Enteric Biopolymer Composite Coatings to Enhance the Viability of Powdered Probiotics During Preparation, Storage, and Simulated Digestions

Due to suppressed metabolisms, powdered probiotics are generally more stable and more convenient for applications than the liquid form, but much work is needed to improve viability of powdered probiotics during processing, storage, and digestions. The goal of this dissertation was to fabricate delivery systems with an enteric biopolymer coating and a core of powdered probiotic ingredients. The principle of preparing powdered probiotics was to directly mix a concentrated cell suspension with hygroscopic food ingredient powders. Amorphous spray-dried lactose (SDL) was first studied to prepared powdered Lactobacillus salivarius NRRL B-30514 in chapter 2. A smaller amount of cell suspension resulted in reduced water activity and lower hypertonic stress and therefore greater viable bacterial counts initially and during subsequent 6-month storage. The suspension: lactose ratio remarkably affected the lactose crystallinity and physiological states of L. salivarius. In chapter 3, milk protein concentrate (MPC) was mixed with SDL at different mass ratios before mixing with the cell suspension. MPC was suggested to preferentially absorb water in cell suspensions, which inhibited the hydration of SDL and thus lowered the hypertonic pressure to the adhered cells. To further improve probiotics viability, amorphous sucrose prepared by co-spray drying with whey protein isolate (WPI) was studied in chapter 4 to utilize the synergistic protection effects of WPI and sucrose. The WPI-Sucrose-probiotics powders (WSPP) with a higher amount of amorphous sucrose showed higher probiotics viability before and after 30-day storage and heating. In order to deliver powdered probiotics, modified rice protein (MRP)-ammonium shellac (NH4SL) enteric composite coatings were studied in Chapter 5 and interactions between MRP and NH4SL were studied. MRP and NH4SL formed complexes to enable suspension of MRP to form smooth films with improved mechanical and enteric properties. A higher content of MRP preserved films better at gastric conditions, and the resultant coating significantly improved the viability of enclosed WSPP pellets after 30-day ambient storage, heating at 80 ºC for 20 min, and during simulated gastrointestinal digestions. The novel, simple and cost-effective approaches studied in the present dissertation to prepare powdered probiotic ingredients are significant to manufacturing solid probiotics-containing products

Technical and Vocational Education in China: The Characteristics of Participants and Their Labor Market Returns

This dissertation study focuses on upper secondary technical and vocational education (TVE) in China. It empirically examines the characteristics of TVE participants and the labor market impacts of participating in upper secondary TVE relative to attending general high schools. Using nationally representative datasets from China, this study has found that compared with individuals who attended general high schools, participants of upper secondary TVE tend to be from relatively disadvantaged family background. The negative association between family background and TVE participation is more pronounced for female TVE students. There is some evidence that girls are more likely to attend vocational education, especially the elite secondary specialized schools. Students of secondary specialized schools are from relatively selective family backgrounds compared with students of the other types of upper secondary TVE. In terms of labor market impacts, the study has found positive effects of attending upper secondary TVE on earnings, employment rate, and the likelihood of working full-time and working under formal contract. The effects are concentrated among females and students of secondary specialized schools. Considering that females are more likely to attend TVE, and that female TVE participants are more likely to come from less selective family background, the larger positive effects of attending TVE relative to general high schools among females may indicate improvement in equality both across genders and within females

Zero-shot Skeleton-based Action Recognition via Mutual Information Estimation and Maximization

Zero-shot skeleton-based action recognition aims to recognize actions of unseen categories after training on data of seen categories. The key is to build the connection between visual and semantic space from seen to unseen classes. Previous studies have primarily focused on encoding sequences into a singular feature vector, with subsequent mapping the features to an identical anchor point within the embedded space. Their performance is hindered by 1) the ignorance of the global visual/semantic distribution alignment, which results in a limitation to capture the true interdependence between the two spaces. 2) the negligence of temporal information since the frame-wise features with rich action clues are directly pooled into a single feature vector. We propose a new zero-shot skeleton-based action recognition method via mutual information (MI) estimation and maximization. Specifically, 1) we maximize the MI between visual and semantic space for distribution alignment; 2) we leverage the temporal information for estimating the MI by encouraging MI to increase as more frames are observed. Extensive experiments on three large-scale skeleton action datasets confirm the effectiveness of our method. Code: https://github.com/YujieOuO/SMIE.Comment: Accepted by ACM MM 202

A Benefit-Cost Analysis of City Connects

Schools have historically and increasingly played an important role in providing services to meet students’ social and emotional, family, health, and academic needs. Coordinating these services in a way that is strategically aligned with a school’s academic mission and that efficiently addresses the needs of all students is often challenging and costly. This study is an initial investigation of Boston College’s City Connects program, which supports students and schools by evaluating the needs of all students in a school and connecting them to services that are largely provided by community partner organizations. The program aims to help students by connecting them with an individualized set of services to address their academic, social/emotional, family, and health needs. The program also aims to assist schools by connecting them with community agencies and service providers, and streamlining student support referral and management to make the process of providing comprehensive approaches to supporting student learning more strategic and efficient. Prior research has shown evidence of effectiveness of City Connects in terms of increased achievement and educational attainment relative to similar schools that have not implemented the program (City Connects Progress Report, 2014; Walsh, et al., 2014a; 2014b). These positive effects must be weighed against the program’s costs in a benefit-cost analysis to determine whether the program is a worthwhile social investment. This report shows that City Connects provides a whole-school comprehensive service at relatively low cost to the schools—schools themselves only bear about 10% of the core costs of the program. However, the methodological complexity of this work is entailed in the estimation of the total cost when considering the partnerships with community organizations. The results show that the total cost of six years of participation in City Connects from kindergarten through fifth grade (the dosage under which effects were measured) is $4,570 per student, which includes a portion of the costs of the community partner services received by the students in City Connects schools. Depending on what share of the community partner services are considered to be above and beyond the baseline level, the total cost estimate can range from$1,540 to $9,320 per student. Under the model that is most plausible based on implementation data, the benefit-cost ratio is 3.0 and the net benefits are$9,280 per student. This result implies that providing the program to a cohort of 100 students over six years would cost society $457,000 but yield$1,385,000 in social benefits, for a net benefit of $928,000. Even under the most conservative assumptions regarding costs and benefits, the program’s benefits exceed its costs. Sensitivity tests show that the benefit-cost ratio lies somewhere between 1 and 11.8, with a best estimate of$3.00 in benefits per dollar of cost. Further research can investigate the relationship between the program, schools, and community partners and how services provided by partners compare in treatment versus comparison schools

A Novel Wireless Localization Fusion Algorithm: BP-LS-RSSI

With the increasing demand for location-aware services, high-precision indoor positioning play more important role for some applications. People also put forward higher requirements on positioning accuracy. BP neural network as a kind of typical forward neural network has the very strong self learning ability and can approximate any discontinuity of rational function. This paper proposes BP-LS-RSSI localization model, then use the model to fix received signal strength indication (RSSI) values for positioning by the LS algorithm. Since the positioning accuracy do not satisfy the needs by the traditional LS algorithm, we transfer the RSSI values into confidence weights according to the topology of network, then use the weighted least squares (LS) method to further optimize the positioning system. Simulation results show that the proposed algorithm has obvious increase to the positioning accuracy is a feasible localization algorithm

Tunable hysteresis effect for perovskite solar cells

Perovskite solar cells (PSCs) usually suffer from a hysteresis effect in current–voltage measurements, which leads to an inaccurate estimation of the device e fficiency. Although ion migration, charge trapping/ detrapping, and accumulation have been proposed as a b asis for the hysteresis, the origin of the hysteresis has not been apparently unraveled. Herein we reporte d a tunable hysteresis effect based uniquely on open- circuit voltage variations in printable mesos copic PSCs with a simplified triple-layer TiO 2 /ZrO 2 /carbon architecture. The electrons are collected by the compact TiO 2 /mesoporous TiO 2 (c-TiO 2 /mp-TiO 2 )bilayer, and the holes are collected by the carbon layer. By adj usting the spray deposition cycles for the c-TiO 2 layer andUV-ozonetreatment,weachievedhysteresis-norm al, hysteresis-free, and hysteresis-inverted PSCs. Such unique trends of tunable hysteresis are anal yzed by considering the polarization of the TiO 2 /perovskite interface, which can accumulate positive charges reversibly. Successfully tuning of the hysteresis effect clarifies the critical importance of the c-TiO 2 /perovskite interface in controlling the hysteretic trends observed, providing important insights towards the understanding of this rapidly developing photovoltaic technology