The Effect of Coupling Agents and Graphene on the Mechanical Properties of Film-Based Post-Consumer Recycled Plastic.

This study aims to improve the mechanical properties of post-consumer recycled (PCR) plastic composed primarily of polypropylene (PP) and polyethylene (PE), which generally exhibit poor miscibility, by applying coupling agents and graphene. Here, we compare a commercially available coupling agent with a directly synthesized maleic anhydride (MA) coupling agent. When applied to a 5:5 blend of recycled PP and PE, an optimum tensile strength was achieved at a 3 wt% coupling agent concentration, with the MA coupling agent outperforming the commercial one. Characterization through Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry analysis (TGA) revealed a PP:PE ratio of approximately 3:7 in the PCR plastics, with 4.86% heterogeneous materials present. Applying 3 wt% of the commercial and MA coupling agents to the PCR plastics resulted in a significant 53.9% increase in the tensile strength, reaching 11.25 MPa, and a remarkable 421.54% increase in the melt flow index (MFI), reaching 25.66 g/10 min. Furthermore, incorporating 5 wt% graphene led to a notable 64.84% increase in the tensile strength. In addition, the application of MA coupling agents and graphene improved the thermal stability of the PCR plastics. These findings show significant promise for addressing environmental concerns associated with plastic waste by facilitating the recycling of PCR plastics into new products. The utilization of coupling agents and graphene offers a viable approach to enhance the mechanical properties of PCR plastics, paving the way for sustainable and environmentally friendly solutions.

Tailoring Multifunctional and Lightweight Hierarchical Hybrid Graphene Nanoplatelet and Glass Fiber Composites.

In this work, hybrid polypropylene (PP)-based composites reinforced with graphene nanoplatelets (GnPs) and glass fiber (GF) were fabricated by injection molding to elucidate how the hybrid approach can produce synergistic effects capable of achieving properties and functionalities not possible in biphasic composites. Synergism between the reinforcements translated to improved mechanical performance, which was attributed to the chemically and/or electrostatically assembled hierarchical structure that facilitates load transfer at the interface while simultaneously tailoring the crystalline microstructure of the matrix by inducing transcrystallization and ß-crystal formation. It was demonstrated that there exists an optimal concentration of 0.5 wt % GnP, producing the greatest mechanical properties and synergistic effect, corresponding to the highest degree of crystallinity (∼6% greater than Neat PP) and peak formation of ß-crystals within the PP matrix. The greatest synergistic effect was found to be ∼52 and ∼39% for the specific tensile strength and flexural strength, respectively. The same optimal concentration of GnPs was found to produce the highest synergistic effect for thermal conductivity of ∼68% due to the volume exclusion effect induced by the GFs combined with the higher crystallinity of the microstructure, promoting the formation of thermally conductive pathways. Ultimately, the mechanisms contributing to the synergistic effect presented in this work can be used to maximize the performance of hybrid composite systems, giving them the potential to be tailored for a variety of high-performance industrial applications to meet the rising demands for ultra-strong, thermally conductive, and lightweight materials.

Reversal of viral and epigenetic HLA class I repression in Merkel cell carcinoma.

Cancers avoid immune surveillance through an array of mechanisms, including perturbation of HLA class I antigen presentation. Merkel cell carcinoma (MCC) is an aggressive, HLA-I-low, neuroendocrine carcinoma of the skin often caused by the Merkel cell polyomavirus (MCPyV). Through the characterization of 11 newly generated MCC patient-derived cell lines, we identified transcriptional suppression of several class I antigen presentation genes. To systematically identify regulators of HLA-I loss in MCC, we performed parallel, genome-scale, gain- and loss-of-function screens in a patient-derived MCPyV-positive cell line and identified MYCL and the non-canonical Polycomb repressive complex 1.1 (PRC1.1) as HLA-I repressors. We observed physical interaction of MYCL with the MCPyV small T viral antigen, supporting a mechanism of virally mediated HLA-I suppression. We further identify the PRC1.1 component USP7 as a pharmacologic target to restore HLA-I expression in MCC.

Improved Cell Morphology and Surface Roughness in High-Temperature Foam Injection Molding Using a Long-Chain Branched Polypropylene.

Long-chain branched polypropylene (LCB PP) has been used extensively to improve cell morphologies in foaming applications. However, most research focuses on low melt flow rate (MFR) resins, whereas foam production methods such as mold-opening foam injection molding (MO-FIM) require high-MFR resins to improve processability. A systematic study was conducted comparing a conventional linear PP, a broad molecular weight distribution (BMWD) linear PP, and a newly developed BMWD LCB PP for use in MO-FIM. The effects of foaming temperature and molecular architecture on cell morphology, surface roughness, and mechanical properties were studied by utilizing two chemical blowing agents (CBAs) with different activation temperatures and varying packing times. At the highest foaming temperatures, BMWD LCB PP foams exhibited 887% higher cell density, 46% smaller cell sizes, and more uniform cell structures than BWMD linear PP. Linear PP was found to have a surface roughness 23% higher on average than other resins. The BMWD LCB PP was found to have increased flexural modulus (44%) at the cost of decreased toughness (-88%) compared to linear PP. The branched architecture and high molecular weight of the BMWD LCB PP contributed to improved foam morphologies and surface quality in high-temperature MO-FIM conditions.

Targeting the Fibroblast Growth Factor Receptor (FGFR) in Advanced Cholangiocarcinoma: Clinical Trial Progress and Future Considerations.

Landmark molecular profiling efforts have identified multiple targetable alterations in cholangiocarcinoma. Among the molecular-driven subsets of cholangiocarcinoma, targeting the fibroblast growth factor receptor (FGFR) has shown promise and represents the first targeted therapy to be approved in treatment-refractory, advanced cholangiocarcinoma. In this review, we provide an up-to-date overview of the clinical development of FGFR inhibitors in advanced cholangiocarcinoma. We review the FGFR pathway and discuss emerging issues including resistance to FGFR inhibitors. We end with a discussion on future considerations to optimize the potential of this class of therapeutics in advanced cholangiocarcinoma.

Personal neoantigen vaccines induce persistent memory T cell responses and epitope spreading in patients with melanoma.

Personal neoantigen vaccines have been envisioned as an effective approach to induce, amplify and diversify antitumor T cell responses. To define the long-term effects of such a vaccine, we evaluated the clinical outcome and circulating immune responses of eight patients with surgically resected stage IIIB/C or IVM1a/b melanoma, at a median of almost 4 years after treatment with NeoVax, a long-peptide vaccine targeting up to 20 personal neoantigens per patient ( NCT01970358 ). All patients were alive and six were without evidence of active disease. We observed long-term persistence of neoantigen-specific T cell responses following vaccination, with ex vivo detection of neoantigen-specific T cells exhibiting a memory phenotype. We also found diversification of neoantigen-specific T cell clones over time, with emergence of multiple T cell receptor clonotypes exhibiting distinct functional avidities. Furthermore, we detected evidence of tumor infiltration by neoantigen-specific T cell clones after vaccination and epitope spreading, suggesting on-target vaccine-induced tumor cell killing. Personal neoantigen peptide vaccines thus induce T cell responses that persist over years and broaden the spectrum of tumor-specific cytotoxicity in patients with melanoma.

Two-Dimensional Correlation Analysis of iPP Bead Foaming Thermal Features Modeled by Fast Scanning Calorimetry.

The bead foaming of semicrystalline polymers is a complex thermal process involving the formation of multiple crystalline populations, which serve the dual purposes of ensuring the structural integrity of beads while also allowing bead sintering at the interface. The quality of this "double melting peak" structure is determined by the temperature and duration of the isothermal treatment of the beads as well as the quenching rate following the isotherm. Currently, the intricacies of the quenching process are not very well-known due to the challenge of replicating these rapid cooling rates in a laboratory setting. Fast-scanning calorimetry was used to reproduce these conditions for isotactic polypropylene (iPP), revealing optimal quenching rates for the bead foaming of iPP. We further probed these thermal features using two-dimensional correlation analysis as a tool to understand the dynamics, interdependence, and relative contributions of multiple thermal events such as glass transition, mesophase formation, cold crystallization, and melting in response to the perturbation of the quenching rate.

Tuning High and Low Temperature Foaming Behavior of Linear and Long-Chain Branched Polypropylene via Partial and Complete Melting.

While existing foam studies have identified processing parameters, such as high-pressure drop rate, and engineering measures, such as high melt strength, as key factors for improving foamability, there is a conspicuous absence of studies that directly relate foamability to material properties obtained from fundamental characterization. To bridge this gap, this work presents batch foaming studies on one linear and two long-chain branched polypropylene (PP) resins to investigate how foamability is affected by partial melting (Method 1) and complete melting followed by undercooling (Method 2). At temperatures above the melting point, similar expansion was obtained using both foaming procedures within each resin, while the PP with the highest strain hardening ratio (13) exhibited the highest expansion ratio (45 ± 3). At low temperatures, the foamability of all resins was dramatically improved using Method 2 compared to Method 1, due to access to lower foaming temperatures (<150 °C) near the crystallization onset. Furthermore, Method 2 resulted in a more uniform cellular structure over a wider temperature range (120-170 °C compared to 155-175 °C). Overall, strong extensional hardening and low onset of crystallization were shown to give rise to foamability at high and low temperatures, respectively, suggesting that both characteristics can be appropriately used to tune the foamability of PP in industrial foaming applications.

Tunable Tensile Properties of Polypropylene and Polyethylene Terephthalate Fibrillar Blends through Micro-/Nanolayered Extrusion Technology.

Fiber-reinforcement is a well-established technique to enhance the tensile properties of polymer composites, which is achieved via changing the reinforcing material concentration and orientation. However, the conventional method can be costly and may lead to poor compatibility issues. To overcome these challenges, we demonstrate the use of micro-/nanolayer (MNL) extrusion technology to tune the mechanical properties of polypropylene (PP)/polyethylene terephthalate (PET) fibrillar blends. PET nanofibers-in-PP microfiber composites, with 3, 7, and 15 wt.% PET, are first prepared using a spunbond system to induce high aspect-ratio PET nanofibers. The PP/PET fibers are then reprocessed in an MNL extrusion system and subjected to shear and extensional flow fields in the channels of the uniquely designed layer multipliers. Increasing the mass flow rate and number of multipliers is shown to orient the PET nanofibers along the machine direction (MD), as confirmed via scanning electron microscopy. Tensile tests reveal that up to a 45% and 46% enhancement in elastic modulus and yield strength are achieved owing to the highly aligned PET nanofibers along the MD under strongest processing conditions. Overall, the range of tensile properties obtained using MNL extrusion implies that the properties of fiber-reinforced composites can be further tuned by employing this processing technique.

Cancer-Germline Antigen Expression Discriminates Clinical Outcome to CTLA-4 Blockade.

CTLA-4 immune checkpoint blockade is clinically effective in a subset of patients with metastatic melanoma. We identify a subcluster of MAGE-A cancer-germline antigens, located within a narrow 75 kb region of chromosome Xq28, that predicts resistance uniquely to blockade of CTLA-4, but not PD-1. We validate this gene expression signature in an independent anti-CTLA-4-treated cohort and show its specificity to the CTLA-4 pathway with two independent anti-PD-1-treated cohorts. Autophagy, a process critical for optimal anti-cancer immunity, has previously been shown to be suppressed by the MAGE-TRIM28 ubiquitin ligase in vitro. We now show that the expression of the key autophagosome component LC3B and other activators of autophagy are negatively associated with MAGE-A protein levels in human melanomas, including samples from patients with resistance to CTLA-4 blockade. Our findings implicate autophagy suppression in resistance to CTLA-4 blockade in melanoma, suggesting exploitation of autophagy induction for potential therapeutic synergy with CTLA-4 inhibitors.

Restoring Ureagenesis in Hepatocytes by CRISPR/Cas9-mediated Genomic Addition to Arginase-deficient Induced Pluripotent Stem Cells.

Urea cycle disorders are incurable enzymopathies that affect nitrogen metabolism and typically lead to hyperammonemia. Arginase deficiency results from a mutation in Arg1, the enzyme regulating the final step of ureagenesis and typically results in developmental disabilities, seizures, spastic diplegia, and sometimes death. Current medical treatments for urea cycle disorders are only marginally effective, and for proximal disorders, liver transplantation is effective but limited by graft availability. Advances in human induced pluripotent stem cell research has allowed for the genetic modification of stem cells for potential cellular replacement therapies. In this study, we demonstrate a universally-applicable CRISPR/Cas9-based strategy utilizing exon 1 of the hypoxanthine-guanine phosphoribosyltransferase locus to genetically modify and restore arginase activity, and thus ureagenesis, in genetically distinct patient-specific human induced pluripotent stem cells and hepatocyte-like derivatives. Successful strategies restoring gene function in patient-specific human induced pluripotent stem cells may advance applications of genetically modified cell therapy to treat urea cycle and other inborn errors of metabolism.

Rapid and efficient conversion of integration-free human induced pluripotent stem cells to GMP-grade culture conditions.

Data suggest that clinical applications of human induced pluripotent stem cells (hiPSCs) will be realized. Nonetheless, clinical applications will require hiPSCs that are free of exogenous DNA and that can be manufactured through Good Manufacturing Practice (GMP). Optimally, derivation of hiPSCs should be rapid and efficient in order to minimize manipulations, reduce potential for accumulation of mutations and minimize financial costs. Previous studies reported the use of modified synthetic mRNAs to reprogram fibroblasts to a pluripotent state. Here, we provide an optimized, fully chemically defined and feeder-free protocol for the derivation of hiPSCs using synthetic mRNAs. The protocol results in derivation of fully reprogrammed hiPSC lines from adult dermal fibroblasts in less than two weeks. The hiPSC lines were successfully tested for their identity, purity, stability and safety at a GMP facility and cryopreserved. To our knowledge, as a proof of principle, these are the first integration-free iPSCs lines that were reproducibly generated through synthetic mRNA reprogramming that could be putatively used for clinical purposes.

Generation and characterization of transgene-free human induced pluripotent stem cells and conversion to putative clinical-grade status.

INTRODUCTION: The reprogramming of a patient's somatic cells back into induced pluripotent stem cells (iPSCs) holds significant promise for future autologous cellular therapeutics. The continued presence of potentially oncogenic transgenic elements following reprogramming, however, represents a safety concern that should be addressed prior to clinical applications. The polycistronic stem cell cassette (STEMCCA), an excisable lentiviral reprogramming vector, provides, in our hands, the most consistent reprogramming approach that addresses this safety concern. Nevertheless, most viral integrations occur in genes, and exactly how the integration, epigenetic reprogramming, and excision of the STEMCCA reprogramming vector influences those genes and whether these cells still have clinical potential are not yet known. METHODS: In this study, we used both microarray and sensitive real-time PCR to investigate gene expression changes following both intron-based reprogramming and excision of the STEMCCA cassette during the generation of human iPSCs from adult human dermal fibroblasts. Integration site analysis was conducted using nonrestrictive linear amplification PCR. Transgene-free iPSCs were fully characterized via immunocytochemistry, karyotyping and teratoma formation, and current protocols were implemented for guided differentiation. We also utilized current good manufacturing practice guidelines and manufacturing facilities for conversion of our iPSCs into putative clinical grade conditions. RESULTS: We found that a STEMCCA-derived iPSC line that contains a single integration, found to be located in an intronic location in an actively transcribed gene, PRPF39, displays significantly increased expression when compared with post-excised stem cells. STEMCCA excision via Cre recombinase returned basal expression levels of PRPF39. These cells were also shown to have proper splicing patterns and PRPF39 gene sequences. We also fully characterized the post-excision iPSCs, differentiated them into multiple clinically relevant cell types (including oligodendrocytes, hepatocytes, and cardiomyocytes), and converted them to putative clinical-grade conditions using the same approach previously approved by the US Food and Drug Administration for the conversion of human embryonic stem cells from research-grade to clinical-grade status. CONCLUSION: For the first time, these studies provide a proof-of-principle for the generation of fully characterized transgene-free human iPSCs and, in light of the limited availability of current good manufacturing practice cellular manufacturing facilities, highlight an attractive potential mechanism for converting research-grade cell lines into putatively clinical-grade biologics for personalized cellular therapeutics.

Boot cAMP: educational outcomes after 4 successive years of preparatory simulation-based training at onset of internship.

PURPOSE: Preparatory training for new trainees beginning residency has been used by a variety of programs across the country. To improve the clinical orientation process for our new postgraduate year (PGY)-1 residents, we developed an intensive preparatory training curriculum inclusive of cognitive and procedural skills, training activities considered essential for early PGY-1 clinical management. We define our surgical PGY-1 Boot Camp as preparatory simulation-based training implemented at the onset of internship for introduction of skills necessary for basic surgical patient problem assessment and management. This orientation process includes exposure to simulated patient care encounters and technical skills training essential to new resident education. We report educational results of 4 successive years of Boot Camp training. Results were analyzed to determine if performance evidenced at onset of training was predictive of later educational outcomes. METHODS: Learners were PGY-1 residents, in both categorical and preliminary positions, at our medium-sized surgical residency program. Over a 4-year period, from July 2007 to July 2010, all 30 PGY-1 residents starting surgical residency at our institution underwent specific preparatory didactic and skills training over a 9-week period. This consisted of mandatory weekly 1-hour and 3-hour sessions in the Simulation Center, representing a 4-fold increase in time in simulation laboratory training compared with the remainder of the year. Training occurred in 8 procedural skills areas (instrument use, knot-tying, suturing, laparoscopic skills, airway management, cardiopulmonary resuscitation, central venous catheter, and chest tube insertion) and in simulated patient care (shock, surgical emergencies, and respiratory, cardiac, and trauma management) using a variety of high- and low-tech simulation platforms. Faculty and senior residents served as instructors. All educational activities were structured to include preparatory materials, pretraining briefing sessions, and immediate in-training or post-training review and debriefing. Baseline cognitive skills were assessed with written tests on basic patient management. Post-Boot Camp tests similarly evaluated cognitive skills. Technical skills were assessed using a variety of task-specific instruments, and expressed as a mean score for all activities for each resident. All measurements were expressed as percent (%) best possible score. Cognitive and technical performance in Boot Camp was compared with subsequent clinical and core curriculum evaluations including weekly quiz scores, annual American Board of Surgery In-Training Examination (ABSITE) scores, program in-training evaluations (New Innovations, Uniontown, Ohio), and operative assessment instrument scores (OP-Rate, Baystate Medical Center, Springfield, Massachusetts) for the remainder of the PGY-1 year. RESULTS: Performance data were available for 30 PGY-1 residents over 4 years. Baseline cognitive skills were lower for the first year of Boot Camp as compared with subsequent years (71 ± 13, 83 ± 9, 84 ± 11, and 86 ± 6, respectively; p = 0.028, analysis of variance; ANOVA). Performance improved between pretests and final testing (81 ± 11 vs 89 ± 7; p < 0.001 paired t test). There was statistically significant correlation between Boot Camp final cognitive test results and American Board of Surgery In-Training Examination scores (p = 0.01; n = 22), but not quite significant for weekly curriculum quiz scores (p = 0.055; n = 22) and New Innovations cognitive assessments (p = 0.09; n = 25). Statistically significant correlation was also noted between Boot Camp mean overall skills and New Innovations technical skills assessments (p = 0.002; n = 25) and OP-Rate assessments (p = 0.01; n = 12). CONCLUSIONS: Individual simulation-based Boot Camp performance scores for cognitive and procedural skills assessments in PGY-1 residents correlate with subjective and objective clinical performance evaluations. This concurrent correlation with multiple traditional evaluation methods used to express competency in our residency program supports the use of Boot Camp performance measures as needs assessment tools as well as adjuncts to cumulative resident evaluation data.

Implementation of full patient simulation training in surgical residency.

PURPOSE: Simulated patient care has gained acceptance as a medical education tool but is underused in surgical training. To improve resident clinical management in critical situations relevant to the surgical patient, high-fidelity full patient simulation training was instituted at Baystate Medical Center in 2005 and developed during successive years. We define surgical patient simulation as clinical management performed in a high fidelity environment using a manikin simulator. This technique is intended to be specifically modeled experiential learning related to the knowledge, skills, and behaviors that are fundamental to patient care. We report 3 academic years' use of a patient simulation curriculum. METHODS: Learners were PGY 1-3 residents; 26 simulated patient care experiences were developed based on (1) designation as a critical management problem that would otherwise be difficult to practice, (2) ability to represent the specific problem in simulation, (3) relevance to the American Board of Surgery (ABS) certifying examination, and/or (4) relevance to institutional quality or morbidity and mortality reports. Although training started in 2005, data are drawn from the period of systematic and mandatory training spanning from July 2006 to June 2009. Training occurred during 1-hour sessions using a computer-driven manikin simulator (METI, Sarasota, Florida). Educational content was provided either before or during presimulation briefing sessions. Scenario areas included shock states, trauma and critical care case management, preoperative processes, and postoperative conditions and complications. All sessions were followed by facilitated debriefing. Likert scale-based multi-item assessments of core competency in medical knowledge, patient care, diagnosis, management, communication, and professionalism were used to generate a performance score for each resident for each simulation (percentage of best possible score). Performance was compared across PGYs by repeated-measures analysis of variance and Wilcoxon rank sum tests. RESULTS: Residents participated in 4.5 ± 1.4 sessions per academic year. Compliance with scheduled training was 88%, 90%, and 99% over successive years. Performance data were available for 39 PGY1, 2, and 3 residents. Ten individual residents could be followed between PGY1 and PGY2. For these individuals, improvement in mean performance was detected for the PGY2 (81% ± 5% vs 86% ± 4%; p < 0.01). Performance improvement was also detected for 4 individual residents who could be followed during all 3 years (82% ± 4%, 86% ± 2%, and 91% ± 1%, respectively, p < 0.005). Internal consistency for multi-item assessments was high (Cronbach's alpha = 0.80). Of note, 8 of 39 residents had performance scores >2 standard deviations below mean for the PGY level and 5 of these had deficiencies in clinical performance noted by other evaluation methods. CONCLUSIONS: Patient simulation training was implemented successfully with good compliance in this medium-sized surgical residency training program, but clear challenges were encountered with issues related to the number and range of experiences available per resident, competition with other educational activities, and fidelity and realism. Initial experience suggests that the associated assessment methods can detect predictable improvements in patient management skills across successive residency years, as well as potentially deficient management. Additional work is required to determine the educational effect of this training on resident clinical competency.