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1.
J Chem Phys ; 158(2): 024904, 2023 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-36641409

RESUMO

The interplay of liquid-liquid phase separation (LLPS) and dynamical arrest can lead to the formation of gels and glasses, which is relevant for such diverse fields as condensed matter physics, materials science, food engineering, and the pharmaceutical industry. In this context, protein solutions exhibit remarkable equilibrium and non-equilibrium behaviors. In the regime where attractive and repulsive forces compete, it has been demonstrated, for example, that the location of the dynamical arrest line seems to be independent of ionic strength, so that the arrest lines at different ionic screening lengths overlap, in contrast to the LLPS coexistence curves, which strongly depend on the salt concentration. In this work, we show that the same phenomenology can also be observed when the electrostatic repulsions are largely screened, and the range and strength of the attractions are varied. In particular, using lysozyme in brine as a model system, the metastable gas-liquid binodal and the dynamical arrest line as well as the second virial coefficient have been determined for various solution conditions by cloud-point measurements, optical microscopy, centrifugation experiments, and light scattering. With the aim of understanding this new experimental phenomenology, we apply the non-equilibrium self-consistent generalized Langevin equation theory to a simple model system with only excluded volume plus short-range attractions, to study the dependence of the predicted arrest lines on the range of the attractive interaction. The theoretical predictions find a good qualitative agreement with experiments when the range of the attraction is not too small compared with the size of the protein.


Assuntos
Modelos Biológicos , Proteínas , Géis , Concentração Osmolar , Eletricidade Estática , Soluções
2.
Sci Rep ; 13(1): 409, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624299

RESUMO

Solanum nigrum L. (Black nightshade), is one of the most troublesome weeds of summer crops such as corn, soybean, sunflower, etc. To study the effect of combined Castor oil as an adjuvant with different doses of Lumax (Mesotrion + S-metolacholor + Terbuthylazine) on the physiological behavior of Solanum nigrum L., a greenhouse experiment was conducted in randomized complete block design with four replications in agricultural faculty of the University of Tabriz in 2021. A foliar application of Lumax increased proline, malondialdehyde, and hydrogen peroxide concentrations and superoxide dismutase, catalase, and peroxidase activity. The content of protein and photosynthetic pigments (Chlorophyll a, b, and carotenoids) also decreased significantly by using Lumax herbicide. Applying castor oil in combination with Lumax intensifies oxidative stress and lipid peroxidation. Results showed that by increasing the herbicide doses in comparison with control (non-herbicide), Area, Fm, Fv, Fv/Fm, Fv/F0, Sm, Sm/Tfm, and Fv/F0 decreased 48.32%, 19.52%, 27.95%, 10.47%, 50.90%, 28.34%, 79.38%, and 50.90%, respectively and F0, F0/Fm increased 46.76% and 82.38%, respectively. Castor oil showed a synergistic effect on Lumax herbicide and enhanced its efficacy on Solanum nigrum. The presented results supported the view that by evaluating chlorophyll a fluorescence parameters, we would realize herbicide (alone or mixed with any adjacent) efficacy before the visual symptoms appear in the plant.


Assuntos
Óleo de Rícino , Herbicidas , Solanum nigrum , Antioxidantes/metabolismo , Óleo de Rícino/farmacologia , Clorofila A/metabolismo , Fluorescência , Fotossíntese , Solanum nigrum/efeitos dos fármacos , Solanum nigrum/metabolismo , Concentração Osmolar , Herbicidas/farmacologia , Combinação de Medicamentos
3.
Invest Ophthalmol Vis Sci ; 64(1): 5, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36626176

RESUMO

Purpose: To determine the relationships of (1) tear osmolarity (TO) levels with the severity of signs and symptoms of dry eye disease (DED) and (2) changes in TO with changes in signs and symptoms. Methods: Patients (N = 405) with moderate to severe DED in the Dry Eye Assessment and Management (DREAM) Study were evaluated at baseline and at six and 12 months. Associations of TO with signs and symptoms were evaluated using Pearson correlation coefficient (r) and regression models. Results: The mean (standard deviation [SD]) TO was 303 (16) mOsm/L at baseline and 303 (18) mOsm/L at both six and 12 months. TO was higher in older patients (306 mOsm/L for ≥70 years vs. 300 mOsm/L for <50 years; P = 0.01) and those with Sjögren's disease (311 vs. 302 mOsm/L; P < 0.0001). TO did not differ between patients randomized to placebo and omega-3 fatty acid supplementation. TO was weakly correlated with conjunctival (r = 0.18; P < 0.001) and corneal staining scores (r = 0.17; P < 0.001), tear film break-up time (r = 0.06; P = 0.03), and Schirmer test score (r = -0.07; P = 0.02) but not with Ocular Surface Disease Index scores (r = 0.03; P = 0.40). Changes in signs and were not significantly correlated with change in TO at six or 12 months. Conclusions: Within DREAM, TO was weakly correlated with DED signs, explaining <5% variability in signs. Changes in tear osmolarity were not associated with changes in signs and symptoms of DED, indicating that the association may not be causal.


Assuntos
Síndromes do Olho Seco , Síndrome de Sjogren , Humanos , Idoso , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/tratamento farmacológico , Lágrimas , Síndrome de Sjogren/diagnóstico , Túnica Conjuntiva , Concentração Osmolar
4.
Am J Emerg Med ; 63: 127-131, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36371934

RESUMO

BACKGROUND: Administration of 3% sodium chloride through a peripheral venous catheter is associated with risk of infusion-related adverse events (IRAE) due to its high osmolarity. Given this concern and the paucity of data regarding these events, many hospitals have policies that require central line administration of 3% sodium chloride. OBJECTIVE: The objective of this analysis was to evaluate the incidence of IRAE associated with peripheral administration of 3% sodium chloride. METHODS: This analysis included patients who received 3% sodium chloride via a peripheral venous catheter between May 2017 and August 2019. The major endpoint of this analysis was the overall incidence of IRAE, defined as the documentation of infiltration or phlebitis. A multivariable logistic regression was performed to identify potential risk factors (e.g., age, infusion rate, infusion duration, peripheral venous catheter location, and needle gauge) for development of IRAE. RESULTS: A total of 706 administrations in 422 patients were included. Seventy-four (10.5%) administrations were associated with a documented event. Based on the Infusion Nurses grading scale for infiltration or phlebitis, 48% of the events in this analysis were grade 1 in severity. Duration of infusion of 3% sodium chloride was found to be associated with an increased odds of an IRAE (OR per 1 h 1.02, 95% CI 1.01-1.02) in the multivariable analysis. Age, infusion rate, peripheral venous catheter location, and needle gauge were not independently associated with an increased risk of an IRAE. CONCLUSION: These data suggest that IRAE occurred more frequently when 3% sodium chloride was administered over a longer duration and the majority of events were mild with no permanent tissue injury. It may be reasonable to consider peripheral administration of 3% sodium chloride in the acute care setting for a short duration, although additional studies are needed to continue to evaluate its safety.


Assuntos
Cateterismo Periférico , Solução Salina , Humanos , Cloreto de Sódio , Concentração Osmolar , Solução Salina/administração & dosagem , Solução Salina/efeitos adversos , Cateterismo Periférico/efeitos adversos
5.
J Environ Manage ; 328: 116971, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36516708

RESUMO

For the in-situ remediation of the contaminated subsurface environment, the injection of nutrients and microorganisms changes chemical and physical conditions, which control the delivery and immobilization of microorganisms. We investigated the injection strategy for effective bacterial delivery in a bioaugmentation scheme by controlling ionic strength (IS) and pore-water velocity (v). A set of bacterial transport tests was conducted using the saturated sand column to mimic the saturated subsurface environment. The effectiveness of the injection strategies was evaluated by applying solutions with different ionic strengths into the sand column with different pore-water velocities. The deposition and delivery of bacteria through the sand column were analyzed using the first-order deposition model. The deposition and delivery of bacteria injected by various strategies were numerically simulated considering the variable deposition rate. The breakthrough curves from column experiments revealed that the bacterial deposition on the sand surface was increased by an increase in the ionic strength and by a decrease in the pore-water velocities. The rates of bacterial deposition (k1) on sand could be determined as a function of ionic strength and pore-water velocity, and it was applicable to simulate the delivery of bacteria under dynamic groundwater conditions. The numerical case study considering various injection strategies showed that the nutrient concentration controlled the bacterial delivery to the target area more significantly than the injection flow rate. Injection of bacterial solution with lower nutrient concentration could be increased the deposited bacterial concentration at the target point (Stp) by 6.2-7.1 times higher. Short pulse injection with a high injection rate decreased Stp by 67-78%. The efficiency of bacterial delivery (Ed) could be increased three times higher by lowering nutrient concentration in the injection solution. The process of evaluating the efficiency of bacterial delivery could be a prominent approach to determining the injection strategy for in-situ remediation considering variable conditions of a contaminated site.


Assuntos
Areia , Água , Água/química , Concentração Osmolar , Porosidade , Dióxido de Silício
6.
Adv Clin Exp Med ; 31(12): 1413-1418, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36482816

RESUMO

BACKGROUND: Osmolarity is used to detect symptoms of dry eye disease (DED) and can be measured using TearLab™ and I-Pen® systems. OBJECTIVES: To investigate the correlation between osmolarity measurements using the TearLab™ and I-Pen® systems in subjects with a high body mass index (BMI). MATERIAL AND METHODS: Thirty male subjects with a high BMI (27-48 kg/m2; 23.3 ±2.1 years old) participated in this study. The control group consisting of 30 healthy males (24.9 kg/m2; 22.9 ±2.1 years old) was also enrolled. Osmolarity measurements were recorded from the right eye using the TearLab™ and I-Pen® systems, and interviews were conducted to determine ocular surface disease index (OSDI) scores. RESULTS: The OSDI (p = 0.042), TearLab™ (p < 0.001) and I-Pen® (p < 0.001) scores were significantly higher in the study group than in the control group. In the study group, OSDI scores ranged from 2 to 16 (median 8.0, interquartile range (IQR) 6.8), while it was from 0 to 10 (median 6.3, IQR 4.1) in the control group. The TearLab™ osmolarity scores were in the range of 278-309 mOsm/L in the study group, whereas the I-Pen® osmolarity measurements were in the range of 294-336 mOsm/L in the study group, compared with 263-304 mOsm/L and 278-317 mOsm/L in the control group, respectively. In the study group, there was a strong correlation between the TearLab™ and I-Pen® osmolarity scores (r = 0.934; p = 0.001). In addition, strong correlations were found between the BMI and both TearLab™ (r = 0.736; p = 0.001) and I-Pen® (r = 0.707; p = 0.001) scores, as well as between the OSDI scores and both TearLab™ (r = 0.731; p = 0.001) and I-Pen® measurements (r = 0.666; p = 0.001). CONCLUSION: Osmolarity measurements using the I-Pen® system were significantly higher than those recorded using the TearLab™ system in subjects with a high BMI. The I-Pen® measurements showed large variations in osmolarity scores and were highly unreliable in correctly identifying normal eyes compared to the TearLab™ system. Also, a strong correlation was found between the osmolarity scores obtained from the TearLab™ and I-Pen® systems.


Assuntos
Síndromes do Olho Seco , Lágrimas , Humanos , Masculino , Adulto Jovem , Adulto , Índice de Massa Corporal , Concentração Osmolar
7.
Molecules ; 27(23)2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36500320

RESUMO

This study investigated the effect of ultrasound on gel properties of soy protein isolates (SPIs) at different salt concentrations. The results showed that ultrasound could significantly improve the gel hardness and the water holding capacity (WHC) of the salt-containing gel (p < 0.05). The gel presents a uniform and compact three-dimensional network structure. The combination of 200 mM NaCl with 20 min of ultrasound could significantly increase the gel hardness (four times) and the WHC (p < 0.05) compared with the SPI gel without treatment. With the increase in NaCl concentration, the ζ potential and surface hydrophobicity increased, and the solubility decreased. Ultrasound could improve the protein solubility, compensate for the loss of solubility caused by the addition of NaCl, and further increase the surface hydrophobicity. Ultrasound combined with NaCl allowed proteins to form aggregates of different sizes. In addition, the combined treatment increased the hydrophobic interactions and disulfide bond interactions in the gel. Overall, ultrasound could improve the thermal gel properties of SPI gels with salt addition.


Assuntos
Temperatura Alta , Proteínas de Soja , Proteínas de Soja/química , Géis/química , Concentração Osmolar , Interações Hidrofóbicas e Hidrofílicas , Água/química , Cloreto de Sódio
8.
Sci Rep ; 12(1): 22304, 2022 12 24.
Artigo em Inglês | MEDLINE | ID: mdl-36566279

RESUMO

The cosmopolitan littoral earthworm Pontodrilus litoralis is distributed in tropical and sub-tropical coastal habitats, whereas P. longissimus is reported only in the Thai-Malay coastal line. In the present study, we examined the difference in salinity effect on the survival rate, wet weight (hereafter weight) change, behaviour, and osmolality of these two Pontodrilus species. A 28 d exposure to varying salinity concentration (0-50 ppt) revealed that P. litoralis is able to survive over a wide salinity range than P. longissimus, with the latter species exhibiting a low survival rate over the same salinity range. During short-term exposure (0-96 h) to a salinity of less than 30 ppt, P. litoralis exhibited weight gain and this was significant in the first 12 h of exposure. However, P. longissimus gained weight when exposed to salinity at under 10 ppt in the first 72 h of exposure. The two species of Pontodrilus behaved differently when exposed to different salinities. The coelomic fluid osmolarity of Pontodrilus was related to the exposure medium and was mostly maintained as hyperosmotic to the external medium over the range of salinities tested. This study shows how two different species of the littoral earthworm genus Pontodrilus respond to a change in salinity, which may explain their dispersal pattern and shape their distribution pattern throughout Southeast Asia.


Assuntos
Oligoquetos , Salinidade , Animais , Concentração Osmolar , Tailândia
9.
PLoS One ; 17(12): e0279372, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36525423

RESUMO

Salmonella enterica serovars Typhimurium and Typhi are enteropathogens that differ in host range and the diseases that they cause. We found that exposure to a combination of hypotonicity and the detergent Triton X-100 significantly reduced the viability of the S. Typhi strain Ty2 but had no effect on the S. Typhimurium strain SL1344. Further analysis revealed that hypotonicity was the critical factor: incubation in distilled water alone was sufficient to kill Ty2, while the addition of sodium chloride inhibited killing in a dose-dependent manner. Ty2's loss of viability in water was modified by culture conditions: bacteria grown in well-aerated shaking cultures were more susceptible than bacteria grown under less aerated static conditions. Ty2, like many S. Typhi clinical isolates, has an inactivating mutation in the rpoS gene, a transcriptional regulator of stress responses, whereas most S. Typhimurium strains, including SL1344, have the wild-type gene. Transformation of Ty2 with a plasmid expressing wild-type rpoS, but not the empty vector, significantly increased survival in distilled water. Moreover, an S. Typhi strain with wild-type rpoS had unimpaired survival in water. Inactivation of the wild-type gene in this strain significantly reduced survival, while replacement with an arabinose-inducible allele of rpoS restored viability in water under inducing conditions. Our observations on rpoS-dependent differences in susceptibility to hypotonic conditions may be relevant to the ability of S. Typhi and S. Typhimurium to tolerate the various environments they encounter during the infectious cycle. They also have implications for the handling of these organisms during experimental manipulations.


Assuntos
Salmonella typhi , Fator sigma , Salmonella typhi/genética , Fator sigma/genética , Proteínas de Bactérias/genética , Salmonella typhimurium , Concentração Osmolar , Água
10.
Clin Nutr ESPEN ; 52: 94-99, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36513491

RESUMO

BACKGROUND & AIMS: Preoperative dehydration is a well-known predictor of in-hospital complications and poor functional outcomes in older patients with hip fractures. In an orthopedic and geriatric cooperative setting, we aimed to investigate whether preoperative dehydration was associated with frailty, prolonged hospital stays and short-term mortality in older patients with hip fractures. METHODS: This retrospective cohort study was conducted in a Danish university hospital. The study population consisted of patients 65+ years surgically treated for hip fracture. Dehydration was defined as serum calculated osmolarity above 295 mmol/L. Outcomes were frailty at discharge measured by the Multidimensional Prognostic Index, hospital stay of 7 days or more and 90-day mortality. RESULTS: In total, 214 patients were consecutively included in the study from March 11, 2018, to August 31, 2020. The mean age was 81.2 (SD: 7.6) and 69% of the patients were women. The prevalence of preoperative dehydration was 40%. It was associated with severe frailty (Odds Ratio (OR): 2.08 [95% confidence interval (CI): 1.11-3.90]; p = 0.02) and prolonged hospital stay (OR: 2.28 [95% CI: 1.29-4.04]; p = 0.02). Seven percent died when dehydrated compared to 5% in the non-dehydrated (p = 0.91). CONCLUSION: Prevalence of preoperative dehydration is high among older patients with hip fractures and is associated with severe frailty and length of hospital stay. Systematic screening for dehydration on admission is advisable and may contribute to more adequate fluid management in the perioperative phase.


Assuntos
Fragilidade , Fraturas do Quadril , Humanos , Feminino , Idoso , Idoso de 80 Anos ou mais , Masculino , Fragilidade/complicações , Fragilidade/diagnóstico , Fragilidade/epidemiologia , Estudos Retrospectivos , Desidratação , Fraturas do Quadril/complicações , Fraturas do Quadril/cirurgia , Concentração Osmolar
11.
Environ Sci Technol ; 56(23): 16707-16715, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36378621

RESUMO

Graphene oxide (GO) is a widely used antimicrobial and antibiofouling material in surface modification. Although the antibacterial mechanisms of GO have been thoroughly elucidated, the dynamics of bacterial attachment on GO surfaces under environmentally relevant conditions remain largely unknown. In this study, quartz crystal microbalance with dissipation monitoring (QCM-D) was used to examine the dynamic attachment processes of a model organism Pseudomonas aeruginosa PAO1 onto GO surface under different ionic strengths (1-600 mM NaCl). Our results show the highest bacterial attachment at moderate ionic strengths (200-400 mM). The quantitative model of QCM-D reveals that the enhanced bacterial attachment is attributed to the higher contact area between bacterial cells and GO surface. The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory and atomic force microscopy (AFM) analysis were employed to reveal the mechanisms of the bacteria-GO interactions under different ionic strengths. The strong electrostatic and steric repulsion at low ionic strengths (1-100 mM) was found to hinder the bacteria-GO interaction, while the limited polymer bridging caused by the collapse of biopolymer layers reduced cell attachment at a high ionic strength (600 mM). These findings advance our understanding of the ionic strength-dependent bacteria-GO interaction and provide implications to further improve the antibiofouling performance of GO-modified surfaces.


Assuntos
Grafite , Pseudomonas aeruginosa , Grafite/química , Concentração Osmolar , Técnicas de Microbalança de Cristal de Quartzo , Propriedades de Superfície
12.
Sci Rep ; 12(1): 19692, 2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36385111

RESUMO

Growing evidence suggests that sustained concentrated urine contributes to chronic metabolic and kidney diseases. Recent results indicate that a daily urinary concentration of 500 mOsm/kg reflects optimal hydration. This study aims at providing personalized advice for daily water intake considering personal intrinsic (age, sex, height, weight) and extrinsic (food and fluid intakes) characteristics to achieve a target urine osmolality (UOsm) of 500 mOsm/kg using machine learning and optimization algorithms. Data from clinical trials on hydration (four randomized and three non-randomized trials) were analyzed. Several machine learning methods were tested to predict UOsm. The predictive performance of the developed algorithm was evaluated against current dietary guidelines. Features linked to urine production and fluid consumption were listed among the most important features with relative importance values ranging from 0.10 to 0.95. XGBoost appeared the most performing approach (Mean Absolute Error (MAE) = 124.99) to predict UOsm. The developed algorithm exhibited the highest overall correct classification rate (85.5%) versus that of dietary guidelines (77.8%). This machine learning application provides personalized advice for daily water intake to achieve optimal hydration and may be considered as a primary prevention tool to counteract the increased incidence of chronic metabolic and kidney diseases.


Assuntos
Ingestão de Líquidos , Aprendizado de Máquina , Adulto , Humanos , Algoritmos , Política Nutricional , Concentração Osmolar , Ensaios Clínicos Controlados Aleatórios como Assunto , Ensaios Clínicos Controlados não Aleatórios como Assunto
13.
BMC Vet Res ; 18(1): 398, 2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36368996

RESUMO

BACKGROUND: One of the contributing factors to ocular surface health is a stable precorneal tear film. Considering the increasing interest in rabbits as pets and the limited literature available on domestic rabbit tearing, the aim of this study was to establish normative data for examination of the tear film in domestic rabbits. RESULTS: The study included 75 client-owned domestic Holland Lop rabbits (150 eyes). The following examinations were performed in each eye: Schirmer tear test-1, tear osmometry, interferometry, tear meniscus height measurement and meibography (quantifying meibomian gland loss as a percentage). The resulting median (95% central range) values were 10.0 (5.0-17.3) mm/min for the Schirmer tear test-1, 345.0 (280.5-376.1) mOsm/L for tear osmolarity, grade 2 (1-4) of interferometry, 0.28 (0.20-0.47) mm for tear meniscus height and 0.0 (0.0-67.6) % meibomian gland loss. A significant association was found between tear osmolarity and age, with an estimated decrease of - 4.0 mOsm/L with each additional year of age (p < 0.001). The distributions of interferometry grades were significantly different between males and females (p < 0.001), with grade 1 and grade 2 being the most frequent in females and males, respectively. A weak negative correlation was also observed between interferometry grade and the percentage of meibomian gland loss (r = - 0.22, p = 0.006). CONCLUSIONS: This is an original study that documents extensive tear film parameters in healthy Holland Lop rabbits. The results can be used as normative data for the examination of the tear film in this lagomorph breed.


Assuntos
Síndromes do Olho Seco , Masculino , Feminino , Animais , Coelhos , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/veterinária , Lágrimas , Glândulas Tarsais/diagnóstico por imagem , Concentração Osmolar , Exame Físico
14.
Sci Rep ; 12(1): 19261, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36357497

RESUMO

Slime expelled by velvet worms entraps prey insects within seconds in a hardened biopolymer network that matches the mechanical strength of industrial polymers. While the mechanic stimuli-responsive nature and building blocks of the polymerization are known, it is still unclear how the velvet worms' slime hardens so fast. Here, we investigated the slime for the first time, not only after, but also before expulsion. Further, we investigated the slime's micro- and nanostructures in-depth. Besides the previously reported protein nanoglobules, carbohydrates, and lipids, we discovered abundant encapsulated phosphate and carbonate salts. We also detected CO2 bubbles during the hardening of the slime. These findings, along with further observations, suggest that the encapsulated salts in expelled slime rapidly dissolve and neutralize in a baking-powder-like reaction, which seems to accelerate the drying of the slime. The proteins' conformation and aggregation are thus influenced by shear stress and the salts' neutralization reaction, increasing the slime's pH and ionic strength. These insights into the drying process of the velvet worm's slime demonstrate how naturally evolved polymerizations can unwind in seconds, and could inspire new polymers that are stimuli-responsive or fast-drying under ambient conditions.


Assuntos
Nanoestruturas , Sais , Proteínas/química , Biopolímeros , Concentração Osmolar
15.
Molecules ; 27(21)2022 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-36364414

RESUMO

Penicillin G acylase (PGA) from Escherichia coli was immobilized on vinyl sulfone (VS) agarose. The immobilization of the enzyme failed at all pH values using 50 mM of buffer, while the progressive increase of ionic strength permitted its rapid immobilization under all studied pH values. This suggests that the moderate hydrophobicity of VS groups is enough to transform the VS-agarose in a heterofunctional support, that is, a support bearing hydrophobic features (able to adsorb the proteins) and chemical reactivity (able to give covalent bonds). Once PGA was immobilized on this support, the PGA immobilization on VS-agarose was optimized with the purpose of obtaining a stable and active biocatalyst, optimizing the immobilization, incubation and blocking steps characteristics of this immobilization protocol. Optimal conditions were immobilization in 1 M of sodium sulfate at pH 7.0, incubation at pH 10.0 for 3 h in the presence of glycerol and phenyl acetic acid, and final blocking with glycine or ethanolamine. This produced biocatalysts with stabilities similar to that of the glyoxyl-PGA (the most stable biocatalyst of this enzyme described in literature), although presenting just over 55% of the initially offered enzyme activity versus the 80% that is recovered using the glyoxyl-PGA. This heterofuncionality of agarose VS beads opens new possibilities for enzyme immobilization on this support.


Assuntos
Penicilina Amidase , Penicilina Amidase/química , Sefarose/química , Prostaglandinas A , Enzimas Imobilizadas/química , Escherichia coli/metabolismo , Concentração Osmolar , Estabilidade Enzimática , Concentração de Íons de Hidrogênio
16.
J Control Release ; 352: 766-775, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36343763

RESUMO

Colorectal cancer (CRC) is the second most deadly cancer worldwide, with chemoresistance remaining a major obstacle in CRC treatment. Sodium persulfate (Na2S2O8) is a novel agent capable of producing •SO4- and Na+ for chemodynamic therapy (CDT). This can induce pyroptosis and ferroptosis instead of conventional apoptosis in tumor cells. Meanwhile, IR780-iodide (IR780), as an excellent phototherapy agent, can generate hyperthermia and generate a large amount of reactive oxygen species (ROS) to synergize with the CDT of Na2S2O8, with potential to overcome chemoresistance in CRC. However, the low stability of Na2S2O8 and the poor solubility of IR780 limit their applications in the medical field. Accordingly, for the first time, D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS), Na2S2O8 and IR780 were rationally designed in a cascade-amplifying nanoplatform (Na2S2O8-IR780 NPs) via a co-assembly strategy. Combining Na2S2O8 and IR780 in a nanoplatform improves the stability of Na2S2O8 and the solubility of IR780. As a result, the Na2S2O8-IR780 NPs exhibited excellent antitumor efficacy in CRC cell lines and five chemo-resistant cell lines and showed potent inhibitory capability in nude mice xenograft models. This photo-chemodynamic nanoplatform provides a brand-new paradigm by manipulating osmolarity and redox homeostasis to overcome chemo-resistance and holds great potential for the treatment of CRC.


Assuntos
Neoplasias Colorretais , Hipertermia Induzida , Nanopartículas , Camundongos , Animais , Humanos , Camundongos Nus , Indóis , Fototerapia , Oxirredução , Concentração Osmolar , Homeostase , Neoplasias Colorretais/tratamento farmacológico , Linhagem Celular Tumoral
17.
J Stroke Cerebrovasc Dis ; 31(12): 106867, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36334372

RESUMO

INTRODUCTION: Animal experiments recently demonstrated that replacing urinary loses with crystalloid diminishes the therapeutic effect of mannitol by reducing the increase in osmolality. We aimed to investigate whether this effect is similarly seen in in brain-injured patients by studying the association between total body fluid balance (TBB) and the osmolar response to mannitol. METHODS: We performed a retrospective cohort study of adult patients with acute brain injury between 2015 and 2021 who received ≥ 2 doses of mannitol within 8 hours and no intercurrent concentrated saline solution. We analyzed the association between the change in TBB (∆TBB) and change in osmolality (∆Osm) before and after mannitol in a linear model, both as univariate and after adjustment for common confounding factors. RESULTS: Of 6,145 patients who received mannitol, 155 patients met inclusion criteria (mean age 60 ± 17 years, 48% male, 83% white). The mean total mannitol dose was 2 ± 0.5 g/kg and the mean change in plasma osmolality was 7.9 ± 7.1 mOsm/kg. Each 1 L increase in ∆TBB was associated with a change of -1.1 mOsm/L in ∆Osm (95% CI [-2.2, -0.02], p = 0.045). The magnitude of association was similar to that of total mannitol dose and remained consistent in an adjusted model and after excluding outliers. CONCLUSIONS: In patients with acute brain injury, a positive TBB is associated with a diminished mannitol-induced increase in plasma osmolality. Future prospective studies are needed to confirm these findings and their influence on the therapeutic effect of mannitol.


Assuntos
Lesões Encefálicas , Manitol , Animais , Masculino , Feminino , Manitol/efeitos adversos , Estudos Retrospectivos , Lesões Encefálicas/diagnóstico , Lesões Encefálicas/tratamento farmacológico , Concentração Osmolar , Equilíbrio Hidroeletrolítico
18.
Water Res ; 226: 119286, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36323211

RESUMO

In this study, the aggregation behavior of polystyrene nanoplastics (PS NPs) in the absence or presence of oppositely charged particulate matters is systematically investigated for a wide range of electrolyte conditions. Herein, we used isothermal titration calorimetry combined with time-resolved dynamic light scattering to provide kinetic and thermodynamic insights into the NP aggregation. The thermodynamic profiles of homoaggregation and heteroaggregation were fit using an independent site and two independent sites models, respectively, demonstrating different interaction modes of both aggregation processes. We found that the contribution of solvation entropy was significant and variable in most cases, and this thermodynamic parameter was a large determinant of the thermodynamics of NP aggregation. Furthermore, the stability of PS NPs in natural water matrices was found to be correlated with ionic strength and the content of natural colloids (e.g., metal oxides and clay particles). These results point to the importance of considering the role of thermodynamic variables when studying the fate of NPs within various environmental conditions.


Assuntos
Microplásticos , Nanopartículas , Nanopartículas/química , Poliestirenos/química , Concentração Osmolar , Termodinâmica
19.
Anal Chem ; 94(45): 15604-15612, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36315456

RESUMO

Understanding how environmental factors affect the bioelectrode efficiency and stability is of uttermost importance to develop high-performance bioelectrochemical devices. By coupling fluorescence confocal microscopy in situ to electrochemistry, this work focuses on the influence of the ionic strength on electro-enzymatic catalysis. In this context, the 4 e-/4 H+ reduction of O2 into water by the bilirubin oxidase from Myrothecium verrucaria (MvBOD) is considered as a model. The effects of salt concentration on the enzyme activity and stability were probed by enzymatic assays performed in homogeneous catalysis conditions and monitored by UV-vis absorption spectroscopy. They were also investigated in heterogeneous catalysis conditions by electrochemical measurements with MvBOD immobilized at a graphite microelectrode. We demonstrate that the catalytic activity and stability of the enzyme both in solution and in the immobilized state at the bioelectrode were conserved with an electrolyte concentration of up to 0.5 M, both in a buffered and a non-buffered electrolyte. Relying on this, we used fluorescence confocal laser scanning microscopy coupled in situ to electrochemistry to explore the local pH of the electrolyte at the vicinity of the electrode surface at various ionic strengths and for several overpotentials. 3D proton depletion profiles generated by the interfacial electro-enzymatic reaction were recorded in the presence of a pH-sensitive fluorophore. These concentration profiles were shown to contract with increasing ionic strength, thus highlighting the need for a minimal electrolyte concentration to ensure availability of charged substrates at the electrode surface during electro-enzymatic experiments.


Assuntos
Eletrodos , Eletroquímica , Catálise , Concentração Osmolar , Concentração de Íons de Hidrogênio , Microscopia de Fluorescência
20.
Environ Pollut ; 315: 120306, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36181928

RESUMO

The ionic strength of infiltration water changes with the seasonal alternation of irrigation sources. In this study, reactivity changes of birnessite-coated sand with the fluctuations of ionic strength of infiltration water (i.e. from groundwater to rainwater) and the involved mechanism were investigated through column experiments. Birnessite-coated sand was less reactive in groundwater than in rainwater because of the higher cation content and higher pH of groundwater. The cations in the groundwater were adsorbed on birnessite-coated sand and then desorbed in presence of a dilute aqueous solution represented by rainwater. The reactivity of the passivated birnessite-coated sand was recovered instantaneously, and approximately one-third of the pristine reactivity was restored. During recovery, Na+ desorption and lincomycin (LIN) removal both exhibited a two-stage reaction pattern. The LIN removal correlated with Na+ desorption (r = 0.99) so that the reactive sites that were binding 5.602 µmol of Na+ became available for 1 µmol of LIN removal. These results suggest that the reactivity of manganese oxides toward organic contaminant is associated with the ionic strength of infiltration water and indicate that the partial reactivity can be naturally restored.


Assuntos
Areia , Água , Lincomicina , Óxidos/química , Concentração Osmolar , Cátions , Oxirredução
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