A perspective on migration and community engagement in Smart Cities

This is a conceptual paper interfacing community engagement and migration flows in relation to smart cities’ development. The paper notes community engagement as a crucial variable, in general and with reference to the aspired for impact on migration flows. It conceptualizes community engagement as an operationalizable construct for strategic design. The idea of community engagement is there in most multi-stakeholder projects and initiatives. Enhancing design and execution for making it count for superior performance of smart city initiatives is what we seek to develop here. The paper is also oriented to deliver an agenda for field research based on hypotheses it comes forth with

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Defect analysis using high throughput plasma FIB in packaging reliability investigations

Within this paper the application potential of a new fast Plasma FIB system for defect analysis regarding packaging reliability studies is evaluated. Depending on the material under investigation both the higher current and the higher sputter efficiency of the Xe significantly improve the range of application fields and/or the analysis throughput. This makes the Plasma FIB a very attractive tool for the analysis of relatively large interconnect structures without any need of mechanical preparation steps. We used the Plasma FIB to support reliability investigations for automotive and power electronics using heavy wire Aluminum bonded interconnects, die attach materials like Direct Copper Bonded Substrates (DCB) and lead-free soldered contacts. For all of these application cases specifically adapted preparation strategies have been investigated and applied to remove polishing artifacts by stepwise tilting the sample. It is demonstrated that Plasma-FIB milling significantly increases the efficiency and throughput and offers new approaches and more flexibility in sample preparation. Within the paper selected case studies regarding reliability investigations and failure analysis are presented. In addition, an assessment of the analysis throughput increase, of new extended application ranges and current limitations will be given

Reliability characterization of heavy wire bonding materials

Ultrasonic heavy wire bonding is one of the most relevant interconnection technologies in automotive and power electric devices. The reliability of electronic components in these fields is mainly determined by the interconnection lifetime during application and, thus by the strength and fatigue characteristics of the mechanically and thermo-mechanically loaded bonding wire materials. In the current paper, mechanical and micro structure properties of different heavy bonding wire materials including Al-, Cu- and Al-clad Cu wires are analyzed in their initial state prior to bonding. Fatigue properties were estimated in the form of the Coffin-Manson equation for the wires loaded in uniaxial cyclic testing. In addition, corresponding microstructure properties were investigated using Scanning Electron Microscopy (SEM) and Electron Backscattered Diffraction (EBSD). The applied approach aims at an improved understanding of basic material properties governing the general reliabi lity behavior of the wires independently from any specific application. The results obtained, enable a more detailed understanding of the material aspects governing the low cycle fatigue behavior of different heavy bonding wires. In particular, they provide an explanation for the superior life time behavior of Cu- and Al clad Cu wires compared to Al wires. In addition, the data derived support establishing improved and consistent quantitative life time models based on finite element analysis for different electronic devices

High resolution failure analysis of silver-sintered contact interfaces for power electronics

In this paper, results of failure analysis on silver-sintered chip backside and substrate contacts for power electronics modules using non-destructive Scanning Acoustic Microscopy (SAM), high resolution Scanning and Transmission Electron Microscopy (SEM, TEM) as well as Time-of-Flight Secondary Ion Mass Spectrometry (ToF SIMS) are presented. Specific attention is given to the microstructure of both contact interfaces, chip metallization to silver-sinter layer and silver-sinter layer to substrate metallization. In general, silver-sinter joints show an excellent bonding quality for most of the investigated chip and substrate metallization systems. Critical failure sites identified in this study are the formation of silver sulfide (Ag2S) at Ag-metallization/ Ag-sinter interfaces and contaminations on top of chip and substrate metallizations. Beside the interface issues, micro cracks and void like defects were detected within some specific chip and substrate metallization systems, respectively. Such defects can affect the strength properties and form a risk for both bonding quality and reliability

Microstructural study of the fatigue mechanism of aluminum cladded copper wires

Increasing challenges in the area of reliability of thermo-mechanically loaded electrical devices in automotive and power electronic components have led to the introduction of new interconnection technologies and materials. With respect to heavy wire bonding, new solutions based on innovative copper or aluminum-cladded copper wires have been presented and show significant potential for enhancing the lifetime of interconnections. However, newly observed lifetime-determining failure modes and types of damage evolution can differ significantly from those known from common aluminum wire bonding materials. Therefore, the present work gives an overview of observed defect processes and failure mechanisms by heel cracking in Al/Cu composite bond wires after thermally and mechanically fatigue experiments. In detail, the microstructure of the thermally and mechanically cycled specimens was analyzed using scanning electron microscopy (SEM) in combination with focused ion beam (FIB) preparation to investigate potential defect mechanisms. Identified micro-cracks formed at the cladding interface in the vicinity of the solid-state Cu/Al intermetallic phases (IMP) were analyzed by transmission electron microscopy (TEM) investigations in order to evaluate their relevance for fatigue mechanisms. Comparing the defect mechanisms and the local loading intensity calculated by the use of finite element analyses, a deeper insight into the failure mechanisms and failure modes for heel crack formation can be given

Test Methods for Characterizing the Local Plastic Deformability of Bonding Wires

Different methods for characterizing the local plastic deformability of small Al bonding wire samples were presented including Vickers and spherical indentation as well as micro compression testing for two different sample orientations. The results were compared to reference data derived from tensile testing of macroscopic wire specimens and to the Al grain microstructure as characterized by the Electron Backscatter Diffraction (EBSD) method. A close correlation between tensile wire strength, hardness data and grain size was found. This relationship can be used to evaluate local changes in the wire material properties due to the influence of process steps or application conditions. In addition, the potential and high accuracy of the newly developed micro compression test was demonstrated. Stress-strain curves derived from micro compression testing agreed well with the reference data in most cases. In so far, the micro compression test can be used as a tool to quantify the local mechanical behaviour of processed bonding wires and bonded interconnects

Strategy to sequence the genome of Corynebacterium glutamicum ATCC 13032: use of a cosmid and a bacterial artificial chromosome library

Tauch A, Homann I, Mormann S, et al. Strategy to sequence the genome of Corynebacterium glutamicum ATCC 13032: use of a cosmid and a bacterial artificial chromosome library. JOURNAL OF BIOTECHNOLOGY. 2002;95(1):25-38.The initial strategy of the Corynebacterium glutamicum genome project was to sequence overlapping inserts of an ordered cosmid library. High-density colony grids of approximately 28 genome equivalents were used for the identification of overlapping clones by Southern hybridization. Altogether 18 contiguous genomic segments comprising 95 overlapping cosmids were assembled. Systematic shotgun sequencing of the assembled cosmid set revealed that only 2.84 Mb (86.6%) of the C glutamicum genome were represented by the cosmid library. To obtain a complete genome coverage, a bacterial artificial chromosome (BAC) library of the C. glutamicum chromosome was constructed in pBeloBAC11 and used for genome mapping. The BAC library consists of 3168 BACs and represents a theoretical 63-fold coverage of the C. glutamicum genome (3.28 Mb). Southern screening of 2304 BAC clones with PCR-amplified chromosomal markers and subsequent insert terminal sequencing allowed the identification of 119 BACs covering the entire chromosome of C. glutamicum. The minimal set representing a 100% genome coverage contains 44 unique BAC clones with an average overlap of 22 kb. A total of 21 BACs represented linking clones between previously sequenced cosmid contigs and provided a valuable tool for completing the genome sequence of C. glutamicum. (C) 2002 Elsevier Science B.V. All rights reserved