bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent Progress in Asymmetric Ion‐Pairing Catalysis with Ammonium Salts
Authors: Qian Deyun , Sun Jianwei 
Published: October 2018

AbstractQuaternary ammonium salts play an important role in asymmetric catalysis. In this Minireview, how asymmetric ion‐pairing catalysis with ammonium ions has been utilized in organic synthesis is explained, particularly in the design of novel catalytic cycles. This includes the use of chiral ammonium‐based catalysts for the construction of challenging stereogenic centers. Ammonium‐derived electrophilic reagents, typically formed in situ and in the context of phase‐transfer catalysis (PTC), have also been utilized in asymmetric bond‐forming reactions. Furthermore, ammonium salts have been employed as substrates in several stereocontrolled C−N bond cleavage processes, leading to enantioenriched products by using novel asymmetric induction modes. In addition, merging ammonium ion‐pairing catalysis with other catalytic approaches has also emerged as a new platform for achieving previously less straightforward reactions, thereby allowing new synthetic applications.
Spatially‐Resolved Multiple Metallopolymer Surfaces by Photolithography
Authors: Müller Rouven , Feuerstein Thomas J. , Trouillet Vanessa , Bestgen Sebastian , Roesky Peter W. , Barner‐Kowollik Christopher 
Published: October 2018

AbstractA tetrazole‐based photoligation protocol for the spatially‐resolved encoding of various defined metallopolymers onto solid surfaces is introduced. By using this approach, fabrication of bi‐ and trifunctional metallopolymer surfaces with different metal combinations were achieved. Specifically, α‐ω‐functional copolymers containing bipyridine as well as triphenylphosphine ligands were synthesized through reversible addition‐fragmentation chain transfer (RAFT) polymerization, and subsequently metal loaded to afford metallopolymers of the widely‐used metals gold, palladium, and platinum. Spatially‐resolved surface attachment was achieved by means of a nitrile imine‐mediated tetrazole‐ene cycloaddition (NITEC) based photoligation protocol, exploiting tethered tetrazoles and metallopolymers equipped with a maleimide chain terminus. Metallopolymer coated surfaces with three different metals were prepared and characterized by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and spatially‐resolved X‐ray photoelectron spectroscopy (XPS) mapping, supporting the preserved chemical composition of the surface‐bound metallopolymers. The established photochemical technology platform for arbitrary spatially‐resolved metallopolymer surface designs enables the patterning of multiple metallopolymers onto solid substrates. This allows for the assembly of designer metallopolymer substrates.
Asymmetric Carboxycyanation of Aldehydes by Cooperative AlF/Onium Salt Catalysts: from Cyanoformate to KCN as Cyanide Source
Authors: Brodbeck Daniel , Álvarez‐Barcia Sonia , Meisner Jan , Broghammer Florian , Klepp Julian , Garnier Delphine , Frey Wolfgang , Kästner Johannes , Peters René 
Published: October 2018

AbstractAsymmetric 1,2‐additions of cyanide yield enantioenriched cyanohydrins as versatile chiral building blocks. Next to HCN, volatile organic cyanide sources are usually used. Among them, cyanoformates are more attractive on technical scale than TMSCN for cost reasons, but catalytic productivity is usually lower. Here, the development of a new strategy for cyanations is described, in which this activity disadvantage is overcome. A Lewis acidic Al center cooperates with an aprotic onium moiety within a remarkably robust bifunctional Al–F–salen complex. This allowed for unprecedented turnover numbers of up to 104. DFT studies suggest an unexpected unique trimolecular pathway in which the ammonium bound cyanide attacks the aldehyde, which itself is activated by the carbonyl group of the cyanoformate binding to the Al center. In addition, a novel practical carboxycyanation method was developed that makes use of KCN as the sole cyanide source. The use of a pyrocarbonate as carboxylating reagent provided the best results.
Vapoluminescent Behavior and the Single‐Crystal‐to‐Single‐Crystal Transformations of Chloroform Solvates of [Au2(μ‐1,2‐bis(diphenylarsino)ethane)2](AsF6)2
Authors: England Kellie R. , Lim Sang Ho , Luong Lucy M. C. , Olmstead Marilyn M. , Balch Alan L. 
Published: October 2018

AbstractThe mono‐ and di‐chloroform solvates of [Au2(μ‐1,2‐bis(diphenylarsino)ethane)2](AsF6)2 undergo single‐crystal‐to‐single‐crystal transformations that result in gain (over 12 hours) or slow loss (over five years) of only one chloroform molecule. The change in solvation results in changes in the structure and luminescence of the digold cation. The cation consists of a pair of slightly bent As‐Au‐As units that are connected through the two bridging dpae ligands and by aurophilic interactions with Au⋅⋅⋅Au contacts of 3.05152(15) Å in the disolvate or 2.9570(5) Å in the monosolvate.
Synthetic Studies on Spirolides A and B: Formation of the Upper Carbon Framework Based on a Lewis Acid Template‐Catalyzed Diels–Alder Reaction
Authors: Ishihara Jun , Usui Fuma , Kurose Tomohiro , Baba Tomohiro , Kawaguchi Yasunori , Watanabe Yuki , Hatakeyama Susumi 
Published: October 2018

AbstractThe upper fragment of spirolides A and B, which are marine phycotoxins that exhibit strong antagonistic activities on nicotinic acetylcholine receptors, was constructed. The functionalized cyclohexene in spirolides was stereoselectively synthesized from the bicyclic lactone, which could be readily accessed by the Lewis acid template‐catalyzed asymmetric Diels–Alder reaction of the pentadienol and methyl acrylate.
Metal‐Free Regioselective Chloroazidation of Internal Alkynes
Authors: Huang Bin , Liffert Raphael , Linden Anthony , Gademann Karl 
Published: October 2018

AbstractA metal‐free, room temperature protocol for the regioselective chloroazidation of internal alkynes is disclosed. The reactions of internal alkynes with trimethylsilyl azide (TMSN3) in the presence of 1,3‐dichloro‐5,5‐dimethylhydantoin (DCDMH) afforded the corresponding chloroazidoalkenes in good yields. This reaction has good functional group tolerance and is operationally simple.
Economic assessment of patient navigation to colonoscopy‐based colorectal cancer screening in the real‐world setting at the University of Chicago Medical Center
Authors: Kim Karen E. , Randal Fornessa , Johnson Matt , Quinn Michael , Maene Chieko , Hoover Sonja , Richmond‐Reese Valerie , K. L. Tangka Florence , Joseph Djenaba A. , Subramanian Sujha 
Published: October 2018

BackgroundThis report details the cost effectiveness of a non‐nurse patient navigation (PN) program that was implemented at the University of Chicago Medical Center to increase colonoscopy‐based colorectal cancer (CRC) screening.MethodsThe authors investigated the impact of the PN intervention by collecting process measures. Individuals who received navigation were compared with a historic cohort of non‐navigated patients. In addition, a previously validated data‐collection instrument was tailored and used to collect all costs related to developing, implementing, and administering the program; and the incremental cost per patient successfully navigated (the cost of the intervention divided by the change in the number who complete screening) was calculated.ResultsThe screening colonoscopy completion rate was 85.1% among those who were selected to receive PN compared with 74.3% when no navigation was implemented. With navigation, the proportion of no‐shows was 8.2% compared with 15.4% of a historic cohort of non‐navigated patients. Because the perceived risk of noncompletion was greater among those who received PN (previous no‐show or cancellation, poor bowel preparation) than that in the historic cohort, a scenario analysis was performed. Assuming no‐show rates between 0% and 50% and using a navigated rate of 85%, the total incremental program cost per patient successfully navigated ranged from $148 to $359, whereas the incremental intervention‐only implementation cost ranged from $88 to $215.ConclusionsThe current findings indicate that non‐nurse PN can increase colonoscopy completion, and this can be achieved at a minimal incremental cost for an insured population at an urban academic medical center.
Colorectal cancer screening interventions in 2 health care systems serving disadvantaged populations: Screening uptake and cost‐effectiveness
Authors: Lara Christen L. , Means Kelly L. , Morwood Krystal D. , Lighthall Westley R. , Hoover Sonja , Tangka Florence K.L. , French Cynthia , Gayle Krystal D. , DeGroff Amy , Subramanian Sujha 
Published: October 2018

AbstractBackgroundThe objectives of the current study were to assess changes in colorectal cancer (CRC) screening uptake and the cost‐effectiveness of implementing multiple evidence‐based interventions (EBIs). EBIs were implemented at 2 federally qualified health centers that participated in the Colorado Department of Public Health and Environment’s Clinic Quality Improvement for Population Health initiative.MethodsInterventions included patient and provider reminder systems (health system 1), provider assessment and feedback (health systems 1 and 2), and numerous support activities (health systems 1 and 2). The authors evaluated health system 1 from July 2013 to June 2015 and health system 2 from July 2014 to June 2017. Evaluation measures included annual CRC screening uptake, EBIs implemented, funds received and expended by each health system to implement EBIs, and intervention costs to the Colorado Department of Public Health and Environment and health systems.ResultsCRC screening uptake increased by 18 percentage points in health system 1 and 10 percentage points in health system 2. The improvements in CRC screening uptake, not including the cost of the screening tests, were obtained at an added cost ranging from $24 to $29 per person screened.ConclusionsIn both health systems, the multicomponent interventions implemented likely resulted in improvements in CRC screening. The results suggest that significant increases in CRC screening uptake can be achieved in federally qualified health centers when appropriate technical support and health system commitment are present. The cost estimates of the multicomponent interventions suggest that these interventions and support activities can be implemented in a cost‐effective manner.
A robust recommended system based on attack detection
Authors: Yang Qin 
Published: October 2018

SummaryIn the increasingly fierce competition in e‐commerce sites, the recommendation system has brought great benefits to the site, but some unscrupulous businesses use the recommended system algorithm loopholes, the use of bulk injection of some fake users, and the ratings of these users with the normal user's rating. Therefore, when calculating user similarity, it is easy to enter the user's neighborhood circle, because the false user takes a high score (“push attack”) or a low score (“null attack”) on the target project. The recommendation scores will be biased, and it is important to detect these false users for the recommendation system and maintain a good e‐commerce competitive environment. In this paper, we propose a recommendation algorithm that divides user‐generated ratings into normal ratings and non‐generic ratings and refine and use state information to minimize the impact of spurious malicious users. Our algorithm first ensures that the recommender system is stable against the three main attack modes (random attack, average attack, power flow attack). Through the analysis of the real data, we verify the performance of the proposed scheme and compare our algorithm with the existing one.
A PCA and Mahalanobis distance‐based detection method for logical hardware Trojan
Authors: Huang Jiaoying , Yang Daming , Gao Cheng , Fu Chengcheng 
Published: October 2018

SummaryDue to wide application of FPGA devices, which are easy to be attacked by HTs, it has been risen up more concern on chip security. In order to ensure the efficiency of detection, side‐channel analysis is used to detect HTs. However, existing methods for HT detection cannot detect the LHTs with the small size, which takes up lower than 1% area of the whole chip, considering that signal of LHTs is drowned in process deviations. To complete the side‐channel analysis for LHT, we proposed an algorithm that combines PCA and Mahalanobis distance to improve the accuracy of LHTs detection. In addition, performed on FPGA of Xilinx, a sample of LHTs was designed and verified, which took up nearly 0.1% area of the whole chip. The influence of process deviation on the power consumption of FPGA was simulated by Hspice. A set of power‐frequency data of golden FPGA was generated by Matlab as panel data, which was considering the influence. Another two sets of FPGA with and without LHT were generated to test the accuracy of the proposed method. For LHT and golden FPGA, the detection accuracy of proposed method is 99% and 87%, respectively.
Effect of hole on sound absorption coefficient of micro‐perforated panels investigated by Melling computing
Authors: Wang Kun , Wang Wei , Yan Xiong 
Published: October 2018

SummaryMicroperforated board is one of the important ways to absorb noise. However, the mechanism is still not well understood of the interaction between micropores, and the influence of the distance between the micropores on the sound absorption performance of microperforated plates is still not clarified. Professor Merlin introduced the influence of micropore interaction on the sound absorption performance of microperforated plates. Based on Maa and Melling theory, this paper proposed an absorption coefficient that considers the effect of perforation interactions. In addition, the formula was used to calculate the absorption coefficient and the resonance frequency and, subsequently, was tested by the conducted experiments. The results show that the structure parameters of the micro‐perforated panel affect its absorption coefficient, and the model can search the absorption coefficient more efficiently, with the calculated result close to the experimental value.
Secured and anonymous data transmission in Manet environment using zone‐based intrusion detection system
Authors: Soms Nisha , Malathi P. 
Published: October 2018

SummaryZone‐based intrusion detection is a supporting protection mechanism for mobile adhoc environment consisting of large volume of distributed number of nodes. With the presence of malicious nodes, security will be violated, which is focused in proposed research by introducing Secured and Anonymous Zone‐Based Intrusion Detection System (SAZIDS). Here, anonymous rule sharing is guaranteed by introducing the Anonymous Location‐Aided Routing in MANET in which group signatures would be generated by all zone members based on group public key provided by the intra zone leader. Thus, the exact location of zone members cannot be revealed. To ensure the secured rule sharing, Enhanced Adaptive ACKnowledgment is utilized, which would ensure the presence of malicious nodes. This is done at the time of rule sharing by the intra zone leaders. After secured sharing of rule set, in order to optimize the memory storage, in this work, rule set aggregation is performed, which would merge the rules, thus resolving the bandwidth and associated memory issues. The overall evaluation of SAZIDS is performed in the NS2 simulation environment, which proves secured and reliable transmission of data without the involvement of malicious activities.
Energy efficient low‐power full‐adder by 65 nm CMOS technology in ALU
Authors: N Suresh Kumar , K Paramasivam 
Published: October 2018

SummaryThe arrangement of energy efficient low‐power full adder has vital role in VLSI systems. In this paper Energy Efficient Low‐power 9T full‐adder is proposed. Its functioning basis of Power Delay Product (PDP), Delay, power and area is distinguished in accordance with that current 1 bit full‐adder simulated by utilizing various Complementary MOS logic designs. Output provides an average minimization of 99.28% in power usage, 67.87% in area, 99.89% in delay, and 99.99% in Power‐Delay Product (PDP) distinguished to the traditional 28 Transistors CMOS logic. The ALU design has been implemented using 9T full adder. These logic gates are analysis at 65 nm technology of CMOS by utilizing Schematic Editor Tool.
An improved prediction algorithm of seamless tubing corrosion based on an extension neural network
Authors: Wang Ti‐chun , Tong Chang‐sheng , Yao Sheng‐hu 
Published: October 2018

SummaryIn view of the fact that the corrosiveness of seamless steel tubes under actual conditions was difficult to predict, the main influencing factors of seamless oil tube corrosion under actual conditions were analyzed, and a model for predicting the corrosion of seamless oil tubes was constructed. The algorithm of the extension neural network was introduced. The Python language was used to implement the extensible neural network algorithm, and the influencing factors of steel tube corrosion were trained. The extension neural network was simulated and verified, and finally, the system is implemented by the mobile APP.
Study of single event transient induced by heavy‐ion in NMOS transistor and CMOS inverter
Authors: Gao Cheng , Zhang Rui , Huang Jiaoying , Fu Chengcheng 
Published: October 2018

SummarySET has become the main concern of radiation effect researchers as technology scales down and increasing sensitivity of modern integrated circuits. Transient response induced by heavy‐ion, especially the impact of parasitic bipolar amplification in both the NMOS transistor and the CMOS inverter, is investigated in this paper. The bipolar effect of the bulk NMOS transistor has been studied through transient current measurements by using 3‐D simulation. The simulation of a 3‐D structure has confirmed the enhancement effect due to the bipolar‐like structure inherent to the NMOS transistor. With regard to the CMOS inverter, waveforms of transient voltage pulse are fully measured via 2‐D mixed‐mode simulation. In addition, the impact of LET on transient voltage pulse amplitude and width is analyzed; also, the effect of load capacitance on voltage pulse amplitude is discussed as well. The 2‐D mixed‐mode simulation results indicate that SET pulse amplitude increases with the value of LET due to enhancement of drift, while SET pulse width increases with the LET for the reason of more significant parasitic bipolar amplification effect. In addition, SET pulse amplitude increases monotonically with the load capacitance. This paper further investigates the bipolar amplification mechanism in bulk MOSFET and analyzes the variation of transient voltage pulse in different conditions in deep submicron device.
The dynamics behaviors of Chay neuron model under different parameters
Authors: Kaijun Wu , Chao Yu , Dicong Wang 
Published: October 2018

SummaryBased on C‐language and Matlab, this paper numerically simulates the dynamic behaviors of Chay neuron model under different parameters using the bifurcation diagram of Inter‐spike interval (ISI), time response graph, and phase diagram. The results show that the period‐adding, period‐doubling, and chaos phenomena of Chay neuron model were observed intuitively in the bifurcation diagram of ISI controlled by different parameters, and these phenomena were also found in the corresponding time response graph and phase diagram. These results provide a basis for further understanding the physiological characteristics of Chay neuron model.
Secure cloud‐based e‐learning system with access control and group key mechanism
Authors: Kanimozhi S. , Kannan A. , Suganya Devi K. , Selvamani K 
Published: October 2018

SummaryThere are lot of research works carried out in the field of Information Technology (IT), which have more impact on the education throughout the world. The main contribution from IT in today's education world is e‐learning. There are several institutions implemented the mechanism and several technologies of e‐learning in different countries. E‐learning provides more flexibility in education. Although there are several organizations and institutions had come up with the e‐learning system, the cost of investment involved for the infrastructure setup is much higher for e‐learning applications. Cloud Computing is one of the important technology, which provides different services, which plays a vital role in the education domain and e‐learning mechanism. In addition, the security factor in sharing the content is also much important nowadays as the content is shared among different countries with multiple source environments. In this paper, cloud‐based e‐learning is implemented using access control mechanism, which prevents the cloud resources from illegal user access. The key management schemes combined with access control technique is discussed for secure content sharing and to protect the e‐learning environment. The traditional e‐learning mechanism is compared with the cloud e‐learning for the better understanding of the cloud usage and advantages. Findings indicate that cloud‐based e‐learning utilizes cloud services in a secure way and also more flexible and scalable in accessing the e‐learning content.
An efficient RSA cryptosystem by applying cuckoo search optimization algorithm
Authors: Raja shree S. , Chilambu Chelvan A. , Rajesh M. 
Published: October 2018

SummaryCloud computing is a promising technology that provides ubiquitous and on‐demand network access to a shared pool of configurable computing devices. However, the security is a major challenge in cloud environment due to the data sharing via the internet and data stored in the cloud. In cloud computing, there are various security issues such as confidentiality, integrity, and authentication. Among these issues, data integrity play a significant role in the cloud computing and various techniques were proposed to secure the data stored in the cloud. In this paper, an efficient RSA algorithm is proposed to overcome the data integrity problem in the cloud by applying Cuckoo Search Optimization (CSA) algorithm. In this, the encryption of data and secret key generation is done using RSA cryptosystem for securing data from unauthorized users'. In order to avoid the brutal force attack, CSA algorithm is used to optimize the encryption of the key. The simulation results demonstrate that the proposed algorithm performs faster than the conventional RSA and Data Encryption Standard (DES) algorithms. Moreover, the proposed algorithm provides better throughput while increasing the private key length of the algorithm.
Design and implementation of intelligent energy control for tariff management using multi‐agent system in smart/micro grid
Authors: Satheesh Kumar G.S. , Nagarajan C. 
Published: October 2018

SummaryIncorporation of the renewable resources (RR) with regular grid has many challenges like location difference between the renewable energy source and energy distribution point, and characteristic constraints like variability in weather may reduce wind energy, and reduced rain may result in lower hydroelectric energy and so on. In this work, an efficient method is proposed to integrate the RR energy in to the regular power grid. By integrating the RR with conventional energy grid, the user consumption charges can be considerably reduced and, the exploitation of fossil fuels can be gradually reduced. The work also proposes an efficient mechanism to employ real‐time tariff management by demand control center that collects the usage information in real‐time scale. Experimental simulations are performed using MATLAB/SIMULINK environment. For real‐time simulations, fuzzy controller‐ and TCP/IP‐based communication technologies are used. The results show that the proposed work exhibit a better performance against SCADA system, and it shows effective implementation of tariff and energy utility management.