Automated Mixed Traffic Vehicle (AMTV) technology and safety study

Technology and safety related to the implementation of an Automated Mixed Traffic Vehicle (AMTV) system are discussed. System concepts and technology status were reviewed and areas where further development is needed are identified. Failure and hazard modes were also analyzed and methods for prevention were suggested. The results presented are intended as a guide for further efforts in AMTV system design and technology development for both near term and long term applications. The AMTV systems discussed include a low speed system, and a hybrid system consisting of low speed sections and high speed sections operating in a semi-guideway. The safety analysis identified hazards that may arise in a properly functioning AMTV system, as well as hardware failure modes. Safety related failure modes were emphasized. A risk assessment was performed in order to create a priority order and significant hazards and failure modes were summarized. Corrective measures were proposed for each hazard

Mastl kinase, a promising therapeutic target, promotes cancer recurrence.

Mastl kinase promotes mitotic progression and cell cycle reentry after DNA damage. We report here that Mastl is frequently upregulated in various types of cancer. This upregulation was correlated with cancer progression in breast and oral cancer, poor patient survival in breast cancer, and tumor recurrence in head and neck squamous cell carcinoma. We further investigated the role of Mastl in tumor resistance using cell lines derived from the initial and recurrent tumors of the same head and neck squamous cell carcinoma patients. Ectopic expression of Mastl in the initial tumor cells strongly promoted cell proliferation in the presence of cisplatin by attenuating DNA damage signaling and cell death. Mastl knockdown in recurrent tumor cells re-sensitized their response to cancer therapy in vitro and in vivo. Finally, Mastl targeting specifically potentiated cancer cells to cell death in chemotherapy while sparing normal cells. Thus, this study revealed that Mastl upregulation is involved in cancer progression and tumor recurrence after initial cancer therapy, and validated Mastl as a promising target to increase the therapeutic window

Fabrication and characterization of novel nanostructures based on block copolymer lithography

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.Cataloged from PDF version of thesis.Includes bibliographical references.Microphase-separation of block copolymers into periodic nanoscale structures has drawn considerable attention as a method for pattern generation in nanolithography. One of the main challenges is to create complex nanostructures other than closed-packed nanodots or nanoholes with hexagonal symmetry, or parallel nanolines based on block copolymer lithography. In this thesis, we demonstrate two approaches to generate novel structures such as ellipsoids, rings or square array of dots: diblock copolymers templating and triblock terpolymers. Without templating, diblock copolymer can only form spheres, cylinders, or lamellae typically. Triblock terpolymers, on the other hand, can form a larger number of morphologies even without using any template. The use of triblock terpolymers allows the formation of more complex pattern geometries compared to their diblock counterparts. Moreover, since most features in this thesis are made from an organometallic block, they have a high etch contrast and etch resistance compared to triblock terpolymers in which all three blocks contains organic segments, making them useful for pattern transfer. Rings are useful in the magnetic applications, quantum devices, and biosensors. Square symmetry array, which is not found in diblock copolymers, has applications in via formation, magnetic patterned media, and other applications. Besides, we examine the magnetic behavior of the antidot arrays of Co and pseudo-spin-valve structures with periodicity of 26 nm and 40 nm.(cont.) As the inter-hole spacing is decreased, both experiment and simulation results show that the coercivity and switching field distribution is reduced, unlike the behavior seen in films with micron- sized holes. In the multilayer, unlike the continuous film, the NiFe reverses at positive fields due to the strong magnetostatic interactions between the Co and NiFe layers present near the holes. Finally, arrays of high-aspect-ratio single crystal silicon nanowires (SiNWs) have also been fabricate by combining block copolymer lithography and metal assisted etching. These SiNWs may be useful in the application of field-effect biosensors and lithium batteries.by Vivian Peng-Wei Chuang.Ph.D

Bioelectronic DNA detection of human papillomaviruses using eSensor™: a model system for detection of multiple pathogens

BACKGROUND: We used human papillomaviruses (HPV) as a model system to evaluate the utility of a nucleic acid, hybridization-based bioelectronic DNA detection platform (eSensor™) in identifying multiple pathogens. METHODS: Two chips were spotted with capture probes consisting of DNA oligonucleotide sequences specific for HPV types. Electrically conductive signal probes were synthesized to be complementary to a distinct region of the amplified HPV target DNA. A portion of the HPV L1 region that was amplified by using consensus primers served as target DNA. The amplified target was mixed with a cocktail of signal probes and added to a cartridge containing a DNA chip to allow for hybridization with complementary capture probes. RESULTS: Two bioelectric chips were designed and successfully detected 86% of the HPV types contained in clinical samples. CONCLUSIONS: This model system demonstrates the potential of the eSensor platform for rapid and integrated detection of multiple pathogens

Overexpression of matrix metalloproteinase 9 in tumor epithelial cells correlates with colorectal cancer metastasis.

Colorectal cancer mortality largely reflects metastasis, the spread of the disease to distant organs. Matrix metalloproteinase 9 (MMP-9) is a key regulator of metastasis and a target for anticancer strategies in colon cancer. Here, the overexpression of MMP-9 in pure tumor epithelial, but nor stromal, cell populations was associated with metastatic progression of colorectal cancer, as defined by reverse transcriptase-polymerase chain reaction (qRT-PCR) and confirmed by immunostaining. Thus, cancer cell MMP-9 represents a novel, selective prognostic and predictive factor that may be exploited for more effective disease stage stratification and therapeutic regimen selection in patients with colorectal cancer

Transcriptome analysis of Aspergillus niger xlnR and xkiA mutants grown on corn Stover and soybean hulls reveals a highly complex regulatory network.

BACKGROUND:Enzymatic plant biomass degradation by fungi is a highly complex process and one of the leading challenges in developing a biobased economy. Some industrial fungi (e.g. Aspergillus niger) have a long history of use with respect to plant biomass degradation and for that reason have become 'model' species for this topic. A. niger is a major industrial enzyme producer that has a broad ability to degrade plant based polysaccharides. A. niger wild-type, the (hemi-)cellulolytic regulator (xlnR) and xylulokinase (xkiA1) mutant strains were grown on a monocot (corn stover, CS) and dicot (soybean hulls, SBH) substrate. The xkiA1 mutant is unable to utilize the pentoses D-xylose and L-arabinose and the polysaccharide xylan, and was previously shown to accumulate inducers for the (hemi-)cellulolytic transcriptional activator XlnR and the arabinanolytic transcriptional activator AraR in the presence of pentoses, resulting in overexpression of their target genes. The xlnR mutant has reduced growth on xylan and down-regulation of its target genes. The mutants therefore have a similar phenotype on xylan, but an opposite transcriptional effect. D-xylose and L-arabinose are the most abundant monosaccharides after D-glucose in nearly all plant-derived biomass materials. In this study we evaluated the effect of the xlnR and xkiA1 mutation during growth on two pentose-rich substrates by transcriptome analysis. RESULTS:Particular attention was given to CAZymes, metabolic pathways and transcription factors related to the plant biomass degradation. Genes coding for the main enzymes involved in plant biomass degradation were down-regulated at the beginning of the growth on CS and SBH. However, at a later time point, significant differences were found in the expression profiles of both mutants on CS compared to SBH. CONCLUSION:This study demonstrates the high complexity of the plant biomass degradation process by fungi, by showing that mutant strains with fairly straightforward phenotypes on pure mono- and polysaccharides, have much less clear-cut phenotypes and transcriptomes on crude plant biomass

Brine assemblages of ultrasmall microbial cells within the ice cover of Lake Vida, Antarctica

The anoxic and freezing brine that permeates Lake Vida\u27s perennial ice below 16mcontains an abundance of very small (≤0.2-μm) particles mixed with a less abundant population of microbial cells ranging from\u3e0.2 to 1.5 μmin length. Fluorescent DNA staining, electron microscopy (EM) observations, elemental analysis, and extraction of high-molecular-weight genomic DNA indicated that a significant portion of these ultrasmall particles are cells. A continuous electron-dense layer surrounding a less electron-dense region was observed by EM, indicating the presence of a biological membrane surrounding a cytoplasm. The ultrasmall cells are 0.192±0.065 μ, with morphology characteristic of coccoid and diplococcic bacterial cells, often surrounded by iron-rich capsular structures. EM observations also detected the presence of smaller unidentified nanoparticles of 0.020 to 0.140 μmamong the brine cells. A 16S rRNA gene clone library from the brine 0.1- to 0.2-μm-size fraction revealed a relatively low-diversity assemblage of Bacteria sequences distinct from the previously reported\u3e0.2-μm-cell-size Lake Vida brine assemblage. The brine 0.1- to 0.2-μm-size fraction was dominated by the Proteobacteria-affiliated genera Herbaspirillum, Pseudoalteromonas, and Marinobacter. Cultivation efforts of the 0.1- to 0.2-μm-size fraction led to the isolation of Actinobacteria-affiliated genera Microbacterium and Kocuria. Based on phylogenetic relatedness and microscopic observations, we hypothesize that the ultrasmall cells in Lake Vida brine are ultramicrocells that are likely in a reduced size state as a result of environmental stress or life cycle-related conditions. © 2014, American Society for Microbiology

The impact of surgical repair on left ventricular outflow tract in atrioventricular septal defect with common atrioventricular valve orifice

Objective: Although a narrow left ventricular outflow tract (LVOT) in atrioventricular septal defect (AVSD) is related to its intrinsic morphology, the contribution from repair technique remains to be quantified. Methods: 108 AVSD patients with common atrio-ventricular valve orifice were divided into 2 groups: two-patch (N=67) and modified 1-patch (N=41) repair. LVOT morphometric was analysed by quantifying the degree of disproportion between subaortic:aortic annular dimensions (disproportionate morphometrics ratio was defined as ≤ 0.9). Z-scores (median, interquartile range) were further analysed in a subset of 80 patients with immediate pre- and post-operative echocardiography. 44 subjects with VSD served as controls. Results: Pre-repair, 13(12%) AVSD had disproportionate morphometrics (vs 6(14%) VSD p=0.79); but subaortic Z-score (-0.53, -1.07 - 0.06) was lower than VSD (0.07, -0.57 - 1.17; p<0.001). Post-repair, both two-patch (8(12%) pre-op vs 25(37%) post-op; p=0.001) and modified 1-patch (5(12%) vs 21(51%), p<0.001) showed greater degree of disproportionate morphometrics. Both two-patch (post-op -0.73, -1.56 - 0.08 vs pre-op -0.43, -0.98 - 0.28; p=0.011) and modified 1-patch (-1.42, -2.63-(-0.78) vs -0.70, -1.18 - (-0.25); p=0.001) also had lower subaortic z-scores post-repair. The post-repair subaortic z-scores were lower in modified 1-patch [-1.42 (-2.63 - (-0.78)] compared to two-patch [-0.73 (-1.56 - 0.08); p=0.004]. Low post-repair subaortic Z-scores (under -2) were observed in 12(41%) modified 1-patch and 6(12%) two-patch (p=0.004). Conclusions: Surgical correction resulted in greater disproportionate morphometrics seen immediately post-repair. The impact on the LV outflow tract was observed in all repair techniques, with a greater burden seen following modified 1-patch repair