Lag Time Values Research Articles

Piperonal protects neuron-like and retinalpigment epithelial (RPE) cells from oxidative stress and apoptosis through inhibition of α-synuclein aggregation

Protein fibrillation is a crucial process in the onset of several neurodegenerative and retinal disorders due to the formation of cytotoxic species. Because of their capacity to prevent protein aggregation, small molecules have the potential to be appointed as therapeutic agents. Here, we examined the inhibitory impacts of the piperonal as a carbaldehyde-derived compound on the fibrillation process of α-synuclein and underlying cytotoxicity against neuron-like (PC12) and human retinal pigment epithelial (RPE) (ARPE-19) cells. The results showed that the values of kapp and lag time of α-synuclein were modulated with piperonal. Moreover, ANS fluorescence intensity analysis indicated that piperonal can inhibit the formation of a molten global (misfolded) state of α-synuclein, which is a necessary step in the formation of protein amyloid fibrils. Congo red absorption and circular dichroism spectroscopy also verified the inhibition of β-sheet structure formation after treatment of α-synuclein with piperonal. Furthermore, theoretical studies displayed that piperonal interacts with VAL40:HN, GLU35:O, VAL40, and LYS43 amino acid residues and forms a complex. In addition, cytotoxicity assays demonstrated that piperonal as a safe small molecule could mitigate the induced cytotoxicity by α-synuclein amyloids in PC12 and ARPE-19 cells through reduction of ROS and Bax/Bcl2 mRNA overexpression. Taken together, these outcomes showed that piperonal as a natural aldehyde compound can inhibit α-synuclein fibrillation and underlying cytotoxicity which may be developed for potential therapeutic applications in vivo.

Designing an explainable bio-inspired model for suspended sediment load estimation: eXtreme Gradient Boosting coupled with Marine Predators Algorithm

This study aimed to develop an accurate and reliable model for predicting suspended sediment load (SL) in river systems, which is crucial for water resource management and environmental protection. While Xtreme Gradient Boosting (XGB), a powerful ensemble machine learning (ML) model, has been employed in previous studies, the novelty of this research lies in the introduction of a hybrid approach that synergistically combines XGB with the bio-inspired Marine Predators Algorithm (XGB-MPA) to estimate SL in the Yeşilirmak River (Turkey). To this end, streamflow (Q) and sediment concentration (SC) values as well as their lag times (1 to 3 month lag times) were fed as input variables – under 9 scenarios – into ML models. A time series of datasets from March 1973 to December 2011 and January 2012 to March 2023 were used for training and testing of ML models, respectively. The superiority of the proposed model (XGB-MPA) compared to two other hybrid models, including XGB-PSO (Particle Swarm Optimization) and XGB-GWO (Grey Wolf Optimization) was also investigated. According to the results, the simultaneous application of Q and SC lag time values as inputs has led to the best SL estimates by XGB-MPA, with XGB-MPA9 (RMSE = 103.7 ton/day; NSE = 0.96) exhibiting the lowest error rates. In addition, XGB-MPA has performed better than XGB in all scenarios, with the lowest and highest reduction in RMSE being 19.3% (scenario 5) and 97.4% (scenario 1), respectively. When comparing the performance of hybrid models, the proposed XGB-MPA model has performed best with MAE, RMSE and NSE of 40.94, 103.7 and 0.96, respectively, in comparison with 816.02, 1063.74 and −2.94 for XGB-PSO and 693.16, 981.68 and −2.37 for XGB-GWO. Further research can include the use of time series of efficient variables extracted from satellite images (e.g. land cover, river morphology, etc.) as model inputs. Highlights Improvement of SL estimation by coupling MPA with XGB model Using delayed combinations of streamflow and sediment concentration as model inputs Superiority of MPA compare to PSO and GWO in SL estimation Greater variations in SHAP caused by sediment concentration compared to streamflow Further studies required on the effects of hydrological and topographical features

Evaluation of the impact of anthropogenic storage on the hydrological drought propagation in two contrasting semi-arid river basins

ABSTRACT This study quantitatively investigated reservoir-effects on drought propagation in two semi-arid river basins: India’s Tapi basin with the Ukai reservoir and Uzbekistan’s Chirchik basin with the Charvak reservoir. Meteorological drought (MD) is analyzed using the Standardized Precipitation Index (SPI) and hydrological drought (HD) using the Standardized Streamflow Index (SSI) for the duration from 1980 to 2004. Both the river basins, especially in upstream reservoir areas, exhibited a notable correlation between HD and MD. Reservoir operation was observed to reduce the downstream MD–HD correlation at shorter SPI timescales. Hit-score-based evaluations indicated that reservoir operation has induced changes in the drought propagation patterns for both river basins. Due to the contrasting characteristics, the river basins showed a significant variation in the drought propagation time (DPT), with distinct influences from monsoon (Tapi) and snow-melting (Chirchik). The average DPT (average DPT over 12 months) for the reservoir-influenced part of the Tapi (∼ six months) and Chirchik (∼ nine months) basins is higher than that of the natural parts of both basins (Tapi: ∼ four months; Chirchik: ∼ six months) as a result of the natural and anthropogenic storage influence.

Induction into viable but non culturable state and outgrowth heterogeneity of Listeria monocytogenes is affected by stress history and type of growth

Exposure to sublethal stresses related to food-processing may induce a heterogenous mixture of cells that co-exist, comprising healthy, sublethally injured, dormant and dead cells. Heterogeneity in survival capacity and dormancy of single cells may impede the detection of foodborne pathogens. In this study, we exposed Listeria monocytogenes Scott A strain, to peracetic acid (PAA; 20–40 ppm) and to acidic conditions (hydrochloric (HCl) and acetic (AA) acid, adjusted to pH 2.7–3.0, to evaluate the resuscitation capacity and outgrowth kinetics of metabolically active cells in two different media. Injury and the viable-but-non-culturable (VBNC) status of cells were assessed by flow cytometry using CFDA (metabolically active) and PI (dead) staining. Stressed CFDA+PI− cells were sorted on Tryptic Soy (TS) Agar or in TS broth, both supplemented with 0.6 % Yeast Extract (TSAYE or TSBYE), to evaluate culturability. Resuscitation capacity of CFDA+PI−sorted cells (10 events/well) was monitored by visual inspection on TSAYE and by optical density measurement in TSBYE for 5 days. Sorting of L. monocytogenes viable cells (CFDA+PI−) in Ringer's solution on TSAYE and TSBYE showed 100 % recovery in both media (control condition), while the mean lag time in TSBYE was 9.6 h. Treatment with 20 ppm PAA for 90 and 180 min resulted in 74.79 % and 85.82 % of non-culturable cells in TSBYE and increased the average lag time to 41.7 h and 43.8 h, respectively, compared to the control (9.6 h). The longest average lag time (79.5 h) was detected after treatment with 30 ppm PAA for 90 min, while at the same condition sorting of CFDA+PI− cells resulted in 95.05 % and 93.94 % non-culturable cells on TSAYE and TSBYE, respectively. The highest percentage of wells with non-culturable cells (96.17 %) was detected on TSAYE after treatment with 40 ppm PAA for 30 min. Fractions of VBNC cells were detected in TSBYE after treatment with HCl pH 3.0 for 60 and 240 min, and in TSAYE and TSBYE after exposure to AA pH 2.7. Treatment with AA pH 2.7 for 150–300 min increased the range of recorded lag time values compared to 60 min, from 8.6 h up to 13.3 h, as well as the mean lag times in TSBYE. Modelling of the outgrowth kinetics comparing the two types of stress (oxidative vs acid) and the two systems of growth (colonial vs planktonic) revealed that low starting concentrations hindered the detection of viable L. monocytogenes cells, either due to VBNC induction or cell heterogeneity.

Efficiency of C-type natriuretic peptide on improvement of Iraqi local ram's epididymal sperms.

Fertility plays a great role in animal reproduction since high-quality semen improves sheep industry reproduction. The current worldwide data revealed the close relation of C-type natriuretic peptide (CNP) to the reproductive function of rams. Evaluation of the effect of CNP on cooled sperms using traditional and molecular assays. Totally, of 20 testicular samples were collected, processed to obtain the semen samples, and divided into two parts; one was treated with a suitable dose of CNP, and the other served as a control. Sperm samples of both groups were cooled for 3 days and tested at 0, 24, 48, and 72 hours. The findings revealed that the suitable dose of CNP-treated sperms was 0.01 × 10-13. Values of individual motility, live sperms, and sperm concentration were reduced significantly in CNP-24h, CNP-48h, and CNP-72h when compared to control; however, abnormal sperms were increased in both control and CNP groups at 24, 48, and 72 hours when compared to values of 0 hour. Concerning turbidmetric analysis, a significant reduction in values of lag time was observed in CNP when compared to control at all times of cooling intervals. In both CNP and control groups, motility index was decreased at 24, 48, and 72 hours when compared to 0 hour. For velocity, significant increases were shown in CNP compared with control at all cooling intervals. However, values of both groups were increased significantly at 24, 48, and 72 hours times when compared to 0 hour. Fraction of rapidly moving sperm of CNP was elevated at 0 hour and decreased at 24, 48, and 72 hours when compared to control. Expression of the hNPR-B gene was reduced gradually in sperms of CNP and control groups at times of cooling intervals. To the best of our knowledge, this first Iraqi study targets the effect of CNP on epididymal sperms of rams. However, changes that occur after excessive CNP exposure remain unclear, and the toxicological profile of CNP requires furthermore supplements.

Lag time of modern bomb-pulse radiocarbon in human bone tissues: New data from Brazil

Radiocarbon analysis with reference to the modern bomb-curve was conducted using 68 bone samples of a vertebral body, femoral diaphysis, occipital bone, and parietal bone of 17 adults from Brazil. All individuals were born in 1963, thus analysis focused on the correlation with atmospheric values during the more recent, falling portion of the curve. Ages at death ranged from 43 to 54 years with representation of both sexes. Lag time (difference between the actual death date and the year of correspondence of the radiocarbon value with the curve) was evaluated for each individual and each tissue. The mean of the lag time values was 20.2 years, and the median was 22.0 years. The femur had the highest lag time median (29.5 years) among the bone groups, followed by the occipital (25.5 years), parietal (23.5 years) and the vertebra (8.0 years). The same pattern was observed for both sexes, but females tended to have lower lag time values than males. Different tissues presented considerable variation in lag time with vertebral bodies the least and the femoral diaphysis the greatest. These data suggest that individual age at death and the associated lag time must be considered in estimating the approximate death date. The lag time values for vertebral bodies were lower and with less variability in comparison with values for the occipital, parietal, and femur indicating greater consistency of that bone group for time since death estimation in the studied sample.

Fabricate and Characterization by Ionotropic Gelation Technology of the MicroBeads Loaded with Dicyclomine Hydrochloride for Gastroretentive Drug Delivery System

Objectives: The principal objective of this research is to fabricate, characterize and in vitro evaluation of floating gastroretentive Dicyclomine Hydrochloride beads. Methods: In this study, Ionotropic gelation technology was used to float gastro retentive Dicyclomine Hydrochloride beads. Subsequently, the floating properties, entrapment efficiency, in vitro release of beads were all determined during the characterization process. Results: The results showed concluded that formulation B11 have shown higher total floating time and lesser floating lag time values and a better drug release profile. Conclusion: Six formulations B3, B6, B9, B10, B11, and B12, met all of the requirements and features necessary for a successful floating formulation. For the preparations, all of the evaluation tests were completed. With changes in the ratio of sodium alginate and Hydroxypropyl Methylcellulose and the number of effervescent agents in the formulations, the formulations’ drug release pattern and floating capabilities were shown to be varied. The experiment and the results reveal that Dicyclomine Hydrochloride floating beads enhance stomach residence and bioavailability while decreasing the dosage and dosage interval.

Contact activated kallikrein generation is reduced six months after gastric bypass

BackgroundProthrombotic and inflammatory variables decrease after obesity surgery. The contact activation system may be a common denominator of these changes. ObjectiveTo characterize the contact system before and 6 months after Roux-en-Y gastric bypass (RYGB) and to evaluate associations with changes (post-surgery minus pre-surgery) in metabolic variables. MethodsWomen (n = 42) and men (n = 18) with obesity underwent RYGB, and measures of kallikrein generation, factor XII (FXII), prekallikrein, high molecular weight kininogen (HK), and C1 esterase inhibitor (C1-inh) were determined before and 6 months after surgery. Associations were evaluated using correlation and multivariate regression analyses. ResultsAfter RYGB, the endogenous kallikrein potential (EKP), peak kallikrein generation, FXII, and prekallikrein were reduced, and kallikrein generation lag time was prolonged (all p < 0.0005). Before and after RYGB, absolute values of EKP, lag time, and peak kallikrein generation correlated consistently with contact system proteins (range of correlation coefficients (rS): −0.43 to −0.28 and 0.24 to 0.45 (pre-surgery); −0.43 to −0.30 and 0.28 to 0.50 (post-surgery)). RYGB-associated changes in EKP correlated with C1-inh (rS = −0.29, p = 0.025), but also with triglycerides (rS = 0.34, p = 0.007) and cholesterol (rS = 0.28, p = 0.029), and independently associated with changes in C1-inh (β = −0.40) and triglycerides (β = 0.39). Changes in C1-inh associated with reductions in body weight (β = −0.39) and HbA1c (β = 0.38). ConclusionThe contact system was affected 6 months after RYGB. Absolute values of kallikrein generation before and after RYGB correlated with contact system proteins, whereas changes after RYGB associated with changes in C1-inh and metabolic variables.

Investigating the growth kinetics in sourdough microbial associations

In this study we investigated the effect of the single strain in stabilization of type I sourdough microbial associations by crossing six different Fructilactobacillus sanfranciscensis with five Kazachstania humilis strains. Furthermore, we compared three predictive models, Zwitwering based on Gompertz's equation, Baranyi and Roberts' function and Schiraldi's function to evaluate which one best fitted the experimental data in determining the behaviour of co-cultivated microorganisms. Specific growth rates (μm) and lag time (λ) values for each mixed population were assessed. Results showed that the different F. sanfranciscensis strains significantly steer the growth kinetics within the pair and affect the ratio bacterial/yeast cells, as data analysis confirmed, whereas K. humilis accommodates to the bacterial strain. To compare the growth models, Root Mean Square (RMS) values were calculated for each predicted curve by implementing an algorithm based on an iterative process to minimize the deviation among observed and calculated data. Schiraldi's function performed better than the others, revealing, on average, the smallest RMS values and providing the best fitting for over 70% of co-cultivation experiments. Models prove to be consistent in predicting growth kinetics of microbial consortia too.

Growth and thermal inactivation of Listeria monocytogenes and Escherichia coli O157:H7 in four kinds of traditionally non‐fermented soya bean products

SummaryThis study evaluated growth and thermal inactivation of Listeria monocytogenes and Escherichia coli O157:H7 inoculated in tofu, dougan, qianzhang and doupi which were stored at 4, 25 and 37 °C and heated at 55, 60, 65 and 70 °C. Growth of the two pathogens in four soya bean products increased with temperature or Aw of soya bean products increasing. At the same temperature, lag time (LT) values of L. monocytogenes (16.32–0.94 h) and E. coli O157:H7 (2.66–0.98 h) in tofu which has the highest Aw were the lowest. When inoculated soya bean products were stored at 4 °C, L. monocytogenes grew slowly, while E. coli O157:H7 did not grow but survived for 14 days. With temperature increasing, δ‐values of L. monocytogenes and E. coli O157:H7 in the four soya bean products were decreased. With Aw of soya bean products increasing, thermal resistance of L. monocytogenes decreased, while that of E. coli O157:H7 increased. This study could assist retail soya bean products processors and food industry to enhance safety of soya bean products and design thermal processing regimes.

Prediction of monthly Hilsa (Tenualosa ilisha) catch in the Northern Bay of Bengal using Bayesian structural time series model

Monthly catch of Hilsa in the Northern Bay of Bengal was modeled and predicted using the Bayesian structural time series (BSTS) with chlorophyll and rainfall as explanatory covariates. Chlorophyll and rainfall were used in the model with a lag time of eleven months and one month, respectively. These lag time values were determined from the exploratory data analysis. In this study, four separate models were developed to predict the Hilsa catch and compare the results. In the first model, the catch was predicted based on trend and seasonality of the previous years’ catch data. The second and third models predicted monthly catch with chlorophyll (having a lag time of 11 months) and rainfall (having a lag time of 1 month), respectively, as the only covariate in the model. The fourth model had both chlorophyll and rainfall as covariates with a lag time of 11 months and 1 month, respectively. The training mean absolute percentage error (MAPE) of the fourth model (measuring model fit) was observed as 0.2827, while the test MAPE (measuring model accuracy) was 0.2786. The coefficient values for both chlorophyll and rainfall were very close (0.999 and 1.064) which indicated the almost equal effect of both the parameters on the Hilsa catch. This study indicated that more abundance of the food material (phytoplankton) during the post-monsoon season would promote the growth and maturity of more Hilsa that would successively migrate towards river or estuary during the subsequent monsoon season and the catch would likely increase with the intensification of the southwest monsoon.

Study on Optimization of Wet Milling Process for the Development of Albendazole Containing Nanosuspension with Improved Dissolution

The main objective of this work was to show the potential of the optimization of top-down wet planetary bead milling process parameters (milling speed, process time and size of the milling medium) by Design Of Experiments (DOE) approach for the development of albendazole (ABZ) containing nanosuspension with improved dissolution. In addition, the influence of process parameters (capacity of milling container, applied volume of milling beads, size of the milling medium, milling speed, milling time) on ABZ polymorphic transition has also been investigated. The optimized, milled formula yielded ~ 145.39 times reduction in mean particle size (182.200 ± 1.3130 nm) compared to unmilled dispersion, which demonstrated 13.50 times gain in mean dissolution rate value compared to the unmilled dispersion in medium at pH = 1.2. No lag time values were observed in the dissolution kinetics of the nanosuspension in comparison with the unmilled samples. Moreover, maximal mean solubility value was also improved by 1.45 times compared to the unmilled suspension, in medium at pH = 6.8, supporting the significance of the Ostwald-Freundlich equation. Diffraction pattern comparisons have indicated a polymorphic transition of albendazole to Form II, which was more pronounced in smaller container at high milling speed values and prolonged operations.

Thermochronological and Geochronological Constraints on Late Cretaceous Unroofing and Proximal Sedimentation in the Sevier Orogenic Belt, Utah

AbstractA source‐to‐sink analysis incorporating geochronometric and thermochronometric data from the Sevier fold‐thrust belt (SFTB) and proximal synorogenic strata of the Canyon Range Conglomerate (CRC) and Indianola Group (IG) provides new insights into orogenic exhumation, erosional unroofing, and the interplay between thrusting and coarse clastic deposition in the Cretaceous Cordilleran foreland basin of western North America. Zircon (U‐Th)/He ages from the Pavant and Nebo thrust sheets record significant Cenomanian cooling indicative of synchronous exhumation and thrusting along a large segment of the SFTB in central and northern Utah. Detrital zircon (U‐Th)/He (DZHe) ages indistinguishable from depositional ages from the Cenomanian Dakota Formation and lower CRC also record rapid unroofing of the SFTB and synchronous deposition. DZHe data from wedge‐top deposits of the CRC record two significant unroofing episodes: Albo‐Cenomanian exhumation of the Pavant thrust and progressive unroofing of the Canyon Range culmination. For the IG, the presence of Paleozoic DZHe ages along with Paleozoic‐Mesozoic DZ U‐Pb ages in the Cenomanian Sanpete Formation suggests derivation from Paleozoic to Jurassic strata exhumed in the frontal Pavant and Nebo thrust sheets. After the Cenomanian episode of rapid exhumation, proximal foredeep strata recorded a widespread DZ provenance shift in the Turonian. Short DZHe lag time values from Campanian CRC and IG deposits reveal rapid exhumation of the SFTB during the Campanian. The synchroneity of major shortening and Campanian and Cenomanian changes in foreland basin architecture and provenance supports models proposing that active shortening in the fold‐thrust belt coincides with coarse clastic influx in foreland basins.

Analysis of a generalized Fujikawa's growth model.

We analyze a generalized form of the Fujikawas growth model which involves an adaptation function that enhances the representation of the lag phase. This model is autonomous, and combines a power law term, a saturation term and an adaptation function that suppresses the growth rate during initial period corresponding to the lag phase. The properties of the adaptation function are determined, and the proposed model is examined separately for the regular measure and the logarithmic measure, including: Convergence and boundedness properties; population at the inflection point; conditions for the existence of the inflection point and lag phase; effect of model parameters on the existence of the inflection point and lag phase; population size of the inflection point under limiting values of the model parameters; and parameter values that lead to inflection point located at the mean value of the curve. Different combinations of model parameters lead to different possibilities for the existence of the inflection point and the lag phase. It was noticed that the power law term has a strong effect on the representation of the exponential growth phase, whereas the adaptation function has a strong effect on the representation of the lag phase. The lag phase duration depends on the exponent parameter of the adaptation function, and its dependence with respect to the power law parameter is low. Also, an approach is proposed for the analytical determination of the lag time, based on the application of the classical approach to a simplified model. Ascertained lag time values were obtained, what confirms the assumptions. At last, the model is applied to experimental data.

Thrombin generation in different commercial sodium citrate blood tubes.

This study aimed to verify whether blood drawn into six different commercial coagulation tubes generated comparable results of thrombin generation. Blood was sequentially collected from 20 healthy subjects into different brand and draw volume 3.2% sodium citrate tubes (4.3 mL Sarstedt, 3.0 mL Greiner, 2.7 mL Becton Dickinson, 2.0 mL Kima, 1.8 mL Sarstedt and 1.0 mL Greiner). Thrombin generation was measured in plasma with the fully-automated ST Genesia analyzer using the weakest trigger (STG-BleedScreen). Different values of lag time (LT), time to reach thrombin peak (TP), thrombin peak height (PH) and endogenous thrombin potential (ETP) were commonly found in different tubes. Thrombin generation was the lowest in 4.3 mL Sarstedt tubes and the highest in 1.0 mL Greiner tubes. Other tubes displayed intermediate values. In multiple comparisons, LT was significantly different in 6/15 cases (40%), whilst PH, TP and ETP were significantly different in 14/15 (93%), 13/15 (87%) and 13/15 (87%) cases. The mean percent bias of LT, PH, TP and ETP ranged between -6% and +1%, -27% and +116%, -22% and +8%, and between -18% and +65%. The intra-assay imprecision of LT, PH, TP and ETP was exceeded in 0/15 (0%), 13/15 (87%), 6/15 (40%) and 13/15 (87%) comparisons. The correlation of LT, PH, TP and ETP values in different tubes ranged between 0.718-0.971, 0.570-0.966, 0.725-0.977 and 0.101-0.904. Blood collection for thrombin generation assays requires local standardization using identical tubes for brand and draw volume, and reference ranges calculated according to type of tubes.

Formulation and Evaluation of Floating Matrix Tablets of Ciprofloxacin Using Sida acuta Gum

Background: Natural polymers have been found to be affordable, easily available, biocompatible and biodegradable. This study was conducted to formulate and evaluate floating matrix tablets of ciprofloxacin using Sida acuta gum (SAG) as hydrophilic polymer. Methods: Sida acuta gum was isolated from the dried powdered leaves of Sida acuta plant by isopropyl alcohol precipitation of the filtrate obtained from its maceration in distilled water. The gum obtained was used to formulate ciprofloxacin floating tablets using direct compression technique. The tablets were evaluated for hardness, friability, uniformity of content, floating lag time, total buoyancy time, in vitro drug release, kinetics and mechanism of release. Results: The formulated tablets gave hardness range of 3.80 ± 0.56 to 5.01 ± 0.61; uniformity of content value range from 99 to 106%, friability values obtained range from 0.44 to 2.41%, and formulated tablets had buoyancy time greater than 12 hours, floating lag time values ranged from <1 min to 90 min. Tablets formulated with 20% hydroxypropylmethylcellulose, HPMC (CF4) gave the highest swelling value of almost 5000%. The drug release profile for the floating tablet formulations after 7 h was 110%, 72%, 106%, 46% and 87% for CF1 (20% SAG), CF2 (30% SAG), CF3 (15/15% SAG and HPMC), CF4 (20% HPMC), CF5 (20% Sodium carboxymethylcellulose) respectively. Conclusion: This study showed that ciprofloxacin floating matrix tablets that have sustained release property could be formulated using Sida acuta gum as the hydrophilic polymer.

Growth and Hemolysin Production Behavior of Vibrio parahaemolyticus in Different Food Matrices

The growth and hemolytic activity profiles of two Vibrio parahaemolyticus strains (ATCC 17802 and ATCC 33847) in shrimp, oyster, freshwater fish, pork, chicken, and egg fried rice were investigated, and a prediction system for accurate microbial risk assessment was developed. The two V. parahaemolyticus strains displayed a similar growth and hemolysin production pattern in the foods at 37°C. Growth kinetic parameters showed that V. parahaemolyticus displayed higher maximum specific growth rate and shorter lag time values in shrimp > freshwater fish > egg fried rice> oyster > chicken > pork. Notably, there was a similar number of V. parahaemolyticus in all of these samples at the stationary phase. The hemolytic activity of V. parahaemolyticus in foods increased linearly with time ( R2 > 0.97). The rate constant ( K) of hemolytic activity was higher in shrimp, oyster, freshwater fish, and egg fried rice than in pork and chicken. Significantly higher hemolytic activity of V. parahaemolyticus was evident in egg fried rice > shrimp > freshwater fish > chicken > oyster > pork. The above-mentioned results indicate that V. parahaemolyticus could grow well regardless of the food type and that contrary to current belief, it displayed a higher hemolytic activity in some nonseafood products (freshwater fish, egg fried rice, and chicken) than in one seafood (oyster). The prediction system consisting of the growth model and hemolysin production algorithm reported here will fill a gap in predictive microbiology and improve significantly the accuracy of microbial risk assessment of V. parahaemolyticus.

Advancing Flavor Stability Improvements in Different Beer Types Using Novel Electron Paramagnetic Resonance Area and Forced Beer Aging Methods

Three different electron paramagnetic resonance (EPR) metrics—lag time, T150, and area—were compared with sensory data from two forced beer aging methods. Three types of beers were evaluated, namely, 1) standard lager, 5% alcohol by volume (ABV) and 3.30° standard reference method (SRM) color; 2) low-alcohol lager, 3% ABV and 2.20° SRM color; and 3) standard ale, 5% ABV and 4.00° SRM color. The two accelerated aging time–temperature treatments evaluated in this study were 18 days at 27°C and six days at 40°C, both being equivalent sensory-wise to our standard flavor stability staling rate of six months at 20°C. A significant relationship between EPR area and sensory staleness scores was found using the 40°C for six days temperature abuse treatment protocol (R2 = 0.9209–0.9567), not the 27°C for 18 days abuse treatment protocol (R2 = 0.0319–0.2046). In addition, the area under the curve metric displayed significant correlation coefficients (R2 = 0.9209–0.9567) with the 40°C for six days abuse treatment staling scores, whereas the traditional lag time and T150 values were not significant (R2 = 0.0174–0.2238 and 0.1010–0.8565, respectively). Using this analytical and sensory chemoetricstyle approach, subsequent brewing materials and process changes were made in the brewing process to lower the EPR area values in five breweries spanning three years of profiling. This resulted in improved packaged beer flavor stability. Using the connection between these novel, rapid methods, this study also highlights three causative beer conditions that have traditionally shown major impacts on flavor stability: namely, trace metals (Cu and Fe), dissolved oxygen, and bisulfite (SO2) levels. Using the EPR area metric, which represents the total amount of free radicals generated during the beer sample analysis time, led the way to engage a rapid forced beer sensory method. Once employed, longer packaged beer shelf-life improvements over the three-year period were realized. This new dynamic program is currently being used in our breweries.

Prediction of growth of Pseudomonas fluorescens in milk during storage under fluctuating temperature

Accurate prediction of growth of undesirable organisms (e.g., Pseudomonas fluorescens) in perishable foods (e.g., milk), held under sub-ideal storage conditions, can help ensure the quality and safety of these foods at the point of consumption. In this investigation, we inoculated sterile milk with P. fluorescens (~103cfu/mL) and monitored inoculum growth behavior at constant and fluctuating storage temperatures. Three storage temperatures, 4°C, 15°C and 29°C, were selected to simulate proper refrigeration conditions (4°C) and temperature abuse, respectively. To simulate temperature fluctuation, milk held at 4°C was subjected to temperature shifts to 15°C or 29°C for 4 to 6h. A modified logistic model was used to obtain the best-fit curve for the microbial growth under constant storage temperature. The specific growth rates at 4°C, 15°C, and 29°C, obtained from experimental data, were 0.056±0.00, 0.17±0.05, and 0.46±0.02h−1, respectively, and the lag time values were 29.5±4.2, 12.7±4.4, and 2.8±0.3h, respectively. A model predicting bacterial growth under different temperature fluctuations was obtained using the growth parameters extracted from constant temperature experiments. Growth behavior predicted by the fluctuating temperature model and that obtained experimentally were in good agreement. Lag time exhibited a larger variation compared with specific growth rate, suggesting that it depends not only on growth temperature but also on the sample population and temperature gradient. Additionally, experimental data showed that changing the temperature during the lag phase induced an additional lag time before growth; however, no significant lag time was observed under the temperature fluctuation during the exponential phase. The results of this study provide information for precise shelf-life determination and reduction of food waste, particularly for milk and milk-containing food products.

Application of Microneedle Arrays for Enhancement of Transdermal Permeation of Insulin: In Vitro Experiments, Scaling Analyses and Numerical Simulations.

The aim of this investigation is to study the effect of donor concentration and microneedle (MN) length on permeation of insulin and further evaluating the data using scaling analyses and numerical simulations. Histological evaluation of skin sections was carried to evaluate the skin disruption and depth of penetration by MNs. Scaling analyses were done using dimensionless parameters like concentration of drug (C t/C s), thickness (h/L) and surface area of the skin (S a/L (2)). Simulation studies were carried out using MATLAB and COMSOL software to simulate the insulin permeation using histological sections of MN-treated skin and experimental parameters like passive diffusion coefficient. A 1.6-fold increase in transdermal flux and 1.9-fold decrease in lag time values were observed with 1.5mm MN when compared with passive studies. Good correlation (R (2) > 0.99) was observed between different parameters using scaling analyses. Also, the in vitro and simulated permeations profiles were found to be similar (f 2 ≥ 50). Insulin permeation significantly increased with increase in donor concentration and MN length (p < 0.05). The developed scaling correlations and numerical simulations were found to be accurate and would help researchers to predict the permeation of insulin with new dimensions of MN in optimizing insulin delivery. Overall, it can be inferred that the application of MNs can significantly enhance insulin permeation and may be an efficient alternative for injectable insulin therapy in humans.