bluuebunny/crossref_metadata_2025 huggingface dataset:
Telophase correction refines division orientation in stratified epithelia
Authors: Lough Kendall J , Byrd Kevin M , Descovich Carlos P , Spitzer Danielle C , Bergman Abby J , Beaudoin Gerard MJ , Reichardt Louis F , Williams Scott E
Published: December 2019

During organogenesis, precise control of spindle orientation balances proliferation and differentiation. In the developing murine epidermis, planar and perpendicular divisions yield symmetric and asymmetric fate outcomes, respectively. Classically, division axis specification involves centrosome migration and spindle rotation, events occurring early in mitosis. Here, we identify a novel orientation mechanism which corrects erroneous anaphase orientations during telophase. The directionality of reorientation correlates with the maintenance or loss of basal contact by the apical daughter. While the scaffolding protein LGN is known to determine initial spindle positioning, we show that LGN also functions during telophase to reorient oblique divisions toward perpendicular. The fidelity of telophase correction also relies on the tension-sensitive adherens junction proteins vinculin, α-E-catenin, and afadin. Failure of this corrective mechanism impacts tissue architecture, as persistent oblique divisions induce precocious, sustained differentiation. The division orientation plasticity provided by telophase correction may enable progenitors to adapt to local tissue needs.
Uncovering the secret life of Rho GTPases
Authors: Perry Jenna A , Maddox Amy Shaub
Published: December 2019

New methods to directly visualize Rho GTPases reveal how a protein called RhoGDI regulates the activity of these 'molecular switches' at the plasma membrane.
From Meow to ROAR: Expanding Open Access Repository Services at the University of Houston Libraries
Authors: Wu Annie , Davis-Van Atta Taylor , Thompson Santi , Scott Bethany , Washington Anne , Liu Xiping
Published: December 2019

INTRODUCTION The rapidly changing scholarly communication ecosystem is placing a growing premium on research data and scholarship that is openly available. It also places a growing pressure on universities and research organizations to expand their publishing infrastructures and related services. DESCRIPTION OF PROGRAM To embrace the change and meet local demands, University of Houston (UH) Libraries formed a cross-departmental open access implementation team in 2017 to expand our open access repository services to accommodate a broad range of research products beyond electronic theses and dissertations (ETDs). The result of this effort was the Cougar Research Open Access Repositories (Cougar ROAR), a rebranded and expanded portal to the UH Institutional Repository, and the UH Dataverse, which disseminates the full range of scholarly outputs generated at the University of Houston. This article describes the team’s phased activities, including internal preparation, a campus pilot, rebranding, and a robust outreach program. It also details the team’s specific tasks, such as building the Cougar ROAR portal, developing ROAR policies and guidelines, enhancing institutional repository functionality, conducting campus promotional activities, and piloting and scaling a campus-wide open access program. NEXT STEPS Based on the pilot project findings and the resulting recommendations, the team outlined key next steps for sustainability of the UH Libraries’ open access services: continuation of the campus CV service, establishment of campus-wide OA policy, further promotion of Cougar ROAR and assessment of OA programs and services, and investment in long-term storage and preservation of scholarly output in Cougar ROAR.
Vegetation dynamic analysis based on multisource remote sensing data in the east margin of the Qinghai-Tibet Plateau, China
Authors: Wang Haijun , Peng Peihao , Kong Xiangdong , Zhang Tingbin , Yi Guihua
Published: December 2019

This study focuses on the vegetation dynamic caused by global environmental change in the eastern margin of the Qinghai-Tibet Plateau (EMQTP). The Qinghai–Tibet Plateau (QTP) is one of the most sensitive areas responding to global environmental change, particularly global climate change, and has been recognized as a hotspot for coupled studies on changes in global terrestrial ecosystems and global climates. An important component of terrestrial ecosystems, vegetation dynamic has become a key issue in global environmental change, and numerous case studies have been conducted on vegetation dynamic trends using multi-source data and multi-scale methods across different study periods. The EMQTP is regarded as a transitional area located between the QTP and the Sichuan basin, and has special geographical and climatic conditions. Although this area is ecologically fragile and sensitive to climate change, few studies about vegetation dynamics have been carried out in this area. Thus, in this study, we used long-term series datasets of GIMMS 3g NDVI and VGT/PROBA-V NDVI to analyze the vegetation dynamics and phenological changes from 1982 to 2018. Validation was performed based on Landsat NDVI and Vegetation Index & Phenology (VIP) data. The results reveal that the year 1998 was a vital turning point in the start of growing season (SGS) in vegetation ecosystems. Before this turning point, the SGS had an average slope of 9.2 days/decade, and after, the average slope was 3.9 days/decade. The length of growing season (LGS) was slightly prolonged between 1982 to 2015. Additionally, the largest national alpine wetland grassland experienced significant vegetation degradation; in autumn, the degraded area accounted for 63.4%. Vegetation degradation had also appeared in the arid valleys of the Yalong River and the Jinsha River. Through validation analysis, we found that the main causes of vegetation degradation are the natural degradation of wetland grassland and human activities, specifically agricultural development and residential area expansion.
Effects of NPK Fertiliser (15-15-15) on the Growth Performance of Three Arable Crops Grown on Degraded Kaolin Mined Soil in Abia State, Southeast Nigeria
Authors: Igwe C. E. , Azorji J. N. , Nwachukwu M. O.
Published: December 2019

Experiments were carried out in the Nursery of the Department of Forestry and Environmental Management, the Michael Okpara University of Agriculture, Umudike in Abia State during 2016 and 2017 cropping seasons to determine  the effect of NPK fertilizer on the growth performance of three selected crops, Zea mays, Abelmoschus esculentus and Vigna unguiculata grown on a derelict kaolin mined soil. The experiment comprised of treatment pots which has three rates of fertilizer on the kaolin soil each (kaolin soil +NPK (40 kg), kaolin soil + NPK (30 kg) and kaolin soil + NPK (20 kg) kaolin soil with zero treatment (Control 2) and a control 1(un-mined) soil, it was replicated three in Complete Randomized Design (CRD). Parameters assessed include Plant height (cm) and the number of leaves weekly for six (6) weeks. Data were analysed using ANOVA at p< 0.05. The result obtained showed that growth performance of the test crops was positively affected by NPK treatment based on the quantity applied with the highest recorded height (16.50) and the number of the leaf (11.27) in Kaolin mined soil combined with 40 kg of fertilizer when compared with the control. Plant height obtained with various fertilizer treatments were in the order: 16.50>15.99>14.65 and 11.27>10.20>9.01 for the number of leaves. The result of the macro element levels in the plants showed that the nutrient uptake and accumulation were enhanced by both NPK fertilizer and the quantity added with the highest level of nutrient on the plants obtained in Kaolin soil combined with 40kg of NPK fertilizer. The study showed that kaolin mined degraded soil can be put into good use with the appropriate concentration of fertilizer treatment, thus putting more degraded land under agricultural production and ensuring food security is developing country like Nigeria. The study further suggests a sensitization program for farmers on the appropriate concentration of inorganic fertilizer to be applied to their farmers to avoid pollution.
Impact of Irradiated Compost on Growth and Nutritional Status of Valencia Orange Grown in the Desert Areas
Authors: Mohamed Farid A. , Ahmed Mohamed Farouk
Published: December 2019

Aims: To evaluate the effect of compost application whether irradiated or not in addition to recommended mineral fertilization on growth and nutritional status of Valencia orange trees.

Study Design: The design of the study is a randomized complete block design. The study was done on five-years-old Valencia orange grown in a loamy sand soil.

Place and Duration of Study: The study was conducted in El-Shrouk yard -Cairo-Alexandria Desert Road through five successive seasons 2014, 2015, 2016, 2017 and 2018. Compost irradiation was done at the National Centre for Radiation Research and Technology, Atomic Energy Authority.

Methodology: In addition to mineral fertilization, four main treatments were applied to Valencia orange trees, T1 three years application of non-irradiated compost, T2 four years application of non- irradiated compost, T3 and T4 similar to T1 and T2 while irradiated compost was applied. Shoot length and thickness, leaf number and area were calculated. Leaf N, P and K% as well as Fe, Mn, Zn and total chlorophyll content were measured.

Results: Data revealed that application of compost especially irradiated form in combination with chemical fertilizers has a positive effect on vegetative growth of Valencia orange trees in addition to leaf content of nitrogen, phosphorus, potassium, iron, manganese, zinc and total chlorophyll. Four years application of compost regardless irradiation was superior to three years application. Combination of irradiated compost and four years application gave the highest values for the previously mentioned parameters.

Conclusion: Addition of compost to chemical fertilizers improved the vegetative growth and nutritional status of Valencia orange trees. Irradiation of compost increased its efficiency that might reduce the time of application. Also, using compost, particularly in the newly reclaimed soil, greatly increase water and mineral fertilizers use efficiency, which in turn lead to saving in irrigation water and fertilization nutrients.
Effect of Centrifugal Force on a Porous Anisotropic Medium in Rotation, Saturated by a Non-Newtonian Fluid
Authors: Edmond Claude Vodounnou , Clément Ahouannou , Guy Clarence Semassou , Emile Sanya A. , Gérard Dègan
Published: December 2019

The present study deals with the linear stability of an anisotropic porous medium in rotation, saturated by a non-Newtonian fluid in a rectangular cavity heated on the side, subjected to the effect of the centrifugal force. The state of marginal stability is established by determining the critical Rayleigh number and the critical wave number. We have observed the effect of the parameters  and  of the anisotropy on the convection threshold.
Evaluation of Pollen and Chemical Composition of Honey Samples Sourced from Open Markets in Anambra State, Nigeria to Ascertain their Authenticity
Authors: Chukwuemeka Njokuocha, Reginald
Published: December 2019

Aims: To ascertain the predominant honey plants that served as major sources of nectar and or pollen to the honeybees and to determine the quantitative presence of some physico-chemical components of the honey samples.

Study Design: The honey samples were collected from the various locations based on purposive sampling.

Place and Duration of Study: The samples were collected from seven towns in three Local Government Areas of Anambra State as follows; Ukpor, Usumenyi and Ezinifite (Nnewi South LGA), Nnokwa, Alor and Nnobi (Idemmili South LGA) and Ezinifite (Aguata LGA) between January and April, 2013.

Methodology: The honey samples were dissolved in warm (40ºC) acidified water and subsequently subjected to acetolysis treatment. The recovered residues were suspended in glycerol-alcohol mixture in vials from where samples were collected for routine pollen count and identification. The chemical analysis was carried out according to the analysis of the Association of Official Analytical Chemists with four replicates. The pollen data were converted to percentage, while data from chemical parameters were converted to mean and standard deviation.

Results: A total of 67 pollen types belonging to 39 families were identified. The honey samples were grouped into two based on the botanical origin: three monofloral and four polyfloral honeys. The predominant honey plants include Hymenocardia acida, Combtretaceae/Melastomataceae, Lannea sp., Alchornea cordifolia and Phyllanthus muellerianus. The chemical analysis showed that the values of all the parameters (moisture, pH, Sucrose, Protein, Hydroxymethyl furfural, etc) tested were within the acceptable limits of international honey standard. However, the sum of glucose and fructose in three honey samples did not meet the 60g/100g recommended as minimum limit for blossom honeys.

Conclusion: The chemical analysis showed that the honey samples contained acceptable standard concentrations of all the physicochemical parameters (such as HMF, protein, moisture, sucrose, etc.)  tested with exception of the sum of glucose and fructose which did not meet the standard in some samples. The predominant honey plants that served as sources of nectar and pollen in the to the bees include Hymenocardia acida, Lannea sp., Phyllanthus muellerianus and members of the Combretaceae/Melastomataceae families.
Revisiting the Dichotomy between Abusive Supervision and Work Performance of Subordinates in Private Organizations in Kenya: An Empirical Search for Correspondence between Theory and Practice
Authors: Fred Ssemugenyi , Asumwa Agustine Amboka , Sophia Kazibwe
Published: December 2019

This systematic and empirical review attempted to expand the frontiers of knowledge on abusive supervision against employee performance using private sector as a case sample. Using no mediating model between X and Y, the study focused on the assumed and observable linearity between the two variables under investigation whilst using available quantitative and qualitative data as point of reference. Hypothetically, it is assumed that, abusive supervision has a negative correlation with employee performance across organization. This kind of reasoning is guided by observable longitudinal data, feelings and opinions drawn from various categories of individuals over time. Important to note, is the fact that, these observations are in conflict with many research works and reports whose conclusions seem to suggest that abusive supervision has a direct positive causal impact on employee performance. This empirical review is borne out of this contradiction as an attempt to contribute to the ongoing debate and systematically direct reasoning to the desired end. A statistically selected sample of 80 respondents from 101 total population was drawn from 10 private organizations across Kenya for quantitative data and a team of key informants (10) one from each organization was selected for interviews. A mixed method approach was adopted which gave birth to descriptive statistics and thematic approach for analysis. A casual path linking the supervisor mindfulness, supervisor hostility, supervisor attitudes and organizational leadership structures was established. Supervisor hostility and attitudes negatively affected employee performance in the private sector organizations whilst supervisor mindfulness and organizational leadership structures positively affected employee performance in the same context. Important to note is that, although the associations between perceptions of abusive supervision and employee performance appear to be universally negative, the magnitude of the relationship between perceptions of abusive supervision and employee performance varies according to the study design, context, culture and timing.  Great need is sought to continuously harmonize the synergy between theory and practice for the future of the practitioners rests entirely on this evaluation.
Frequency, Harmfulness and Vulnerability (FHV) Multicriteria Method for Integrated Analysis of Illegal Exploitations and Strategic Participatory Management of Protected Areas in Africa
Authors: Elysée Ntiranyibagira , Thacienne Uwiringiyimana , Concorde Nsengumuremyi , Andrew Kibogo , Fabien Muhirwa , Léonidas Maniraho , Aloys Twagirumukiza , Innocent Ngiruwonsanga
Published: December 2019

In Africa, protected areas are facing hudge illegal exploitations and accelerated degradation. Illegal exploitations are interesting indicators of local socio-economic needs and hostility of populations to conservation activities. The study aimed to develop a specific method for the analysis of illegal exploitations and the promotion of successful participatory management. Basically, the Multicriteria method used to determine the impact and the gravity of illegal exploitations relies on three criteria based on offenses themselves and affected resources. The method combines statistical analysis of management data using ANOVA and χ² tests, field observations and semi-structured interviews for validation. For the tested Rusizi national Park, the findings showed that the number of supervised exploitations increased from 1988 to 2015 while the number of supervised operators is limited and highly fluctuating between resources and periods. The public integration ratio is 8 0/000 and corresponds to 61 supervised operators of which 84% are involved in vegetal resources exploitations. In total, 10 illegal exploitations whose impact values range from 1 to 20 and belong to very high and high impact classes were reported.  Average, 651 cases of which 71% cover direct cuts of vegetation were reported annually. Statistically, the most damaging illegal exploitations are made of tree and vegetation cuts, cattle grazing and fishing. Illegal exploitations are seasonal and more important in dry season than in rainy season. They are more important in Delta sector than in Palmeraie sector. The shift from gracious exploitations to lucrative operations, over-taxation of supervised exploitations, low ratio of public integration, political conflicts and unarmed protection contributed to increase and strengthen significantly illegal exploitations. Ultimately, the results revealed the limits of participatory management on illegal exploitations. Consequently, the success of participatory management in Rusizi national Park requires strategic and concerted development projects, more responsive regulatory measures and relevant partnerships with peripheral village.
The Effect of Vitamin B6 on Reducing the Number and the Size of Breast Cysts and the Amount of Recurrence after Aspiration in Women
Authors: Soltany Setareh , Reza Hemmati Hamid , Alavy Toussy Jafar , Alavi Toosi Parisa
Published: December 2019

Introduction: Palpable breast lumps are one of the most prevalent breast problems in women who visit a doctor. Most of these lumps are benign, and many of these benign lumps, have cystic nature. One of the suggested treatments for breast cyst is vitamin B6 intake. So, this study aimed to determine the effect of vitamin B6 on reducing the number and the size of breast cysts and reducing the amount of recurrence after aspiration.

Materials and Methods: This study is a double-blind randomized clinical trial. Patients simply divided into two groups randomly, intervention group (receiving 150 mg vitamin B6 twice a day for two months) and control group (placebo). After data collection, the database produced, and information came in by SPSS-22 software. Descriptive results extracted in the form of tables and graphs. In all cases was used α=0.05.

Results: At the end of the study, 65 patients (34 people in the intervention group, and 31 people in the control group) studied. At the end of the survey in the non-palpable cysts, was observed a significant decrease in the number and the size of breast cysts in each group receiving vitamin B6 or placebo. Still, the difference was not significant in comparing the two groups. 19 patients (2.29%) had palpable cysts that aspiration performed in all cases. After the study period, no recurrence of cysts observed in any of the intervention and control groups.

Conclusion: The study showed that vitamin B6 had no effect on reducing the size and the number of non-palpable breast cysts and prevent recurrence of palpable cysts after aspiration.
Liquid–liquid phase separation of the Golgi matrix protein GM130
Authors: Rebane Aleksander A. , Ziltener Pascal , LaMonica Lauren C. , Bauer Antonia H. , Zheng Hong , López‐Montero Iván , Pincet Frederic , Rothman James E. , Ernst Andreas M.
Published: December 2019

Golgins are an abundant class of peripheral membrane proteins of the Golgi. These very long (50–400 nm) rod‐like proteins initially capture cognate transport vesicles, thus enabling subsequent SNARE‐mediated membrane fusion. Here, we explore the hypothesis that in addition to serving as vesicle tethers, Golgins may also possess the capacity to phase separate and, thereby, contribute to the internal organization of the Golgi. GM130 is the most abundant Golgin at the cis Golgi. Remarkably, overexpressed GM130 forms liquid droplets in cells analogous to those described for numerous intrinsically disordered proteins with low complexity sequences, even though GM130 is neither low in complexity nor intrinsically disordered. Virtually pure recombinant GM130 also phase‐separates into dynamic, liquid‐like droplets in close to physiological buffers and at concentrations similar to its estimated local concentration at the cis Golgi.
Pyruvate kinase M2 represses thermogenic gene expression in brown adipocytes
Authors: Isidor Marie S. , Winther Sally , Markussen Lasse K. , Basse Astrid L. , Quistorff Bjørn , Nedergaard Jan , Emanuelli Brice , Hansen Jacob B.
Published: December 2019

Utilizing the thermogenic capacity of brown adipose tissue is a potential anti‐obesity strategy; therefore, the mechanisms controlling expression of thermogenesis‐related genes are of interest. Pyruvate kinase (PK) catalyzes the last step of glycolysis and exists as four isoenzymes: PK, liver, PK, red blood cell, PK, muscle (PKM1 and PKM2). PKM2 has both glycolytic and nuclear functions. Here, we report that PKM2 is enriched in brown adipose compared with white adipose tissue. Specific knockdown of PKM2 in mature brown adipocytes demonstrates that silencing of PKM2 does not lead to a decrease in PK activity, but causes a robust upregulation of thermogenic uncoupling protein 1 (Ucp1) and fibroblast growth factor 21 (Fgf21) gene expression. This increase is not mediated by any of the known mechanisms for PKM2‐regulated gene expression, thus implying the existence of a novel mechanism for PKM2‐dependent effects on gene expression.
Research on Dynamic Corrosion Behavior and the Microstructure of Biomedical Mg–Y–Zn–Zr–Sr in Simulated Body Fluid Solution after Processing by Solution Treatment
Authors: Cao Xin , Jia Qinggong , Xu Chunxiang , Zhang Zhengwei , Ren Conglin , Yang Wenfu , Zhang Jinshan
Published: December 2019

Herein, as‐cast Mg–2Y–Zn–0.4Zr–0.3Sr alloy's solution treatment at 500 °C in the range of 10–35 h, and then cooled in 80° warm water, is used to investigate its dynamic corrosion behavior and surface morphology using a dynamic stimulating human environment device. Based on the result of corrosion behavior and microstructure, the alloy is mainly composed of α‐Mg and W‐phase (Mg3Zn3Y2) in Mg–2Y–Zn–0.4Zr–0.3Sr alloy. With the increase in solution time, the corrosion resistance is prompted due to the uniform microstructure and second phase dissolved into the matrix. The corrosion resistance of Mg–2Y–Zn–0.4Zr–0.3Sr alloy is increased by enhancing solution time before 25 h due to the uniformly distributed second phases and microstructure, which can alleviate the galvanic corrosion. However, increasing solution time exceeding 25 h reduces the corrosion resistance of the alloy due to coarse grains. Furthermore, twinning, which appears in grains interior after solution treatment, has a positive influence on corrosion resistance. Therefore, the good corrosion resistance of solution‐treated Mg–2Y–Zn–0.4Zr–0.3Sr alloy makes it excellent for biomaterial applications.
The Role of Sm in Precipitates, Grain Sizes,and Tensile Properties of As‐Cast and As‐Extruded AZ31–0.3La Alloys
Authors: Fu Li , Hu Wenxin , Le Qichi , Jia Zheng , Lu Lin
Published: December 2019

Herein, the effect of Sm on precipitates, grain sizes, and tensile properties of AZ31–0.3La alloy is investigated. Results indicate that Sm is almost dissolved in α‐Mg matrix with 0.2% content, whereas Al2Sm with two kinds of morphologies forms with further Sm addition. The grain sizes of as‐cast studied alloy increase first and then decrease with increasing Sm addition, whereas the dynamic recrystallization (DRX) grain sizes decrease first and then increase, and the DRX grain size distribution is uniform first and then uneven. During the hot extrusion process, the refinement of DRXed grains is attributed to the particle‐stimulated nucleation (PSN) mechanism. The Rp0.2 (yield strength) of as‐extruded studied alloy is changed from twin‐dominated to slip‐dominated by 0.2% Sm addition, and the basal texture is slightly weakened due to the refined DRX grains and even‐distributed grain size distribution, and the minor solute Sm atoms segregating at grain boundaries. Finally, the Rp0.2 of the as‐extruded AZ31–0.3La alloy is gradually enhanced with increasing Sm addition, and the A (elongation) is increased to 25% with 0.2% Sm addition and maintains to about 20% with 0.6–1.7% Sm addition.
A Stretchable Capacitive Strain Sensor Having Adjustable Elastic Modulus Capability for Wide‐Range Force Detection
Authors: Cao Peng-Juan , Liu Yiwei , Asghar Waqas , Hu Chao , Li Fali , Wu Yuanzhao , Li Yunyao , Yu Zhe , Li Shengbin , Shang Jie , Liu Xincai , Li Run-Wei
Published: December 2019

Stretchable strain sensors are important components of soft robotics, rehabilitation assistance, and human health monitoring systems. However, strain sensors capable of wide‐range force detection with adjustable modulus facilities are highly desirable to obtain mechanical feedback in various scenarios. Herein, a stretchable capacitive strain sensor capable of adjustable modulus and wide‐range force detection is reported. The sensor consists of two liquid metals (LMs) filled thermoplastic elastomer (TPE) tubes encapsulated in flexible silicone. The adjustable modulus capability of the sensor is attained by mounting the sensor with springs of different elastic coefficients. During electromechanical tests, the elastic coefficient‐dependent adjustable modulus is obtained in the range of 0.78–10.3 MPa. After optimizing the performance, a sensor capable of wide force‐sensing range (0.07–74 N), high cyclic stability (>3500 cycles), with low hysteresis, good linearity, and fast response time (<50 ms) is achieved. Finally, a digital display system is developed to display the amount of detected force during the loading of the sensor, which confirms the great capability of the sensor to be applied in joint rehabilitation and soft robotic fields.
Surface Modification of Titanium and Titanium Alloys: Technologies, Developments, and Future Interests
Authors: Zhang Lai-Chang , Chen Liang-Yu , Wang Liqiang
Published: December 2019

Thanks to a considerable number of fascinating properties, titanium (Ti) and Ti alloys play important roles in a variety of industrial sectors. However, Ti and Ti alloys could not satisfy all industrial requirements; the degradation of Ti and Ti alloys always commences on their surfaces in service, which declines the performances of Ti workpieces. Therefore, with aim to further improve their mechanical, corrosion and biological properties, surface modification is often required for Ti and Ti alloys. This article reviews the technologies and recent developments of surface‐modification methods with respect to Ti and Ti alloys, including mechanical, physical, chemical, and biochemical technologies. Conventional methods have limited improvement in the properties and/or restriction on the geometry of workpieces. Therefore, many advanced surface‐modification technologies have emerged in recent decades. New methods make Ti and Ti alloys have better performance and extended applications. With requirement of high surface properties in future. Understanding the mechanism in various surface‐modification methods, combining the advantages of current technologies and developing new coating materials with high performance are required urgently. As such, incorporation of different surface‐modification technologies with high‐performance modified layers may be the mainstream of surface modifications for Ti and Ti alloys.
Polymer Light‐Emitting Electrochemical Cells with Bipolar Electrode‐Dynamic Doping and Wireless Electroluminescence
Authors: Hu Shiyu , Gao Jun
Published: December 2019

This progress report reviews the background and recent developments of polymer light‐emitting electrochemical cells (PLECs). The PLECs of interest have a planar configuration and contain bipolar electrodes (BPEs). A BPE is an electrically floating conductor immersed in an electrochemical cell that contains redox species. When the electrochemical cell is polarized with an externally applied voltage bias, coupled redox reactions are induced wirelessly at the extremities of the BPEs due to the development of a sufficient interfacial potential difference. BPEs can have a dramatic effect on the doping pattern and the emission profiles of PLECs. In a bulk homojunction PLEC containing a large number of dispersed micro‐BPEs, the turn‐on response and light output are greatly enhanced when multiple light‐emitting p–n junctions form throughout the active layer. PLECs offer a solid‐state platform on which the bipolar electrochemistry phenomena can be investigated, and the understanding of the complex PLEC processes can be improved. This progress report highlights several new BPE types as well as their potential applications for device performance enhancement and for the visualized screening of functional materials.
Controlled Growth and Thickness‐Dependent Conduction‐Type Transition of 2D Ferrimagnetic Cr2S3 Semiconductors
Authors: Cui Fangfang , Zhao Xiaoxu , Xu Junjie , Tang Bin , Shang Qiuyu , Shi Jianping , Huan Yahuan , Liao Jianhui , Chen Qing , Hou Yanglong , Zhang Qing , Pennycook Stephen J. , Zhang Yanfeng
Published: December 2019

2D magnetic materials have attracted intense attention as ideal platforms for constructing multifunctional electronic and spintronic devices. However, most of the reported 2D magnetic materials are mainly achieved by the mechanical exfoliation route. The direct synthesis of such materials is still rarely reported, especially toward thickness‐controlled synthesis down to the 2D limit. Herein, the thickness‐tunable synthesis of nanothick rhombohedral Cr2S3 flakes (from ≈1.9 nm to tens of nanometers) on a chemically inert mica substrate via a facile chemical vapor deposition route is demonstrated. This is accomplished by an accurate control of the feeding rate of the Cr precursor and the growth temperature. Furthermore, it is revealed that the conduction behavior of the nanothick Cr2S3 is variable with increasing thickness (from 2.6 to 4.8 nm and >7 nm) from p‐type to ambipolar and then to n‐type. Hereby, this work can shed light on the scalable synthesis, transport, and magnetic properties explorations of 2D magnetic materials.
A Metal–Polyphenol‐Coordinated Nanomedicine for Synergistic Cascade Cancer Chemotherapy and Chemodynamic Therapy
Authors: Ren Zhigang , Sun Shichao , Sun Ranran , Cui Guangying , Hong Liangjie , Rao Benchen , Li Ang , Yu Zujiang , Kan Quancheng , Mao Zhengwei
Published: December 2019

The clinical application of chemotherapy is impeded by the unsatisfactory efficacy and severe side effects. Chemodynamic therapy (CDT) has emerged as an efficient strategy for cancer treatment utilizing Fenton chemistry to destroy cancer cells by converting endogenous H2O2 into highly toxic reactive oxygen species. Apart from the chemotherapeutic effect, cisplatin is able to act as an artificial enzyme to produce H2O2 for CDT through cascade reactions, thus remarkably improving the anti‐tumor outcomes. Herein, an organic theranostic nanomedicine (PTCG NPs) is constructed with high loading capability using epigallocatechin‐3‐gallate (EGCG), phenolic platinum(IV) prodrug (Pt‐OH), and polyphenol modified block copolymer (PEG‐b‐PPOH) as the building blocks. The high stability of PTCG NPs during circulation stems from their strong metal–polyphenol coordination interactions, and efficient drug release is realized after cellular internalization. The activated cisplatin elevates the intracellular H2O2 level through cascade reactions. This is further utilized to produce highly toxic reactive oxygen species catalyzed by an iron‐based Fenton reaction. In vitro and in vivo investigations demonstrate that the combination of chemotherapy and chemodynamic therapy achieves excellent anticancer efficacy. Meanwhile, systemic toxicity faced by platinum‐based drugs is avoided through this nanoformulation. This work provides a promising strategy to develop advanced nanomedicine for cascade cancer therapy.
Kirigami‐Based Light‐Induced Shape‐Morphing and Locomotion
Authors: Cheng Yu‐Chieh , Lu Hao‐Chuan , Lee Xuan , Zeng Hao , Priimagi Arri
Published: December 2019

The development of stimuli‐responsive soft actuators, a task largely undertaken by material scientists, has become a major driving force in pushing the frontiers of microrobotics. Devices made of soft active materials are oftentimes small in size, remotely and wirelessly powered/controlled, and capable of adapting themselves to unexpected hurdles. However, nowadays most soft microscale robots are rather simple in terms of design and architecture, and it remains a challenge to create complex 3D soft robots with stimuli‐responsive properties. Here, it is suggested that kirigami‐based techniques can be useful for fabricating complex 3D robotic structures that can be activated with light. External stress fields introduce out‐of‐plane deformation of kirigami film actuators made of liquid crystal networks. Such 2D‐to‐3D structural transformations can give rise to mechanical actuation upon light illumination, thus allowing the realization of kirigami‐based light‐fuelled robotics. A kirigami rolling robot is demonstrated, where a light beam controls the multigait motion and steers the moving direction in 2D. The device is able to navigate along different routes and moves up a ramp with a slope of 6°. The results demonstrate a facile technique to realize complex and flexible 3D structures with light‐activated robotic functions.
Large‐Scale Synthesis of Strain‐Tunable Semiconducting Antimonene on Copper Oxide
Authors: Niu Tianchao , Meng Qingling , Zhou Dechun , Si Nan , Zhai Shuwei , Hao Xiamin , Zhou Miao , Fuchs Harald
Published: December 2019

Controlled synthesis of 2D structures on nonmetallic substrate is challenging, yet an attractive approach for the integration of 2D systems into current semiconductor technologies. Herein, the direct synthesis of high‐quality 2D antimony, or antimonene, on dielectric copper oxide substrate by molecular beam epitaxy is reported. Delicate scanning tunneling microscopy imaging on the evolution intermediates reveals a segregation growth process on Cu3O2/Cu(111), from ordered dimer chains to packed dot arrays, and finally to monolayer antimonene. First‐principles calculations demonstrate the strain‐modulated band structures in antimonene, which interacts weakly with the oxide surface so that its semiconducting nature is preserved, in perfect agreement with spectroscopic measurements. This work paves the way for large‐scale growth and processing of antimonene for practical implementation.
Optical Properties of 2D 3R Phase Niobium Disulfide and Its Applications as a Saturable Absorber
Authors: Sun Xiaoli , Shi Bingnan , Wang Haoyuan , Lin Na , Liu Shande , Yang Kejian , Zhang Baitao , He Jingliang
Published: December 2019

2D van der Waals metal 3R phase niobium disulfide (3R‐NbS2) has fascinating anisotropic, magnetic, optical, and superconducting properties. Herein, few‐layered 2D 3R‐NbS2 nanosheets are fabricated by combining liquid phase exfoliation and spin‐coating methods. The first principles calculations are performed to explore their electronic band structures to reveal the metallic properties and enhanced optical absorption as thickness increased. The linear and nonlinear optical properties arising from the plasmonic effects and nonequilibrium electrons are studied through the violet–visible–near‐infrared absorption spectroscopy, polarization‐resolved optical microscopy, and open‐aperture Z‐scan methods. The nonlinear absorption coefficient and imaginary part of the third‐order susceptibility are determined to be −2.5 × 106 cm GW−1 and −2.4 × 10−6 esu at 1064 nm. Furthermore, 2D 3R‐NbS2 nanosheets based saturable absorbers are fabricated and applied in solid‐state pulsed lasers, in which a continuous‐wave mode‐locking laser operation at 1050.6 nm is demonstrated with a pulse duration of 302 fs. The results not only verify that 2D metallic materials, such as 3R‐NbS2, are excellent nonlinear optical modulators, but also will arouse a general interest in designing novel materials/structures with 2D metallic materials for electronic and photonic devices.
Enhanced Energy Transfer in Doped Bifluorene Single Crystals: Prospects for Organic Lasers
Authors: Baronas Paulius , Kreiza Gediminas , Mamada Masashi , Maedera Satoshi , Adomėnas Povilas , Adomėnienė Ona , Kazlauskas Karolis , Adachi Chihaya , Juršėnas Saulius
Published: December 2019

Organic single crystals with long‐range molecular order ensure enhanced carrier mobility and stability as well as emission outcoupling, which makes them attractive as gain medium for electrically pumped organic lasers. Unfortunately, effects of excitonic coupling introduce losses degrading optical performance in crystals, hence higher lasing thresholds are observed compared to amorphous films. Here, crystal doping strategy is investigated as a method to avoid pronounced reabsorption and annihilation losses associated with J‐type excitonic coupling, while taking advantage of enhanced exciton transport for efficient energy transfer. Bifluorene‐based derivatives linked with acetylene and ethylene rigid bridges are suitable as host and dopant system forming high‐quality crystals doped at various concentrations (0.5–11.0%). Enhanced exciton transport in host crystal mediates picosecond host–dopant energy transfer enabling 100% transfer efficiency at lower doping concentrations compared to amorphous films. Amplified spontaneous emission threshold of 1.9 µJ cm−2 in 3.5% doped crystal is enabled by minimized exciton annihilation and emission reabsorption losses at optimal doping concentration.
Electrospinning of Metal–Organic Frameworks for Energy and Environmental Applications
Authors: Dou Yibo , Zhang Wenjing , Kaiser Andreas
Published: December 2019

Herein, recent developments of metal–organic frameworks (MOFs) structured into nanofibers by electrospinning are summarized, including the fabrication, post‐treatment via pyrolysis, properties, and use of the resulting MOF nanofiber architectures. The fabrication and post‐treatment of the MOF nanofiber architectures are described systematically by two routes: i) the direct electrospinning of MOF‐polymer nanofiber composites, and ii) the surface decoration of nanofiber structures with MOFs. The unique properties and performance of the different types of MOF nanofibers and their derivatives are explained in respect to their use in energy and environmental applications, including air filtration, water treatment, gas storage and separation, electrochemical energy conversion and storage, and heterogeneous catalysis. Finally, challenges with the fabrication of MOF nanofibers, limitations for their use, and trends for future developments are presented.
Promises of Main Group Metal–Based Nanostructured Materials for Electrochemical CO2 Reduction to Formate
Authors: Han Na , Ding Pan , He Le , Li Youyong , Li Yanguang
Published: December 2019

Selective CO2 reduction to formic acid or formate is the most technologically and economically viable approach to realize electrochemical CO2 valorization. Main group metal–based (Sn, Bi, In, Pb, and Sb) nanostructured materials hold great promise, but are still confronted with several challenges. Here, the current status, challenges, and future opportunities of main group metal–based nanostructured materials for electrochemical CO2 reduction to formate are reviewed. Firstly, the fundamentals of electrochemical CO2 reduction are presented, including the technoeconomic viability of different products, possible reaction pathways, standard experimental procedure, and performance figures of merit. This is then followed by detailed discussions about different types of main group metal–based electrocatalyst materials, with an emphasis on underlying material design principles for promoting the reaction activity, selectivity, and stability. Subsequently, recent efforts on flow cells and membrane electrode assembly cells are reviewed so as to promote the current density as well as mechanistic studies using in situ characterization techniques. To conclude a short perspective is offered about the future opportunities and directions of this exciting field.
Marfan syndrome: Evolving organ manifestations—A 10‐year follow‐up study
Authors: Vanem Thy Thy , Böker Tordis , Sandvik Gunhild F. , Kirkhus Eva , Smith Hans‐Jørgen , Andersen Kai , Drolsum Liv , Lundby Rigmor , Røe Cecilie , Krohg‐Sørensen Kirsten , Geiran Odd R. , Paus Benedicte , Rand‐Hendriksen Svend
Published: December 2019

The age‐dependent penetrance of organ manifestations in Marfan syndrome (MFS) is not known. The aims of this follow‐up study were to explore how clinical features change over a 10‐year period in the same Norwegian MFS cohort. In 2003–2004, we investigated 105 adults for all manifestations in the 1996 Ghent nosology. Ten years later, we performed follow‐up investigations of the survivors (n = 48) who consented. Forty‐six fulfilled the revised Ghent criteria. Median age: females 51 years, range 32–80 years; males 45 years, range 30–67 years. New aortic root dilatation was detected in patients up to 70 years. Ascending aortic pathology was diagnosed in 93 versus 72% at baseline. Sixty‐five percent had undergone aortic surgery compared to 39% at baseline. Pulmonary trunk mean diameter had increased significantly compared to baseline. From inclusion to follow‐up, two patients (three eyes) developed ectopia lentis, four developed dural ectasia, four developed scoliosis, three developed incisional or recurrent herniae, and 14 developed hindfoot deformity. No changes were found regarding protrusio acetabuli, spontaneous pneumothorax, or striae atrophicae. The study confirms that knowledge of incidence and progression of organ manifestations throughout life is important for diagnosis, treatment, and follow‐up of patients with verified or suspected MFS.
13.34 % Efficiency Non‐Fullerene All‐Small‐Molecule Organic Solar Cells Enabled by Modulating the Crystallinity of Donors via a Fluorination Strategy
Authors: Ge Jinfeng , Xie Lingchao , Peng Ruixiang , Fanady Billy , Huang Jiaming , Song Wei , Yan Tingting , Zhang Wenxia , Ge Ziyi
Published: December 2019

Non‐fullerene all‐small‐molecule organic solar cells (NFSM‐OSCs) have shown potential as OSCs, owing to their high purity, easy synthesis and good reproducibility. However, challenges in the modulation of phase separation morphology have limited their development. Herein, two novel small molecular donors, BTEC‐1F and BTEC‐2F, derived from the small molecule DCAO3TBDTT, are synthesized. Using Y6 as the acceptor, devices based on non‐fluorinated DCAO3TBDTT showed an open circuit voltage (Voc) of 0.804 V and a power conversion efficiency (PCE) of 10.64 %. Mono‐fluorinated BTEC‐1F showed an increased Voc of 0.870 V and a PCE of 11.33 %. The fill factor (FF) of di‐fluorinated BTEC‐2F‐based NFSM‐OSC was improved to 72.35 % resulting in a PCE of 13.34 %, which is higher than that of BTEC‐1F (61.35 %) and DCAO3TBDTT (60.95 %). To our knowledge, this is the highest PCE for NFSM‐OSCs. BTEC‐2F had a more compact molecular stacking and a lower crystallinity which enhanced phase separation and carrier transport.
Periodic Nucleation of Calcium Phosphate in a Stirred Biocatalytic Reaction
Authors: Bohner Bíborka , Bánsági Tamás , Tóth Ágota , Horváth Dezső , Taylor Annette F.
Published: December 2019

Highly ordered superstructures composed of inorganic nanoparticles appear in natural and synthetic systems, however the mechanisms of non‐equilibrium self‐organization that may be involved are still poorly understood. Herein, we performed a kinetic investigation of the precipitation of calcium phosphate using a process widely found in microorganisms: the hydrolysis of urea by enzyme urease. With high initial ratio of calcium ion to phosphate, periodic precipitation was obtained accompanied by pH oscillations in a well‐stirred, closed reactor. We propose that an internal pH‐regulated change in the concentration of phosphate ion is the driving force for periodicity. A simple model involving the biocatalytic reaction network coupled with burst nucleation of nanoparticles above a critical supersaturation reproduced key features of the experiments. These findings may provide insight to the self‐organization of nanoparticles in biomineralization and improve design strategies of biomaterials for medical applications.
Hypervalent‐Iodine‐Mediated Carbon–Carbon Bond Cleavage and Dearomatization of 9H‐Fluoren‐9‐ols
Authors: Deng Ruixian , Zhan Shuming , Li Chunyu , Gu Zhenhua
Published: December 2019

A transition‐metal‐free synthesis of spiro compounds from 9H‐fluoren‐9‐ols mediated by hypervalent iodine is reported. In this reaction, an unprecedented β‐carbon elimination of tertiary alkoxyliodine(III) to form new diaryliodonium salts is proposed. The obtained phenol intermediates undergo oxidative dearomatization to furnish a class of oxo‐spiro compounds. This domino reaction significantly increases the complexity of these molecules and shows excellent regio‐ and stereoselectivity.
C1 Oxidation/C2 Reduction Isomerization of Unprotected Aldoses Induced by Light/Ketone
Authors: Masuda Yusuke , Tsuda Hiromu , Murakami Masahiro
Published: December 2019

Unprotected aldoses in water undergo an isomerization reaction via a radical pathway when irradiated with light in the presence of water‐soluble benzophenone. Whereas its anomeric carbon (C1) is oxidized to a carboxy group, the hydroxy group on the C2 carbon is replaced by hydrogen. The generated 2‐deoxy lactones are readily reduced to the corresponding 2‐deoxy aldoses, which are often contained in bioactive compounds.
Semiconducting Polymer Dots with Dual‐Enhanced NIR‐IIa Fluorescence for Through‐Skull Mouse‐Brain Imaging
Authors: Zhang Zhe , Fang Xiaofeng , Liu Zhihe , Liu Haichao , Chen Dandan , He Shuqing , Zheng Jie , Yang Bing , Qin Weiping , Zhang Xuanjun , Wu Changfeng
Published: December 2019

Fluorescence probes in the NIR‐IIa region show drastically improved imaging owing to the reduced photon scattering and autofluorescence in biological tissues. Now, NIR‐IIa polymer dots (Pdots) are developed with a dual fluorescence enhancement mechanism. First, the aggregation induced emission of phenothiazine was used to reduce the nonradiative decay pathways of the polymers in condensed states. Second, fluorescence quenching was minimized by different levels of steric hindrance to further boost the fluorescence. The resulting Pdots displayed a fluorescence QY of ca. 1.7 % in aqueous solution, suggesting an enhancement of ca. 21 times in comparison with the original polymer in tetrahydrofuran (THF) solution. Small‐animal imaging by using the NIR‐IIa Pdots exhibited a remarkable improvement in penetration depth and signal to background ratio, as confirmed by through‐skull and through‐scalp fluorescent imaging of the cerebral vasculature of live mice.