bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of Competency‐Based Learning: Tools, Assessments, and Recommendations
Authors: Henri Maria , Johnson Michael D. , Nepal Bimal
Published: November 2017

Background

Over the past decade, there has been a shift in science, technology, engineering and math education, especially in engineering, towards a competency‐based pedagogy. Competency‐based learning (CBL) is an outcome‐based, student‐centered form of instruction where students progress to more advanced work upon mastering the necessary prerequisite content and skills. Many articles have been published on the implementation of CBL in engineering higher education; however, the literature lacks a systematic review that summarizes prior work to inform both future research and practice.

Purpose

The purpose of this review is to integrate previous literature as well as identify gaps in competency‐based engineering higher education research. It summarizes the different approaches for implementing CBL, the effects of the pedagogy on student outcomes, tools to enhance its effectiveness, and assessment strategies. In addition, suggestions and recommendations for future research are provided.

Method

Engineering education articles were obtained from several EBSCO educational databases. The search was limited to articles published from 2005‐2015, and inclusion criteria consisted of peer‐reviewed journal articles that address the use of CBL in engineering higher education. Articles were then classified into several categories, summarized, and evaluated.

Conclusions

Theoretical and applied perspectives are provided that address both the theoretical basis for the effectiveness of CBL and practical aspects of implementing successful CBL instruction in engineering education. There are gaps in the literature regarding how CBL programs should be structured and assessed. Future research directions include empirical quantitative evaluation of CBL's pedagogical effectiveness and the use of CBL for teaching professional skills.
Concise Synthesis and Pharmacological Applications of New α‐Lapachone Analogues
Authors: Hamama Wafaa S. , Hassanien Alaa E. , Zoorob Hanafi H.
Published: November 2017

Synthesis of novel 1,4‐naphthoquinones structurally related to α‐lapachone skeleton and its annulated compounds were synthesized from lawsone (2‐hydroxynaphthalene‐1,4‐dione). Pharmacological studies provided indication of biological activities, including effects against hepatocellular carcinoma (HePG‐7) and mammary gland breast cancer (MCF‐7). The molecular structures of the target molecules were examined.
Synthesis of Some New Polyfunctionalized Pyridines
Authors: Amer A. A
Published: November 2017

5‐Methyl‐2,4‐dihydro‐3H‐pyrazol‐3‐one and/or 5‐methyl‐2‐phenyl‐2,4‐dihydro‐3H‐pyrazol‐3‐one was reacted with arylidenemalononitrile in the presence of sodium alkoxide to give 2‐amino‐6‐alkoxy‐4‐arylpyridine‐3,5‐dicarbonitrile 4a–e instead of the reported pyrazolo[3,4‐b]pyridine‐5‐carbonitriles. The same products 4a–e were prepared via reaction of arylidenemalononitrile with sodium alkoxide in an appropriative alcohol. However, the new synthetic route for preparation of their positional isomer 4‐amino‐6‐alkoxy‐2‐arylpyridine‐3,5‐dicarbonitrile 7a–j has been achieved via reaction of 2‐aminoprop‐1‐ene‐1,1,3‐tricarbonitrile with different aromatic aldehydes under the same conditions.
A Simple and Facile Synthesis of 4‐Phenylquinoline‐fused Pyrrolidin‐2‐ones
Authors: Li Yang , Zou Hongtao
Published: November 2017

In the present investigation, a simple and facile synthesis of a series of 4‐phenylquinoline‐fused pyrrolidin‐2‐ones, namely, 9‐phenyl‐2‐substituted‐2,3‐dihydro‐1H‐pyrrolo[3,4‐b]quinolin‐1‐ones is described, involving the tandem intermolecular C‐N bond formation reaction between readily available ethyl 2‐(chloromethyl)‐4‐phenylquinoline‐3‐carboxylate and various amines followed by in situ intramolecular C–N bond cyclization process in the presence of EtOH‐AcOH (v/v, 10:1) solvent system as the reaction medium.
Breast lesion characterization using whole‐lesion histogram analysis with stretched‐exponential diffusion model
Authors: Liu Chunling , Wang Kun , Li Xiaodan , Zhang Jine , Ding Jie , Spuhler Karl , Duong Timothy , Liang Changhong , Huang Chuan
Published: November 2017

Background

Diffusion‐weighted imaging (DWI) has been studied in breast imaging and can provide more information about diffusion, perfusion and other physiological interests than standard pulse sequences. The stretched‐exponential model has previously been shown to be more reliable than conventional DWI techniques, but different diagnostic sensitivities were found from study to study.

Purpose

This work investigated the characteristics of whole‐lesion histogram parameters derived from the stretched‐exponential diffusion model for benign and malignant breast lesions, compared them with conventional apparent diffusion coefficient (ADC), and further determined which histogram metrics can be best used to differentiate malignant from benign lesions.

Study Type

This was a prospective study.

Population

Seventy females were included in the study.

Field Strength/Sequence

Multi‐b value DWI was performed on a 1.5T scanner.

Assessment

Histogram parameters of whole lesions for distributed diffusion coefficient (DDC), heterogeneity index (α), and ADC were calculated by two radiologists and compared among benign lesions, ductal carcinoma in situ (DCIS), and invasive carcinoma confirmed by pathology.

Statistical Tests

Nonparametric tests were performed for comparisons among invasive carcinoma, DCIS, and benign lesions. Comparisons of receiver operating characteristic (ROC) curves were performed to show the ability to discriminate malignant from benign lesions.

Results

The majority of histogram parameters (mean/min/max, skewness/kurtosis, 10–90th percentile values) from DDC, α, and ADC were significantly different among invasive carcinoma, DCIS, and benign lesions. DDC10% (area under curve [AUC] = 0.931), ADC10% (AUC = 0.893), and αmean (AUC = 0.787) were found to be the best metrics in differentiating benign from malignant tumors among all histogram parameters derived from ADC and α, respectively. The combination of DDC10% and αmean, using logistic regression, yielded the highest sensitivity (90.2%) and specificity (95.5%).

Data Conclusion

DDC10% and αmean derived from the stretched‐exponential model provides more information and better diagnostic performance in differentiating malignancy from benign lesions than ADC parameters derived from a monoexponential model.

Level of Evidence: 2

Technical Efficacy: Stage 2

J. Magn. Reson. Imaging 2018;47:1701–1710.
Role of two 5‐aminolevulinic acid biosynthetic pathways in heme and secondary metabolite biosynthesis in Amycolatopsis orientalis
Authors: Zhu Li , Qian Xiuping , Chen Daijie , Ge Mei
Published: November 2017

Analysis of the Amycolatopsis orientalis genome revealed that two genes, hemA1 and hemA2, belonging to divergent pathways, were involved in the biosynthesis of 5‐aminolevulinic acid. The roles of hemA1 and hemA2 were elucidated via genetic manipulation and metabolite analysis. The disruption of hemA1, encoding the glutamyl‐tRNAGlu reductase of the C5 pathway, was essential for cell growth and is used for heme synthesis. Overexpression of hemA1 resulted in elevated vancomycin and ECO‐0501 production in Amycolatopsis orientalis, and it was also effective in increasing the production of daptomycin and natamycin in other Streptomycetes. The disruption of hemA2 indicated that it encodes the 5‐aminolevulinic acid synthase of the Shemin pathway, serving as a key enzyme for the synthesis of the precursor aminohydroxycyclopentenone unit of ECO‐0501. However, hemA2 disruption could not be complemented by the addition of 5‐aminolevulinic acid or by the expression of hemA2 outside of the ECO‐0501 gene cluster. The synthesis of ECO‐0501 was only restored by the insertion of hemA2 at its original locus. The hemA2 gene could partly complement the hemA1 deficiency. Overexpression of hemA1, a key gene from the heme biosynthetic pathway, is proposed here as a new approach to improve the production of secondary metabolites in bacteria, whereas hemA2 plays different roles depending on its pattern of expression.
Intensified influence of the ENSO Modoki on boreal summer tropical cyclone genesis over the western North Pacific since the early 1990s
Authors: Liu Yong , Chen Guanghua
Published: November 2017

This study presents the inter‐decadal intensified impact of the ENSO Modoki (ENM) on tropical cyclone (TC) genesis over the western North Pacific (WNP) since the early 1990s. We find that this intensified impact may be largely attributed to the inter‐decadal change of the spatio‐temporal variability of the ENM, which includes an increasing period and expansive sea surface temperature (SST) anomaly over the central Pacific after the early 1990s. Because of the inter‐decadal change of the ENM, especially the expansive SST pattern, the response of large‐scale atmospheric circulation was enhanced and had expanded northwards and westwards since the early 1990s, which has led to significant TC genesis anomalies over a large fraction of the WNP. The spatial changes of the ENM may possibly be modulated by the inter‐decadal SST change over the Pacific.
Medical industry at tumor board: Three‐years analysis of the open payments database and comparison of oncologic specialties
Authors: Baadh Amanjit S. , Patel Mikin , Patel Ketan , Ahmed Osman
Published: November 2017

Background and Objectives

To analyze and contrast medical industry payments across U.S. oncologic providers, including hematology‐oncology (HO), surgical oncology (SO), interventional radiology (IR), and radiation oncology (RO).

Methods

Open‐payment‐data for each provider including provider specialty, state of practice, industry payor, reason for payment, and amount was compiled for each transaction between 2013 and 2015. Total, mean, and median payment amounts per‐provider were calculated for each specialty. Tukey's‐method was used to identify and remove statistical outliers and Kruskal‐Wallis‐test with Bonferonni‐post‐hoc‐analysis was used to evaluate for differences in total payments received per‐provider across specialties. The percentage of providers accepting payments within each specialty were compared by Marascuilo's multiple‐proportion‐comparison.

Results

Total aggregate payment amount (and number of transactions) for HO, SO, IR, and RO was $164 743 746 (778 007), $7 925 467 (15 031), $49 817 380 (44 939), and $13 643 739 (49 778), respectively. Corrected‐median (and corrected‐mean) payments‐per‐specialty were $676 ($1796), $330 ($1209), $487 ($1301), and $242 ($766). A significantly higher proportion of HO providers accepted payments than both RO (97% vs 80%, P < 0.0001) and IR (97% vs 78%, P < 0.0001). The mean total payment received per‐provider differed significantly across specialties (P = 0.0001). HO providers, on average, received significantly more payment‐per‐provider during the study period (P < 0.001) compared to all others while RO and IR received significantly less (P < 0.0001).

Conclusions

Among industry payments made to oncologic providers, HO received the highest median and corrected‐mean amounts along with the highest proportion of providers receiving open payments.
Determining Candidate Single Nucleotide Polymorphisms in Acquired Laryngotracheal Stenosis
Authors: Anis Mursalin M. , Krynetskaia Natalia , Zhao Zhigen , Krynetskiy Evgeny , Soliman Ahmed M. S.
Published: November 2017

Objectives/Hypothesis

Despite wide adoption of strategies to prevent injury from prolonged intubation and tracheotomy, acquired laryngotracheal stenosis (ALTS) has not disappeared. ALTS’ persistence may be due to patient factors that confer unique susceptibility for some. We sought to identify genetic markers in genes associated with wound healing that could be associated with ALTS.

Study Design

Case‐control study.

Methods

One hundred thirty‐eight patients were recruited, 53 patients with ALTS and 85 control patients who underwent intubation or tracheotomy without evidence of ALTS. The patients’ DNA was isolated from whole blood. Custom primers were designed, and the TaqMan assay employing allele‐specific polymerase chain reaction was used to interrogate single nucleotide polymorphisms (SNPs) rs1799750, rs522616, rs2276109, rs2569190, rs1800469, and rs1024611 of candidate wound healing genes MMP1, MMP3, MMP12, CD14, TGFβ1, and MCP1, respectively. A logistic regression model was used to examine the association of candidate gene polymorphisms with the presence or absence of ALTS.

Results

All 138 patients were successfully genotyped. No significant association was found between candidate SNPs and development of ALTS in the overall group. However, subgroup analysis within each ethnicity identified SNPs that are associated with ALTS depending upon the ethnic background.

Conclusions

Patient factors such as variations in wound healing due to functional SNPs may shed light on the development of ALTS. There may be a difference in susceptibility to developing ALTS in different ethnic backgrounds. These preliminary findings need to be corroborated in larger population studies.

Level of Evidence

3b. Laryngoscope, 128:E111–E116, 2018
When and where did the Loess Plateau turn “green”? Analysis of the tendency and breakpoints of the normalized difference vegetation index
Authors: Cao Zhi , Li Yurui , Liu Yansui , Chen Yufu , Wang Yongsheng
Published: November 2017

The Loess Plateau experiences the most serious soil erosion problems in China and possibly even globally. Many measures have been taken to increase the vegetation cover and to control soil erosion. Of these measures, the Grain for Green Project, launched in 1999, has been the most effective, changing the ecological and socio‐economic situation of the Plateau significantly. Using time series normalized difference vegetation index (NDVI) data from 1981 to 2013, this study analysed spatial patterns of changes in vegetation cover, detected spatial patterns of the abrupt‐change time of NDVI trends, and investigated factors that may contribute to these changes. The results showed that (a) vegetation restoration was obvious over the last decades, especially in the 2000s, and the increase in NDVI during 2000–2013 was more than 3‐times that during 1990–2000. Approximately 54.99% of the Plateau during 2000–2013 had a statistically significant increase, mainly distributing in loess hilly and gully region and loess gully region. (b) Vegetation restoration was comprehensively affected by climate change and human activities (e.g., the Grain for Green Project, urbanization and policies), and the effects of each factor varied for different regions. (c) Vegetation in most of the Plateau began to increase around 2007–2010, and 4 discrete areas with different timings of such break points were detected. The difference in the timing of break points in NDVI may be related with precipitation, reproducing tree species, management measures, and survival rate. These results imply that integrating natural and human factors is important when making effective and suitable measures and policies.
Computed tomographic assessment of autologous fat injection augmentation for vocal fold paralysis
Authors: Nishio Naoki , Fujimoto Yasushi , Hiramatsu Mariko , Maruo Takashi , Suga Kenji , Tsuzuki Hidenori , Mukoyama Nobuaki , Shimono Mariko , Toriyama Kazuhiro , Takanari Keisuke , Kamei Yuzuru , Sone Michihiko
Published: November 2017

Objective

To perform a quantitative computed tomography (CT) assessment of short‐ and long‐term outcomes of autologous fat injection augmentation in patients with unilateral vocal fold paralysis.

Study Design

Retrospective case series.

Methods

Twelve patients who had undergone autologous fat injection augmentation for unilateral vocal fold paralysis in our hospital between 2011 and 2015 were enrolled in this study. The autologous fat for injection was acquired from periumbilical subcutaneous tissue and was injected orally using a special‐purpose laryngeal injection needle. To evaluate the injected fat at the follow‐up assessments, CT was performed at several times after surgery in clinical practice. All thin‐section CT images were transferred to a workstation, and the volume of the injected fat was calculated.

Results

Patients comprised 6 men and 6 women with a mean age at the time of surgery of 62.9 years (range, 46–82 years). The actual injected fat volume was 1.1–2.5 ml (mean, 1.6 ml). In seven patients assessed by CT two days after surgery, the average residual rate of the injected fat was 63.9%. The mean residual rates of the injected fat were 30.0% at 3 months, 33.7% at 6 months, 29.2% at 12 months, and 32.0% at 24 months.

Conclusions

Although the injected fat volume decreased within the first three months and the residual rate of the injected fat was 30.0% at three months after injection, the residual fat volume remained at the same level for 24 months after injection.

Level of Evidence

4
Usefulness of ultrasound for assessing the primary tumor of hypopharyngeal carcinoma
Authors: Fukuhara Takahiro , Matsuda Eriko , Hattori Yuiko , Donishi Ryohei , Ehara Hiroaki , Fujiwara Kazunori , Takeuchi Hiromi
Published: November 2017

Objectives

To clarify the usefulness of ultrasonography for detecting hypopharyngeal cancer.

Study Design

Cross‐sectional study.

Methods

The study included 95 patients who underwent pre‐treatment ultrasonography. We evaluated the usefulness of ultrasonography for detecting primary hypopharyngeal carcinoma of each T stage and subsite, and for assessing extrahypopharyngeal invasion. Additionally, we determined the efficacy of color Doppler for evaluating primary hypopharyngeal carcinoma.

Results

The patients comprised 93 men and 2 women with a mean age of 67.5 years. The T stage (primary tumors) was T1 in 29 patients, T2 in 22, T3 in 9, and T4 in 35. Primary sites with a T stage over T3 were detected using ultrasonography in 17 patients.

Regarding primary subsites, postcricoid tumors were assessed most easily (64%), while posterior wall tumors were the most difficult to assess (25%). In 15 of 17 patients, the evaluation of extrahypopharyngeal invasion by ultrasonography matched up precisely with computed tomography findings. In addition, abnormally increased blood flow in primary hypopharyngeal cancers was recognized by color Doppler, and could be used to predict subsites.

Conclusions

Cancers at T3 and T4 hypopharyngeal primary tumors and their extrahypopharyngeal invasion were detectable using ultrasonography. Furthermore, ultrasonography was useful for assessing postcricoid tumors that were difficult to observe by flexible laryngoscopy.

Level of Evidence

4
Percutaneous gastrostomy site metastasis from head and neck tumors: A single institution case series
Authors: Metkus James S. , Cognetti David , Curry Joseph
Published: November 2017

Objectives

Head and neck cancer (HNC) patients often require percutaneous gastrostomy (PEG) tube placement due to malnutrition and dysphagia. While beneficial, PEG tube placement can cause a rare but reportable complication of metastasis of the original tumor to the gastrostomy exit site. The objectives of this case series were to present HNC patients at a single institution that developed PEG tube metastases, their subsequent treatment, and review of the literature for similar cases.

Methods

We describe three HNC patients who underwent PEG tube placement and developed metastasis at their tube site. We also describe their metastatic disease treatment and compare these cases with similar cases in the literature

Results

All three cases' initial staging were node positive and all three cases had their PEG tubes placed by the “pull” method. Two patients presented with masses at their PEG site while one patient had a site mass on surveillance positron emission topography (PET) imaging. Biopsy showed the original HNC metastasized to the gastrostomy site. Two patients were treated with surgical resection while one patient was treated with palliative chemotherapy. The “pull” method has been most associated with cases of metastasis in the literature. In the literature, risk factors for metastasis include initial tumor clinical and pathological staging.

Conclusion

PEG site metastasis should be suspected in patients with skin changes at the PEG site. “Pull” procedures may cause metastasis through physical contact with the primary tumor causing tumor seeding at the PEG site. Surgical resection of metastasis has been shown to be an effective treatment strategy for PEG site metastasis. In patients with higher stage cancers, tube insertion methods that avoid contact with the primary tumor should be considered.

Level of Evidence

NA
Non‐Rare‐Earth K2XF7:Mn4+(X = Ta, Nb): A Highly‐Efficient Narrow‐Band Red Phosphor Enabling the Application in Wide‐Color‐Gamut LCD
Authors: Lin Hang , Hu Tao , Huang Qingming , Cheng Yao , Wang Bo , Xu Ju , Wang Jiaomei , Wang Yuansheng
Published: November 2017

The advent of wide color‐gamut LED backlight technology greatly improves the user experience in visions. The bottleneck restricting progress of this technology is to develop red phosphor with satisfactory spectral features and low cost. Herein, a novel non‐rare‐earth K2XF7:Mn4+(X = Ta, Nb) was successfully designed and synthesized, exhibiting an admirable quantum efficiency of ∼93.5%, an extremely narrow FWHM of ∼2.3 nm, and a high color purity of ∼99.6%. Unlike the previously reported Mn4+activated fluorides, Mn4+in K2XF7suffers highly distorted octahedral environment in C1(or C2v) group symmetry, enabling the appearance of intense zero phonon line and distinctive vibronic transitions. Systematical high‐resolution spectroscopic analyses down to 10 K disclose the influences of strong crystal field, weak nephelauxetic effect, and intermediate electron‐phonon coupling are responsible for the peculiar spectral features of Mn4+in K2XF7. Impressively, a wide color‐gamut reaching up to 86.7% NTSC is realized, demonstrating great validity of K2XF7:Mn4+for LCD backlights. The present study not only brings a brand‐new kind of Mn4+activated host to the sight of phosphor community (the host can be extended to surges of tantalum/niobium fluorides), but also may enlighten researchers to design highly distorted environment to achieve unique spectral properties of Mn4+.
Silicon Photonics Rectangular Universal Interferometer
Authors: Perez Daniel , Gasulla Ivana , Fraile Francisco Javier , Crudgington Lee , Thomson David J. , Khokhar Ali Z. , Li Ke , Cao Wei , Mashanovich Goran Z. , Capmany Jose
Published: November 2017

Universal multiport photonic interferometers that can implement any arbitrary unitary transformation between input and output optical modes are essential to support advanced optical functions. Integrated versions of these components can be implemented by means of either a fixed triangular or a fixed rectangular arrangement of the same components. We propose the implementation of a fixed rectangular universal interferometer using a reconfigurable hexagonal waveguide mesh circuit. A suitable adaptation synthesis algorithm tailored to this mesh configuration is provided and the experimental demonstration of a rectangular multiport interferometer by means of a fabricated silicon photonics chip is reported. The 7‐hexagonal cell chip can implement 2 × 2, 3 × 3 and 4 × 4 arbitrary unitary transformations. The proposed hexagonal waveguide mesh operates in a similar way as a Field Programmable Gate Array (FPGA) in electronics. We believe that this work represents an important step‐forward towards fully programmable and integrable multiport interferometers.
Influence of Topology of Highly Porous Methacrylate Polymers on their Mechanical Properties
Authors: Paljevac Muzafera , Kotek Jiří , Jeřabek Karel , Krajnc Peter
Published: November 2017

Porous polymer monoliths are prepared using glycidyl methacrylate and methyl methacrylate as monomers, in both cases crosslinked with ethylene glycol dimethacrylate. Up to 75% porous samples are produced using either emulsion templating or bulk polymerization with porogens. In the case of emulsion templating, a cellular topology with cavities between 3.1 and 5.5 µm is observed for both monomers, while a cauliflower‐like topology is formed in the case of bulk polymerization. The influence of topology features of monoliths on the mechanical properties is studied and for both polymers a dramatic influence, on both compressive moduli and compressive strength, is found. The mechanical parameters, namely elastic modulus and compressive strength are significantly higher for emulsion templated samples.
Enhanced Thermoelectric Performance of PEDOT:PSS Films by Sequential Post‐Treatment with Formamide
Authors: Kyaw Aung Ko Ko , Yemata Temesgen A. , Wang Xizu , Lim Siew Lay , Chin Wee Shong , Hippalgaonkar Kedar , Xu Jianwei
Published: November 2017

This paper reports a series of sequential post‐treatments using a polar solvent formamide to enhance the thermoelectric performance of poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) anions (PEDOT:PSS). The electrical conductivity of PEDOT:PSS films significantly increases from 0.33 S cm−1for the pristine film to ≈2929 S cm−1for the treated film and meanwhile the Seebeck coefficient maintains as high as 17.4 µV K−1, resulting in a power factor of 88.7 µW m−1K−2. Formamide is a polar solvent with a high boiling point of 210 °C and high dielectric constant of 109, and PSS has a good solubility in it. Post‐treatment with formamide causes not only the phase segregation of PEDOT and PSS but also the removal of insulating PSS, therefore leading to the reorientation of PEDOT chains and enhancement in mobility without altering the doping level considerably. The cross‐plane thermal conductivity also reduces from 0.54 to 0.19 W m−1K−1after the post‐treatment, leading to a figure of merit (ZT) value of 0.04 at room temperature.
Regulation of Hedgehog Signaling in Cancer by Natural and Dietary Compounds
Authors: Bao Cheng , Kramata Pavel , Lee Hong Jin , Suh Nanjoo
Published: November 2017

The aberrant Hedgehog (Hh) signaling induced by mutations or overexpression of the signaling mediators has been implicated in cancer, associated with processes including inflammation, tumor cell growth, invasion, and metastasis, as well as cancer stemness. Small molecules targeting the regulatory components of the Hh signaling pathway, especially Smoothened (Smo), have been developed for the treatment of cancer. However, acquired resistance to a Smo inhibitor vismodegib observed in clinical trials suggests that other Hh signaling components need to be explored as potential anticancer targets. Natural and dietary compounds provide a resource for the development of potent agents affecting intracellular signaling cascades, and numerous studies have been conducted to evaluate the efficacy of natural products in targeting the Hh signaling pathway. In this review, we summarize the role of Hh signaling in tumorigenesis, discuss results from recent studies investigating the effect of natural products and dietary components on Hh signaling in cancer, and provide insight on novel small molecules as potential Hh signaling inhibitors.
The capacity formulation of the capacitated edge activation problem
Authors: Mattia Sara
Published: November 2017

Given a capacitated network, the Capacitated Edge Activation problem consists of choosing the edges to be activated to ensure the routing of a set of demands. We focus on capacity formulations of the problem, that is, formulations including only design variables, whereas variables corresponding to the routes are projected out. First, we investigate the combinatorial properties of the problem to derive a capacity formulation both for splittable flows (the routes are unrestricted) and for unsplittable ones (each demand must be routed on a single path). Then, we study the corresponding polyhedron, identifying valid and facet‐defining inequalities. Finally, we develop a branch‐and‐cut algorithm and present computational results.
Computational measurements of stress fields from digital images
Authors: Réthoré Julien , Leygue Adrien , Coret Michel , Stainier Laurent , Verron Erwan
Published: November 2017

Since the pioneering works on digital image correlation, a huge effort has been devoted to the elaboration of strategies coupling measurements with numerical simulations. The main issue achieved with such coupling is the identification of constitutive law parameters from experimental configurations yielding heterogeneous strain/stress fields. The main limitation of this framework is that a constitutive law is to be postulated, what sometimes reveals far from being straightforward. To circumvent this limitation, a methodology is proposed to build a parametric description not only of the displacement field for digital image correlation but also of the local stress. With no assumption on the constitutive relation, the method allows for estimating displacement, strain, and stress fields. The ability of the method is illustrated for different situations.
A Two‐Photon Ratiometric Fluorescent Probe for Imaging of Hydrogen Peroxide Levels in Rat Organ Tissues
Authors: Lim Chang Su , Cho Myoung Ki , Park Mi Yeon , Kim Hwan Myung
Published: November 2017

Hydrogen peroxide (H2O2) is important in the regulation of a variety of biological processes and is involved in various diseases. Quantitative measurement of H2O2 levels at the subcellular level is important for understanding its positive and negative effects on biological processes. Herein, a two‐photon ratiometric fluorescent probe (SHP‐Cyto) with a boronate‐based carbamate leaving group as the H2O2 reactive trigger and 6‐(benzo[d]thiazol‐2′‐yl)‐2‐(N,N‐dimethylamino) naphthalene (BTDAN) as the fluorophore was synthesized and examined for its ability to detect cytosolic H2O2 in situ. This probe, based on the specific reaction between boronate and H2O2, displayed a fluorescent color change (455 to 528 nm) in response to H2O2 in the presence of diverse reactive oxygen species in a physiological medium. In addition, ratiometric two‐photon microscopy (TPM) images with SHP‐Cyto revealed that H2O2 levels gradually increased from brain to kidney, skin, heart, lung, and then liver tissues. SHP‐Cyto was successfully applied to the imaging of endogenously produced cytosolic H2O2 levels in live cells and various rat organs by using TPM.
Should embryos with autosomal monosomy by preimplantation genetic testing for aneuploidy be transferred?: Implications for embryo selection from a systematic literature review of autosomal monosomy survivors
Authors: Bunnell M.E. , Wilkins‐Haug L. , Reiss R.
Published: November 2017

Objective

To review the literature for survival and phenotypes of liveborns with autosomal monosomy to inform decisions regarding transfer of in vitro fertilization‐derived embryos reported as monosomic on preimplantation genetic testing for aneuploidy (PGT‐A).

Method

Ovid‐Medline and EMBASE were systematically searched to identify published case reports of liveborn individuals with autosomal monosomy, full or mosaic, for a whole chromosome.

Results

Fifty‐three reports describing 56 individuals with autosomal monosomy met the selection criteria: 1 case each of monosomy 14 and 16, 3 each for monosomy 15 and 18, 1 for group “E”, 5 for monosomy 20, 24 for monosomy 21, 7 for monosomy 22, and eleven for a “G” group chromosome. There were no reports with monosomy for the larger chromosomes 1 through 13, nor for chromosomes 17 or 19, autosomes with highest gene density. Most reported individuals had severe handicaps and died in infancy with some surviving longer.

Conclusion

Given potential for survival of handicapped individuals with autosomal monosomy for chromosomes 14, 15, 16, 18, 20, 21, and 22, low priority should be given to transfer of embryos apparently monosomic for these chromosomes. Couples electing transfer of monosomic embryos should consider amniocentesis for ongoing pregnancies but should be informed of its limitations.
Enhancing the molecular cooperativity of polyvinyl butyral using liquid additives
Authors: Carini Giovanni , Carini Giuseppe , D'Angelo Giovanna , Federico Mauro , Marco Gaetano Di , Bartolotta Antonino
Published: November 2017

The specific role of acetonitrile and methoxypropionitrile, as accelerators of the relaxation dynamics of polyvinyl butyral (PVB), was investigated in polymer/additive mixtures with a saturation liquid content. The aim was to improve the ionic mobility of PVB‐based solid electrolytes to be used in solid dye‐sensitized solar cells. Mechanical and dielectric relaxation measurements between 120 K and 380 K revealed that the α‐relaxation observed above 330 K in dry‐PVB is shifted quite below room temperature in PVB/additives. Both the additives cause a growing intermolecular cooperativity, the sub‐glass β‐relaxation exhibiting a strength enhanced by a factor 3 and a frequency factor which increases from 1015 s−1 to 1021 s−1. This discloses an activation entropy as high as 165.7 J/K mol in comparison to 40.8 J/K mol in dry‐PVB. It is suggested the existence of cooperative transitions, mainly driven by bridges formed through additive molecules, which influence both short‐ and long‐scale segmental motions and also favor the ion dynamics in PVB/additive/electrolyte systems. The room temperature ionic conductivity σrt exhibits large changes from 6.4*10−14 S/m in dry PVB, through 1.5*10−8 S/m in PVB/LiI, to 2.45*10−5 S/m in PVB/MPN/LiI. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 340–346
The random connection model: Connectivity, edge lengths, and degree distributions
Authors: Iyer Srikanth K.
Published: November 2017

Consider the random graph whose vertex set is a Poisson point process of intensity n on . Any two vertices are connected by an edge with probability , independently of all other edges, and independent of the other points of . d is the toroidal metric, r > 0 and is non‐increasing and . Under suitable conditions on g, almost surely, the critical parameter Mn for which does not have any isolated nodes satisfies . Let , and θ be the volume of the unit ball in . Then for all , is connected with probability approaching one as . The bound can be seen to be tight for the usual random geometric graph obtained by setting . We also prove some useful results on the asymptotic behavior of the length of the edges and the degree distribution in the connectivity regime. The results in this paper work for connection functions g that are not necessarily compactly supported but satisfy .
Preclinical Evaluation and Optimization of a Cell Therapy Using Human Cord Blood-Derived Endothelial Colony-Forming Cells for Ischemic Retinopathies
Authors: Reid Emma , Guduric-Fuchs Jasenka , O'Neill Christina L. , Allen Lynsey-Dawn , Chambers Sarah E. J. , Stitt Alan W. , Medina Reinhold J.
Published: November 2017

Cell therapy using endothelial progenitors holds promise for vascular repair in ischemic retinopathies. Using a well-defined subpopulation of human cord blood-derived endothelial progenitors known as endothelial colony-forming cells (ECFCs), we have evaluated essential requirements for further development of this cell therapy targeting the ischemic retina, including dose response, delivery route, and toxicity. First, to evaluate therapeutic efficacy relating to cell dose, ECFCs were injected into the vitreous of mice with oxygen-induced retinopathy. Using angiography and histology, we found that intravitreal delivery of low dose (1 × 103) ECFCs was as effective as higher cell doses (1 × 104, 1 × 105) in promoting vascular repair. Second, injection into the common carotid artery was tested as an alternative, systemic delivery route. Intracarotid ECFC delivery conferred therapeutic benefit which was comparable to intravitreal delivery using the same ECFC dose (1 × 105), although there were fewer human cells observed in the retinal vasculature following systemic delivery. Third, cell immunogenicity was evaluated by injecting ECFCs into the vitreous of healthy adult mice. Assessment of murine ocular tissues identified injected cells in the vitreous, while demonstrating integrity of the host retina. In addition, ECFCs did not invade into the retina, but remained in the vitreous, where they eventually underwent cell death within 3 days of delivery without evoking an inflammatory response. Human specific Alu sequences were not found in healthy mouse retinas after 3 days of ECFC delivery. These findings provide supportive preclinical evidence for the development of ECFCs as an efficacious cell product for ischemic retinopathies.
A state transition framework for patient‐level modeling of engagement and retention in HIV care using longitudinal cohort data
Authors: Lee Hana , Hogan Joseph W. , Genberg Becky L. , Wu Xiaotian K. , Musick Beverly S. , Mwangi Ann , Braitstein Paula
Published: November 2017

The human immunodeficiency virus (HIV) care cascade is a conceptual model used to outline the benchmarks that reflects effectiveness of HIV care in the whole HIV care continuum. The models can be used to identify barriers contributing to poor outcomes along each benchmark in the cascade such as disengagement from care or death. Recently, the HIV care cascade has been widely applied to monitor progress towards HIV prevention and care goals in an attempt to develop strategies to improve health outcomes along the care continuum. Yet, there are challenges in quantifying successes and gaps in HIV care using the cascade models that are partly due to the lack of analytic approaches. The availability of large cohort data presents an opportunity to develop a coherent statistical framework for analysis of the HIV care cascade. Motivated by data from the Academic Model Providing Access to Healthcare, which has provided HIV care to nearly 200,000 individuals in Western Kenya since 2001, we developed a state transition framework that can characterize patient‐level movements through the multiple stages of the HIV care cascade. We describe how to transform large observational data into an analyzable format. We then illustrate the state transition framework via multistate modeling to quantify dynamics in retention aspects of care. The proposed modeling approach identifies the transition probabilities of moving through each stage in the care cascade. In addition, this approach allows regression‐based estimation to characterize effects of (time‐varying) predictors of within and between state transitions such as retention, disengagement, re‐entry into care, transfer‐out, and mortality. Copyright © 2017 John Wiley & Sons, Ltd.
Internal pilot design for balanced repeated measures
Authors: Zhang Xinrui , Muller Keith E. , Goodenow Maureen M. , Chi Yueh‐Yun
Published: November 2017

Repeated measures are common in clinical trials and epidemiological studies. Designing studies with repeated measures requires reasonably accurate specifications of the variances and correlations to select an appropriate sample size. Underspecifying the variances leads to a sample size that is inadequate to detect a meaningful scientific difference, while overspecifying the variances results in an unnecessarily large sample size. Both lead to wasting resources and placing study participants in unwarranted risk. An internal pilot design allows sample size recalculation based on estimates of the nuisance parameters in the covariance matrix. We provide the theoretical results that account for the stochastic nature of the final sample size in a common class of linear mixed models. The results are useful for designing studies with repeated measures and balanced design. Simulations examine the impact of misspecification of the covariance matrix and demonstrate the accuracy of the approximations in controlling the type I error rate and achieving the target power. The proposed methods are applied to a longitudinal study assessing early antiretroviral therapy for youth living with HIV.
Exponential decay for binary time‐varying covariates in Cox models
Authors: Keown‐Stoneman Charles Donald George , Horrocks Julie , Darlington Gerarda
Published: November 2017

Cox models are commonly used in the analysis of time to event data. One advantage of Cox models is the ability to include time‐varying covariates, often a binary covariate that codes for the occurrence of an event that affects an individual subject. A common assumption in this case is that the effect of the event on the outcome of interest is constant and permanent for each subject. In this paper, we propose a modification to the Cox model to allow the influence of an event to exponentially decay over time. Methods for generating data using the inverse cumulative density function for the proposed model are developed. Likelihood ratio tests and AIC are investigated as methods for comparing the proposed model to the commonly used permanent exposure model. A simulation study is performed, and 3 different data sets are presented as examples.
Five criteria for using a surrogate endpoint to predict treatment effect based on data from multiple previous trials
Authors: Baker Stuart G.
Published: November 2017

A surrogate endpoint in a randomized clinical trial is an endpoint that occurs after randomization and before the true, clinically meaningful, endpoint that yields conclusions about the effect of treatment on true endpoint. A surrogate endpoint can accelerate the evaluation of new treatments but at the risk of misleading conclusions. Therefore, criteria are needed for deciding whether to use a surrogate endpoint in a new trial. For the meta‐analytic setting of multiple previous trials, each with the same pair of surrogate and true endpoints, this article formulates 5 criteria for using a surrogate endpoint in a new trial to predict the effect of treatment on the true endpoint in the new trial. The first 2 criteria, which are easily computed from a zero‐intercept linear random effects model, involve statistical considerations: an acceptable sample size multiplier and an acceptable prediction separation score. The remaining 3 criteria involve clinical and biological considerations: similarity of biological mechanisms of treatments between the new trial and previous trials, similarity of secondary treatments following the surrogate endpoint between the new trial and previous trials, and a negligible risk of harmful side effects arising after the observation of the surrogate endpoint in the new trial. These 5 criteria constitute an appropriately high bar for using a surrogate endpoint to make a definitive treatment recommendation.
1,3,5‐Oxadiazine Framework by Oxygen vs. Nitrogen Trapping of an N‐Acyliminium Ion Derived from N,O‐bis‐TMS Pyroglutamic Acid
Authors: Ghinet Alina , Abuhaie Cristina‐Maria , Homerin Germain , Marzag Hamid , Dubois Joëlle , Lipka Emmanuelle , Rigo Benoît , Daïch Adam
Published: November 2017

We report that the reaction of N,O‐bis‐TMS pyroglutamic acid with aldehydes, under basic or acid catalysis leads to O‐bis‐TMS adducts. Treatment of these N,O‐acetals by TfOH affords azalactones or N,N′‐substituted methylene‐bis‐pyroglutamic acids from the trapping of N‐acyliminium species, respectively, with oxygen or nitrogen atom intramolecularly versus intermolecularly. Anodic oxidation of the amido acids, followed by diastereoselective oxa‐cyclisation of new N‐acyliminium salts, provides exclusively fused meso‐1,3,5‐oxadiazines with the stereochemistry secured by X‐ray analysis. The reactivity of these skeletons under both alkaline and acid conditions was also envisioned and discussed.
Glycerol: A Promising Benign Solvent for Catalyst Free One‐Pot Multi‐Component Synthesis of Pyrano[2,3‐c]pyrazoles and Tetrahydro‐benzo[b]pyrans at Ambient Temperature
Authors: Abdel Hamid Afaf , Abd‐Elmonem Mohamed , Hayallah Alaa M. , Abo Elsoud Fatma A. , Sadek Kamal U.
Published: November 2017

A simple and efficient synthesis of 6‐amino‐5‐cyano‐4‐aryl‐1,4‐dihydropyrano[2, 3‐c]pyrazoles and 2‐amino‐3‐cyano‐4‐aryl‐7,7‐dimethyl‐5,6,7,8‐tetrahydrobenzo[b]pyrans has been developed that involves a four‐component reaction of aromatic aldehydes, malononitrile, hydrazine hydrate or phenyl hydrazine and 1,3‐dicarbonyl compounds using glycerol as both solvent and catalyst at ambient temperature. Several advantages have been achieved such as high yields, facile conducting reactants or working up products, high Eco Scale, atom economy and the absence of toxic or hazardous catalysts or solvents.
Template‐Free Self‐Assembly of Dimeric Dicarbocyanine Dyes
Authors: Patlolla Prathap Reddy , Mallajosyula Sairam S. , Datta Bhaskar
Published: November 2017

Symmetrical dicarbocyanine dyes are known to cooperatively assemble on DNA templates. With the goal of developing dyes that are capable of template‐free self‐assembly, two N‐linked dimeric benzothiazole containing pentamethine cyanine dyes have been synthesized. UV‐visible spectroscopy of the dimeric dyes reveals very strong propensities for self‐assembly unlike their monomeric dye counterparts. The N‐propyl linked dye exhibits pronounced H‐aggregation at micromolar dye concentrations with the absorption maxima blue‐shifted by nearly 200 nm. In contrast, an N‐hexyl linked dye preferentially folds into H‐dimers. Similar aggregates of the monomeric dicarbocyanine dyes are known to be observed at much higher dye concentrations or in presence of suitable templates such as DNA molecules. The aggregate species of the dimeric dyes are identified based on shifts in their absorbance maxima and quenched fluorescence. The calculated electronic structure of the dimeric dyes supports their observed aggregation behaviour. Further, introduction of DNA molecules with AT‐tracts leads to transformation of the spontaneously formed dimeric dye H‐aggregates and H‐dimers into DNA‐bound dye species.
Porous Carbon Nanosheets with Abundant Oxygen Functionalities Derived from Phoenix Seeds for High‐Performance Supercapacitor
Authors: Shen Yu , Qu Tingting , Xiang Kun , Zhang Yu , Tian Zhengfang , Xie Mingjiang , Guo Xuefeng
Published: November 2017

Biomass‐derived porous carbon with abundant electro‐active oxygen functionalities was prepared by controlled pyrolysis and KOH activation of phoenix seeds, in which KOH not only acts as activation reagent constructing porous structure, but also serves as adjustor tuning the C/O ratio of the final carbon products. The obtained porous activated carbon nanosheet (PACN) possesses nanosheet morphology with nanoporous structure, large surface area (1166 m2/g) and high oxygen content of 10.2 at. %. As electrode for supercapacitor in 2.0 M H2SO4 electrolyte, the PACN achieves a high capacitance of 376 F/g at current density of 0.5 A/g, good rate capability (230 F/g at 20.0 A/g) and an excellent cycling stability with 99% capacitance retention over 10000 cycles, which can be attributed to the large surface area and rich electro‐active oxygenic functionalities. The symmetric supercapacitor with PACN exhibits a superior energy density of 5.9 Wh/kg at 3.5 kW/kg. The present work highlights the controlled pyrolysis and KOH activation strategy as a facile approach to utilize a potential biomass resource for low‐cost and high‐performance electrochemical capacitors.
Photoinduced Interfacial Electron Transfer in 2,2’‐Bipyridyl Iron(III) Complex‐TiO2 Nanoparticles in Aqueous Medium
Authors: Ganeshraja Ayyakannu Sundaram , Yang Minghui , Xu Wei , Anbalagan Krishnamoorthy , Wang Junhu
Published: November 2017

The near‐UV and visible light induced interfacial electron transfer (IFET) process between aqueous solution of [Fe(bipy)2Cl2][FeCl4] complex and TiO2 NPs has been proved at first time and the photochemical products were mainly characterized by electronic absorption, Fe K‐edge X‐ray absorption fine structure, electron paramagnetic resonance and 57Fe Mössbauer spectroscopic method. This study makes in comprehending for the combination of semiconductor NPs and metal complex, in‐particularly ionic salt like complex has potential in environmental friendly synthesis and remediation process.