bluuebunny/crossref_metadata_2025 huggingface dataset:
Arpin deficiency increases actomyosin contractility and vascular permeability
Authors: Montoya-García Armando , Guerrero-Fonseca Idaira M. , Chánez-Paredes Sandra D. , Hernández-Almaraz Karina B. , León-Vega Iliana I. , Silva-Olivares Angélica , Bentazos Abigail , Mondragón-Castelán Mónica , Mondragón-Flores Ricardo , Salinas-Lara Citlaltepetl , Vargas-Robles Hilda , Schnoor Michael
Published: September 2023

Arpin was discovered as an inhibitor of the Arp2/3 complex localized at the lamellipodial tip of fibroblasts, where it regulated migration steering. Recently, we showed that arpin stabilizes the epithelial barrier in an Arp2/3-dependent manner. However, expression and functions of arpin in endothelial cells (EC) have not yet been described. Arpin mRNA and protein are expressed in EC and downregulated by pro-inflammatory cytokines. Arpin depletion in HUVEC causes the formation of actomyosin stress fibers leading to increased permeability in an Arp2/3-independent manner. Instead, inhibitors of ROCK1 and ZIPK, kinases involved in the generation of stress fibers, normalize the loss-of-arpin effects on actin filaments and permeability. Arpin-deficient mice are viable but show a characteristic vascular phenotype in the lung including edema, microhemorrhage and vascular congestion, increased F-actin levels and vascular permeability. Our data show that, apart from being an Arp2/3 inhibitor, arpin is also a regulator of actomyosin contractility and endothelial barrier integrity.The expression and functions of arpin in endothelial cells are unknown. We show that arpin controls actomyosin contractility and endothelial barrier integrity in an Arp2/3-independent manner via ROCK1/ZIPK. Arpin-deficient mice are viable, but also show increased basal and induced vascular permeability. Under basal conditions arpin is located throughout the cell and enriched at cellular junctions. During inflammation, arpin is downregulated causing the formation of actomyosin actin stress fibers, junction disruption, and increased permeability. Question mark indicates the hitherto unknown mechanism of how arpin controls the activity of ROCK and ZIPK to induce the formation of contractile actin stress fibers.
Structure and dynamics of cholesterol-mediated aquaporin-0 arrays and implications for lipid rafts
Authors: Chiu Po-Lin , Orjuela Juan D. , de Groot Bert L. , Aponte-Santamaría Camilo , Walz Thomas
Published: September 2023

Aquaporin-0 (AQP0) tetramers form square arrays in lens membranes through a yet unknown mechanism, but lens membranes are enriched in sphingomyelin and cholesterol. Here, we determined electron crystallographic structures of AQP0 in sphingomyelin/ cholesterol membranes and performed molecular dynamics (MD) simulations to establish that the observed cholesterol positions represent those seen around an isolated AQP0 tetramer and that the AQP0 tetramer largely defines the location and orientation of most of its associated cholesterol molecules. At a high concentration, cholesterol increases the hydrophobic thickness of the annular lipid shell around AQP0 tetramers, which may thus cluster to mitigate the resulting hydrophobic mismatch. Moreover, neighboring AQP0 tetramers sandwich a cholesterol deep in the center of the membrane. MD simulations show that the association of two AQP0 tetramers is necessary to maintain the deep cholesterol in its position and that the deep cholesterol increases the force required to laterally detach two AQP0 tetramers, not only due to protein–protein contacts but also due to increased lipid–protein complementarity. Since each tetramer interacts with four such ‘glue’ cholesterols, avidity effects may stabilize larger arrays. The principles proposed to drive AQP0 array formation could also underlie protein clustering in lipid rafts.
Conformation Selection by ATP-competitive Inhibitors and Allosteric Communication in ERK2
Authors: Anderson Jake W. , Vaisar David , Jones David N. , Pegram Laurel M. , Chen Huifen , Moffat John G. , Ahn Natalie G.
Published: September 2023

Activation of the extracellular signal regulated kinase-2 (ERK2) by phosphorylation has been shown to involve changes in protein dynamics, as determined by hydrogen-deuterium exchange mass spectrometry (HDX-MS) and NMR relaxation dispersion measurements. These can be described by a global exchange between two conformational states, named “L” and “R”, where R is associated with a catalytically productive ATP-binding mode. An ATP-competitive ERK1/2 inhibitor, Vertex-11e, has properties of conformation selection for the R-state, revealing movements of the activation loop that are allosterically coupled to the kinase active site. However, the features of inhibitors important for R-state selection are unknown. Here we survey a panel of ATP-competitive ERK inhibitors using HDX-MS and NMR and identify 14 new molecules with properties of R-state selection. They reveal effects propagated to distal regions in the P+1 and helix αF segments surrounding the activation loop, as well as helix αL16. Crystal structures of inhibitor complexes with ERK2 reveal systematic shifts in the Gly loop and helix αC, mediated by a Tyr-Tyr ring stacking interaction and the conserved Lys-Glu salt bridge. The findings suggest a model for the R-state involving small movements in the N-lobe that promote compactness within the kinase active site and alter mobility surrounding the activation loop. Such properties of conformation selection might be exploited to modulate the protein docking interface used by ERK substrates and effectors.
Fluorofenidone alleviates liver fibrosis by inhibiting hepatic stellate cell autophagy via the TGF-β1/Smad pathway: implications for liver cancer
Authors: Peng Xiongqun , Yang Huixiang , Tao Lijian , Xiao Jingni , Zeng Ya , Shen Yueming , Yu Xueke , Zhu Fei , Qin Jiao
Published: September 2023

Objectives

Liver fibrosis is a key stage in the progression of various chronic liver diseases to cirrhosis and liver cancer, but at present, there is no effective treatment. This study investigated the therapeutic effect of the new antifibrotic drug fluorofenidone (AKF-PD) on liver fibrosis and its related mechanism, providing implications for liver cancer.

Materials and Methods

The effects of AKF-PD on hepatic stellate cell (HSC) autophagy and extracellular matrix (ECM) expression were assessed in a carbon tetrachloride (CCl4)-induced rat liver fibrosis model. In vitro, HSC-T6 cells were transfected with Smad2 and Smad3 overexpression plasmids and treated with AKF-PD. The viability and number of autophagosomes in HSC-T6 cells were examined. The protein expression levels of Beclin-1, LC3 and P62 were examined by Western blotting. The Cancer Genome Atlas (TCGA) database was used for comprehensively analyzing the prognostic values of SMAD2 and SMAD3 in liver cancer. The correlation between SMAD2, SMAD3, and autophagy-related scores in liver cancer was explored. The drug prediction of autophagy-related scores in liver cancer was explored.

Results

AKF-PD attenuated liver injury and ECM deposition in the CCl4-induced liver fibrosis model. In vitro, the viability and number of autophagosomes in HSCs were reduced significantly by AKF-PD treatment. Meanwhile, the protein expression of FN, α-SMA, collagen III, Beclin-1 and LC3 was increased, and P62 was reduced by the overexpression of Smad2 and Smad3; however, AKF-PD reversed these effects. SMAD2 and SMAD3 were hazardous factors in liver cancer. SMAD2 and SMAD3 correlated with autophagy-related scores in liver cancer. Autophagy-related scores could predict drug response in liver cancer.

Conclusions

AKF-PD alleviates liver fibrosis by inhibiting HSC autophagy via the transforming growth factor (TGF)-β1/Smadpathway. Our study provided some implications about how liver fibrosis was connected with liver cancer by SMAD2/SMAD3 and autophagy.
Systematic bioprospection for cellulolytic actinomycetes in the Chihuahuan Desert: isolation and enzymatic profiling
Authors: Escudero-Agudelo Janneth , Martínez-Villalobos Juan , Arocha-Garza Hector , Galán-Wong Luis Jesús , Avilés-Arnaut Hamlet , De la Torre-Zavala Susana
Published: September 2023

The quest for microbial cellulases has intensified as a response to global challenges in biofuel production. The efficient deconstruction of lignocellulosic biomass holds promise for generating valuable products in various industries such as food, textile, and detergents. This article presents a systematic bioprospection aimed at isolating actinomycetes with exceptional cellulose deconstruction capabilities. Our methodology explored the biodiverse oligotrophic region of Cuatro Cienegas, Coahuila, within the Chihuahuan Desert. Among the evaluated actinomycetes collection, 78% exhibited cellulolytic activity. Through a meticulous screening process based on enzymatic index evaluation, we identified a highly cellulolytic Streptomyces strain for further investigation. Submerged fermentation of this strain revealed an endoglucanase enzymatic activity of 149 U/mg. Genomic analysis of strain Streptomyces sp. STCH565-A revealed unique configurations of carbohydrate-active enzyme (CAZyme) genes, underscoring its potential for lignocellulosic bioconversion applications. These findings not only highlight the significance of the Chihuahuan Desert as a rich source of cellulolytic microorganisms but also offer insights into the systematic exploration and selection of high-performing cellulolytic microorganisms for application in diverse environmental contexts. In conclusion, our bioprospecting study lays a foundation for harnessing the cellulolytic potential of actinomycetes from the Chihuahuan Desert, with implications for advancing cellulose deconstruction processes in various industries. The findings can serve as a blueprint for future bioprospecting efforts in different regions, facilitating the targeted discovery of microorganisms with exceptional cellulosic deconstruction capabilities.
Code Switching and Code Mixing on Social Media Writing Skills among University Undergraduates in Ekiti State, Nigeria
Authors: Miriam Olajobi Oluatomisin , Ofodu G. O.
Published: September 2023

The study investigated code switching and code mixing on social media writing skills of the University undergraduates in Ekiti State, Nigeria. The study investigated the level of code switching and code mixing among male and female undergraduates on social media writing and it also examines the influence of code switching and code mixing on social media writing skills among universities undergraduates in Ekiti State. The descriptive survey research design was adopted in the study. Multistage sampling procedure was used to select the sample. The first stage purposive sampling techniques were used to sample all the four university in Ekiti state. The second stage, proportional sampling technique was used to sample from of the four universities. The third stage simple random sampling techniques was used to sample undergraduates from each faculty in four universities. Questionnaire was used to collect data on the study. Section A focused on the demographic variables of the respondents such as name of university, faculty and level of study and undergraduate background. Section B was made up items to elicit information on code mixing and code switching undergraduates on social media writing skills. The reliability of the instrument was determined through test, re-test method and in doing this, the instrument administered on 20 respondents outside the sample twice within the interval of two weeks. The two responses were correlated and analysed using test re-test, which yielded a reliability coefficient of 0.73. The data collected was analysed using descriptive and inferential statistics. The descriptive statistics such as the frequency counts percentages and bar chart were used to answer research questions. Hypotheses 1 and 2 were tested using Pearson’s Product moment correlation; hypotheses 3, 4 were tested using t-test. All the hypotheses were tested at 0.05 level of significance. Therefore, the University undergraduates should stick to the option of language they choose to use on social media and that code switching and code mixing should be used alongside with quotation marks to indicate deliberate use of other codes on social media to show compliance with syntactic rules guiding writing.
Behavioural Pattern of Solar Filter Enhanced Photovoltaics in Mangrove Swamp
Authors: Njok Armstrong. O. , Ogbulezie Julie. C. , Eyire Osang. J.
Published: September 2023

Not all wavelengths incident on a solar cell enhances the efficiency of the cell. Some wavelengths only cause electrons to twist and vibrate in their bonds which heats up the cell and inevitably hinder its efficiency. To tackle this problem, solar cells need to be exposed to distinct wavelengths of light so as to ascertain those wavelengths that adversely affect its efficiency. This study is aimed at experimentally investigating the effect of solar power and solar flux on photovoltaic (PV) modules enhanced with solar filters. The objective includes to ascertain which filter triggered higher power and efficiency from PV modules. In achieving the objectives, color filters were employed for wavelength selection, an intelligent photovoltaic maximum power point tracker was employed to determine the maximum voltage, current and efficiency of the PV module at a particular level of solar power and solar flux, while solar power and solar flux meters were employed to track the amount of the transmitted solar power and solar flux reaching the surface of the PV module. The experimental measurements were conducted in outdoor real-time conditions with varying levels of solar power and solar flux. The results revealed points of voltage increase and points of voltage stability, and also revealed filters that attained voltage stability with relatively lower levels of solar power (400 W/m2 for orange and blue filter) and solar flux (45 Klx for lemon filter). The results also reveal the module attaining a higher efficiency under the red filter as solar flux increases. In terms of solar power, the red filter and the natural spectrum led in power generation, but the natural spectrum triggered a higher efficiency from the module as solar power increases. This study proved that the nature and wavelength of the radiation reaching a photovoltaic module influences its behavior and efficiency.
Effect of Integrated Nutrient Management on Growth, Yield, Nutrient Uptake and Economics of Rabi Sorghum (Sorghum bicolor (L.) Moench)
Authors: Tudu Akash Kumar , Palai Jnana Bharati , Shankar Tanmoy , Adhikary Rahul , Mondal Triptesh , Nath Suprava
Published: September 2023

Long term study on different crops indicated that application of balanced NPK fertilizer couldn’t meet higher yield due to poor physical properties and micronutrient deficiencies. Keeping in view to the above concept a experiment entitled “Effect of Integrated Nutrient Management on Growth and Yield of Rabi Sorghum (Sorghum bicolor (L.) Moench)” was conducted at post graduate experimental farm of M.S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Paralakhemundi during the rabi season, 2022. The experimental soil was sandy loam with low in available nitrogen and medium in phosphorus and potassium. The experimental design was randomized block design, which consists of 10 numbers of treatments as different combinations of recommended dose of fertilizer (RDF) and farmyard manure (FYM), each treatment replicated thrice. The treatments are T­1: Control, T2: 50% RDF, T3: 75%RDF, T4: 100%RDF, T5: 50%RDF+5t FYM ha-1, T6: 50% RDF + 10t FYM ha-1, T7: 75% RDF + 5t FYM ha-1, T8: 75%RDF+10t FYM ha-1, T9: 100%RDF + 5t FYM ha-1, T10: 100%RDF + 10t FYM ha-1. Among all the treatments significantly highest growth, yield attributes and nutrient uptake were recorded from the treatment 100% RDF + 10t FYM ha-1(T10). Application of 100% RDF + 10t FYM ha-1 recorded highest sorghum grain yield (2416 kg ha-1) and gross return (₹85108/- ha-1). However, maximum net return (₹48010/- ha-1) was recorded from 100%RDF + 5t FYM ha-1 but B:C ratio (1.49) from 75%RDF.
In-vitro Screening of EMS and Sodium Azide Induced Mutant Population at Seedling Stage for Drought Tolerance in Wheat (Triticum aestivum L.)
Authors: Rani Ritu , Yadav Manoj Kumar , Tomar Akash , Vaishali  , Gangwar Lokesh Kumar , Sengar Rakesh Singh
Published: September 2023

Drought caused by climate change result in water shortages, decreased global wheat production and unevenly distributed heavy rains. About 50% of the global wheat production is affected by water deficit conditions. The effects of different concentrations of EMS and SA on HD-3226 and HI-1620 wheat genotype for drought tolerance capability were investigated at seedling stage under water and osmotic stress conditions. In the present study, 15% concentration of polyethylene glycol (PEG-6000, to mimic drought stress) was used for in-vitro screening of EMS and SA induced mutant lines of both wheat genotypes. Current study revealed that SA decreased germination of seeds, seedling length, seed vigour index and survival rate percentage while it increased morphological mutation frequency percentage as comparison to EMS treatment in both wheat genotypes under water and PEG stress. Moreover, osmotic stress significantly reduced seed germination, shoot length, root length, seed vigour index, survival rate percentage compared to control-wild type.
O PACIENTE FORA DE POSSIBILIDADE TERAPÊUTICA CURATIVA E A RECUSA DE TRATAMENTOS MÉDICOS
Authors: Fêrnandes Hélder
Published: September 2023

RESUMO: A partir de uma interpretação conforme à constituição este artigo elencou as orientações do Conselho Federal de Medicina e as disposições do Código Civil Brasileiro correlatas à recusa de tratamentos médicos. Discutiu se o anteparo do risco iminente de morte dificulta ao paciente que enfrenta a terminalidade a tomada de decisão sobre os rumos da sua saúde e propôs a observação de outros limites. Com abordagem qualitativa, de objetivo descritivo-explicativo e finalidade básica estratégica, foi através dos métodos hermenêutico e dedutivo que construiu os seus argumentos, para tanto o procedimento adotado partiu da análise bibliográfica e documental.

 

Palavras-chaves: autodeterminação; risco iminente de morte; terminalidade.
PERSPECTIVAS SOBRE RESPONSABILIDADE CIVIL DOS HOSPITAIS NA VIOLAÇÃO DO DIREITO AO ABORTO LEGAL
Authors: Soares Marcondes Tais
Published: September 2023

O presente trabalho apresenta perspectivas sobre o aborto no Brasil, abordando a problemática de forma a considerar a apuração de responsabilidade civil da instituição hospitalar na violação ao direito ao aborto legal em ampla acepção, perpassando pelas hipóteses aplicáveis e propondo alternativas que visam dirimir a prática de lesão ao direito ao aborto legal. O presente trabalho fora elaborado com base na metodologia de pesquisa bibliográfica e doutrinária, de natureza qualitativa, com utilização de método hipotético-dedutivo, contextualizando com os parâmetros legais estabelecidos na proposta de uma abordagem sobre o tema.
LIMITES BIOJURÍDICOS DAS CONDUTAS NEOEUGÊNICAS NO ÂMBITO DA REPRODUÇÃO HUMANA ASSISTIDA
Authors: Verdival Rafael
Published: September 2023

O presente trabalho tem como objetivo analisar quais são os limites bioéticos e jurídicos de escolhas seletivas realizadas no contexto da reprodução humana assistida. Para tanto, inicialmente, analisa o exercício dos direitos reprodutivos no contexto dos avanços biotecnológicos que ampliam as possibilidades de reprodução através técnicas medicamente assistidas. Em seguida, elucida o conceito de neoeugenia, compreendida como condutas seletivas praticadas no contexto dos avanços biotecnológicos, em especial na esfera reprodutiva. Por meio dessa compreensão, demonstra de que forma as normas brasileiras sobre o tema flexibilizam esse tipo de prática. Por fim, analisa quais são os critérios biojurídicos que devem ser aplicados para evitar práticas neoeugênicas que violem a dignidade humana e a preservação do patrimônio genético. Este artigo utilizou o método hipotético-dedutivo, com abordagem qualitativa, valendo-se de revisão bibliográfica de artigos científicos publicados em periódicos qualificados, bem como de obras paradigmáticas sobre o tema, além de análise de legislação e resoluções deontológicas.
RESPONSABILIDADE CIVIL DOS PAIS NOS CASOS DE HIPEREXPOSIÇÃO INFANTIL EM PLATAFORMAS DIGITAIS NO BRASIL
Authors: Baraúna Correia Amanda
Published: September 2023

RESUMO: Com a ampla adoção de plataformas digitais no Brasil, tem ocorrido um crescimento significativo da hiperexposição infantil, principalmente através da divulgação da imagem da criança pelos próprios pais. No entanto, essa prática tem se tornado um problema, uma vez que, quando ultrapassa limites, viola os direitos pessoais da criança. Portanto, o objetivo deste artigo é analisar as consequências jurídicas decorrentes dessa exposição excessiva, utilizando a  vulnerabilidade como princípio orientador, a fim de determinar se ela pode ser considerada um critério para a responsabilidade civil dos pais. Para isso, o tema foi abordado por meio de um método hipotético-dedutivo, com uma abordagem qualitativa, baseado em revisão bibliográfica de artigos científicos, obras relevantes sobre o assunto e nas legislações existentes, como a Constituição Federal de 1988, o Código Civil de 2002 e o Estatuto da Criança e do Adolescente, além de casos conhecidos atualmente e jurisprudências nacionais.

 

PALAVRAS-CHAVES: Hiperexposição infantil; Responsabilidade civil dos pais; Plataformas digitais; Vulnerabilidade; Direito da criança.

 

ABSTRACT: Due to the widespread use of digital platforms in Brazil, the overexposure of children, especially through the publicization of their images by parents, has been growing exponentially. However, this practice has become a problem, since, when boundaries are exceeded, it violates the child's personal rights. Thus, this article aims to analyze the legal implications arising from such excessive exposure, using vulnerability as a guiding principle to understand whether it can be considered a criterion for the parents' civil liability. For this purpose, the article applies a hypothetical-deductive method with a qualitative approach. The analysis relies on a literature review of scientific articles, important works on the subject, as well as existing legislations – such as the Federal Constitution of 1988, the Civil Code of 2002, and the Statute of the Child and Adolescent –, in addition to contemporary known cases and national jurisprudence.

KEYWORDS: Child overexposure; Parental civil liability; Digital platforms; Vulnerability.; Children's rights.
INFORMAÇÕES JURÍDICAS IMPRECISAS NA MÍDIA E REDES SOCIAIS.
Authors: Cunha Leandro Reinaldo da
Published: September 2023

Uma breve análise dos impactos da imprecisão da informações jurídicas para a sociedade.
APRESENTAÇÃO
Authors: Cunha Leandro Reinaldo da
Published: September 2023

Apresentação
ANALYSIS OF OPTICAL TOMOGRAPHY WITH NON-SCATTERING REGIONS
Authors: Hyvönen Nuutti
Published: July 2002

This paper provides mathematical analysis of optical tomography in a situation when the examined object, for example the human brain, is strongly scattering with non-scattering inclusions. Light propagation in biological tissue is often modelled by the diffusion approximation of the radiative transfer equation. To be justified, the diffusion approximation demands that the medium is strongly scattering. Naturally, this is not true for non-scattering inclusions, for which some other model is needed. This is found through geometrical optics. Combination of the two models leads to an elliptic partial differential equation with boundary conditions on the outer boundary as well as on the boundaries of the non-scattering regions. The well-posedness of this forward problem is the main concern of this work.

AMS 2000 Mathematics subject classification: Primary 35Q60; 35R30
The effects of selected sampling on the transmission disequilibrium test of a quantitative trait locus
Authors: DENG HONG-WEN , LI JING
Published: July 2002

We investigate how sampling of parents or children based on their extreme phenotypic values selected from clinical databases would affect the power of identification of quantitative trait loci (QTL) by a transmission disequilibrium test (TDT). We consider three selective sampling schemes based on the selection of phenotypic values of parents or children in nuclear families: (1) two children, one of extreme value, the other random; (2) two children extremely discordant; (3) one parent of extreme value. Other family members not specified will be recruited randomly with regard to phenotypic values. Our study shows that the second sampling scheme can always enhance the power for QTL identification, sometimes dramatically so. The increase in the statistical power of the TDT is particularly dramatic when h2 at the QTL under test is small or intermediate (e.g. 0·05 or 0·10). For the other two sampling schemes, under dominant effects at the QTL, the power is always increased relative to random sampling; however, under recessive or additive genetic effects, the power gain is generally minor or even decreased a little sometimes. Allele frequencies at the QTL and the selection stringency are important for determining the effect of selective sampling on the power of QTL identification. Our study is useful as a practical guideline on how to perform the TDT efficiently in practice by taking advantage of the extensive databases accumulated that are enriched with people of extreme phenotypic values.
Evolution of carbohydrate fraction in carbonated fermented milks as affected by β-galactosidase activity of starter strains
Authors: GUEIMONDE MIGUEL , CORZO NIEVES , VINDEROLA GABRIEL , REINHEIMER JORGE , DE LOS REYES-GAVILÁN CLARA G.
Published: July 2002

The influence of carbonation on the evolution of lactose, galactose and glucose in fermented milks with added probiotic bacteria (Lactobacillus casei, Lactobacillus acidophilus and/or Bifidobacterium bifidum) was evaluated and related to β-galactosidase activity of starter strains. During incubation and first days of refrigeration, lactose hydrolysis resulting in the liberation of galactose and glucose occurred in CT (Streptococcus thermophilus/Lb. casei), AT (Str. thermophilus/Lb. acidophilus) and ABT fermented milks (Str. thermophilus/Lb. acidophilus/Bifid. bifidum). Levels of galactose were higher than those of glucose and could be related to the preferential consumption of glucose by actively growing bacteria. Through the incubation, lactose and monosaccharide levels were not affected by milk carbonation. However, during refrigerated storage the presence of this gas was associated with slightly lower content of lactose and higher levels of galactose and glucose in AT and ABT products but not in CT fermented milks. Through the refrigeration galactose was moderately utilised by Lb. acidophilus in AT products whereas the presence of Bifid. bifidum seems to prevent the consumption of this sugar in ABT fermented milks. Glucose remained constant, with minor variations in CT products but a continuous increase of this sugar occurred in carbonated AT and ABT fermented milks during storage. β-Galactosidase activity displayed by Str. thermophilus strains was similar at pH 6·5 (initial pH of non-carbonated samples) and pH 6·3 (initial pH of carbonated samples) whereas Lb. acidophilus LaA3 showed greater β-galactosidase activity at pH 6·3 than at higher pH values. Thus, the enhanced metabolic activity of Lb. acidophilus caused by the low initial pH of carbonated milk also promoted higher cellular β-galactosidase activity that could have released greater amounts of galactose and glucose from lactose in AT and ABT fermented milks through the refrigerated period. In CT fermented milks, similar β-galactosidase activity levels of Str. thermophilus at pH 6·5 and 6·3 together with the absence of β-galactosidase activity in Lb. casei could explain the lack of differences on glucose and galactose content between carbonated and non-carbonated samples.
Structural features of bovine caseinomacropeptide A and B by 1H nuclear magnetic resonance spectroscopy
Authors: SMITH MARK H. , EDWARDS PATRICK J. B. , PALMANO KATE P. , CREAMER LAWRENCE K.
Published: July 2002

Samples of bovine caseinomacropeptide (CMP) were isolated from κ-casein A and κ-casein B and fractionated to give aglycosylated CMP A and CMP B and monoglycosylated CMP A. The secondary structures of these three peptides were compared under neutral and acidic (pH 4·2) conditions, using two-dimensional (2D) 1H nuclear magnetic resonance (NMR) spectroscopy. The differences between the spectra at pH 4·2 and 7·0 and the spectra of the aglycosylated and glycosylated CMP A were subtle, indicating little change in backbone conformation with these changes. These results suggest that differences in the coagulation properties of milks containing either κ-casein A or κ-casein B are more likely to be related to factors, such as micelle size or charge, than to structural differences arising from altered backbone conformation of the macropeptide segments of the κ-caseins.
Performance differences and cow responses in new milking parlours
Authors: HILLERTON J. ERIC , OHNSTAD IAN , BAINES JOHN R. , LEACH KATHARINE A.
Published: July 2002

The International Standards Organization (ISO) produces international standards
for milking equipment. These describe the minimum specifications of design,
installation, maintenance and testing of milking machines (BS ISO, 1996). Often
these standards are adopted and exceeded by national standards. Standards are
rarely mandatory and in some countries variations in interpretation and even
disagreement can lead to differences in operating conditions of the milking machine.

A survey of plant test results in the UK (Berry & Scrivens, 1997) showed that,
on annual or biannual testing, more than 75% of plants failed to meet the then
existing standard (BS5545, 1988). In the UK, most types of plant installed since 1994
meet the newest ISO standard (BS ISO, 1996). However, one type of plant has many
features different from all other types. This is a type of plant whose major variations
include a smaller claw bowl volume (150 ml), a narrower long milk tube diameter
(13·5 mm), 8 mm milk pulse tube, greater cluster weight (approximately 3·5 kg) and
simultaneous pulsation used on a plant with milk lift and milking at an installed
system vacuum of 47–48 kPa. The majority of parlours installed with this equipment
at the time of this study had no form of indexing (see below).

A study has been undertaken to assess 20 new installations for compliance with
the ISO requirements (BS ISO, 1996), performance in a static test, milking
performance, cow behaviour and the effects on teat condition. Compliance to
standards and static test results have been reported elsewhere (Ohnstad, 1997), with
no plant proving entirely satisfactory. Some plants had major problems with
vacuum level, pulsation characteristics and large air leaks. The physical operation of
the milking plant has important implications for cow behaviour and welfare and also
ergonomics of the milking operation. The effects on teat condition have already been
reported (Hillerton et al. 2000). Here the effects on cow behaviour and milking
performance are assessed. Comparisons have been made in line with the International
Dairy Federation recommendations (IDF, 1997) to examine the performance and
interactions of the cow, the machine and the operator in evaluating the milking
process.
15N as a marker to assess portal absorption of nitrogen from milk, yogurt and heat-treated yogurt in the growing pig
Authors: RYCHEN GUIDO , MPASSI DIDIER , JURJANZ STEPHAN , MERTES MICHEL , LENOIR-WIJNKOOP IRENE , ANTOINE JEAN MICHEL , LAURENT FRANÇOIS
Published: July 2002

Milk and yogurt constitute a major source of dietary protein. The nutritive value
of dietary proteins is linked to subsequent postprandial amino acid availability in the
portal blood (Rérat, 1988). Portal absorption of nutrients cannot be studied in
humans, but pigs provide a valid model for studying protein digestion in humans
(Rowan et al. 1994).

Since stable isotopes are suitable to distinguish the exogenous from endogenous
protein fraction in the intestinal lumen, intrinsic isotopic labelling of milk proteins
has been considered a useful technique for nutritional investigations (Gaudichon et
al. 1995; Gaudichon et al. 1999; Mahé et al. 1994). Recently, the use of
15N-labelled
milk proteins were used to distinguish exogenous from endogenous N fractions in the
human intestine after ingestion of 15N-milk or 15N-yogurt (Gaudichon et al. 1995).
These authors pointed out that the jejunal flux of 15N was different for milk and
yogurt. It is known that milk proteins and lactose undergo preliminary hydrolysis
during lactic fermentation (Tamine & Deeth, 1980). It is also suggested that lactic
fermentation enhances the nutritional value of milk proteins (Vass et al. 1984).
Response of turbulent boundary layers to multiple strain rates
Authors: SCHWARZ A. C. , PLESNIAK M. W. , MURTHY S. N. B.
Published: July 2002

Many practical applications, such as in blade cascades and turbomachinery, involve
inhomogeneous turbulent shear flows subjected simultaneously to multiple strains. In
principle, the applied strain can be combined to yield an effective strain. However,
no simple stress–strain relation is capable of establishing turbulent stress or energy
balance in the mean or on an instantaneous basis. In the current investigation, a
turbulent boundary layer is examined in the presence of convex curvatures of different
strengths combined with streamwise (favourable and adverse) pressure gradients,
with various values of pressure gradient ratio, (∂P/∂s)/(∂P/∂n). Measurements of
the mean and turbulent parameters and flux Richardson number show appreciable
changes, mainly in the outer portion of the boundary layer (y+ > 100). The turbulent
burst frequency, particularly at the location of application of the additional strain
rate, also changes relative to its value with wall curvature alone.

Three primary observations from these experiments are as follows: (i) in all cases,
the mean velocity profile and all of the measured Reynolds stresses collapse in
the near-wall region using standard inner scaling; (ii) the applied strains combine
nonlinearly, with one of the strains dominating the local flow during its development;
(iii) the ratio of the radial to axial pressure gradient magnitude influences both
classical turbulence correlations and mean flow, as well as the physical production
cycle of turbulence; and (iv) application rate of newly introduced strain rates is at
least as important as their magnitudes.
Integral flow properties of the swash zone and averaging.
Part 2. Shoreline boundary conditions
for wave-averaged models
Authors: BROCCHINI M. , BELLOTTI G.
Published: July 2002

Shoreline boundary conditions for nearshore hydrodynamic models are discussed
on the basis of the swash zone equations of Brocchini & Peregrine (1996). Swash
zone flows are investigated further using the shallow water equations. Results from
numerical computations are used to guide approximation to provide more practical
boundary conditions for wave-averaged flows. Approximate boundary conditions,
valid for small values of the rate of change of the mean water volume in the swash
zone, are found which allow explicit computation of a non-zero mean water depth at
the mean shoreline. This is computed in terms of the local height of the short waves.
Implementation issues are also discussed.
On gravity currents propagating at the base of a stratified ambient
Authors: UNGARISH MARIUS , HUPPERT HERBERT E.
Published: July 2002

The behaviour of an inviscid gravity current which is released from behind a lock
and then propagates over a horizontal boundary at the base of a stratified ambient
fluid is considered. An extension of the shallow-water formulation for a homogeneous
ambient to the stratified case is developed, without using any additional adjustable
parameters. Attention is focused on the initial ‘slumping’ stage of a rectangular current
which is typified by a constant speed of propagation. The analytical results are in
good agreement with, and give a firm theoretical interpretation of, the corresponding
experiments and numerical simulations of Maxworthy et al. (2002). Finite-difference
solutions of the Navier–Stokes equations, using a different technique from that used
by Maxworthy et al. (2002), are also presented and provide both good agreement
with their results and further validation of the present shallow-water approach. The
differences between currents in a homogeneous and stratified ambient, and possible
implementation of the results to other configurations, are discussed.
Wave interaction with a vertical cylinder:
spanwise flow patterns and loading
Authors: YANG Y. , ROCKWELL D.
Published: July 2002

A vertical cylinder is located in a free-surface wave, and a two-camera version
of high-image-density particle image velocimetry is employed to characterize the
spanwise modes of the flow structure in terms of instantaneous velocity and vorticity.
These modes are classified according to organized patterns of velocity in the near
wake, and are further interpreted in terms of distinctive arrangements of streamwise
vorticity concentrations.

At low Keulegan–Carpenter number, which corresponds to small wave height,
locally two-dimensional vortices having small scale and circulation tend to form as
a symmetrical pair and remain attached, or in close proximity, to the surface of the
cylinder. Along the span of the cylinder, the near wake shows either a sinuous S or
a unidirectional U mode. The spanwise wavelength λ of the S modes, relative to the
cylinder diameter D, lies in the range 1 [lsim ] λ/D [lsim ] 4:5. These values of λ/D represent
the spacing between extrema of patterns of cross flow velocity, as well as between
clusters of streamwise vorticity of like sign. As the free surface is approached, the
value of λ/D scales with the ratio of the minor to major axes of the elliptical particle
trajectory of the wave.

At moderate values of the Keulegan–Carpenter number, locally two-dimensional
vortices having large scale and circulation are shed from the cylinder in an asymmetric
arrangement. The corresponding spanwise mode represents the phase variation of this
shedding along the span of the cylinder. These sinuous S modes involve large-scale
distortions of patterns of both cross flow velocity and streamwise vorticity, which
have wavelengths in the range 10 [lsim ] λ/D [lsim ] 110, in contrast to the spacing between
individual concentrations of vorticity, which is 1:5D to 4D. Remarkably, it is possible
to attain a unidirectional U mode, whereby the phase of the locally two-dimensional
vortex shedding is preserved along the entire extent of the cylinder.
Signatures of the moments due to the transverse and in-line forces on the cylinder
were acquired simultaneously with the patterns of instantaneous velocity and vorticity.
Severe modulations of the moment due to the transverse force are associated with
spontaneous transformations between basic forms of the sinuous S and unidirectional
U modes. The overall form of the signature of the moment due to the in-line force is,
however, not generally affected by the spontaneous transformation between modes,
but distortion of its peaks is evident.
Vortex multipoles in two-layer rotating
shallow-water flows
Authors: BAEY JEAN-MICHEL , CARTON XAVIER
Published: July 2002

The stability of elliptically perturbed circular vortices is investigated in a two-layer
shallow-water model, with constant background rotation. The fluid is bounded above
and below by rigid and at surfaces. The linear stability analysis shows that elliptical
perturbations are most unstable for moderate Burger numbers and vorticity
shears. Shorter waves dominate for more sheared vortices. Shallow-water and
quasi-geostrophic growth rates exhibit a striking similarity, except at each end of the Burger
number domain. There, cyclones (anticyclones) with finite Rossby numbers are more
(less) unstable than their quasi-geostrophic counterparts. A simple model gives a
first-order trend for this bias.

Nonlinear model runs with initially perturbed vortices also show the similarity
between the two dynamics. In these runs, elliptically deformed vortices stabilize as
stationary rotating tripoles for moderate linear instability; on the other hand, strongly
unstable vortices break as dipoles. During these nonlinear processes, energy transfers
indicate that barotropic instability is at least as active as the baroclinic one. For tripole
formation, the modal analysis of the perturbation exhibits a dominant contribution
of the original wave and of the mean flow correction. The ageostrophic and divergent
parts of the flow are respectively weak and negligible. The Lighthill equation proves
that few internal gravity waves are generated during tripole formation or dipolar
breaking. Finally, the effects of triangular perturbations on circular vortices and the
formation of quadrupoles are briefly addressed.
Expansion dynamics of volatile-supersaturated
liquids and bulk viscosity of bubbly magmas
Authors: LENSKY N. G. , LYAKHOVSKY V. , NAVON O.
Published: July 2002

We derive expressions for the bulk viscosity of suspension of gas bubbles in an
incompressible Newtonian liquid that exsolves volatiles. The suspension is modelled
as close packed spherical cells and is represented by a single cell (‘cell model’). A cell,
consisting of a gas bubble centred in a spherical shell of a volatile-bearing liquid,
is subjected to decompression that is applied at the cell boundary, and the resulting
dilatational boundary motion and driving pressure are obtained. The dilatational
motion and the driving pressure are used to define the bulk viscosity of the cell, as
if it were composed of a homogeneously compressible fluid. By definition, the bulk
viscosity is the relation between changes of the driving pressure and changes in the
resulting expansion strain rate. The bulk viscosity of the suspension is obtained in
terms of two-phase parameters, i.e. bubble radius, gas pressure and the properties
of the incompressible continuous liquid phase. The resulting bulk viscosity is highly
nonlinear. At the beginning of the expansion process, when gas exsolution is efficient,
the expansion rate grows exponentially while the driving pressure decreases slightly,
which means that the bulk viscosity is formally negative. This negative value reflects
the release of the energy stored in the supersaturated liquid and its transfer to
mechanical work during exsolution. Later, when bubbles are large and the gas influx
decreases significantly, the strain rate decelerates and the bulk viscosity becomes
positive as expected in a dissipative system. We demonstrate that amplification of
seismic waves travelling through a volcanic conduit filled with a volatile saturated
magma may be attributed to the negative bulk viscosity of the compressible magma.
Amplification of an expansion wave may, at some level in the conduit, damage the
conduit walls and initiate the opening of a new pathway for magma eruption. We
also consider the energy related to positive and negative bulk viscosities.
Spreading and peeling dynamics in a model of
cell adhesion
Authors: HODGES S. R. , JENSEN O. E.
Published: July 2002

To understand how viscous and elastic membrane forces mediate the adhesion of
fluid-borne cells to biological surfaces under the action of specific receptor–ligand
bonds, we consider a model problem in which a two-dimensional cell interacts with a
plane adhesive surface. The cell is modelled as an extensible membrane under tension
containing fluid of constant volume. Assuming rapid binding kinetics, molecular
binding forces are described through a contact potential that is long-range attractive
but short-range repulsive. Using lubrication theory to describe the thin-film flow
between the cell and the plane, we model sedimentation of the cell onto the plane
under adhesive forces, followed by removal of the cell from the plane under the action
of an external force. Numerical simulations show how these events are dominated
respectively by quasi-steady spreading and peeling motions, which we capture using
an asymptotic analysis. The analysis is extended to model a cell tank-treading over an
adhesive wall in an external shear flow. The relation between cell rolling speed and
shear rate is determined: at low speeds it is linear and independent of the viscosity
of the suspending fluid; at higher speeds it is nonlinear and viscosity-dependent.
Laminar flow past a sphere rotating in the
streamwise direction
Authors: KIM DONGJOO , CHOI HAECHEON
Published: July 2002

Numerical simulations are conducted for laminar flow past a sphere rotating in
the streamwise direction, in order to investigate the effect of the rotation on the
characteristics of flow over the sphere. The Reynolds numbers considered are Re = 100,
250 and 300 based on the free-stream velocity and sphere diameter, and the
rotational speeds are in the range of 0 [les ] ω* [les ] 1, where ω* is the maximum azimuthal
velocity on the sphere surface normalized by the free-stream velocity. At ω* = 0
(without rotation), the flow past the sphere is steady axisymmetric, steady planar-symmetric,
and unsteady planar-symmetric, respectively, at Re = 100, 250 and 300.
Thus, the time-averaged lift forces exerted on the stationary sphere are not zero
at Re = 250 and 300. When the rotational speed increases, the time-averaged drag
force increases for the Reynolds numbers investigated, whereas the time-averaged lift
force is zero for all ω* > 0. On the other hand, the lift force fluctuations show a
non-monotonic behaviour with respect to the rotational speed. At Re = 100, the flow
past the sphere is steady axisymmetric for all the rotational speeds considered and
thus the lift force fluctuation is zero. At Re = 250 and 300, however, the flows are
unsteady with rotation and the lift force fluctuations first decrease and then increase
with increasing rotational speed, showing a local minimum at a specific rotational
speed. The vortical structures behind the sphere are also significantly modified by the
rotation. For example, at Re = 300, the flows become ‘frozen’ at ω* = 0.5 and 0.6,
i.e. the vortical structures in the wake simply rotate without temporal variation of
their strength and the magnitude of the instantaneous lift force is constant in time.
It is shown that the flow becomes frozen at higher rotational speed with increasing
Reynolds number. The rotation speed of the vortical structures is shown to be slower
than that of the sphere.
Free-surface flows emerging from beneath a
semi-infinite plate with constant vorticity
Authors: McCUE SCOTT W. , FORBES LAWRENCE K.
Published: July 2002

The free-surface flow past a semi-infinite horizontal plate in a finite-depth fluid is
considered. It is assumed that the fluid is incompressible and inviscid and that the
flow approaches a uniform shear flow downstream. Exact relations are derived using
conservation of mass and momentum for the case where the downstream free surface
is flat. The complete nonlinear problem is solved numerically using a boundary-integral
method and these waveless solutions are shown to exist only when the height
of the plate above the bottom is greater than the height of the uniform shear flow.
Interesting results are found for various values of the constant vorticity. Solutions
with downstream surface waves are also considered, and nonlinear results of this type
are compared with linear results found previously. These solutions can be used to
model the flow near the stern of a (two-dimensional) ship.