Gels are colloidal states of matter in which a solid matrix is dispersed in a liquid phase. Supramolecular gels are formed due to the self-assembly of small gelator molecules in a suitable solvent as a result of specific weak non-covalent interactions between the gelators. The last several decades have witnessed an upsurge in research activities in the area of supramolecular gels not only for academic interests but also for applications in material science. Gels have been investigated as potential avenues for drug delivery and oil recovery applications. Despite their huge potential, the properties of gels are discovered through trial-and-error approaches, which makes control of properties a challenging task. The control becomes extremely hard in a multicomponent gel system, which is a common model for applications in material science. The aim of this thesis is to design a pathway to gain a fundamental understanding on how multiple components in the gel contribute to new properties. This pathway is an attempt to move away from trial-and-error approaches for the development of gels and allows us to make correlations between structure, dynamics and function. The studies reported in this thesis were performed on a two-component gel system comprising a gelator and an additive. The gelator, sodium deoxycholate (NaDC), is a bile salt known for its ability to form a supramolecular gel within a certain pH range. NaDC gels are made up of aggregates distributed between the aqueous phase and the gel structure. NaDC gels are reversible and considered as promising candidates from a functional point of view. The additive, cucurbit[6]uril (CB[6]), is a macrocycle and is known to affect the mechanical properties of NaDC gels at the macroscopic level. In the first project, I studied the effect of CB[6] on the NaDC gel at the microscopic level using dynamic light scattering and fluorescence microscopy experiments. These techniques were used to determine the effect of CB[6] on the gel’s morphology, size of NaDC aggregates, thermo-reversible properties of NaDC gels and the kinetics of NaDC gel formation. My results showed that the effect of CB[6] on NaDC aggregates begins in solutions and is translated to sols and gels. Thermo-reversibility and kinetic studies showed that the effect of CB[6] on NaDC gels goes beyond changes to the gel’s structure and CB[6] was also shown to affect both the gel-sol transition temperatures and time of the gel formation. In the second project, I studied how the release of dyes of different hydrophobicities from NaDC gels was affected by the addition of CB[6]. The release of the dyes pyrene and rhodamine 6G was investigated using a static diffusion method, which was referred to as the top layer method. My results showed that CB[6] has a different effect on the release kinetics of a hydrophilic dye compared to the release of a hydrophobic dye. The observed difference in the release kinetics was attributed to differences in the localization of the dyes in NaDC gels and the role of CB[6] in affecting the distribution of dyes in different regions in the gel. In the third project, I studied the colocalization of a hydrophobic and a hydrophilic dye in NaDC-CB[6] gels with the goal to confirm my hypothesis from the release studies. Dynamics of diffusion of dyes within NaDC-CB[6] gels was investigated using the fluorescence recovery after photobleaching (FRAP) technique. Results from colocalization experiments showed that the addition of CB[6] changes the distribution of hydrophilic dye in the gel. Through colocalization experiments, I was able to showcase the active role of CB[6] in incorporating aggregates from the aqueous phase into the gel structure. Results from FRAP studies showed that, in the presence of CB[6], recovery after bleaching of a hydrophobic dye in the gel structure is slower compared to the dye in the NaDC gel structure. / Graduate

Ankle foot orthosis (AFO) stiffness affects ankle range of motion but can also provide energy storage and return to improve mobility. To perform multiple activities during the day, a person may want to change their AFO stiffness to meet their activity’s demand. Carrying multiple AFO and changing the AFO is inconvenient and could discourage users from engaging in multiple activities. This thesis developed a new quick-release mechanism (QRM) that allows users to easily change posterior strut elements to change AFO stiffness. The QRM attaches to the AFO and requires no tools to operate. The new QRM includes a quick-release key, weight-bearing pin, receptacle anchor, and immobilization pin. A prototype was modelled with SolidWorks and simulated with SolidWorks Simulation. The QRM was designed to have no mechanical failure during intense activities such as downhill walking and running. Unlike a solid screw connection, the QRM needed an additional part to eliminate unsecured motion related to clearance between the quick release key and receptacle anchor. Mechanical test results and measurement data demonstrated no deformation on each part after mechanical testing. User testing revealed that, although the quick release mechanism can be locked or unlocked rapidly, the person’s posture when operating can facilitate strut swapping. A learning effect occurred by repeated practice. The Quick Release AFO (QRAFO) prototype verified the manufacturing feasibility of the QRAFO design. Overall, the novel quick release AFO improved strut swapping time without sacrificing device strength.

Ex-offenders face many challenges and barriers in obtaining sustainable employment when reentering society. Researchers have demonstrated that participation in a work release program prior to release from prison may be beneficial. However, not all work release reentry programs are alike. Because offenders are the benefactors of these programs, it is essential their experiences are captured. The purpose of this phenomenological study was to understand and describe unique experiences of male ex-offenders previously assigned to a work release program in an urban setting in an Atlantic East Coast state. Bronfenbrenner's ecological systems theory framed the study. This study gives voice to and provides an understanding of the experiences of 5 individuals recruited utilizing the snowball method who were seeking employment while in the work release program. Data was analyzed using Moustakas' 7-step data analysis procedure. Findings may inform program and policy makers of the importance to provide a more robust work release program that includes job readiness support and resources and the need to establish a partnership with local employers. Four themes emerged including: (a) Lack of Resources, (b) Need for Outside Support System, (c) Perception of Lack of Empathy from Correctional Officers and Employers, and (d) Gratitude and Appreciation to Participate in the Work Release Program. Findings further support the importance of collaboration between the criminal justice system, transitional reentry programs and employers in order to achieve positive social change with successful outcomes. These findings may lead to a reinvestment of resources and restructuring of reentry programs to serve its beneficiaries.

This research examined the use of compassionate release policy in response to the fastest-increasing segment of the prison population- elderly offenders. Though this policy is an approach to this problem, there was little available research regarding which correctional organizations in the United States adopt compassionate release and how it is used. The purpose of this nonexperimental comparative quantitative study was to examine the use of the policy in neighboring and distant state correctional systems relative to those organizations that used the policy more frequently to determine if the leader-laggard theory of policy diffusion was an effective policy-implementation framework. The research questions were structured to determine if there was a significant difference between the use of compassionate release policy in state and federal prisons and if there was a significantly higher concentration of policy use in states directly neighboring those where the policy was used more-frequently. Data were collected from 31 state and federal correctional agencies' publicly-available records regarding compassionate release policy use. Data were analyzed using a test of differences for the first research question and independent-samples t-tests for the second research question. The results suggested that there was significantly higher use of the policy by state correctional organizations compared to the federal prison system and that there were not significant differences in policy use between neighboring and distant states of high-use policy areas. Implications for positive social change include informing prisons about processes that may assist in reducing organizational costs and increase safety of elderly offenders, correctional workers, stakeholders, and community members/taxpayers.

The increasing recidivism rate for African American female offenders is exacerbated by postrelease job candidates' difficulties with interviewing for employment. The purpose of this hermeneutical, phenomenological study was to examine experiences from postrelease, African American, female, opioid offenders when interviewing with potential employers. Critical race Black feminist theory was used as the ontological lens for this research. Criterion sampling was used to recruit 12 female African American opioid female research participants. Data collection occurred via 12 semistructured, face-to-face interviewees. Thematic analysis was used to develop common emergent themes from the lived experiences of postrelease, African American, female, opioid offenders. Results showed that postrelease, African American, female offenders experienced emotional responses such as stress, nervousness, and anxiety during the interview process. In addition, they feared rejection when informing potential employers about their criminal background. The findings are significant in developing training programs for transition, human service, and criminal justice agencies that can increase the chances of postoffender, African American, female, opioid drug offender employment and decrease recidivism.

Arsenic (As), a known carcinogen, is a groundwater contaminant in many parts of the world. Arsenic contamination is enhanced through carbon addition, such as biostimulation, a remediation process, which has been used to remove trichloroethylene (TCE) from sediment and groundwater. Two studies were designed to evaluate the effect of different carbon sources on the removal of TCE through dechlorination and on As solubilization and mobilization in response to carbon addition. The first set of columns (15.2 cm diameter, 183 cm long) used whey, Newman Zone® standard surfactant emulsified oil, Newman Zone® nonionic surfactant emulsified oil, and no carbon controls as carbon and energy sources and were fed for 7.5 years. The second set (7.62 cm diameter and length) used whey, lactate, and no carbon control as carbon sources with columns being dismantled and analyzed over a 5-month time period. These studies showed that reducing conditions, caused by the carbon sources, was the driving force for As mobilization as As(V) was reduced to the more mobile As(III). Total As mass in the sediment was lost with all carbon treatments within the first study with whey having a greater loss; however, within the second study, both whey and lactate treatments had the same extent of As mass loss over time. The results also indicated that some As could be attenuating with carbonates or other highly soluble minerals.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nutrition and Food Science; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Includes bibliographical references. / by Rajan Sohansingh Bawa. / M.S.

Since the approval of recombinant human insulin in 1982, there has been a growing interest in the use of biotherapeutics, and more particularly of monoclonal antibodies (mAb)-based products due to their multiple advantages compared to small chemical entities. Nonetheless, mAbs also show some drawbacks, one of them being their sensitivity to diverse instability pathways due to their complex structure. Therefore, attention needs to be paid during formulation and storage of such entities. While administration of mAbs using non-invasive routes has been extensively investigated, it still faces several challenges, especially regarding systemic therapy. Thus, parenteral route currently remains the main route of administration for antibodies (Abs). However, frequent injections are required in order to maintain Ab plasma levels into the therapeutic range, which may induce peak-to-trough fluctuations in blood levels due to multiple dosing as well as poor patient compliance. Consequently, methods to increase the half-life of Abs have gained interest over the last decades, and more particularly the use of sustained-delivery systems based on poly(lactide-co-glycolide) acid (PLGA) derivatives. In this work, the spray-drying of a water-in-oil emulsion (w/o) was selected as the formulation technique to produce Ab-loaded PLGA microparticles. Based on the requirement of sustained-release delivery systems, different objectives were set regarding the characteristics of the microparticles, i.e. a drug loading (DL) of at least 20%, a continuous in vitro and in vivo Ab release over a minimum of one month with a limited burst release and the possibility to maintain Ab stability during manufacturing, storage and release. / Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie) / info:eu-repo/semantics/nonPublished

<div>The advent of Patient-Centric therapy demands technologies capable of producing multiple versions of a given product, each tailored for specific segments of the population/individual, but in a time- and cost-effective manner. Prevailing manufacturing methods for oral dosage forms do not easily lend themselves for the transition to the Patient-Centric area. The purpose of this research was to develop a formulation/manufacturing platform technology meeting the flexibility requirements for Patient-Centric formulation and product development for oral dosage forms. The approach is based on the molecular designing and manufacturing of the dosage form. The dosage form consists of a 3D assembly of prefabricated functional modules, each with a specific pharmaceutical performance function. </div><div>The characterization of individual modules showed that solvent casting produced API-loaded HPMC films with homogeneous content distribution. The release profile of 3D assemblies was significantly influenced by the physicochemical properties of single modules. API-loading, thickness, and diameter had a significant effect on the release kinetics. In contrast, the hydrophobicity of the casting substrate did not affect the release kinetics. The initial geometry of the final 3D assembly given by the number of modules and their diameter was proved to have a significant impact on the release kinetics as well. </div><div>The 3D assemblies were used to produce dosage forms with customizable release profiles. Two API-loaded thin HPMC-based films with fast (FRA) and slow (SRB) release rates were produced by the solvent casting method. Accurate dose control (API loading) was accomplished by varying the number of individual modules in the 3D assemblies, whereas control of release kinetics was achieved by combining different ratios FRA and SRB film modules in the assembled dosage form. </div><div>The modular design was also tested for its ability to generate a dosage form of a weak-base API. This part was accomplished using a module containing citric acid (CA) interspaced between weak-base loaded FRA modules. Characterization of the 3D assemblies that were devoid of CA modules showed that the API release rate from modular assemblies containing weekly basic API exhibited strong pH-dependence. The 3D assemblies featuring CA modules in their design exhibited nearly pH-independent release kinetics. </div><div>Electrospinning was used as an enabling technology to produce HPMC-based fibrous films. HPMC films were able to encapsulate a wide variety of APIs with different aqueous solubility. All fibers produced were in the range of a few hundred nanometers to a few microns. X-ray diffraction and differential scanning calorimetry exhibited the amorphous or crystalline state of the API dispersed. Disintegration and release tests showed the fast dissolution of the fibrous system. </div><div><br></div>

No description available.