• A Novel Cell Penetrating Peptide for the Differentiation of Human Neural Stem Cells

      Ma, Weili; Jin, Geun-woo; Gehret, Paul M.; Chada, Neil C.; Suh, Won H.; 0000-0002-4036-8307 (2018-07-09)
      Retinoic acid (RA) is a bioactive lipid that has been shown to promote neural stem cell differentiation. However, the highly hydrophobic molecule needs to first solubilize and translocate across the cell membrane in order to exert a biological response. The cell entry of RA can be aided by cell penetrating peptides (CPPs), which are short amino acid sequences that are able to carry bioactive cargo past the cell membrane. In this work, a novel cell penetrating peptide was developed to deliver RA to human neural stem cells and, subsequently, promote neuronal differentiation. The novel CPP consists of a repeating sequence, whose number of repeats is proportional to the efficiency of cell penetration. Using fluorescence microscopy, the mode of translocation was determined to be related to an endocytic pathway. The levels of β-III tubulin (Tubb3) and microtubule associated protein 2 (MAP2) expression in neural stem cells treated with RA conjugated to the CPP were assessed by quantitative immunocytochemistry.
    • A Rare Case of Primary Anorectal Melanoma and a Review of the Current Landscape of Therapy

      Yeung, Ho-Man; Gupta, Brinda; Kamat, Bhishak; 0000-0002-7188-9738 (2020-08-02)
      Introduction: Anorectal mucosal melanoma (ARMM) is an uncommon and highly aggressive malignancy. Given its rarity, there is insufficient evidence on the optimal medical management which presents as a clinical challenge to its diagnosis and treatment. Treatment of ARMM typically involves a multimodal approach including surgical resection, chemotherapy, targeted therapy and/or immunotherapy. Case Presentation: Here, we present a case of a 78-year-old female who presented with a four-month history of rectal bleeding and bowel incontinence. Ultimately, colonoscopy revealed a mass at the anal verge, and biopsy of the mass showed malignant cells that stained positive for S100, Melan-A and HMB-45, consistent with the diagnosis of malignant melanoma. Molecular testing revealed no BRAF, KIT or NRAS gene mutations. PD-L1 immunohistochemistry showed tumor proportion score of 1%. She underwent abdominoperineal resection with a plan to initiate immunotherapy with an anti-PD-1 checkpoint inhibitor. This case highlights a rare aggressive malignancy and reviews its treatment option, which are mostly extrapolated from its cutaneous counterpart and some derived from a few case reports. Due to its rarity, there is no consensus guideline for the treatment of ARMM.
    • An Implantable Ultrasonically-Powered Micro-Light-Source (µLight) for Photodynamic Therapy

      Kim, Albert; Zhou, Jiawei; Samaddar, Shayak; Song, Seung Hyun; Elzey, Bennet D.; Thompson, David H.; Ziaie, Babak; 0000-0003-1539-1246 (2019-02-04)
      Photodynamic therapy (PDT) is a promising cancer treatment modality that can selectively target unresectable tumors through optical activation of cytotoxic agents, thus reducing many side effects associated with systemic administration of chemotherapeutic drugs. However, limited light penetration into most biological tissues have so far prevented its widespread adoption beyond dermatology and a few other oncological applications in which a fiber optic can be threaded to the desired locations via an endoscopic approach (e.g., bladder). In this paper, we introduce an ultrasonically powered implantable microlight source, μLight, which enables in-situ localized light delivery to deep-seated solid tumors. Ultrasonic powering allows for small receiver form factor (mm-scale) and power transfer deep into the tissue (several centimeters). The implants consist of piezoelectric transducers measuring 2 × 2 × 2 mm3 and 2 × 4 × 2 mm3 with surface-mounted miniature red and blue LEDs. When energized with 185 mW/cm2 of transmitted acoustic power at 720 kHz, μLight can generate 0.048 to 6.5 mW/cm2 of optical power (depending on size of the piezoelectric element and light wavelength spectrum). This allows powering multiple receivers to a distance of 10 cm at therapeutic light output levels (a delivery of 20–40 J/cm2 light radiation dose in 1–2 hours). In vitro tests show that HeLa cells irradiated with μLights undergo a 70% decrease in average cell viability as compared to the control group. In vivo tests in mice implanted with 4T1-induced tumors (breast cancer) show light delivery capability at therapeutic dose levels. Overall, results indicate implanting multiple µLights and operating them for 1–2 hours can achieve cytotoxicity levels comparable to the clinically reported cases using external light sources.
    • An unusual presentation of non-IBD related colorectal primary extranodal diffuse large B cell lymphoma with a colo-colonic fistula

      Temple University. Hospital (2021-09-20)
      Diffuse large B cell lymphoma of the sigmoid colon and rectum is relatively uncommon and aggressive. Due to its nonspecific symptomatology, patients are often diagnosed late into the disease and present with life-threatening complications, such as hemorrhage, obstruction, or perforation, requiring emergent surgical intervention. Patients with colorectal lymphoma typically have inflammatory bowel disease or immunosuppression. We present a case of a 79-year-old male with no known inflammatory bowel disease or immunosuppression, who had significant weight loss, diarrhea, and abdominal fullness, found by CT to have irregular wall thickening of the recto-sigmoid colon along with a colo-colonic fistula, concerning for bowel perforation. Endoscopic evaluation and biopsy confirmed the diagnosis of recto-sigmoid Diffuse large B cell lymphoma, with a PET/CT scan revealing stage IV disease. He had a partial response to six cycles of palliative reduced dose R-CHOP and is currently receiving palliative radiation to the sigmoid colon and rectum. Surgery and/or chemoradiation remain the mainstay therapy for this condition. Clinicians, however, must consider patient's functional, nutritional, and clinical status prior to choosing an optimal therapeutic regimen. This case illustrates a unique clinical presentation of this condition and the associated diagnostic and therapeutic challenges that arise in order to prevent life-threatening complications.
    • Area-based socioeconomic factors and Human Papillomavirus (HPV) vaccination among teen boys in the United States

      Swiecki-Sikora, Allison L.; Stroup, Antoinette M.; Warner, Echo L.; Kepka, Deanna; Henry, Kevin; 0000-0002-5348-9669 (2017-07-14)
      Background: This study is the first to examine associations between several area-based socioeconomic factors and human papillomavirus (HPV) vaccine uptake among boys in the United States (U.S.). Methods: Data from the 2012-2013 National Immunization Survey-Teen restricted-use data were analyzed to examine associations of HPV vaccination initiation (receipt of ≥1 dose) and series completion (receipt of three doses) among boys aged 13-17 years (N = 19,518) with several individual-level and ZIP Code Tabulation Area (ZCTA) census measures. Multivariable logistic regression was used to estimate the odds of HPV vaccination initiation and series completion separately. Results: In 2012-2013 approximately 27.9% (95% CI 26.6%-29.2%) of boys initiated and 10.38% (95% CI 9.48%-11.29%) completed the HPV vaccine series. Area-based poverty was not statistically significantly associated with HPV vaccination initiation. It was, however, associated with series completion, with boys living in high-poverty areas (≥20% of residents living below poverty) having higher odds of completing the series (AOR 1.22, 95% CI 1.01-1.48) than boys in low-poverty areas (0-4.99%). Interactions between race/ethnicity and ZIP code-level poverty indicated that Hispanic boys living in high-poverty areas had a statistically significantly higher odds of HPV vaccine initiation (AOR 1.43, 95% CI 1.03-1.97) and series completion (AOR 1.56, 95% CI 1.05-2.32) than Hispanic boys in low-poverty areas. Non-Hispanic Black boys in high poverty areas had higher odds of initiation (AOR 2.23, 95% CI 1.33-3.75) and completion (AOR 2.61, 95% CI 1.06-6.44) than non-Hispanic Black boys in low-poverty areas. Rural/urban residence and population density were also significant factors, with boys from urban or densely populated areas having higher odds of initiation and completion compared to boys living in non-urban, less densely populated areas. Conclusion: Higher HPV vaccination coverage in urban areas and among racial/ethnic minorities in areas with high poverty may be attributable to factors such as vaccine acceptance, health-care practices, and their access to HPV vaccines through the Vaccines for Children Program, which provides free vaccines to uninsured and under-insured children. Given the low HPV vaccination rates among boys in the U.S., these results provide important evidence to inform public health interventions to increase HPV vaccination.
    • Bacterial Contamination on Latrine Surfaces in Community and Household Latrines in Kathmandu, Nepal

      McGinnis, Shannon; Marini, Dianna; Amatya, Prakash; Murphy, Heather M. (2019-01-17)
      A lack of sanitation infrastructure is a major contributor to the global burden of diarrheal disease, particularly in low-income countries. Access to basic sanitation was identified as part of the 2015 United Nations Sustainable Development Goals. However, current definitions of “basic” sanitation infrastructure exclude community or shared sanitation, due to concerns around safety, equity, and cleanliness. The purpose of this study was to measure and compare bacterial contamination on community and household latrine surfaces in Kathmandu, Nepal. One hundred and nineteen swab samples were collected from two community and five household latrines sites. Community latrine samples were taken before and after daily cleaning, while household samples were collected at midday, to reflect normal conditions. Concentrations of total coliforms and Escherichia coli were measured using membrane filtration methods. Results found almost no differences between bacterial contamination on latrine surfaces in community and household latrines, with the exception of latrine slabs/seats that were more contaminated in the community latrines under dirty conditions. The study also identified surfaces with higher levels of contamination. Findings demonstrated that well-maintained community latrines may be as clean, or cleaner, than household latrines and support the use of community latrines for improving access to sanitation infrastructure in a low-income country setting.
    • Case Report: Watching and Waiting? A Case of Incomplete Glenosphere Seating With Spontaneous Reversal in Reverse Shoulder Arthroplasty

      MacAskill, Micah L.; Thomas, Rachel; Barnes, Leslie A.; 0000-0001-9274-1751 (2020-08-27)
      Introduction: Reverse shoulder arthroplasty is a useful procedure with broadening applications, but it has the best outcomes when used for rotator cuff tear arthropathy. However, this procedure is not without complications. While scapular notching and aseptic loosening are more common complications that have been extensively studied in the literature, dissociation of the glenoid component and incomplete glenosphere seating has not received much attention. Specifically, little research has explored appropriate management of incomplete seating of the glenosphere component, and no gold standard for treatment of this complication has emerged. Methods: In the case described here, an elderly patient with an incompletely seated glenosphere component post-operatively opted to pursue conservative management in order to avoid revision surgery if possible. Results: The partially engaged, superiorly directed components in this case exhibited spontaneous complete and symmetric seating of the glenosphere between six and twelve months post-operatively, indicating that conservative management of this complication in low-demand patients may be a viable option to avoid the risks associated with revision surgery. Conclusion: Further research should be pursued to explore what patient and prosthesis design factors may be suited to observation with serial radiographs when incomplete seating of the glenosphere component occurs.
    • Case series: Failure of imaging & biochemical markers to capture disease progression in COVID-19

      Dorey-Stein, Zachariah L.; Myers, Catherine; Kumaran, Maruti; Mamary, Albert; Criner, Gerard J.; 0000-0002-3761-153X; 0000-0002-0909-5048 (2020-09-19)
      We report four individuals admitted for acute respiratory failure due to COVID-19 who demonstrated significant clinical improvement prior to discharge and subsequently were readmitted with worsening respiratory failure, elevated inflammatory markers and worsening chest imaging. We propose a multi-disciplinary discharge criterion to establish a safer discharge process including trending inflammatory markers, daily imaging and pursuing follow up CT chest, particularly in individuals with significant morbidities and health disparities.
    • Chromatin dynamics during the differentiation of long-term hematopoietic stem cells to multipotent progenitors

      Yu, Xiang Yu; Wu, Chao; Bhavanasi, Dheeraj; Wang, Hong; Gregory, Brian D.; huang, Jian; 0000-0002-1649-0038 (2017-05-30)
    • Cost-Effective Cosmetic-Grade Hyaluronan Hydrogels for ReNcell VM Human Neural Stem Cell Culture

      Ma, Weili; Suh, Won H.; 0000-0002-4036-8307 (2019-09-20)
      Hyaluronic acid (HA) is a polysaccharide polymer frequently used as a starting material to fabricate hydrogels, especially for recapitulating the brain’s extracellular matrix (ECM) for in vitro neural stem cell (NSC) cultures. Here, we report the successful synthesis of a methacrylated HA (MeHA) polymer from an inexpensive cosmetic-grade hyaluronan starting material. The MeHA polymers synthesized from cosmetic-grade HA yielded similar chemical purity to those from pharmaceutical/research-grade HA reported in the literature. Crosslinked MeHA (x-MeHA) hydrogels were formed using radical polymerization which resulted in mechanical properties matching previously reported mechanical property ranges for enhanced neuronal differentiation of NSCs. We assessed cellular adhesion, spreading, proliferation, and stiffness-dependent neuronal differentiation properties of ReNcell VM human neural stem cells (hNSCs) and compared our results to studies reported in the literature (that utilized non-human and human pluripotent cell-derived NSCs).
    • Cyberbullying, Mental Health, and Violence in Adolescents and Associations With Sex and Race: Data From the 2015 Youth Risk Behavior Survey

      Alhajji, Mohammed; Bass, Sarah; Dai, Ting; 0000-0001-6199-449X; 0000-0003-2742-1609 (2019-08-06)
      Background. Cyberbullying is a serious issue among adolescents, but little is known about how demographics are associated with mental health conditions and violent behaviors. The present study examined the association of cyberbullying victimization with mental health conditions and violent behaviors among adolescents, specifically examining potential differences by sex and race. Methods. National data obtained from a representative sample of 9th to 12th grade students (N = 15 465) in the United States were examined using bivariate and logistic regression analysis. Results. More than 15% of students reported cyberbullying victimization. Females were twice as likely to report victimization than males, and non-white students were 50% less likely to report cyberbullying victimization. Cyberbullying victimization was significantly more likely in students who reported depressive symptoms, suicidal ideation, suicide planning, carrying a weapon, and engaging in a physical fight. These associations were more pronounced in males. Conclusions. Our findings show that female and white adolescents are at increased risk of being cyberbullied. However, negative mental health outcomes and violent behaviors are more pronounced in males, indicating potential negative effects of being a cyberbullying victim based on sex. We envisage the best way to combat cyberbullying is to develop programs that are sensitive to potential demographic differences to empower students based on individual risks.
    • Effect of Education and Cardboard Bassinet Distribution on Newborn Bed-Sharing

      Heere, Megan; Moughan, Beth; Alfonsi, Joseph; Rodriguez, Jennifer; Aronoff, Stephen C.; 0000-0001-7674-7475 (2019-02-25)
      Objective. This study sought to determine if infant sleep education plus a cardboard bassinet reduced bed-sharing, a risk factor for sudden infant death syndrome (SIDS) and sleep-related deaths (SRD), in the first week of life. Methods. Women delivered between 1/1/2015-11/15/2016 were interviewed by phone within 72 hours of discharge. Control 1 delivered through 10/31/2015 (previously reported); Control 2: 11/1/2015-2/7/2016; Intervention 1 received inpatient safe sleep education and delivered between 2/8/2016-5/4/2016; Intervention 2 also received a cardboard bassinet and delivered after 5/4/2016. Subjects self-reported bed-sharing, newborn sleep position, feeding method, and sleep environment; demographic data was obtained from medical records. Bayesian methodology compared bed-sharing rates between aggregated control and intervention groups; results were expressed as posterior rates, rate ratios, and 95% credible intervals (CredInt); the posterior probability that the rate ratio was > 1(Bayesian probability) was determined by calculation and simulation. Results. 5187 eligible subjects, 2763 (53%) completed the survey (Control 1: n=1264; Control 2: n=423; Intervention 1: n=391; Intervention 2: n=685). Bed-sharing rates: Control: 6.3% (5.2,7.4); Intervention: 4.7% (3.5,5.9). Rate ratio (Control/Intervention) was 1.36 (0.95,1.83) and the Bayesian probability that the rate ratio >1 was .96 and .97 by calculation and simulation, respectively. Bed-sharing rates for exclusively breastfed infants: Control: 11% (7.4, 14.6); Intervention: 5.9% (2.7, 9.2); Rate ratio was 2.00 (1.01, 3.15) and the Bayesian probability that the rate ratio >1 was .993. Conclusions. Infant sleep education plus a cardboard bassinet reduced the rate of bed-sharing in the first week of life, particularly among exclusively breastfeeding dyads.
    • Effects of Revegetation on Soil Physical and Chemical Properties in Solar Photovoltaic Infrastructure

      Choi, Chong Seok; Cagle, Alexander E.; Macknick, Jordan; Bloom, Dellena E.; Caplan, Joshua; Ravi, Sujith; 0000-0002-6860-2038; 0000-0003-4624-2956; 0000-0002-0425-9373 (2020-08-11)
      Solar photovoltaic (PV) technology is being deployed at an unprecedented rate. However, utility-scale solar energy development is land intensive and its large-scale installation can have negative impacts on the environment. In particular, solar energy infrastructure can require extensive landscape modification that transforms soil ecological functions, thereby impacting hydrologic, vegetative, and carbon dynamics. However, reintroducing native vegetation to solar PV sites may be a means of restoring their soils. To this end, we investigated critical soil physical and chemical parameters at a revegetated photovoltaic array and an adjacent reference grassland in Colorado, United States. Seven years after revegetation, we found that carbon and nitrogen remained lower in the PV soil than in the reference soil and contained a greater fraction of coarse particles. We also found that the PV modules introduced heterogeneity in the soil moisture distribution, with precipitation accumulating along the lower edges of panels. The redistribution of soil moisture by panel arrays could potentially be used in concert with planting strategies to maximize plant growth or minimize soil erosion, and should be considered when evaluating the potential to co-locate vegetation with solar infrastructure.
    • Essential or Expendable Supports? Assessing the Relationship between School Climate and Student Outcomes

      Sørensen, Jesper; Morgan, Stephen (2017-01-10)
      Sociologists of education argue that school organizational practices and climates influence students’ academic outcomes. The predominant measure of school climates are aggregated student and teacher survey reports, which are diffusing into official educational statistics. Unfortunately, most studies are unable to rigorously assess the causal effects of these measures of school organization. This study does so by examining the effects of school climate experienced in grades 4–8 by different cohorts of students in Chicago Public Schools (CPS). Improvement in school climates has small positive associations with students’ eighth grade test scores and null to minimal associations with students’ chances of on-time ninth grade promotion and high school graduation.
    • Exercise capacity is associated with hospital readmission among patients with diabetes

      Zisman-Ilani, Yaara; Fasing, Kevin; Weiner, Mark; Rubin, Daniel; Zisman-Ilani|0000-0001-6852-2583; Rubin|0000-0002-6871-6246 (2020-10-05)
      Introduction: Patients with diabetes are at greater risk of hospital readmission than patients without diabetes. There is a need to identify more modifiable risk factors for readmission as potential targets for intervention. Cardiorespiratory fitness is a predictor of morbidity and mortality. The purpose of this study was to examine whether there is an association between exercise capacity based on the maximal workload achieved during treadmill stress testing and readmission among patients with diabetes. Research design and methods: This retrospective cohort study included adult patients with diabetes discharged from an academic medical center between July 1, 2012 and December 31, 2018 who had a stress test documented before the index discharge. Univariate analysis and multinomial multivariable logistic regressions were used to evaluate associations with readmission within 30 days, 6 months, and 1 year of discharge. Exercise capacity was measured as metabolic equivalents (METs). Results: A total of 580 patients with 1598 hospitalizations were analyzed. Mean METs of readmitted patients were significantly lower than for non-readmitted patients (5.7 (2.6) vs 6.7 (2.6), p<0.001). After adjustment for confounders, a low METs level (<5) was associated with higher odds of readmission within 30 days (OR 5.46 (2.22–13.45), p<0.001), 6 months (OR 2.78 (1.36–5.65), p=0.005), and 1 year (OR 2.16 (1.12–4.16), p=0.022) compared with medium (5–7) and high (>7) METs level. During the 6.5-year study period, patients with low METs had a mean of 3.2±3.6 hospitalizations, while those with high METs had 2.5±2.4 hospitalizations (p=0.007). Conclusions: Lower exercise capacity is associated with a higher risk of readmission within 30 days, 6 months, and 1 year, as well as a greater incidence of hospitalization, in patients with diabetes. Future studies are needed to explore whether exercise reduces readmission risk in this population.
    • First records of the mourning gecko (Lepidodactylus lugubris Duméril and Bibron, 1836), common house gecko (Hemidactylus frenatus in Duméril, 1836), and Tokay gecko (Gekko gecko Linnaeus, 1758) on Curaçao, Dutch Antilles, and remarks on their Caribbean distributions

      Katsanevakis, Stelios; Integrative Ecology Lab, Center for Biodiversity (2018-10-16)
      Globally, geckos (Gekkonidae) are one of the most successful reptile families for exotic species. With the exception of the widespread invader, Hemidactylus mabouia, however, introductions of exotic gecko species are a more recent occurrence in the Caribbean islands despite extensive introductions of exotic geckos in the surrounding Caribbean region. Here we report three new exotic gecko species establishments on the mid-sized Caribbean island of Curaçao (Leeward Antilles). Of the three new exotic species, the mourning gecko, Lepidodactylus lugubris (Duméril and Bibron, 1836) has the largest distribution on Curaçao and has likely been established for the longest time. The common house gecko, Hemidactylus frenatus (in Duméril, 1836) has a limited distribution and was likely a more recent introduction. Finally, the Tokay gecko, Gekko gecko (Linnaeus, 1758), escaped from captivity and is known from a single locality. Both L. lugubris and H. frenatus have had widespread distributions in the greater Caribbean region for over 70 years yet have only been reported from Caribbean islands within the past decade. Comparatively, the scope of G. gecko introductions on Caribbean islands is similar to L. lugubris and H. frenatus but introduced populations of G. gecko in the greater Caribbean region are virtually absent. These patterns indicate that different introduction pathways (intentional vs passive) may affect the size of exotic geographic ranges, and that the rate of exotic gecko introductions to Caribbean islands may now be increasing.
    • From leads to leadless: A convoluted journey

      Dulam, Vipin; Cooper, Joshua M.; Gangireddy, Chethan; Kashem, Mohammed A.; Toyoda, Yoshiya; Keshavamurthy, Suresh; 0000-0002-5578-1911 (2020-07-21)
    • Hyperammonemia Post Lung Transplantation: A Review

      Leger, Robert; Silverman, Matthew S.; Hauck, Ellen S.; Guvakova, Ksenia D.; Leger|0000-0002-2013-4685 (2020-10-26)
      Hyperammonemia is the pathological accumulation of ammonia in the blood, which can occur in many different clinical settings. Most commonly in adults, hyperammonemia occurs secondary to hepatic dysfunction; however, it is also known to be associated with other pathologies, surgeries, and medications. Although less common, hyperammonemia has been described as a rare, but consistent complication of solid organ transplantation. Lung transplantation is increasingly recognized as a unique risk factor for the development of this condition, which can pose grave health risks—including long-term neurological sequelae and even death. Recent clinical findings have suggested that patients receiving lung transplantations may experience postoperative hyperammonemia at rates as high as 4.1%. A wide array of etiologies has been attributed to this condition. A growing number of case studies and investigations suggest disseminated opportunistic infection with Ureaplasma or Mycoplasma species may drive this metabolic disturbance in lung transplant recipients. Regardless of the etiology, hyperammonemia presents a severe clinical problem with reported mortality rates as high as 75%. Typical treatment regimens are multimodal and focus on 3 main avenues of management: (1) the reduction of impact on the brain through the use of neuroprotective medications and decreasing cerebral edema, (2) augmentation of mechanisms for the elimination of ammonia from the blood via hemodialysis, and (3) the diminishment of processes producing predominantly using antibiotics. The aim of this review is to detail the pathophysiology of hyperammonemia in the setting of orthotopic lung transplantation and discuss methods of identifying and managing patients with this condition.
    • Identifying profiles of brain structure and associations with current and future psychopathology in youth

      Mattoni, Matthew; Wilson, Sylia; Olino, Thomas M. (2021-09-14)
      Brain structure is often studied as a marker of youth psychopathology by examining associations between volume or thickness of individual regions and specific diagnoses. However, these univariate approaches do not address whether the effect of a particular region may depend on the structure of other regions. Here, we identified subgroups of individuals with distinct profiles of brain structure and examined how these profiles were associated with concurrent and future youth psychopathology. We used latent profile analysis to identify distinct neuroanatomical profiles of subcortical region volume and orbitofrontal cortical thickness in the ABCD study (N = 9376, mean age = 9.91, SD = 0.62). We identified a five-profile solution consisting of a reduced subcortical volume profile, a reduced orbitofrontal thickness profile, a reduced limbic and elevated striatal volume profile, an elevated orbitofrontal thickness and reduced striatal volume profile, and an elevated orbitofrontal thickness and subcortical volume profile. While controlling for age, sex, and intracranial volume, profiles exhibited differences in concurrent psychopathology measured dimensionally and categorically and in psychopathology at 1-year follow-up measured dimensionally. Results show that profiles of brain structure have incremental validity for associations with youth psychopathology beyond intracranial volume.
    • Improving Interlayer Adhesion of Poly(p-phenylene terephthalamide) (PPTA)/Ultra-high-molecular-weight Polyethylene (UHMWPE) Laminates Prepared by Plasma Treatment and Hot Pressing Technique

      Temple Materials Institute (Temple University) (2021-08-05)
      Poly(p-phenylene terephthalamide) (PPTA) is a high-performance polymer that has been utilized in a range of applications. Although PPTA fibers are widely used in various composite materials, laminar structures consisting of PPTA and ultra-high-molecular-weight polyethylene (UHMWPE), are less reported. The difficulty in making such composite structures is in part due to the weakness of the interface formed between these two polymers. In this study, a layered structure was produced from PPTA fabrics and UHMWPE films via hot pressing. To improve the interlayer adhesion, oxygen plasma was used to treat the PPTA and the UHMWPE surfaces prior to lamination. It has been found that while plasma treatment on the UHMWPE surface brought about a moderate increase in interlayer adhesion (up to 14%), significant enhancement was achieved on the samples fabricated with plasma treated PPTA (up to 91%). It has been assumed that both surface roughening and the introduction of functional groups contributed to this improvement.