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1.
Proc Natl Acad Sci U S A ; 119(4)2022 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-35064080

RESUMO

The phase state of respiratory aerosols and droplets has been linked to the humidity-dependent survival of pathogens such as SARS-CoV-2. To inform strategies to mitigate the spread of infectious disease, it is thus necessary to understand the humidity-dependent phase changes associated with the particles in which pathogens are suspended. Here, we study phase changes of levitated aerosols and droplets composed of model respiratory compounds (salt and protein) and growth media (organic-inorganic mixtures commonly used in studies of pathogen survival) with decreasing relative humidity (RH). Efflorescence was suppressed in many particle compositions and thus unlikely to fully account for the humidity-dependent survival of viruses. Rather, we identify organic-based, semisolid phase states that form under equilibrium conditions at intermediate RH (45 to 80%). A higher-protein content causes particles to exist in a semisolid state under a wider range of RH conditions. Diffusion and, thus, disinfection kinetics are expected to be inhibited in these semisolid states. These observations suggest that organic-based, semisolid states are an important consideration to account for the recovery of virus viability at low RH observed in previous studies. We propose a mechanism in which the semisolid phase shields pathogens from inactivation by hindering the diffusion of solutes. This suggests that the exogenous lifetime of pathogens will depend, in part, on the organic composition of the carrier respiratory particle and thus its origin in the respiratory tract. Furthermore, this work highlights the importance of accounting for spatial heterogeneities and time-dependent changes in the properties of aerosols and droplets undergoing evaporation in studies of pathogen viability.


Assuntos
Cloreto de Cálcio/química , Modelos Químicos , Aerossóis e Gotículas Respiratórios/química , SARS-CoV-2/química , Albumina Sérica/química , Cloreto de Sódio/química , COVID-19/virologia , Difusão , Desinfecção/métodos , Humanos , Umidade , Cinética , Viabilidade Microbiana , Transição de Fase , Propriedades de Superfície
2.
Mol Pharm ; 21(5): 2484-2500, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38647432

RESUMO

Excipients are ubiquitous in pharmaceutical products, and often, they can also play a critical role in maintaining product quality. For a product containing a moisture-sensitive drug, moisture can be deleterious to the product stability during storage. Therefore, using excipients that interact with moisture in situ can potentially alleviate product stability issues. In this study, the interactive behavior of starch with moisture was augmented by coprocessing maize starch with sodium chloride (NaCl) or magnesium nitrate hexahydrate [Mg(NO3)2·6H2O] at different concentrations (5 and 10%, w/w). The effect of the formulation on drug stability was assessed through the degradation of acetylsalicylic acid, which was used as the model drug. The results showed that coprocessing of the starch with either NaCl or Mg(NO3)2·6H2O impacted the number of water molecule binding sites on the starch and how the sorbed moisture was distributed. The coprocessed excipients also resulted in lower drug degradation and lesser changes in tablet tensile strength during post-compaction storage. However, corresponding tablet formulations containing physical mixtures of starch and salts did not yield promising outcomes. This study demonstrated the advantageous concomitant use of common excipients by coprocessing to synergistically mitigate the adverse effects of moisture and promote product stability when formulating a moisture-sensitive drug. In addition, the findings could help to improve the understanding of moisture-excipient interactions and allow for the judicious choice of excipients when designing formulations containing moisture-sensitive drugs.


Assuntos
Estabilidade de Medicamentos , Excipientes , Amido , Comprimidos , Resistência à Tração , Excipientes/química , Amido/química , Comprimidos/química , Água/química , Química Farmacêutica/métodos , Cloreto de Sódio/química , Composição de Medicamentos/métodos , Aspirina/química
3.
Soft Matter ; 20(2): 330-337, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38087892

RESUMO

DNA functionalized pNipmam microgels, which have recently been introduced, are examined at different concentrations of sodium chloride and in PBS solutions via temperature dependent 1H-NMR measurements and are compared to pure pNipmam microgels. We show that the DNA modification shifts the volume phase transition temperature towards lower temperatures and the addition of salt and PBS further supports this effect in both materials. Thermodynamic values, i.e. enthalpy, entropy and Gibbs free energy, are determined via a non-linear fit which can be applied directly to the measurement data without further linearization.


Assuntos
Microgéis , Espectroscopia de Prótons por Ressonância Magnética , Temperatura , Termodinâmica , DNA , Cloreto de Sódio/química
4.
Analyst ; 149(11): 3186-3194, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38639484

RESUMO

The conformation of proteins is closely related to their biological functions, and it is affected by many factors, including the type of cations in solution. However, it is difficult to detect the conformational changes of a protein in situ. As a single-molecule sensing technology, nanopores can convert molecular structural information into analyzable current signals within a reasonable time range. Herein, we detect and analyze the effects of two different types of monovalent cations (Na+ and Li+) on a model protein bovine serum albumin (BSA) conformation using SiNx nanopores with different diameters. The quantitative analysis results show that the excluded volume of BSA in LiCl salt solutions is larger than the value in NaCl solution, indicating that Li+ is more prone to unfolding the proteins and making them unstable. This study demonstrated that nanopores enable the in situ detection of the structure of proteins at the single-molecule level and provide a new approach for the quantitative analysis of proteins.


Assuntos
Nanoporos , Soroalbumina Bovina , Soroalbumina Bovina/química , Bovinos , Estabilidade Proteica , Animais , Conformação Proteica , Cloreto de Lítio/química , Cloreto de Sódio/química , Compostos de Silício/química , Cátions/química
5.
Environ Sci Technol ; 58(21): 9091-9101, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38709279

RESUMO

People of all ages consume salt every day, but is it really just salt? Plastic nanoparticles [nanoplastics (NPs)] pose an increasing environmental threat and have begun to contaminate everyday salt in consumer goods. Herein, we developed a combined surface enhanced Raman scattering (SERS) and stimulated Raman scattering (SRS) approach that can realize the filtration, enrichment, and detection of NPs in commercial salt. The Au-loaded (50 nm) anodic alumina oxide substrate was used as the SERS substrate to explore the potential types of NP contaminants in salts. SRS was used to conduct imaging and quantify the presence of the NPs. SRS detection was successfully established through standard plastics, and NPs were identified through the match of the hydrocarbon group of the nanoparticles. Simultaneously, the NPs were quantified based on the high spatial resolution and rapid imaging of the SRS imaging platform. NPs in sea salts produced in Asia, Australasia, Europe, and the Atlantic were studied. We estimate that, depending on the location, an average person could be ingesting as many as 6 million NPs per year through the consumption of sea salt alone. The potential health hazards associated with NP ingestion should not be underestimated.


Assuntos
Análise Espectral Raman , Plásticos , Nanopartículas , Cloreto de Sódio/química
6.
Environ Sci Technol ; 58(20): 8610-8630, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38720447

RESUMO

Solar desalination, a green, low-cost, and sustainable technology, offers a promising way to get clean water from seawater without relying on electricity and complex infrastructures. However, the main challenge faced in solar desalination is salt accumulation, either on the surface of or inside the solar evaporator, which can impair solar-to-vapor efficiency and even lead to the failure of the evaporator itself. While many ideas have been tried to address this ″salt accumulation″, scientists have not had a clear system for understanding what works best for the enhancement of salt-rejecting ability. Therein, for the first time, we classified the state-of-the-art salt-rejecting designs into isolation strategy (isolating the solar evaporator from brine), dilution strategy (diluting the concentrated brine), and crystallization strategy (regulating the crystallization site into a tiny area). Through the specific equations presented, we have identified key parameters for each strategy and highlighted the corresponding improvements in the solar desalination performance. This Review provides a semiquantitative perspective on salt-rejecting designs and critical parameters for enhancing the salt-rejecting ability of dilution-based, isolation-based, and crystallization-based solar evaporators. Ultimately, this knowledge can help us create reliable solar desalination solutions to provide clean water from even the saltiest sources.


Assuntos
Água do Mar , Purificação da Água , Purificação da Água/métodos , Água do Mar/química , Luz Solar , Salinidade , Sais/química , Cloreto de Sódio/química
7.
Nature ; 553(7686): 68-72, 2018 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-29258293

RESUMO

Designing materials to function in harsh environments, such as conductive aqueous media, is a problem of broad interest to a range of technologies, including energy, ocean monitoring and biological applications. The main challenge is to retain the stability and morphology of the material as it interacts dynamically with the surrounding environment. Materials that respond to mild stimuli through collective phase transitions and amplify signals could open up new avenues for sensing. Here we present the discovery of an electric-field-driven, water-mediated reversible phase change in a perovskite-structured nickelate, SmNiO3. This prototypical strongly correlated quantum material is stable in salt water, does not corrode, and allows exchange of protons with the surrounding water at ambient temperature, with the concurrent modification in electrical resistance and optical properties being capable of multi-modal readout. Besides operating both as thermistors and pH sensors, devices made of this material can detect sub-volt electric potentials in salt water. We postulate that such devices could be used in oceanic environments for monitoring electrical signals from various maritime vessels and sea creatures.


Assuntos
Compostos de Cálcio/química , Eletricidade , Níquel/química , Compostos Organometálicos/química , Óxidos/química , Cloreto de Sódio/química , Titânio/química , Água/química , Organismos Aquáticos , Concentração de Íons de Hidrogênio , Transição de Fase , Prótons , Navios , Síncrotrons , Temperatura
8.
Environ Res ; 251(Pt 1): 118589, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38428560

RESUMO

The use of graphene sheets in water treatment is increasing due to its adsorption capacity, reactivity, catalytic action and surface area. The challenges linked to wastewater treatment are vast due to the constant influx of various pollutants. Can the challenges of water desalination and purification be encountered by graphene-based composites and membranes?.The current work describes the synthesis of graphene oxide (GO) using modified Hummers' method. GO was functionalized with chitosan and used as adsorbents. On the other hand, it was reported that the surface of thin-film-composite (TFC) polyamide membranes was modified in order to desalinate highly saline water using pervaporation. The findings showed that GO synthesized by modified Hummers' method has a greater capacity for the adsorption of sodium ion and have better regeneration performance. Functionalization with chitosan increased adsorption capacity from 680.2 to 740.5 mg/g at the initial concentration of 45,000 mg/l of Na+ ions. On the other hand, modification in membrane comprises the chlorine treatment of surface of polyamide membrane. Layer-by-layer (LbL) deposition of positively charged polyethyleneimine (PEI) and negatively charged graphene oxide (GO) was followed. The PEI/GO LbL membrane's pure water flux was twice as high as compare to the original membrane. The synthesized membrane was tested against the aqueous solutions containing Na2SO4, MgSO4, NaCl and MgCl2 salts for their desalination. At different concentrations, a water flux of 8.9 kg/m2h with a huge salt rejection (>99.9%) was attained for every tested salt. It was observed that CS functionalized GO and GO membrane showed higher adsorption capacity and improved regeneration performance can be measured as an operational and active adsorbent for sea water desalination.


Assuntos
Quitosana , Grafite , Membranas Artificiais , Purificação da Água , Grafite/química , Quitosana/química , Purificação da Água/métodos , Adsorção , Salinidade , Cloreto de Sódio/química
9.
J Oncol Pharm Pract ; 30(1): 142-150, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37078110

RESUMO

INTRODUCTION: This study aimed to determine the stability of cetuximab: (1) under "in-use" conditions after dilution to 1 mg/mL in 0.9% sodium chloride in polyolefin bags and (2) as an undiluted solution (5 mg/mL) repackaged in polypropylene bags or kept in the vial after opening. METHODS: Ready-to-use 500 mg/100 mL vials of cetuximab solution were diluted to 1 mg/mL in 100 mL bags of 0.9% sodium chloride or repackaged as a 5 mg/mL solution into empty 100 mL bags. Bags and vials were stored at 4°C for 90 days and 25°C for 3 days. A syringe sample of 7 mL was taken from each bag for the initial determinations. The sampled bags were weighed to determine their initial weight and placed under the planned storage conditions. The physicochemical stability of cetuximab was estimated using validated methods. RESULTS: No changes in turbidity, no protein loss, and no changes in cetuximab tertiary structure were observed after 30 days of storage or when subjected to a temperature excursion of 3 days at 25°C and when stored at 4°C for up to 90 days, regardless of the concentrations and batches. The colligative parameters did not change under any of the tested conditions. No evidence of microbial growth was found in bags after 90 days of storage at 4°C. CONCLUSION: These results support the extended in-use shelf-life of cetuximab vials and bags, which can be cost-effective for healthcare providers.


Assuntos
Embalagem de Medicamentos , Cloreto de Sódio , Humanos , Cetuximab , Cloreto de Sódio/química , Infusões Parenterais , Temperatura , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Cromatografia Líquida de Alta Pressão
10.
Int J Phytoremediation ; 26(1): 114-130, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37405369

RESUMO

This study illustrates the salinity tolerance mechanisms in Volkameria inermis (a mangrove-associate), making it an ideal candidate for establishment in saline lands. The plant was exposed to 100, 200, 300, and 400 mM NaCl and the TI value indicates that the stress-imparting concentration was 400 mM. There was a decrease in biomass and tissue water, and a gradual increase in osmolytes like soluble sugars, proline, and free amino acids content was observed in plantlets with the increase in NaCl concentrations. Higher number of lignified cells in the vascular region of the plantlet's leaves treated with NaCl (400 mM) may influence the transport through the conducting tissues. SEM data reveals the presence of thick-walled xylem elements, an increased number of trichomes, and partially/fully closed stomata in the 400 mM NaCl-treated samples of V. inermis. In general, macro and micronutrient distribution tend to be affected in the NaCl-treated plantlets. However, Na content increased remarkably in plantlets treated with NaCl, and the highest accumulation was observed in roots (5.58-fold). Volkameria inermis can be a good option for phytodesalination in salt-affected areas since it is equipped with strong NaCl tolerance strategies and can be exploited for desalinization purpose of salt affected lands.


The phytodesalination potential of V. inermis was proved with the aid of physiochemical and anatomical studies, which was not yet revealed. The present study elucidated the level of NaCl tolerance in V. inermis and the development of associated adaptive responses.


Assuntos
Folhas de Planta , Cloreto de Sódio , Cloreto de Sódio/química , Cloreto de Sódio/metabolismo , Biodegradação Ambiental , Folhas de Planta/metabolismo , Salinidade
11.
Int J Mol Sci ; 25(12)2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38928132

RESUMO

Ruthenium chloride (RuCl3) is widely utilized for synthesis and catalysis of numerous compounds in academia and industry and is utilized as a key molecule in a variety of compounds with medical applications. Interestingly, RuCl3 has been demonstrated to modulate human plasmatic coagulation and serves as a constituent of a compounded inorganic antivenom that neutralizes the coagulopathic effects of snake venom in vitro and in vivo. Using thrombelastography, this investigation sought to determine if RuCl3 inhibition of the fibrinogenolytic effects of Crotalus atrox venom could be modulated by vehicle composition in human plasma. Venom was exposed to RuCl3 in 0.9% NaCl, phosphate-buffered saline (PBS), or 0.9% NaCl containing 1% dimethyl sulfoxide (DMSO). RuCl3 inhibited venom-mediated delay in the onset of thrombus formation, decreased clot growth velocity, and decreased clot strength. PBS and DMSO enhanced the effects of RuCl3. It is concluded that while a Ru-based cation is responsible for significant inhibition of venom activity, a combination of Ru-based ions containing phosphate and DMSO enhances RuCl3-mediated venom inhibition. Additional investigation is indicated to determine what specific Ru-containing molecules cause venom inhibition and what other combinations of inorganic/organic compounds may enhance the antivenom effects of RuCl3.


Assuntos
Antivenenos , Coagulação Sanguínea , Venenos de Crotalídeos , Crotalus , Dimetil Sulfóxido , Humanos , Dimetil Sulfóxido/farmacologia , Dimetil Sulfóxido/química , Antivenenos/farmacologia , Antivenenos/química , Venenos de Crotalídeos/antagonistas & inibidores , Venenos de Crotalídeos/farmacologia , Animais , Coagulação Sanguínea/efeitos dos fármacos , Compostos de Rutênio/farmacologia , Compostos de Rutênio/química , Cloreto de Sódio/farmacologia , Cloreto de Sódio/química , Tromboelastografia , Serpentes Peçonhentas
12.
J Sci Food Agric ; 104(10): 6070-6084, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38441435

RESUMO

BACKGROUND: Salted hen egg yolks are less oily and less flavorful than salted duck egg yolks. However, hen eggs have a more adequate market supply and have a broader application prospect than duck eggs. In the present study, egg yolks, plasma, and granules were dehydrated by adding 1% NaCl to simulate traditional curing process of salted egg yolk. The changes in the pickling process of hen egg yolks (HEY) and duck egg yolks (DEY) plasma and granules were compared to reveal the gelation mechanism and the underlying causes of quality differences in salted HEY and DEY. Salted HEY can be compared with the changes in DEY during the pickling process to provide a theoretical basis for the quality improvement of salted HEY to salted DEY. RESULTS: The results showed that both plasma and granules were involved in gel formation, but exhibited different aggregation behaviors. Based on the intermolecular forces, the HEY proteins achieved aggregation mainly through hydrophobic interactions and DEY proteins mainly through covalent binding. According to spin-spin relaxation time, HEY gels immobilized a large amount of lipid and interacted strongly with lipids. DEY gels showed much free lipid and had weak interaction with lipid. The microstructure showed that HEY proteins were easily unfolded to form a homogeneous three-dimensional gel network structure after salting, whereas heterogeneous aggregates were formed to hinder the gel development in DEY. Changes in protein secondary structure content showed that pickling can promote the transformation of the α-helices to ß-sheets structure in HEY gels, whereas more α-helices structure was formed in DEY gels. CONCLUSION: The present study has demonstrated that different gelation behaviors of hen and duck egg yolk proteins (especially in plasma) through salting treatment led to the difference in the quality of salted HEY and DEY. © 2024 Society of Chemical Industry.


Assuntos
Galinhas , Patos , Gema de Ovo , Manipulação de Alimentos , Géis , Cloreto de Sódio , Animais , Gema de Ovo/química , Géis/química , Cloreto de Sódio/química , Manipulação de Alimentos/métodos , Proteínas do Ovo/química , Dessecação/métodos , Interações Hidrofóbicas e Hidrofílicas
13.
J Sci Food Agric ; 104(10): 6108-6117, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38445510

RESUMO

BACKGROUND: Excessive NaCl intake in liquid and semi-solid food (e.g. soup, hot pot base, sauce) poses a high risk to human health, and reducing NaCl intake is a major concern for global health. RESULTS: Using the generalized Labeled Magnitude Scale (gLMS) method, the study verified the possibility of sodium reduction through oil addition. The compromised acceptance threshold (CAT) and hedonic rejection threshold (HRT) were determined. The gLMS results showed that the saltiness intensity of samples containing 0.36% NaCl and 2.29% sunflower seed oil was significantly higher than that of samples containing only 0.36% NaCl (P < 0.05). CAT and HRT results indicated that by adding 3.59% sunflower oil, the NaCl content could be reduced to a minimum of 0.14% without causing sensory rejection in bone broth samples. The quantitative descriptive analysis method was used to determine the effects of NaCl and oil concentrations on the sensory attributes of bone broth samples. Furthermore, it was used to analyze the consumer acceptability drivers in combination with the hedonic scale to optimize the formulation of reduced-salt bone broth products. Notably, sample E (0.36% NaCl, 2.29% fat) not only had a significant salt reduction effect with a 20% decrease in NaCl, but also had improved overall acceptability. CONCLUSION: This study provides theoretical guidance for designing salt-reduction cuisine within the catering and food industries, including bone broth and hot pot bases. © 2024 Society of Chemical Industry.


Assuntos
Comportamento do Consumidor , Paladar , Humanos , Adulto , Óleo de Girassol/química , Feminino , Masculino , Aditivos Alimentares/análise , Aditivos Alimentares/química , Cloreto de Sódio/análise , Cloreto de Sódio/química , Adulto Jovem , Pessoa de Meia-Idade , Cloreto de Sódio na Dieta/análise , Osso e Ossos/química
14.
J Sci Food Agric ; 104(10): 6242-6251, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38456730

RESUMO

BACKGROUND: The pickling process with NaCl is an essential step for pork preservation. This study aimed to investigate the effect of different ultrasonic intensities of tri-frequency simultaneous ultrasound (TSIU) pickling on the NaCl content and quality of pork (longissimus dorsi). After 30 min pickling, the NaCl content, moisture content, pickling yield, cooking loss, textural properties, color, pH, moisture migration and distribution as well as microstructure of pork were assessed. RESULTS: Results showed that among all the ultrasonic treatment intensities (85-150 W L-1), the NaCl content of the sample pickled by an intensity of 101.3 W L-1 was higher than that of other intensities. TSIU 101.3 W L-1 showed 59.95% higher NaCl content than the control sample. In addition, the sample treated with TSIU of 101.3 W L-1 had higher pickling yield and moisture content, better textural properties of pork (including hardness and chewiness), and less cooking loss. The results of the low-field nuclear magnetic resonance showed that, compared with the control group, the relaxation time T21 of the ultrasound-assisted pickling samples increased, while the proportion of T22 (A22) reduction ranged from 175.0% to 379.9%. The microstructure designated that the ultrasonic treatment could facilitate changes in meat texture. CONCLUSION: Ultrasound marination of different intensities promoted the diffusion of NaCl and affected the quality of pork tenderloins. The TSIU at 101.3 W L-1 could better accelerate NaCl transport and homogeneous distribution on meat, thereby improving the sample quality. © 2024 Society of Chemical Industry.


Assuntos
Culinária , Manipulação de Alimentos , Cloreto de Sódio , Animais , Cloreto de Sódio/química , Cloreto de Sódio/análise , Suínos , Manipulação de Alimentos/métodos , Culinária/métodos , Melhoria de Qualidade , Ultrassom/métodos , Produtos da Carne/análise , Conservação de Alimentos/métodos , Cor , Músculo Esquelético/química , Músculo Esquelético/efeitos da radiação
15.
Water Sci Technol ; 89(9): 2209-2224, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38747945

RESUMO

The research presented in this paper is to determine the best tracer studies that will give acceptable estimates of longitudinal dispersion coefficient for Orashi river using rhodamine WT dye and sodium chloride as water tracer. Estimated results obtained for longitudinal dispersion coefficient for the case of rhodamine WT experiment ranges between 71 and 104.4 m2s-1 while that of sodium chloride experiment ranges between 20.1 and 34.71 m2s-1. These results revealed lower dispersion coefficient using sodium chloride as water tracer (WT) indicating that for larger rivers, sodium chloride should not be used as water tracer. The usage of sodium chloride as water tracer in the estimation of longitudinal dispersion coefficient is recommended in smaller streams as NaCl is relatively conservative. The established equations for both cases of investigation are proving satisfactory upon validation as degree of accuracy of 100.0% was obtained using discrepancy ratio (Dr). Standard error (SE), normal mean error (NME) and mean multiplication error (MME) of the developed equations is better when compared with other existing equations. However, Equation (17) is satisfactorily recommended.


Assuntos
Cloreto de Sódio , Cloreto de Sódio/química , Movimentos da Água , Rodaminas/química , Rios/química , Poluentes Químicos da Água/análise
16.
Polim Med ; 54(1): 45-57, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38315071

RESUMO

BACKGROUND: One of the important formalisms of non-equilibrium thermodynamics is Peusner network thermodynamics. The description of the energy conversion in membrane processes, i.e., the conversion of the internal energy of the system into the dissipated energy and the free energy used for the work associated with the transport of solution components, allows us to describe the relationship between these energies and the thermodynamic forces acting in the membrane system. OBJECTIVES: The aim of this study was to develop a procedure to transform the Kedem-Katchalsky equations for the transport of binary electrolytic solutions across a membrane into the Kedem-Katchalsky-Peusner equations based on Peusner network thermodynamics. The conversion of electrochemical energy to free energy in the membrane system was also determined. MATERIAL AND METHODS: The nanobiocellulose biomembranes (Biofill) were the subject of the study with experimentally determined transport parameters for aqueous NaCl solutions. The research method is the Kedem-Katchalsky-Peusner formalism for binary electrolyte solutions with introduced Peusner coefficients. RESULTS: The coefficients of the L version of the membrane transport equations and the Peusner coupling coefficients were derived as functions of NaCl concentration in the membrane. Based on these coefficients, the fluxes of internal energy of the system, energy dissipated to the surroundings and free energy related to the transport of electrolyte across the membrane were calculated and presented as functions of the osmotic and electric forces on the membrane. CONCLUSIONS: The Peusner coefficients obtained from the transformations of the coefficients of the Kedem-Katchalsky formalism for the transport of electrolyte solutions through the Biofill membrane were used to calculate the coupling coefficients of the membrane processes and the dissipative energy flux. The dissipative energy flux takes the form of a quadratic form due to the thermodynamic forces on the membrane - second degree curves are obtained. Moreover, the dissipative energy flux as a function of thermodynamic forces allowed us to examine the energy conversion in transport processes in the membrane system.


Assuntos
Eletrólitos , Membranas Artificiais , Termodinâmica , Eletrólitos/química , Soluções/química , Modelos Químicos , Cloreto de Sódio/química
17.
Protein Expr Purif ; 203: 106217, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36529448

RESUMO

For recombinantly produced monoclonal antibody (mAb), charge variants including acidic and basic species are common heterogeneities. For characterization purpose, sufficient amount of acidic and basic species with high purity is needed. In this work, we developed an approach that allows for continuous separating and collecting of acidic and basic charge variants. First, with batch-mode cation exchange (CEX) chromatography, the load density and linear salt gradient elution conditions under which good separation of both charge variants can be achieved were determined. Next, a stepwise elution protocol was developed based on the linear gradient elution. Finally, acidic and basic charge variants were persistently produced under stepwise elution using a customized twin-column continuous chromatography system. This approach allows acidic and basic charge variants with high purity (i.e., >90%) to be efficiently generated in sufficient amount, which greatly facilitates the necessary characterization of these mAb variants.


Assuntos
Anticorpos Monoclonais , Cloreto de Sódio , Cromatografia por Troca Iônica/métodos , Cloreto de Sódio/química , Anticorpos Monoclonais/química , Cátions/química
18.
Biomacromolecules ; 24(3): 1194-1208, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36779888

RESUMO

In this study, complex coacervates of the biopolyelectrolytes chitosan and gum arabic were investigated with respect to their composition and charge compensation depending on the pH and salt concentration. Individual polyelectrolyte yields were deduced from thermogravimetric analysis and chitosan quantification via enzymatic hydrolysis/HPLC-ELSD. The polyelectrolyte mass ratio in the complex coacervate is found to remain approximately constant irrespective of the pH, despite the latter's effect on the polyelectrolyte charge ratio. Two regimes are identified, including either chitosan charges in excess (at pH < 6.0) or gum arabic charges in excess (at pH > 6.0). The amount of extrinsic charge compensation in the complex coacervates is discussed in detail. We show for the first time that the doping level, a quantity traditionally used to describe salt-induced changes of the charge compensation in polyelectrolyte complexes, is also suitable for the description of pH-induced extrinsic charge compensation in such systems.


Assuntos
Quitosana , Quitosana/química , Goma Arábica/química , Polieletrólitos , Cloreto de Sódio/química , Concentração de Íons de Hidrogênio
19.
Biomacromolecules ; 24(2): 775-788, 2023 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-36546647

RESUMO

Engineering the rheological properties of colloidal inks is one of the main challenges in achieving high-fidelity 3D printing. Herein, we provide a comprehensive study on the rheological behavior of inks based on cellulose nanocrystals (CNCs) in the presence of given salts to enable high-quality 3D printing. The rheological properties of the CNC suspensions are tailored by considering the nature of the electrolyte (i.e., 10 types of salts featuring different ion sizes, charge numbers, and inter- and intra-molecular interactions) at various concentrations (25-100 mM). A high printing fidelity is achieved in a narrow CNC and salt concentration range, significantly depending on the salt type. The structure-property relationship is explored in a "3D-printing" space (2D map), introducing a guideline for researchers active in this field. To further unravel the effect of salt type on morphological properties, CNC aerogels are developed by freeze-drying the printed structures. The results illustrate that enhancing viscoelastic properties render a denser structure featuring smaller pores.


Assuntos
Celulose , Nanopartículas , Celulose/química , Tinta , Sais , Impressão Tridimensional , Cloreto de Sódio/química , Nanopartículas/química
20.
Extremophiles ; 27(2): 20, 2023 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-37481762

RESUMO

A significant portion of the earth has a salty environment, and the literature on bacterial survival mechanisms in salty environments is limited. During molecular evolution, halophiles increase acidic amino acid residues on their protein surfaces which leads to a negatively charged surface potential that helps them to maintain the protein integrity and protect them from denaturation by competing with salt ions. Through protein family analysis, we have investigated the molecular-level adaptive features of DNA polymerase III's catalytic subunit (alpha) and its structure-function relationship. This study throws light on the novel understanding of halophilic bacterial replication and the molecular basis of salt adaptation. Comparisons of the amino acid contents and electronegativity of halophilic and mesophilic bacterial proteins revealed adaptations that allow halophilic bacteria to thrive in high salt concentrations. A significantly lower isoelectric point of halophilic bacterial proteins indicates the acidic nature. Also, an abundance of disordered regions in halophiles suggests the requirement of the salt ions that play a crucial role in their stable protein folding. Despite having similar topology, mesophilic and halophilic proteins, a set of very prominent molecular modifications was observed in the alpha subunit of halophiles.


Assuntos
DNA Polimerase III , Cloreto de Sódio , Cloreto de Sódio/química , Cloreto de Sódio/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Evolução Molecular , Íons
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