A Novel Approach to Small Form-Factor Spacecraft Structures for Usage in Precision Optical Payloads

Precision optical payloads will soon experience a boom in manufacturing scale with the onset of proliferated satellite constellation concepts. Presently, the cost of assembly for a single unit can reach upwards of $500,000. Reduction in recurring engineering and assembly complexity can reduce this figure by up to two orders of magnitude. This paper discusses one potential solution which relies on consistent structural components that are easily manufactured in bulk quantities to facilitate general uses while also enabling high-precision mounting in designated payload slots. This proposed approach combines standardized struts and panels able to be connected and stacked in a variety of ways to form a modular structure from 1U subsections. For the subsections in need of higher precision, slots are milled and reamed from the same standard panel. Within these slots, card-like brackets are mounted to within 10 micrometer precision with the use of low-tolerance gauge spheres. A technique called “screw-pulling” secures these brackets such that the gauge spheres act as nearly single-point-of-contact datums. This approach allows payloads to be tested externally with minimal alignment shifts when re-integrated into the structure and is demonstrated with a 2.2 μm pixel size CMOS sensor and a 23 mm focal length lens

Optimized Compilation of Aggregated Instructions for Realistic Quantum Computers

Recent developments in engineering and algorithms have made real-world applications in quantum computing possible in the near future. Existing quantum programming languages and compilers use a quantum assembly language composed of 1- and 2-qubit (quantum bit) gates. Quantum compiler frameworks translate this quantum assembly to electric signals (called control pulses) that implement the specified computation on specific physical devices. However, there is a mismatch between the operations defined by the 1- and 2-qubit logical ISA and their underlying physical implementation, so the current practice of directly translating logical instructions into control pulses results in inefficient, high-latency programs. To address this inefficiency, we propose a universal quantum compilation methodology that aggregates multiple logical operations into larger units that manipulate up to 10 qubits at a time. Our methodology then optimizes these aggregates by (1) finding commutative intermediate operations that result in more efficient schedules and (2) creating custom control pulses optimized for the aggregate (instead of individual 1- and 2-qubit operations). Compared to the standard gate-based compilation, the proposed approach realizes a deeper vertical integration of high-level quantum software and low-level, physical quantum hardware. We evaluate our approach on important near-term quantum applications on simulations of superconducting quantum architectures. Our proposed approach provides a mean speedup of $5\times$, with a maximum of $10\times$. Because latency directly affects the feasibility of quantum computation, our results not only improve performance but also have the potential to enable quantum computation sooner than otherwise possible.Comment: 13 pages, to apper in ASPLO

Toward a personal quantum computer

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 115-118).by Henry H.W. Chong.M.Eng

中国国货运动: 中国和英属马来亚的比较研究,1912-1941 = A Comparative Study of Chinese National Product Movements: China and British Malaya, 1912-1941

Master'sMASTER OF ART

3D microfilter device for viable circulating tumor cell (CTC) enrichment from blood

Detection of circulating tumor cells has emerged as a promising minimally invasive diagnostic and prognostic tool for patients with metastatic cancers. We report a novel three dimensional microfilter device that can enrich viable circulating tumor cells fromblood. This device consists of two layers of parylene membrane with pores and gap precisely defined with photolithography. The positions of the pores are shifted between the top and bottom membranes. The bottom membrane supports captured cells and minimize the stress concentration on cell membrane and sustain cell viability during filtration. Viable cell capture on device was investigated with scanning electron microscopy, confocal microscopy, and immunofluorescent staining using model systems of cultured tumor cells spiked in blood or saline. The paper presents and validates this new 3D microfiltration concept for circulation tumor cell enrichment application. The device provides a highly valuable tool for assessing and characterizing viable enriched circulating tumor cells in both research and clinical settings

Oxygen environment and islet size are the primary limiting factors of isolated pancreatic islet survival

Background: Type 1 diabetes is an autoimmune disease that destroys insulin-producing beta cells in the pancreas. Pancreatic islet transplantation could be an effective treatment option for type 1 diabetes once several issues are resolved, including donor shortage, prevention of islet necrosis and loss in pre- and post-transplantation, and optimization of immunosuppression. This study seeks to determine the cause of necrotic loss of isolated islets to improve transplant efficiency. Methodology: The oxygen tension inside isolated human islets of different sizes was simulated under varying oxygen environments using a computational in silico model. In vitro human islet viability was also assessed after culturing in different oxygen conditions. Correlation between simulation data and experimentally measured islet viability was examined. Using these in vitro viability data of human islets, the effect of islet diameter and oxygen tension of the culture environment on islet viability was also analyzed using a logistic regression model. Principal findings: Computational simulation clearly revealed the oxygen gradient inside the islet structure. We found that oxygen tension in the islet core was greatly lower (hypoxic) than that on the islet surface due to the oxygen consumption by the cells. The hypoxic core was expanded in the larger islets or in lower oxygen cultures. These findings were consistent with results from in vitro islet viability assays that measured central necrosis in the islet core, indicating that hypoxia is one of the major causes of central necrosis. The logistic regression analysis revealed a negative effect of large islet and low oxygen culture on islet survival. Conclusions/Significance: Hypoxic core conditions, induced by the oxygen gradient inside islets, contribute to the development of central necrosis of human isolated islets. Supplying sufficient oxygen during culture could be an effective and reasonable method to maintain isolated islets viable

Vision impossible

Vision Impossible was designed to help promote vision awareness to the general public as well as to help bring various health professions together and educate them as to the different visual demands that each profession may experience. Vision Impossible was also intended to be a fundraising event to help raise money for the renovation of Jefferson Hall. Ninety-four subjects, consisting mainly of optometry students, took part in two trial runs of a ten-event course, designed to challenge the visual system in various ways. The trial runs were conducted at Pacific University and were used to assess the efficiency of the event design and data was collected for normative purposes. However, Vision Impossible was unable to implement the originally designed fundraising event. Factors which contributed to this included flaws with some of the event designs as well as unavailability of equipment, inability to obtain donations for prize incentives, and logistical problems concerning the event location and timing. However, Vision Impossible did succeed in developing a final course design as well as obtaining normative results for these course events should this endeavor be attempted in the future

Picosecond X-ray Absorption Spectroscopy of Photochemical Transient Species in Solution

A photoinduced Fe(II) spin crossover reaction in solution is studied with ultrafast x-ray absorption spectroscopy. The iron-nitrogen bond lengthens by 0.21+-0.03 Angstrom in the high-spin transient excited state relative to the ground state

Accurate neonatal heart rate monitoring using a new wireless, cap mounted device

© 2020 The Authors. Acta Paediatrica published by John Wiley & Sons Ltd on behalf of Foundation Acta Paediatrica Aim: A device for newborn heart rate (HR) monitoring at birth that is compatible with delayed cord clamping and minimises hypothermia risk could have advantages over current approaches. We evaluated a wireless, cap mounted device (fhPPG) for monitoring neonatal HR. Methods: A total of 52 infants on the neonatal intensive care unit (NICU) and immediately following birth by elective caesarean section (ECS) were recruited. HR was monitored by electrocardiogram (ECG), pulse oximetry (PO) and the fhPPG device. Success rate, accuracy and time to output HR were compared with ECG as the gold standard. Standardised simulated data assessed the fhPPG algorithm accuracy. Results: Compared to ECG HR, the median bias (and 95% limits of agreement) for the NICU was fhPPG −0.6 (−5.6, 4.9) vs PO −0.3 (−6.3, 6.2) bpm, and ECS phase fhPPG −0.5 (−8.7, 7.7) vs PO −0.1 (−7.6, 7.1) bpm. In both settings, fhPPG and PO correlated with paired ECG HRs (both R2=0.89). The fhPPG HR algorithm during simulations demonstrated a near-linear correlation (n=1266, R2=0.99). Conclusion: Monitoring infants in the NICU and following ECS using a wireless, cap mounted device provides accurate HR measurements. This alternative approach could confer advantages compared with current methods of HR assessment and warrants further evaluation at birth