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1.
J Environ Manage ; 370: 122944, 2024 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-39418715

RESUMO

Acidic fermentation (AF) of organic waste/wastewater generates valuable byproducts, including hydrogen, volatile fatty acids, and ethanol; however, its sensitivity to pH drops limits the stability and efficiency of the process. A reversal process, the acidic chemical treatment of concrete waste (CW) to recycle its aggregates, generates calcium hydroxide, which can serve as buffering agent. Meanwhile, integrating both processes can introduce a sustainable win-win approach, which is the aim of this study. To assess this approach, a series of batch AF experiments were conducted at 50 °C and pH 5.5, using glucose as the substrate. Cementitious specimen (1.5 × 1.5 × 0.8 cm) was supplemented to each 200 mL-fermenter. Unamended fermenters, with and without additional NaHCO3-buffering, were used as controls to compare with the amended ones. Introducing cementitious specimens to AF increased H2-production by 2-fold and 1.7-fold compared to controls with and without NaHCO3-addition, respectively, after three consecutive feed-cycles. The surface analysis of incorporated specimen confirmed the Ca, Al, Mg, and Si leaching. The AF efficiency and resulting cementitious mass reduction were further assessed at different organic loads and specimens' volume, surface area, and porosity (by changing water-to-cement [W/C] ratio). Increasing the organic load from 10 to 20 g-glucose/L resulted in lower H2-production, higher specimen mass reduction (up to ∼32%), and higher Ca2+ release (up to 2 g/L); however, no significant effect was observed when using specimens with higher W/C ratio or surface area. Moreover, the presence of cementitious specimens significantly influenced the microbial composition, leading to notable developments in the abundant genera Thermoanaerobacterium and Bacillus. This study presents a novel approach to sustainably enhancing AF process using CW as both an additive and a treatable substance, with reusable aggregates as a byproduct. It provides valuable insights for optimizing the process and guiding future practical applications. This includes considering various concrete compositions, adjusting organic load conditions, and evaluating long-term stability in larger-scale systems.

2.
J Environ Sci (China) ; 139: 138-149, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38105042

RESUMO

Soil acidification is a major threat to agricultural sustainability in tropical and subtropical regions. Biodegradable and environmentally friendly materials, such as calcium lignosulfonate (CaLS), calcium poly(aspartic acid) (PASP-Ca), and calcium poly γ-glutamic acid (γ-PGA-Ca), are known to effectively ameliorate soil acidity. However, their effectiveness in inhibiting soil acidification has not been studied. This study aimed to evaluate the effect of CaLS, PASP-Ca, and γ-PGA-Ca on the resistance of soil toward acidification as directly and indirectly (i.e., via nitrification) caused by the application of HNO3 and urea, respectively. For comparison, Ca(OH)2 and lignin were used as the inorganic and organic controls, respectively. Among the materials, γ-PGA-Ca drove the substantial improvements in the pH buffering capacity (pHBC) of the soil and exhibited the greatest potential in inhibiting HNO3-induced soil acidification via protonation of carboxyl, complexing with Al3+, and cation exchange processes. Under acidification induced by urea, CaLS was the optimal one in inhibiting acidification and increasing exchangeable acidity during incubation. Furthermore, the sharp reduction in the population sizes of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) confirmed the inhibition of nitrification via CaLS application. Therefore, compared to improving soil pHBC, CaLS may play a more important role in suppressing indirect acidification. Overall, γ-PGA-Ca was superior to PASP-Ca and CaLS in enhancing the soil pHBC and the its resistance to acidification induced by HNO3 addition, whereas CaLS was the best at suppressing urea-driven soil acidification by inhibiting nitrification. In conclusion, these results provide a reference for inhibiting soil re-acidification in intensive agricultural systems.


Assuntos
Cálcio , Solo , Nitrificação , Amônia , Archaea , Ureia , Microbiologia do Solo , Concentração de Íons de Hidrogênio , Oxirredução
3.
Glob Chang Biol ; 29(13): 3692-3706, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37029763

RESUMO

Recent studies highlight the potential of climate change refugia (CCR) to support the persistence of biodiversity in regions that may otherwise become unsuitable with climate change. However, a key challenge in using CCR for climate resilient management lies in how CCR may intersect with existing forest management strategies, and subsequently influence how landscapes buffer species from negative impacts of warming climate. We address this challenge in temperate coastal forests of the Pacific Northwestern United States, where declines in the extent of late-successional forests have prompted efforts to restore old-growth forest structure. One common approach for doing so involves selectively thinning forest stands to enhance structural complexity. However, dense canopy is a key forest feature moderating understory microclimate and potentially buffering organisms from climate change impacts, raising the possibility that approaches for managing forests for old-growth structure may reduce the extent and number of CCR. We used remotely sensed vegetation indices to identify CCR in an experimental forest with control and thinned (restoration) treatments, and explored the influence of biophysical variables on buffering capacity. We found that remotely sensed vegetation indices commonly used to identify CCR were associated with understory temperature and plant community composition, and thus captured aspects of landscape buffering that might instill climate resilience and be of interest to management. We then examined the interaction between current restoration strategies and CCR, and found that selective thinning for promoting old-growth structure had only very minor, if any, effects on climatic buffering. In all, our study demonstrates that forest management approaches aimed at restoring old-growth structure through targeted thinning do not greatly decrease buffering capacity, despite a known link between dense canopy and CCR. More broadly, this study illustrates the value of using remote sensing approaches to identify CCR, facilitating the integration of climate change adaptation with other forest management approaches.


Assuntos
Mudança Climática , Refúgio de Vida Selvagem , Florestas , Biodiversidade , Plantas , Árvores
4.
J Environ Manage ; 338: 117833, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37004483

RESUMO

Increased riverine nitrogen (N) concentrations due to human activities is one of the leading causes of water quality decline, worldwide. Therefore, quantitative information about the N exported from watershed to the river (TN exports) is essential for defining N pollution control practices. This paper evaluated the changes in net anthropogenic N inputs (NANI) and the N stored in land ecosystems (legacy N) in the Jianghan Plain (JHP) from 1990 to 2019 and their impacts on TN exports. Moreover, an empirical model was developed to estimate TN exports, trace its source, and predict its future variations in 2020-2035 under different scenarios. According to the results, NANI exhibited a rise-decrease-rise-decrease M-shaped trend, with N fertilizer application being the dominant driver for NANI change. In terms of the NANI components, non-point-source was the primary N input form (96%). Noteworthy is that the correlation between NANI and TN exports became weaker over time, and large differences in changing trends were observed after 2014. A likely cause for this abnormal trend was that the accumulation of N surplus in soil led to N saturation in agricultural areas. Legacy N was also an important source of TN exports. However, the contribution of legacy N has rarely been considered when defining N pollution control strategies. An empirical model, incorporating legacy N, agricultural irrigation water use, and cropland area ratio, was developed. Based on this model, legacy N contributed a large proportion (15-31%). Furthermore, the results of future predictions indicated that legacy N had a larger impact on future TN exports changes compared to other factors, and increased irrigation water would increase rather than decrease TN exports. Therefore, an integrated N management strategy considering the impact of NANI, legacy N, and irrigation water use is crucial to control N pollution in areas with intensive agriculture.


Assuntos
Nitrogênio , Poluentes Químicos da Água , Humanos , Nitrogênio/análise , Monitoramento Ambiental , Ecossistema , Qualidade da Água , Agricultura , Rios , China , Poluentes Químicos da Água/análise , Fósforo/análise
5.
Molecules ; 28(21)2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37959842

RESUMO

Climate change is causing a significant decrease in the total acidity of grapes and related wines. This represents a serious issue for sparkling wine production. Consequently, before the second fermentation, the acidification of base wines is often necessary. However, the impacts of the most important organic acids on the foam properties of sparkling wines are not yet well known. The impacts of the addition of tartaric, malic, citric, and lactic acid on the quality of Falanghina and Bombino sparkling wines were evaluated. Analyses were performed soon after the second fermentation and one year after aging sur lees. The addition of each different organic acid to the two base wines resulted in significant changes in the sparkling wines not only in terms of pH, titratable acidity, and buffering capacity but also in the content of total amino acids and, in some cases, in the height of the foam and its stability over time. For both grape varieties, acidified wines showed a lower content of total amino acids in comparison with the control wines. The addition of lactic acid determined a higher persistency of the foam even after one year of aging sur lees only in Falanghina wines. The results obtained herein highlight the importance of organic acids and the pH of the base wines for the content of amino acids in sparkling wines. No strict correlation between organic acid addition and the foamability of wines was observed.


Assuntos
Vitis , Vinho , Vinho/análise , Vitis/química , Compostos Orgânicos , Aminoácidos/análise , Ácido Láctico
6.
Angew Chem Int Ed Engl ; 62(41): e202308335, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37604792

RESUMO

Performance of electrocatalytic reactions depends on not only the composition and structure of the active sites, but also their local environment, including the surrounding electrolyte. In this work, we demonstrate that BF2 (OH)2 - anion is the key fluoroborate species formed in the mixed KBi/KF (KBi=potassium borate) electrolyte to enhance the rate of the oxygen evolution reaction (OER) at near-neutral pH. Through a combination of electrokinetic and in situ spectroscopic studies, we show that the mixed KBi/KF electrolyte promotes the OER via two pathways: 1) stabilizing the interfacial pH during the proton-producing reaction with its high buffering capacity; and 2) activating the interfacial water via strong hydrogen bonds with F-containing species. With the KBi/KF electrolyte, electrodeposited Co(OH)2 is able to achieve 100 mA/cm2 at 1.74 V, which is among the highest reported activities with earth-abundant electrocatalysts at near neutral conditions. These findings highlight the potential of leveraging electrolyte-engineering for improving the electrochemical performance of the OER.

7.
Ecotoxicol Environ Saf ; 234: 113409, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35286955

RESUMO

Incubation experiments were conducted to investigate the influencing factors of pH variation in different paddy soils during submerging/draining alternation and the relationship between pH buffering capacity (pHBC) and Cd speciation in ten paddy soils developed from different parent materials (including 8 acid paddy soils and 2 alkaline paddy soils). The soil pHBC and the changes in soil pH, Eh, Fe2+, Mn2+, SO42- and Cd speciation were determined. The results showed that there was a significant positive correlation between cation exchange capacity (CEC) and pHBC of these paddy soils, indicating that soil CEC is a key factor affecting the pHBC of paddy soils. The contribution of Fe(III) oxide reduction to H+ consumption is far greater than the reduction of Mn(IV)/Mn(III) oxides and SO42- during the submerging. For example, the contribution of the reduction of manganese oxides, SO42- and iron oxides to H+ consumption in the paddy soils from Anthrosol at 15 d submerging was 1.2%, 11.6% and 87.2%, respectively. This confirms that the reduction of Fe(III) oxides plays a leading role in increasing soil pH. Importantly, we noticed that during submerging, soil pH was increased and resulted in the content of available Cd in soils being reduced. This was due to the transformation of Cd to less active forms. Also, there was a significant positive correlation between the change rate of available Cd, the percentage of acid extractable Cd and pH variation. This suggests that the variation in soil pH was responsible for the transformation of Cd speciation. In addition, the change rate of available Cd and the percentage of acid extractable Cd concentration were significantly negatively correlated with soil pHBC. The soil with higher pHBC experienced less pH change, and thus the change rate of available Cd and the percentage of acid extractable Cd concentration were less for the soil. The results of this study can provide a basis for the remediation of Cd-contaminated acidic paddy soils.

8.
J Environ Manage ; 322: 116144, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36067661

RESUMO

Acid rain is a global environmental problem that mobilizes heavy metals in soils, while the distribution and geochemical fraction of heavy metals during acid rain infiltration in heterogeneous soils are still unclear. In this study, we performed column experiments to investigate the distribution and geochemical fraction of Cu, Pb, Ni and Cd in heterogeneously layered soils during continuous acid rain infiltration. Chloride ion used as a conservative tracer was found to be uniformly distributed during acid rain infiltration, showing insignificant preferential flow effects in the column. In contrast, however, the distribution of heavy metals was highly non-uniform, especially in the silty soil at the lower part of the column, indicating a heterogeneous distribution of adsorption capacity. In addition, in the control experiments with neutral rain infiltration, uniform distribution of heavy metals was observed, indicating that the heterogeneous distribution of adsorption coefficient during acid rain infiltration was mainly caused by different pH buffering capacities. A numerical model considering water flow and solute transport was developed, where the average water-solid distribution coefficient (Kd) in Layer 2 was only 1.5-12.5% of that in Layer 1 during acid rain infiltration. The model could predict the variation of heavy metal concentrations in soil with the majority of error less than 35%, confirming that different Kd induced the heterogeneous distribution of heavy metals. In addition, the geochemical fraction of heavy metals in the upper coarse sand layer remained stable, while the acid-extractable fractions in the lower loam and silt loam layer gradually increased. Our findings suggest that soil heterogeneity, especially chemical heterogeneity affected by rainfall acidity, has an important influence on the infiltration, migration and geochemical fraction of heavy metals in soils. This study could help guide the risk assessment of heavy metal-contaminated sites that were polluted by acid rain or landfill leachate.


Assuntos
Chuva Ácida , Metais Pesados , Poluentes do Solo , Poluentes Químicos da Água , Cádmio , China , Cloretos , Monitoramento Ambiental , Chumbo , Metais Pesados/análise , Areia , Solo , Poluentes do Solo/análise , Água
9.
J Environ Manage ; 315: 115164, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35500489

RESUMO

The catchment phosphorus buffering capacity (PBF) determines the pressure-state-response relationship between anthropogenic P inputs and aquatic ecosystems at a catchment scale, and is affected by biogeochemical, hydrological, and ecological catchment characteristics. However, the complex relationship between these catchment characteristic factors and their impact pathways on PBF remains ambiguous, leading to large uncertainty in balancing agricultural productivity and water conservation via improving BF through management practices. In this study, the short-term buffering index, calculated from net anthropogenic P input and riverine P exports, was used to quantify the spatiotemporal variations in PBF in source agricultural catchments in the Dongting Lake basin. Partial least squares structural equation modeling was used to investigate the relationship between the PBF and the catchment characteristics. The results indicate that catchment PBF was directly determined by soil properties and hydrological conditions, while landscape patterns significantly mediated the effects of topography on soil and hydrology. Considering the pathway preferences of the model, landscape patterns could be the priority for characterizing and regulating PBF. According to a change-point analysis, the probability of PBF weakening increases dramatically when the proportion of farmland (Farm%) > 24.6%, degree of patch interspersion (Contagion index) < 64.5%, and Perimeter-Area Ratio Distribution (PARA) > 348.7. These findings provide new insights into catchment buffering mechanisms and can be used to promote the simultaneous achievement of agricultural production and environmental conservation goals.


Assuntos
Hidrologia , Fósforo , China , Ecossistema , Monitoramento Ambiental , Fósforo/análise , Rios/química , Solo/química
10.
Clin Oral Investig ; 25(4): 1815-1827, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32779011

RESUMO

OBJECTIVE: To evaluate the efficacy of an edible artificial saliva gel, oral moisturizing jelly (OMJ), and a topical commercial gel (GC dry mouth gel) on Candida colonization and saliva properties. MATERIALS AND METHODS: This study was a secondary analysis of a single-blinded randomized controlled trial conducted in xerostomic post-radiotherapy head and neck cancer patients. Candida colonization, stimulated salivary flow rate (SSFR), saliva pH, and buffering capacity (BC) were measured at 0, 1, and 2 months after each intervention. Candida colonization was quantified by colony counts and species identified by Candida Chromagar, polymerase chain reaction, and API 20C AUX system. Statistical significance level was 0.05. RESULTS: A total of 56 participants in OMJ (N = 30) and GC (N = 26) groups completed the study. OMJ significantly increased saliva pH (p = 0.042) and BC (p = 0.013) after 1-month use, while GC only improved saliva pH (p = 0.027). Both interventions tended to increase SSFR but only GC had a significant increase at 2 months (p = 0.015). GC and OMJ significantly decreased the number of Candida species at 1 and 2 months, respectively. Both groups tended to reduce Candida counts but not significant. CONCLUSIONS: Both OMJ and GC saliva gels could improve saliva pH and decrease the number of Candida species. OMJ is superior to GC in its buffering capacity, while GC may better improve salivary flow rate. Long-term and large-scale study is warranted to test the efficacy of artificial saliva in oral health improvement. CLINICAL RELEVANCE: OMJ and GC gel could decrease the number of Candida species and improve saliva properties in post-radiation xerostomic patients. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov NCT03035825. Date of registration: 25th January 2017.


Assuntos
Neoplasias de Cabeça e Pescoço , Xerostomia , Candida , Géis , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Saliva , Saliva Artificial , Xerostomia/etiologia
11.
Cleft Palate Craniofac J ; 58(9): 1150-1159, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33349037

RESUMO

OBJECTIVE: The aim of the study was to analyze the caries protective factors, salivary parameters, and microbial counts in high caries risk children with cleft lip and/or palate (CL/P). DESIGN: This was a cross-sectional study. SETTING: This study was conducted in a tertiary health care teaching hospital in New Delhi, India. PARTICIPANTS: The study was conducted in 40 children, 20 with CL/P and 20 without aged between 5 and 12 years. METHODS: Children with 2 or more caries lesions in both groups were included in this study. Demographic details, dental caries of affected teeth (World Health Organization criteria for Decayed Missing Filled Teeth [WHO-DMFT] and International Caries Detection and Assessment System [ICDAS II]), caries protective factors, salivary parameters, and microbial counts were recorded by one calibrated investigator. MAIN OUTCOME MEASURES: Caries protective factors, salivary parameters, and microbial profile. RESULTS: The Chi-square (χ2) test and Pearson correlation were used for statistical analysis. All the children participating in the study brushed their teeth only once in a day and consumed sweets more than twice a day. None of the children had ever received fluoride varnish. Resting saliva had a low buffering capacity in 80% of children with CL/P and 95% of children without CL/P. Microbial assessment of stimulated saliva showed that with the increases in the numbers (DMFT scores ≥4) and severity (ICDAS codes from 1-2 to 5-6) of caries lesions, both Streptococci and Lactobacilli counts were ≥105 colony-forming units/mL of saliva in the both groups. CONCLUSIONS: Children with CL/P showed limited access to caries protective measures and low buffering capacity in resting saliva, along with elevated levels of salivary Streptococci and Lactobacilli in stimulated saliva.


Assuntos
Fenda Labial , Fissura Palatina , Cárie Dentária , Criança , Pré-Escolar , Fenda Labial/epidemiologia , Fissura Palatina/epidemiologia , Estudos Transversais , Índice CPO , Cárie Dentária/epidemiologia , Suscetibilidade à Cárie Dentária , Humanos , Saliva , Streptococcus mutans
12.
BMC Oral Health ; 21(1): 47, 2021 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-33541321

RESUMO

BACKGROUND: There is little knowledge about factors which may affect oral health among older adults. The objective of this study was to determine the relationship between Streptococcus mutans (MS) and Lactobacilli (LB) counts and caries among older adults. METHODS: In this community-based observation study, 141 participants aged 60 years and above were recruited from the west district of Singapore. Alongside the clinical examination, saliva samples were collected to determine Streptococcus mutans (MS) and Lactobacilli (LB) counts, as well as to record salivary flow rate and buffering capacity of saliva. RESULTS: Of the 141 participants, 63.8% were female and 94.3% were of Chinese ethnicity. The mean DMFT was 11.08 (s.d. 8.27). 9.9% of participants had at least one decayed tooth, 52.5% had minimum one missing tooth and 86.5% had at least one filled tooth. 67.4% had MS counts of ≥ 105 while LB counts were ≥ 105 for 48.2%. 83.7% had normal salivary flow or hypersalivation (> = 1 mL/min), the buffering capacity of the saliva was alkaline in 61% of the participants. Multivariate analysis showed that participants who had high MS counts were less likely to have a DMFT < 12 [OR (95% CI), 0.29 (0.11-0.77)] whereas participants who had high LB counts were less likely to have a DMFT ≤ 14 [OR (95% CI), 0.45 (0.20-1.002)]. CONCLUSION: Our study showed a positive correlation between MS and LB counts and caries experience in older adults. The mean DMFT was on the low side in our sample despite having a relatively high MS count. This suggests that there are many other factors which vary according to host environment, physiological and biological conditions that may affect MS and LB counts in the oral cavity. CLINICAL RELEVANCE: Our study supports the knowledge that the aetiology of dental caries among older adults is a complex process and it would be wrong to consider caries as a same problem with the same solution for all age groups.


Assuntos
Suscetibilidade à Cárie Dentária , Cárie Dentária , Idoso , Contagem de Colônia Microbiana , Índice CPO , Cárie Dentária/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saliva , Streptococcus mutans
13.
BMC Microbiol ; 19(1): 222, 2019 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-31606047

RESUMO

BACKGROUND: Liberibacter crescens is the closest cultured relative of four important uncultured crop pathogens. Candidatus. L. asiaticus, L. americanus, L. africanus cause citrus greening disease, while Ca. L. solanacearum causes potato Zebra chip disease. None of the pathogens grows in axenic culture. L. crescens grows in three media: a BM-7, a serum-free Hi® Grace's Insect Medium (Hi-GI), and a chemically-defined medium called M15. To date, no optimal growth parameters of the model species L. crescens have been reported. Studying the main growth parameters of L. crescens in axenic culture will give us insights into the lifestyle of the Ca. Liberibacter pathogens. RESULTS: The evaluation of the growth parameters-pH, aeration, temperature, and buffering capacity-reflects the optimal living conditions of L. crescens. These variables revealed that L. crescens is an aerobic, neutrophilic bacterium, that grows optimally in broth in a pH range of 5.8 to 6.8, in a fully oxygenated environment (250 rpm), at 28 °C, and with monosodium phosphate (10 mM or 11.69 mM) as the preferred buffer for growth. The increase of pH in the external media likely results from the deamination activity within the cell, with the concomitant over-production of ammonium in the external medium. CONCLUSION: L. crescens and the Ca. Liberibacter pathogens are metabolically similar and grow in similar environments-the phloem and the gut of their insect vectors. The evaluation of the growth parameters of L. crescens reveals the lifestyle of Liberibacter, elucidating ammonium and phosphate as essential molecules for colonization within the hosts. Ammonium is the main driver of pH modulation by active deamination of amino acids in the L. crescens amino acid rich media. In plants, excess ammonium induces ionic imbalances, oxidative stress, and pH disturbances across cell membranes, causing stunted root and shoot growth and chlorosis-the common symptoms of HLB-disease. Phosphate, which is also present in Ca. L. asiaticus hosts, is the preferred buffer for the growth of L. crescens. The interplay between ammonium, sucrose, potassium (K+), phosphate, nitrate (NO3-), light and other photosynthates might lead to develop better strategies for disease management.


Assuntos
Compostos de Amônio/metabolismo , Técnicas Bacteriológicas/métodos , Produtos Agrícolas/microbiologia , Fosfatos/metabolismo , Rhizobiaceae/crescimento & desenvolvimento , Animais , Meios de Cultura/química , Interações entre Hospedeiro e Microrganismos , Concentração de Íons de Hidrogênio , Insetos Vetores/microbiologia , Liberibacter , Floema/microbiologia , Rhizobiaceae/metabolismo , Temperatura
14.
Amino Acids ; 51(1): 49-60, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30003336

RESUMO

ß-alanine supplementation increases muscle carnosine content and improves anaerobic exercise performance by enhancing intracellular buffering capacity. ß-alanine ingestion in its traditional rapid-release formulation (RR) is associated with the symptoms of paresthesia. A sustained-release formulation (SR) of ß-alanine has been shown to circumvent paresthesia and extend the period of supply to muscle for carnosine synthesis. The purpose of this investigation was to compare 28 days of SR and RR formulations of ß-alanine (6 g day-1) on changes in carnosine content of the vastus lateralis and muscle fatigue. Thirty-nine recreationally active men and women were assigned to one of the three groups: SR, RR, or placebo (PLA). Participants supplementing with SR and RR formulations increased muscle carnosine content by 50.1% (3.87 mmol kg-1ww) and 37.9% (2.62 mmol kg-1ww), respectively. The change in muscle carnosine content in participants consuming SR was significantly different (p = 0.010) from those consuming PLA, but no significant difference was noted between RR and PLA (p = 0.077). Although participants ingesting SR experienced a 16.4% greater increase in muscle carnosine than RR, fatigue during maximal voluntary isometric contractions was significantly attenuated in both SR and RR compared to PLA (p = 0.002 and 0.024, respectively). Symptoms of paresthesia were significantly more frequent in RR compared to SR, the latter of which did not differ from PLA. Results of this study demonstrated that only participants consuming the SR formulation experienced a significant increase in muscle carnosine. Differences in the muscle carnosine response between these formulations may have practical significance for athletic populations in which small changes may have important implications on performance.


Assuntos
Carnosina/biossíntese , Preparações de Ação Retardada/administração & dosagem , Suplementos Nutricionais , Músculo Esquelético/efeitos dos fármacos , Parestesia/prevenção & controle , beta-Alanina/administração & dosagem , Adulto , Carnosina/agonistas , Método Duplo-Cego , Esquema de Medicação , Exercício Físico , Feminino , Humanos , Contração Isométrica/efeitos dos fármacos , Masculino , Fadiga Muscular/efeitos dos fármacos , Fadiga Muscular/fisiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Parestesia/metabolismo , Parestesia/fisiopatologia
15.
Bioessays ; 39(5)2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28383767

RESUMO

Accumulation of neurotransmitters in the lumen of synaptic vesicles (SVs) relies on the activity of the vacuolar-type H+ -ATPase. This pump drives protons into the lumen, generating a proton electrochemical gradient (ΔµH+ ) across the membrane. Recent work has demonstrated that the balance between the chemical (ΔpH) and electrical (ΔΨ) components of ΔµH+ is regulated differently by some distinct vesicle types. As different neurotransmitter transporters use ΔpH and ΔΨ with different relative efficiencies, regulation of this gradient balance has the potential to influence neurotransmitter uptake. Nevertheless, the underlying mechanisms responsible for this regulation remain poorly understood. In this review, we provide an overview of current neurotransmitter uptake models, with a particular emphasis on the distinct roles of the electrical and chemical gradients and current hypotheses for regulatory mechanisms.


Assuntos
Neurotransmissores/metabolismo , Bombas de Próton/metabolismo , Animais , Transporte Biológico Ativo , Eletroquímica , Ácido Glutâmico/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Potenciais da Membrana , Modelos Neurológicos , Prótons , Vesículas Sinápticas/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismo
16.
J Sci Food Agric ; 99(8): 3895-3902, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30684273

RESUMO

BACKGROUND: The aim of the study was to rank conventionally used fibre rich feeds for their physicochemical properties and detect possible correlation between analytical fibre determinations. A total of 22 samples were analysed for proximate fibre values, soluble dietary fibre (SDF), insoluble dietary fibre (IDF), crude protein (CP) and crude ash (CA). Physicochemical properties were determined in vitro by hydration capacity (HC) [water holding capacity (WHC), water binding capacity (WBC), swelling property (SwP)] and buffering capacity [linear buffering rate (LBR)]. RESULTS: Fibre content and physicochemical properties varied markedly between the samples. HC was highest for beet pulp and lowest for rice and millet bran. Buffering capacity expressed minimum values for lignocelluloses and maximum values for rape seed hulls. The correlation of methods was positively between WBC, WHC and SwP (r ≤ 0.89; P ≤ 0.003) but not significant for HC and buffering capacity. SwP negatively correlated with crude fibre (CF), neutral detergent fibre (aNDFOM ) and IDF (r ≤ -0.48; P ≤ 0.05). WBC and SwP positively correlated with SDF (r ≤ 0.63; P ≤ 0.04). LBR was negatively correlated with CF, aNDFOM , IDF and total dietary fibre (r ≤ -0.55; P ≤ 0.02), but positively with CP (r = 0.53; P = 0.01). CONCLUSION: The determination of physicochemical properties is applicable to rank fibre rich feeds, some correlations between fibre analytical measurements and physicochemical properties were detected. © 2019 Society of Chemical Industry.


Assuntos
Ração Animal/análise , Fibras na Dieta/análise , Preparações de Plantas/química , Fenômenos Fisiológicos da Nutrição Animal , Animais , Fenômenos Químicos , Fibras na Dieta/metabolismo , Plantas/química , Água/química
17.
J Contemp Dent Pract ; 20(8): 920-927, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31797848

RESUMO

AIM: The present study was conducted to compare the efficacy of all Punica granatum, Terminalia chebula, and Vitis vinifera on salivary Streptococcus mutans levels in children and also to evaluate their substantivity at an interval of 15 days that is at day 1, days 16, and 31. MATERIALS AND METHODS: This study was designed for a randomized clinical double-blinded study where 80 children of 8-15 years of age were living in a residential premise. Subjects were randomly divided into 4 groups of 20 each to whom mouthrinses were given. The criteria for assessing the efficacy was done by collecting the saliva sample for pH, buffering capacity, plaque index, and Streptococcus mutans microbiologic assay. These values were assessed at the baseline, days 16, and 31. Children were asked to discontinue mouthrinse from days 16 to 31. The supervisor was trained to administer the mouthrinses properly. RESULTS: The data were coded and analysis was done using the SPSS version 20. The level of significance was set at p < 0.05. The pH and buffering capacity showed that values were almost the same among all four groups at various time intervals which showed statistically nonsignificant results. Punica granatum showed a maximum reduction in S. mutans count followed by T. chebula and V. vinifera, although they were statistically nonsignificant. The Vitis vinifera group had successfully reduced more plaque score at day 16 (0.04) followed by T. chebula (0.09) and P. granatum (0.12). CONCLUSION: This in vivo study implied that V. vinifera had shown the lowest plaque reduction owing to its antioxidant and phytochemical properties. And P. granatum showed the maximum substantivity. CLINICAL SIGNIFICANCE: Mouthrinses helped in reducing plaque deposition, caries activity, and helped in oral hygiene maintenance. Hereby, we can conclude that nutraceutical mouthrinses are safe in children and produced superior results than the chemical mouthrinses.


Assuntos
Antissépticos Bucais , Extratos Vegetais , Streptococcus mutans , Terminalia , Adolescente , Criança , Humanos , Extratos Vegetais/uso terapêutico , Punica granatum , Saliva , Sementes , Streptococcus mutans/efeitos dos fármacos , Vitis
18.
Niger J Clin Pract ; 22(5): 707-712, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31089027

RESUMO

OBJECTIVE: Orthodontic treatment using fixed appliances is known to alter the oral environment and encourage plaque retention around orthodontic brackets and bands, resulting in enamel demineralization and gingival inflammation. This study aimed to evaluate the changes in essential salivary parameters in patients undergoing fixed orthodontic treatment. MATERIALS AND METHODS: Saliva samples were collected from 60 patients before and 2 months after commencing fixed orthodontic treatment. The salivary flow rate, pH, buffering capacity, and levels of amylase, total protein, and glucose were determined. Parametric and nonparametric tests for paired samples were used for comparing the mean differences before and after commencing treatment. RESULTS: Significant reductions in the salivary flow rate, pH, and buffering capacity were noted 2 months after commencing treatment (P < 0.05). Total protein concentrations and calcium levels decreased significantly and amylase and glucose levels increased after commencing treatment (P < 0.05). Significant correlations were observed between salivary total protein concentrations and buffering capacity as well as calcium levels (P < 0.05). CONCLUSION: These findings indicate that the biochemical properties of saliva are altered after introducing fixed orthodontic appliances into the oral cavity, thereby promoting plaque retention and increasing the susceptibility to tooth demineralization and gingival inflammation.


Assuntos
Amilases/análise , Glucose/análise , Aparelhos Ortodônticos Fixos , Proteínas/análise , Saliva/química , Salivação , Adolescente , Adulto , Humanos , Concentração de Íons de Hidrogênio , Estudos Longitudinais , Adulto Jovem
19.
J Exp Biol ; 221(Pt 10)2018 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-29650754

RESUMO

Muscle pH decreases during exercise, which may impair function. Endurance training typically reduces muscle buffering capacity as a result of changes in fiber-type composition, but existing comparisons of species that vary in activity level are ambiguous. We hypothesized that high-runner (HR) lines of mice from an experiment that breeds mice for voluntary wheel running would have altered muscle buffering capacity as compared with their non-selected control counterparts. We also expected that 6 days of wheel access, as used in the selection protocol, would reduce buffering capacity, especially for HR mice. Finally, we expected a subset of HR mice with the 'mini-muscle' phenotype to have relatively low buffering capacity as a result of fewer type IIb fibers. We tested non-bicarbonate buffering capacity of thigh muscles. Only HR mice expressing the mini-muscle phenotype had significantly reduced buffering capacity, females had lower buffering capacity than males, and wheel access had no significant effect.


Assuntos
Atividade Motora/fisiologia , Músculo Esquelético/metabolismo , Corrida/fisiologia , Animais , Feminino , Concentração de Íons de Hidrogênio , Masculino , Camundongos , Fibras Musculares Esqueléticas/química , Fibras Musculares Esqueléticas/metabolismo , Fenótipo , Condicionamento Físico Animal/fisiologia
20.
Food Microbiol ; 73: 245-253, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29526209

RESUMO

Understanding lactic acid bacteria (LAB) fermentation behavior in malt wort is a milestone towards flavor improvement of lactic acid fermented malt beverages. Therefore, this study aims to outline deficiencies that may exist in malt wort fermentation. First, based on six LAB strains, cell viability and vitality were evaluated. Second, sugars, organic acids, amino acids, pH value and buffering capacity (BC) were monitored. Finally, the implication of key amino acids, fructose and wort BC on LAB growth was determined. Short growth phase coupled with prompt cell death and a decrease in metabolic activity was observed. Low wort BC caused rapid pH drop with lactic acid accumulation, which conversely increased the BC leading to less pH change at late-stage fermentation. Lactic acid content (≤3.9 g/L) was higher than the reported inhibitory concentration (1.8 g/L). Furthermore, sugars were still available but fructose and key amino acids lysine, arginine and glutamic acid were considerably exhausted (≤98%). Wort supplementations improved cell growth and viability leading to conclude that key amino acid depletion coupled with low BC limits LAB growth in malt wort. Then, a further increase in organic acid reduces LAB viability. This knowledge opens doors for LAB fermentation process optimization in malt wort.


Assuntos
Aminoácidos/metabolismo , Hordeum/microbiologia , Lactobacillales/metabolismo , Aminoácidos/análise , Bebidas/análise , Bebidas/microbiologia , Soluções Tampão , Fermentação , Hordeum/química , Concentração de Íons de Hidrogênio , Ácido Láctico/análise , Ácido Láctico/metabolismo
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