Investigation of team dynamics and group performance in the product engineering process

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaf 19).The cultural traits of a project engineering team can strongly influence the performance of its members and the quality of the product. The 2.009 Product Engineering Processes class provides an opportunity for investigating the relationships between group dynamics and performance as the student groups work with customers and advisors on brainstorming, designing, testing and construction a fully-functional mechanical prototype over the course of a semester. Performance was measured as a function of time using information from the class ranking system while each team's cultural traits were measured using two surveys that all students were required to complete. Results of this study revealed that the most influential traits on group performance were task understanding, organization and creativity. Analysis of the survey data showed that feedback and professional communication increased while flexibility decreased as the student groups matured from their initial formative stages into fully defined teams. A comparison of teams with sections that reported polar opposite team dynamics revealed that sections with negative group dynamics performed worse than their positive counterparts, though this trend did not hold in the context of the entire class.(cont.) Investigation of the dynamic profiles of these teams revealed that organization, task understanding, creativity and efficient use of resources had the greatest influence on performance. The results of a direct comparison of high and low performing teams for each assignment confirmed this trend.by Stephanie K. Lee.S.B

The genetics of colored sequence synesthesia: Evidence of linkage to chromosome 16q and genetic heterogeneity for the condition

Synesthesia is a perceptual condition in which normal sensory stimulation can trigger anomalous sensory experiences. For example, synesthetes may experience colors in response to sounds, tastes in response to words, or smells in response to touch. We here focus on colored sequence synesthesia, in which color experiences are triggered by learned ordinal sequences such as letters, numbers, weekdays and months. Although synesthesia has been noted in the scientific literature for over a century, it is understood only at the level of the phenomenology, and not at the molecular and neural levels. We have performed a linkage analysis to identify the first genetic loci responsible for the increased neural crosstalk underlying colored sequence synesthesia. Our analysis has identified a 23 MB region on chromosome 16 as a putative locus for the trait. Our data provide the first step in understanding neural crosstalk from its molecular basis to its behavioral consequences, opening a new inroad into the understanding of the multisensory brain

A combined biomarker and clinical panel for chronic graft versus host disease diagnosis.

Whilst many chronic graft versus host disease (cGVHD) biomarkers have been previously reported, few have been verified in an independent cGVHD cohort. We aimed to verify the diagnostic accuracy of previously reported markers of cGVHD in a multi-centre Chronic GVHD Consortium. A total of 42 RNA and 18 protein candidate biomarkers were assessed amongst 59 cGVHD cases and 33 matched non-GVHD controls. Total RNA was isolated from PBMC, and RNA markers were quantified using PCR. Serum protein markers were quantified using ELISA. A combined 3 RNA biomarker (IRS2, PLEKHF1 and IL1R2) and 2 clinical variables (recipient CMV serostatus and conditioning regimen intensity) panel accurately (AUC 0.81) segregated cGVHD cases from controls. Other studied RNA and protein markers were not confirmed as accurate cGVHD diagnostic biomarkers. The studied markers failed to segregate higher risk cGVHD (per overall NIH 0-3 score, and overlap versus classic cGVHD status). These data support the need for multiple independent verification studies for the ultimate clinical application of cGVHD diagnostic biomarkers

Characteristics and treatments of large cystic brain metastasis: radiosurgery and stereotactic aspiration.

Brain metastasis represents one of the most common causes of intracranial tumors in adults, and the incidence of brain metastasis continues to rise due to the increasing survival of cancer patients. Yet, the development of cystic brain metastasis remains a relatively rare occurrence. In this review, we describe the characteristics of cystic brain metastasis and evaluate the combined use of stereotactic aspiration and radiosurgery in treating large cystic brain metastasis. The results of several studies show that stereotactic radiosurgery produces comparable local tumor control and survival rates as other surgery protocols. When the size of the tumor interferes with radiosurgery, stereotactic aspiration of the metastasis should be considered to reduce the target volume as well as decreasing the chance of radiation induced necrosis and providing symptomatic relief from mass effect. The combined use of stereotactic aspiration and radiosurgery has strong implications in improving patient outcomes

Unlocking the Inaccessible Energy Density of Sodium Vanadium Fluorophosphate Electrode Materials by Transition Metal Mixing

Sodium (Na) vanadium (V) fluorophosphate $\mathrm{Na_xV_2(PO_4)_2F_3}$ (NVPF) is a highly attractive intercalation electrode material due to its high operation voltage, large capacity, and long cycle life. However, several issues limit the full utilization of NVPF's energy density: 1) the high voltage plateau associated with extracting the "third" Na ion in the reaction N$_1$VPF $\rightarrow$ VPF (~4.9 V vs Na/Na$^+$) appears above the electrochemical stability window of most practical electrolytes (~4.5 V); 2) a sudden drop in Na-ion diffusivity is observed near composition $\mathrm{Na_1V_2(PO_4)_2F_3}$. Therefore, it is important to investigate the potential substitution of V by other transition metals in NVPF derivatives, which can access the extraction of the third Na-ion. In this work, we investigate the partial substitution of V with molybdenum (Mo), niobium (Nb), or tungsten (W) in NVPF to improve its energy density. We examine the structural and electrochemical behaviors of $\mathrm{Na_xV_{2-y}Mo_y(PO_4)_2F_3}$, $\mathrm{Na_xV_{2-y}Nb_y(PO_4)_2F_3}$, and $\mathrm{Na_xW_{2}(PO_4)_2F_3}$ across the whole Na composition region of 0 $\leq$ x $\leq$ 4, and at various transition metal substitution levels, namely, y=0.5, 1.0, 1.5, 2.0 for Mo, and y=1.0, 2.0 for Nb. We find that partial substitution of 50% V by Mo in NVPF reduces the voltage plateau for extracting the third Na ion by 0.6 Volts, which enables further Na extraction from $\mathrm{Na_1Mo_{2}(PO_4)_2F_3}$ and increases the theoretical gravimetric capacity from ~128 to ~174 mAh/g. Analysis of the migration barriers for Na-ions in $\mathrm{Na_xVMo(PO_4)_2F_3}$ unveils improved kinetic properties over NVPF. The proposed $\mathrm{Na_xVMo(PO_4)_2F_3}$ material provides an optimal gravimetric energy density of ~577.3 Wh/kg versus ~507 Wh/kg for the pristine NVPF, which amounts to an increase of ~13.9%

Clinical, histopathological, and molecular features of mucosa-associated lymphoid tissue (MALT) lymphoma carrying the t(X;14) (p11;q32)/GPR34-immunoglobulin heavy chain gene

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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

Traumatic brain injury causes selective, CD74-dependent peripheral lymphocyte activation that exacerbates neurodegeneration

INTRODUCTION: Traumatic brain injury (TBI), a significant cause of death and disability, causes, as in any injury, an acute, innate immune response. A key component in the transition between innate and adaptive immunity is the processing and presentation of antigen by professional antigen presenting cells (APCs). Whether an adaptive immune response to brain injury is beneficial or detrimental is not known. Current efforts to understand the contribution of the immune system after TBI have focused on neuroinflammation and brain-infiltrating immune cells. Here, we characterize and target TBI-induced expansion of peripheral immune cells that may act as potential APCs. Because MHC Class II-associated invariant peptide (CLIP) is important for antigen processing and presentation, we engineered a competitive antagonist (CAP) for CLIP, and tested the hypothesis that peptide competition could reverse or prevent neurodegeneration after TBI. RESULTS: We show that after fluid percussion injury (FPI), peripheral splenic lymphocytes, including CD4+ and CD8+ T cells, regulatory T cells (Tregs), and γδ T cells, are increased in number within 24 hours after FPI. These increases were reversed by CAP treatment and this antagonism of CLIP also reduced neuroinflammation and neurodegeneration after TBI. Using a mouse deficient for the precursor of CLIP, CD74, we observed decreased peripheral lymphocyte activation, decreased neurodegeneration, and a significantly smaller lesion size following TBI. CONCLUSION: Taken together, the data support the hypothesis that neurodegeneration following TBI is dependent upon antigen processing and presentation that requires CD74. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40478-014-0143-5) contains supplementary material, which is available to authorized users

Synthesis and Assembly of Nonspherical Hollow Silica Colloids Under Confinement

Hard peanut-shaped colloids were synthesized and organized into a degenerate crystal (DC), a phase previously observed only in simulations. In this structure, particle lobes tile a triangular lattice while their orientations uniformly populate the three underlying crystalline directions