Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Trop Life Sci Res ; 35(1): 33-47, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39262861

RESUMO

Rhamnolipid has gained much attention in various fields owing to its distinctive functional properties compared to conventional chemical surfactants, which are mostly derived from petroleum feedstock. Production cost is one of the main challenges in rhamnolipid production, particularly when using refined substrates. One possible solution is to use agro-industrial wastes as substrates for rhamnolipid production. This is a promising strategy due to their abundance and commercially low value, while simultaneously alleviating an agro-industrial waste management problem in the environment. This study aims to evaluate agro-industrial wastes from local crops as possible low-cost alternative substrates for rhamnolipid production by a local isolate, Pseudomonas aeruginosa USM-AR2. Various liquid wastes, namely sugarcane molasses, rice washing water, overly mature coconut (OMC) water, empty fruit bunch (EFB) steam effluent, palm sludge oil (PSO) and palm oil mill effluent (POME) were screened as the main carbon source supplementing mineral salt medium (MSM) in the fermentation of P. aeruginosa USM-AR2. Batch fermentation was carried out in a shake flask system, agitated at 200 rpm and incubated at room temperature, 27 ± 2°C for 120 h. Among the substrates tested, PSO exhibited the highest biomass at 20.78 g/L and rhamnolipid production at 1.07 g/L. This study has shown the potential of agro-industrial wastes in Malaysia as an alternative resource for rhamnolipid production, transforming them into value added products, while reducing the amount of wastes discharged into the environment.

2.
Pak J Med Sci ; 40(7): 1425-1429, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39092024

RESUMO

Background & Objective: Miscarriage, a common complication of early pregnancy before 12 completed weeks of gestation, is typically managed medically. We aimed to estimate the success and complication rate of medical management in women with first-trimester missed miscarriages. Our objective was to calculate the rate of complete uterine evacuation within three weeks of treatment, rate of infection, significant blood loss, re-admission, or surgical evacuation. Methods: It was a retrospective cross-sectional study that included women diagnosed with miscarriage at less than 13 weeks' gestation in Latifa Hospital's Gynecology Department from January 2019 to December 2019 in Dubai. These patients were given vaginal misoprostol, 400-800 mcg every 6-8 hours until expulsion of pregnancy. Results: There were 294 women included in the study. The success rate was 60.5% (178/294). Twenty women developed significant blood loss (6.8%), four women developed infection (1.4%), 76 required readmission (25.9%), 12 women received blood transfusion (4.1%), and 74 women required a surgical evacuation (25.2%). Nulliparity, unscarred uterus, and the presence of abdominal pain with vaginal bleeding before treatment were significantly associated with the successful medical treatment (p<0.05). Conclusion: The success rate of the medical regimen studied lies on the lower end of what is quoted in the literature. The difference in the success rate could be attributed to the different definitions of success in other studies. Nulliparity, unscarred uterus and presence of abdominal pain with vaginal bleeding were associated with higher success.

3.
Biotechnol Prog ; : e3500, 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39073020

RESUMO

Human serum albumin (HSA) is currently used as a plasma expander (PE) to increase blood volume during hypovolemic conditions, such as blood loss. However, its effectiveness is suboptimal in septic shock and burn patients due to their enhanced endothelial permeability, resulting in HSA extravasation into the tissue space leading to edema, and deposition of toxic HSA-bound metabolites. Hence, to expand HSA's applicability toward treating patients with compromised endothelial permeability, HSA has been previously polymerized to increase its molecular size thus compartmentalizing the polymerized HSA (PolyHSA) molecules in the vascular space. Previous studies bracketed PolyHSA between 100 kDa and 0.2 µm. In this research, PolyHSA was synthesized at two cross-link densities 43:1 and 60:1 (i.e., molar ratios of glutaraldehyde to HSA) and subsequently fractionated via tangential flow filtration (TFF) into two narrower brackets: bracket A (500 kDa and 0.2 µm) and bracket B (50-500 kDa). PolyHSA within the same size bracket at different cross-link densities exhibited similar solution viscosity, zeta potential, and osmolality but differed in hydrodynamic diameter. At the same cross-link density, the PolyHSA A bracket showed higher viscosity, lowered zeta potential, and a larger hydrodynamic diameter compared with the PolyHSA B bracket while maintaining osmolality. Interestingly, PolyHSA 43:1 B, PolyHSA 60:1 A, and PolyHSA 60:1 B brackets exhibited colloid osmotic pressure similar to HSA, indicating their potential to serve as PEs.

4.
J Basic Microbiol ; 64(4): e2300585, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38346247

RESUMO

This study aimed to isolate biosurfactant-producing and hydrocarbon-degrading actinomycetes from different soils using glycerol-asparagine and starch-casein media with an antifungal agent. The glycerol-asparagine agar exhibited the highest number of actinomycetes, with a white, low-opacity medium supporting pigment production and high growth. Biosurfactant analyses, such as drop collapse, oil displacement, emulsification, tributyrin agar test, and surface tension measurement, were conducted. Out of 25 positive isolates, seven could utilize both olive oil and black oil for biosurfactant production, and only isolate RP1 could produce biosurfactant when grown in constrained conditions with black oil as the sole carbon source and inducer, demonstrating in situ bioremediation potential. Isolate RP1 from oil-spilled garden soil is Gram-staining-positive with a distinct earthy odor, melanin formation, and white filamentous colonies. It has a molecular size of ~621 bp and 100% sequence similarity to many Streptomyces spp. Morphological, biochemical, and 16 S rRNA analysis confirmed it as Streptomyces sp. RP1, showing positive results in all screenings, including high emulsification activity against kerosene (27.2%) and engine oil (95.8%), oil displacement efficiency against crude oil (7.45 cm), and a significant reduction in surface tension (56.7 dynes/cm). Streptomyces sp. RP1 can utilize citrate as a carbon source, tolerate sodium chloride, resist lysozyme, degrade petroleum hydrocarbons, and produce biosurfactant at 37°C in a 15 mL medium culture, indicating great potential for bioremediation and various downstream industrial applications with optimization.


Assuntos
Actinobacteria , Petróleo , Streptomyces , Actinobacteria/genética , Actinobacteria/metabolismo , Streptomyces/genética , Streptomyces/metabolismo , Actinomyces/metabolismo , Biodegradação Ambiental , Ágar , Glicerol , Asparagina , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Carbono , Tensoativos/química
5.
Front Immunol ; 14: 1291534, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38149243

RESUMO

Background: Adaptive humoral immunity against SARS-CoV-2 has mainly been evaluated in peripheral blood. Human secondary lymphoid tissues (such as tonsils) contain large numbers of plasma cells that secrete immunoglobulins at mucosal sites. Yet, the role of mucosal memory immunity induced by vaccines or natural infection against SARS-CoV-2 and its variants is not fully understood. Methods: Tonsillar mononuclear cells (TMNCs) from adults (n=10) and children (n=11) were isolated and stimulated using positive SARS-CoV-2 nasal swabs. We used endpoint enzyme-linked immunosorbent assays (ELISAs) for the measurement of anti-S1, -RBD, and -N IgG antibody levels and a pseudovirus microneutralization assay to assess neutralizing antibodies (nAbs) in paired serum and supernatants from stimulated TMNCs. Results: Strong systemic humoral response in previously SARS-CoV-2 infected and vaccinated adults and children was observed in accordance with the reported history of the participants. Interestingly, we found a significant increase in anti-RBD IgG (305 and 834 folds) and anti-S1 IgG (475 and 443 folds) in the stimulated TMNCs from adults and children, respectively, compared to unstimulated cells. Consistently, the stimulated TMNCs secreted higher levels of nAbs against the ancestral Wuhan strain and the Omicron BA.1 variant compared to unstimulated cells by several folds. This increase was seen in all participants including children with no known history of infection, suggesting that these participants might have been previously exposed to SARS-CoV-2 and that not all asymptomatic cases necessarily could be detected by serum antibodies. Furthermore, nAb levels against both strains were significantly correlated in adults (r=0.8788; p = 0.0008) and children (r = 0.7521; p = 0.0076), and they strongly correlated with S1 and RBD-specific IgG antibodies. Conclusion: Our results provide evidence for persistent mucosal humoral memory in tonsils from previously infected and/or vaccinated adults and children against recent and old variants upon re-exposure. They also highlight the importance of targeting mucosal sites with vaccines to help control infection at the primary sites and prevent potential breakthrough infections.


Assuntos
COVID-19 , Vacinas , Adulto , Criança , Humanos , Imunidade Humoral , Tonsila Palatina , SARS-CoV-2 , Imunoglobulina G , Anticorpos Neutralizantes
6.
Mol Pharm ; 20(11): 5739-5752, 2023 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-37843033

RESUMO

Polymerized human hemoglobin (PolyhHb) has shown promise in preclinical hemorrhagic shock settings. Different synthetic and purification schemes can control the size of PolyhHbs, yet research is lacking on the impact of polymerized hemoglobin size on tissue oxygenation following hemorrhage and resuscitation in specialized animal models that challenge their resuscitative capabilities. Pre-existing conditions that compromise the vasculature and end organs, such as the liver, may limit the effectiveness of resuscitation and exacerbate the toxicity of these molecules, which is an important but minimally explored therapeutic dimension. In this study, we compared the effective oxygen delivery of intermediate molecular weight PolyhHb (PolyhHb-B3; 500-750 kDa) to high molecular weight PolyhHb (PolyhHb-B4; 750 kDa-0.2 µm) for resuscitative effectiveness in guinea pig models subjected to hemorrhagic shock. We evaluated how the size of PolyhHb impacts hemodynamics and tissue oxygenation in normal guinea pigs and guinea pigs on an atherogenic diet. We observed that while PolyhHb-B3 and -B4 equivalently restore hemodynamic parameters of normal-dieted guinea pigs, high-fat-dieted guinea pigs resuscitated with PolyhHb-B4 have lower mean arterial pressures, impaired tissue oxygenation, and higher plasma lactate levels than those receiving PolyhHb-B3. We characterized the plasma of these animals following resuscitation and found that despite similar oxygen delivery kinetics, circulating PolyhHb-B3 and -B4 demonstrated a size-dependent increase in the plasma viscosity, consistent with impaired perfusion in the PolyhHb-B4 transfusion group. We conclude that intermediate-sized PolyhHbs (such as -B3) are ideal for further research given the effective resuscitation of hemorrhagic shock based on tissue oxygenation in hypercholesterolemic guinea pigs.


Assuntos
Hipercolesterolemia , Choque Hemorrágico , Humanos , Cobaias , Animais , Choque Hemorrágico/tratamento farmacológico , Hipercolesterolemia/tratamento farmacológico , Oxigênio , Hemodinâmica , Hemoglobinas
7.
Lett Appl Microbiol ; 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37164939

RESUMO

This study aims to evaluate rhamnolipid production by immobilized Pseudomonas aeruginosa USM-AR2 cells using waste cooking oil (WCO) as the carbon source. P. aeruginosa USM-AR2 cells were entrapped in polyvinyl alcohol (PVA)-alginate hydrogel beads. The performance of entrapped cells was compared with free cells in shake flasks before cultivation in a custom-designed fluidized bed reactor (FBR). A mass of 1 g wet cells entrapped in PVA-alginate hydrogel beads were successfully recycled 3 times in shake flasks at 200 rpm, producing between 0.66-1.34 g L-1 rhamnolipid after 120 h. Meanwhile, cultivation of entrapped cells in FBR with broth recirculation showed that the suitable hydrogel beads to medium ratio was 1:20 ratio at an aeration rate of 0.5 vvm, producing between 0.77 to 1.58 g L-1 rhamnolipid, degrading 8.67 to 20.93 g L-1 of waste cooking oil in 15 cycles of repeated batch cultivation. Entrapped P. aeruginosa USM-AR2 cells achieved a higher rhamnolipid production, by 1.03-fold during cycle 3 in shake flasks and 1.19-fold during cycle 11 in an FBR, compared to free cells. These results show that entrapment enables reusability of viable cells and maintains stability of rhamnolipid production throughout the extended cultivation, increasing cell tolerance to perturbations in fermentation conditions.

8.
Biomacromolecules ; 24(4): 1855-1870, 2023 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-36877888

RESUMO

Red blood cell (RBC) substitutes tested in late-phase clinical trials contained low-molecular-weight hemoglobin species (<500 kDa), resulting in vasoconstriction, hypertension, and oxidative tissue injury; therefore, contributing to poor clinical outcomes. This work aims to improve the safety profile of the RBC substitute, polymerized human hemoglobin (PolyhHb), via in vitro and in vivo screening of PolyhHb fractionated into four molecular weight brackets (50-300 kDa [PolyhHb-B1]; 100-500 kDa [PolyhHb-B2]; 500-750 kDa [PolyhHb-B3]; and 750 kDa to 0.2 µm [PolyhHb-B4]) using a two-stage tangential flow filtration purification process. Analysis showed that PolyhHb's oxygen affinity, and haptoglobin binding kinetics decreased with increasing bracket size. A 25% blood-for-PolyhHb exchange transfusion guinea pig model suggests that hypertension and tissue extravasation decreased with increasing bracket size. PolyhHb-B3 demonstrated extended circulatory pharmacokinetics, no renal tissue distribution, no aberrant blood pressure, or cardiac conduction effects, and may therefore be appropriate material for further evaluation.


Assuntos
Substitutos Sanguíneos , Hemoglobinas , Humanos , Animais , Cobaias , Hemoglobinas/química , Oxigênio/metabolismo , Polimerização , Substitutos Sanguíneos/farmacologia , Eritrócitos/metabolismo
9.
Healthcare (Basel) ; 11(3)2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36766886

RESUMO

Little is known about the changes in perception of illness among patients with the acute coronary syndrome (ACS) during cardiac rehabilitation programme (CRP). The purpose of this study is to determine changes in perception of illness with ACS patients during CRP to evaluate the association of patients' characteristics with the perception of illness at the end of Phase II of CRP. A descriptive longitudinal study was conducted among 450 patients who attended 8-weeks of Phase II CRP at 2 public hospitals in Malaysia and perception of illness was assessed using Brief Illness Perception Questionnaire (BIPQ). The assessment was conducted before Phase II (T0), during the 4th session (T1), and at the end of right after the 8th session (T2). One-way repeated measures of ANOVA analysed the changes of perception at T1 and T2 while logistic regression analysis evaluated the association of patients' characteristics with the perception of illness at T2. Perception of illness changed during and after CRP from T0 to T1, and T1 to T2 (p < 0.001). The patient viewed ACS as an illness that changed from being more acute to a chronic condition as the sessions progressed. Previous history of acute myocardial infarction (OR = 2.380, 95% CI 1.46, 5.49) and angioplasty intervention were both found to be associated with the perception of illness (OR = 3.857, 95% CI 1.55, 9.61). Perception of illness changed during CRP and these changes are associated with patients' previous history of cardiac events. Phase II can be viewed as the second window of opportunity for healthcare professionals to intervene early in modifying the perception of illness.

10.
Artigo em Inglês | MEDLINE | ID: mdl-36613165

RESUMO

The contraceptive use profile is poorly understood in some Gulf Arabian countries, including Saudi Arabia. The present study aimed to assess the knowledge, attitude, and practices related to contraceptive use among women of childbearing age in Jazan city, Saudi Arabia. An observational, analytical cross-sectional study was conducted among a random sample of 450 women in Jazan city. The data were obtained through personal interviews using a questionnaire that included questions on women's level of knowledge about contraception methods, their attitudes towards contraception methods, and their practices. Data were analyzed using descriptive and inferential statistics techniques using the SPSS program. The prevalence of ever having used contraceptives was significantly different according to age group, job status, children ever born, and the number of pregnancies (p < 0.05 for all). On the other hand, the prevalence of desire to use the contraceptives in the future was high, at 70.9%, with a 95% CI [66.5-74.9]. It differed significantly according to age group and job status (p < 0.05 for both). The most familiar and usable types of contraceptives were pills (36.3%) and intrauterine devices (24.4%). When asked their reasons for using contraceptives, 53.8% of participants cited child spacing and 21.8% improving child health. Logistic regression revealed that the use of contraception among women was more associated with the 20-34 age group [COR = 7.7, 95% CI = 4.4-13.5, p < 0.001] than the 15-24 age group. Having more than one pregnancy and having more than one child were also associated with increased use of contraceptive methods (p < 0.001 for both). These results indicate there is a high level of awareness about contraceptives, a positive attitude toward them, and good practices for the use of them among Saudi women in Jazan. More efforts are needed to improve women's awareness for better utilization of the available services.


Assuntos
Anticoncepção , Anticoncepcionais , Criança , Feminino , Humanos , Gravidez , Comportamento Contraceptivo , Estudos Transversais , Conhecimentos, Atitudes e Prática em Saúde , Arábia Saudita
11.
Front Mol Biosci ; 9: 1011981, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36339713

RESUMO

Assessing the structure of living microbial cell membranes is a challenging analytical goal. The cell membrane is defined by its transverse structure, an approximately 5 nm-thick selectively permeable bilayer that serves many important cellular functions. Compositionally complex, dynamic, and organized in both the transverse and lateral dimensions, understanding the cell membrane structure-and the role that structure plays in cellular function, communication, and environmental sensing is an active scientific effort. Previously, we have devised a novel isotopic labeling approach for membrane lipids to enable direct in vivo structural studies of the cell membrane in the Gram-positive bacterium, Bacillus subtilis, using small-angle neutron scattering. This was accomplished through a genetic inhibition of fatty acid (FA) degradation (ΔfadN) and a chemical inhibition of FA biosynthesis using cerulenin, an irreversible inhibitor of type II fatty acid synthases. Here, we improve upon the previous system by introducing a dCas9/sgRNA-fabF complex that blocks transcription of the essential fabF gene when under xylose induction. This leads to greater sensitivity to cerulenin in the mutant strain (JEBS102) and more robust cell growth when supplementary FAs are introduced to the culture medium. A subtle change in FA uptake is noted when compared to the prior labeling strategy. This is seen in the gas chromatography/mass spectrometry (GC/MS) data as a higher ratio of n16:0 to a15:0, and manifests in an apparent increase in the membrane thickness determined via neutron scattering. This represents an improved method of isotopic labeling for the cell membrane of Bacillus subtilis; enabling improved investigations of cellular uptake and utilization of FAs, cell membrane structure and organization as a phenotypic response to metabolic and environmental changes.

12.
Am J Case Rep ; 23: e936743, 2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36110038

RESUMO

BACKGROUND Pituitary abscess (PA) is a rare pituitary lesion accounting for less than 1% of all pituitary diseases and is associated with high mortality rates. The non-specific clinical symptoms and radiological features preclude accurate diagnosis of the disease. Hence, surgical intervention is still considered the criterion standard method for PA diagnosis. Most PAs occur as a primary disease or due to complications such as surgery, sepsis, and adjacent inflamed lesions. CASE REPORT A 53-year-old man presented to the Emergency Department with a headache associated with nausea, vomiting, and constipation. The patient had no visual disturbances, polyuria, polydipsia, nocturia, or abnormal discharges. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large suprasellar mass. The patient underwent left-side trans-nasal transsphenoidal microscopic surgery for mass removal. An abscess with discharge was noticed and sent for microbiological evaluation, revealing an infection with a commensal enteric bacterium that rarely causes nosocomial infection, known as Morganella morganii. The patient was discharged after completing the intravenous antibiotic course and was given oral antibiotics. CONCLUSIONS Pituitary abscess is a rare pituitary lesion. However, taking the history of recent meningitis, sinusitis, and/or surgery may help to reach an early diagnosis, prompt surgical intervention, and vital therapeutic steps to reduce mortality rates and improve patient's outcomes. PA should always be considered when patients demonstrate signs of pituitary dysfunction associated with signs of infection. Furthermore, antibiotics should be administered immediately once the PA case is confirmed and should last for at least 6 weeks postoperatively.


Assuntos
Abscesso Encefálico , Morganella morganii , Doenças da Hipófise , Antibacterianos/uso terapêutico , Abscesso Encefálico/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Doenças da Hipófise/diagnóstico , Tomografia Computadorizada por Raios X/efeitos adversos
13.
Biology (Basel) ; 11(8)2022 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-36009841

RESUMO

Mycobacterium tuberculosis has seen tremendous success as it has developed defenses to reside in host alveoli despite various host-related stress circumstances. Rv1636 is a universal stress protein contributing to mycobacterial survival in different host-derived stress conditions. Both ATP and cAMP can be bound with the Rv1636, and their binding actions are independent of one another. ß-Amyrin, a triterpenoid compound, is abundant in medicinal plants and has many pharmacological properties and broad therapeutic potential. The current study uses biochemical, biophysical, and computational methods to define the binding of Rv1636 with ß-Amyrin. A substantial interaction between ß-Amyrin and Rv1636 was discovered by molecular docking studies, which helped decipher the critical residues involved in the binding process. VAL60 is a crucial residue found in the complexes of both Rv1636_ß-Amyrin and Rv1636-ATP. Additionally, the Rv1636_ß-Amyrin complex was shown to be stable by molecular dynamics simulation studies (MD), with minimal changes observed during the simulation. In silico observations were further complemented by in vitro assays. Successful cloning, expression, and purification of Rv1636 were accomplished using Ni-NTA affinity chromatography. The results of the ATPase activity assay indicated that Rv1636's ATPase activity was inhibited in the presence of various ß-Amyrin concentrations. Additionally, circular dichroism spectroscopy (CD) was used to examine modifications to Rv1636 secondary structure upon binding of ß-Amyrin. Finally, isothermal titration calorimetry (ITC) advocated spontaneous binding of ß-Amyrin with Rv1636 elucidating the thermodynamics of the Rv1636_ß-Amyrin complex. Thus, the study establishes that ß-Amyrin binds to Rv1636 with a significant affinity forming a stable complex and inhibiting its ATPase activity. The present study suggests that ß-Amyrin might affect the functioning of Rv1636, which makes the bacterium vulnerable to different stress conditions.

14.
J Rehabil Med ; 54: jrm00295, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-35652930

RESUMO

OBJECTIVE: Female sex is a major barrier to completing a programme of cardiac rehabilitation (CR) after acute coronary syndrome (ACS). Women require significant social support to promote compliance and the ability to cope with CR programme attendance. The aim of this systematic review of qualitative studies was to explore social support among women coping with CR programme attendance at phase II CRP is 3 months after their cardiac event. METHODS: Articles were searched through CINAHL (Cumulative Index and Allied Health Literature), Science Direct and PubMed databases using the following terms: "women", "acute coronary syndrome", "coping", "social support" and "cardiac rehabilitation". RESULTS: A total of 6 articles were selected based on eligibility criteria. Thematic analysis was used to analyse the data using line to line coding into descriptive themes, interpreting further to generate new insights. The 3 most common themes regarding social support for women attending the CR programme were: family support, female as the primary caregiver in the family, and peer support. For most women who perceived themselves as the primary caregiver in the family there was a negative impact on their ability to cope fully with CR programme attendance. On the other hand, encouraging support from family and peers positively improved their coping mechanism for attending the CR programme, leading to improved compliance. CONCLUSION: Women with ACS consider that support from their family plays a vital role as a coping mechanism in their attendance at a CR programme. Healthcare providers should teach the importance of social support among women after discharge to help them cope with CR programme attendance.


Assuntos
Síndrome Coronariana Aguda , Reabilitação Cardíaca , Feminino , Pessoal de Saúde , Humanos , Pesquisa Qualitativa , Apoio Social
15.
Phys Chem Chem Phys ; 24(17): 10069-10078, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35416222

RESUMO

Pulsed field gradient (PFG) NMR in combination with quasielastic neutron scattering (QENS) was used to investigate self-diffusion of water and acetone in Nafion membranes with and without immobilized vanillic acid (VA). Complementary characterization of these membranes was performed by small angle X-ray scattering (SAXS) and NMR relaxometry. This study was motivated by the recent data showing that an organic acid, such as VA, in Nafion can preserve its catalytic activity in the presence of water even at high intra-polymer water concentrations corresponding up to 100% ambient relative humidity. However, there is currently no clear understanding of how immobilized organic acid molecules influence the microscopic transport properties and related structural properties of Nafion. Microscopic diffusion data measured by PFG NMR and QENS are compared for Nafion with and without VA. For displacements smaller than the micrometer-sized domains previously reported for Nafion, the VA addition was not observed to lead to any significant changes in the water and/or acetone self-diffusivity measured by each technique inside Nafion. However, the reported PFG NMR data present evidence of a different influence of acetone concentration in the membranes with and without VA on the water permeance of the interfaces between neighboring micrometer-sized domains. The reported diffusion data are correlated with the results of SAXS structural characterization and NMR relaxation data for water and acetone.


Assuntos
Acetona , Ácido Vanílico , Polímeros de Fluorcarboneto , Espalhamento a Baixo Ângulo , Água/química , Difração de Raios X
16.
Sci Rep ; 12(1): 4021, 2022 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-35256707

RESUMO

The characteristics of the Parkinson's disease tremor reported previously are not applicable to the full spectrum of severity. The characteristics of high- and low-amplitude tremors differ in signal regularity and frequency dispersion, a phenomenon that indicates characterisation should be studied separately based on the severity. The subclinical tremor of Parkinson's disease is close to physiological tremor in terms of amplitude and frequency, and their distinctive features are still undetermined. We aimed to determine joint motion characteristics that are unique to subclinical Parkinson's disease tremors. The tremors were characterised by four hand-arm motions based on displacement and peak frequencies. The rest and postural tremors of 63 patients with Parkinson's disease and 62 normal subjects were measured with inertial sensors. The baseline was established from normal tremors, and the joint motions were compared within and between the two subject groups. Displacement analysis showed that pronation-supination and wrist abduction-adduction are the most and least predominant tremor motions for both Parkinson's disease and normal tremors, respectively. However, the subclinical Parkinson's disease tremor has significant greater amplitude and peak frequency in specific predominant motions compared with the normal tremor. The flexion-extension of normal postural tremor increases in frequency from the proximal to distal segment, a phenomenon that is explainable by mechanical oscillation. This characteristic is also observed in patients with Parkinson's disease but with amplification in wrist and elbow joints. The contributed distinctive characteristics of subclinical tremors provide clues on the physiological manifestation that is a result of the neuromuscular mechanism of Parkinson's disease.


Assuntos
Tremor Essencial , Doença de Parkinson , Mãos , Humanos , Doença de Parkinson/complicações , Tremor/etiologia , Articulação do Punho
17.
Molecules ; 26(21)2021 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-34770823

RESUMO

Here, we report the extracellular biosynthesis of silver nanoparticles (AgNPs) and determination of their antibacterial and anticancer properties. We also explore the efficacy of bioAgNPs incorporated in cellulose nanocrystals (CNCs) and alginate (Alg) for the formation of an antibacterial hydrogel film. Streptomyces sp. PBD-311B was used for the biosynthesis of AgNPs. The synthesized bioAgNPs were characterized using UV-Vis spectroscopy, TEM, XRD, and FTIR analysis. Then, the bioAgNPs' antibacterial and anticancer properties were determined using TEMA and cytotoxicity analysis. To form the antibacterial hydrogel film, bioAgNPs were mixed with a CNC and Alg solution and further characterized using FTIR analysis and a disc diffusion test. The average size of the synthesized bioAgNPs is around 69 ± 2 nm with a spherical shape. XRD analysis confirmed the formation of silver nanocrystals. FTIR analysis showed the presence of protein capping at the bioAgNP surface and could be attributed to the extracellular protein binding to bioAgNPs. The MIC value of bioAgNPs against P. aeruginosa USM-AR2 and MRSA was 6.25 mg/mL and 3.13 mg/mL, respectively. In addition, the bioAgNPs displayed cytotoxicity effects against cancer cells (DBTRG-0.5MG and MCF-7) and showed minimal effects against normal cells (SVG-p12 and MCF-10A), conferring selective toxicity. Interestingly, the bioAgNPs still exhibited inhibition activity when incorporated into CNC/Alg, which implies that the hydrogel film has antibacterial properties. It was also found that bioAgNP-CNC/Alg displayed a minimal or slow release of bioAgNPs owing to the intermolecular interaction and the hydrogel's properties. Overall, bioAgNP-CNC/Alg is a promising antibacterial hydrogel film that showed inhibition against the pathogenic bacteria P. aeruginosa and MRSA and its application can be further evaluated for the inhibition of cancer cells. It showed benefits for surgical resection of a tumor to avoid post-operative wound infection and tumor recurrence at the surgical site.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Hidrogéis/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/farmacologia , Streptomyces/química , Antibacterianos/biossíntese , Antibacterianos/química , Antineoplásicos/química , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Hidrogéis/síntese química , Hidrogéis/química , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Prata/química , Prata/metabolismo , Streptomyces/metabolismo
18.
Malays Fam Physician ; 16(1): 121-123, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33948151

RESUMO

Ectopic pregnancy is an extra-uterine pregnancy and is a potentially life-threatening condition that can lead to death from intra-peritoneal hemorrhage. This case reports a rare occurrence of ruptured tubal pregnancy in which the patient presented early with abdominal pain and a negative urine pregnancy test but subsequently presented again with evidence of intra-peritoneal hemorrhage. A negative urine pregnancy test is often used to rule out pregnancy, but it is not 100% sensitive. Complete assessment is critical in this important diagnosis in order to plan for the appropriate emergency management.

19.
Bioprocess Biosyst Eng ; 44(7): 1577-1592, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33687550

RESUMO

The present study focused on lipopeptide biosurfactant production by Streptomyces sp. PBD-410L in batch and fed-batch fermentation in a 3-L stirred-tank reactor (STR) using palm oil as a sole carbon source. In batch cultivation, the impact of bioprocessing parameters, namely aeration rate and agitation speed, was studied to improve biomass growth and lipopeptide biosurfactant production. The maximum oil spreading technique (OST) result (45 mm) which corresponds to 3.74 g/L of biosurfactant produced, was attained when the culture was agitated at 200 rpm and aeration rate of 0.5 vvm. The best aeration rate and agitation speed obtained from the batch cultivation was adopted in the fed-batch cultivation using DO-stat feeding strategy to further improve the lipopeptide biosurfactant production. The lipopeptide biosurfactant production was enhanced from 3.74 to 5.32 g/L via fed-batch fermentation mode at an initial feed rate of 0.6 mL/h compared to that in batch cultivation. This is the first report on the employment of fed-batch cultivation on the production of biosurfactant by genus Streptomyces.


Assuntos
Biotecnologia/métodos , Microbiologia Industrial/métodos , Lipopeptídeos/química , Óleo de Palmeira/química , Streptomyces/metabolismo , Técnicas de Cultura Celular por Lotes/métodos , Biomassa , Reatores Biológicos , Carbono , Meios de Cultura , Fermentação , Tensoativos , Fatores de Tempo
20.
J Phys Chem B ; 124(40): 8943-8950, 2020 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-32931279

RESUMO

Pulsed field gradient (PFG) NMR at high field was utilized to directly observe a transition between two different diffusion regimes in a Nafion 117 membrane loaded with water and acetone. Although water self-diffusivity at small water loadings was observed to be diffusion time-independent in the limit of small and large diffusion times, it showed a significant decrease with increasing diffusion time at intermediate times corresponding to root mean square displacements on the order of several microns. Under our experimental conditions, no self-diffusivity dependence on diffusion time was found for water at large water loadings and for acetone at all studied acetone loadings. The diffusion time-dependent self-diffusivity at small water concentration is explained by the existence of finite domains of interconnected water channels with sizes in the range of several microns that form in Nafion in the presence of acetone. The domain sizes and permeance of transport barriers separating adjacent domains are estimated based on the measured PFG NMR data. At large water concentrations, the water channels form a fully interconnected network, resulting in time-independent self-diffusivity. The absence of such a percolation-like transition with increasing molecular concentration for acetone is attributed to a difference in the regions available for water and acetone diffusion in Nafion. The diffusion data are correlated with and supported by structural data obtained using small-angle X-ray and neutron scattering techniques. These techniques reveal distinct water channels with radial dimensions in the nanometer range increasing upon water addition, while acetone appears to be in an interfacial perfluoroether region, reducing the size of the radial channel dimension.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA