bluuebunny/crossref_metadata_2025 huggingface dataset:
The pathology and treatment of children in foster care
Authors:   , Blaine Christine L.
Published: July 2024

Despite the growing numbers of children in foster care placements and the increasing incidence of foster children in psychological treatment, the topics of the pathology and treatment of this special population are strikingly underrepresented in research and scholarly writings. Reasons for inconclusive research results on foster children are suggested: (1) heterogeneity of the population; (2) multiple placements which undermine longitudinal study; (3) confounding historical factors, such as abuse and neglect; and (4) the devastating emotional reactions of psychologists to the foster child's overwhelming loss and chaotic life situations. Some active research by clinicians has identified severe ego pathology among this population, including: lowered IQ, developmental delay, social maladjustment, learning disabilities, school maladjustment, suicidality, primitive defenses, and pathological object relations. A review of the literature on maternal deprivation and children with surrogate parents suggests that foster children are a subset of maternally deprived children, suffering much of the same symptomatology due to deprivation, but their symptoms may be exacerbated and extended in time due to ongoing and repeated losses. The life situations of foster children inherently prevent them from establishing a secure relationship with a psychological parent-that is, an exclusive, and permanent attachment to a caretaking figure. A Dynamic Development Interaction approach to assessment and treatment may prove most efficacious in therapy with foster children because it encompasses biological, emotional, and environmental factors, and their mutual interactions. Goals of therapy with foster children include helping him (1) grieve his losses without repeating them; (2) establish new and secure attachments; and (3) improve ego functioning. Clinicians must be aware of (1) psychological issues of the child; (2) psychological issues of his natural parents; (3) issues of the surrogate parents; (4) workings of the child welfare system; and (5) the therapist's own countertransference issues.
Immunogenetic studies on the mechanisms of host resistance against experimental vaginal candidiasis
Authors:   , Mulero-Marchese Rocio de Lourdes , Blank Kenneth J
Published: July 2024

The roles that peripheral and local cell mediated immunity play in protection from vaginal infections remain unknown. The goal of the studies presented in this thesis is to identify genetic loci and the functions regulated by these loci that are important in determining resistance to vaginal infections with Candida albicans after peripheral immunization. Both BALB/c and C57BL/6 (B6) strains of mice mount a protective immune response against vaginal candidiasis after an intravaginal immunization. In contrast, the protective effects of peripheral immunization against a subsequent vaginal infection appear to be strain-dependent. Significant protection against vaginal candidiasis after a subcutaneous immunization with C. albicans extract was achieved in BALB/c and (BALB/c X C57BL/6)F1 mice but not in B6 mice. Protection from vaginal challenge after peripheral immunization in BALB/c mice is mediated by a secondary immune response associated with a CD4, but not CD8 population of T cells. The ability of F1-derived immune cells to transfer protection to naive parental strains was obvious in BALB/c recipient mice, but much less apparent in B6 recipient mice. Cells derived from F1 immunized mice were able to be traced into the vaginal mucosa of BALB/c mice but not B6 mice. These results are highly suggestive that the microenvironment of the B6 mouse is at least in part responsible for the susceptible phenotype. Linkage analysis using CXB recombinant inbred strains, and (BALB/c X C57BL/6) X C57BL/6 backcross mice revealed that the intercellular adhesion molecule-1 (ICAM-1) and the Icam-1 related sequence 1, are strong candidate genes for controlling resistance to vaginal candidiasis after peripheral immunization. Thus, it appears that the ability of cells to bind to vaginal endothelial cells may play an important role in protection mediated by peripheral immunization. These results may contribute to the understanding of host genetic factors controlling the immune response to vaginal infections.
Murine bone marrow stromal cells
Authors:   , Kopen Gene C. , Prockop Darwin J
Published: July 2024

In adult bone marrow, hematopoiesis is modulated by both direct, cell-cell contact with stromal cells, and by the chemokines and extracellular matrix that they elaborate. In addition to their role in supporting hematopoiesis, bone marrow stromal cells have also been shown to represent a unique population of pluripotent progenitors of non-hematopoietic connective tissues. Friedenstein et al. (1966&1970) first showed that stromal cells could be separated from blood-forming cells by their propensity to adhere to tissue culture plastic and then differentiated into cells of the osteogenic lineage. He later showed (Friedenstein et al. 1987) that this osteogenic precursor derived from the fibroblast-like marrow stromal cell (MSC). Since then, many others have extended Friedenstein's original observations to show that MSCs can also be differentiated into cartilage, fat, and muscle. Because of the plasticity of these cells and the ease by which they can be isolated form posterior iliac crest and expanded ex vivo, MSCs have become an attractive vehicle for cell and gene therapy. Our lab has spent the last several years characterizing the growth and differentiation potential of both murine and human MSCs. We have found however, in agreement with others, that while plastic adherent, human bone marrow cultures result in a relatively pure fraction of MSCs after several passages (Phinney et al. 1999b), murine explants yield cultures that are complex in composition and often difficult to enrich for MSCs by serial passage alone. We have also shown that the yield and growth kinetics of MSCs in standard liquid cultures vary significantly even between different inbred stains of mice. These limitations have, therefore, hampered progress in developing murine models by which to study both the in vitro and in vivo potential of these cells. As a result, we have devised a simple isolation procedure for generating a highly enriched fraction of murine MSCs that can be differentiated in vitro into osteocytes, chondrocytes, and adipocytes, and in vivo into osteocytes and astrocytes.
Behavioral analysis of putative antipsychotic actions at serotonin and dopamine receptors
Authors:   , Scarlota Laura , Harvey John A
Published: July 2024

Schizophrenia is a debilitating mental disorder affecting approximately 1% of the population. Current antipsychotics can manage positive symptoms, and, to a much lesser extent, negative, cognitive and affective symptoms. All antipsychotics on the market bind to dopamine receptors and often their efficacy is attributed to receptor antagonism; however, accumulating evidence has suggested that further benefits and fewer side effects may be derived from altering dopamine levels. One possible way to achieve this effect is through serotonin-2 (5-HT2) receptor inverse agonism, which has been shown to modulate dopamine release. Therefore, the goal of this project was to evaluate the antipsychotic potential of 5-HT2 receptor inverse agonism. First, using radioligand binding, 5-HT2 receptor agonists, antagonists, and inverse agonists were classified according to their effects following chronic treatment (i.e. agonists down-regulate and inverse agonists up-regulate receptors). Then, the 5-HT2A/2C receptor inverse agonist, SR46349B, was selected for subsequent behavioral analysis. The first study investigated the effects of SR46349B on hallucinogen-elicited behavior as a rabbit model of psychosis. After hallucinogen administration, the frequency of a motor behavior (head bob) was measured. SR46349B significantly reduced hallucinogen-elicited behavior suggesting it may diminish psychosis. Following this, we tested the effect of SR46349B on cognition. In schizophrenia, there is an enhanced response in associative learning, possibly due to an inability to ignore irrelevant stimuli. Therefore, an antipsychotic should disrupt these types of associations. Administering SR46349B during eyeblink classical conditioning reduced acquisition of conditioned responses, thus SR46349B may improve cognitive deficits in schizophrenia. Next, to test anxiety, rabbits were exposed to a novel environment and motor behaviors were measured. SR46349B attenuated the novelty-elicited effects suggesting it may be anxiolytic-like. Finally, we investigated the role of dopamine receptors in SR46349B-elicited behavior given the presumed effect of 5-HT2 receptor inverse agonism on the modulation of dopamine release. Of the two dopamine receptors (D1 and D2), only D1 were found to be involved in the 5-HT2 inverse agonist response. Collectively, these results indicate that 5-HT2 receptor inverse agonism and subsequent D1 agonism can diminish hallucinogen effects, cognitive impairments, and anxiety and thus may manage multiple symptoms of schizophrenia.
Ku80 facilitates chromatin binding of the telomere-binding protein TRF2 and enhances genomic stability in normal human fibroblasts
Authors:   , Koltowski Fink Lauren Sara , Sell Christian
Published: July 2024

The Ku heterodimer is central to non-homologous end joining repair, the predominant pathway in mammals for repair of DNA double-strand breaks. The heterodimer, consisting of Ku70 and Ku80, has also been implicated in chromosome stability and telomere maintenance, and the Ku80 gene appears to be essential for human but not rodent cell survival. Ku associates with a number of proteins involved in various processes, including replication, cell adhesion, and transcription. The diversity of Ku interactions suggests the requirements for Ku in the cell may extend beyond canonical repair. While the role of the Ku heterodimer in DNA repair and immune function are well established, the role of Ku80 in processes beyond DNA end joining, including telomere biology, are not fully understood. Targeting Ku80 leads to a number of telomeric effects that differ somewhat depending on the cell type, suggesting Ku may be differentially required for telomere stability. In order to examine in more detail the role of Ku80 in normal human cells, we have utilized RNA interference using a human fibroblast strain. Following targeted Ku80 knockdown, WI38 fibroblasts undergo rapid growth arrest and display characteristics of senescence with evidence of non-disjunction and telomere abnormalities. The growth arrest and senescence activation seem to be at least partially mediated by p53. In addition, levels of TRF2, a sequence-specific telomere binding protein, are reduced following loss of Ku80, suggesting a critical role for Ku in maintaining the telomere protein complex. Our results suggest that the Ku heterodimer enhances TRF2 chromatin association and that non-chromatin bound TRF2 is targeted to the proteasome. Taking into consideration these novel results as well as the reported functions and ubiquitous expression of Ku, we propose a fundamental role for the Ku heterodimer as a docking site for TRF2 at the telomere. We also address the potential role for Ku in species-specific responses to damaged chromatin, suggesting a novel function for Ku in cellular communication. The enhanced association of a sequence-specific DNA binding protein through association with the Ku heterodimer provides a potential model to explain the requirement for Ku in multiple cellular processes.
The Mechanism of Interleukin-5 Receptor Assembly and Activation as Determined by Fluorescence Resonance Energy Transfer Imaging
Authors:   , Zaks-Zilberman Meirav , Chaiken Irwin , Jameson Bradford Aldrich
Published: July 2024

The hematopoietic cytokine Interleukin-5 (IL-5) orchestrates its functions through binding to a cell surface receptor complex consisting of two transmembrane subunits, a specific ligand binding [alpha] subunit and a signal transducing [beta]c subunit that is shared between IL-3, IL-5, and GM-CSF. The assembly mechanism of the receptor that leads to activation is flot fully understood. In this thesis, fluorescence resonance energy transfer (FRET) imaging is used as a technique to clarify the details of receptor organization and to characterize the physical interactions between IL-5 and its cognate full length receptor subunits within the context of an intact membrane. We find that [beta]c is a preformed homo-oligomer that undergoes hetero-oligomerization and/or further conformational changes upon the binding of IL-5. Additionally, at least two a subunits are present in IL-5· IL-5R[alpha]· [beta]c complexes upon activation. We also find that an intact hetero-oligomeric complex is required to recruit the new [alpha]-chain(s) to the receptor complex. The IL-5 induced recruitment of a new a subunit(s) to the high affinity complex may provide a means of mediating the final intracellular receptor signals. Together these findings support the sequential assembly model of IL-5 receptor activation whereby IL-5 triggers cellular responses by binding first to the specific [alpha] receptor, followed by binding of the ligand-specific a complex to [beta]c; this then leads to conformational changes and/or higher order oligomerization formation of [alpha] and [beta]c. These studies uniquely contribute to the current understanding of the molecular interactions of the IL-5 ligand-receptor system during receptor assembly and activation by presenting new evidence of the intracellular rearrangements of the full length receptor in an intact cellular environment and in response to ligand-binding. These results can help elucidate the structural basis of signal specificity and amplification utilized by Class I cytokine receptors, and may eventually lead to novel therapeutic interventions in pathophysiological signaling by these cytokines.
Chlamydia pneumoniae
Authors:   , Arking Edward James , Balin Brian J
Published: July 2024

The following work was completed in order to assess whether the intracellular bacterium Chlamydia pneumoniae was present in post-mortem brain samples from patients with and without late-onset Alzheimer's disease (AD), since some indirect evidence seemed to suggest that infection with the organism might be associated with the disease. Nucleic acids prepared from those samples were screened by PCR assay for DNA sequences from the bacterium, and such analyses showed that brain areas with typical AD-related neuropathology were positive for the organism in 17/19 AD patients. Similar analyses of identical brain areas of 18/19 control patients were PCR-negative. Electron and immunoelectron microscopic studies of tissues from affected AD brain regions identified chlamydial elementary and reticulate bodies, but similar analyses of non-AD brain tissues for C. pneumoniae were negative for the bacterium. Culture analyses of a subset of affected brain tissues for C. pneumoniae were strongly positive, while identically performed analyses of non-AD brain tissues were negative. RT-PCR assays using RNA from affected areas of AD brains confirmed that transcripts from two important C. pneumoniae genes, ompA and 16S rRNA, were present in those samples but not in controls. Immunohistochemical examination identified C. pneumoniae within pericytes, microglia, and astroglia in AD brains but not in controls. Further immunolabeling studies confirmed the organism's intracellular presence primarily in areas of neuropathology in the AD brain. In situ hybridization revealed that pericytes and glial cells in areas which demonstrated AD pathology were immunoreactive with the probe while those areas without neuropathology were not immunoreactive. Thus, C. pneumoniae is present, viable, and transcriptionally active in areas of neuropathology in the AD brain, suggesting that infection with the organism is a risk factor for late-onset AD. (Abstract shortened by UMI.).
An integrated model of prefrontal cortex processing. Neurocognitive mechanisms underlying prefrontal cortex processing in human behavior
Authors:   , Menahem Mazal
Published: July 2024

An integrative, theoretical, interdisciplinary approach is adopted to understand prefrontal cortex processing. This approach can provide a solution to specific problems posed by neuropsychology, cognitive psychology, cognitive neuropsychology, cognitive neuroscience, neurophysiology and neurophilosophy. Several theories of prefrontal cortex processing are reviewed. These theories are either too general or too narrow. They are all developed empirically and suffer from biases of both subjects and procedure selection. Goldman-Rakic's (1987a) cognitive/behavioral explanation for the prefrontal cortex processing provides a comprehensive analysis of the neuroanatomy and the neurophysiology of the prefrontal cortex. Norman and Shallice (1986) developed a cognitive theoretical point of view, which was later applied to the prefrontal cortex. The integrated model uses the neurophysiological analysis of Goldman-Rakic with data from PET studies. Several principles of the cognitive aspects of the integrated model are adopted from the model of Norman and Shallice. Only those elements that can be explained by neural mechanisms are incorporated. The integrated model perceives the human being as an active self-regulative organism who participates in constant interaction and transaction with the environment. In routine behavior, schemas elicit an automatic response without the need for further attentional/conscious recourses of the prefrontal cortex. When the automatic process fails, further attentional recourses, mediated by the prefrontal cortex, are needed. The integrated model suggests five neurocognitive mechanisms underlying this process, including an emotional/motivational network that mediates prefrontal control over emotional effects. The five networks connect the prefrontal cortex to other regions in the brain. These networks work together, in parallel, affecting different aspects of schemas at the same time. The integrated model can better explain behaviors in normal and disturbed subjects. ADHD, which recently was considered as a prefrontal disorder, is explained by different disturbances in the five neurocognitive networks suggested by the integrated model. The specification of mechanisms, provided by the model, goes further ahead than other suggested general accounts that underlie prefrontal disorder in ADHD.
A psychological model for understanding musical development
Authors:   , Briggs Cynthia Anne , Levick Myra F.
Published: July 2024

This dissertation is structured to begin placing the research related to musical development into a model that integrates musical research with accepted models of early child development. Using the work of Anna Freud, Margaret Mahler, Jean Piaget and Paul Kegan, emphasis is placed on current theories of psychosexual development and on the constructive-developmental models. The interpersonal model, created by Daniel Stern, is also included to emphasize further preverbal psychology and its importance in musical development. These models are used as a framework for illustrating when milestones in music development occur relative to other developmental events. Following the integration of the research in music and child development, the author examines what the implications are for each element of musical development relative to when it occurs and the known parameters of each developmental period. A model for musical development created by the author is then presented. Application of the model to clinical assessment and treatment is discussed.
The effect of therapeutic alliance on perceived levels of formal and informal coercion
Authors:   , Lareau Craig R. , Heilbrun Kirk
Published: July 2024

Numerous studies have examined the role of coercion to affect mental health and substance abuse treatment entry, but only recently have researchers begun to examine the role of perceived coercion to enter treatment, which encompasses not only legal forms of coercion, but also non-legal coercion and pressures from family, friends, and others in the community. Therapeutic alliance is a concept that has been studied concerning treatment retention and outcome, but which has not been studied in relation to its effect on perceived coercion to enter treatment. This study examines differences between legally mandated and non-legally mandated patients on levels of perceived coercion to enter substance abuse treatment, as well as the effect of the therapeutic alliance on altering intake levels of perceived coercion. Participants were 69 males with a mean age of 33 years entering drug treatment into two treatment sites in Philadelphia that accept both legally mandated and non-legally mandated patients. Participants included 47 legally mandated and 22 non-legally mandated patients, who were tested at treatment intake for levels of both perceived coercion and procedural justice, and who made prospective assessments of later therapeutic alliance. Approximately six weeks into treatment, the 39 remaining participants were tested again on actual levels of therapeutic alliance, and reassessed for levels of perceived coercion and procedural justice. ANOVAs were used to test for differences between the legally mandated and non-legally mandated participants on the intake measures. Intake results revealed that legally mandated and non-legally mandated participants differed significantly on intake levels of perceived coercion, but did not differ on prospective assessments of therapeutic alliance. Comparison of two perceived coercion instruments revealed the Survey of Treatment Entry Pressures is more sensitive to detecting nonlegal sources of coercion than the MacArthur Admission Experience Survey. Correlational analyses performed on the data collected six weeks later revealed that changes in levels of therapeutic alliance were negatively correlated with changes in levels of perceived coercion, and positively correlated with changes in levels of procedural justice. Implications for drug treatment policy are discussed and directions for future research are proposed.
The potential of human bone marrow stromal cells as vehicles for ex vivo gene therapy applications
Authors:   , DiGirolamo Carla Marie , Prockop Darwin J
Published: July 2024

The bone marrow stroma, is postulated to contain multipotential, mesenchymal progenitors capable of differentiation into osteoblasts, adipocytes, chondrocytes, and myoblasts. These properties make marrow stromal cells (MSCs) attractive candidates as vehicles for gene therapy of various diseases. However, much of these data characterizing MSCs are derived from animal models, with knowledge of the human marrow stromal system slowly emerging. In our efforts to characterize human bone marrow stromal cells (hMSCs), we analyzed the growth and differentiation properties of hMSCs obtained from iliac crest aspirates of normal human volunteers. We show that hMSCs are heterogeneous with respect to morphology, differentiation capacity, and growth dynamics. We also identified a subpopulation that is enriched in highly proliferative, multipotential mesenchymal progenitors based on a simple colony forming unit assay. Analysis of this population revealed that the proliferative potential of these cells increases dramatically at low density relative to higher plating density. Furthermore, we demonstrate that low density propagation enriches hMSC cultures for colony forming cells. We conclude that the mesenchymal progenitors reside within the colony forming population of adherent cultures and that progentior cells exist at different stages of differentiation. When MSCs are propagated in vitro, inhibitory factors that limit lifespan and colony forming potential appear to be present at high density, but not evident at lower density. These findings have significant implications for the biological phenomena occurring under various conditions. Furthermore, exploiting the proliferative capacity of hMSCs by low density propagation is significant for ex vivo expansion to obtain adequate numbers for genetic manipulation and therapeutic use. Finally, we developed an ex-vivo gene therapy strategy for osteogenesis imperfecta (OI) utilizing hMSCs genetically engineered with the wild type [alpha]1 chain of type I procollagen (COL1Al). We designed a COL1A1 cDNA construct that expresses an appropriate transcript in transfected HT1080 cells. We also devised a strategy to assay expression of COLlA1 in hMSCs. These studies are the first step in determining the feasibility of using modified hMSCs in future clinical trials for OI.
Capital Punishment for Mentally lll Offenders
Authors:   , Pich Michele , Goldstein Naomi E
Published: July 2024

In recent years, several landmark cases have excluded groups of offenders from capital punishment eligibility on the basis of diminished capacity and evolving standards of decency. The current study examined data from 203 university students to examine the evolving standards of decency regarding death penalty eligibility for individuals with mental health diagnoses. Participants were provided with one of four case vignettes, which varied only by mental health diagnosis, and asked to sentence the defendant in the vignette to death or to life in prison without the possibility of parole. Results revealed that sentencing decision differed by diagnosis; participants sentenced the defendant with Paranoid Schizophrenia less harshly than they did the defendants with Bipolar I Disorder without psychotic features, Generalized Anxiety Disorder, and no mental health diagnosis. Perceived level of responsibility for the crime did not significantly mediate the relationship between diagnosis and sentencing decision.
Behavior of steel built-up grinders with corrugated webs
Authors:   , Seshadri Anand
Published: July 2024

In order to reduce the weight and cost of structural steel beams, it has been customary to use thin webs. Welding intermediate vertical stiffeners has been the conventional solution to improve the out-of-plane stiffness of the web and prevent its early buckling. Apart from costing up to 50% of the price of the beam, welding the stiffeners also reduces its fatigue life. Adequate out-of-plane stiffness of the web, without welding stiffeners or using a thick material, can be achieved by using corrugated webs. With the advances in the welding technology, corrugated webs can be easily welded to the flanges and are thus an economical and a viable alternative. Though some experimental investigations have been conducted on beams with corrugated webs in Europe and more recently in the United States, and methods developed to predict their ultimate capacity under different static loading conditions, these methods are limited to the tested corrugation configurations. Though testing is ideal, it is nearly impossible to study the effects of all the relevant parameters by testing since tests are expensive and time consuming. Using finite element analysis, a comparatively in-expensive analytical tool, and testing, the behavior of beams with trapezoidally corrugated webs has been studied under different static. loading conditions and simple methods have been developed to predict their ultimate shear, bending, and edge loading capacities. Under shear, webs with a coarse corrugation fail due to local buckling while those with a comparatively dense corrugation fail in a global buckling.
Mechanisms of antifungal drug resistance in Candida species
Authors:   , Raj Shriya , Edlind Thomas D
Published: July 2024

Candida albicans and the recently emerged Candida glabrata are the most frequent agents of opportunistic fungal infection. Antifungals commonly used to treat these infections inhibit synthesis of the cell wall or plasma membrane. These agents are, respectively, the [beta]-1,3-glucan synthesis-inhibiting echinocandins (e.g., caspofungin) and the ergosterol biosynthesis-inhibiting azoles (e.g., fluconazole). In C. albicans, [beta]-1,3-glucan synthesis is linked to essential gene GSC1, the site of mutations conferring high-level echinocandin resistance. In mutants exhibiting low-level resistance, expression of GSC1 paralog GSL2 was upregulated. To further study its role, the UAU1 technique was employed to generate homozygous gsl2 disruptants. One of four disruptants obtained, D4, was caspofungin-hypersensitive. Furthermore, D4 demonstrated an osmostabilizer-suppressed growth defect, hypersensitivity to cell wall-binding agents calcofluor white and congo red, and temperature sensitivity, consistent with a role for GSL2 in cell wall integrity. Intriguingly, GSL2 expression was highly growth-phase dependent - abundant in early to mid-log and declining in late log - suggesting a role during rapid cell wall growth. Intrinsic and acquired azole resistance in C. glabrata is mediated by transcription factor Pdr1-dependent upregulation of azole/multidrug transporter gene CDR1. The CDR1 promoter contains six candidate Pdr1 response elements (PDRE) located 133 to 1200 bp upstream of the start codon, followed by a GGAYYT repeat and a candidate TATA box. To analyze the role of these elements, a PCDR1-TRP1 plasmid reporter system was developed in conjunction with trp1[delta] strains encoding either wild type or constitutively active Pdr1 from azole-resistant mutant F15. TRP1 expression was monitored by evaluating growth on or in trp-minus medium. Truncation analysis revealed that five PDRE are required for full TRP1 expression in Pdr1WT and three in Pdr1F15 cells. In a 4 PDRE construct, TRP1 expression in Pdr1F15 cells was progressively reduced when 1 to 3 PDRE were mutated. Mutational inactivation of the TATA box only modestly reduced TRP1 expression. Interestingly, mutation of the GGAYYT repeat eliminated expression in Pdr1WT but had no effect in Pdr1F15 cells. In summary, these studies characterized new factors that play a role in echinocandin and azole activity, and suggest new ways in which this activity may be enhanced.
Anti-symmetric coherent anti-Stokes Raman scattering from micron sized water droplets
Authors:   , Khambatta Noshir Minocher
Published: July 2024

This work presents the computations of the coherent anti-Stokes Raman scattering (CARS) from water droplets. The nonsymmetric 3430 cm('-1) line of water was chosen for the Raman resonance mode. To determine the CARS field, two plane waves are allowed to fall on the water droplet. As a result two internal Mie fields arise. The source for the CARS field is the third-order electric polarization vector arising from the third-order interactions of the internal fields. In general for isotropic media the third-order polarization vector retains only the components X(,1122) and X(,1221) of the third-order nonlinear optical suceptibility tensor. For a symmetric line, which has no depolarization ratio, only the X(,1122) term is needed. Water has a finite depolarization ratio of 0.2, so that both the terms are now important for the computations of the CARs field. Our results show that for water, the CARS scattered fields for a nonsymmetric line are significantly different from the CARS scattered fields for a symmetric line of a material in droplet form. This difference is brought about in part by polarization scrambling. For a symmetric line polarization scrambling of the internal fields comes about solely through the agency of morphological scrambling. That is the change of polarization of the internal fields relative to that of the input fields comes about because of the need for the fields to obey the boundary conditions over the surface of the droplet. For the 3430 cm('-1) line of water, the line anistropy itself contributes further to the polarization scrambling. Thus the difference in the polarization of the field scattered by a water droplet without and with the depolarized components of the line are polarization scramblings not due to droplet morphology alone, but arise from the instrinsic nonsymmetric properties of the particular line.
The best of times
Authors:   , Weil Ann Marie , Reisman Fredricka K
Published: July 2024

In the course of a lifetime, four of every five American families will be touched by a stroke, and yet most people still think of stroke as an illness that strikes the very old. This misconception makes the stoke phenomenon an almost invisible, misunderstood, and underrated medical crisis. The methodology of autoethnography gives this researcher the opportunity to narrate the details of her own cerebral vascular accident (CVA) or stroke, giving medical personnel, caretakers, and other stroke survivors a look into the personal and cultural implications of the stroke experience. Of particular significance is the concept that a new identity must be formed after a stroke. The researcher, previously the Associate Dean of Lifelong Learning at Drexel University, has chosen to give the title true-life meaning and learn to live life in a new way.
Fabry-Perot waveguide modulator with nano-photonic distributed mirrors
Authors:   , Zubrzycki Walter J. , Herczfeld Peter R
Published: July 2024

The next step towards photonic integration will require miniaturization of components and devices. The work presented in this thesis is directed towards developing a technology to realize nano-structure reflective components for a Fabry-Perot modulator device application. Included is the design of the modulator, analysis of nano-structure etch dynamics, and experimental evaluation of the grating devices. Components, such as periodic nano-photonic reflecting structures will assist in reducing the size of devices, such as lasers, filters, couplers, and modulators. Existing integrated-optic mirror technology employs shallow-etched distributed Bragg reflectors embedded in the semiconductor structure, requiring epitaxial regrowth to complete the structure. This approach typically results in long grating regions to attain high reflectivity. The Fabry-Perot modulator is designed to maintain single-mode performance from a ridge waveguide 2.0 [mu]m wide and 0.78 [mu]m tall. The overall device length is less than 435 [mu]m, which includes two 80% reflective-150 [mu]m long grating regions and a 135 [mu]m long cavity. Electric-field induced phase modulation changes the state of the resonant cavity, resulting in an intensity modulated optical output. The gratings are designed to eliminate epitaxial regrowth by etching deep trenches into the waveguide. The critical geometry required a squarewave profile, with vertical sidewalls, flat bottoms, and squared corners. The grating trench etch measured 100 nm wide across a 2.0 [mu]m wide ridge waveguide with a maximum depth of 800 nm. The modulator device was realized following successful grating fabrication development. The Fabry-Perot concept was verified with a modulation bandwidth less than 100 kHz, limited by excessive parasitics from a large probe pad and test instrumentation. The etch technology developed to fabricate the gratings was extended to two-dimensional nano-photonic post realization. Although high aspect-ratio etches have been performed in an Ion Beam Assisted Etching system, this is the first known analysis of Reactive Ion Beam Etching directed towards nano-photonic post applications. This work contributed to the development of next generation nano-photonic reflecting components which are expected to make the current distributed Bragg reflector technology obsolete.
Sexually abused children and their parents
Authors:   , Sudler Nanette Cheri , McGuffin Patrick W.
Published: July 2024

Child sexual abuse (CSA) has existed throughout recorded history and has been referred to in mythology. Today, CSA affects many children and families throughout the world and is a prominent concern to healthcare professionals and the community at large. A few treatments have been found to help children who have been sexually abused, however, the burgeoning research dealing with CSA has not fully developed. The purpose of this study is to examine children and caregivers' perceptions related to issues regarding participation in psychotherapy for children who have had experiences of sexually abuse. Data were collected from two sites, Joseph J. Peters Institute (JJPI) and the Center for Children's Support (CCS). Both centers focus on the psychological treatment of children who have been sexually abused. Seventy-one families who had contact with either site between 1986 and 1994 participated in the study. The families were interviewed and asked various questions pertaining to their perceptions of their experiences with psychotherapy. Demographic information was collected and some information was obtained from previous files. Each family received $100.00 in compensation for their time and efforts. Once the data were obtained, the SPSS PC+ statistical program was used to analyze the data. Results indicated that, overall, the subjects had positive views of their psychotherapy experience and perceived benefit from it. The children and caregivers' perception were more similar than dissimilar. The focus of therapy was found to be an important factor related to satisfaction with therapy. Several reasons for discontinuing therapy were found. When attempting to discriminate between people who continued in therapy and those who discontinued, internal perceptions and external conditions were not found to be helpful in differentiating the two groups. The results are discussed in relation to the existing literature and directions for future research are suggested. This was an exploratory study and the results should be interpreted with much caution due to the sampling bias.
The Use of a Dual Microbalance-Calorimeter Apparatus in the Characterization of Water Sorption in Polylactide-Derived Materials
Authors:   , Meisner Joshua Adam , Cairncross Richard Allan
Published: July 2024

This thesis demonstrates the use of the quartz crystal microbalance/heat conduction calorimeter (QCM/HCC) in obtaining data that sheds light on the sorption of water into polymer films. Subsequently, it describes the application of this device towards the investigation of the effects of chemical and physical modifications on the sorption properties of polylactide, a biobased polymer. This project is par of an overall research program seeking to improve the moisture barrier properties of polylactide while maintaining its desirable properties of biodegradability and being predominantly derived from renewable feedstocks. The Quartz Crystal Microbalance/Heat Conduction Calorimeter (QCM/HCC) is a new instrument that is capable of concurrently measuring very small changes in mass and releases of heat. Moisture sorption into a material results in changes in its microscopic conformation that can be quantified through the measurement of the heat released or absorbed over the term of the process. The QCM/HCC is capable of obtaining these two measurements and correlating them to external vapor activity in order to produce sorption isotherms and thermodynamic data. There has recently been increased interest in bio-based polymers as a replacement for a portion of the petroleum-based polymers that are commonly used in present-day society. The utility of such polymers has been hindered by their tendency to take up water, which precludes their extended use. It is desirable to develop polymers produced primarily from biological feedstocks that retain their biodegradability while exhibiting improved moisture barer properties. This thesis presents an experimental set-up centered around the QCM/HCC that demonstrates the effectiveness of the device in efficiently obtaining mass uptake and heat evolution data that quantify the effects of water sorption on a polymer film. It then provides data on the effects of the addition of hydrophobic additives to polylactide through both copolymerization and physical blending. Sorption data on PLA films demonstrate an increasing enthalpy of sorption that gradually approaches the value of the enthalpy of vaporization of water, indicating the clustering of water molecules within this polymer, in contrast to similar data on films of the more hydrophilic PHEMA, where the enthalpy of sorption is significantly lower. Although blending polylactide with poly(dihexadecylglycolide) results in a decreased solubility, the amount of the more hydrophobic component that must be added to produce a significant change is prohibitive. Copolymerization with poly(dihexadecylglycolide) appears to be a more promising technique for changing the moisture barer properties of polylactide.
IPv6 Compression Techniques and Performance
Authors:   , Measel Ryan Thomas , Kam Moshe
Published: July 2024

The adoption of IPv6 over its predecessor IPv4 has been a slow process despite that IPv6 offers many advantages is terms of flexibility, security, and routing in addition to a vastly larger addressing space. The disadvantage is that IPv6 needs a larger header size as well to provide these features. A great amount of overhead accumulates for IPv6 transmissions with small packet sizes, such as network management and resil-time trafiSc. Several header and payload compression techniques have been proposed to mitigate this effect. In this paper, the various compression techniques are identified said evaluated. A testbed.was devised to further investigate a select set of protocols. TVafiic shaping was vised to impose non-ideal network constraints, such as delay, packet loss, and bit error. It was shown that header compression is highly effective at reducing overhead, especieilly for small packet sizes. RObust Header Compression (ROHC) was foimd to perform the best under network constraints with the exception of packet reorderings. Payload compressions techniques were less useful as they require overhead in the form of either a per-packet dictionary or a synchronization mechanism, and the data payload cannot be previously compressed or encoded.
Development and investigation of failure mechanism of interlocking mortarless block masonry systems
Authors:   , Oh Kang-Ho , Harris Harry George
Published: July 2024

Interlocking mortarless or "dry stacked" masonry construction represents an attractive alternative to conventional block masonry with mortar joint construction. The attractiveness of increased construction efficiency with potentially less skilled labor and thus lower costs accounts for the worldwide interest that has been shown for this new masonry construction technique. The present study examines the potential use of the interlocking mortarless blocks by performing both experimental and analytical investigations. Two different types of interlocking mortarless blocks have been physically modeled at 1/3 scale and small masonry assemblages were tested under compressive, shear, and flexural loads. Structural performance was compared to similar conventional block mortar jointed specimens fabricated by the same laboratory techniques. Results showed that the failure mechanism has been altered due to the lack of joint filler material and the resulting progressive contact behavior at the dry joints. Thus, a focus has been made on the effect of the geometric imperfection at the bed joints to the structural behavior of the mortarless masonry under axial compression. A three dimensional nonlinear finite element model is developed in the ANSYS general purpose FEM environment. The required FEM input data including uniaxial stress-strain relations, nonlinear localized contact stiffness, frictional behavior, and geometric properties were determined by extensive experimental investigation. Very good agreement between the deformational behavior of the physical and the FEM models has been achieved. Based on the experimental evidence and the stress fields generated by the FEM model, a failure mechanism of the drystacked masonry under compressive load is proposed.
The role of thrombospondin-1 on the regulation of the plasminogen plasmin system and tumor cell invasion
Authors:   , Albo Daniel , Tuszynski George P.
Published: July 2024

Thrombospondin-1 (TSP-1) is a large glycoprotein that localizes to the extracellular matrix in several different tumors. There is a growing body of data demonstrating that TSP-1 plays a critical role in tumor progression and invasion. TSP-1 has been shown to promote tumor cell adhesion, migration, invasion and angiogenesis, crucial steps in the process of metastasis. Metastasis is a complex multistep process that involves the controlled degradation of the extracellular matrix by tumor-associated proteases. While pericellular proteolysis is crucial for tumor cell invasion to occur, excessive degradation of the tumor associated-matrix can destroy the matrix scaffold that tumor cells need in order to migrate and invade. Therefore, it is currently believed that a balance between proteolytic enzymes and their inhibitors must exist in order to localize the proteolytic activity preferentially to the tumor cell surface. This would allow tumor cells to efficiently invade and metastasize. One of the main proteases involved in malignancy is the plasminogen/plasmin system. The proteolytic conversion of plasminogen to plasmin is catalyzed by the urokinase-type plasminogen activator (uPA) and inhibited by the plasminogen activator inhibitor type 1 (PAI-1). Once generated, plasmin is an enzyme with a broad substrate specificity with the capacity to cleave most of the extracellular matrix components. Additionally, by activating inactive precursors of other proteolytic enzymes such as matrix metalloproteinases, plasmin is believed to control an enzymatic proteolytic cascade. Furthermore, plasmin activates inactive precursors of growth factors stored in latent form in the extracellular matrix such as transforming growth factor beta 1 (TGF-[beta]1). These growth factors may then enhance plasmin generation by upregulating uPA and its receptor, uPAR, therefore generating an amplification loop that further enhances pericellular proteolysis. Localization of proteolytic activity to the tumor cell surface by receptors such as uPAR allows for a more efficient and localized plasmin generation and, therefore, may further enhance pericellular proteolysis and tumor cell invasion. The objective of this thesis work was to determine the effect of TSP-1 in the regulation of the plasminogen plasmin system. Furthermore, we sought to determine what role the plasminogen/plasmin system may play in TSP-1-mediated tumor cell invasion. Our working hypothesis was that TSP-I, through regulation of the plasminogen/plasmin system, promoted a controlled proteolysis of tumor-associated matrix and, therefore, promoted tumor cell invasion. The long term goal of our research efforts is to develop new diagnostic and therapeutic tools that would hopefully allow us to diagnose tumors earlier and treat them more efficiently, while minimizing the side effects to the patient. Translating our bench work to the patient's bedside is the ultimate goal of our work.