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1.
Phys Rev Lett ; 128(13): 132501, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35426696

RESUMO

We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010 GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157 GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15 fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15 fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.

2.
J Biomech ; 114: 110161, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33316540

RESUMO

When recovering balance from a lateral perturbation, younger adults tend to stabilize balance with a single lateral sidestep while older adults often take multistep responses. Using multiple steps to recover balance is consistently associated with increased fall risk, altered body center of mass (CoM) control and instability. The aim of this study was to compare the spatio-temporal stepping characteristics and the margin of stability (MoS) of single lateral sidesteps (LSS1) with the first and second steps of a two-step protective step sequence. Two-step sequences begin with either a cross-over step to the front or back, or a medial step followed by a lateral sidestep. Seventy-one older adults received random lateral waist-pull perturbations to either side. We hypothesized that LSS1 would be more stable (larger MoS) than either step in a two-step sequence. With some exceptions, utilizing a two-step sequence was associated with a reduced CoM velocity and distance between the base of support and CoM and decreased stability in the frontal plane following limb loading of the first and second step. There were no differences in the time available to arrest the extrapolated CoM at the end of a single lateral sidestep or the final step of a two-step sequence. Two-step sequences involving a cross-over step include more complex stepping trajectories and also challeng stability in the sagittal plane requiring a multidimensional balance correction. These results indicate important step type differences in center of mass control in recovering balance with a single lateral sidestep as opposed to a two-step sequence among older adults.


Assuntos
Acidentes por Quedas , Equilíbrio Postural , Abdome , Idoso , Fenômenos Biomecânicos , Humanos
3.
Phys Rev Lett ; 125(11): 112502, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32976004

RESUMO

A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of θ_{lab}=7.9° and a mean energy of 1.149 GeV. The asymmetry result is B_{n}=-5.194±0.067(stat)±0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (θ_{lab}→0) where they should be most reliable.

4.
Naturwissenschaften ; 105(5-6): 36, 2018 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-29754205

RESUMO

Many animals use body coloration as a strategy to communicate with conspecifics, prey, and predators. Color is a trade-off for some species, since they should be visible to conspecifics but cryptic to predators and prey. Some flower-dwelling predators, such as crab spiders, are capable of choosing the color of flowers where they ambush flower visitors and pollinators. In order to avoid being captured, visitors evaluate flowers visually before landing. The crab spider Mecaphesa dubia is a polymorphic species (white/purple color morphs), which inhabits the flower heads of a dune plant, Palafoxia lindenii. Using full-spectrum photography of spiders and flowers, we evaluated how honeybees perceived the spiders at different distances. Using visual modeling, we obtained the chromatic and achromatic contrasts of the spiders on flower heads as perceived by honeybees. Purple morphs were found mainly on the receptacle area and white morphs were equally likely to be found in the flowers and receptacle. According to theoretical modeling, white morphs were visible to honeybees from a distance of 10 cm in receptacle area but appeared to be cryptic in the flower area. Purple morphs were cryptic on the receptacle and less so when they were on the flowers. Spiders on flower heads are predicted to be more easily detected by honeybees using chromatic contrast. Our study shows that the conspicuousness of flower dwelling spiders to honeybees depends on the color morph, the distance of observation, and the position of spider on the flower head.


Assuntos
Abelhas/fisiologia , Percepção de Cores/fisiologia , Modelos Biológicos , Pigmentação , Aranhas/anatomia & histologia , Animais , Comportamento Predatório , Aranhas/fisiologia
5.
BMJ Open ; 6(11): e012356, 2016 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-27810972

RESUMO

INTRODUCTION: Infectious and immune-mediated encephalitides are important but under-recognised causes of morbidity and mortality in childhood, with a 7% death rate and up to 50% morbidity after prolonged follow-up. There is a theoretical basis for ameliorating the immune response with intravenous immunoglobulin (IVIG), which is supported by empirical evidence of a beneficial response following its use in the treatment of viral and autoimmune encephalitis. In immune-mediated encephalitis, IVIG is often used after a delay (by weeks in some cases), while diagnosis is confirmed. Wider use of IVIG in infectious encephalitis and earlier use in immune-mediated encephalitis could improve outcomes for these conditions. We describe the protocol for the first ever randomised control trial of IVIG treatment for children with all-cause encephalitis. METHODS AND ANALYSIS: 308 children (6 months to 16 years) with a diagnosis of acute/subacute encephalitis will be recruited in ∼30 UK hospitals and randomised to receive 2 doses (1 g/kg/dose) of either IVIG or matching placebo, in addition to standard treatment. Recruitment will be over a 42-month period and follow-up of each participant will be for 12 months post randomisation. The primary outcome is 'good recovery' (score of 2 or lower on the Glasgow Outcome Score Extended-paediatric version), at 12 months after randomisation. Additional secondary neurological measures will be collected at 4-6 weeks after discharge from acute care and at 6 and 12 months after randomisation. Safety, radiological, other autoimmune and tertiary outcomes will also be assessed. ETHICS AND DISSEMINATION: This trial has been approved by the UK National Research Ethics committee (South Central-Oxford A; REC 14/SC/1416). Current protocol: V4.0 (10/03/2016). The findings will be presented at national and international meetings and conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBERS: NCT02308982, EudraCT201400299735 and ISRCTN15791925; Pre-results.


Assuntos
Encefalite/tratamento farmacológico , Imunoglobulinas Intravenosas/uso terapêutico , Fatores Imunológicos/uso terapêutico , Adolescente , Criança , Pré-Escolar , Protocolos Clínicos , Encefalite/imunologia , Doença de Hashimoto/tratamento farmacológico , Doença de Hashimoto/imunologia , Humanos , Lactente , Encefalite Infecciosa/tratamento farmacológico , Encefalite Infecciosa/imunologia , Pediatria , Projetos de Pesquisa
6.
Nat Commun ; 7: 12689, 2016 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-27573539

RESUMO

Photon upconversion has the potential to increase the efficiency of single bandgap solar cells beyond the Shockley Queisser limit. Efficient light management is an important point in this context. Here we demonstrate that the direction of upconverted emission can be controlled in a reversible way, by embedding anthracene derivatives together with palladium porphyrin in a liquid crystalline matrix. The system is employed in a triplet-triplet annihilation photon upconversion scheme demonstrating controlled switching of directional anti Stokes emission. Using this approach an emission ratio of 0.37 between the axial and longitudinal emission directions and a directivity of 1.52 is achieved, reasonably close to the theoretical maximal value of 2 obtained from a perfectly oriented sample. The system can be switched for multiple cycles without any visible degradation and the speed of switching is only limited by the intrinsic rate of alignment of the liquid crystalline matrix.

7.
J Electromyogr Kinesiol ; 25(6): 959-65, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26475243

RESUMO

This study compared self-induced stepping reactions of seventeen participants after stroke and seventeen controls. Surface electromyographic (EMG) signals were recorded bilaterally from the soleus (SOL), tibialis anterior (TA), biceps femoris (BF) and rectus femoris (RF) muscles. Principal component analysis (PCA) was used to reduce the data into muscle activation patterns and examine group differences (paretic, non-paretic, control leg). The first principal component (PC1) explained 46.7% of the EMG signal of the stepping leg. Two PCs revealed distinct activation features for the stepping paretic leg: earlier TA onset at step initiation and earlier BF and SOL onset at mid-step. For the stance leg, PC1 explained 44.4% of the EMG signal and significant differences were found in the non-paretic leg compared to paretic (p < 0.001) and control (p < 0.001). In PC1, at step onset the BF and SOL EMG and the RF and TA EMG were increased over the latter half of the step. No PC loadings were distinct for the paretic leg during stance, however differences were found in the non-paretic leg: earlier TA burst and increased BF and SOL EMG at step initiation. The results suggest impairments in the paretic leg when stepping and compensatory strategies in the non-paretic stance leg.


Assuntos
Músculo Esquelético/fisiologia , Paresia/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Caminhada , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Paresia/etiologia , Acidente Vascular Cerebral/complicações
8.
Radiol Manage ; 37(4): 16-9; quiz 20-1, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26480592

RESUMO

Organizations need to be ready for the imaging workflow changes related to the legislative mandates of P.L. 113-93 (Protecting Access to Medicare Act of 2014). They also need to have a good understanding of what's required to meet these mandates. There has been only one large scale study to determine the possible value of imaging CDS. Beginning in 2009, CMS initiated the Medicare Imaging Demonstration (MID) project--its subsequent evaluation is very instructive. The use of imaging CDS will be required for submitting claims to CMS as of January 1, 2017. This means a mechanism that the Secretary of HHS has approved must be used and the results from that imaging CDS must be included on the claim submitted by the imaging facility.


Assuntos
Sistemas de Apoio a Decisões Clínicas , Diagnóstico por Imagem , Educação Continuada , Medicare/legislação & jurisprudência , Estados Unidos
9.
Bioresour Technol ; 156: 408-11, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24534441

RESUMO

The effect of varying levels of phosphorus (P) on Isochrysis galbana U4 growth, pigmentation and lipid accumulation were investigated. A reduction in the P content to 25% of the recommended level for f/2 medium did not lead to declines in cell growth rates or lipid accumulation levels relative to the cultures maintained on medium supplemented with the normal P dose. Evidence suggesting that the recommended P supply in f/2 exceeds the requirements for maximal algal growth has obvious economic implications for the mass production of I. galbana for biodiesel production. When P supply was in excess this species was also found to accumulate intracellular levels of P that exceeded by up to 6 times its P requirements for growth and cell division. The reduction in P concentration to levels below 25% resulted in P starvation stimulated chlorophyll reductions and carotenoid and lipid accumulation in this species.


Assuntos
Biocombustíveis , Haptófitas/crescimento & desenvolvimento , Haptófitas/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Fósforo/deficiência , Haptófitas/efeitos dos fármacos , Nitratos/metabolismo , Fósforo/farmacologia , Pigmentação/efeitos dos fármacos
10.
Chem Commun (Camb) ; 50(20): 2575-8, 2014 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-24441417

RESUMO

Biaryl coupling (often labelled 'C-H activation') of aromatic systems can be achieved by potassium tert-butoxide alone in the absence of any amine or bipyridine catalyst (1,10-phenanthroline or N,N'-dimethylethylenediamine being the most common), previously reported to be essential. Various mechanistic studies and observations are presented which suggest that when 1,10-phenanthroline is employed as the catalyst, the alkoxide is destroyed almost immediately.


Assuntos
Butanóis/química , Diaminas/química , Fenantrolinas/química , Catálise , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Elementos de Transição/química
11.
Phys Rev Lett ; 111(14): 141803, 2013 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-24152148

RESUMO

The Q(weak) experiment has measured the parity-violating asymmetry in ep elastic scattering at Q(2)=0.025(GeV/c)(2), employing 145 µA of 89% longitudinally polarized electrons on a 34.4 cm long liquid hydrogen target at Jefferson Lab. The results of the experiment's commissioning run, constituting approximately 4% of the data collected in the experiment, are reported here. From these initial results, the measured asymmetry is A(ep)=-279±35 (stat) ± 31 (syst) ppb, which is the smallest and most precise asymmetry ever measured in ep scattering. The small Q(2) of this experiment has made possible the first determination of the weak charge of the proton Q(W)(p) by incorporating earlier parity-violating electron scattering (PVES) data at higher Q(2) to constrain hadronic corrections. The value of Q(W)(p) obtained in this way is Q(W)(p)(PVES)=0.064±0.012, which is in good agreement with the standard model prediction of Q(W)(p)(SM)=0.0710±0.0007. When this result is further combined with the Cs atomic parity violation (APV) measurement, significant constraints on the weak charges of the up and down quarks can also be extracted. That PVES+APV analysis reveals the neutron's weak charge to be Q(W)(n)(PVES+APV)=-0.975±0.010.

12.
Bioresour Technol ; 102(19): 8986-91, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21782420

RESUMO

Biohydrogen production in an anaerobic fluidized granular bed bioreactor was strongly dependent on temperature and effluent recycle rates. At 45 °C as the effluent recycle rate was increased from 1.3 to 3.5 L/min, the total H2 output for the bioreactor increased from 10.6 to 43.2 L/h. Volumetric H(2) productivity also increased from 2.1 to 8.7 L H2/L/h. At 70°C as the effluent recycle was increased from 1.3 to 3.5 L/min, the total H2 output for the bioreactor increased from 13.8 to 73.8L/h. At 70 °C volumetric H(2) productivities increased from 2.8 to 14.8L H2/L/h as the effluent recycle rate was increased from 1.3 to 3.5 L/min. At 45 °C % H2 was 45% and reached 67% at 70 °C. Maximum hydrogen yields at 45 °C were 1.24 and 2.2 mol H2/mol glucose at 70 °C.


Assuntos
Bactérias Anaeróbias/metabolismo , Biocombustíveis , Reatores Biológicos , Biotecnologia/métodos , Hidrogênio/metabolismo , Temperatura
13.
Intern Med J ; 40(3): 209-13, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19220537

RESUMO

BACKGROUND: There is limited information on the causes of neurological disorders in an Australian rural setting. METHODS: This study reports on a prospective cohort of 160 patients (95 women and 65 men) with a mean age of 55.1 years (standard deviation 19.78 years, range 12-92 years) receiving a neurological work-up from one neurologist attending the Geraldton and Midwest region of Western Australia over a 12-month period. RESULTS: Patients were divided into 15 diagnostic classifications. Movement disorders were the most common diagnostic classification (38 of 160 or 23.75%) and Parkinson's disease was the most common movement disorder (30 of 38 or 78.95%) with an estimated period of prevalence of 187.5 persons per 1000. Of the other neurological disorder diagnosis classifications the following number of patients per group was observed: epilepsy (27 or 16.87%); neuromuscular disorders (22 or 13.75%); multiple sclerosis (12 or 7.5%); cerebrovascular disease (10 or 6.25%); headaches (7 or 4.37%); neurodegenerative (7 or 4.37%); dementias (6 or 3.75%); memory dysfunction (6 or 3.75%); gait disorders (4 or 2.5%); vestibular syndrome (3 or 1.87%); pain syndrome (3 or 1.87%); sensory syndrome (2 or 1.25%); brain injury (1 or 0.62%) and miscellaneous (12 or 7.5%). A high number of persons having Parkinson's disease was found. CONCLUSION: Possible risk factors for Parkinson's disease for individuals living in Geraldton and Midwest region need to be investigated. This study raises issues pertaining to the provision of services and allocation of resources in rural areas, especially for patients with Parkinson's disease.


Assuntos
Doenças do Sistema Nervoso/diagnóstico , Doenças do Sistema Nervoso/epidemiologia , População Rural , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/diagnóstico , Doença de Parkinson/epidemiologia , Estudos Prospectivos , Austrália Ocidental/epidemiologia , Adulto Jovem
14.
J Appl Microbiol ; 104(2): 554-65, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18194259

RESUMO

AIMS: In view of the major problems encountered by microbiologists in obtaining reproducible data on growth dynamics in complex media, we studied the effects of different peptones made from different biological sources and produced by numerous manufacturers. METHODS AND RESULTS: Peptones (including casein, gelatin, meat, soy and yeast) were assessed as a constituent of the pre-enrichment broth buffered peptone water (BPW). Generation times (g) and yields of Salmonella serovar Typhimurium were significantly affected by the type of peptone employed with yeast peptones generating yields of 7.04 x 10(9) CFU ml(-1) and gelatin peptones producing 0.81 x 10(9) CFU ml(-1). Medium sterilization was also found to have significant effects (P = 0.000) upon subsequent bacterial growth. Filter sterilization of BPW media produced lower generation times compared with those obtained after sterilization by autoclaving. Finally, it was observed that some peptones which produced good growth when inoculated with healthy organisms, showed relatively poor growth when inocula were sublethally injured by heating. CONCLUSIONS: Variation in peptone as a constituent of BPW has a significant effect on growth and enumeration of bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: Increased consideration with respect to culture media may significantly improve bacterial growth and experimental reproducibility.


Assuntos
Microbiologia de Alimentos , Peptonas/farmacologia , Salmonella typhimurium/crescimento & desenvolvimento , Técnicas Bacteriológicas , Soluções Tampão , Contagem de Colônia Microbiana , Meios de Cultura , Gelatina/farmacologia , Temperatura Alta , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/metabolismo , Esterilização , Leveduras/metabolismo
15.
Bioresour Technol ; 99(11): 5115-9, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17933525

RESUMO

Gram-negative bacteria with the potential to metabolize n-alkanes and cyclic hydrocarbons were isolated from local soils and identified using 16S rDNA sequence analysis. Three isolates (CS1CO, GL1CO, GCI1CO) were identified as strains of Pseudomonas (P.) aeruginosa and a further strain (DSS2) as P. putida. Isolates were co-cultured in a laboratory-scale fluidized bed biofilm bioreactor (FBBR) utilizing sodium benzoate as the sole carbon source, under two batch and/or one continuous growth conditions. Biofilm and planktonic bacterial growth dynamics were monitored by plate counts, and optical density measurements (230 nm) determined benzoate biodegradation. Overall higher attached and planktonic bacterial counts, and benzoate depletion, were determined under batch compared to continuous conditions, and the bioreactor performed better during the second batch phase when compared to the first batch phase. It thus appeared that both the planktonic and biofilm components of the system were necessary for the most successful sodium benzoate degradation in this system.


Assuntos
Reatores Biológicos , Bactérias Gram-Negativas/metabolismo , Benzoato de Sódio/metabolismo , Biodegradação Ambiental , Biofilmes , Contagem de Colônia Microbiana , DNA Ribossômico/genética , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Negativas/fisiologia , Filogenia , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/isolamento & purificação , Pseudomonas/metabolismo , Pseudomonas/fisiologia
16.
J Appl Microbiol ; 101(5): 1105-13, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17040234

RESUMO

AIMS: To test the effects of C : N : P ratio modification of a well-known nutrient medium formulation, the Endo formulation on biofilm formation by Enterobacter cloacae Ecl and Citrobacter freundii Cf1 in both single-species and binary species biofilms. METHODS AND RESULTS: The C : N : P atom : atom ratio of a well-known nutrient medium formulation, the Endo formulation, that has been applied in fermentative biohydrogen studies, was modified to include two different C concentrations, one containing 17.65 g l(-1) and the other 8.84 g l(-1) sucrose, each containing four different C : N : P ratios, two at higher C : N : P ratios (334 : 84 : 16.8 and 334 : 84 : 3) and two at lower C : N : P ratios (334 : 28 : 5.6 and 334 : 28 : 1). Attached cells were enumerated after dislodging the biofilms that had formed on granular activated carbon (GAC). The modified medium containing 17.65 g l(-1) sucrose and having a C : N : P ratio of 334 : 28 : 5.6 resulted in significantly (P < 0.05) higher counts of attached cells for both single-species biofilms at 7.73 log(10) CFU g(-1) GAC and 9.3 log(10)CFU g(-1) GAC for Ent. cloacae Ecl and Cit. freundii Cf1, respectively, and binary species biofilms at 8.2 log(10) CFU g(-1) GAC and 6.34 log(10) CFU g(-1) GAC for Ent. cloacae Ecl and Cit. freundii Cf1, respectively. Scanning electron micrographs showed qualitative evidence that the 334 : 28 : 5.6 ratio encouraged more complex and extensive biofilm growth for both single-species and binary species biofilms. CONCLUSIONS: The differences in the attachment numbers between the different ratios were found not to be a result of the individual actions of the bacterial isolates involved but rather because of the effects of the various C : N : P ratios. The 334 : 28 : 5.6 ratio showed significantly (P < 0.05) higher counts of attached cells for both single-species and binary species biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study indicates that C : N : P ratios should be a key consideration with regard to maximizing biofilm formation in shake flask and fluidized bed bioreactor studies as well as understanding fundamental factors affecting biofilm growth in natural environments.


Assuntos
Biofilmes/efeitos dos fármacos , Citrobacter freundii/fisiologia , Meios de Cultura/química , Enterobacter cloacae/fisiologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Reatores Biológicos , Carbono/farmacologia , Citrobacter freundii/efeitos dos fármacos , Citrobacter freundii/crescimento & desenvolvimento , Citrobacter freundii/ultraestrutura , Meios de Cultura/farmacologia , Relação Dose-Resposta a Droga , Enterobacter cloacae/efeitos dos fármacos , Enterobacter cloacae/crescimento & desenvolvimento , Enterobacter cloacae/ultraestrutura , Microscopia Eletrônica de Varredura , Nitrogênio/farmacologia , Fósforo/farmacologia , Sacarose/farmacologia
17.
J Food Prot ; 69(2): 282-7, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16496566

RESUMO

We developed a rapid and reliable PCR assay with genus-specific primers for the detection of Salmonella in food samples. With these primers, no primer-specific amplicons were detected when challenged with cultures of microorganisms other than salmonellae, and positive results, i.e., Salmonella-specific bands, were obtained with pure cultures of all 125 Salmonella isolates tested, which represented 100 serovars. The PCR assay was optimized using both pure cultures and artificially inoculated food samples. The assay results were compared with those of the Australian standard culture methods, using more than 500 "naturally" contaminated food samples, over a period of 9 years. Food samples were subjected to nonselective preenrichment in buffered peptone water followed by selective enrichment in Rappaport Vassiliadis (RV) broth and mannitol selenite cystine (MSC) broth. A simple sample preparation method was developed based on concentrating bacterial cells from 1 ml of RV or MSC broths. The PCR results were in perfect agreement with the results of the standard culture methods; no false-positive or false-negative results were obtained. However, the PCR assay was extremely rapid, and results could be obtained within 4 h of testing of enrichment broths.


Assuntos
Contaminação de Alimentos/análise , Microbiologia de Alimentos , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/normas , Salmonella/isolamento & purificação , Austrália , Contagem de Colônia Microbiana/métodos , Qualidade de Produtos para o Consumidor , Primers do DNA , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Especificidade da Espécie , Fatores de Tempo
19.
Ann Bot ; 89(5): 645-8, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12099540

RESUMO

Culture of cassava somatic embryos on media with an altered macro- and micro-nutrient salt concentration affected embryo development and germination capability. In the tests, quarter-, half-, full- or double-strength Murashige and Skoog (MS) media were compared. The maximum number of somatic embryos differentiated from a proliferative nodular embryogenic callus (NEC) on either half- or full-strength MS medium, and the greatest numbers of cotyledonary stage embryos were formed on full-strength MS medium. Developed somatic embryos were then desiccated above a saturated K2SO4 solution for 10 d. After transfer to germination medium, embryos that had developed on half- and full-strength MS medium yielded 8.3 and 8.6 germinants g(-1) NEC tissue, respectively. For this important but often disregarded culture factor, either half- or full-strength MS medium is recommended for both the differentiation and development of cassava somatic embryos that are capable of germination.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Cotilédone/efeitos dos fármacos , Manihot/efeitos dos fármacos , Sais/farmacologia , Sementes/efeitos dos fármacos , Cotilédone/crescimento & desenvolvimento , Meios de Cultura/farmacologia , Técnicas de Cultura/métodos , Dessecação/métodos , Relação Dose-Resposta a Droga , Germinação/efeitos dos fármacos , Manihot/citologia , Manihot/embriologia , Sementes/crescimento & desenvolvimento , Água/fisiologia
20.
Oncogene ; 20(43): 6250-7, 2001 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-11593435

RESUMO

Mutation of the adenomatous polyposis coli (APC) gene and the subsequent dysregulation of beta-catenin are well-documented abnormalities in familial adenomatous polyposis (FAP), as well as sporadic polyposis. Intriguingly, overexpression of the integrin-linked kinase (ILK) has been shown to modulate beta-catenin subcellular localization and function. However, the significance of this finding for human carcinogenesis remains unclear. Here, we report the increased biochemical activity and expression of ILK protein in polyps from FAP patients. Furthermore, dramatic increases in ILK immunoreactivity were observed in all abnormal crypts from sporadic polyps, when compared with the normal appearing crypts within the same resected specimens. As sulindac and aspirin are the two most important therapeutic/chemopreventative agents demonstrated in colorectal carcinogenesis, in both humans and animals, further investigation revealed that these non-steroidal anti-inflammatory drugs (NSAIDs) target ILK and ILK-mediated events in vivo. These include inhibition of, both the biochemical activation of ILK, inhibition of serine 9 GSK3beta phosphorylation and the enhancement of TCF-4 transcriptional activity. In conclusion, ILK protein hyperexpression appears to be an early event in colonic polyposis. Additionally, ILK signaling is shown to undergo modulation by sulindac (and aspirin) for the first time, indicating that it is likely to be one of the targets affected by these agents in vivo.


Assuntos
Polipose Adenomatosa do Colo/enzimologia , Polipose Adenomatosa do Colo/genética , Regulação Enzimológica da Expressão Gênica , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Anti-Inflamatórios não Esteroides/farmacologia , Aspirina/farmacologia , Pólipos do Colo/metabolismo , Pólipos do Colo/patologia , Progressão da Doença , Relação Dose-Resposta a Droga , Regulação para Baixo , Humanos , Mutação , Fosforilação , Serina/metabolismo , Sulindaco/farmacologia , Fatores de Tempo , Células Tumorais Cultivadas
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