bluuebunny/crossref_metadata_2025 huggingface dataset:
Experience from Introducing Systems Engineering in an Academic Environment Using an Industry Training Course
Authors: Herzog Erik , Larsson Åsa Nordling , El‐Khoury Jad , Törngren Martin
Published: August 2018

Training and educating Systems Engineers is a key activity for any organization developing complex heterogeneous systems. Ideally, the regional/national academic community will provide courses and education programs facilitating for the needs of industry and society. However, Systems Engineering is not a traditional academic subject and despite the growing academic interest in the subject there are many regions with no dedicated academic courses and programs in the subject.

This paper presents experience from introducing Systems Engineering via a capstone project course in a mechatronics master's program at the Royal Institute of Technology (KTH) in Sweden. System engineers from industry give an industry‐developed Systems Engineering course, as part of a capstone course. We believe that the approach is novel and can serve as a mechanism for introducing Systems Engineering to both students and lecturers in the academic world, who have no previous exposure to the subject. Moreover, student feedback indicate that having lecturers with industrial experience was highly appreciated, making the activity a worthwhile branding investment for industry as well.
An Empirical Case Study of Problem Structuring in the Use of Generic Architectures
Authors: McLean James , Gilbert Dawn
Published: August 2018

An empirical case study is presented which details a problem structuring activity facilitated by the United Kingdom (UK) Ministry of Defence (MOD) Internal Technical Support ‐ Systems Engineering Team with the UK MOD Generic Vehicle Architecture (GVA) team. The body of literature reviewed identified an absence of specific guidance, or description of practical experience, in applying generic architectures to manage system change. The problem structuring activity allowed the GVA team to better understand the nature of the problem they faced, and to identify a means to effectively progress the issue. This case study is offered for consideration as the description of the problem situation may resonate with the reader, and to provoke thought on the methods used in selecting systems engineering methods to use in practice.
Technology Readiness Assessment for the Nuclear Weapons Program
Authors: Bell R. Glenn , Venkatesh Srini , Bruns Caroline W.
Published: August 2018

Technology development is typically the process of developing and demonstrating new or unproven technology, the application of existing technology to new or different uses, or the combination of existing and proven technology to achieve a specific goal. Technology development associated with a specific acquisition project for nuclear weapon typically should be identified early in the project life cycle and its maturity level should evolve to a confidence level that allows the project to establish a credible technical scope, schedule, and cost baseline. Projects that perform concurrent technology development and design implementation may run the risk of proceeding with an ill‐defined project baseline.

In the climate of declining federal budgets and increased budget scrutiny, it is prudent to determine—as early as possible within a program schedule—the viability of technologies, and the ability of those technologies to support a specific project as well as the overall U.S. nuclear deterrent mission.

This paper describes the approach and tools used within the nuclear weapons programs for assessing the maturity of technologies and their readiness for insertion into the project design and execution schedule.
Synchronizing Systems Engineering and Implementation in Lean‐Agile Programs
Authors: Maione Robert , Wilson Mark A.
Published: August 2018

In traditional system development programs, high‐level statements of capability and mission needs are elaborated and functionally decomposed, and then systematically allocated to discrete program segments or subsystems. Functional decomposition continues to be a classic systems engineering technique to define and manage the development of large systems, but this approach can create issues in systems that are being developed using Lean‐Agile methods. Lean‐Agile developers typically adopt a “time box” perspective, where the goal is incremental delivery of system capability on a predictable schedule. In other words, Lean‐Agile developers may adopt a development rhythm with increments of rapidly evolving capability delivered every 10–12 weeks, while the SE team stays focused on the progress of the overall system as it was originally planned and defined. This divergence of both pace and perspective can lead to misunderstandings between systems engineers and developers or worse, disconnects between what the systems engineers think the developers are building and what developers are actually building.

Communication suffers when Lean‐Agile developers and program systems engineers operate in separate organizational “silos” instead of working together as a cohesive team. Day‐to‐day implementation decisions with potential impact to overall system capability can become buried within lower level engineering and development documents that are hard to synthesize to support timely program decisions. In our work with large programs employing Lean‐Agile development strategies, we discovered an approach that maintains systematic collaboration between developers and the SE team. In our approach, we explicitly measure and communicate incremental delivery of value using a new level of abstraction that we call Mission Value Threads (MVTs). MVTs directly link system requirements and their associated SE artifacts to Lean‐Agile development team backlogs and design documentation. This paper describes how to use MVTs to manage value delivery while fostering better collaboration between developers and systems engineers.
The Cynefin Framework and Technical Competencies: a New Guideline to Act in the Complexity
Authors: Fierro Davide , Putino Stefano , Tirone Lucio
Published: August 2018

The current socio‐economical context is affected by extremely challenging factors such as the macro‐economic crisis, the globalization of markets, the exponential growth in the complexity of systems, the continuous evolution of technologies and the criticality of requirements subject to rapid and sometimes uncontrollable evolution.

In such a competitive landscape the role of the future leaders gets essential. They shall be able, by means of a holistic, methodologically structured and flexible approach, to drive their programs through the implementation of the complex changes which are strategic to preserve the competitiveness. Such new leaders must be endowed with both strong technical skills, continuously trained in the key reference standards, and soft skills, useful for the strategic understanding of the evolutionary processes expressed by the markets and for the improvement of the complex relationships efficiency with the relevant stakeholders.

The development and implementation of optimized technical‐managerial solutions is therefore essential, vital for the “feasibility” and competitiveness of front‐running projects, and cannot succeed without a contextual analysis of the reference scenarios.

In this context the Cynefin Framework, an interpretative model of the different levels of the systems complexity, ranging from order to disorder, can provide a very effective support.

The goal of this paper is to develop a multi‐faceted and comprehensive vision of the problems in the various domains of complexity, “contextualizing” the most effective management approaches and “soft and hard” skills of the leader.

The paper benefits of the input received during various sessions of the second Cohort of the INCOSE Technical Leadership Institute, where precious insight and feedback has been collected, especially from the TLI coaches, Patrick Godfrey, Michael Pennotti and Don Gelosh.
Creating Decision Guidance for Applying Agile System Engineering
Authors: Lyells Ron , Angier Rock , Epps Bob
Published: August 2018

Systems teams, development projects, and organizations, who are involved in product development, are often faced with the question as to whether they should adapt agile systems practices into their programs and processes. In trying to answer this question these groups are almost immediately confronted with the problem of determining what is motivating the decision, where should agile principles be applied, and how much agility is necessary. There are several interrelated systems involved in this inquiry and the development of a proper understanding around these considerations is not a trivial exercise. A method of inquiry and decision making that is in itself agile and that can produce actionable results needs to guide the development of this understanding. The purpose of this paper is to present work accomplished to date on the definition, prototyping, and evaluation of a decision guidance system to help a development team or organization achieve a necessary understanding that can lead to useful actionable decisions regarding agile adoption.
A Framework for Testability Analysis from System Architecture Perspective
Authors: Efatmaneshnik Mahmoud , Ryan Michael J , Shoval Shraga
Published: August 2018

In this paper, we study the effects of system architecture on testability. We present a probabilistic model of testability that enables us to study the relationships between system architecture and testability. A Markov Chain model is used to obtain the quality of system after test as a function of its quality before test and the test quality. In particular, we focus on the costs and benefits associated with the modularization for testability. We show that choosing the appropriate testing architecture through careful modularization can greatly enhance efficiency and effectiveness of system testing. The model is based on repetitive testing that means the test will be repeated after a fail test outcome.
Using the Cognition Cockpit Platform for the Systems Engineering of a Local Health Care System in Cameroon
Authors: Kossmann Mario
Published: August 2018

All projects that are concerned with developing complex systems are potentially very challenging; yet charitable, i.e. not for profit, international development projects often have additional obstacles to overcome due to the geographical distance between the various stakeholders of the project; cultural, national and legal boundaries including multiple languages; uncertainty regarding the available budget and resources throughout the project life cycle, including the availability of needed volunteers; as well as a lack of the necessary infrastructure in terms of electricity, roads or telecommunications, if the focus of the project lies in developing countries. This is true not only for the Project Management activities of such projects but also for the related Systems Engineering activities.

Using the example of a charity project that is concerned with the development of a local health care system in a deprived region of Cameroon, this article illustrates and reports on the use of the ‘Cockpit’ platform of the US based Cognition Corporation to enable key Systems Engineering activities of the project. The aim of this paper is to share the experience made with the applied Systems Engineering approach and the supporting platform; and thereby offer relevant insights to practitioners who are involved in similar development projects.
SE Management is Not SE Core Competency: Time to Shift this Outdated, 60‐Year‐Old Paradigm
Authors: Wasson Charles
Published: August 2018

In the early 1950's the development of large, complex systems encountered two major challenges: (1) traditional Engineering methods were inadequate for coordinating and communicating designs and changes across multiple disciplines; and (2) projects were incurring unmanageable technical failures, cost overruns, and schedule slips. Exacerbating these challenges were growing conflicts between management and the engineers and scientists performing the engineering. These two challenges manifested themselves in the form of a “management gap,” which emerged due to management frustrations with engineers and scientists’ inability to articulate how the engineering process was performed, and (2) a “technology gap,” which emerged due to engineers and scientists’ frustrations with management's inability to understand how engineering was performed and the new technologies being implemented.

Central to these issues was the threat to the prevalent 1950's management paradigm of exercising authoritative control over subordinates by planning, organizing, staffing, directing, and controlling the tasks engineers and scientists performed. Corrective action solutions were urgently needed. Rather than solving the challenges, government as the acquirer of large, complex systems, decided to regain authoritative control over its contractors. As a result, the concept of Systems Management was introduced and mandated via a series of Systems, SE, and Engineering Management process standards.

Over the past 60+ years, the emerging field of Systems Engineering (SE), which originally focused on answering a key engineering question “Will the system work – i.e., ‘be fit for purpose’ when realized? (Ring, 2017) shifted to “did we follow our processes?” Projects corrected a “management” problem while neglecting the “engineering” question. As a result, projects continue to exhibit systemic performance issues. It is time to shift this outdated Systems Management paradigm and reestablish SE core competency as the “engine” for correcting SE contributions to project performance issues that seem so intractable.
Systems Interface Management with MBSE: from Theory to Modeling to Reality
Authors: Hause Matthew
Published: August 2018

Systems interoperate using interfaces. They exist between capabilities, organizations, people, systems, people and systems, systems and nature, systems of systems, and so forth. Interfaces are used to support both system to system communication as well as supporting the complete set of enterprise goals. Interfaces are where the most interesting things happen. And where most things go wrong. This paper addresses system interface‐management issues and the benefits of Model‐Based Systems Engineering (MBSE) approaches. An initial focus will be placed on interface information content that needs to be addressed at each level of system decomposition – from external stakeholders to system boundary to eventually, system component‐to‐component. The focus will then shift to interface management to model‐based and functional/logical design practice. It will also cover system interconnection and communications, how they change, operate and evolve over time to implement mission goals and to satisfy stakeholder needs. Finally it will look at physical systems and the connection to PLM/CAD domains.

Defining stakeholder goals and required capabilities

Interface definition with MBSE

Functional Architecture Interfaces

Logical Architecture Interfaces

Physical Architecture Interfaces

Allocation across cross cutting views

How behavior drives interfaces which drive behavior

Defining interaction requirements

Implementing effective and testable interface specifications

Traceability throughout the architecture

Service Oriented Architectures.
Modeling Cyber Threats with SysML
Authors: Curreri Matthew R. , Kam Ambrose , Hein Carl
Published: August 2018

Advanced Persistent Cyber Threats (APCT) jeopardize all seven layers in the Open System Interconnect (OSI). Scalable Modeled Based Engineering (MBE) methodologies can address APCT by leveraging industry standard SysML techniques by automating threat assessment for a multitude of operational scenarios. This paper provides a use case demonstrating how SysML can be combined with simulation to improve cyber defenses.
Design and prototype development of Dynamic Supply Chain Supporting (DSCS) system in Connected Smart Factory environment: focusing on architecture and data model
Authors: Park Jonghee , Jeon Byeongwoo , Hong Dae‐Geun , Suh Suk‐Hwan
Published: August 2018

SCM (Supply Chain Management) is responsible for the construction and operation of supply chain based on supply chain information. SCM implemented in modern enterprise information system needs to increase speed, accuracy, efficiency in accordance with customized production paradigm. We design SCM support system technology that can dynamically and efficiently operate existing static and fixed supply chain under Connected Smart Factory environment that supports real‐time information exchange between supply chain members according to Industry 4.0 concept. We also validate the technology using our demonstration test bed and prototype.
A Game‐Theoretical Framework for Coordination in Requirement‐Based Engineering Design
Authors: Yazdani Soodabeh , Huang Edward
Published: August 2018

Requirement‐based engineering design is a common practice that provides a definition of what is the desirable design solution. However, requirements define what constitutes the acceptable design from what is not, and provide a little guidance on the best design solution. Requirement‐based engineering with team coordination, on the other hand, allows design teams to exchange resources to best manage their resources. This may lead to the better design outcome. This paper investigates the benefits of coordination in requirement‐based engineering design. We apply game theory to formulate mathematical models of design problem with and without team coordination and demonstrate the mathematical framework on an illustrative example. The results indicate that we may not always get the system‐wide best performance in the requirement‐based engineering design while coordination among design teams can reduce the total cost of the system. Also, the numerical results capture the relation between team's effort level and system's cost coefficient.
A Systems Approach towards Developing a Diagnostic System for Complex Robots
Authors: Krishnan Rahul , Bhada Shamsnaz Virani
Published: August 2018

Present day robots are highly complex systems. Most robots perform tasks that are time‐critical in environments where human intervention may not be possible. When a failure occurs in such situations, diagnosing it can be a major challenge. To tackle this, a methodology to develop a diagnostic system using a systems approach is presented in this paper. The use of SysML diagrams as a tool to understand system behavior is highlighted. Finally, this methodology is used to build the diagnostic system of a complex humanoid robot.
Multinational validation of the American Joint Committee on Cancer 8th edition pancreatic cancer staging system in a pancreas head cancer cohort
Authors: Kwon Wooil , He Jin , Higuchi Ryota , Son Donghee , Lee Seung Yeoun , Kim Jaeri , Kim Hongbeom , Kim Sun‐Whe , Wolfgang Christopher L. , Cameron John L. , Yamamoto Masakazu , Jang Jin‐Young
Published: August 2018

Background

The aim of the present study was to compare the 7th and 8th editions of the American Joint Committee on Cancer (AJCC) staging system for pancreas head cancer and to validate the 8th edition using three multinational tertiary center data.

Methods

Data of 2,864 patients with pancreas head cancer were collected from Korea (571), Japan (824), and the USA (1,469). Survival analysis was performed to compare the 7th and 8th editions. Validation was performed by log‐rank tests and test for trend repeated 1,000 times with random sets.

Results

In the 7th edition, 4.1%, 3.1%, 18.6%, 67.5%, 3.6%, and 3.1% were stage IA, IB, IIA, IIB, III, and IV. In the 8th edition, 8.8%, 13.9%, 3.1%, 38.2%, 32.9%, and 3.1% were stage IA, IB, IIA, IIB, III, and IV, respectively. The change in T category downstaged 459 patients from IIA to the new IA and IB. The new N2 category upstaged 856 patients from the former IIB to III. The 7th edition reversely stratified IA and IB. The 8th edition corrected this mis‐stratification of the 7th edition, but lacked discriminatory power between IB and IIA (P = 0.271). Validation using the log‐rank showed that the 8th edition provided better discrimination in 6.387 test sets among 10 tests. The test for trend validated the 8th edition to stratify stages in correct order more often (7.815/10).

Conclusion

The 8th edition provides more even distribution with more powerful discrimination compared to the 7th edition.
Low‐level circulation and precipitation simulated by CMIP5 GCMS over southeastern South America
Authors: Barros Vicente R. , Doyle Moira E.
Published: August 2018

Global climate models (GCMs) have, in general, problems representing precipitation over southern southeastern South America (SSESA), namely southern Brazil, Uruguay and eastern Argentina. In this study, 18 models were selected from the Coupled Model Inter‐comparison Project Phase 5 to evaluate rainfall of the warm semester (October–March) when most of the rain takes place. Though GCMs reproduce the main features of the two main low‐level circulation variability modes over southeastern South America, east of the Andes, particularly the two flow patterns associated with the active and weak SACZ, most of them underestimate the northern flow that brings water vapour into SSESA, as well as the mean precipitation in this region. According to an index that stands for the northern flow towards SSESA, all models, except one, have lower northern flow into SSESA than the observed reanalysis field. In addition, this index has a significant correlation across GCMs with mean SSESA precipitation, indicating that lower northern flow into SSESA is generally associated with a greater underestimation in the model precipitation. Hence, it is concluded that the weaker northern flow into SSESA simulated by most GCMs is a cause of their simulated lower precipitation in this region.
Reply to comments on “Temperature‐extreme precipitation scaling: a two‐way causality?”
Authors: Lenderink Geert , Barbero Renaud , Westra Seth , Fowler Hayley J.
Published: August 2018

In recent years, numerous studies have investigated the relationship of extreme precipitation intensities with temperature derived from a binning method using present‐day weather data. The aim of this approach is that these dependencies, or so‐called apparent scaling rates, provide insights on how precipitation extremes could evolve in the future climate. In a recent paper, Bao et al. showed that there is a large discrepancy between the present‐day apparent scaling rates—showing a negative dependency of daily rainfall extremes on temperature for Darwin—and the climate change response showing a substantial increase in daily rainfall extremes. Their results provide compelling evidence that it may not be straightforward to predict the climate change response from the temperature scaling. We agree with this statement, but disagree with the physical explanation put forward in that study and think that moisture limitations are the most likely cause. Therefore, we advocate the use of dew point temperatures in scaling studies as a much more direct proxy of the absolute humidity of the air in which precipitation extremes develop, which we think is physically more consistent with the underlying mechanism causing the increase in precipitation extremes with global warming.
High molecular weight hyaluronan protects cartilage from degradation by inhibiting aggrecanase expression
Authors: Ohtsuki Takashi , Asano Keiichi , Inagaki Junko , Shinaoka Akira , Kumagishi‐Shinaoka Kanae , Cilek Mehmet Z. , Hatipoglu Omer F. , Oohashi Toshitaka , Nishida Keiichiro , Komatsubara Issei , Hirohata Satoshi
Published: August 2018

Hyaluronan (HA) is an extracellular matrix (ECM) component of articular cartilage and has been used to treat patients with osteoarthritis (OA). A disintegrin and metalloproteinases with thrombospondin motifs (ADAMTSs) play an important role in cartilage degradation in OA. We have previously reported that ADAMTS4 and ADAMTS9 were induced by cytokine stimulation. However, the effect of HA on the cytokine‐inducible ADAMTS9 has never been investigated. Moreover, it is unclear whether HA protects cartilage by suppressing aggrecan degradation. Here, we examined the effects of HA on ADAMTS expression in vitro and on cartilage degradation in vivo. ADAMTS9 expression was higher than that of the other aggrecanases (ADAMTS4 and 5) in human chondrocytes, chondrocytic cells, and rat cartilage. ADAMTS4 and 9 mRNA levels were upregulated in cytokine‐stimulated chondrocytes and chondrocytic cells. Pre‐incubation with HA significantly inhibited ADAMTS9 mRNA expression in cytokine‐stimulated cells. In a rat OA model, Adamts5 and 9 mRNA levels were transiently increased after surgery; intra‐articular HA injections attenuated the induction of Adamts5 and 9 mRNA. HA also blocked aggrecan cleavage by aggrecanase in OA rats in a molecular size‐dependent manner. These results demonstrate that HA attenuates induced aggrecanases expression in OA and thereby protects articular cartilage degradation by this enzyme. Our findings provide insight into the molecular basis for the beneficial effects of HA in OA. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:3247–3255, 2018.
Effects of non‐surgical periodontal therapy on clinical and immunological profile and oral colonization of Candida spp in HIV‐infected patients with chronic periodontitis
Authors: Nobre Átila V. V. , Pólvora Tábata L. S. , Silva Letícia R. M. , Teles Vanessa de O. , Villafuerte Kelly Vargas , da Motta Raphael J. G. , Fortes João H. P. , Silva Gilberto A. , Ranieri Ana Laura P. , de Macedo Leandro D. , Morejon Karen M. L. , da Fonseca Benedito A. L. , Tirapelli Camila , Saraiva Maria C. P. , Taba Mário , Lourenço Alan G. , Motta Ana Carolina F.
Published: August 2018

Background

After the introduction of antiretroviral therapy (ART), human immunodeficiency virus (HIV) infection has become a chronic controllable disease. For this reason, chronic conditions related to both HIV infection and senescence, such as chronic periodontitis (CP) need to be studied. This study investigated the impact of non‐surgical periodontal therapy (NSPT) on clinical and immunological features of CP, and on oral colonization by Candida spp. in HIV‐infected and non‐HIV‐infected individuals.

Methods

HIV‐infected (test group) and non‐HIV‐infected (control group) adults patients with CP were selected. Gingival bleeding index (GI), probing depth (PD), clinical attachment level (CAL), number of teeth, CD4+ T lymphocytes and viral load (only for HIV‐infected individuals), salivary cytokines (interleukin, [IL]‐6, IL‐8, and tumoral necrosis factor‐alpha [TNF‐α]), and oral Candida infection (colony forming units and species) were assessed at baseline, and 30 and 90 days after NSPT.

Results

Twenty‐two HIV‐infected patients and 20 non‐HIV‐infected patients were evaluated. Candida counts and salivary IL‐6, IL‐8, and TNF‐a levels were higher in the test group than in the control group. Both groups showed a decrease in oral Candida counts, GI, PD, IL‐6, and IL‐8 as well as gain in CAL at 30 and 90 days after NSPT. In addition, patients in the test group showed an increase of CD4+ T lymphocytes and a decrease of viral load.

Conclusion

NSPT had a beneficial impact on clinical and immunological parameters of CP, reduction of oral Candida counts, and improvement of HIV‐infection status.
Low‐Power Continuous‐Wave Second Harmonic Generation in Semiconductor Nanowires
Authors: Yuan Qingchen , Fang Liang , Yang He , Gan Xuetao , Khayrudinov Vladislav , Lipsanen Harri , Sun Zhipei , Zhao Jianlin
Published: August 2018

Semiconductor nanowires (NWs) are promising for realizing various on‐chip nonlinear optical devices, due to their nanoscale lateral confinement and strong light–matter interaction. However, high‐intensity pulsed pump lasers are typically needed to exploit their optical nonlinearity because light couples poorly with nanometric‐size wires. Here, microwatts continuous‐wave light pumped second harmonic generation (SHG) in AlGaAs NWs is demonstrated by integrating them with silicon planar photonic crystal cavities. Light–NW coupling is enhanced effectively by the extremely localized cavity mode at the subwavelength scale. Strong SHG is obtained even with a continuous‐wave laser excitation with a pump power down to W, and the cavity‐enhancement factor is estimated around 150. Additionally, in the integrated device, the NW's SHG is more than two orders of magnitude stronger than third harmonic generations in the silicon slab, though the NW only couples with less than 1% of the cavity mode. This significantly reduced power requirement of NW's nonlinear frequency conversion would promote NW‐based building blocks for nonlinear optics, especially in chip‐integrated coherent light sources, entangled photon pairs and signal processing devices.
Ethnic benign neutropenia: A phenomenon finds an explanation
Authors: Palmblad Jan , Höglund Petter
Published: August 2018

Ethnic benign neutropenia (ENP) is the most common form of neutropenia (NP) worldwide, if an absolute blood neutrophil count (ANC) of < 1.5 G/L is used as definition. In 2009, ENP was associated with a gene variation in the ACKR1/DARC gene, the same variation that also confers the Duffy‐null trait. In 2017, a novel mechanism for ENP was introduced, questioning if ENP is a true neutropenic state, when the body's total neutrophil count (TBNC) is concerned. Here, we summarize the current knowledge of ENP, asking (1) How well does the peripheral blood ANC predict the TBNC? (2) Can we improve methods for assessing TBNC? (3) Will estimates of TBNC predict infection propensity and reduce the need for further, costly workup?
Energy of reactions in atmospheric‐pressure plasma polymerization with inert carrier gas
Authors: Nisol Bernard , Watson Sean , Gagnon Hervé , Wertheimer Michael R.
Published: August 2018

It has come to the authors’ attention that Figure in the article by B. Nisol et al. (https://doi.org/10.1002/ppap.201500161, published in Plasma Process. Polym. 2016, 13, 557) displayed an erroneous result. An error occurred in the Matlab® code while carrying out the transfer of the energy measurement methodology to a larger DBD reactor. This erratum is published to correct this.
Designing Visible‐Light‐Driven Z‐scheme Catalyst 2D g‐C3N4/Bi2MoO6: Enhanced Photodegradation Activity of Organic Pollutants
Authors: Xia Kaixiang , Chen Hanxiang , Mao Mao , Chen Zhigang , Xu Fan , Yi Jianjian , Yu Yahui , She Xiaojie , Xu Hui , Li Huaming
Published: August 2018

Photocatalysis is a promising technology to solve the environment problems. Charge separation efficiency and oxidation capability are both vital factor determining the performance of photocatalysts. In this work, 2D g‐C3N4 is applied to modify Bi2MoO6 via an in situ hydrothermal method to design visible‐light‐driven Z‐scheme catalyst. The principle of this structure is to use the opposite surface charge of each component, maintaining the strong redox ability of photogenerated electrons and holes, preventing the recombination of photogenerated carrier effectively. As expected, the photodegradation performance of as‐prepared composites enhances dramatically compared with the pure Bi2MoO6. Afterward, kinetics and probable reaction mechanism are investigated and analyzed. It is proved that photogenerated carrier can be separated rapidly by tightly all‐solid‐state Z‐scheme junction. This work can provide a sight for finding controllable synthesis route of obtaining newly efficient visible‐light‐driven Z‐scheme photocatalysts.
Overlapping radiofrequency ablation planning and robot‐assisted needle insertion for large liver tumors
Authors: Liu Ping , Qin Jing , Duan Bin , Wang Qiong , Tan Xiaoyu , Zhao Baoliang , Jonnathan Peneyra Libao , Chui Chee‐Kong , Heng Pheng‐Ann
Published: August 2018

Background

We aimed at facilitating percutaneous radiofrequency ablation (RFA) for large tumors with accurate overlapping ablation planning and robot‐assisted needle insertion from a single incision port (SIP).

Methods

We developed a personalized and quantitative RFA planning method to obtain multiple needle overlapping ablation planning through a single incision. A robot with a remote center of motion mechanism was designed to perform needle insertions through a SIP according to the planning.

Results

Numerical and visual evaluation showed that the planning could yield nearly full coverage over large tumors and greatly reduce both ablation times and the ablations of normal tissues. Ex vivo and in vivo experiments showed that our robot‐assisted needle insertion system was capable of conducting the RFA procedure in large liver tumors from a SIP.

Conclusions

Robot‐assisted RFA needle insertions from a SIP makes RFA treatment for large tumors more minimally invasive, predictable, and repeatable.
Frequency offset insensitive demodulation algorithm for satellite‐based automatic identification system
Authors: Zhou Haosu , Lu Wenbin , Lv Zhenbin , Gu Hui , Liu Zhenfu
Published: August 2018

The frequency offset caused by the Doppler shift and the oscillators instability degrades the performance of satellite‐based demodulators for automatic identification system (AIS) signals unless proper synchronization algorithms are used. A noncoherent demodulation algorithm (NDA) based on cyclic redundancy check (CRC) error correction is proposed in this paper, which is able to tolerate large frequency offsets, thus avoiding the use of an explicit frequency synchronizer. To reduce the complexity, the number of CRC register states for error correction can be limited. Simulation results of the proposed algorithm are presented and compared with other demodulation algorithms in the literature in terms of bit error rate (BER) and packet error rate (PER).
Understanding the Correlation of Crystal Atoms with Photochemistry Property: Zn5(OH)6(CO3)2vs. ZnCO3
Authors: Liu Zhe , Teng Fei
Published: August 2018

In this work, Zn5(OH)6(CO3)2 nanosheets are prepared by a simple hydrothermal method, and ZnCO3 are also prepared to compare. It is found that compared with ZnCO3, hydroxyl anion greatly changes energy band structure and oxidation potential of valence band, and improves charge separation efficiency and rates of Zn5(OH)6(CO3)2. The time‐resolved photoluminescence (PL) results show that the average lifetime (τ) of carriers is 1.485 ns for Zn5(OH)6(CO3)2, while 0.380 ns for ZnCO3, illustrating a greatly low carrier recombination rate of Zn5(OH)6(CO3)2; and Zn5(OH)6(CO3)2 has a 20 times photocurrent higher than ZnCO3. Besides, Zn5(OH)6(CO3)2 has a greatly higher oxidation potential (5.05 V) than ZnCO3 (3.17 V), suggesting a high oxidizing ability of Zn5(OH)6(CO3)2. Under ultraviolet light irradiation (λ≤400 nm), 92% of MB can be degraded by Zn5(OH)6(CO3)2 after 80 min, which is 2.31 times as high as that of ZnCO3, although Zn5(OH)6(CO3)2 has a lower BET area (5.8 m2g−1) than ZnCO3 (7.7 m2g−1). This work favors to insight into the correlation of crystal atoms with photochemistry property for a photocatalyst.
Parkia speciosa as Reduction Agent in Green Synthesis Silver Nanoparticles
Authors: Yusof Khairul Nazri , Alias Siti Salwa , Harun Zawati , Basri Hatijah , Azhar Faiz Hafeez
Published: August 2018

Synthesis of nanoparticles based on plant extract as reduction agent has been discovered extensively due to its environmental friendly approach. In this work, a facile silver nanoparticles is synthesized via incorporation of silver nitrate aqueous solution with Parkia speciosa leaves extract. Centrifugation is introduces to improve the characteristics of nanoparticles. Chemical interactions have identified –OH stretching vibration, C=O and C=C, proving the presence of phenolic, terpenoid and flavonoid capped on silver nanoparticles. The TEM result demonstrates the silver nanoparticles had consistence spherical nanoparticles shape with average particles size (59.96 nm) in accordance with FESEM analysis. The structural analysis by XRD shows the nanoparticles had high degree of crystallinity (97%) and crystallite size (17.95 nm). The optical analysis by UV‐Vis reveals that the nanoparticle produces brown colour solution with high absorption band (465 nm). This proves that Parkia speciosa extract has potential as reduction agent in synthesis of silver nanoparticles.
Two New Cerioptins (A‐B) from the Mangrove Ceriops tagal
Authors: Sura Madhu Babu , Dangeti Nalini , Ponnapalli Mangala Gowri
Published: August 2018

Two novel compounds (1‐2), cerioptins A−B, along with seven known compounds were isolated from the mangrove, Ceriops tagal. These new compounds were characterized as a rare ethyl‐[(2‐allyl‐2‐chloromethyl)‐2H‐1‐benzopyran]‐3‐carboxylate (1) and a novel tetraterpenoid congener of heterodimeric diterpenoid, pimara‐11‐enol‐(16→2′)‐dolabra‐1,4(18),15‐triene (2) by extensive modern spectroscopic 2D NMR [COSY (correlation spectroscopy), NOESY (Nuclear Overhauser Effect Spectroscopy), HSQC (heteronuclear single‐quantum correlation), HMBC (heteronuclear multiple bond correlation)], IR (infrared) and mass data analysis. The naturally occurring new heterodimeric diterpene is derived from two new diterpenes as pimara‐11‐enol and dolabra‐1,4(18),15‐triene.
Polyprodrug Antimicrobials: Remarkable Membrane Damage and Concurrent Drug Release to Combat Antibiotic Resistance of Methicillin‐Resistant Staphylococcus aureus
Authors: Cao Bing , Xiao Fengfeng , Xing Da , Hu Xianglong
Published: August 2018

The increased threat of antibiotic resistance has created an urgent need for new strategies. Herein, polyprodrug antimicrobials are proposed to mimic antimicrobial peptides appended with a concurrent drug release property, exhibiting broad‐spectrum antibacterial activity and especially high potency to inhibit methicillin‐resistant Staphylococcus aureus (MRSA) without inducing resistance. Two series of polyprodrug antimicrobials are fabricated by facile polymerization of triclosan prodrug monomer (TMA) and subsequent quaternization of hydrophilic poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA), affording PDMAEMA‐b‐PTMA and PQDMA‐b‐PTMA, respectively. Optimized samples with proper hydrophobic ratio are screened out, which exhibit remarkable bacterial inhibition and low hemolysis toward red blood cells. Furthermore, synergistic antibacterial mechanisms contribute to the bacteria killing, including serious membrane damage, increased out‐diffusion of cytosolic milieu across the membrane, and intracellular reductive milieu‐mediated triclosan release. No detectable resistance is observed for polyprodrug antimicrobials against MRSA, which is demonstrated to be better than commercial triclosan and vancomycin against in vivo MRSA‐infected burn models and a promising approach to the hurdle of antibiotic resistance in biomedicine.
Direct‐Write Formation and Dissolution of Silver Nanofilaments in Ionic Liquid‐Polymer Electrolyte Composites
Authors: Chao Zhongmou , Radka Brian P. , Xu Ke , Crouch Garrison M. , Han Donghoon , Go David B. , Bohn Paul W. , Fullerton‐Shirey Susan K.
Published: August 2018

Materials with reconfigurable optical properties are candidates for applications such as optical cloaking and wearable sensors. One approach to fabricate these materials is to use external fields to form and dissolve nanoscale conductive channels in well‐defined locations within a polymer. In this study, conductive atomic force microscopy is used to electrochemically form and dissolve nanoscale conductive filaments at spatially distinct points in a polyethylene glycol diacrylate (PEGDA)‐based electrolyte blended with varying amounts of ionic liquid (IL) and silver salt. The fastest filament formation and dissolution times are detected in a PEGDA/IL composite that has the largest modulus (several GPa) and the highest polymer crystal fraction. This is unexpected because filament formation and dissolution events are controlled by ion transport, which is typically faster within amorphous regions where polymer mobility is high. Filament kinetics in primarily amorphous and crystalline regions are measured, and two different mechanisms are observed. The formation time distributions show a power‐law dependence in the crystalline regions, attributable to hopping‐based ion transport, while amorphous regions show a normal distribution. The results indicate that the timescale of filament formation/dissolution is determined by local structure, and suggest that structure could be used to tune the optical properties of the film.
A New Way to Promote Molecular Drug Release during Medical Treatment: A Polyelectrolyte Matrix on a Piezoelectric–Dielectric Energy Conversion Substrate
Authors: Zhang Yi , An Qi , Tong Wangshu , Li Haitao , Ma Zequn , Zhou Yan , Huang Tao , Zhang Yihe
Published: August 2018

Enhanced drug releases in a timely manner during urgent medical treatments would significantly enhance the prognosis of patients. Inspired by the facilitated molecular transports by the potentials, an enhanced drug release strategy driven by mechanical disturbances that widely exist in medical treatment processes is proposed. This strategy is enabled by a functional material comprised of multilayers of dendrimers as the drug reservoir, which are built on a piezoelectric–dielectric flexible film with reduced graphene oxide fillers. The generated voltages are higher and last longer than that in regular piezoelectric films. Photochemical crosslinking leads to a stable drug matrix which is even sustained in electric fields and high ionic strengths. The device enhances releases of positively, negatively, and zwitterionically charged molecules in response to mechanical stimuli and supports high cell viabilities. An illustrative application is demonstrated by preparing the material on the surface of a gastric lavage tube. The results show that the release of antiemetic drug increased by 200% within 60 min in response to forces mimicking human swallowing. This study contributes an integrative material that can realize electrically triggered releases that are previously only realized using complicated electrochemical setups. It is believed that this material can facilitate medicine applications in various emergent situations.
Fostering Autonomous Motivation and Early Literacy Skills
Authors: Erickson Joy Dangora , Wharton‐McDonald Ruth
Published: August 2018

The authors emphasize the importance of cultivating autonomous motivation for literacy in early childhood by supporting students’ basic psychological needs for autonomy, competence, and relatedness while building foundational skills. Additionally, the authors highlight four key findings specific to early childhood (pre‐K–2) literacy development: the power of teaching letters and associated phonemes in tandem, the impact of oral language on comprehension, the role of print concepts in learning to read, and the influence of early writing on reading. Sample activities, adapted from preexisting promising practices to incorporate opportunities for addressing students’ basic psychological needs, accompany each finding. Finally, the authors make a sincere appeal for additional research, including educator action research specific to early childhood literacy motivation.
New Aspects with Regard to Silanide Chemistry in Particular Formation and Structure of the First Disilyl Sodate [K(Me2SiO)7][(tBu3Si)2MeSi‐Na‐SiMe(SitBu3)2]
Authors: Sänger Inge , Gärtner Michael , Bolte Michael , Wagner Matthias , Lerner Hans‐Wolfram
Published: August 2018

:The silanide Na[SiMe(SitBu3)2] was prepared by three step synthesis: In a first step, two equivalents of Na[SitBu3] were reacted with Cl2MeSi‐H to give (tBu3Si)2MeSi–H. In a second step the silane (tBu3Si)2MeSi–H was brominated. Thereby we could isolate single crystals of (tBu3Si)2MeSi–Br (monoclinic, space group C2/c), which were suitable for X‐ray diffraction. Subsequent reaction of (tBu3Si)2MeSi–Br with sodium yielded the silanide Na[SiMe(SitBu3)2] in heptane at room temperature. X‐ray quality crystals of the donor‐free silanide Na[SiMe(SitBu3)2] (monoclinic, space group P21/c) were grown from heptane at room temperature. The 29Si NMR spectrum of a 1:1 solution of K[OtBu] and Na[SiMe(SitBu3)2] in thf revealed resonances, which could not be attributed either to Na[SiMe(SitBu3)2] nor K[SiMe(SitBu3)2]. Single crystals of [K(Me2SiO)7][(tBu3Si)2MeSi–Na–SiMe(SitBu3)2] were grown from an equimolar mixture of K[OtBu] and Na[SiMe(SitBu3)2] in heptane over a period of 4 weeks at room temperature. The potassium disilylsodate was characterized by X‐ray crystallography (trigonal, space group P3121).
[Fe{(η5‐C5H4)N(SiMe2tBu)}2Al]2: A Stable Redox‐Functionalized Dialumane(4)
Authors: Correia Bicho Bruno A. , Bruhn Clemens , Guthardt Robin , Weyer Nadine , Siemeling Ulrich
Published: August 2018

The diaminoferrocene derivatives [Fe{(η5‐C5H4)NHR}2] (1H2, a: R = SiMe2tBu, b: R = CMe2tBu, c: R = C6H3‐2,6‐iPr2) were converted into the lithium amides 1aLi2 – 1cLi2 by treatment with nBuLi. The reaction of these amides with AlI3 furnished 1aAlI – 1cAlI. The reduction of 1aAlI with KC8 afforded 1aAl–Al1a, which is a new stable dialumane(4) with exclusively tricoordinate Al atoms and only the second example so far of a tetraamino‐substituted compound of this kind. 1bH2, 1cH2, 1aLi2, [1c{Li(THF)3}2], [1aAlI(OEt2)], 1cAlI, 1aAl–Al1a·½Et2O and 1aAl–Al1a·½C7H8 were structurally characterized by single‐crystal X‐ray diffraction.
The Curious Case of a Phenylated Guanidinoquinoline Ligand: Synthesis, Complexes and ATRP Properties of DMEG6phqu
Authors: Rösener Thomas , Kröckert Konstantin , Hoffmann Alexander , Herres‐Pawlis Sonja
Published: August 2018

In previous studies, copper halide complexes of the guanidinoquinoline (GUAqu) ligands 1,3‐dimethyl‐N‐(quinolin‐8‐yl)‐imidazolidin‐2‐imine (DMEGqu) and 1,1,3,3‐tetramethyl‐2‐(quinolin‐8‐yl)‐guanidine (TMGqu) were successfully implemented in atom transfer radical polymerization (ATRP) and could be further enhanced by introduction of alkyl substituents at C6 position of the quinoline backbone. Herein, the ligand DMEG6phqu is presented. The quinoline backbone of this ligand is equipped with a phenyl substituent at C6 position. This study deals with the influence of the phenyl substituent on solubility and molecular structural properties of DMEG6phqu CuI and CuII bromide complexes. In contrast to previously reported systems, the CuIBr complex of DMEG6phqu crystallizes as a trigonal coordinated monochelate complex. However, NMR and UV/Vis spectroscopic experiments indicate that DMEG6phqu forms a bischelate species in solution. The influence of the substituent on the complex redox potential and ATRP equilibrium constant KATRP is discussed. In contrast to expectations, it turned out that copper halide complexes of DMEG6phqu are completely insoluble in the apolar monomer styrene. However, ATRP kinetics were performed in solution and the results are compared to previous studies.
Exponentially light dark matter from coannihilation
Authors: D’Agnolo Raffaele Tito , Mondino Cristina , Ruderman Joshua T. , Wang Po-Jen
Published: August 2018

Abstract

Dark matter may be a thermal relic whose abundance is set by mutual annihilations among multiple species. Traditionally, this coannihilation scenario has been applied to weak scale dark matter that is highly degenerate with other states. We show that coannihilation among states with split masses points to dark matter that is exponentially lighter than the weak scale, down to the keV scale. We highlight the regime where dark matter does not participate in the annihilations that dilute its number density. In this “sterile coannihilation” limit, the dark matter relic density is independent of its couplings, implying a broad parameter space of thermal relic targets for future experiments. Light dark matter from coannihilation evades stringent bounds from the cosmic microwave background, but will be tested by future direct detection, fixed target, and long-lived particle experiments.