A Monolithically Fabricated Combinatorial Mixer for Microchip-Based High-Throughput Cell Culturing Assays

We present an integrated method to fabricate 3- D microfluidic networks and fabricated the first on-chip cell culture device with an integrated combinatorial mixer. The combinatorial mixer is designed for screening the combinatorial effects of different compounds on cells. The monolithic fabrication method with parylene C as the basic structural material allows us to avoid wafer bonding and achieves precise alignment between microfluidic channels. As a proof-of-concept, we fabricated a device with a three-input combinatorial mixer and demonstrated that the mixer can produce all the possible combinations. Also, we demonstrated the ability to culture cells on-chip and performed a simple cell assay on-chip using trypan blue to stain dead cells

Attenuation of Cellular Inflammation Using Glucocorticoid-Functionalized Copolymers

This work has demonstrated the functionalization of an amphiphilic diblock copolymer, comprised of polyethylene oxide-polymethyl methacrylate (PEO-PMMA), as well as a triblock copolymer comprised of polymethyloxazoline-polydimethylsiloxane-polymethyloxazoline(PMOXA-PDMS-PM OXA) with the dexamethasone (Dex) glucocorticoid anti-inflammatory. Interfacial deposition of the copolymer and the Dex molecules and subsequent transfer of the hybrid materials to solid substrates were characterized to evaluate the potential of utilizing this composite material as a suppressor of cyto-inflammation to enhance implant biocompatibility. Given the extremely thin dimensions of the film (~4nm), this material would have negligible impact upon the size of the coated device to preclude biological stress. The composite films were interfaced with the RAW264.7 murine macrophages which served as a model cell line for the evaluation of nuclear factor-kappaB (NF-KB)-induced production of a host of inflammatory cytokines including interleukin-6, interleukin-12, tumor necrosis factor-alpha (TNFalpha), as well as the inducible nitric oxide synthase signaling factor which is known to be involved with stress-related processes such as neuronal damage. Lipopolysaccharide or LPS is a component of bacterial membranes that elicits cellular stress following application to RAW cell cultures. Following the induced stress response, significant reductions in the expression of genes associated with the aforementioned cytokines and signaling molecules indicated that macrophages in direct contact with the functionalized copolymer were able to collect Dex that was released from within the polymer network to attenuate cyto-inflammation mechanisms. This composite membrane represents a medically-relevant technology to promote chronic implant functionality and preclusion of bio-fouling

Outcome prediction in metabolic dysfunction-associated steatotic liver disease using stain-free digital pathological assessment

Computational quantification reduces observer-related variability in histological assessment of metabolic dysfunction-associated steatotic liver disease (MASLD). We undertook stain-free imaging using the SteatoSITE resource to generate tools directly predictive of clinical outcomes. Unstained liver biopsy sections (n=452) were imaged using second harmonic generation/two-photon excitation fluorescence microscopy, and all-cause mortality and hepatic decompensation indices constructed. The mortality index had greater predictive power for all-cause mortality (index >0.14 vs. </=0.14, HR 4.49, p=0.003) than NASH-CRN (HR 3.41, 95% CI 1.43-8.15, p=0.003) and qFibrosis stage (HR 3.07, 95% CI 1.30-7.26, p=0.007). The decompensation index had greater predictive power for decompensation events (index >0.31 vs. </=0.31, HR 5.96, p<0.001) than NASH-CRN (HR 3.65, 95% CI 1.81-7.35, p<0.001) or qFibrosis stage (HR 3.59, 95% CI 1.79-7.20, p<0.001). These tools directly predict hard endpoints in MASLD, without relying on ordinal fibrosis scores as a surrogate, and demonstrate predictive value at least equivalent to traditional or computational ordinal fibrosis scores

Monolithic 3-D Microfluidic Device for Cell Assay with an Integrated Combinatorial Mixer

We present a novel cell culture device with an integrated 3-D microfluidic mixer for screening the combinatorial effects of multiple compounds on cultured cells and demonstrated the ability to simultaneously treat arrays of cells with different combinations of compounds. The proof-of-concept chip, which has a three-input combinatorial mixer with eight micro culture chambers, was monolithically fabricated utilizing the surface micromaching of parylene C (poly-para-xylylene C). By having several microfluidic "overpasses" to allow one microfluidic channel to cross over other microfluidic channels, the combinatorial mixer was able to simultaneously generate all the combinations of the input fluidic streams for output to the microchambers. We verified that parylene C is a biocompatible substrate for cell culturing and also showed cell culturing inside the micro culture chambers. The feasibility of using the integrated combinatorial mixer for cell assaying was demonstrated with experiments using three different cell stains, and results showed the cells in different chambers were stained with varying color patterns

The Relationships Between Fluoride Intake Levels and Fluorosis of Late‐Erupting Permanent Teeth

Objectives To examine the relationships between fluoride intake levels and fluorosis of late‐erupting permanent teeth. Methods The current study used information collected from 437 children in the longitudinal Iowa Fluoride Study. Participants\u27 fluoride intake information was collected using questionnaires from birth to age 10 years. Estimated mean daily fluoride intake was categorized into low, moderate, and high intake tertiles for each age interval (2‐5, 5‐8, and 2‐8 years). Bivariate analyses were performed to study the relationships between self‐reported fluoride intake levels during three age intervals and dental fluorosis. Results For canines and second molars, the prevalence of mostly mild fluorosis was less than 10% in the lowest fluoride intake tertile and more than 25% in the highest intake tertile. For both first and second premolars, the prevalence in the low and high intake tertiles was approximately 10‐15% and 25‐40%, respectively. When estimated total daily fluoride intake was 0.04 mg/kg BW during ages 2‐8 years, the predicted probability of fluorosis was 16.0%, 20.5%, 21.8%, and 15.4% for canines, 1st and 2nd and premolars and 2nd molars, respectively. We found that an incremental increase in fluoride intake during the age 5‐ to 8‐year interval led to greater odds for development of mostly mild dental fluorosis in late‐erupting teeth compared to increases in fluoride intake during other age intervals. Conclusions Our results clearly show that dental fluorosis prevalence is closely related to fluoride intake levels and that teeth have greater susceptibility to fluoride intake during certain age intervals

Exploration of the Security and Usability of the FIDO2 Authentication Protocol

Gemstone Team PASSFast IDentity Online (FIDO) is a passwordless authentication protocol for the web that leverages public key cryptography and trusted devices to avoid shared secrets on servers. The current version of FIDO, FIDO2, has become widespread and is directly integrated into popular systems such as Windows Hello and Android OS. This thesis details two contributions to the advancement of FIDO2. The first is a modification to the protocol which uses Trusted Execution Environments to resolve security vulnerabilities in the Client To Authenticator Protocol Version 2 (CTAP2), which is a component of FIDO2. It is formally demonstrated that this modification provides a stronger security assumption than CTAP2. The second contribution is an outline of procedures and resources for future researchers to carry out a study of the usability of FIDO2 authenticators via a within-subjects experiment. In the study, subjects register an account on a custom web app using both passwords and FIDO2 credentials. The web app collects metrics about user behavior such as timing information for authentication sessions. Over the course of a week, subjects log in to the same web app every day using both authentication methods. Subjects complete entrance and exit surveys based on the System Usability Scale (SUS) according to their experiences. The surveys and user metrics would then be analyzed to determine whether users perceive FIDO2 as more usable than passwords

Intraneuronal Aβ detection in 5xFAD mice by a new Aβ-specific antibody

<p>Abstract</p> <p>Background</p> <p>The form(s) of amyloid-β peptide (Aβ) associated with the pathology characteristic of Alzheimer's disease (AD) remains unclear. In particular, the neurotoxicity of intraneuronal Aβ accumulation is an issue of considerable controversy; even the existence of Aβ deposits within neurons has recently been challenged by Winton and co-workers. These authors purport that it is actually intraneuronal APP that is being detected by antibodies thought to be specific for Aβ. To further address this issue, an anti-Aβ antibody was developed (MOAB-2) that specifically detects Aβ, but not APP. This antibody allows for the further evaluation of the early accumulation of intraneuronal Aβ in transgenic mice with increased levels of human Aβ in 5xFAD and 3xTg mice.</p> <p>Results</p> <p>MOAB-2 (mouse IgG_2b) is a pan-specific, high-titer antibody to Aβ residues 1-4 as demonstrated by biochemical and immunohistochemical analyses (IHC), particularly compared to 6E10 (a commonly used commercial antibody to Aβ residues 3-8). MOAB-2 did not detect APP or APP-CTFs in cell culture media/lysates (HEK-APP_Sweor HEK-APP_Swe/BACE1) or in brain homogenates from transgenic mice expressing 5 familial AD (FAD) mutation (5xFAD mice). Using IHC on 5xFAD brain tissue, MOAB-2 immunoreactivity co-localized with C-terminal antibodies specific for Aβ40 and Aβ42. MOAB-2 did not co-localize with either N- or C-terminal antibodies to APP. In addition, no MOAB-2-immunreactivity was observed in the brains of 5xFAD/BACE^-/-mice, although significant amounts of APP were detected by N- and C-terminal antibodies to APP, as well as by 6E10. In both 5xFAD and 3xTg mouse brain tissue, MOAB-2 co-localized with cathepsin-D, a marker for acidic organelles, further evidence for intraneuronal Aβ, distinct from Aβ associated with the cell membrane. MOAB-2 demonstrated strong intraneuronal and extra-cellular immunoreactivity in 5xFAD and 3xTg mouse brain tissues.</p> <p>Conclusions</p> <p>Both intraneuronal Aβ accumulation and extracellular Aβ deposition was demonstrated in 5xFAD mice and 3xTg mice with MOAB-2, an antibody that will help differentiate intracellular Aβ from APP. However, further investigation is required to determine whether a molecular mechanism links the presence of intraneuronal Aβ with neurotoxicity. As well, understanding the relevance of these observations to human AD patients is critical.</p

Interplay between local moment and itinerant magnetism in the layered metallic antiferromagnet TaFe1.14_{1.14}Te3_3

Two-dimensional (2D) antiferromagnets have garnered considerable interest for the next generation of functional spintronics. However, many available bulk materials from which 2D antiferromagnets are isolated are limited by their sensitivity to air, low ordering temperatures, and insulating transport properties. TaFe$_{1+y}$Te$_3$ offers unique opportunities to address these challenges with increased air stability, metallic transport properties, and robust antiferromagnetic order. Here, we synthesize TaFe$_{1+y}$Te$_3$ ($y$ = 0.14), identify its structural, magnetic, and electronic properties, and elucidate the relationships between them. Axial-dependent high-field magnetization measurements on TaFe$_{1.14}$Te$_3$ reveal saturation magnetic fields ranging between 27-30 T with a saturation magnetic moment of 2.05-2.12 $\mu_B$. Magnetotransport measurements confirm TaFe$_{1.14}$Te$_3$ is metallic with strong coupling between magnetic order and electronic transport. Angle-resolved photoemission spectroscopy measurements across the magnetic transition uncover a complex interplay between itinerant electrons and local magnetic moments that drives the magnetic transition. We further demonstrate the ability to isolate few-layer sheets of TaFe$_{1.14}$Te$_3$ through mechanical exfoliation, establishing TaFe$_{1.14}$Te$_3$ as a potential platform for 2D spintronics based on metallic layered antiferromagnets.Comment: 30 pages, 5 main figures, 23 supporting figures, and 3 supporting table

Aligning assessment with the needs of work-integrated learning: the challenges of authentic assessment in a complex context

Work-integrated learning (WIL) is a feature of university courses, both in professional areas, where it is commonplace, but also across many different disciplines. Assessment of WIL can be complex as it involves parties and settings external to the university, and it can be problematic because of difficulties in aligning learning activities during placements with what is or can be assessed by the university. This paper explores the relationship between students’ placement experiences and accompanying assessments in contexts where activities are tightly coupled with the curriculum, and in those where it is not. It draws on a qualitative analysis of student interviews and drawings by the interviewees of their WIL experiences, supplemented with analysis of unit guides. Our findings highlight that students’ perceptions of authenticity of assessment were undermined by misalignments between the student, university and industry. Assessment authenticity was perceived by students as based on alignment between their current and future selves in the assessment process, involvement of industry supervisors and relevance of placement activities to assessment activities. The paper discusses the complexity of coordination of educational activities with external partners, especially when one party drives assessment. It then suggests a reframing of WIL assessment to promote alignment and authenticity

Association Between Acid-Sensing Ion Channel 3 Gene Variants and Balance Impairment in People With Mild Traumatic Brain Injury

Introduction: Dizziness and balance impairment are common symptoms of mild traumatic brain injury (mTBI). Acid-sensing ion channel 3 (ASIC3) is expressed in the vestibular and proprioceptive systems and associated with balance functions. However, whether the genetic variants of ASIC3 are associated with people who suffer dizziness and balance impairment after mTBI remained unknown.Materials and methods: A total of 200 people with mTBI and 109 non-mTBI controls were recruited. Dizziness, balance functions, and the ability to perform daily activities were assessed by Dizziness Handicap Inventory (DHI), and objective balance functions were investigated by the postural stability test. Three diseases-related genetic variants of ASIC3 were determined through polymerase chain reaction and followed by restriction fragment length polymorphism. The Student's t-test and Mann-Whitney U-test were used for normal and abnormal distributed data, respectively. The regression was applied to adjust gender and age. The normality of continuous data was evaluated by Shapiro-Wilk test.Results: In the mTBI people, the rs2288645-A allele carriers exhibited a significantly worse physical domain DHI score (A-allele carriers: 11.39 ± 8.42, non-A carriers: 8.76 ± 7.87, p = 0.03). The rs4148855-GTC deletion carriers an exhibited significantly worse overall postural stability (GTC deletion carriers: 0.53 ± 0.33, non-carriers: 0.46 ± 0.20, p = 0.03). In the controls, rs2288646-A allele carriers were significant worse in the medial-to-lateral postural stability (A-allele carriers: 0.31 ± 0.17, non-A carriers: 0.21 ± 0.10, p = 0.01).Conclusion: The present study demonstrated that ASIC3 genetic variants were associated with certain aspects of balance functions and dizziness questionnaires in people of mTBI and non-mTBI. It provides a possible evidence that ASIC3 could be a new target for the management of the balancing disorders. However, further investigations are warranted to elucidate the underlying mechanisms and clinical significance