Microsphere-based scaffolds encapsulating chondroitin sulfate or decellularized cartilage

Extracellular matrix materials such as decellularized cartilage (DCC) and chondroitin sulfate (CS) may be attractive chondrogenic materials for cartilage regeneration. The goal of the current study was to investigate the effects of encapsulation of DCC and CS in homogeneous microsphere-based scaffolds, and to test the hypothesis that encapsulation of these extracellular matrix materials would induce chondrogenesis of rat bone marrow stromal cells. Four different types of homogeneous scaffolds were fabricated from microspheres of poly(D,L-lactic-co-glycolic acid): Blank (poly(D,L-lactic-co-glycolic acid) only; negative control), transforming growth factor-β3 encapsulated (positive control), DCC encapsulated, and CS encapsulated. These scaffolds were then seeded with rat bone marrow stromal cells and cultured for 6 weeks. The DCC and CS encapsulation altered the morphological features of the microspheres, resulting in higher porosities in these groups. Moreover, the mechanical properties of the scaffolds were impacted due to differences in the degree of sintering, with the CS group exhibiting the highest compressive modulus. Biochemical evidence suggested a mitogenic effect of DCC and CS encapsulation on rat bone marrow stromal cells with the matrix synthesis boosted primarily by the inherently present extracellular matrix components. An important finding was that the cell seeded CS and DCC groups at week 6 had up to an order of magnitude higher glycosaminoglycan contents than their acellular counterparts. Gene expression results indicated a suppressive effect of DCC and CS encapsulation on rat bone marrow stromal cell chondrogenesis with differences in gene expression patterns existing between the DCC and CS groups. Overall, DCC and CS were easily included in microsphere-based scaffolds; however, there is a requirement to further refine their concentrations to achieve the differentiation profiles we seek in vitro

State estimation of chemical engineering systems tending to multiple solutions

A well-evaluated state covariance matrix avoids error propagation due to divergence issues and, thereby, it is crucial for a successful state estimator design. In this paper we investigate the performance of the state covariance matrices used in three unconstrained Extended Kalman Filter (EKF) formulations and one constrained EKF formulation (CEKF). As benchmark case studies we have chosen: a) a batch chemical reactor with reversible reactions whose system model and measurement are such that multiple states satisfy the equilibrium condition and b) a CSTR with exothermic irreversible reactions and cooling jacket energy balance whose nonlinear behavior includes multiple steady-states and limit cycles. The results have shown that CEKF is in general the best choice of EKF formulations (even if they are constrained with an ad hoc clipping strategy which avoids undesired states) for such case studies. Contrary to a clipped EKF formulation, CEKF incorporates constraints into an optimization problem, which minimizes the noise in a least square sense preventing a bad noise distribution. It is also shown that, although the Moving Horizon Estimation (MHE) provides greater robustness to a poor guess of the initial state, converging in less steps to the actual states, it is not justified for our examples due to the high additional computational effort

An outline of an asymmetric two-component theory of aspect

The paper presents the bases of an asymmetric two-component model of aspect. The main theoretical conclusion of the study is that (grammatical) viewpoint aspect and situation aspect are not independent aspectual levels, since the former often modifies the input situation aspect of the phrase/sentence. As it is shown, besides the arguments and adjuncts of the predicate, viewpoint aspect is also an important factor in compositionally marking situation aspect. The aspectual framework put forward in the paper is verified and illustrated on the basis of the aspectual system of Hungarian and some examples taken from English linguistic data

Models of classroom assessment for course-based research experiences

Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education

Small City and Rural Transportation: A Review

The goals and objectives of providing public transportation services in small cities and rural areas are different from those of metropolitan regions. For the small cities and rural areas, the primary purpose is supplying transportation services to meet basic needs of people who do not have any convenient means of transportation. This group can be classified collectively as the carless. Carless simply implies that automobile transportation is not available. This group includes the poor, handicapped, elderly, and youth, as well as, members of households that do not own an automobile or do not have access to an automobile. The mobility needs of the carless are examined in this review. The characteristics of the special mobility groups are studied. The emphasis of the review is on the planning process and operation of public transportation services in the small cities and rural areas. A summary of the characteristics of existing nonmetropolitan transportation services is also presented. The state of the art in nonmetropolitan transportation planning is one of considerable disjointed effort. Although there has been careful planning related to the implementation of public transportation operations in the rural areas and small cities, little systematic development of goals, objectives, policies, and criteria could be found. The high per capita costs of providing transportation services to a small disadvantaged group require careful analyses with respect to the equity and efficiency of costs and benefits. In view of increasing competition of various public and social services for very limited funds, there will be greater demand for careful accounting and justification of public transportation services in small cities and rural areas

Public Transportation and the Carless in Small Cities and Rural Areas: An Annotated Bibliography

This annotated bibliography is prepared for those who are interested in the problem, concerned citizens and planners in small cities and rural areas, and policy analysts in various levels of government. Public transportation planning in nonmetropolitan areas has been disjointed. There are few well developed goals, objectives, and policies. Standards and values are varied among different communities. Consequently, decisions on public transportation services can best be made locally with active citizen participation. This bibliography, together with a review paper (ITS Report D-SR-77-2), provides adequate information for gaining insights into the various facets of the problem. Additional information and assistance can be obtained from the library of the Institute of Transportation Studies (Berkeley and Irvine), the Division of Mass Transportation - California Department of Transportation, the Urban Mass Transportation Administration - U.S. Department of Transportation, and other agencies or institutes. The bibliography is divided into three sections. The first section is a list of references arranged alphabetically by author. Each article is classified by a system of coded keywords. The keyword codes are shown in parentheses after each reference. The second section contains the abstracts of the articles. The third section is an index of articles by subject. The cross-reference is shown by the article number

An Automated and Lightweight Framework for Electrolyte Diagnostics using Quantitative Microelectrode Voltammetry

Voltammetry is a ubiquitous electroanalytical method that can be used to help probe sustainable electrochemical technologies. When conducted with a microelectrode (radius ca. μm), voltammetry enables special interrogation of electrolyte solutions by minimizing distortions and facilitating near-steady-state measurements. Methodologies aimed to evaluate the behavior of redox-active species often leverage well-established, physically-grounded expressions that can be extended to examine electrolyte solutions under non-ideal conditions (e.g., signal convolution from multiple redox events) by simulating the entire voltammogram. To characterize these analyte systems, we first develop closed-form expressions—building on previous work that utilizes oblate spheroidal coordinates—and establish a framework for rapidly evaluating electrolyte composition. We subsequently apply finite difference transient voltammogram models to assess the performance of this workflow. We then validate our findings using model, deterministically-prepared nonaqueous electrolyte solutions containing N-[2-(methoxyethoxy)ethyl]phenothiazine, finding the toolkit is particularly adept at rapidly (< 1 min) estimating the degree to which an electrolyte solution is charged (its “state-of-charge”) and remains intact (its “state-of-health”). Finally, we highlight potential extensions of this method towards advancing in situ or operando diagnostic methods within operating electrochemical devices