Microelectromechanical Systems (MEMS) Resistive Heaters as Circuit Protection Devices

With increased opportunities for the exploitation (i.e., reverse engineering) of vulnerable electronic components and systems, circuit protection has become a critical issue. Circuit protection techniques are generally software-based and include cryptography (encryption/decryption), obfuscation of codes, and software guards. Examples of hardware-based circuit protection include protective coatings on integrated circuits, trusted foundries, and macro-sized components that self-destruct, thus destroying critical components. This paper is the first to investigate the use of microelectromechanical systems (MEMS) to provide hardware-based protection of critical electronic components to prevent reverse engineering or other exploitation attempts. Specifically, surface-micromachined polycrystalline silicon to be used as meandering resistive heaters were designed analytically and fabricated using a commercially available MEMS prototyping service (i.e., PolyMUMPs), and integrated with representative components potentially at risk for exploitation, in this case pseudomorphic high-electron mobility transistors (pHEMTs). The MEMS heaters were initiated to self-destruct, destroying a critical circuit component and thwart a reverse engineering attempt. Tests revealed reliable self-destruction of the MEMS heaters with approximately 25 V applied, resulting in either complete operational failure or severely altering the pHEMT device physics. The prevalent failure mechanism was metallurgical, in that the material on the surface of the device was changed, and the specific failure mode was the creation of a short-circuit. Another failure mode was degraded device operation due to permanently altered device physics related to either dopant diffusion or ohmic contact degradation. The results, in terms of the failure of a targeted electronic component, demonstrate the utility of using MEMS devices to protect critical components which are otherwise vulnerable to exploitation

Novel Microelectromechanical Systems Image Reversal Fabrication Process Based on Robust SU-8 Masking Layers

This paper discusses a novel fabrication process that uses a combination of negative and positive photoresists with positive tone photomasks, resulting in masking layers suitable for bulk micromachining high-aspect ratio microelectromechanical systems (MEMS) devices. MicroChem\u27s negative photoresist Nano™ SU-8 and Clariant\u27s image reversal photoresist AZ 5214E are utilized, along with a barrier layer, to effectively convert a positive photomask into a negative image. This technique utilizes standard photolithography chemicals, equipment, and processes, and opens the door for creating complementary MEMS structures without added fabrication delay and cost. Furthermore, the SU-8 masking layer is robust enough to withstand aggressive etch chemistries needed for fabrication research and development, bulk micromachining high-aspect ratio MEMS structures in silicon substrates, etc. This processing technique was successfully demonstrated by translating a positive photomask to an SU-8 layer that was then utilized as an etching mask for a series of trenches that were micromachined into a silicon substrate. In addition, whereas the SU-8 mask would normally be left in place after processing, a technique utilizing Rohm and Haas Microposit™ S1818 as a release layer has been developed so that the SU-8 masking material can be removed post-etching

Tests of sunspot number sequences: 1. Using ionosonde data

More than 70 years ago it was recognised that ionospheric F2-layer critical frequencies [foF2] had a strong relationship to sunspot number. Using historic datasets from the Slough and Washington ionosondes, we evaluate the best statistical fits of foF2 to sunspot numbers (at each Universal Time [UT] separately) in order to search for drifts and abrupt changes in the fit residuals over Solar Cycles 17-21. This test is carried out for the original composite of the Wolf/Zürich/International sunspot number [R], the new “backbone” group sunspot number [RBB] and the proposed “corrected sunspot number” [RC]. Polynomial fits are made both with and without allowance for the white-light facular area, which has been reported as being associated with cycle-to-cycle changes in the sunspot number - foF2 relationship. Over the interval studied here, R, RBB, and RC largely differ in their allowance for the “Waldmeier discontinuity” around 1945 (the correction factor for which for R, RBB and RC is, respectively, zero, effectively over 20 %, and explicitly 11.6 %). It is shown that for Solar Cycles 18-21, all three sunspot data sequences perform well, but that the fit residuals are lowest and most uniform for RBB. We here use foF2 for those UTs for which R, RBB, and RC all give correlations exceeding 0.99 for intervals both before and after the Waldmeier discontinuity. The error introduced by the Waldmeier discontinuity causes R to underestimate the fitted values based on the foF2 data for 1932-1945 but RBB overestimates them by almost the same factor, implying that the correction for the Waldmeier discontinuity inherent in RBB is too large by a factor of two. Fit residuals are smallest and most uniform for RC and the ionospheric data support the optimum discontinuity multiplicative correction factor derived from the independent Royal Greenwich Observatory (RGO) sunspot group data for the same interval

Towards a Critical Sociology of Dominant Ideologies: An Unexpected Reunion between Pierre Bourdieu and Luc Boltanski

This article aims to demonstrate the enduring relevance of Pierre Bourdieu and Luc Boltanski’s ‘La production de l’idéologie dominante’ [‘The production of the dominant ideology’], which was originally published in Actes de la recherche en sciences sociales in 1976. More than three decades later, in 2008, a re-edited version of this study was printed in book format as La production de l’idéologie dominante, which was accompanied by a detailed commentary, written by Luc Boltanski and entitled Rendre la réalité inacceptable. À propos de « La production de l’idéologie dominante » [Making Reality Unacceptable. Comments on ‘The production of the dominant ideology’]. In addition to containing revealing personal anecdotes and providing important sociological insights, this commentary offers an insider account of the genesis of one of the most seminal pieces Boltanski co-wrote with his intellectual father, Bourdieu. In the Anglophone literature on contemporary French sociology, however, the theoretical contributions made both in the original study and in Boltanski’s commentary have received little – if any – serious attention. This article aims to fill this gap in the literature, arguing that these two texts can be regarded not only as forceful reminders of the fact that the ‘dominant ideology thesis’ is far from obsolete but also as essential for understanding both the personal and the intellectual underpinnings of the tension-laden relationship between Bourdieu and Boltanski. Furthermore, this article offers a critical overview of the extent to which the unexpected, and partly posthumous, reunion between ‘the master’ (Bourdieu) and his ‘dissident disciple’ (Boltanski) equips us with powerful conceptual tools, which, whilst illustrating the continuing centrality of ‘ideology critique’, permit us to shed new light on key concerns in contemporary sociology and social theory. Finally, the article seeks to push the debate forward by reflecting upon several issues that are not given sufficient attention by Bourdieu and Boltanski in their otherwise original and insightful enquiry into the complexities characterizing the daily production of ideology

Pathogenic Huntingtin Repeat Expansions in Patients with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.

We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40-64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington's disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

Association of Variants in the SPTLC1 Gene With Juvenile Amyotrophic Lateral Sclerosis

Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.Objective: To identify the genetic variants associated with juvenile ALS.Design, Setting, and Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism.Main Outcomes and Measures: De novo variants present only in the index case and not in unaffected family members.Results: Trio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.Conclusions and Relevance: These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.</p

Using Positive Photomasks to Pattern SU-8 Masking Layers for Fabricating Inverse MEMS Structures

This paper discusses a novel processing technique that uses a combination of negative and positive photoresists for use with positive photomasks, resulting in masking layers suitable for bulk micromachining in the fabrication of microelectromechanical systems (MEMS). MicroChem\u27s negative photoresist Nano(TM) SU-8 and Clariant\u27s image reversal photoresist AZ 5214E are utilized, along with a barrier layer, to effectively convert a positive photomask into a negative photomask. This technique allows for the use of positive photomasks with negative resists, which opens the door to the ability to create complementary mechanical structures without the fabrication delays and cost associated with having to obtain a negative photomask. Furthermore, the SU-8 mask created is robust enough to withstand the bulk micromachining and aggressive etch chemistries needed to create MEMS structures. This processing technique was successfully demonstrated by translating a positive photomask to an SU-8 layer that was then utilized as a mask to etch trenches and other features into a silicon substrate

Fabrication Process Comparison and Dynamics Evaluation of Electrothermal Actuators for a Prototype MEMS Safe and Arming Devices

Electrothermal actuators fabricated using the Polysilicon Multi-User MEMS Process (PolyMUMPs) and the Sandia Ultra-Planar, Multi-Level MEMS Technology 5 (SUMMiT V) have been investigated for use in integrated microelectromechanical systems (MEMS) safe and arming devices. The fabricated electrothermal actuators have been dynamically tested to determine and compare the responses of devices from both processes. Furthermore, the integration of these devices into a safe and arming device were tested and investigated for each process. Initial results indicate that the SUMMiT devices provide the most optimum results based on consistency of operation and reliability