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1.
Environ Pollut ; 345: 123392, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38253162

RESUMO

As the world's demand for textiles and clothing rapidly increases, this industry's greenhouse gas (GHG) emissions are becoming a major environmental concern. Bangladesh, a key player in the global textile supply chain and one of the top producers, contributes significantly to these emissions. However, accessible data on activity and GHG emissions, crucial for researchers, the private sector, and policymakers in decision-making, is scarce. To address this gap, this study combines a detailed field survey with expert interviews to establish a comprehensive emission inventory. This inventory aims to identify hotspots and facilitate the adoption of effective mitigation strategies. Focusing on a prominent industrial zone's textile and readymade garments (RMG) industries, the research employs a mix of top-down and bottom-up approaches and follows the IPCC guidelines to develop a GHG emission inventory for 2022. The study evaluates various emission sources, including scope 1 (onsite fuel combustions), scope 2 (grid electricity usage), and scope 3 (waste and wastewater treatment). In the total emissions (6043.5 Gg CO2eq.), textile and RMG industries contribute 67.8% and 32.2%, respectively, with scope 1 emissions dominating at 85%. Notably, scope 2 emissions exhibit significant uncertainty (-10.4% to +11.9%), largely due to variations in national grid emission factors. This study forecasts GHG emissions until 2030, considering current trends (26 thousand Gg CO2 eq.). It also explores various energy mix scenarios, factoring in the depletion of existing natural gas reserves (ranging from 8 thousand to 33 thousand Gg CO2 eq.). This study delves into the impact of the Environmental, Social, and Governance (ESG) system on industries' GHG emissions. Besides improving worldwide emission databases and identifying hotspots, this research aims to promote a sustainable transition in both Bangladesh and other developing textile manufacturing nations across the globe.


Assuntos
Gases de Efeito Estufa , Gases de Efeito Estufa/análise , Efeito Estufa , Dióxido de Carbono/análise , Bangladesh , Vestuário
2.
J Chem Inf Model ; 63(5): 1570-1577, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36858485

RESUMO

In-cell protein-protein association, which is crucial in enzyme catalysis and polymerization, occurs in an environment that is highly heterogeneous and crowded. The crowder molecules exclude the reactant molecules from occupying certain regions of the cell, resulting in changes in the reaction thermodynamics and kinetics. Recent studies, both experiment and simulations, revealed that the nature of the interaction between crowder and protein species, in particular the soft interactions, plays an important role in crowder induced effects on protein association. To this end, from a simulation perspective, it is important to decipher the level of structural resolution in a protein-crowder model that can faithfully capture the influence of crowding on protein association. Here, we investigate the dimerization of model system GB1 in the presence of lysozyme crowders at two structural resolutions. The lower resolution model assumes both protein and crowder species as spherical beads, similar to the analytical scaled particle theory model, whereas the higher resolution model retains residue specific structural details for protein and crowder species. From the higher resolution model, it is found that GB1 dimer formation is destabilized in the presence of lysozyme crowders, and the destabilization is more for the side-by-side dimer compared to the domain-swapped dimer, in qualitative agreement with experimental findings. However, the low resolution CG model predicts stabilization of the dimers in the presence of the lysozyme crowder, similar to the SPT model. Our results indicate a nontrivial role of the choice of model resolution in computer simulation studies investigating crowder induced effects.


Assuntos
Muramidase , Proteínas , Muramidase/química , Simulação por Computador , Dimerização , Termodinâmica
3.
J Biol Chem ; 299(5): 104653, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36990217

RESUMO

Accumulating evidence suggests that amyloid plaque-associated myelin lipid loss as a result of elevated amyloid burden might also contribute to Alzheimer's disease. The amyloid fibrils are closely associated with lipids under physiological conditions; however, the progression of membrane remodeling events leading to lipid-fibril assembly remains unknown. Here we first reconstitute the interaction of amyloid Beta 40 (Aß-40) with myelin-like model membrane and show that the binding of Aß-40 induces extensive tubulation. To look into the mechanism of membrane tubulation, we chose a set of membrane conditions varying in lipid packing density and net charge that allows us to dissect the contribution of lipid specificity of Aß-40 binding, aggregation kinetics, and subsequent changes in membrane parameters such as fluidity, diffusion, and compressibility modulus. We show that the binding of Aß-40 depends predominantly on the lipid packing defect densities and electrostatic interactions and results in rigidification of the myelin-like model membrane during the early phase of amyloid aggregation. Furthermore, elongation of Aß-40 into higher oligomeric and fibrillar species leads to eventual fluidization of the model membrane followed by extensive lipid membrane tubulation observed in the late phase. Taken together, our results capture mechanistic insights into snapshots of temporal dynamics of Aß-40-myelin-like model membrane interaction and demonstrate how short timescale, local phenomena of binding, and fibril-mediated load generation results in the consequent association of lipids with growing amyloid fibrils.


Assuntos
Peptídeos beta-Amiloides , Lipídeos , Bainha de Mielina , Humanos , Doença de Alzheimer/metabolismo , Amiloide/química , Amiloide/metabolismo , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Lipídeos/química , Bainha de Mielina/química , Bainha de Mielina/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo
4.
IEEE J Biomed Health Inform ; 26(10): 4826-4836, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35439153

RESUMO

Due to numerous hardware shortcomings, medical image acquisition devices are susceptible to producing low-quality (i.e., low contrast, inappropriate brightness, noisy, etc.) images. Regrettably, perceptually degraded images directly impact the diagnosis process and make the decision-making manoeuvre of medical practitioners notably complicated. This study proposes to enhance such low-quality images by incorporating end-to-end learning strategies for accelerating medical image analysis tasks. To the best concern, this is the first work in medical imaging which comprehensively tackles perceptual enhancement, including contrast correction, luminance correction, denoising, etc., with a fully convolutional deep network. The proposed network leverages residual blocks and a residual gating mechanism for diminishing visual artefacts and is guided by a multi-term objective function to perceive the perceptually plausible enhanced images. The practicability of the deep medical image enhancement method has been extensively investigated with sophisticated experiments. The experimental outcomes illustrate that the proposed method could outperform the existing enhancement methods for different medical image modalities by 5.00 to 7.00 dB in peak signal-to-noise ratio (PSNR) metrics and 4.00 to 6.00 in DeltaE metrics. Additionally, the proposed method can drastically improve the medical image analysis tasks' performance and reveal the potentiality of such an enhancement method in real-world applications.


Assuntos
Aumento da Imagem , Processamento de Imagem Assistida por Computador , Humanos , Aumento da Imagem/métodos , Processamento de Imagem Assistida por Computador/métodos , Razão Sinal-Ruído
5.
Ann Card Anaesth ; 25(1): 97-99, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35075030

RESUMO

Persistent poststernotomy pain (PSP) is a well-known entity following cardiac surgery done with midline strenotomy. The severity of pain is usually mild to moderate in the majority of the patients. However, a small percentage of patients develop severe and persistent pain and need aggressive treatment. Our patient, a 63-year-old lady developed chronic severe parasternal pain following coronary artery bypass graft surgery. As multiple medications did not relieve her pain effectively, we did an ultrasound-guided pectoral-intercostal fascial plane block to which she responded with excellent and long-lasting pain relief. This is the first such case report of the use of this novel block technique for treating PSP.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Dor Crônica , Bloqueio Nervoso , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Dor Crônica/terapia , Feminino , Humanos , Pessoa de Meia-Idade , Bloqueio Nervoso/métodos , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/etiologia , Esternotomia/efeitos adversos
6.
J Mol Graph Model ; 107: 107936, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34139641

RESUMO

Protein-protein association in vivo occur in a crowded and complex environment. Theoretical models based on hard-core repulsion predict stabilization of the product under crowded conditions. Soft interactions, on the contrary, can either stabilize or destabilize the product formation. Here we modeled protein association in presence of crowders of varying size, shape, interaction potential and used different mixing parameters for constituent crowders to study the influence on the association reaction. It was found that size is a more dominant factor in crowder-induced stabilization than the shape. Furthermore, in a mixture of crowders having different sizes but identical interaction potential, the change of free energy is additive of the free energy changes produced by individual crowders. However, the free energy change is not additive if two crowders of same size interact via different interaction potentials. These findings provide a systematic understanding of crowding influences in heterogeneous medium.


Assuntos
Proteínas , Difusão
7.
J Phys Chem B ; 122(21): 5508-5514, 2018 05 31.
Artigo em Inglês | MEDLINE | ID: mdl-29338243

RESUMO

Enhanced sampling techniques represent a versatile approach to account for rare conformational transitions in biomolecules. A particularly promising strategy is to combine massive parallel computing of short molecular dynamics (MD) trajectories (to sample the free energy landscape of the system) with Markov state modeling (to rebuild the kinetics from the sampled data). To obtain well-distributed initial structures for the short trajectories, it is proposed to employ metadynamics MD, which quickly sweeps through the entire free energy landscape of interest. Being only used to generate initial conformations, the implementation of metadynamics can be simple and fast. The conformational dynamics of helical peptide Aib9 is adopted to discuss various technical issues of the approach, including metadynamics settings, minimal number and length of short MD trajectories, and the validation of the resulting Markov models. Using metadynamics to launch some thousands of nanosecond trajectories, several Markov state models are constructed that reveal that previous unbiased MD simulations of in total 16 µs length cannot provide correct equilibrium populations or qualitative features of the pathway distribution of the short peptide.


Assuntos
Cadeias de Markov , Peptídeos/química , Simulação de Dinâmica Molecular , Peptídeos/metabolismo , Análise de Componente Principal , Termodinâmica
8.
Data Brief ; 12: 103-107, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28409178

RESUMO

BanglaLekha-Isolated, a Bangla handwritten isolated character dataset is presented in this article. This dataset contains 84 different characters comprising of 50 Bangla basic characters, 10 Bangla numerals and 24 selected compound characters. 2000 handwriting samples for each of the 84 characters were collected, digitized and pre-processed. After discarding mistakes and scribbles, 1,66,105 handwritten character images were included in the final dataset. The dataset also includes labels indicating the age and the gender of the subjects from whom the samples were collected. This dataset could be used not only for optical handwriting recognition research but also to explore the influence of gender and age on handwriting. The dataset is publicly available at https://data.mendeley.com/datasets/hf6sf8zrkc/2.

9.
J Chem Phys ; 145(18): 184114, 2016 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-27846702

RESUMO

Molecular dynamics simulations of biomolecular processes are often discussed in terms of diffusive motion on a low-dimensional free energy landscape F(𝒙). To provide a theoretical basis for this interpretation, one may invoke the system-bath ansatz á la Zwanzig. That is, by assuming a time scale separation between the slow motion along the system coordinate x and the fast fluctuations of the bath, a memory-free Langevin equation can be derived that describes the system's motion on the free energy landscape F(𝒙), which is damped by a friction field and driven by a stochastic force that is related to the friction via the fluctuation-dissipation theorem. While the theoretical formulation of Zwanzig typically assumes a highly idealized form of the bath Hamiltonian and the system-bath coupling, one would like to extend the approach to realistic data-based biomolecular systems. Here a practical method is proposed to construct an analytically defined global model of structural dynamics. Given a molecular dynamics simulation and adequate collective coordinates, the approach employs an "empirical valence bond"-type model which is suitable to represent multidimensional free energy landscapes as well as an approximate description of the friction field. Adopting alanine dipeptide and a three-dimensional model of heptaalanine as simple examples, the resulting Langevin model is shown to reproduce the results of the underlying all-atom simulations. Because the Langevin equation can also be shown to satisfy the underlying assumptions of the theory (such as a delta-correlated Gaussian-distributed noise), the global model provides a correct, albeit empirical, realization of Zwanzig's formulation. As an application, the model can be used to investigate the dependence of the system on parameter changes and to predict the effect of site-selective mutations on the dynamics.


Assuntos
Alanina/química , Alanina/metabolismo , Simulação de Dinâmica Molecular , Difusão , Conformação Molecular , Termodinâmica
10.
J Phys Chem B ; 119(34): 11275-86, 2015 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-26125118

RESUMO

The design of optimal photoswitches to regulate nucleic acid functionality is a considerable challenge. Azobenzene switches that are covalently bound to the nucleic acid backbone are a paradigm example that has been studied using different types of linker species connecting the chromophore to the backbone. To support experimental efforts to construct optimal azobenzene-linker-RNA combinations, we introduce here a systematic approach for theoretical analysis, which provides criteria for the local embedding of the chromophore via a chosen linker. Using a local reference frame adapted to the chromophore, quantitative measures are provided for (i) the propensity of stacking in competition with a drift toward the minor or major groove, (ii) the tendency to disrupt the native hydrogen bond network, (iii) the structural flexibility of the chromophore-linker combination, and (iv) the correlations with the presence of a base in the opposite strand. Large differences in structural stability between the trans and cis forms of the azobenzene chromophore, according to these criteria, indicate good functionality and lead to significant differences in melting temperatures. In particular, a recently synthesized deoxyribose linker proves optimal within the set of azobenzene-linker-RNA combinations considered.


Assuntos
Compostos Azo/química , Simulação de Dinâmica Molecular , RNA/química , RNA/metabolismo , Ligação de Hidrogênio , Estrutura Molecular , Conformação de Ácido Nucleico
11.
Chemistry ; 21(7): 2845-54, 2015 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-25537843

RESUMO

Photoregulation of RNA remains a challenging task as the introduction of a photoswitch entails changes in the shape and the stability of the duplex that strongly depend on the chosen linker strategy. Herein, the influence of a novel nucleosidic linker moiety on the photoregulation efficiency of azobenzene is investigated. To this purpose, two azobenzene C-nucleosides were stereoselectively synthesized, characterized, and incorporated into RNA oligonucleotides. Spectroscopic characterization revealed a reversible and fast switching process, even at 20 °C, and a high thermal stability of the respective cis isomers. The photoregulation efficiency of RNA duplexes upon trans-to-cis isomerization was investigated by using melting point studies and compared with the known D-threoninol-based azobenzene system, revealing a photoswitching amplitude of the new residues exceeding 90 % even at room temperature. Structural changes in the duplexes upon photoisomerization were investigated by using MM/MD calculations. The excellent photoswitching performance at room temperature and the high thermal stability make these new azobenzene residues promising candidates for in-vivo and nanoarchitecture photoregulation applications of RNA.


Assuntos
Compostos Azo/química , Nucleosídeos/química , RNA/química , Hibridização Genética , Estrutura Molecular , Oligonucleotídeos
12.
Biophys J ; 107(4): 932-40, 2014 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-25140428

RESUMO

Molecular photoswitches provide a promising way for selective regulation of nanoscaled biological systems. It has been shown that conformational changes of azobenzene, one of the widely used photoswitches, can be used to reversibly control DNA duplex formation. Here, we investigate the conformational response of DNA upon azobenzene binding and isomerization, using a threoninol linker that has been experimentally investigated recently. To this end, nonequilibrium molecular dynamics simulations are carried out using a switching potential describing the photoinduced isomerization. Attachment of azobenzene leads to a distortion of the DNA helical conformation that is similar for the trans and cis forms. However, the trans form is stabilized by favorable stacking interactions whereas the cis form is found to remain flipped out of the basepair-stacked position. Multiple azobenzene attachment augments the distortion in DNA helical conformation. The distorted DNA retains nativelike pairing of bases at ambient temperatures, but shows weaker basepairing compared to native DNA at an elevated temperature.


Assuntos
Compostos Azo/química , DNA de Forma B/química , Processos Fotoquímicos , Amino Álcoois/química , Butileno Glicóis/química , Isomerismo , Simulação de Dinâmica Molecular , Temperatura
13.
J Phys Chem B ; 118(29): 8478-88, 2014 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-24955654

RESUMO

As shown in recent experimental studies, photoswitches like azobenzene can act as efficient regulators of the folding and unfolding of DNA and RNA duplexes. Here we explore the details of the conformational changes induced by azobenzene attachment, focusing upon a small 14-mer RNA hairpin structure. The azobenzene chromophore is covalently bound to the stem region adjacent to a UUCG tetraloop which is known to represent a particularly stable structure. Since the characteristic time scale of conformational changes exceeds the nanosecond scale (and by far exceeds the ultrafast time scale of trans-to-cis photoswitching), equilibrium simulations using enhanced sampling by replica exchange molecular dynamics (REMD) are employed to investigate the influence of trans versus cis azobenzene attachment on the stability of the hairpin. We report on the analysis of fluctuations and conformational landscapes, along with calculations of relative melting temperatures. The simulations are found to reproduce certain experimentally predicted trends for azobenzene-modified RNA; in particular, both trans and cis conformers have a destabilizing effect. This effect is significantly enhanced for the cis conformer, even though the latter tends to flip out of the double-stranded stem region.


Assuntos
Compostos Azo/química , Compostos Azo/farmacologia , Sequências Repetidas Invertidas/efeitos dos fármacos , Simulação de Dinâmica Molecular , Estabilidade de RNA/efeitos dos fármacos , RNA/química , Pareamento de Bases , Sequência de Bases , Ligação de Hidrogênio , Conformação de Ácido Nucleico , Desnaturação de Ácido Nucleico , RNA/genética , Termodinâmica , Temperatura de Transição
14.
PLoS Comput Biol ; 7(12): e1002279, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22207822

RESUMO

Histone tails play an important role in nucleosome structure and dynamics. Here we investigate the effect of truncation of histone tails H3, H4, H2A and H2B on nucleosome structure with 100 ns all-atom molecular dynamics simulations. Tail domains of H3 and H2B show propensity of α-helics formation during the intact nucleosome simulation. On truncation of H4 or H2B tails no structural change occurs in histones. However, H3 or H2A tail truncation results in structural alterations in the histone core domain, and in both the cases the structural change occurs in the H2Aα3 domain. We also find that the contacts between the histone H2A C terminal docking domain and surrounding residues are destabilized upon H3 tail truncation. The relation between the present observations and corresponding experiments is discussed.


Assuntos
Histonas/química , Histonas/fisiologia , Nucleossomos/química , Nucleossomos/fisiologia , Histonas/ultraestrutura , Modelos Moleculares , Simulação de Dinâmica Molecular , Nucleossomos/ultraestrutura , Conformação Proteica , Relação Estrutura-Atividade
16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 82(4 Pt 1): 041910, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21230316

RESUMO

Weak bonds are ubiquitous in biological structures. They often act as adhesive contacts within an extended structure, for example, the internal bonds in a folded protein or a DNA/RNA loop. They also act as linkers between two structures, for example, a protein grafted in a cell membrane or a protein linking the cell membranes of two neighboring cells. Typically, the breakage of a bond depends on the strength of the binding potential and viscosity of the medium. But when extended structures couple to the bond, as in the above examples, the dynamics of the structure also has to be considered in order to understand the bond breakage phenomenon. Here we consider a generic model, a stretched polymer (an extended structure) tethered to a soft bond and study how the dynamics of the polymer, in addition to thermal noise, influences bond breakage. We also explore how the hydrodynamic interaction due to the fluid medium, which couples the distant parts of the polymer, change the bond breakage rate. We find that hydrodynamic interaction enhances the breakage rate and also makes the motion of the unstable collective mode of the polymer more coherent.

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