Low pH Values Research Articles

Characterization and mid-term outcomes of current out-of-hospital cardiac arrest patients admitted to intensive cardiovascular care units

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Consell Català de Resuscitació. Background Out-of-hospital cardiac arrest (OHCA) accounts the 50% of cardiovascular deaths. Being aware of characteristics and outcomes of our OHCA population is important in order to apply measures in the weaker areas to improve the results of the process. Purpose To investigate current outcomes, at 6-month follow-up, of patients admitted to an Intensive Cardiac Care Unit (ICCU) in a mediterranean area during the 2020s. Current characteristics, prehospital management and factors related to outcomes were also analyzed. Methods PCR-Cat was a prospective observational multicentre registry. OHCA patients admitted to the ICCU of 8 hospitals were included from October/2020 to December/2021. Those who survived with good neurological status, no disabilities, and remained independent for usual life activities, were classified as Good Outcome (GO). Those patients who died or had a poor neurological status, with high dependency or rested in permanent vegetative status were classified as Poor Outcome (PO). A multinomial logistic regression was done to analyze the factors independently related to PO. Results 288 patients were included, only 50 (17.36%) were women. At 6-month follow-up, 48.95% of patients had GO. Most events happened in the first month (Figure 1). The cause of death was neurological in 72.9%. Patients with PO were significantly older (63.74 vs. 58.88, p=0.003) and had more comorbidities (Table 1A). The most frequent location was on a public space (54.84%) and most were witnessed (88.93%). Cardiopulmonary resuscitation maneuvers were initiated by a bystander in 69.18% until EMS arrival, being only 20.79% done by an experienced bystander. The medium no-flow time was low (2 min) but total time until ROSC was of 28 min. First rhythm was shockable in 80%, but an automatic external defibrillator was only used in 58% of cases. Statistically significant lower values of first pH and higher values of first lactate, glucose and creatinine were related to PO (Table 1B). Patients with PO had a higher APACHE II (26 vs. 20, p<0.001) and SOFA (10.39 vs. 7.14, p<0.001) scores at admission, and required a longer time on mechanical ventilation (6 vs. 3.5 days, p=0.001). The main cause of the OHCA was acute coronary syndrome (53.82%), followed by chronic coronary syndrome (7.64%) and dilated myocardiopathy (7.64%). In the multinomial logistic regression, older age (p=0.005), male sex (p=0.016), previous stroke (p=0.046), longer ROSC time (p<0.001) and non-shockable first rhythm (p<0.001) were independently related to PO. Receiving cardiopulmonary resuscitation maneuvers by an experienced bystander was related to a reduction of 17 min of ROSC (p=0.001). Conclusions Less than a half of patients admitted to an ICCU because of an OHCA had GO at 6-month follow-up. Age, male sex, previous stroke, longer ROSC time and non-shockable first rhythm were factors independently related to PO. Interventions addressed to reduce ROSC time are urgently needed.

On improved microstructure properties of slag-based UHPC incorporating calcium formate and calcium chloride

The study aimed to achieve high strength in slag-based cementless ultra-high performance concrete (UHPC) while investigating the role of calcium formate and calcium chloride as accelerators using advanced characterization and microstructural analysis. The UHPC specimens were evaluated using various techniques, including heat of hydration, thermogravimetric analysis, X-ray diffraction, nuclear magnetic resonance, scanning electron microscopy, and porosity measurements. The results showed that both accelerators improved the UHPC properties, with calcium formate being more effective than calcium chloride, as evidenced by higher heat of hydration, improved microstructure, and lower porosity. Furthermore, the thermodynamic modeling revealed insightful information on the reaction mechanisms with C-(N-)A-S-H and hydrotalcite as the primary hydration products formed in the matrix. Notably, the UHPC specimens with calcium chloride exhibited a very low pH value, which could increase the risk of corrosion in reinforced structures. Therefore, the use of calcium formate as an accelerator can lead to the development of cementless UHPC with superior properties.

Pipeline corrosion prediction and uncertainty analysis with an ensemble Bayesian neural network approach

This study developed an ensemble Bayesian Neural Network (BNN) model for pipeline corrosion prediction incorporating uncertainty analysis. The performance of the proposed BNN model was compared with different empirical and data-driven models. Shapley Additive Explanation (SHAP) values were used to quantify the importance of input factors. Results indicate that the ensemble BNN model demonstrates superior prediction accuracy, achieving the highest R2 value of 0.949, with the lowest Mean Absolute Error (MAE) of 0.33 mm and Root Mean Square Error (RMSE) of 0.449 mm on corrosion depth. It outperforms other models in predicting maximum corrosion depth and uniquely captures uncertainty information, which deterministic models cannot provide. Key factors influencing corrosion include chloride content, pH, pipe-to-soil potential, and pipeline age. Specifically, conditions such as a pipe-to-soil potential exceeding − 0.85 V, a pipeline age over 20 years, and pH values below 7 are found to significantly accelerate corrosion. The model also illustrates the effects of different influencing factors on corrosion growth uncertainty. Higher chloride content, lower pH values, and higher pipe-to-soil potentials may expand the uncertainty bounds. The proposed model presents the dynamic changes in prediction uncertainty over time, which is usually ignored in previous models. It can improve the precision and reliability of long-term predictions concerning pipeline corrosion depth. This knowledge of corrosion uncertainty is crucial for making informed decisions about pipeline inspection and maintenance strategies.

Lactate Levels as a Predictor of Emergency Department Revisits in Infants With Acute Bronchiolitis.

This study aimed to identify predictive biomarkers for unscheduled emergency department (ED) revisits within 24 hours of discharge in infants diagnosed with acute bronchiolitis (AB). A retrospective observational study was conducted on infants diagnosed with AB who visited 3 emergency medical centers between January 2020 and December 2022. The study excluded infants with comorbidities, congenital diseases, and prematurity and infants who revisited the ED after 24 hours of discharge. Demographic data, vital signs, and laboratory results were collected from the medical records. Univariable and multivariable logistic regression analyses were performed on factors with P of less than 0.1 in univariable analysis. Receiver operator curve analysis was used to assess the accuracy of lactate measurements in predicting ED revisits within 24 hours of discharge. Out of 172 participants, 100 were in the revisit group and 72 in the discharge group. The revisit group was significantly younger and exhibited higher lactate levels, lower pH values, and higher pCO 2 levels compared to the discharge group. Univariable logistic regression identified several factors associated with revisits. Multivariable analysis found that only lactate was a variable correlated with predicting ED revisits (odds ratio, 18.020; 95% confidence interval [CI], 5.764-56.334). The receiver operator curve analysis showed an area under the curve of 0.856, with an optimal lactate cutoff value of 2.15. Lactate value in infants diagnosed with AB were identified as a potential indicator of predicting unscheduled ED revisits within 24 hours of discharge. The predictive potential of lactate levels holds promise for enhancing prognosis prediction, reducing health care costs, and alleviating ED overcrowding. However, given the study's limitations, a more comprehensive prospective investigation is recommended to validate these findings.

Maternal and Neonatal Characteristics Associated With Failed Induction of Labor in Diabetic Mothers [ID 2683497

INTRODUCTION: Uncontrolled diabetes is a risk factor for cesarean delivery. Identifying and stratifying associated risk factors for failed induction of labor (IOL) may improve counseling and intrapartum care. This study aims at determining maternal and fetal factors that would predict the occurrence of failed IOL in diabetic mothers. METHODS: This is a retrospective study of 2,172 diabetic mothers who underwent IOL at a single university medical center between January 2013 and December 2021. Maternal and neonatal characteristics were obtained. Among the studied maternal characteristics were ethnicity, age, gestational age, medical comorbidities (including preeclampsia and essential hypertension), insulin administration, parity, and health insurance type (public versus private). Statistical analysis was performed using univariate and multivariate logistic regression. A value of P<.05 was considered statistically significant. RESULTS: Our preliminary analysis showed that 567 out of 2,172 (26.1%) diabetic mothers failed IOL and delivered via cesarean pathway. Failed IOL was associated with nulliparity (P=.0001), preexisting diabetes (compared to gestational diabetes) (P=.001), control of diabetes by insulin (P=.001), maternal essential hypertension (P=.001), preeclampsia (P=.001), polyhydramnios (P=.001), prenatal diagnosis of fetal growth restriction (P=.008), and placental abnormalities (P=.027). Neonatal weight, large for gestational age, head circumference, and height were not statistically associated with failed induction of labor (all values of P>.05). Failed IOL was associated with admission to neonatal intensive care unit (P=.001), hyperbilirubinemia (P=.001), lower APGAR score at 1 minute (P=.033), longer stay in the hospital (0.001). Failed IOL was not associated with lower APGAR score at 5 minutes, lower umbilical cord pH value, neonatal readmission or maternal ethnicity (all values of P>.05). CONCLUSION: Failed IOL among diabetic mothers is associated with significant maternal and neonatal adverse outcomes. Our continued data analysis aims at assessing the role of optimal glucose control and other maternal factors in improving maternal and neonatal outcomes.

The Potency of Inulin Extract from Mangrove Apple as a Prebiotic for Lactobacillus bulgaricus Growth In Vitro

Prebiotic sources can be developed from natural materials such as the inulin of mangrove apples (IMA). The objective of this research was to evaluate the efficacy of inulin from mangrove apples on the growth of Lactobacillus bulgaricus at an incubation time of 24 h. The experiment was conducted in the completely randomized design with 4 replicates using five different concentrations of IMA. The IMA concentrations applied in this study were 0, 2.5, 5.0, 7.5 and 10% w/v. The concentration of IMA of 10% had significantly (P<0.05) revealed to have higher viability of L. bulgaricus bacteria, presenting the growth value of 9.63±0.61 log CFU/mL, producing 1.55±0.02% of total lactic acid and resulting the low pH value at 3.46±0.01. L. bulgaricus could produce different amounts of short-chain fatty acid content In vitro. IMA could be a candidate as prebiotics to support the survival of L. bulgaricus. © 2024 Friends Science Publishers

Comprehensive Studies of Adsorption Equilibrium and Kinetics for Selected Aromatic Organic Compounds on Activated Carbon.

This work presents a comprehensive analysis of the adsorption of selected aromatic organic compounds on activated carbons. Both the equilibrium and kinetics of adsorption were studied using UV-Vis spectrophotometry. The influence of a number of factors: pH, contact time, presence of an accompanying substance, adsorbate concentration, as well as the mass and size of adsorbent grains, on the adsorption process from aqueous solutions was investigated. Phenol, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol and methylene blue (as an accompanying substance) were selected as adsorbates. GAC 1240W and RIAA activated carbons were used as adsorbents. The equilibrium data were analyzed using the generalized Langmuir isotherm equation (R2 = 0.912-0.996). Adsorption rate data were fitted using a multi-exponential kinetic equation (1 - R2 = (1.0 × 10-6)-(8.2 × 10-4)). As an additional parameter, the half-time was also used to present the influence of selected factors on the adsorption kinetics. An increase in the amount of adsorption was demonstrated with increasing contact time as well as with decreasing solution pH and adsorbent grain size. For selected systems, an increase in the adsorption rate was observed with increasing adsorbate concentration, adsorbent mass and at lower pH values. In some cases, the presence of an accompanying substance also resulted in an increase in adsorption kinetics. In the tested experimental systems, optimal conditions for adsorption were established (T = 298 K, pH = 2, contact time: 7 days, grain diameter: >0.5 mm and the ratio of the mass of the adsorbent to the volume of the adsorbate solution: 1 g/L). Additionally, the acid-base properties (potentiometric titration), morphology (SEM) and structure (TEM) of the used adsorbents were also examined.

A film composed of PEDOT:PSS/PVA as a sensitive medium for pH sensor in optical fiber

In this work, a pH sensitive transducer element attached to a multimode optical fiber section is proposed. The sensitive element is a PEDOT:PSS/PVA composite film that exhibited sensitivity at low pH values in the range of 1–7 pH. The addition of PVA was important for the adhesion process to the optical fiber surface. The morphology of the PEDOT:PSS polymers allowed characterization at pH stimuli that were based on the optical power transmission generated from the interaction of the light propagating in the optical fiber core and the optical fiber section coated with the sensitive film. A sensitivity of −0.05 dB/pH and a linear fit R2 of 0.93 was obtained, the response time was 3 s, while the sensor recovery time was 50 s maintaining stability higher than 10 min.

Retardation mechanism of phosphogypsum in phosphogypsum-based excess-sulfate cement

The effect of phosphogypsum (PG) on the hydration and retardation mechanism of phosphogypsum-based excess-sulfate slag cement (PESC) was mainly investigated. Based on the natural characteristics of PG, such as low pH value and the presence of soluble phosphorus impurities, the content of PG passing the 4.75 mm standard sieve was used as a variable to study the retardation mechanism of PG on PESC. It can be inferred from the heat flow and cumulative heat flow that the induction period is significantly prolonged with the content of PG, which is also reflected in the increase of the setting time of PESC. In the early period of hydration, as the content of PG increases, the soluble phosphorus concentration increases, and the pH value decreases. The changes in soluble phosphorus concentration and pH value affect the microstructure and amount of hydrates. Combined with experimental results, it has been demonstrated that the delay in the hydration of PESC by PG content is mainly due to: the excessive dissolution of Ca2+ and SO42- promotes the recrystallization of dihydrate gypsum; the dissolution of soluble phosphorus reduces the pH value in the pore solution and forms precipitates of calcium phosphate and hydroxyapatite; in the initial reaction period, a large amount of ettringite and C-S-H gel precipitate to form a protective film; the decrease in pH value leads to a decrease in carbonization resistance, and CO2 in the air is more likely to attack the PESC paste, react with alkaline substances in PESC, or degrade hydrated C-S-H and ettringite. The above factors all lead to a decrease in exchangeable ions during the hydration, thereby prolonging the setting of PESC.

Investigation of fermentation profiles, bacterial community structure and bacterial β-carotene synthesis of alfalfa silage treated with propionic acid or its combination with squalene

Abstract This study examined the fermentation dynamics, bacterial community composition and bacterial β-carotene synthesis in alfalfa that was ensiled for 3, 15, 45 and 90 days without additives (CON), or with a chemical agent (propionic acid, PA); or a combination of PA and squalene, SQPA). The results showed that silage treated with PA had a lower (P < 0.01) pH value than the CON silage in the early ensiling phase (3–15 days). Meanwhile, silage treated with PA had the highest contents of lactic acid, acetic acid and PA after 90 days of ensiling (P < 0.01). The β-carotene in alfalfa was lost seriously in the initial ensiling phase (3 days) and epiphytic Pantoea agglomerans with the ability to produce β-carotene became extinct. With the extension of ensiling time, the loss of β-carotene was alleviated in all silages. PA and SQPA not only lowered bacterial diversity and simplified bacterial networks but also facilitated the emergence of new β-carotene-producing bacteria. The metabolic function prediction indicated that β-carotene synthesis tended to decrease initially and subsequently increase during ensiling. Furthermore, the variance of enzymes involved in the bacterial synthesis of β-carotene in silages was influenced by PA, SQPA and ensiling time. In summary, the impact of solely adding PA demonstrated superior effects on the fermentation quality of alfalfa silage compared to the effects observed with SQPA. Throughout the ensiling of alfalfa, the succession of different β-carotene-producing bacteria resulted in fluctuations in the levels of β-carotene.

Tidally driven porewater exchange and diel cycles control CO2 fluxes in mangroves on local and global scales

Mangrove soils are highly enriched in organic carbon. Tidal pumping drives seawater and oxygen into mangrove soils during flood tide and releases carbon-rich porewater during ebb tides. Here, we resolve semi-diurnal (flood/ebb tides), diel (day/night) and weekly (neap/spring tides) drivers of porewater-derived CO2 fluxes in two mangroves and update global estimates of CO2 emissions building on earlier observations from other sites. Tidal pumping controlled pCO2 variability within the two mangrove creeks. The highest values of pCO2 (2,585–6,856 µatm) and 222Rn (2,315–6,159 dpm m−3) and lowest values of pH (6.8–7.1) and dissolved oxygen (1.7–3.7 mg L−1) at low tides were due to enhanced porewater export. 222Rn and pCO2 in mangrove porewater were 4–15 and 38–41 times greater than surface waters, respectively. pCO2 increased by 50 ± 30 % from high to low tide, 9 ± 22 % from day to night and 57 ± 5 % from neap to spring tide with clear changes in hourly, diel, and weekly time scales. Combining our new estimates with literature data, global porewater-derived (16 sites) and water-atmosphere (52 sites) CO2 fluxes in mangroves would upscale to 45 ± 12 and 41 ± 10 Tg C y−1, respectively. These fluxes represent 25 % of net primary production and are twice as high as the sediment carbon burial rates in global mangroves. Overall, our local observations and global compilation suggest that porewater-derived CO2 exchange is a major but often unaccounted source of CO2 in mangroves. The porewater-derived CO2 can be emitted to the atmosphere or laterally exported to the ocean and should be included in carbon budgets to solve global imbalances.

Whey Cheeses Containing Probiotic and Bioprotective Cultures Produced with Ultrafiltrated Cow's Whey.

Bovine whey cheese (WC) is a product from southern European countries that presents some challenges: its production process involves high energy inputs; the yield is low; and WC has a short shelf life. The application of ultrafiltration (UF) to bovine whey before manufacture of WC and the employment of protective cultures can reduce these disadvantages. The objective of this research was the production of whey cheeses using ultrafiltrated bovine cheese whey with added probiotics or probiotics plus protective cultures. Three types of WC were produced: control CW without any addition (C); CW with the addition of the probiotic Lactobacillus acidophilus (LA5); and CW with the addition of Lactobacillus acidophilus plus a protective culture containing Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus (LA5FQ4). The WCs were stored under refrigerated conditions for 28 days. The products with added cultures presented lower pH values and higher titratable acidities when compared to the control. Sample LA5 presented the lowest pH and the highest titratable acidity, while LA5FQ4 presented intermediate values. Slight differences were observed between products regarding color parameters, chiefly resulting from storage time. The samples with added cultures were firmer when compared to the control, with LA5 cheeses showing the highest values at the end of the storage. Lactic acid bacteria (LAB) counts were on the order of log 8-9 CFU/g for the products with added cultures. Lower levels of yeasts and molds were detected on the sample with the protective culture (LA5FQ4), so that by the end of storage they presented counts one log cycle lower than C and LA5. Hence, the beneficial impact of the protective culture on the shelf life of the product is evident. Regarding sensory evaluation, LA5FQ4 cheeses obtained the highest scores for all parameters evaluated. It can be concluded that the use of UF associated with the addition of protective cultures can be very useful to reduce the energy consumption of the manufacturing process, to prolong the shelf life of WC and to improve its sensory properties.

A Novel Approach of Polyvinyl Alcohol/Acrylic Acid Based Hydrogels for Controlled Delivery of Diclofenac Sodium.

The aim of this study was to prepare polyvinyl alcohol/acrylic acid (PVA/AA) hydrogels for the controlled release of diclofenac sodium and to develop PVA/AA hydrogels as controlled release carriers to overcome not only the side effects of diclofenac sodium but also sustain its release for an extended period. Diclofenac sodium is employed for relieving pain and fever. The half-life of diclofenac sodium is very short (1-2 h). Hence, multiple intakes of diclofenac sodium are required to maintain a constant pharmacological action. Multiple GI adverse effects are produced as a result of diclofenac sodium intake. A free radical polymerization technique was used for crosslinking PVA with AA in the presence of APS. EGDMA was used as a cross-linker. FTIR and XRD confirmed the preparation and loading of the drug by prepared hydrogels. An increase in the thermal stability of PVA was shown by TGA and DSC analysis. Surface morphology was investigated by SEM. Similarly, water penetration and drug loading were demonstrated by porosity and drug loading studies. The pH-sensitive nature of PVA/AA hydrogels was investigated at different pH values by swelling and drug release studies. The development and drug loading of PVA/AA hydrogels were confirmed by FTIR and XRD analysis. TGA and DSC indicated high thermal stability of prepared hydrogels as compared to unreacted PVA. SEM indicated a hard and compact network of developed hydrogels. The swelling and drug release studies indicated maximum swelling and drug release at high pH as compared to low pH values, indicating the pH-sensitive nature of prepared hydrogels. Moreover, we demonstrated that drug release was sustained for a prolonged time in a controlled pattern by prepared hydrogels by comparing the drug release of the developed hydrogels with the commercial product Cataflam. The results indicated that prepared PVA/AA hydrogels can be used as an alternative approach for the controlled delivery of diclofenac sodium.

Isolation and Identification of Chicken-Derived Lactic Acid Bacteria: In Vitro Probiotic Properties and Antagonistic Effects against Salmonella pullorum, Staphylococcus aureus, and Escherichia coli.

The development of probiotics capable of quickly colonizing the intestines of animals is important in promoting the healthy growth of livestock. The aim of this study was to screen lactic acid bacteria (LAB) from the intestinal microbiota of chickens with potential applications, and to evaluate their probiotic properties and antagonistic abilities against Salmonella pullorum, Staphylococcus aureus, and Escherichia coli. The results showed that a total of 79 strains with the characteristics of LAB were isolated from the chicken cecum microbiota, of which 7 strains exhibited strong inhibitory activity against S. pullorum, S. aureus, and E. coli. Performing 16s rDNA sequencing revealed that these seven strains were Lactiplantibacillus pentosus (n = 1), Lactiplantibacillus plantarum (n = 3), Lactiplantibacillus paraplantarum (n = 1), Lactiplantibacillus argentoratensis (n = 1), and Lactiplantibacillus fabifermentans (n = 1). Among them, L. pentosus R26 and L. plantarum R32 exhibited superior antibacterial activity. These two strains demonstrated high lactic acid production ability, with survival rates of 86.29% and 87.99% after 3 h of treatment at pH 1.5, 86.66% and 85.52% after 3 h of treatment with 0.5% bile salts, 90.03% and 88.16% after 2 h of treatment with simulated gastric fluid, and 98.92% and 98.22% after 2 h of treatment with simulated intestinal fluid, respectively. Co-cultivation with L. pentosus R26 for 24 h resulted in 50% of the pathogens being antagonized, while almost complete inhibition was observed following 72 h of co-cultivation. In conclusion, L. pentosus R26 and L. plantarum R32 exhibited high antibacterial activity and acid production capability, while also demonstrating satisfactory tolerance to low pH values and high concentrations of bile salts and digestive fluid. The probiotic characteristics and stress resistance of L. pentosus R26 were slightly superior to those of L. plantarum R32, indicating its potential for development as a probiotic.

Effects of Brassinosteroid Hormone on Chemical Composition of Okra (Abelmoschus esculentus L.) under Salt Stress

Following the scientific management of organic manure (poultry) may contribute to reducing environmental pollution and human health, as the current study was conducted with the aim of recycling poultry manure accumulated in the field of poultry farming at the research station - Faculty of Agriculture - Karma site and the impact of varying fermentation durations on organic manure, specifically animal (poultry manure) fermented by different fermentation methods and its impact on the rest of the factors to produce highly decomposed organic manure free of pathogens. Several traditional fermentation methods (compost and water immersion) were followed. and modern (bioreactor), and for a fermentation period of 90 days with an estimate of most of the qualitative characteristics of the organic manure produced and within periods of 15 - 30 - 45 - 60 - 75 - 90 days. The results of the experiment of incubation of poultry manure showed that all the studied traits have changed with the progress of fermentation time and in the same direction, the results demonstrated that fermentation in the bioreactor unit has given the highest values of total nitrogen, total phosphorus and potassium 32.53, 16.72, 20.86, g.kg-1 for the elements mentioned sequentially, while the lowest values of pH 6.68 and C/N ratio 9.96 compared to other fermentation methods.

Effect of fermentation periods of poultry manure on its characteristics when fermented with different ways

Following the scientific management of organic manure (poultry) may contribute to reducing environmental pollution and human health, as the current study was conducted with the aim of recycling poultry manure accumulated in the field of poultry farming at the research station - Faculty of Agriculture - Karma site and the impact of varying fermentation durations on organic manure, specifically animal (poultry manure) fermented by different fermentation methods and its impact on the rest of the factors to produce highly decomposed organic manure free of pathogens. Several traditional fermentation methods (compost and water immersion) were followed. and modern (bioreactor), and for a fermentation period of 90 days with an estimate of most of the qualitative characteristics of the organic manure produced and within periods of 15 - 30 - 45 - 60 - 75 - 90 days. The results of the experiment of incubation of poultry manure showed that all the studied traits have changed with the progress of fermentation time and in the same direction, the results demonstrated that fermentation in the bioreactor unit has given the highest values of total nitrogen, total phosphorus and potassium 32.53, 16.72, 20.86, g.kg-1 for the elements mentioned sequentially, while the lowest values of pH 6.68 and C/N ratio 9.96 compared to other fermentation methods.

Impact of the environmental parameters on single cell protein production and composition by Cupriavidus necator

Due to the rapid increase in the world's population, many developing countries are facing malnutrition problems, including famine and food insecurity. Particularly, the deficiency of protein sources becomes a serious problem for human and animal nutrition. In this context, Single Cell Proteins, could be exploited as an alternative source of unconventional proteins. The aim of the study was to investigate SCP production and composition by Cupriavidus necator under various environmental conditions, temperature and pH values. A mono-factorial approach was implemented using batch bioreactor cultures under well-controlled conditions. Results were compared in terms of bacterial growth and SCP composition (proteins, nucleic acids, amino acids and elemental formula). Complementary analyses were performed by flow cytometry to study cell morphology, membrane permeability and the presence of Poly(3-hydroxybutyrate) (PHB) production. Our data confirmed the ability of C. necator to produce high amount of proteins (69 %DW at 30 °C and pH7). The results showed that temperature and pH independently impact SCP production and composition. This impact was particularly observed at the highest temperature (40 °C) and also the lowest pH value (pH5) providing lower growth rates, cell elongation, changes in granularity and lower amounts of proteins (down to 44 %DW at pH5) and nucleic acids. These low percentages were related to the production of PHB production (up to 44 %DW at 40 °C) which is the first report of a PHB accumulation in C. necator under nutrient unlimited conditions.

Characterization of malolactic fermentation by Lactiplantibacillus plantarum in red grape must

Malolactic fermentation (MLF) is a desirable biotransformation in red and some high-acidity white wines. This process involves the decarboxylation of l-malic acid into l-lactic acid by lactic acid bacteria (LAB). Among them, Oenococcus oeni and Lactiplantibacillus plantarum are the most common, being the last usually used as starter to perform MLF in wine. Compared with O. oeni, L. plantarum is less tolerant to wine conditions such as pH and ethanol; thus, it is preferable to inoculate it in must. The current literature has not yet addressed the impact of some parameters on the inoculation of this bacterium in grape must. Therefore, the aim of this work was to characterize the effect of the inoculum concentration, pH and ethanol tolerance, as well as the inoculation strategy, on the MLF performance of L. plantarum in grape must. We observed that a population < 108 CFU/mL could compromise MLF performance. Additionally, L. plantarum was able to survive at low pH values, such as 2.50, but in the presence of ethanol or a fermenting yeast, it could tolerate pH values in the range of 3.00–3.25. Finally, coinoculation or sequential inoculation with S. cerevisiae allows for the completion of MLF before the end of alcoholic fermentation.

New Insights into the Production of Assyrtiko Wines from the Volcanic Terroir of Santorini Island Using Lachancea thermotolerans.

Assyrtiko is a rare ancient grape variety of Greece, which is known to produce Protected Designation of Origin (PDO) Santorini white wines. Besides the famous character of the volcanic terroir, Assyrtiko of Santorini is also marked by a low pH value and sharp acidity. The aim of the present study was to apply a new inoculation procedure that modulates the fermentation process by maintaining the unique sensorial characteristics of Assyrtiko wines based on acidity. For this purpose, the Lachancea thermotolerans species, known for the formation of lactic acid, was tested in sequential fermentation with three different Saccharomyces cerevisiae strains. At the end of the fermentation process, implantation control for S. cerevisiae strains (interdelta sequence profile analysis) was performed, oenological parameters were determined according to the OIV protocols, and the volatile compounds produced were measured by gas chromatography-mass spectrometry (GC/MS). Finally, all produced wines were evaluated by quantitative descriptive analysis by two groups of experts; the Greek team of oenologists from Santorini Island specialized in Assyrtiko wines, and the French team of oenologists specialized in wine from Bordeaux. As expected, the inoculated strain was the one that dominated the fermentation process, but nine S. cerevisiae indigenous strains were also identified in the produced wines. Lachancea thermotolerans produced 1 g/L of lactic and also modulated the volatile profile of the wines independently of the S. cerevisiae strain used. The origin of the panelists played an important role in bringing up sensorial traits, such as acidity. Our results led to a new interesting application of L. thermotolerans for white wine production adapted to climate change claims.

Macrophage membrane-camouflaged pH-sensitive nanoparticles for targeted therapy of oral squamous cell carcinoma

BackgroundOral cancer is the most common malignant tumor of the head and neck, and 90% of cases are oral squamous cell carcinoma (OSCC). Chemotherapy is an important component of comprehensive treatment for OSCC. However, the clinical treatment effect of chemotherapy drugs, such as doxorubicin (DOX), is limited due to the lack of tumor targeting and rapid clearance by the immune system. Thus, based on the tumor-targeting and immune evasion abilities of macrophages, macrophage membrane-encapsulated poly(methyl vinyl ether alt maleic anhydride)-phenylboronic acid-doxorubicin nanoparticles (MM@PMVEMA-PBA-DOX NPs), briefly as MM@DOX NPs, were designed to target OSCC. The boronate ester bonds between PBA and DOX responded to the low pH value in the tumor microenvironment, selectively releasing the loaded DOX.ResultsThe results showed that MM@DOX NPs exhibited uniform particle size and typical core-shell structure. As the pH decreased from 7.4 to 5.5, drug release increased from 14 to 21%. The in vitro targeting ability, immune evasion ability, and cytotoxicity of MM@DOX NPs were verified in HN6 and SCC15 cell lines. Compared to free DOX, flow cytometry and fluorescence images demonstrated higher uptake of MM@DOX NPs by tumor cells and lower uptake by macrophages. Cell toxicity and live/dead staining experiments showed that MM@DOX NPs exhibited stronger in vitro antitumor effects than free DOX. The targeting and therapeutic effects were further confirmed in vivo. Based on in vivo biodistribution of the nanoparticles, the accumulation of MM@DOX NPs at the tumor site was increased. The pharmacokinetic results demonstrated a longer half-life of 9.26 h for MM@DOX NPs compared to 1.94 h for free DOX. Moreover, MM@DOX NPs exhibited stronger tumor suppression effects in HN6 tumor-bearing mice and good biocompatibility.ConclusionsTherefore, MM@DOX NPs is a safe and efficient therapeutic platform for OSCC.