280 research outputs found
Impact of milk protein type on the viability and storage stability of microencapsulated Lactobacillus acidophilus using spray drying
Three different milk proteins — skim milk powder (SMP), sodium caseinate (SC) and whey protein concentrate (WPC) — were tested for their ability to stabilize microencapsulated L. acidophilus produced using spray drying. Maltodextrin (MD) was used as the primary wall material in all samples, milk protein as the secondary wall material (7:3 MD/milk protein ratio) and the simple sugars, d-glucose and trehalose were used as tertiary wall materials (8:2:2 MD/protein/sugar ratio) combinations of all wall materials were tested for their ability to enhance the microbial and techno-functional stability of microencapsulated powders. Of the optional secondary wall materials, WPC improved L. acidophilus viability, up to 70 % during drying; SMP enhanced stability by up to 59 % and SC up to 6 %. Lactose and whey protein content enhanced thermoprotection; this is possibly due to their ability to depress the glass transition and melting temperatures and to release antioxidants. The resultant L. acidophilus powders were stored for 90 days at 4 °C, 25 °C and 35 °C and the loss of viability calculated. The highest survival rates were obtained at 4 °C, inactivation rates for storage were dependent on the carrier wall material and the SMP/d-glucose powders had the lowest inactivation rates (0.013 day−1) whilst the highest was observed for the control containing only MD (0.041 day−1) and the SC-based system (0.030 day−1). Further increase in storage temperature (25 °C and 35 °C) was accompanied by increase of the inactivation rates of L. acidophilus that followed Arrhenius kinetics. In general, SMP-based formulations exhibited the highest temperature dependency whilst WPC the lowest. d-Glucose addition improved the storage stability of the probiotic powders although it was accompanied by an increase of the residual moisture, water activity and hygroscopicity, and a reduction of the glass transition temperature in the tested systems
The efficiency of regional higher education systems and competition in Russia
This paper explores the correlation between the degree of competition between higher education institutions (HEIs) and the efficiency of regional higher education systems using evidence from the Russian Federation. The choice of the regional system of higher education as a unit of analysis is explained by the features of the Russian system of higher education, especially by "closeness" in the borders of regions. We propose a special approach for the evaluation of the regional higher education system efficiency from the public administration perspective. Using data envelopment analysis (DEA), we investigate the efficiency of higher education systems in the regions and compare the results with the extent of higher education competition within them. The results indicate that higher efficiency scores and higher competition between HEIs in Russian regions are positively correlated. Moreover, by introducing socio-economic context status as a grouping parameter, we are able to specify the conditions of this relationship. The study explores that correlation between efficiency and competition is stronger in developing and low-performing regions. At the same time, higher education systems in developed regions consist of different HEIs, which create a competitive environment, although their efficiency level varies considerably. Taking into account all limitations of the study, these results contain several important issues for policy-making and higher education research discussions. They challenge the universalistic assumptions for the direction of higher education development.Support from the Basic Research Program of the National Research University Higher School of Economics is gratefully acknowledged
Nonlinear waves in counter-current gas–liquid film flow
We investigate the dynamics of a thin laminar liquid film flowing under gravity
down the lower wall of an inclined channel when turbulent gas flows above the
film. The solution of the full system of equations describing the gas–liquid flow faces
serious technical difficulties. However, a number of assumptions allow isolating the
gas problem and solving it independently by treating the interface as a solid wall.
This permits finding the perturbations to pressure and tangential stresses at the
interface imposed by the turbulent gas in closed form. We then analyse the liquid
film flow under the influence of these perturbations and derive a hierarchy of model
equations describing the dynamics of the interface, i.e. boundary-layer equations, a
long-wave model and a weakly nonlinear model, which turns out to be the Kuramoto–
Sivashinsky equation with an additional term due to the presence of the turbulent
gas. This additional term is dispersive and destabilising (for the counter-current case;
stabilizing in the co-current case). We also combine the long-wave approximation with
a weighted-residual technique to obtain an integral-boundary-layer approximation
that is valid for moderately large values of the Reynolds number. This model is
then used for a systematic investigation of the flooding phenomenon observed in
various experiments: as the gas flow rate is increased, the initially downward-falling
film starts to travel upwards while just before the wave reversal the amplitude of the
waves grows rapidly. We confirm the existence of large-amplitude stationary waves by
computing periodic travelling waves for the integral-boundary-layer approximation
and we corroborate our travelling-wave results by time-dependent computations
Racism as a determinant of health: a systematic review and meta-analysis
Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /
Analysis of survival rates and evaluation of prognostic factors in patients with lung metastases from renal cell carcinoma
In patients with lung metastases from renal cell cancer (RCC), it is necessary to search for new prognostic factors influencing survival rates. Aim: To analyze survival rates and identify prognostic factors in patients with lung metastases from RCC. Material and methods. We retrospectively analyzed the data from 655 patients with lung metastases from RCC, who were treated at Moscow city oncology Hospital No. 62 (Moscow) and city clinical oncology center (Saint Petersburg) from 2006 to 2022. Of these patients, 241 (36.8 %) were classified into the intermediate prognosis group, and 278 (42.2 %) into the unfavorable prognosis group. The study investigated clinical and morphologic prognostic factors influencing survival rates in patients with lung metastases from RCC. Statistical analysis was performed using Statistica 10.0 software packages (StatSoft, USA) by constructing Kaplan-Meier curves and survival tables, building a mathematical model of survival. Results. The 3- and 5-year OS rates in patients with lung metastases from RCC (N=655) were 48 % [95 % ci 45–53 %] and 27 % [95 % ci 23–31 %], respectively, with a median OS of 34.9 months [95 % ci 30.4–37.4]. in univariate analysis, ECOG status (p<0.001), histological subtype (p<0.001), Fuhrman grade of tumor differentiation (p<0.001), type and number of metastases (p<0.001), metastases to the bones and liver (p<0.001), lymph nodes (p=0.001), prognosis according to IMDC(p<0.001), nephrectomy and metastasectomy (p<0.001) had a negative impact on OS in patients with lung metastases from RCC. In multivariate analysis, ECOG status 3.66 (2.10–6.39, p<0.001), histological subtype 1.49 (1.10–2.01, p=0.009), grade of tumor differentiation according to Fuhrman 1.54 (1.13–2.09, p=0.006), number of metastases 3.63 (1.44–9.16, p=0.006), prognosis according to IMDC2.27 (1.63–3.17, p<0.001), and nephrectomy 1.87 (1.29–2.70, p=0.001) and metastasectomy 0.69 (0.53–0.88, p=0.003) were additional factors influencing OS rates in patients with lung metastases from RCC. Conclusion. In our study, ECOG status, histologic subtype of RCC, Fuhrman grade of tumor differentiation, number of metastases, IMDC prognosis, and nephrectomy and metastasectomy were additional independent prognostic factors affecting OS in patients with lung metastases from RCC. Further studies are needed to investigate prognostic factors in patients with RCC lung metastases to improve the effectiveness of personalized treatment and survival rates
Molecular Plasmonic Silver Forests for the Photocatalytic-Driven Sensing Platforms
Structural electronics, as well as flexible and wearable devices are applications that are possible by merging polymers with metal nanoparticles. However, using conventional technologies, it is challenging to fabricate plasmonic structures that remain flexible. We developed three-dimensional (3D) plasmonic nanostructures/polymer sensors via single-step laser processing and further functionalization with 4-nitrobenzenethiol (4-NBT) as a molecular probe. These sensors allow ultrasensitive detection with surface-enhanced Raman spectroscopy (SERS). We tracked the 4-NBT plasmonic enhancement and changes in its vibrational spectrum under the chemical environment perturbations. As a model system, we investigated the sensor’s performance when exposed to prostate cancer cells’ media over 7 days showing the possibility of identifying the cell death reflected in the environment through the effects on the 4-NBT probe. Thus, the fabricated sensor could have an impact on the monitoring of the cancer treatment process. Moreover, the laser-driven nanoparticles/polymer intermixing resulted in a free-form electrically conductive composite that withstands over 1000 bending cycles without losing electrical properties. Our results bridge the gap between plasmonic sensing with SERS and flexible electronics in a scalable, energy-efficient, inexpensive, and environmentally friendly way.</p
БИОХИМИЧЕСКИЕ ИЗМЕНЕНИЯ В ОРГАНИЗМЕ КРУПНОГО РОГАТОГО СКОТА ПРИ ФАСЦИОЛЁЗЕ
Functioning of a number of transamination enzymes and alkaline phosphatase as well as some values of carbohydrate and lipid metabolism on background of protein in cattle blood at fasciolosis are studied. Total blood protein was determined by Loury method, alkaline phosphatase activity – by colorimetric method based on the hydrolysis of n-nitrophenol phosphate. The glutamate transferase activity was estimated by L.J. Olsen method, transaminase activity – by Reitman-Frankel method. Cholesterol levels were measured according to Liebermann–Burchard reaction, the pyruvate content was determined using the diphenylhydrazine method, and lactate – according to reaction withparaoxydiphenyl. The functional status of blood at fasciolosis is marked by the decrease in total protein and pyruvate with the increase of activity of glutamate transferase, alkaline phosphatase, lactate and cholesterol.Изучено функционирование ряда ферментов трансаминирования, щелочной фосфатазы, а также некоторые показатели углеводного и липидного обменов на фоне содержания белка в крови крупного рогатого скота при фасциолезе. В сыворотке крови определяли количество общего белка по Лоури и активность щелочной фосфатазы колориметрическим методом на основе гидролиза n-нитрофенолфосфата. Активность глутаматтрансаминазы определяли по методу Олсона, трансаминаз – по методу Рейтмана и Френкеля, содержание холестерола – по реакции Либермана–Бурхарда, пирувата дифенилгидразиновым и лактата – по реакции с параоксидифенилом. Функциональное состояние крови при фасциолезе характеризуется понижением уровня общего белка и пирувата с одновременным увеличением активности глутаматтрансаминазы, щелочной фосфатазы, лактата и холестерола
Liquid Sensor Based on a Piezoelectric Resonator with a Lateral Electric Field Made of Piezo-Ceramics PZT
Поступила: 30.09.2019. Принята в печать: 10.10.2019.Статья является расширенной версией доклада, представленного на 29-й Международной Крымской конференции «СВЧ-техника и телекоммуникационные технологии» — КрыМиКо’2019 (Севастополь, РФ, 8–14 сентября 2019 г.).Received: 30.09.2019. Accepted: 10.10.2019.Экспериментально и теоретически исследовано влияние проводимости жидкости, контактирующей с пьезоэлектрическим резонатором с поперечным электрическим полем на основе пластины пьезокерамики ЦТС-19. В данном резонаторе поперечная компонента механического смещения, не приводящая к радиационным потерям при контакте с жидкостью, является превалирующей. Частотные зависимости реальной и мнимой частей электрического импеданса резонатора показали наличие трех резонансов на частотах 68,7, 97,8 и 264 кГц со значениями коэффициента электромеханической связи 12,2, 14,7 и 6,5 % соответственно. Добротность каждого резонанса при контакте с жидкостью оказалась существенно выше добротности резонатора c продольной акустической волной на основе ниобата лития. Были получены зависимости максимального значения действительной части электрического импеданса такого резонатора от проводимости жидкости. Проведен теоретический анализ влияния проводимости жидкости на характеристики резонатора.This paper demonstrates the results of the study of the sensor based on the resonator with the lateral electric field made of the ceramic PZT for measuring the conductivity of the contacting liquid. This sensor is made of the PZT ceramic plate of 3.54 mm thickness with shear dimension of 20×18 mm2.Two electrodes with the gap width of 4 mm are deposited on one side of the plate. The sensor features the 4 ml plexiglass container, the bottom of which is a resonator. The measured frequency dependences of the real and imaginary parts of the electrical impedance shows three resonances at frequencies of 68.7, 97.8, and 264 kHz. Aqueous solutions of sodium chloride are prepared with different conductivities in the range 3.2 – 9000 μS/cm. We have measured the frequency dependences of the real and imaginary parts of the sensor electric impedance with the liquid of different conductivity. The maximum value of the real part of the electric impedance monotonically decreases and reaches saturation for each resonance peak with increasing liquid conductivity. Theoretical analysis of influence of liquid conductivity on resonator impedance was also performed using equivalent circuit with two parallel branches. First branch included active and reactive resistors that corresponded to excitation of acoustic wave. The second branch includes the static capacitance of the resonator. We describe the presence of the conductive liquid by means of the leakage resistance connected with the capacitance in parallel. We underline that theoretical and experimental dependences are in a good agreement. Therefore the resonator with the lateral electric field based on the ceramic PZT shows high sensitivity to the changes in the conductivity of the liquid due to the high value of the coefficient of the electromechanical coupling. The sensor with liquid presence compared to the sensor made of lithium niobate with a longitudinal acoustic wave has a higher quality factor. We conclude that in the resonator made of piezoceramics, the shear component of the mechanical displacement is prevailing and does not lead to radiation losses.Работа выполнена при частичной финансовой поддержке грантов РФФИ № 19-07-00300, № 19-07-00304.This research is supported by grant No. 19-07-00300, No. 19-07-00304 from the Russian Foundation for basic research
Highly Sensitive Immunochromatographic Identification of Tetracycline Antibiotics in Milk
A rapid immunochromatographic assay was developed for the control of tetracycline (TC). The assay is based on the competition between immobilized TC-protein conjugate and TC in a tested sample for binding with polyclonal anti-TC antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. Conjugation of colloidal gold and the total immunoglobulin (IgG) fraction of polyclonal antibodies was used to increase the assay sensitivity to ensure low content of specific antibodies in the conjugate. This allowed effective inhibition of free TC and conjugate binding in the strip test zone. Photometric marker registration allows control of the reduction of binding, thereby enhancing detection sensitivity. The proposed assay allows TC to be detected at concentrations up to 20 ng/mL, exceeding the limit of detection of the known analogues, in a wide working range (more than two orders) of 60 pg/mL to 10 ng/mL, ensured through the use of polyclonal antibodies. The assay time is 10 min. The efficiency of the designed assay is shown to identify TC in milk; the degree of recovery of TC ranges from 90 to 112%. The precision of the concentrations measurements was no more than 10%
- …
