bluuebunny/crossref_metadata_2025 huggingface dataset:
A Promiscuous De Novo Retro‐Aldolase Catalyzes Asymmetric Michael Additions via Schiff Base Intermediates
Authors: Garrabou Xavier , Beck Tobias , Hilvert Donald
Published: March 2015

Recent advances in computational design have enabled the development of primitive enzymes for a range of mechanistically distinct reactions. Here we show that the rudimentary active sites of these catalysts can give rise to useful chemical promiscuity. Specifically, RA95.5‐8, designed and evolved as a retro‐aldolase, also promotes asymmetric Michael additions of carbanions to unsaturated ketones with high rates and selectivities. The reactions proceed by amine catalysis, as indicated by mutagenesis and X‐ray data. The inherent flexibility and tunability of this catalyst should make it a versatile platform for further optimization and/or mechanistic diversification by directed evolution.
Controlling Radical Formation in the Photoactive Yellow Protein Chromophore
Authors: Mooney Ciarán R. S. , Parkes Michael A. , Iskra Andreas , Fielding Helen H.
Published: March 2015

To understand how photoactive proteins function, it is necessary to understand the photoresponse of the chromophore. Photoactive yellow protein (PYP) is a prototypical signaling protein. Blue light triggers trans–cis isomerization of the chromophore covalently bound within PYP as the first step in a photocycle that results in the host bacterium moving away from potentially harmful light. At higher energies, photoabsorption has the potential to create radicals and free electrons; however, this process is largely unexplored. Here, we use photoelectron spectroscopy and quantum chemistry calculations to show that the molecular structure and conformation of the isolated PYP chromophore can be exploited to control the competition between trans–cis isomerization and radical formation. We also find evidence to suggest that one of the roles of the protein is to impede radical formation in PYP by preventing torsional motion in the electronic ground state of the chromophore.
Regioselective Chromatic Orthogonality with Light‐Activated Metathesis Catalysts
Authors: Levin Efrat , Mavila Sudheendran , Eivgi Or , Tzur Eyal , Lemcoff N. Gabriel
Published: March 2015

The ability to selectively guide consecutive chemical processes towards a preferred pathway by using light of different frequencies is an appealing concept. Herein we describe the coupling of two photochemical reactions, one the photoisomerization and consequent activation of a sulfur‐chelated latent olefin‐metathesis catalyst at 350 nm, and the other the photocleavage of a silyl protecting group at 254 nm. Depending on the steric stress exerted by a photoremovable neighboring chemical substituent, we demonstrate the selective formation of either five‐ or six‐membered‐ring frameworks by light‐triggered ring‐closing metathesis. The orthogonality of these light‐induced reactions allows the initiation of these processes independently and in interchangeable order, according to the wavelength of light used to promote them.
Ortho‐Quinone Methides as Reactive Intermediates in Asymmetric Brønsted Acid Catalyzed Cycloadditions with Unactivated Alkenes by Exclusive Activation of the Electrophile
Authors: Hsiao Chien‐Chi , Raja Sadiya , Liao Hsuan‐Hung , Atodiresei Iuliana , Rueping Magnus
Published: March 2015

An efficient method for the highly enantioselective synthesis of chiral chromanes bearing multiple stereogenic centers was developed. A chiral BINOL‐based N‐triflylphosphoramide proved to be an effective catalyst for the in situ generation of ortho‐quinone methides (o‐QMs) and their subsequent cycloaddition reaction with unactivated alkenes provided chromanes with excellent diastereo‐ and enantioselectivity.
Direct C(sp2)C(sp3) Cross‐Coupling of Diaryl Zinc Reagents with Benzylic, Primary, Secondary, and Tertiary Alkyl Halides
Authors: Dunsford Jay J. , Clark Ewan R. , Ingleson Michael J.
Published: March 2015

The direct C(sp2)C(sp3) cross‐coupling of diaryl zinc reagents with benzylic, primary, secondary, and tertiary alkyl halides proceeded in the absence of coordinating ethereal solvents at ambient temperature without the addition of a catalyst. The C(sp2)C(sp3) cross‐coupling showed excellent functional‐group tolerance, and products were isolated in high yields, generally without the requirement for purification by chromatography. This process represents an expedient, operationally simple method for the construction of new C(sp2)C(sp3) bonds.
Intracellular Delivery of Peptidyl Ligands by Reversible Cyclization: Discovery of a PDZ Domain Inhibitor that Rescues CFTR Activity
Authors: Qian Ziqing , Xu Xiaohua , Amacher Jeanine F. , Madden Dean R. , Cormet‐Boyaka Estelle , Pei Dehua
Published: March 2015

A general strategy was developed for the intracellular delivery of linear peptidyl ligands through fusion to a cell‐penetrating peptide and cyclization of the fusion peptides via a disulfide bond. The resulting cyclic peptides are cell permeable and have improved proteolytic stability. Once inside the cell, the disulfide bond is reduced to produce linear biologically active peptides. This strategy was applied to generate a cell‐permeable peptide substrate for real‐time detection of intracellular caspase activities during apoptosis and an inhibitor for the CFTR‐associated ligand (CAL) PDZ domain as a potential treatment for cystic fibrosis.
Heterogeneously Catalyzed Direct CH Thiolation of Heteroarenes
Authors: Vásquez‐Céspedes Suhelen , Ferry Angélique , Candish Lisa , Glorius Frank
Published: March 2015

The first general methodology for the direct thiolation of electron‐rich heteroarenes was developed by employing Pd/Al2O3, a recoverable and commercially available heterogeneous catalyst, and CuCl2. This method represents an operationally simple approach for the synthesis of these valuable compounds. Preliminary mechanistic studies indicate a heterogeneous catalytic system, in which both metals play a complementary role in the formation of the thiolated products.
Characterization of a Palladium Dihydrogen Complex
Authors: Connelly Samantha J. , Chanez Andrew G. , Kaminsky Werner , Heinekey D. Michael
Published: March 2015

The preparation and isolation of the first palladium dihydrogen complex is described. NMR spectroscopy reveals a very short HH bond length, but the hydrogen molecule is activated toward heterolytic cleavage. An X‐ray crystal structure suggests that proton transfer to the tBuPCP (κ3‐2,6‐(tBu2PCH2)2C6H3) pincer ligand is possible. The basicity of the ipso‐carbon atom of the pincer ligand was investigated in a related complex.
Coassembly of Nanorods and Nanospheres in Suspensions and in Stratified Films
Authors: Thérien‐Aubin Héloïse , Lukach Ariella , Pitch Natalie , Kumacheva Eugenia
Published: March 2015

The entropically driven coassembly of nanorods (cellulose nanocrystals, CNCs) and nanospheres (dye‐labeled spherical latex nanoparticles, NPs) was studied in aqueous suspensions and in solid films. In mixed CNC‐latex suspensions, phase separation into an isotropic latex‐NP‐rich and a chiral nematic CNC‐rich phase took place; the latter contained a significant amount of latex NPs. Drying the mixed suspension resulted in CNC‐latex films with planar disordered layers of latex NPs, which alternated with chiral nematic CNC‐rich regions. In addition, fluorescent latex NPs were embedded in the chiral nematic domains. The stratified morphology of the films, together with a random distribution of latex NPs in the anisotropic phase, led to the films having close‐to‐uniform fluorescence, birefringence, and circular dichroism properties.
Highly Regio‐ and Stereoselective Hydrosilylation of Internal Thioalkynes under Mild Conditions
Authors: Ding Shengtao , Song Li‐Juan , Wang Yong , Zhang Xinhao , Chung Lung Wa , Wu Yun‐Dong , Sun Jianwei
Published: March 2015

A general and mild hydrosilylation of thioalkynes is described. With the cationic catalyst [Cp*Ru(MeCN)3]+ and the bulky silane (TMSO)3SiH, a range of thioalkynes underwent smooth hydrosilylation at room temperature with excellent α regioselectivity and syn stereoselectivity. DFT calculations provided important insight into the mechanism, particularly the unusual syn selectivity with the [Cp*Ru(MeCN)3]+ catalyst. The sulfenyl group in the substrates was found to provide important chelation stabilization to direct the reaction through a new mechanistic pathway.
The research for high‐elastic modified asphalt
Authors: Zhang Feng , Hu Changbin
Published: March 2015

High‐elastic modified (HEM) asphalt was prepared by the addition of styrene‐butadiene‐styrene (SBS), plasticizer, and crosslinker to base asphalt. The effect and proportion of each modifier in asphalt were studied using physical and rheological tests. It was found that SBS determined the high‐temperature performance of HEM asphalt mainly. Plasticizer (dioctyl phthalate) is very helpful in improving the low‐temperature flexibility and elastic recovery. Crosslinker (sulfur) is necessary in maintaining high‐temperature stability. In this study, Fourier transform infrared, hydrogen nuclear magnetic resonance analysis, and microscopy observation were used to investigate the structural characteristics of modified asphalts further before and after ageing. The research showed the structural characteristics of modified asphalt were influenced evidently by ageing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42132.
DISTINCTIVE LOCALIZATION OF GROUP 3 LATE EMBRYOGENESIS ABUNDANT SYNTHESIZING CELLS DURING BRINE SHRIMP DEVELOPMENT
Authors: Kim Bo Yong , Song Hwa Young , Kim Mi Young , Lee Bong Hee , Kim Kyung Joo , Jo Kyung Jin , Kim Suhng Wook , Lee Seung Gwan , Lee Boo Hyung
Published: March 2015

Despite numerous studies on late embryogenesis abundant (LEA) proteins, their functions, roles, and localizations during developmental stages in arthropods remain unknown. LEA proteins protect crucial proteins against osmotic stress during the development and growth of various organisms. Thus, in this study, fluorescence in situ hybridization was used to determine the crucial regions protected against osmotic stress as well as the distinctive localization of group 3 (G3) LEA+ cells during brine shrimp development. Several cell types were found to synthesize G3 LEA RNA, including neurons, muscular cells, APH‐1+ cells, and renal cells. The G3 LEA+ neuronal cell bodies outside of the mushroom body projected their axonal bundles to the central body, but those inside the mushroom body projected their axonal bundles toward the deutocerebrum without innervating the central body. The cell bodies inside the mushroom body received axons of the G3 LEA+ sensory cells at the medial ventral cup of the nauplius eye. Several glands were found to synthesize G3 LEA RNA during the nauplius stages of brine shrimp, including the sinus, antennal I and II, salt, and three ectodermal glands. This study provides the first demonstration of the formation of G3 LEA+ sinus glands at the emergence stages of brine shrimp. These results suggest that G3 LEA protein is synthesized in several cell types. In particular, specific glands play crucial roles during the emergence and nauplius stages of brine shrimp.
Synthesis and Photophysics of BF2‐Rigidified Partially Closed Chain Bromotetrapyrroles: Near Infrared Emitters and Photosensitizers
Authors: Dai En , Pang Weidong , Zhang Xian‐Fu , Yang Xudong , Jiang Ting , Zhang Ping , Yu Changjiang , Hao Erhong , Wei Yun , Mu Xiaolong , Jiao Lijuan
Published: March 2015

We report the synthesis, crystallographic, optical, and triplet and singlet oxygen generation properties of a series of BF2‐rigidified partially closed chain bromotetrapyrroles as near infrared emitters and photosensitizers. These novel dyes were efficiently synthesized from a nucleophilic substitution reaction between pyrroles and the 3,5‐bromo‐substituents on the tetra‐ and hexabromoBODIPYs and absorb in the near‐infrared region (681–754 nm) with high molar extinction coefficients. Their fluorescent emission (708–818 nm) and singlet oxygen generation properties are significantly affected by alkyl substitutions on the two uncoordinated pyrrole units of these dyes and the polarity of solvents. Among them, dyes 4 ca and 4 da show good singlet oxygen generation efficiency and good NIR fluorescence emission (fluorescence quantum yields of 0.14–0.43 in different solvents studied).
Dual Functioning Thieno‐Pyrrole Fused BODIPY Dyes for NIR Optical Imaging and Photodynamic Therapy: Singlet Oxygen Generation without Heavy Halogen Atom Assistance
Authors: Watley Ryan L. , Awuah Samuel G. , Bio Moses , Cantu Robert , Gobeze Habtom B. , Nesterov Vladimir N. , Das Sushanta K. , D'Souza Francis , You Youngjae
Published: March 2015

We discovered a rare phenomenon wherein a thieno‐pyrrole fused BODIPY dye (SBDPiR690) generates singlet oxygen without heavy halogen atom substituents. SBDPiR690 generates both singlet oxygen and fluorescence. To our knowledge, this is the first example of such a finding. To establish a structure–photophysical property relationship, we prepared SBDPiR analogs with electron‐withdrawing groups at the para‐position of the phenyl groups. The electron‐withdrawing groups increased the HOMO–LUMO energy gap and singlet oxygen generation. Among the analogs, SBDPiR688, a CF3 analog, had an excellent dual functionality of brightness (82290 m−1 cm−1) and phototoxic power (99170 m−1 cm−1) comparable to those of Pc 4, due to a high extinction coefficient (211 000 m−1 cm−1) and balanced decay (Φflu=0.39 and ΦΔ=0.47). The dual functionality of the lead compound SBDPiR690 was successfully applied to preclinical optical imaging and for PDT to effectively control a subcutaneous tumor.
Distributed Containment Control for Nonlinear Multi‐Agent Systems with Time‐Delayed Protocol
Authors: Hu Jianqiang , Yu Jie , Cao Jinde
Published: March 2015

In this paper, the containment control problem is considered for nonlinear multi‐agent systems with directed communication topology. Under the guidance of designed distributed communication protocols with/without previous state information, the followers are expected to converge to a dynamic convex hull spanned by multiple leaders. Two multi‐step algorithms are proposed to construct the corresponding protocols, the state feedback protocol and the delay‐coupled protocol, under which the containment control can be achieved asymptotically. Furthermore, it is found that the delay‐coupled protocol is rather sensitive to time delays. That is, real‐time tracking will become impossible by only using long‐dated previous state information. Finally, a numerical example is given to demonstrate the applicability and efficiency of the proposed schemes.
Immersion and Invariance Based Robust Adaptive Control of High‐Speed Train with Guaranteed Prescribed Performance Bounds
Authors: Luo Hengyu , Xu Hongze , Liu Xiangbin
Published: March 2015

This paper proposes a novel robust adaptive algorithm for train tracking control with guaranteed prescribed transient and steady‐state performance. As speed increases, the inherent time‐varying uncertainties and unmodeled dynamics in the longitudinal dynamics of a high‐speed train seriously impacts the tracking performance of automatic train operation. To improve train operation performance, an estimator based on immersion and invariance technology is developed to recover the unknown and time‐varying plant parameters, and it renders the estimation error converging to a bounded residual set exponentially while providing more freedom for the controller. After certain error transformation, the prescribed tracking performance is introduced into the controller design. Then, an input‐to‐stable stable controller is developed through the backstepping technique, and it is proven that stabilization of the transformed system is sufficient to guarantee the prescribed performance. Rigorous theoretical analysis for the presented algorithm is provided, and a series of simulation studies also are given to verify the effectiveness of it.
Continuous microwave drying of the seeds of the invasive Chinese tallow tree
Authors: Fennell Laura Picou , Bourgeois Brianna Leilani , Boldor Dorin
Published: March 2015

The Chinese tallow tree (CTT) (Triadica sebifera) is an invasive species in the Southeastern portion of the USA. With lipid content between 40% and 55%, the tree's non‐edible seeds are a valuable source for biofuel production. In situ transesterification is a proposed method for optimizing the transesterification process since it does not require prior oil extraction; however, for yields greater than 98%, the moisture content of the seeds should be less than 2%. In this paper we highlight an innovative microwave assisted drying method, used for the first time for these seeds, as a solution which drastically reduces the drying time and energy consumption compared to other drying methods. To optimize the microwave‐assisted drying of CTT seeds, temperatures of 25 and 55 °C were tested with microwave powers of 0, 200, and 600 W using a continuous microwave drying system. The decrease in moisture content is greatest at 600 W of microwave power, with ambient temperature having little effect on the heat generation. The drying rate to power consumption ratio is greatest with a combination of 600 W at 25 °C ambient temperature. The microwave assisted drying reduced the drying time to about 300 seconds compared to the 4 h required for conventional oven drying. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd
Association of facilitated glucose transporter 2 gene variants with the myelomeningocele phenotype
Authors: Ruggiero Jaclyn E. , Northrup Hope , Au Kit Sing
Published: March 2015

BACKGROUND

Neural tube defects (NTDs) remain the second most common cause of congenital malformations. Myelomeningocele (MM), the most common NTD compatible with survival, results from genetic and environmental factors. Epidemiologic studies and murine models support the hypotheses that obesity, diabetes and hyperglycemia confer increased risk of NTDs. Presence of wild‐type facilitated glucose transporter, Glut2, in mouse embryos has been shown to increase risk for NTDs in hyperglycemic pregnancy.

METHODS

The GLUT2 gene of 96 MM patients was amplified, sequenced and compared with the reference sequence (NM_000340). Variants previously unreported in the single nucleotide polymorphisms (SNP) database were considered novel. Allele frequencies of reported SNPs were compared with reference populations using Fisher's exact test.

RESULTS

Analysis revealed three novel variants: a substitution in the core promoter region (c.−331c>t), a substitution (c.−182g>a) in the 5′‐untranslated region, and a single base pair deletion (c.1441delT) in the coding sequences. Polymorphic alleles for 10 SNPs were also identified. Seven SNPs are significantly associated with MM in the Mexican American patients tested (p < 0.05) and two of the seven remained significant after Bonferroni correction.

CONCLUSION

We identified three novel variants and seven SNPs associated with MM. The novel variants in the core promoter and in the 5′‐untranslated region could affect GLUT2 mRNA transcription and stability and translation efficiency. The c.1441delT variant is predicted to alter the reading frame and prematurely terminate translation of the GLUT2 protein at the C‐terminus, affecting GLUT2 protein function. Presence of GLUT2 variants may disrupt GLUT2 activity and influence MM susceptibility. Birth Defects Research (Part A) 103:479–487, 2015. © 2015 Wiley Periodicals, Inc.
Effect of maternal diabetes on the embryo, fetus, and children: Congenital anomalies, genetic and epigenetic changes and developmental outcomes
Authors: Ornoy Asher , Reece E. Albert , Pavlinkova Gabriela , Kappen Claudia , Miller Richard Kermit
Published: March 2015

Introduction

Pregestational and gestational diabetes mellitus (PGDM; GDM) are significant health concerns because they are associated with an increased rate of malformations and maternal health complications.

Methods

We reviewed the data that help us to understand the effects of diabetes in pregnancy.

Results

Diabetic embryopathy can affect any developing organ system, but cardiovascular and neural tube defects are among the most frequent anomalies. Other complications include preeclampsia, preterm delivery, fetal growth abnormalities, and perinatal mortality. Neurodevelopmental studies on offspring of mothers with diabetes demonstrated increased rate of Gross and Fine motor abnormalities, of Attention Deficit Hyperactivity Disorder, learning difficulties, and possibly also Autism Spectrum Disorder. The mechanisms underlying the effects of maternal hyperglycemia on the developing fetus may involve increased oxidative stress, hypoxia, apoptosis, and epigenetic changes. Evidence for epigenetic changes are the following: not all progeny are affected and not to the same extent; maternal diet may influence pregnancy outcomes; and maternal diabetes alters embryonic transcriptional profiles and increases the variation between transcriptomic profiles as a result of altered gene regulation. Research in animal models has revealed that maternal hyperglycemia is a teratogen, and has helped uncover potential therapeutic targets which, when blocked, can mitigate or ameliorate the negative effects of diabetes on the developing fetus.

Conclusions

Tight metabolic control, surveillance, and labor management remain the cornerstone of care for pregnant women with diabetes, but advances in the field indicate that new treatments to protect the mother and baby are not far from becoming clinical realities. Birth Defects Research (Part C) 105:53–72, 2015. © 2015 Wiley Periodicals, Inc.
The osteochondral interface as a gradient tissue: From development to the fabrication of gradient scaffolds for regenerative medicine
Authors: Di Luca Andrea , Van Blitterswijk Clemens , Moroni Lorenzo
Published: March 2015

The osteochondral (OC) interface is not only the interface between two tissues, but also the evolution of hard and stiff bone tissue to the softer and viscoelastic articular cartilage covering the joint surface. To generate a smooth transition between two tissues with such differences in many of their characteristics, several gradients are recognizable when moving from the bone side to the joint surface. It is, therefore, necessary to implement such gradients in the design of scaffolds to regenerate the OC interface, so to mimic the anatomical, biological, and physicochemical properties of bone and cartilage as closely as possible. In the past years, several scaffolds were developed for OC regeneration: biphasic, triphasic, and multilayered scaffolds were used to mimic the compartmental nature of this tissue. The structure of these scaffolds presented gradients in mechanical, physicochemical, or biological properties. The use of gradient scaffolds with already differentiated or progenitor cells has been recently proposed. Some of these approaches have also been translated in clinical trials, yet without the expected satisfactory results, thus suggesting that further efforts in the development of constructs, which can lead to a functional regeneration of the OC interface by presenting gradients more closely resembling its native environment, will be needed in the near future. The aim of this review is to analyze the gradients present in the OC interface from the early stage of embryonic life up to the adult organism, and give an overview of the studies, which involved gradient scaffolds for its regeneration. Birth Defects Research (Part C) 105:34–52, 2015. © 2015 Wiley Periodicals, Inc.
Thermal effects of 2450 MHz microwave exposure near a titanium alloy plate implanted in rabbit limbs
Authors: Ye Dongmei , Xu Yiming , Wang Gang , Feng Xianxuan , Fu Tengfei , Zhang Han , Jiang Lan , Bai Yuehong
Published: March 2015

This study aimed to examine the safety profile of microwave therapy on limbs with metal implants. New Zealand white rabbits were implanted with titanium alloy internal fixation plates. Femurs were exposed to 20, 40, 60, or 80 W of microwave radiation for 30 min (microwave applicator at 2450 MHz), and temperatures of the implants and muscles adjacent to implants were recorded. To evaluate thermal damage, nerves were electrodiagnostically assessed immediately after radiation, and histologic studies performed on nerve and muscle sections. As expected, implant temperature was highest in the exposure field. Temperatures of limbs with titanium alloy implants increased significantly at 60 and 80 W, with a significant decline in the nerve conduction velocity and acute thermal injuries in nerves and muscles adjacent to implants. However, temperature remained unchanged and no adverse effects were observed in nerves and muscles at 20 and 40 W. These findings are inconsistent with the current notion that surgical metal implants in the treatment field are contraindications for microwave therapy. Hence, we believe that a lower dose of continuous wave microwave irradiation is safe for limbs with titanium alloy implants. Bioelectromagnetics. 36:309–318, 2015. © 2015 Wiley Periodicals, Inc.
Validation of a HPLC‐ESI MS/MS method for the determination of clonidine in human plasma and its application in a bioequivalence study in Chinese healthy volunteers
Authors: Zhuang Jialang , Chen Jiangying , Wang Xueding , Pang Yin , Bi Huichang , Huang Lihui , Zeng Guixiong , Liao Xiaoxing , Ma Zhongfu , Chen Xiao , Zhong Guoping , Huang Min , Zhao Xianglan
Published: March 2015

A rapid and sensitive liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS) method to determine clonidine in human plasma was developed and fully validated. Sample preparation was involved an one‐step extraction with diethyl ether. Donepezil was employed as the internal standard (IS). Chromatographic separation was performed on a Hypersil BDS C18 column (i.d. 2.1 × 50 mm, particle size 3μm) with a mobile phase of methanol–water (containing 0.1% formic acid; 60:40, v/v) at a flow rate of 200 μL/min. The peaks were detected by mass spectrometry using the electrospray ion source in selected reaction monitoring mode. The extraction recovery was 72.53–85.25%. The method was found to be linear in a concentration range of 0.02–6.00 ng/mL and the lower limit of quantification was 0.02 ng/mL. The within‐ and between‐batch precisions at three concentrations were 4.33–16.47 and 7.24–17.24% with accuracies of −2.47–10.91 and 1.86–10.19%, respectively. This validated method was successfully used for a bioequivalence study of two clonidine transdermal patches on healthy volunteers. The results suggested that the test formulation of clonidine patch met the regulatory criterion for bioequivalence to the reference formulation, but a larger sample size should be needed for the estimation of bioequivalence. Copyright © 2015 John Wiley & Sons, Ltd.
Design of an experimental twin‐rotor multi‐input multi‐output system
Authors: Bayrak Alper , Dogan Firat , Tatlicioglu Enver , Ozdemirel Barbaros
Published: March 2015

Twin‐rotor multi‐input multi‐output system (TRMS) is a popular experimental setup utilized mostly for development and evaluation of aerovehicle control algorithms. Motivated by its popularity, construction steps of a TRMS setup in an academic setting are presented in this paper. Specifically, design of mechanical and electronic hardware components and development of related computer software are described in detail. Preliminary experiment results are also presented to demonstrate the performance of the system. © 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:578–586, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21628
Demonstrating students' skills on integrating knowledge of math and engineering in an applied programming course in civil engineering
Authors: Oreta Andres Winston C. , Balili Alden Paul
Published: March 2015

Innovative approaches in teaching and learning can be introduced in the classroom using the computer. In a laboratory class on Computer Methods in Civil Engineering at De La Salle University, students develop simple computer software applications and computer‐based games on topics related to civil engineering using Visual Basic. By creating their own software applications, the students demonstrate the student outcomes on application of mathematics, science and engineering in solving engineering problems using modern engineering tools. © 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:630–637, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21637
Lexical analysis of student research drafts in computing
Authors: González‐López Samuel , López‐López Aurelio
Published: March 2015

Lexical Richness is a competence that students acquire while advancing in education. This article presents results analyzing lexical richness of drafts of students, in terms of lexical density, variety, and sophistication. A computational model allows reviewing some essential elements in drafts. Results show that there exists a difference in lexical richness between graduate and undergraduate texts, and that sophistication is the measure that best differentiates them. We also report results of a pilot test. © 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:638–644, 2015; View this article online atwileyonlinelibrary.com/journal/cae; DOI10.1002/cae.21638
Using educational software to enhance the teaching & learning in computer integrated manufacturing: Material requirements planning module
Authors: Cvetić Biljana , Ilić Oliver R.
Published: March 2015

The material requirements planning (MRP) is a traditional topic in operations management and industrial engineering education. This paper presents an application of custom‐made selection procedure of MRP educational software. The results of evaluation from the three generations of students showed that the selected MRP educational software was very useful in acquiring advanced students’ MRP skills. © 2015 Wiley Periodicals, Inc. Comput. Appl. Eng. Educ. Comput Appl Eng Educ 23:682–693, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21641
Palladium‐Catalyzed Direct Arylation of Allylamines with Simple Arenes
Authors: Lei Yichao , Qiu Ruiying , Zhang Lingjuan , Xu Conghui , Pan Yixiao , Qin Xubo , Li Huanrong , Xu Lijin , Deng Yuheng
Published: March 2015

The Pd(OAc)2‐catalyzed direct CH bond olefination of unreactive arenes with allylamines in the presence of AgOAc was developed. A variety of allylamines including β‐substituted substrates underwent smooth coupling reactions with various arenes to give exclusively the terminal arylation products in high yields with excellent regioselectivities and stereoselectivities. The reaction is compatible with a range of functional groups in both coupling partners. The carbonyl group in the allylamine substrates is critical to catalysis, and the high regio‐ and stereocontrol observed is attributed to coordination between the carbonyl O and Pd atoms.
Efficient Biosynthesis of Ethyl (R)‐3‐Hydroxyglutarate through a One‐Pot Bienzymatic Cascade of Halohydrin Dehalogenase and Nitrilase
Authors: Yao Peiyuan , Wang Lei , Yuan Jing , Cheng Lihua , Jia Rongrong , Xie Meixian , Feng Jinhui , Wang Min , Wu Qiaqing , Zhu Dunming
Published: March 2015

An effective one‐pot bienzymatic synthesis of ethyl (R)‐3‐hydroxyglutarate (EHG) from ethyl (S)‐4‐chloro‐3‐hydroxybutyrate (ECHB) was achieved by using recombinant Escherichia coli cells expressing separately or co‐expressing a mutant halohydrin dehalogenase gene from Agrobacterium radiobacter AD1 and a nitrilase gene from Arabidopsis thaliana. The activity of nitrilase was inhibited by high concentration of ECHB and NaCN. Consequently, the one‐pot one‐step process was implemented by fed‐batch of ECHB and NaCN with high accumulative product concentration (up to 0.9 mol L−1). The biotransformation of ECHB to EHG was successfully achieved at 1.2 mol L−1 substrate concentration by a one‐pot two‐step process. As such, this one‐pot bienzymatic transformation should be useful in synthesizing these important optical pure β‐hydroxycarboxylic acids.
Assessments of Surface Coverage after Nanomaterials are Drop Cast onto Electrodes for Electroanalytical Applications
Authors: Chan Ya Yun , Eng Alex Y. S. , Pumera Martin , Webster Richard D.
Published: March 2015

The drop‐casting method for the suspension of nanomaterials on conducting surfaces is a commonly used procedure for evaluating the electrochemical properties of the drop‐cast materials. In this study, we pinpoint a key limitation of the method, which may lead to misinterpretation of the obtained data, especially when evaluating heterogeneous electron‐transfer rates. The electrochemical responses recorded at 1 mm‐diameter copper electrodes modified with porous layers of drop‐cast multiwalled carbon nanotubes (MWCNTs) in 0.1 M Na2SO4 aqueous solutions were examined. Standard amounts of the MWCNTs that are typically used for the drop‐casting procedure (1 mg MWCNT in 1 mL of dimethylformamide) were deposited drop wise on the surface of the copper electrodes. Layers of MWCNTs were progressively built up on the electrode surface by varying the number of drops from 0 to 10. The ability of the MWCNTs to cover and prevent diffusion to the base copper electrode was assessed by performing oxidative cyclic (CV) and linear‐sweep voltammetry (LSV) experiments in the presence of aggressive SO42− supporting electrolyte, where a large oxidative current indicated the occurrence of corroding copper metal. It was demonstrated that a total of 10 drops of the coating solution (equivalent to 640 μg cm−2 of MWCNTs per unit area) was still insufficient in providing complete coverage over the underlying electrode surface (as a corrosion current was still observed), even though considerably lower CNT loadings have been applied in many literature reports. The electrochemical results indicate that, for experiments that utilize the drop‐casting procedure to modify electrode surfaces, it cannot be assumed that the base electrode, nor the pore structure of the coating material, does not significantly contribute to the overall observed voltammetric response.
Rationalising the Geometric Variation between the A and B Monomers in the 1.9 Å Crystal Structure of Photosystem II
Authors: Petrie Simon , Stranger Robert , Pace Ron J.
Published: March 2015

Density functional theory calculations are reported on a set of models of the water‐oxidising complex (WOC) of photosystem II (PSII), exploring structural features revealed in the most recent (1.9 Å resolution) X‐ray crystallographic studies of PSII. Crucially, we find that the variation in the Mn–Mn distances seen between the A and B monomers of this crystal structure can be entirely accounted for, in the low oxidation state (LOS) paradigm, by consideration of the interplay between two hydrogen‐bonding interactions involving proximate amino acid residues with the oxo bridges of the WOC, that is, His337 with O3 (which leads to a general elongation in the Mn–Mn distances between Mn1, Mn2 and Mn3) and Arg357 with O2 (which results in a specific elongation of the Mn2Mn3 distance).
Tuning Coordination in s‐Block Carbazol‐9‐yl Complexes
Authors: Ortu Fabrizio , Moxey Graeme J. , Blake Alexander J. , Lewis William , Kays Deborah L.
Published: March 2015

1,3,6,8‐Tetra‐tert‐butylcarbazol‐9‐yl and 1,8‐diaryl‐3,6‐di(tert‐butyl)carbazol‐9‐yl ligands have been utilized in the synthesis of potassium and magnesium complexes. The potassium complexes (1,3,6,8‐tBu4carb)K(THF)4 (1; carb=C12H4N), [(1,8‐Xyl2‐3,6‐tBu2carb)K(THF)]2 (2; Xyl=3,5‐Me2C6H3) and (1,8‐Mes2‐3,6‐tBu2carb)K(THF)2 (3; Mes=2,4,6‐Me3C6H2) were reacted with MgI2 to give the Hauser bases 1,3,6,8‐tBu4carbMgI(THF)2 (4) and 1,8‐Ar2‐3,6‐tBu2carbMgI(THF) (Ar=Xyl 5, Ar=Mes 6). Structural investigations of the potassium and magnesium derivatives highlight significant differences in the coordination motifs, which depend on the nature of the 1‐ and 8‐substituents: 1,8‐di(tert‐butyl)‐substituted ligands gave π‐type compounds (1 and 4), in which the carbazolyl ligand acts as a multi‐hapto donor, with the metal cations positioned below the coordination plane in a half‐sandwich conformation, whereas the use of 1,8‐diaryl substituted ligands gave σ‐type complexes (2 and 6). Space‐filling diagrams and percent buried volume calculations indicated that aryl‐substituted carbazolyl ligands offer a steric cleft better suited to stabilization of low‐coordinate magnesium complexes.
Thermal Conversion of Methane to Formaldehyde Promoted by Gold in AuNbO3+ Cluster Cations
Authors: Wang Li‐Na , Zhou Zhen‐Xun , Li Xiao‐Na , Ma Tong‐Mei , He Sheng‐Gui
Published: March 2015

In addition to generation of a methyl radical, formation of a formaldehyde molecule was observed in the thermal reaction of methane with AuNbO3+ heteronuclear oxide cluster cations. The clusters were prepared by laser ablation and mass‐selected to react with CH4 in an ion‐trap reactor under thermal collision conditions. The reaction was studied by mass spectrometry and DFT calculations. The latter indicated that the gold atom promotes formaldehyde formation through transformation of an AuO bond into an AuNb bond during the reaction.
Formal Total Synthesis of Aliskiren
Authors: Peters Byron K. , Liu Jianguo , Margarita Cristiana , Andersson Pher G.
Published: March 2015

The efficient and selective formal total synthesis of aliskiren is described. Aliskiren, a renin inhibitor drug, has received considerable attention, primarily because it is the first of the renin inhibitor drugs to be approved by the FDA. Herein, the formal synthesis of aliskiren by iridium‐catalyzed asymmetric hydrogenation of two allylic alcohol fragments is reported. Screening a number of N,P‐ligated iridium catalysts yielded two catalysts that gave the highest enantioselectivity in the hydrogenation, which gave the saturated alcohols in 97 and 93 % ee. In only four steps after hydrogenation, the fragments were combined by using the Julia–Kocienski reaction to produce late‐stage intermediate in an overall yield of 18 %.
Controlled Formation of Fluorescent Metalloporphyrin‐Containing Coordination Polymer Particles from Seed Structures by Designed Shape‐Transformation Reactions
Authors: Sun Yu , Li Xiaopeng , Caravella Alessio , Gao Rongke
Published: March 2015

Herein, nanorod structures and four‐leaf clover structures of fluorescent zinc 5,10,15,20‐tetra(4‐pyridyl)‐21H,23H‐porphine (ZnTPyP)‐containing coordination polymer particles (CPPs) were first synthesized by a bottom‐up strategy assisted by surfactants and then employed as seed structures for further shape‐transformation reactions. We have successfully designed the morphological transformation for different dimensions, achieving the controlled formation of octahedron structures at both the nanometer scale and micrometer scale from the seed structures. Our approach illustrates a new method to design and synthesize metalloporphyrin‐containing CPPs in a systematic and controllable manner.
Photocurrent Generation through Charge‐Transfer Processes in Noncovalent Perylenediimide/DNA Complexes
Authors: Takada Tadao , Ido Misa , Ashida Akane , Nakamura Mitsunobu , Fujitsuka Mamoru , Kawai Kiyohiko , Majima Tetsuro , Yamana Kazushige
Published: March 2015

The charge‐transfer process in noncovalent perylenediimide (PDI)/DNA complexes has been investigated by using nanosecond laser flash photolysis (LFP) and photocurrent measurements. The PDI/DNA complexes were prepared by inclusion of cationic PDI molecules into the artificial cavities created inside DNA. The LFP experiments showed that placement of the PDI chromophore at a specific site and included within the base stack of DNA led to the efficient generation of a charge‐separated state with a long lifetime by photoexcitation. When two PDI chromophores were separately placed at different positions in DNA, the yield of the charge‐separated state with a long lifetime was dependent upon the number of A–T base pairs between the PDIs, which was explained by electron hopping from one PDI to another. Photocurrent generation of the DNA‐modified electrodes with the complex was also dependent upon the arrangement of the PDI chromophores. A good correlation was obtained between observed charge separation and photocurrent generation on the PDI/DNA‐modified electrodes, which demonstrated the importance of the defined arrangement and assembly of organic chromophores in DNA for efficient charge separation and transfer in multichromophore arrays.
Synthesis and Biological Evaluation of RGD Peptidomimetic–Paclitaxel Conjugates Bearing Lysosomally Cleavable Linkers
Authors: Dal Corso Alberto , Caruso Michele , Belvisi Laura , Arosio Daniela , Piarulli Umberto , Albanese Clara , Gasparri Fabio , Marsiglio Aurelio , Sola Francesco , Troiani Sonia , Valsasina Barbara , Pignataro Luca , Donati Daniele , Gennari Cesare
Published: March 2015

Two small‐molecule–drug conjugates (SMDCs, 6 and 7) featuring lysosomally cleavable linkers (namely the Val–Ala and Phe–Lys peptide sequences) were synthesized by conjugation of the αvβ3‐integrin ligand cyclo[DKP–RGD]‐CH2NH2 (2) to the anticancer drug paclitaxel (PTX). A third cyclo[DKP–RGD]–PTX conjugate with a nonpeptide “uncleavable” linker (8) was also synthesized to be tested as a negative control. These three SMDCs were able to inhibit biotinylated vitronectin binding to the purified αVβ3‐integrin receptor at nanomolar concentrations and showed good stability at pH 7.4 and pH 5.5. Cleavage of the two peptide linkers was observed in the presence of lysosomal enzymes, whereas conjugate 8, which possesses a nonpeptide “uncleavable” linker, remained intact under these conditions. The antiproliferative activities of the conjugates were evaluated against two isogenic cell lines expressing the integrin receptor at different levels: the acute lymphoblastic leukemia cell line CCRF‐CEM (αVβ3−) and its subclone CCRF‐CEM αVβ3 (αVβ3+). Fairly effective integrin targeting was displayed by the cyclo[DKP–RGD]–Val–Ala–PTX conjugate (6), which was found to differentially inhibit proliferation in antigen‐positive CCRF‐CEM αVβ3 versus antigen‐negative isogenic CCRF‐CEM cells. The total lack of activity displayed by the “uncleavable” cyclo[DKP–RGD]–PTX conjugate (8) clearly demonstrates the importance of the peptide linker for achieving the selective release of the cytotoxic payload.
Enantioselective Template‐Directed [2+2] Photocycloadditions of Isoquinolones: Scope, Mechanism and Synthetic Applications
Authors: Coote Susannah C. , Pöthig Alexander , Bach Thorsten
Published: March 2015

A strategy for the enantioselective [2+2] photocycloaddition of isoquinolones with alkenes is presented, in which the formation of a supramolecular complex between a chiral template and the substrate ensures high enantioface differentiation by shielding one face of the substrate. Fifteen different electron‐deficient alkenes and ten different substituted isoquinolones undergo efficient photocycloaddition, yielding the cyclobutane products in excellent yields and with outstanding regio‐, diastereo‐ and enantioselectivities (up to 99 % ee). The mechanism of the reaction is investigated by means of triplet sensitization/quenching and radical clock experiments, the results of which are consistent with the involvement of a triplet excited state and a 1,4‐biradical intermediate. The variety of functionalized cyclobutanes obtained using this approach can be further increased by straightforward synthetic transformations of the photoadducts, allowing rapid access to libraries of compounds for various applications.
Bioinspired Hierarchical Nanotubular Titania Immobilized with Platinum Nanoparticles for Photocatalytic Hydrogen Production
Authors: Liu Xiaoyan , Li Jiao , Zhang Yiming , Huang Jianguo
Published: March 2015

A bioinspired nanocomposite composed of platinum nanoparticles and nanotubular titania was fabricated in which the titania matter was templated by natural cellulose substance. The composite possesses three‐ dimensional hierarchical structures, and ultrafine metallic platinum particles with sizes of ca. 2 nm were immobilized uniformly on the surfaces of the titania nanotubes. Such a nanocomposite with 1.06 wt % of platinum content shows the optimal photocatalytic hydrogen production activity from water splitting of 16.44 mmol h−1 g−1, and excessive loading of platinum results in poorer photocatalytic performance. The structural integrity of the nanocomposite upon cyclic water‐splitting processes results in its sufficient photocatalytic stability.
Comparative Analysis of Coalescence and Breakage Kernels in Vertical Gas‐Liquid Flow
Authors: Deju Lilunnahar , Cheung Sherman Chi Pok , Yeoh Guan Heng , Qi Fengsheng , Tu Jiyuan
Published: March 2015

The evolution of bubble size distribution is an important consideration in vertical gas‐liquid flow, especially in determining the appropriate mass, momentum, and heat transfer between two phases. In order to adequately capture the distribution and to account for its effect on the local hydrodynamics, which generally represents the dominant flow characteristic in such a practical system, a numerical assessment has been performed to understand the six widely adopted different bubble coalescence and bubble breakage kernels. Three different breakage kernels have been selected where each kernel considers a different shape of the daughter size distribution of the bubbles, such as the U‐shape, bell‐shape, and M‐shape. These are combined with different coalescence kernels. The bubble size distribution, void fraction, interfacial area concentration, and gas velocity profiles are compared against the experimental data. Numerical results reveal that the effect on the two‐phase flow structure is mainly due to the application of the different breakage kernels. Moreover, the predicted results also show that the bell‐shape daughter size distribution favours equal breakage of bubbles, which could lead to the over‐prediction of large bubbles. A more sophisticated model for handling bubble induced turbulence should nonetheless be applied in future investigations of vertical gas‐liquid flow.
Breast cancer risk after full‐term pregnancies among African women from Nigeria, Cameroon, and Uganda
Authors: Sighoko Dominique , Ogundiran Temidayo , Ademola Adeyinka , Adebamowo Clement , Chen Lin , Odedina Stella , Anetor Imaria , Ndom Paul , Gakwaya Antony , Ojengbede Oladosu , Huo Dezheng , Olopade Olufunmilayo I.
Published: March 2015

BACKGROUND

The breast cancer (BC) risk profiles of African women differ significantly from those of women of European ancestry. African women are younger at the age of onset and tend to have high parity. The purpose of this study was to examine the relationship between full‐term pregnancy (FTP) and the risk of BC.

METHODS

A case‐control study was conducted among 1995 women with invasive BC and 2631 controls in Nigeria, Cameroon, and Uganda. Odds ratios (ORs) for individual ages at FTP according to the time since delivery were calculated and adjusted for confounders. A fitted spline model was used to assess the impact of the number of pregnancies on BC risk.

RESULTS

In comparison with a nulliparous woman, a parous woman with her first FTP at 20 years showed an OR of 0.76 (95% confidence interval [CI], 0.57‐0.99) for developing BC in the following 5 years. Ten years later, this risk was 0.76 (95% CI, 0.58‐0.99) and 0.76 (95% CI, 0.58‐0.98) for women aged 25 and 30 years, respectively. Similarly, a parous woman with 1 pregnancy had an OR of 0.69 (95% CI, 0.49‐0.96), whereas the OR was 0.66 (95% CI, 0.48‐0.91) with 2 or 5 pregnancies and 0.67 (95% CI, 0.47‐0.94) with 6 pregnancies in comparison with nulliparous women.

CONCLUSIONS

In contrast to studies in women of European ancestry, this study showed no transient increase in the risk of developing BC after FTP among African women. Further studies are needed to examine the impact of reproductive factors on early‐onset BC in African women. Cancer 2015;121:2237–2243. © 2015 American Cancer Society.