bluuebunny/crossref_metadata_2025 huggingface dataset:
Situando os debates sobre a avaliação da pós-graduação: os estudos do campo pelo campo
Authors: Magalhães Ana Maria Da Silva , Real Giselle Cristina Martins
Published: September 2018

Assim como os demais níveis de ensino, a pós-graduação stricto sensu no Brasil tem passado por um processo de significativa expansão e, com isso, ampliam-se os estudos e debates acerca da temática, especialmente no que tange ao seu processo de avaliação. Diante disso, o presente estudo objetiva analisar o debate acerca da avaliação da pós-graduação, a partir do mapeamento da produção bibliográfica de artigos publicados em periódicos qualificados, no período de 1999 a 2017. Além de mapear o tema, o presente trabalho busca trazer as principais discussões presentes nesse tipo de produção. O estudo realizado acerca da produção sobre avaliação da pós-graduação permite afirmar que não existe consenso no debate, sendo que as opiniões sobre a sistemática de avaliação divergem, muito embora se verifique a ênfase para a produção intelectual em seus diversos aspectos. Nesse sentido, ‘o campo’, apesar das disputas e dissensos, ainda tem referenciado a performatividade como estratégia de viabilização da qualidade da pós-graduação brasileira.
Veronico beccabungae-Mimuletum guttati, a new plant community in Slovakia
Authors: Hrivnák Richard , Slezák Michal , Marhold Karol
Published: September 2018

Vegetation with high coverage by the alien species Mimulus guttatus was studied in the hilly regions of central Slovakia in 2015 and 2016. The floristic composition of these stands was recorded in ten phytosociological relevés corresponding to the Veronico beccabungae-Mimuletum guttati (alliance Glycerio-Sparganion) association. This association was reported for the first time in Slovakia in this study. This association was found to be closed or almost closed (mean coverage value of herb layer = 92%) and formed relatively species-rich stands (15 species per relevé), usually in narrow and small patches along the upper parts of streams and their spring areas in uplands at altitudes from 561 to 1,048 m. Localities with the Veronico beccabungae-Mimuletum guttati association were characterized by typical mountain climates, with both relatively low mean annual air temperature (5.5°C) and high mean annual precipitation (885 mm). While water temperature (~13°C) of these habitats varied considerably among streams (7.4–19.9°C), their herbaceous vegetation preferred neutral to slightly alkaline water (pH = 6.1–7.5) with low amounts of soluble mineral matter (~72.6 μS cm−1). This kind of vegetation was most often developed on sites with coarser sediments (stone, gravel, and sand) formed from crystalline bedrock. A comparison of vegetation data of the Veronico beccabungae-Mimuletum guttati association across Central Europe demonstrated considerable floristic variability among regions.
Arabidopsis high temperature stress research
Authors: Dolzblasz Alicja , Dołzbłasz Sylwia
Published: September 2018

The rise in global temperature and increasingly frequent heat waves may severely disturb plant growth and productivity. Throughout the life cycle of vascular plants, which may last even thousands of years, various aboveground structures are constructed due to the activity of the shoot apical meristem (SAM). A pool of dividing, undifferentiated stem cells is maintained within a SAM, which facilitates self-perpetuation of the meristem and provides cells for growth and organogenesis. Unsurprisingly, there has been a growing interest to study the impact of increased temperatures on the development and molecular response of the model plant Arabidopsis thaliana. Unfortunately, the experimental setups are highly variable and key aspects of plant development are regularly neglected. Thus, in this short review, we highlight the experimental variables and address SAM maintenance in the context of elevated temperature research.
Studies on electrodeposited Zn-Fe alloy coating on mild steel and its characterization
Authors: Bhat Ramesh , Hegde Ampar Chitharanjan
Published: September 2018

Chloride bath containing ZnCl2 ∙7H2O, FeCl2 ∙H2O and a combination of sulphamic acid and citric acid (SA+CA) were optimized for electrodeposition of bright Zn-Fe alloy coating on the mild steel. Bath constituents and operating parameters were optimized by the Hull cell method for highest performance of the coating against corrosion. The effect of current density and temperature on deposit characteristics such as corrosion resistance, hardness, thickness, cathode current efficiency and glossiness, were studied. Potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) methods were used to assess corrosion behaviour. Surface morphology of coatings was examined using scanning electron microscopy (SEM). The Zn-Fe alloy with intense peaks corresponding to Zn (100) and Zn (101) phases, evidenced by X-ray diffraction (XRD) study, showed the highest corrosion resistance. A new and economical chloride bath for electrodeposition of bright Zn-Fe alloy coating on mild steel was proposed and discussed.
Aristotle on the Indetermination of Accidental Causes and Chance
Authors: Rossi Gabriela ,   Philosophy Documentation Center
Published: September 2018

This article offers an interpretation of Aristotle’s tenet that chance and accidental causes are indeterminate. According to one existing reading, the predicate ‘indeterminate’ is said of the effect of chance (and of accidental causes), meaning ‘causally indeterminate.’ Another reading claims instead that the predicate ‘indeterminate’ is said of the cause of a chance event, meaning something close to ‘potentially infinite in number.’ For my part, I contend that the predicate ‘indeterminate,’ when applied to Aristotle’s concept of accidental cause and to chance, is best understood as a second-order predicate. More precisely, Aristotle uses ‘indeterminate’ to qualify a certain type of causal relation, rather than to indicate a quality of the causal power or of the effect. As a preparatory step in my argument, I contend that ‘accidental’ and ‘per se’ are also best understood as second-order predicates of ‘cause,’ and as a corollary of my main thesis I offer an interpretation of how chance involves an infinite number of possible causes.
Full review from engineering to programming: smart agent applications using ARL
Authors: Juneidi Salaheddin
Published: September 2018

Modern computing systems are generally based on embedded smart agents. They are introduced as a new trend of computing paradigm; in which we can define smart entities in software system or robotic machines. This modern trend of technology calls for new approaches in both software engineering and programming techniques. Unlike Object Oriented programing languages, Agent oriented programming languages and agent oriented engineering are not stable and are not well defined, on the contrary, object orientation is well defined and consistent. From the fact that, agent oriented programming is an implementation of agent oriented engineering; this article follows this sequence and it tackles the application view over agent oriented software system. (Agent Role Locking) ARL theory is used to design and implement agents in software system, on the other hand Java threads are used to implement agents. The main aim is to show innovative incorporation relationship between engineering methodologies and programming application in Smart Agent Orientated Technology.
TFAP2 transcription factors are regulators of lipid droplet biogenesis
Authors: Scott Cameron C , Vossio Stefania , Rougemont Jacques , Gruenberg Jean
Published: September 2018

How trafficking pathways and organelle abundance adapt in response to metabolic and physiological changes is still mysterious, although a few transcriptional regulators of organellar biogenesis have been identified in recent years. We previously found that the Wnt signaling directly controls lipid droplet formation, linking the cell storage capacity to the established functions of Wnt in development and differentiation. In the present paper, we report that Wnt-induced lipid droplet biogenesis does not depend on the canonical TCF/LEF transcription factors. Instead, we find that TFAP2 family members mediate the pro-lipid droplet signal induced by Wnt3a, leading to the notion that the TFAP2 transcription factor may function as a ‘master’ regulator of lipid droplet biogenesis.
Assessing bird avoidance of high-contrast lights using a choice test approach: implications for reducing human-induced avian mortality
Authors: Goller Benjamin , Blackwell Bradley F. , DeVault Travis L. , Baumhardt Patrice E. , Fernández-Juricic Esteban
Published: September 2018

Background

Avian collisions with man-made objects and vehicles (e.g., buildings, cars, airplanes, power lines) have increased recently. Lights have been proposed to alert birds and minimize the chances of collisions, but it is challenging to choose lights that are tuned to the avian eye and can also lead to avoidance given the differences between human and avian vision. We propose a choice test to address this problem by first identifying wavelengths of light that would over-stimulate the retina using species-specific perceptual models and by then assessing the avoidance/attraction responses of brown-headed cowbirds to these lights during daytime using a behavioral assay.

Methods

We used perceptual models to estimate wavelength-specific light emitting diode (LED) lights with high chromatic contrast. The behavioral assay consisted of an arena where the bird moved in a single direction and was forced to make a choice (right/left) using a single-choice design (one side with the light on, the other with the light off) under diurnal light conditions.

Results

First, we identified lights with high saliency from the cowbird visual perspective: LED lights with peaks at 380 nm (ultraviolet), 470 nm (blue), 525 nm (green), 630 nm (red), and broad-spectrum (white) LED lights. Second, we found that cowbirds significantly avoided LED lights with peaks at 470 and 630 nm, but did not avoid or prefer LED lights with peaks at 380 and 525 nm or white lights.

Discussion

The two lights avoided had the highest chromatic contrast but relatively lower levels of achromatic contrast. Our approach can optimize limited resources to narrow down wavelengths of light with high visual saliency for a target species leading to avoidance. These lights can be used as candidates for visual deterrents to reduce collisions with man-made objects and vehicles.
Variably protease‐sensitive prionopathy presenting within ALS/FTD spectrum
Authors: Vicente‐Pascual Mikel , Rossi Marcello , Gámez Josep , Lladó Albert , Valls Josep , Grau‐Rivera Oriol , Ávila Polo Rainiero , Llorens Franc , Zerr Inga , Ferrer Isidre , Nos Carlos , Parchi Piero , Sánchez‐Valle Raquel , Gelpí Ellen
Published: September 2018

We report clinico‐pathological features of a 65‐year‐old woman and a 56‐year‐old man with a 5‐year clinical history who had clinical and neuropathological characteristics of upper and lower motor neuron disease consistent with amyotrophic lateral sclerosis, and a frontotemporal atrophy pattern in case 2 without TDP‐43 pathology. Instead, spongiform change and pathological prion protein deposits were observed in several brain regions. No prion protein gene mutations were found. Western blot analysis showed a five‐band profile compatible with variably protease‐sensitive prionopathy. We conclude that this disease can display prolonged disease duration and clinico‐pathological features within the ALS/FTLD spectrum.
Anti–RNPC‐3 (U11/U12) Antibodies in Systemic Sclerosis in Patients With Moderate‐to‐Severe Gastrointestinal Dysmotility
Authors: McMahan Zsuzsanna H. , Domsic Robyn T. , Zhu Lei , Medsger Thomas A. , Casciola‐Rosen Livia , Shah Ami A.
Published: September 2018

Objective

To examine the association of anti–RNPC‐3 antibodies in patients with systemic sclerosis (scleroderma or SSc) with selected gastrointestinal (GI) tract complications.

Methods

Sera from patients with SSc with or without severe GI dysfunction (total parenteral nutrition dependence) from the Johns Hopkins Scleroderma Center were screened for anti–RNPC‐3 antibodies. We then examined anti–RNPC‐3–positive cases and negative SSc controls from the University of Pittsburgh and the University of Pittsburgh Medical Center (UPMC) scleroderma cohort to confirm our findings and to examine whether specific GI features were associated with anti–RNPC‐3 antibodies.

Results

In the discovery cohort, patients with SSc with severe GI dysfunction (n = 37) and without GI dysfunction (n = 38) were screened for anti–RNPC‐3 antibodies. The former were more likely to have anti–RNPC‐3 antibodies (14% versus 3%; P = 0.11). In the Pittsburgh cohort, moderate‐to‐severe GI dysfunction (Medsger GI score ≥2) was present in 36% of anti–RNPC‐3–positive patients versus 15% of anti–RNPC‐3–negative patients (P ≤ 0.01). Anti–RNPC‐3–positive patients were more likely to be male (31% versus 15%; P = 0.04), African American (18% versus 6%; P = 0.02), have esophageal dysmotility (93% versus 62%; P < 0.01), and interstitial lung disease (ILD) (77% versus 35%; P < 0.01). After adjusting for relevant covariates and potential confounders, moderate‐to‐severe GI disease was associated with anti–RNPC‐3 antibodies (odds ratio [OR] 3.8 [95% confidence interval (95% CI) 1.0–14.3]), and ILD trended toward significance (OR 2.8 [95% CI 1.0–8.2]).

Conclusion

Patients with SSc and anti–RNPC‐3 antibodies are more likely to be male and African American and to have moderate‐to‐severe GI disease and ILD. Further studies on larger patient cohorts may be helpful in further defining subsets of patients with SSc at risk for severe GI involvement.
Good news in NSDUH: New heroin use down
Authors: Knopf Alison
Published: September 2018

New users of heroin were down in 2017 from the previous year, according to the National Survey on Drug Use and Health (NSDUH) released Sept. 14. The decline is dramatic: from 170,000 new heroin users in 2016, to 81,000 in 2017. But there are concerns about increasing cocaine and methamphetamine use, a continuing increase in widespread use of marijuana, and increased substance use in the “transitional‐age” (18–25‐year‐olds) population and pregnant women.
‘Incentivizing Recovery’ follow‐up: White paper was a ‘first step’
Authors: Knopf Alison
Published: September 2018

Last week's issue featured the announcement of a new payment model for addiction treatment, a combination of capitated and bundled reimbursement that places the treatment provider at risk in the event of repeat admissions. Greg Williams, executive vice president of Facing Addiction with NCADD, described the rationale for the system: Treatment providers should not be paid if patients don't get well. Anne Marie Polak, senior director at Leavitt Partners and in charge of the “Incentivizing Recovery” project the organization is convening, described the basics of how the project works. None of the treatment organizations participated in the project, which resulted in the white paper released Sept. 7 (see ADAW, Sept. 17).
SERS Nanoprobes in Biologically Raman Silent Region for Tumor Cell Imaging and In Vivo Tumor Spectral Detection in Mice
Authors: Liang Duanwei , Jin Qingqing , Yan Ning , Feng Jie , Wang Jing , Tang Xinjing
Published: September 2018

Surface enhanced Raman scattering (SERS) is widely used in biological applications due to its high sensitivity and deep tissue penetration. Most SERS nanoprobes with fluorophore attachments have Raman signals between 1400 and 1700 cm−1. Here, a series of SERS nanoprobes anchored with alkyne moieties in the biologically Raman‐silent region through CAu bond formation is prepared. To achieve target‐specific recognition, two nucleic acid aptamers (AS1411 and MUC1) and two control oligonucleotides (C‐con and T‐con) with the same alkyne moiety are also attached on the Au surface, respectively. Both aptamer‐charged SERS nanoprobes successfully target MCF‐7 cells, which could possibly achieve cross‐check of target cells and overcome the possible false positive results. And the limit of detection reaches up to five cancer cells, which has great potential in circulating tumor cells detection. Further in vivo studies indicate that both SERS nanoprobes are successfully employed to target tumors in living mice with an obvious signal (≈2205 cm−1) at the Raman silent region after tail intravenous injection for the first time.
Printing of Responsive Photonic Cellulose Nanocrystal Microfilm Arrays
Authors: Zhao Tianheng H. , Parker Richard M. , Williams Cyan A. , Lim Kevin T. P. , Frka‐Petesic Bruno , Vignolini Silvia
Published: September 2018

Interactive materials capable of changing appearance upon exposure to external stimuli, such as photonic inks, are generally difficult to achieve on a large scale as they often require self‐assembly processes that are difficult to control macroscopically. Here this problem is overcome by preparing arrays of cellulose nanocrystal (CNC) microfilms from discrete nanoliter sessile droplets. The obtained microfilms show extremely uniform and intense color, enabling exceptional consistency in optical appearance across the entire array. The color can be controlled through the initial ink formulation, enabling the printing of polychromatic dot‐matrix images. Moreover, the high surface‐to‐volume ratio of the microfilms and the intrinsic hydrophilicity of the natural building block allow for a dramatic real‐time colorimetric response to changes in relative humidity. The printed CNC microfilm arrays overcome the existing issues of scalability, optical uniformity, and material efficiency, which have held back the adoption of CNC‐based photonic materials in cosmetics, interactive‐pigments, or anticounterfeit applications.
The Interaction between Quantum Dots and Graphene: The Applications in Graphene‐Based Solar Cells and Photodetectors
Authors: Wu Jianghong , Lu Yanghua , Feng Sirui , Wu Zhiqian , Lin Shuyuan , Hao Zhenzhen , Yao Tianyi , Li Xinming , Zhu Hongwei , Lin Shisheng
Published: September 2018

Graphene with a series of neoteric electronic and optical properties is an intriguing building block for optoelectronic devices. Over the past decade, graphene‐based solar cells (SCs) and photodetectors (PDs) which can convert light signals to electrical signals have received burgeoning exploration. However, limited light absorption hampers the performance of these devices. Quantum dots (QDs) possess a strong confinement effect, a large exciton energy, and long exciton lifetime, enhancing the interaction between incident light and graphene. Especially, as the density of states near the Dirac point of graphene is ultralow, it is easy to modify the Fermi level of graphene by inserting quantum dots at the interface between graphene and light, thereby enhancing the performance of graphene‐based optoelectronic devices. The characteristics of QDs and crucial physical mechanisms of the interaction and energy transfer in QDs/graphene nanohybrids are systematically addressed. The factors influencing the efficiency of energy transfer are also analyzed quantitatively. Moreover, the experimental process of QD‐enhanced technologies for SCs, photoconductors, phototransistors, and photodiode PDs is reviewed. Eventually, a conclusion is given and the remaining challenges and future development for QDs/2D materials hybrid systems is discussed. Possible steps toward large‐scale commercial applications and integration into optoelectronic networks are suggested.
Free‐Standing Electrodes Derived from Metal–Organic Frameworks/ Nanofibers Hybrids for Membrane Capacitive Deionization
Authors: Ding Meng , Bannuru Kranthi K. R. , Wang Ye , Guo Lu , Baji Avinash , Yang Hui Ying
Published: September 2018

Membrane capacitive deionization is considered as a promising technology for water treatment with their high efficiency, low capital cost, and environmental friendliness. However, the complex fabrication process of membrane capacitive deionization electrodes mainly hinders its viability in large‐scale applications. In this study, a facile and general method to prepare free‐standing electrodes for membrane capacitive deionization with an excellent electrosorption performance is presented. Electrospun nanofibers enclosing zinc‐based nanoparticles are fabricated as the templates. After pyrolysis, the nitrogen‐doped carbon nanofiber hybrids with high conductivity and a high surface area can be obtained readily. The carbon electrode material is able to achieve a salt adsorption capacity of 43.3 mg g−1 at 1.4 V in 1000 mg L−1 NaCl aqueous solution. Overall, the carbon nanofiber hybrids electrode prepared by electrospinning and pyrolysis shows a great potential in membrane capacitive deionization for industrial applications.
Stereolithography for Personalized Left Atrial Appendage Occluders
Authors: Robinson Sanlin S. , Aubin Cameron A. , Wallin Thomas J. , Gharaie Saleh , Xu Patricia A. , Wang Kaiyang , Dunham Simon N. , Mosadegh Bobak , Shepherd Robert F.
Published: September 2018

Advancements in 3D additive manufacturing have spurred the development of effective patient‐specific medical devices. Prior applications are limited to hard materials, however, with few implementations of soft devices that better match the properties of natural tissue. This paper introduces a rapid, low cost, and scalable process for fabricating soft, personalized medical implants via stereolithography of elastomeric polyurethane resin. The effectiveness of this approach is demonstrated by designing and manufacturing patient‐specific endocardial implants. These devices occlude the left atrial appendage, a complex structure within the heart prone to blood clot formation in patients with atrial fibrillation. Existing occluders permit residual blood flow and can damage neighboring tissues. Here, the robust mechanical properties of the hollow, printed geometries are characterized and stable device anchoring through in vitro benchtop testing is confirmed. The soft, patient‐specific devices outperform non‐patient‐specific devices in embolism and occlusion experiments, as well as in computational fluid dynamics simulations.
Development of Biocompatible HA Hydrogels Embedded with a New Synthetic Peptide Promoting Cellular Migration for Advanced Wound Care Management
Authors: Wang Sun Young , Kim Hyosuk , Kwak Gijung , Yoon Hong Yeol , Jo Sung Duk , Lee Ji Eun , Cho Daeho , Kwon Ick Chan , Kim Sun Hwa
Published: September 2018

In the past few years, there have been many efforts underway to develop effective wound healing treatments for traumatic injuries. In particular, wound‐healing peptides (WHPs) and peptide‐grafted dressings hold great promise for novel therapeutic strategies for wound management. This study reports a topical formulation of a new synthetic WHP (REGRT, REG) embedded in a hyaluronic acid (HA)‐based hydrogel dressing for the enhancement of acute excisional wound repair. The copper‐free click chemistry is utilized to form biocompatible HA hydrogels by cross‐linking dibenzocyclooctyl‐functionalized HA with 4‐arm poly(ethylene glycol) (PEG) azide. The HA hydrogels are grafted with the REG peptide, a functional derivative of erythroid differentiation regulator1, displaying potent cell motility‐stimulating ability, thus sustainably releasing physiologically active peptides for a prolonged period. Combined with the traditional wound healing benefits of HA, the HA hydrogel embedded REG (REG‐HAgel) accelerates re‐epithelialization in skin wound healing, particularly by promoting migration of fibroblasts, keratinocytes, and endothelial cells. REG‐HAgels improve not only rate, but quality of wound healing with higher collagen deposition and more microvascular formation while being nontoxic. The peptide‐grafted HA hydrogel system can be considered as a promising new wound dressing formulation strategy for the treatment of different types of wounds with combinations of various natural and synthetic WHPs.
All‐Inorganic Perovskite Quantum Dot‐Monolayer MoS2 Mixed‐Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector
Authors: Wu Hualin , Si Haonan , Zhang Zihan , Kang Zhuo , Wu Pingwei , Zhou Lixin , Zhang Suicai , Zhang Zheng , Liao Qingliang , Zhang Yue
Published: September 2018

2D transition metal dichalcogenide (2D‐TMD) materials and their van der Waals heterostructures (vdWHs) have inspired worldwide efforts in the fields of electronics and optoelectronics. However, photodetectors based on 2D/2D vdWHs suffer from performance limitations due to the weak optical absorption of their atomically thin nature. In this work, taking advantage of an excellent light absorption coefficient, low‐temperature solution‐processability, and long charge carrier diffusion length, all‐inorganic halides perovskite CsPbI3−xBrx quantum dots are integrated with monolayer MoS2 for high‐performance and low‐cost photodetectors. A favorable energy band alignment facilitating interfacial photocarrier separation and efficient carrier injection into the MoS2 layer inside the 0D–2D mixed‐dimensional vdWHs are confirmed by a series of optical characterizations. Owing to the synergistic effect of the photogating mechanism and the modulation of Schottky barriers, the corresponding phototransistor exhibits a high photoresponsivity of 7.7 × 104 A W−1, a specific detectivity of ≈5.6 × 1011 Jones, and an external quantum efficiency exceeding 107%. The demonstration of such 0D–2D mixed‐dimensional heterostructures proposed here would open up a wide realm of opportunities for designing low‐cost, flexible transparent, and high‐performance optoelectronics.
Toward Programmable Materials for Wearable Electronics: Electrical Welding Turns Sensors into Conductors
Authors: Chellattoan Ragesh , Lube Vinicius , Lubineau Gilles
Published: September 2018

Stretchable electrical conductors and stretchable strain sensors are two key components in applications such as soft robotics, artificial soft skins, and wearable electronics. Very different approaches are usually implemented to design either conductors or sensors. Here, transformation of an electrically conductive material from a sensor to a conductor using electrical welding (e‐welding) is proposed. This method is demonstrated in the case of a thermoplastic polymer sponge decorated with silver nanowires. The sensor‐like behavior of the sponge is programmed by e‐welding into conductor‐like behavior, i.e., suppressing the gauge factor by 86%, without varying the density of the silver nanowires. An application of e‐welding in the fabrication of a sensor‐conductor hybrid material that may be applied as soft artificial skin in robotics is demonstrated.
Bioreactor scale‐down studies of suspended plant cell cultures
Authors: Cheung Caleb K. ‐L. , Leksawasdi Noppol , Doran Pauline M.
Published: September 2018

The effect of dissolved oxygen fluctuations on suspended plant cells was investigated using a scale‐down stirred bioreactor system to simulate the heterogeneous conditions found in large‐scale vessels. Transgenic Nicotiana tabacum cells expressing IgG1 antibody and Thalictrum minus cells producing berberine were subjected to gas switching cycles based on a stochastic model of log‐normal circulation time distributions. Because pumping severely damaged the cells, the scale‐down approach was restricted to a single‐vessel system. Dissolved oxygen oscillations of amplitude about ±5% air saturation were achieved in the N. tabacum cultures; however, most simulations produced highly damped fluctuations due to oxygen transfer limitations and no significant effect on the cultures was observed. In contrast, berberine production by T. minus cells was reduced when fluctuations of ±10–15% air saturation were superimposed on mean dissolved oxygen tensions of 25 and 35% air saturation. This work demonstrates that dissolved oxygen gradients such as those found in large‐scale mixing vessels can be detrimental to plant cell cultures even when sufficient average dissolved oxygen levels are provided. © 2018 American Institute of Chemical Engineers AIChE J, 64: 4281–4288, 2018
Enhancing Squeezing and Nonclassicality of Light in Atom–Optomechanical Systems
Authors: Guo Yanqiang , Guo Xiaomin , Li Pu , Shen Heng , Zhang Jing , Zhang Tiancai
Published: September 2018

Quadrature squeezing of light is investigated in a hybrid atom–optomechanical system comprising a cloud of two‐level atoms and a movable mirror mediated by a single‐mode cavity field. When the system is at high temperatures with quadrature fluctuations of light much above the standard quantum limit (SQL), excitation counting on the collective atomic state can effectively reduce the light noise close to the SQL. When the system is at low temperatures, considerable squeezing of light below the SQL is found at steady state. The squeezing is enhanced by simply increasing the atom–light coupling strength with the laser power optimized close to the unstable regime, and further noise reduction is achieved by decreasing the various losses in the system. The presence of atoms and excitation counting on the atoms lessen the limitation of thermal noise, and the squeezing can be achieved at an environment temperature of the order K. The nonclassicality of the light, embodied by the negative distributions of the Wigner function, is also studied by making non‐Gaussian measurements on the atoms. It is shown that with feasible parameters, excitation counting on the atoms is effective in inducing strongly optical nonclassicality.
Design of a Multicompartment Hydrogel that Facilitates Time‐Resolved Delivery of Combination Therapy and Synergized Killing of Glioblastoma
Authors: Majumder Poulami , Baxa Ulrich , Walsh Scott T. R. , Schneider Joel P.
Published: September 2018

There is significant current interest in identifying new combination therapies that synergize to treat disease, and it is becoming increasingly clear that the temporal resolution of their administration greatly impacts efficacy. To facilitate effective delivery, a multicompartment hydrogel material was developed that is composed of spherical vesicles interlaced within a self‐assembled peptide‐based network of physically crosslinked fibrils that allows time‐resolved independent co‐delivery of small molecules. This material architecture effectively delivers the EGFR kinase inhibitor Erlotinib (ERL) and Doxorubicin (DOX, DNA intercalator) in an ERL→DOX sequential manner to synergistically kill glioblastoma, the most aggressive form of brain cancer.
Intercalation‐enhanced “Click” Crosslinking of DNA
Authors: Tera Masayuki , Harati Taji Zahra , Luedtke Nathan W.
Published: September 2018

DNA–DNA cross‐linking agents constitute an important family of chemotherapeutics that non‐specifically react with endogenous nucleophiles and therefore exhibit undesirable side effects. Here we report a cationic Sondheimer diyne derivative “DiMOC” that exhibits weak, reversible intercalation into duplex DNA (Kd=15 μm) where it undergoes tandem strain‐promoted cross‐linking of azide‐containing DNA to give DNA‐DNA interstrand crosslinks (ICLs) with an exceptionally high apparent rate constant kapp=2.1×105 m−1 s−1. This represents a 21 000‐fold rate enhancement as compared the reaction between DIMOC and 5‐(azidomethyl)‐2′‐deoxyuridine (AmdU) nucleoside. As single agents, 5′‐bispivaloyloxymethyl (POM)‐AmdU and DiMOC exhibited low cytotoxicity, but highly toxic DNA‐DNA ICLs were generated by metabolic incorporation of AmdU groups into cellular DNA, followed by treatment of the cells with DiMOC. These results provide the first examples of intercalation‐enhanced bioorthogonal chemical reactions on DNA, and furthermore, the first strain‐promoted double click (SPDC) reactions inside of living cells.
Biomimetic Synthesis of (+)‐Aspergillin PZ
Authors: Reyes Julius R. , Winter Nils , Spessert Lukas , Trauner Dirk
Published: September 2018

The cytochalasans are a large family of polyketide natural products with potent bioactivities. Amongst them, the aspochalasins show particularly intricate and fascinating structures. To gain insight into their structural diversity and innate reactivity, we have developed a rapid synthesis of aspochalasin D, the central member of the family. It proceeded in 13 steps starting from divinyl carbinol and utilized a high pressure Diels–Alder reaction that features high regio‐ and stereoselectivity. So far, our work has culminated in a biomimetic synthesis of aspergillin PZ, an intricate pentacyclic aspochalasan.
Modulating Self‐Assembly of DNA Crystals with Rationally Designed Agents
Authors: Zhao Jiemin , Zhao Yue , Li Zhe , Wang Yong , Sha Ruojie , Seeman Nadrian C. , Mao Chengde
Published: September 2018

This manuscript reports a strategy for controlling the crystallization kinetics and improving the quality of engineered self‐assembled 3D DNA crystals. Growing large, high‐quality biomacromolecule crystals is critically important for determining the 3D structures of biomacromolecules. It often presents a great challenge to structural biologists. Herein, we introduce a rationally designed agent to modulate the crystallization process. Under such conditions, fewer, but larger, crystals that yield diffraction patterns of modestly higher resolution are produced compared with the crystals from conditions without the modulating agent. We attribute the improvement to a smaller number of nuclei and slow growth rate of crystallization. This strategy is expected to be generally applicable for crystallization of other biomacromolecules.
Characterizing the degradation behavior of calcium alginate fibers wound dressings fabricated by needle‐punching process
Authors: Gao Yingjun , Jin Xiangyu
Published: September 2018

Calcium alginate fibers (CAFs) needle‐punched nonwovens are natural polysaccharide biological dressings. Wound exudates cause salt degradation of CA macromolecules. Herein, degradation process, degradation mechanism, and performance variations of degraded dressings were investigated. The functional group structures changed slightly, while the aggregation structure degraded remarkably. CAF turned into composite containing fiber and sodium alginate (SA) gels, finally degraded to SA gels. The initial degraded dressings maintained stable three‐dimensional (3D) interconnected porous structure. As the degradation and re‐entanglement of CAFs, the dressings changed from volatile composite constituted by degraded CAFs and SA gels to steady foam‐like structure bonded by SA gels with independent pores. Degradation caused significant changes in the interaction between CAFs, altering the stretching and compressing processes of the dressings. SA gels and CAFs formed a stable 3D structure with certain mechanical properties. The bonded SA gels improved the absorption, diffusion, and storage of the wound exudates in the degraded dressings. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46670.
Thermodynamically and kinetically favored locations of rice husk ash particles in the phase structure, and the properties of epoxidized natural rubber/thermoplastic polyurethane blends
Authors: Pongdong Wiphawadee , Kummerlöwe Claudia , Vennemann Norbert , Thitithammawong Anoma , Nakason Charoen
Published: September 2018

This article aims to study the influences of the selective location of rice husk ash (RHA) particles on morphological, mechanical, and dynamic properties of epoxidized natural rubber and thermoplastic polyurethane blends (ENR/TPU). Thermodynamic aspects, that is, interfacial tension and work of adhesion were assessed from estimates based on surface tension. It was found that the RHA particles had stronger interactions with the ENR than the TPU, of the co‐continuous phases. The phase structure was mainly controlled by kinetic factors, particularly by the mixing sequence, and to a lesser degree by thermodynamics. Furthermore, the microstructure with RHA particles dispersed in the ENR co‐continuous phase was found to give enhanced mechanical properties. This might be attributed to the higher work of adhesion between ENR and RHA that stabilized the encapsulated RHA particles against shear and elongational stresses, during melt mixing and in the final products. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46681.
Temperature‐responsive alginate‐g‐poly(N,N‐diethylacrylamide) copolymer: Synthesis, characterization, and swelling behavior
Authors: Işıklan Nuran , Altınışık Zeynep
Published: September 2018

Temperature‐responsive polymers have recently gained importance due to their applications in drug delivery. Herein, temperature‐responsive graft copolymer (Alg‐g‐PDEAAm) of alginate and N,N‐diethylacrylamide was synthesized by microwave‐assisted copolymerization using potassium persulfate/N,N,N′,N′‐tetramethylethylenediamine initiator system. The reaction conditions for the best grafting (331%) have been optimized by changing microwave irradiation time, temperature, N,N‐diethylacrylamide, and alginate concentrations. The spectroscopic characteristic, thermal properties, and surface morphology of the copolymers were investigated by FTIR, 1H‐NMR, DSC/TGA, XRD, gel permeation chromatography, and SEM. Furthermore, low critical solution temperatures of Alg‐g‐PDEAAm copolymers were detected by UV spectroscopy. Swelling ratio of graft microspheres was carried out at 25, 32, and 37 °C, and microspheres were found exhibiting temperature‐responsive property. Cytotoxicity test indicated the Alg‐g‐PDEAAm copolymer and its microsphere were biocompatible. Therefore, based on the results the synthesized temperature‐responsive copolymer could be considered as a promising biomaterial. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46688.
Gelation studies on acrylic acid‐based hydrogels via in situ photo‐crosslinking and rheology
Authors: Magami Saminu M. , Williams Rhodri L.
Published: September 2018

The gelation characteristics of acrylic acid (AA)‐based hydrogels were investigated using real time in situ photocrosslinking and rheological measurements. The gel point and gelation times were established using Winter–Chambon criteria. Frequency independence of tan δ was observed in all cases, such that G′ and G″ scaled as ∼ωn. The Flory–Stockmayer theory was used alongside other indices in order to probe the gelation and the post‐gelation characteristics of the critical gels and the fully formed hydrogels. Network relaxation exponents (n) were influenced by the concentrations of AA and methylene bis‐acrylamide. The gel stiffness (S) decreased with an increase in the concentration of the monomer and of the concentration of the crosslinker, while network branching decreased (lower fractal dimensions) at the gel point. The conversion at the gel point was found to be iso‐conversion with respect to the intensity of the UV irradiance used in the photocrosslinking reactions (1–20 mW/cm2). Thus, network clusters and the crosslinking reaction mechanism were the same irrespective of radiation intensity, although the rates of the reactions were affected. Having sufficient amounts of reactive species at the time of cure drive the crosslinking reactions beyond the gel point to greater crosslink density and smaller mesh sizes. The effects of auto‐acceleration and free‐volume were observed and shown to have key effects on the gelation mechanisms and the branching topographies of the network, when the concentration of the known polyacrylamide medium were not controlled. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46691.
Optimization of PTFE/Cu/Al2O3 filled PMMA based composites on tribological properties using Taguchi design method
Authors: Gu Dapeng , Zhang Longxiao , Chen Suwen , Song Kefeng , Liu Shouyao
Published: September 2018

The filling combination of polytetrafluoroethylene (PTFE)/Cu/Al2O3 filled poly(methyl methacrylate) (PMMA) based composites aiming at low friction and wear is optimized based on L9(34) by Taguchi method. The worn morphologies of PMMA based composites are analyzed by scanning electron microscopy (SEM). The PTFE transfer film and the wear debris on the steel ball surface are analyzed by SEM and X‐ray spectroscopy. It is observed that the friction and wear of PMMA can be obviously decreased by filling with PTFE, Cu, and Al2O3. PTFE has the most significant but Cu has the negligibly smallest contribution on both the friction coefficient and the wear rate. The lower friction coefficient (<0.2) appears by the combination of the mass ratio of PTFE larger than about 4.5% and the mass ratio of Al2O3 lower than ∼7.5%. The lower wear rate (<5 × 10−5 mm3/Nm) appears by the combination of the mass ratio of PTFE larger than about 5% and the mass ratio of Al2O3 lower than ∼8%, but it does not include that PTFE is greater than about 8.5% and Al2O3 is less than about 1.5%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46705.
Mechanical and dynamic‐mechanical properties of silane‐treated graphite nanoplatelet/epoxy composites
Authors: Lavoratti Alessandra , Zattera Ademir José , Amico Sandro Campos
Published: September 2018

Thermoset resins are widely used for composite applications due to their excellent mechanical properties. To further enhance their performance, nanofillers such as graphite nanoplatelets (GrNP) have been used, and extra improvement may arrive from surface treating these fillers. This study aims to evaluate the influence of GrNP content and treatment with (3‐glycidyloxypropyl)trimethoxysilane and (3‐aminopropyl)triethoxysilane on curing behavior and mechanical and dynamic mechanical properties of GrNP/epoxy composites. Composites reinforced with 0.25 wt % GrNP displayed increased tensile strength by 11.8% compared to the neat resin. Addition of 0.5 wt % GrNP increased the glass transition temperature in 10°C compared to the neat polymer. Silane treated fillers showed an improvement in tensile strength and dynamic‐mechanical properties compared to the neat resin and non‐treated GrNP/epoxy composites at similar filler content. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46724.
The interaction of thin polyaniline films with various H‐phosphonates: Spectroscopy and quantum chemical calculations
Authors: Morávková Zuzana , Trchová Miroslava , Dybal Jiří , Bláha Michal , Stejskal Jaroslav
Published: September 2018

The conducting form of polyaniline (PANI) is formed by doping of non‐conducting PANI base usually by protonic acids. An alternative way of doping, consisting in an interaction via hydrogen bonding, has been previously proven for H‐phosphonates. In this study, PANI base films are exposed to various H‐phosphonates, changes in the structure of the films are analyzed by ultraviolet–visible, infrared, and Raman spectroscopies and spectroscopic data are compared with quantum chemical calculations. According to our results, the interaction of the PANI base films with H‐phosphonates is realized by hydrogen bonding between the imine nitrogen of PANI and the hydroxy group of the H‐phosphonate tautomeric form, i.e., phosphite. This is in the contrast to the PANI powders doped with H‐phosphonates where both interacting phosphite and non‐interacting H‐phosphonate forms were observed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46728.
Nanocomposites based on renewable thermoplastic polyurethane and chemically modified cellulose nanocrystals with improved mechanical properties
Authors: Prataviera Rogerio , Pollet Eric , Bretas Rosario E. S. , Avérous Luc , Lucas Alessandra A.
Published: September 2018

In this study, freeze‐dried cellulose nanocrystals (CNC) from eucalyptus, redispersed in dimethylformamide, is grafted with a polyurethane‐based dimer to improve the interaction with the matrix, a biobased thermoplastic polyurethane (TPU). Dimer grafting onto CNC is confirmed by Fourier transform infrared spectroscopy. Wide‐angle X‐rays diffraction and thermogravimetry indicate that neither the CNC crystal structure nor its thermal stability are altered, but its crystalline fraction decreased due to the presence of the dimer on the CNC surface. TPU/CNC nanocomposite films are obtained by solvent casting. Nanocomposites with nanofiller content below the theoretical percolation threshold (3.9 wt %) do not present significant changes in the mechanical properties. However, nanocomposites with 5.0 wt % of treated CNC shown good elongation and a Young modulus increase of 55 and 30% when compared with the neat TPU and untreated nanocomposites of same composition, respectively. In addition to that, the CNC addition increases the film opacity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46736.
In situ synthesis of PBO‐α‐(amino phthalocyanine copper) composite fiber with excellent UV‐resistance and tensile strength
Authors: Li J. , Wang W. , Zhao L. , Li S. , Yang L. , Huang Y.
Published: September 2018

The anti‐ultraviolet (UV) aging of the poly(p‐phenylene benzobisoxazole) (PBO) is very important and has been paid much attention recently. In this study, copolymerization of PBO and α‐amino phthalocyanine copper (α‐TDMACuPc) was carried out by in situ polymerization and the fiber was obtained by dry‐jet wet spinning in the liquid crystal state. Inducing of α‐TDMACuPc into PBO macromolecules improve the molecular network and enhanced the tensile strength of PBO fiber. With the capability of absorbing UV light into the PBO molecular chain, PBO copolymer fibers showed excellent anti‐UV aging performance and changed with the block structure. It is found that the retention of tensile strength after 100 h of UV irradiation was improved from 66.44% of PBO to 88.80% of PBO‐2.0 wt % α‐TDMACuPc fiber. Meanwhile, the degree of UV etching of the fibers decreased with the addition of α‐TDMACuPc. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46870.
Potential use of microcapsules in manufacture of fibrous products: A review
Authors: Petrulis Donatas , Petrulyte Salvinija
Published: September 2018

ABSTARCT

The present survey shows that microcapsules are used as effective tools for modification and functionalization of fibrous products. The core and shell materials of microcapsules can comprise various active ingredients in accordance with different requirements of final fibrous products. In this survey, the morphology, functional properties and added values of microcapsules, also such advanced types as nanocapsules, bi‐, multifunctional microcapsules, and their applications in smart and other modern products are described. Some relevant applications of microcapsules in industrial processes are briefly discussed. The techniques used to encapsulate the core ingredients are also overviewed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47066.