Ácido p-Aminoipúrico/farmacocinética
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