9,305 research outputs found

    A structural systems biology approach for quantifying the systemic consequences of missense mutations in proteins

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    Gauging the systemic effects of non-synonymous single nucleotide polymorphisms (nsSNPs) is an important topic in the pursuit of personalized medicine. However, it is a non-trivial task to understand how a change at the protein structure level eventually affects a cell's behavior. This is because complex information at both the protein and pathway level has to be integrated. Given that the idea of integrating both protein and pathway dynamics to estimate the systemic impact of missense mutations in proteins remains predominantly unexplored, we investigate the practicality of such an approach by formulating mathematical models and comparing them with experimental data to study missense mutations. We present two case studies: (1) interpreting systemic perturbation for mutations within the cell cycle control mechanisms (G2 to mitosis transition) for yeast; (2) phenotypic classification of neuron-related human diseases associated with mutations within the mitogen-activated protein kinase (MAPK) pathway. We show that the application of simplified mathematical models is feasible for understanding the effects of small sequence changes on cellular behavior. Furthermore, we show that the systemic impact of missense mutations can be effectively quantified as a combination of protein stability change and pathway perturbation

    University and College Admission Policies and Practices in Hong Kong: Opportunities and Challenges in Moving from Secondary to Tertiary Education

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    Conference Theme: Transition to a Better and Higher LearningTopic II: The Transition from Secondary to Higher Education : Case study presentationsⅠpublished_or_final_versio

    A Self-Consistent Model for Positronium Formation from Helium Atoms

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    The differential and total cross sections for electron capture by positrons from helium atoms are calculated using a first-order distorted wave theory satisfying the Coulomb boundary conditions. In this formalism a parametric potential is used to describe the electron screening in a consistent and realistic manner. The present procedure is self consistent because (i) it satisfies the correct boundary conditions and post-prior symmetry, and (ii) the potential and the electron binding energies appearing in the transition amplitude are consistent with the wave functions describing the collision system. The results are compared with the other theories and with the available experimental measurements. At the considered range of collision energies, the results agree reasonably well with recent experiments and theories. [Note: This paper will be published on volume 42 of the Brazilian Journal of Physics

    An assessment of pulse transit time for detecting heavy blood loss during surgical operation

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    Copyright @ Wang et al.; Licensee Bentham Open. This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.The main contribution of this paper is the use of non-invasive measurements such as electrocardiogram (ECG) and photoplethysmographic (PPG) pulse oximetry waveforms to develop a new physiological signal analysis technique for detecting blood loss during surgical operation. Urological surgery cases were considered as the control group due to its generality, and cardiac surgery as experimental group since it involves blood loss and water supply. Results show that the control group has the tendency of a reduction of the pulse transient time (PTT), and this indicates an increment in the blood flow velocity changes from slow to fast. While for the experimental group, the PTT indicates high values during blood loss, and low values during water supply. Statistical analysis shows considerable differences (i.e., P <0.05) between both groups leading to the conclusion that PTT could be a good indicator for monitoring patients' blood loss during a surgical operation.The National Science Council (NSC) of Taiwan and the Centre for Dynamical Biomarkers and Translational Medicine, National Central University, Taiwan

    Dynamic Effects of Axial Loading on the Lumbar Spine During Magnetic Resonance Imaging in Patients with Suspected Spinal Stenosis

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    BackgroundPrevious studies have shown that axial compression in extension (ACE) of the spine during magnetic resonance imaging (MRI) has revealed unexpected pathological features compared with the conventional psoas-relaxed position (PRP) used in imaging. The purpose of this study was to evaluate the dynamic effect of axial loading on lumbar spinal stenosis using MRI in patients with spinal stenosis.MethodsA total of 14 women and 11 men with lumbar spinal stenosis were examined in both PRP and ACE positions. We calculated the dural-sac cross-sectional area (DCSA) to evaluate severity of spinal canal stenosis. DCSA, as well as the dural-sac anteroposterior diameter (DAPD) and dural-sac transverse diameter (DTD) in both positions were measured using a digital image view station. A paired t test determined the differences in DCSA, DAPD and DTD between the two positions at each intervertebral disc level.ResultsAxial loading increased severity of lumbar spinal stenosis during MRI, as demonstrated by a decrease in DCSA from 20.5% to 6.3% (mean, 11.40 ± 3.66%) between the PRP and ACE positions (p < 0.01). Significant differences were also noted in DAPD and DTD between the PRP and ACE positions (p < 0.01). A significant correlation was found between the decrease in mean DCSA and that in DAPD and DTD. The decrease in mean DCSA, DAPD and DTD following axial compression was greatest at the L4/5 and L5/S1 levels.ConclusionAxial loading increases severity of lumbar canal stenosis and the effect of axial loading on MRI examination is greatest at the L4/5 and L5/S1 levels

    Želatinski film s mikrokapsulama antocijana izoliranih iz plavog graška (Clitoria ternatea) kao prehrambena ambalaža s učinkom suzbijanja patogenih mikroorganizama

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    Research background. Microbial contamination of food products is one of the significant causes of food spoilage and foodborne illnesses. The use of active packaging films incorporated with antimicrobial agents can be a measure to improve food quality and extend shelf life. Nevertheless, antimicrobial agents such as silver, copper, titanium and zinc in the packaging films have raised concerns among consumers due to toxicity issues. Experimental approach. The current study aims to develop biodegradable gelatine-based edible films incorporated with microcapsules of Clitoria ternatea-derived anthocyanins as a natural antimicrobial agent. The impact of incorporation of microcapsules with anthocyanins on the morphology, thermal, mechanical, water vapour barrier and physicochemical properties of the gelatine films was evaluated in this study. The effectiveness of the developed films against foodborne pathogens and their application for perishable food protection were also investigated. Results and conclusions. The results show that incorporating anthocyanin microcapsules enhances the gelatine film physical and mechanical properties by increasing the thickness, tensile strength, Young\u27s modulus and elongation at break of the films. Scanning electronic microscopy analysis revealed that the film surface morphology with anthocyanin microcapsules had a homogeneous and smooth surface texture compared to the control. The thermogravimetric analysis also showed a slight improvement in the thermal properties of the developed films. Agar well diffusion assay revealed that the developed films exhibit significant inhibition against a broad-spectrum of bacteria. Furthermore, the films composed of gelatine with anthocyanin microcapsules significantly reduced the total viable count of microorganisms in the bean curd during storage for 12 days compared with the control films. Novelty and scientific contribution.Increasing global awareness of healthy and safe food with minimal synthetic ingredients as preservatives has sparked the search for the use of antimicrobial agents of natural origins in active food packaging material. In this study, a safe and effective active packaging film was developed using an environmentally friendly biopolymer, gelatine film incorporated with microcapsules of Clitoria ternatea-derived anthocyanins as a natural antimicrobial agent. This study demonstrated that such a method is not only able to improve the film physical properties but can also significantly prolong the shelf life of food products by protecting them from microbial spoilage.Pozadina istraživanja. Mikrobna kontaminacija je jedan od važnijih uzroka kvarenja hrane i pojave bolesti koje se prenose hranom. Primjenom aktivnih filmova za pakiranje hrane obogaćenih antimikrobnim agensima može se poboljšati kakvoća hrane i produljiti njezina valjanost. No, potrošači su sve više zabrinuti zbog moguće toksičnosti mnogih antimikrobnih agensa koji se primjenjuju u tim filmovima, kao što su srebro, bakar, titan i cink. Eksperimentalni pristup. Svrha je ovoga rada bila izraditi biorazgradive jestive filmove od želatine obogaćene mikrokapsulama antocijana izoliranih iz plavog graška (Clitoria ternatea) kao prirodnih antimikrobnih agensa. Ispitan je utjecaj mikrokapsula s antocijanima na morfologiju, toplinska, mehanička i fizikalno-kemijska svojstva filmova, te njihovu propusnost vodene pare. Također je ispitan učinak dobivenih filmova na patogene mikroorganizme u hrani i zaštitu lako pokvarljivih proizvoda. Rezultati i zaključci. Rezultati pokazuju da su se fizikalna i mehanička svojstva filmova poboljšala s dodatkom mikrokapsula antocijana, koje su povećale gustoću, vlačnu čvrstoću, Youngov modul elastičnosti i istezljivost filma. Ispitivanjem morfoloških značajki pretražnom elektronskom mikroskopijom utvrđeno je da film obogaćen antocijanima imao homogenu i glatku površinu, za razliku od kontrolnog uzorka. Termogravimetrijskom je analizom potvrđeno blago poboljšanje toplinskih svojstava filmova. Difuzijom u jažicama agara otkriveno je da dobiveni filmovi imaju znatan inhibicijski učinak na širok spektar bakterija. Osim toga, filmovi od želatine s dodatkom mikrokapsula antocijana smanjili su ukupni broj živih stanica mikroorganizama u tofuu tijekom 12 dana skladištenja, u usporedbi s kontrolnim uzorcima. Novina i znanstveni doprinos. Veća svijest ljudi o važnosti zdrave i sigurne prehrane sa što manjim udjelom sintetičkih konzervansa potakla je potragu za antimikrobnim agensima iz prirodnih izvora koji se mogu upotrijebiti u materijalima za aktivno pakiranje hrane. U ovom je radu razvijen siguran i učinkovit aktivni ambalažni film s dodatkom ekološki prihvatljivog biopolimera, želatinskog filma obogaćenog mikrokapsulama antocijana izoliranih iz plavog graška (Clitoria ternatea) kao prirodnih antimikrobnih agensa. Istraživanje je pokazalo da se ovom metodom mogu poboljšati fizikalna svojstva filma, ali i bitno produljiti vrijeme skladištenja hrane, jer ih dobiveni film štiti od mikrobnog kvarenja
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