bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Applications of Carbon Nanomaterials in Diagnostics and Therapy
Authors: Loh Kian Ping , Ho Dean , Chiu Gigi Ngar Chee , Leong David Tai , Pastorin Giorgia , Chow Edward Kai‐Hua
Published: August 2018

Nanomaterials have the potential to improve how patients are clinically treated and diagnosed. While there are a number of nanomaterials that can be used toward improved drug delivery and imaging, how these nanomaterials confer an advantage over other nanomaterials, as well as current clinical approaches is often application or disease specific. How the unique properties of carbon nanomaterials, such as nanodiamonds, carbon nanotubes, carbon nanofibers, graphene, and graphene oxides, make them promising nanomaterials for a wide range of clinical applications are discussed herein, including treating chemoresistant cancer, enhancing magnetic resonance imaging, and improving tissue regeneration and stem cell banking, among others. Additionally, the strategies for further improving drug delivery and imaging by carbon nanomaterials are reviewed, such as inducing endothelial leakiness as well as applying artificial intelligence toward designing optimal nanoparticle‐based drug combination delivery. While the clinical application of carbon nanomaterials is still an emerging field of research, there is substantial preclinical evidence of the translational potential of carbon nanomaterials. Early clinically trial studies are highlighted, further supporting the use of carbon nanomaterials in clinical applications for both drug delivery and imaging.
Controlling Surface Charge Generated by Contact Electrification: Strategies and Applications
Authors: Chen Linfeng , Shi Qiongfeng , Sun Yajuan , Nguyen Trang , Lee Chengkuo , Soh Siowling
Published: August 2018

Contact electrification is the phenomenon in which charge is generated on the surfaces of materials after they come into contact. The surface charge generated has traditionally been known to cause a vast range of undesirable consequences in our lives and in industry; on the other hand, it can also give rise to many types of useful applications. In addition, there has been a lot of interest in recent years for fabricating devices and materials based on regulating a desired amount of surface charge. It is thus important to understand the general strategies for increasing, decreasing, or controlling the surface charge generated by contact electrification. Herein, the fundamental mechanisms for influencing the amount of charge generated, the methods used for implementing these mechanisms, and some of the recent interesting applications that require regulating the amount of surface charge generated by contact electrification, are briefly summarized.
Through Scalp and Skull NIR‐II Photothermal Therapy of Deep Orthotopic Brain Tumors with Precise Photoacoustic Imaging Guidance
Authors: Guo Bing , Sheng Zonghai , Hu Dehong , Liu Chengbo , Zheng Hairong , Liu Bin
Published: August 2018

Brain tumor is one of the most lethal cancers owing to the existence of blood–brain barrier and blood–brain tumor barrier as well as the lack of highly effective brain tumor treatment paradigms. Herein, cyclo(Arg‐Gly‐Asp‐D‐Phe‐Lys(mpa)) decorated biocompatible and photostable conjugated polymer nanoparticles with strong absorption in the second near‐infrared (NIR‐II) window are developed for precise photoacoustic imaging and spatiotemporal photothermal therapy of brain tumor through scalp and skull. Evidenced by the higher efficiency to penetrate scalp and skull for 1064 nm laser as compared to common 808 nm laser, NIR‐II brain‐tumor photothermal therapy is highly effective. In addition, via a real‐time photoacoustic imaging system, the nanoparticles assist clear pinpointing of glioma at a depth of almost 3 mm through scalp and skull with an ultrahigh signal‐to‐background ratio of 90. After spatiotemporal photothermal treatment, the tumor progression is effectively inhibited and the survival spans of mice are significantly extended. This study demonstrates that NIR‐II conjugated polymer nanoparticles are promising for precise imaging and treatment of brain tumors.
0.2 λ0 Thick Adaptive Retroreflector Made of Spin‐Locked Metasurface
Authors: Yan Libin , Zhu Weiming , Karim Muhammad Faeyz , Cai Hong , Gu Alex Yuandong , Shen Zhongxiang , Chong Peter Han Joo , Kwong Dim‐Lee , Qiu Cheng‐Wei , Liu Ai Qun
Published: August 2018

The metasurface concept is employed to planarize retroflectors by stacking two metasurfaces with separation that is two orders larger than the wavelength. Here, a retroreflective metasurface using subwavelength‐thick reconfigurable C‐shaped resonators (RCRs) is reported, which reduces the overall thickness from the previous record of 590 λ0 down to only 0.2 λ0. The geometry of RCRs could be in situ controlled to realize equal amplitude and phase modulation onto transverse magnetic (TM)‐polarized and transverse electric (TE)‐polarized incidences. With the phase gradient being engineered, an in‐plane momentum could be imparted to the incident wave, guaranteeing the spin state of the retro‐reflected wave identical to that of the incident light. Such spin‐locked metasurface is natively adaptive toward different incident angles to realize retroreflection by mechanically altering the geometry of RCRs. As a proof of concept, an ultrathin retroreflective metasurface is validated at 15 GHz, under various illumination angles at 10°, 12°, 15°, and 20°. Such adaptive spin‐locked metasurface could find promising applications in spin‐based optical devices, communication systems, remote sensing, RCS enhancement, and so on.
Stability of Halide Perovskite Solar Cell Devices: In Situ Observation of Oxygen Diffusion under Biasing
Authors: Jung Hee Joon , Kim Daehan , Kim Sungkyu , Park Joonsuk , Dravid Vinayak P. , Shin Byungha
Published: August 2018

Using in situ electrical biasing transmission electron microscopy, structural and chemical modification to n–i–p‐type MAPbI3 solar cells are examined with a TiO2 electron‐transporting layer caused by bias in the absence of other stimuli known to affect the physical integrity of MAPbI3 such as moisture, oxygen, light, and thermal stress. Electron energy loss spectroscopy (EELS) measurements reveal that oxygen ions are released from the TiO2 and migrate into the MAPbI3 under a forward bias. The injection of oxygen is accompanied by significant structural transformation; a single‐crystalline MAPbI3 grain becomes amorphous with the appearance of PbI2. Withdrawal of oxygen back to the TiO2, and some restoration of the crystallinity of the MAPbI3, is observed after the storage in dark under no bias. A subsequent application of a reverse bias further removes more oxygen ions from the MAPbI3. Light current–voltage measurements of perovskite solar cells exhibit poorer performance after elongated forward biasing; recovery of the performance, though not complete, is achieved by subsequently applying a negative bias. The results indicate negative impacts on the device performance caused by the oxygen migration to the MAPbI3 under a forward bias. This study identifies a new degradation mechanism intrinsic to n–i–p MAPbI3 devices with TiO2.
Protecting the Li‐Metal Anode in a Li–O2 Battery by using Boric Acid as an SEI‐Forming Additive
Authors: Huang Zhimei , Ren Jing , Zhang Wang , Xie Meilan , Li Yankai , Sun Dan , Shen Yue , Huang Yunhui
Published: August 2018

The Li–O2 battery (LOB) is considered as a promising next‐generation energy storage device because of its high theoretic specific energy. To make a practical rechargeable LOB, it is necessary to ensure the stability of the Li anode in an oxygen atmosphere, which is extremely challenging. In this work, an effective Li‐anode protection strategy is reported by using boric acid (BA) as a solid electrolyte interface (SEI) forming additive. With the assistance of BA, a continuous and compact SEI film is formed on the Li‐metal surface in an oxygen atmosphere, which can significantly reduce unwanted side reactions and suppress the growth of Li dendrites. Such an SEI film mainly consists of nanocrystalline lithium borates connected with amorphous borates, carbonates, fluorides, and some organic compounds. It is ionically conductive and mechanically stronger than conventional SEI layer in common Li‐metal‐based batteries. With these benefits, the cycle life of LOB is elongated more than sixfold.
E‐field Control of the RKKY Interaction in FeCoB/Ru/FeCoB/PMN‐PT (011) Multiferroic Heterostructures
Authors: Wang Xinjun , Yang Qu , Wang Lei , Zhou Ziyao , Min Tai , Liu Ming , Sun Nian X.
Published: August 2018

E‐field control of antiferromagnetic (AFM) orders is promising for the realization of fast, compact, and energy‐efficient AFM applications. However, as the AFM spins are strongly pinned, the E‐field control process is mainly based on the exchange bias regulation that usually confines at a low temperature. Here, a new magnetoelectric (ME) coupling mechanism for the modulation of AFM orders at room temperature is explored. Based on the FeCoB/Ru/FeCoB/(011) Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) synthetic antiferromagnetic (SAF) heterostructures, the external E‐field generates relative magnetization switching in the two ferromagnetic (FM) layers, leading the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction tuning. This voltage‐induced switching behavior can be repeated in a stable and reversible manner for various SAFs, which is a key challenge in the E‐field control of AFM coupling and is not resolved yet. The voltage‐induced RKKY interaction changes by analyzing the dynamic optical and acoustic modes is quantified, and with first‐principles calculations, it is found that the distortion of the Fermi surface by the lattice reconstruction is the key of the relative magnetization switching and RKKY interaction modulation. This voltage control of the RKKY interaction in ME heterostructures provides an easy way to achieve the next generation of AFM/FM spintronic applications.
Microstructure and Elastic Constants of Transition Metal Dichalcogenide Monolayers from Friction and Shear Force Microscopy
Authors: Xu Xiaomin , Schultz Thorsten , Qin Ziyu , Severin Nikolai , Haas Benedikt , Shen Sumin , Kirchhof Jan N. , Opitz Andreas , Koch Christoph T. , Bolotin Kirill , Rabe Jürgen P. , Eda Goki , Koch Norbert
Published: August 2018

Optical and electrical properties of 2D transition metal dichalcogenides (TMDCs) grown by chemical vapor deposition (CVD) are strongly determined by their microstructure. Consequently, the visualization of spatial structural variations is of paramount importance for future applications. This study demonstrates how grain boundaries, crystal orientation, and strain fields can unambiguously be identified with combined lateral force microscopy and transverse shear microscopy (TSM) for CVD‐grown tungsten disulfide (WS2) monolayers, on length scales that are relevant for optoelectronic applications. Further, angle‐dependent TSM measurements enable the fourth‐order elastic constants of monolayer WS2 to be acquired experimentally. The results facilitate high‐throughput and nondestructive microstructure visualization of monolayer TMDCs and insights into their elastic properties, thus providing an accessible tool to support the development of advanced optoelectronic devices based on such 2D semiconductors.
Triboelectric–Thermoelectric Hybrid Nanogenerator for Harvesting Energy from Ambient Environments
Authors: Wu Ying , Kuang Shuangyang , Li Huayang , Wang Hailu , Yang Rusen , Zhai Yuan , Zhu Guang , Wang Zhong Lin
Published: August 2018

Recently developed triboelectric nanogenerators (TENG) with advantages of a low fabrication cost, high output voltage, and high energy conversion efficiency have shown potential applications in harvesting ambient environment energy. However, the heat energy produced and wasted during the triboelectric energy generation process limits the output of TENG. One approach is to design TENG based on a noncontact mode to minimize the energy loss. The other approach is to scavenge the lost energy with a supplementary nanogenerator. In this work, triboelectric–thermoelectric hybrid nanogenerator (TTENG) is fabricated to harvest the energy from ambient environment and the thermal energy from the temperature difference induced by r‐TENG friction. At a rotation rate of 500 rpm, r‐TENG can produce a constant open‐circuit voltage (Voc) of 200 V and a short‐circuit current (Isc) of 0.06 mA. The thermoelectric nanogenerator (TMENG) with a size of 16 cm2 can produce a Voc of 0.2 V and an Isc of 20 mA. The experimental results show that the TTENG is a promising method to harvest the ambient mechanical energy.
Air‐Permeable and Washable Paper–Based Triboelectric Nanogenerator Based on Highly Flexible and Robust Paper Electrodes
Authors: Yang Wei , Cao Ran , Zhang Xiuling , Li Hui , Li Congju
Published: August 2018

The development of paper–based triboelectric nanogenerator (P‐TENG) has gained increasing importance because of the growing demand for the next‐generation wearable and portable electronics. However, currently, the limited washability and breathability of P‐TENG have largely hindered its further development in wearable applications. Here, an air‐permeable and washable P‐TENG is successfully fabricated using highly flexible and robust multiwalled carbon nanotubes coated air‐laid paper electrodes. The good air permeability of the P‐TENG makes it comfortable when directly laminated onto human skin for wearable applications. Furthermore, the P‐TENG not only exhibits excellent flexibility and mechanical stability, but also shows remarkable washing durability. The P‐TENG can be utilized as self‐charging systems to drive electronic devices or self‐powered active sensor to monitor human body motions. This work presents a new possibility of the integration of paper‐based energy‐harvesting devices with cloth/skin for building low‐cost, green, and multifunctional wearable devices and systems.
Breathable 3D Supercapacitors Based on Activated Carbon Fiber Veil
Authors: Shin Dongwoo , Shen Caiwei , Sanghadasa Mohan , Lin Liwei
Published: August 2018

For supercapacitors to become truly wearable to power various portable electronics, they must not only possess high power and energy density with long cycle life, but also provide comfort and durability. Here, a facile method of fabricating substrate‐free and freestanding breathable 3D supercapacitors using veil‐based electrodes with activated carbon fibers (ACFs) is reported. The conductive and high porous electrodes are lightweight, breathable, flexible, foldable, and tailorable with achieved high energy density of 5.52 Wh kg−1 and >86.6% capacitance retention over 10 000 charge–recharge cycles under various mechanical deformations such has folding, cutting, and compression. Different from the existing energy storage systems, the mechanically reliable supercapacitors can be integrated into parts of garments that are susceptible to a combination of anomalous mechanical deformations such as the inner elbow for 3D wearable energy storage applications.
Organocatalytic Asymmetric Formal Aza‐[3+3]Cyclo‐additions of 3‐Aminobenzofuran with α,β‐Unsaturated Aldehydes
Authors: Ding Xiang‐Feng , Su Ruo‐Heng , Yang Wu‐Lin , Deng Wei‐Ping
Published: August 2018

An organocatalytic asymmetric formal aza‐[3+3]cycloaddition of readily available N‐Tosyl‐3‐aminobenzofuran with α,β‐unsaturated aldehydes was developed for the first time. This method enables the facile synthesis of biologically active and synthetically challenging polysubstituted fused benzofuran derivatives bearing two stereocenters in high yields with excellent diastereo‐, and enantioselectivity (up to >20 : 1 dr, and >99% ee).

magnified image
Experimental investigation on activity of cumene hydroperoxide and selected ionic liquids in butadiene rubber vulcanization
Authors: Pingot Martyna , Szadkowski Bolesław , Zaborski Marian
Published: August 2018

In this work, cross‐linking at low temperature (90°C) of butadiene rubber (BR) using a vulcanizing system based on a hydroperoxide and ionic liquids (ILs) has been evaluated. Composites of BR with cumene hydroperoxide (CHP) and selected ILs have been prepared and tested. In order to elucidate the influence of novel systems on the cross‐linking as well as on the properties of the final product, BR composites have been characterized by different techniques, that is, rheometrical properties, cross‐linking density determination, as well as mechanical strength and weather aging resistance studies. Herein, the influence of weather aging on the properties of the samples is performed and further discussed. CHP and ILs were found to be an effective peroxide system, which enabled to decrease the energy consumption during vulcanization as well as the amount of applied CHP. Taking into account cross‐linking efficiency, system containing 1,3‐dimethylimidazolium methyl sulfate (IS), or tetrahexylammonium tetrafluoroborate (AB) seems to be the most active.
Implicit Bias Education and Emergency Medicine Training: Step One? Awareness
Authors: Zeidan Amy J. , Khatri Utsha G. , Aysola Jaya , Shofer Frances S. , Mamtani Mira , Scott Kevin R. , Conlon Lauren W. , Lopez Bernard L.
Published: August 2018

Objective

Prior research suggests that health care providers are susceptible to implicit biases, specifically prowhite biases, and that these may contribute to health care disparities by influencing physician behavior. Despite these findings, implicit bias training is not currently embedded into emergency medicine (EM) residency training and few studies exist that evaluate the effectiveness of implicit bias training on awareness during residency conference. We sought to conduct a mixed‐methods program evaluation of a formalized educational intervention targeted on the topic of implicit bias.

Methods

We used a design thinking framework to develop a curricular intervention. The intervention consisted of taking the Harvard Implicit Association Test (IAT) on race to introduce the concept of implicit bias, followed by a facilitated discussion to explore participant's perceptions on whether implicit bias may lead to variations in care. The facilitated discussion was audio recorded, transcribed, and coded for emerging themes. An online survey assessed participant awareness of these topics before and after the intervention and was analyzed using paired t‐tests.

Results

After the intervention, participant's awareness of their individual implicit biases increased by 33.3% (p = 0.003) and their awareness of how their IAT results influences how they deliver care to patients increased by 9.1% (p = 0.03). Emerging themes included skepticism of the implicit bias test results with the desire to have “neutral” results, acknowledgment that pattern recognition may lead to “blind spots” in care, recognition that bias exists on a personal and systemic level, and interest in regular educational interventions to address implicit bias.

Conclusions

This novel educational intervention on implicit bias resulted in improvement in participants’ awareness of their implicit biases and how it may affect their patient care. Our intervention can serve as a model for other residency programs to develop and implement an intervention to create awareness of implicit bias and its potential impact on patient care.
Faculty Development Program for Emergency Medicine Physicians in India: A Pilot Program
Authors: Douglass Katherine , Williams Amanda
Published: August 2018

Background

The specialty of emergency medicine (EM) is developing worldwide at a rapid pace. While more and more postgraduate training programs are developing, a major gap persists in numbers and availability of well‐trained academic faculty members. This article describes a pilot faculty development program (FDP) aimed to develop advanced academic skills among a group of EM physicians in India.

Methods

A FDP was developed with foundations in adult learning principles, using a combined approach of online and in‐person didactic sessions. Specific expectations were established regarding academic contributions to participants’ home institutions. Mentorship relationships were established between academic emergency physicians and program participants.

Results

A 12‐month pilot program was implemented across four EM training programs in India. Nine faculty members completed the full requirements of the pilot program, eight of whom have continued to work as academic faculty members in EM training programs. Academic productivity among these physicians since completion of the program includes 11 abstract publications, six peer‐reviewed articles, and 71 mentorship relationships. Program challenges included participant attrition, connectivity issues, and low rates of completion of evaluation requirements by both participants and mentors.

Conclusions

This pilot program in faculty development provides a foundation from which further programs may be developed in the international sector. Effective faculty development is a cornerstone of good academic medicine, which is of particular relevance, importance, and challenge in the global context of a developing specialty.
Association between FTO gene polymorphism and excess body weight in women from before to after pregnancy: A cohort study
Authors: Kroll Caroline , de França Paulo Henrique Condeixa , Mastroeni Marco Fabio
Published: August 2018

Objective

The aim of this study was to examine the influence of the FTO‐rs9939609 polymorphism on excess body weight in women during the reproductive transition from pre‐ to post‐pregnancy.

Methods

This was a prospective cohort study covering a period extending from before pregnancy to 2 and 4 years after pregnancy. A total of 435 women were first included in the study and, at last follow‐up, 220 of them continued to participate in the study. The FTO‐rs9939609 polymorphism was analyzed by the polymerase chain reaction/ restriction fragment length polymorphism (PCR/RFLP) method.

Results

The FTO‐rs9939609 polymorphism was associated with increasing weight and body mass index (BMI) during the follow‐up period. Women carrying at least 1 risk allele (A) were significantly heavier (P < .05, up to 4.24 kg) and had a 1.30 kg/m2 higher BMI. Although the AA genotype was significantly associated with a greater risk compared to the wild‐type genotype in the cross‐sectional analysis, the results did not differ significantly in the longitudinal analysis (AA genotype, β = 1.20, 95% CI 0.85‐1.68), even after adjustment for pre‐pregnancy age, smoking before pregnancy, parity at pregnancy, and gestational weight gain.

Conclusions

The FTO‐rs9939609 polymorphism was associated with increased weight and BMI in mothers before and after pregnancy. However, we found no significant effect of the polymorphism on excess body weight of women during the reproductive trajectory.
Intergenerational changes in limb circumferences in children and adolescents aged 3‐18 from Kraków (Poland) from 1983 to 2010
Authors: Kryst Łukasz , Woronkowicz Agnieszka , Kowal Małgorzata , Sobiecki Jan
Published: August 2018

Objectives

Measurements of body circumferences are often used in anthropology. The research on this topic, however, rarely concerns limb girths or secular trends. The main aim of this study was to investigate the occurrence of secular trends in selected limb circumferences among children and adolescents.

Methods

The research was based on measurements from two cross‐sectional studies carried out in 1983 and 2010 with children and adolescents aged 3‐18 from Krakow, Poland. The circumferences of the arm, forearm, thigh and calf, as well as the sum of circumferences and selected indicators, were analyzed. The series were compared using the two‐way anova test.

Results

In most age groups of both sexes, a positive secular trend was observed for the majority of studied traits. The exception was the thigh circumference, for which, among girls, measurements in both series were similar, and negative intergenerational changes were recorded in the youngest age groups of both sexes as well as among the oldest girls. Most observed discrepancies were statistically significant in pre‐school children and adolescents.

Conclusions

The presence of positive secular trends shows that limb circumferences were increasing in subsequent generations, especially in boys. Contemporary girls, particularly in the older age groups, were more determined to have a slim figure and practiced conscious weight control. Summarizing, observed tendencies resulted from the improvement of socio‐economic conditions, but were also related to the low level of physical activity.
Organic Phototransistors Based on Self‐Assembled Microwires of n‐Type Distyrylbenzene Derivative
Authors: Lee Yoon Ho , Shin Dong‐Seon , Kim Dong Yeong , Nam Dongsik , Choe Wonyoung , Hong Sung You , Oh Joon Hak
Published: August 2018

Molecular design and crystallinity control are important issues for the development of high‐performance organic optoelectronic devices. Here, a highly photo‐responsive n‐type organic small molecular semiconductor, (2Z,2′Z)‐3,3′‐(2,5‐dimethoxy‐1,4‐phenylene)bis(2‐(3,5‐bis(trifluoro‐methyl)phenyl)acrylonitrile) (DM‐R), was synthesized and the photoelectronic properties of self‐assembled DM‐R microwire organic phototransistors (MW‐OPTs) were studied. Significant enhancement in the electron mobility (μe) of MW‐OPTs (μe: 0.16 cm2 V−1 s−1) was observed as compared to thin‐film‐OPTs (μe: 2.7×10−3 cm2 V−1 s−1), most likely due to the single‐crystalline nature of the self‐assembled MWs. Moreover, the photoresponsivity of MW‐OPTs showed 23.53 (A W−1), which was 130 times higher than that of thin‐film OPTs (0.18 A W−1). Furthermore, the MW‐OPTs exhibited stable photoswitching properties and a faster charge accumulation/release rate than those of thin‐film OPTs. The results obtained herein demonstrate a facile solution‐based approach for the fabrication of high‐performance n‐type organic MW‐OPTs and provide a systematic analysis platform of the photo‐generated charge carrier dynamics.
Brief communication: Test of a method to identify double‐zonal osteon in polarized light microscopy
Authors: Raguin Emeline , Streeter Margaret A.
Published: August 2018

Objectives

Double‐zonal osteons (DZ) have been of interest in paleopathological research because they might be linked to physiological pathology. DZ are thought to be evidence of arrested osteon formation with a brief but abrupt increase in mineralization of lamellae occurring during bone remodeling. Originally identified from microradiographs as hypermineralized rings, recent studies have identified DZ from linear polarized light microscopy (PLM). However, PLM does not guarantee the adequate detection of DZ since PLM captures bone birefringence and not hyper‐mineralization. Scanning electron microscopy with backscatter electrons (BSE‐SEM) allows observation of DZ by detecting differences in mineralization. The purpose of this study is to investigate whether DZ, as identified by BSE‐SEM, can indeed be identified with PLM.

Materials and methods

The sample consists of an archaeological collection of adult midshaft femurs (n = 30) from St. Matthew cemetery, Quebec City (1771–1860). DZ were identified and counted independently with PLM and BSE‐SEM for the same sections. Results from both methods were compared.

Results

Chi‐square test shows that there was no significant difference between the two methods (p = 0.404). No significant bias was found on Bland‐Altman analysis and Cohen's kappa shows a substantial agreement between the two methods (Κ = 0.66). PLM shows a good accuracy (sensitivity 79%, specificity 99.4%) and reliability (Positive Predictive Value: 86.71%; Negative Predictive Value: 99.45%).

Discussion

These findings indicate that the two methods are interchangeable. PLM, using our proposed protocol, is reliable to accurately identify DZ. We discuss how PLM and BSE‐SEM that measure different features of the bone tissue can converge on the identification of DZ.
Technical note: The use of 3D printing in dental anthropology collections
Authors: Fiorenza Luca , Yong Robin , Ranjitkar Sarbin , Hughes Toby , Quayle Michelle , McMenamin Paul G. , Kaidonis John , Townsend Grant C. , Adams Justin W.
Published: August 2018

Objectives

Rapid prototyping (RP) technology is becoming more affordable, faster, and is now capable of building models with a high resolution and accuracy. Due to technological limitations, 3D printing in biological anthropology has been mostly limited to museum displays and forensic reconstructions. In this study, we compared the accuracy of different 3D printers to establish whether RP can be used effectively to reproduce anthropological dental collections, potentially replacing access to oftentimes fragile and irreplaceable original material.

Methods

We digitized specimens from the Yuendumu collection of Australian Aboriginal dental casts using a high‐resolution white‐light scanning system and reproduced them using four different 3D printing technologies: stereolithography (SLA); fused deposition modeling (FDM); binder‐jetting; and material‐jetting. We compared the deviations between the original 3D surface models with 3D print scans using color maps generated from a 3D metric deviation analysis.

Results

The 3D printed models reproduced both the detail and discrete morphology of the scanned dental casts. The results of the metric deviation analysis demonstrate that all 3D print models were accurate, with only a few small areas of high deviations. The material‐jetting and SLA printers were found to perform better than the other two printing machines.

Conclusions

The quality of current commercial 3D printers has reached a good level of accuracy and detail reproduction. However, the costs and printing times limit its application to produce large sample numbers for use in most anthropological studies. Nonetheless, RP offers a viable option to preserve numerically constraint fragile skeletal and dental material in paleoanthropological collections.
PNA‐Hybridsequenzen als Erkennungseinheiten in SNARE‐Protein‐analogen Peptiden
Authors: Hubrich Barbara E. , Kumar Pawan , Neitz Hermann , Grunwald Matthias , Grothe Tobias , Walla Peter Jomo , Jahn Reinhard , Diederichsen Ulf
Published: August 2018

Die Fusion von Membranen ist ein grundlegender Prozess in der Natur, der oft durch die spezifische Interaktion von SNARE‐Proteinen herbeigeführt wird. SNARE‐Modellsysteme, in denen die SNARE‐Domänen durch kleine artifizielle Einheiten ersetzt sind, stellen wertvolle Werkzeuge dar, um die Membranfusion in vitro zu untersuchen. Hier werden Synthese und Analyse von SNARE‐Modellpeptiden vorgestellt, die eine aus zwei unterschiedlichen Peptidnukleinsäure(PNA)‐Topologien zusammengesetzte Erkennungseinheit besitzen. Diese neuartige Erkennungseinheit wurde entwickelt, um den Reißverschluss‐Mechanismus der SNARE‐Proteine nachzustellen, der für die Einleitung der SNARE‐Protein vermittelten Membranfusion verantwortlich gemacht wird. Die Erkennungseinheit besteht aus N‐(2‐Aminoethyl)glycin‐PNA (Aeg‐PNA) und Alanyl‐PNA, die beide ihren entsprechend komplementären Strang erkennen können, allerdings unterschiedliche Duplextopologien und Duplexbildungskinetiken aufweisen. Neben der Charakterisierung der Duplexbildung der PNA‐Hybridoligomere wird auch die Fusogenität der Modellpeptide anhand von Lipidmischungsexperimenten untersucht und es wird gezeigt, dass die Modellpeptide Fusion induzieren. Unerwartet war, dass Peptide mit einer Erkennungseinheit von nur fünf Aeg‐PNA‐Einheiten bereits die Fusion von Liposomen induzieren und sich dabei bislang sogar als am effizientesten erwiesen haben.
Infinite Ansammlungen gefalteter Proteine im Kontext von Evolution, Krankheiten und Proteinentwicklung
Authors: Garcia‐Seisdedos Hector , Villegas José A. , Levy Emmanuel D.
Published: August 2018

Mutationen und Veränderungen in der Umgebung eines Proteins sind bekannt dafür, potenziell Fehlfaltungen und Aggregation wie Amyloidbildung zu verursachen. Derartige Einflüsse können allerdings auch neue Interaktionen bewirken, die zur Polymerisation gefalteter Proteine führen. Im Unterschied zur Aggregation können solche Vorgänge aber auch ohne Fehlfaltungen ablaufen. Um diesen Unterschied hervorzuheben, bezeichnen wir sie als Agglomeration. Dieser Begriff umfasst die amorphe Zusammenlagerung gefalteter Proteine wie auch deren ein‐, zwei‐ und dreidimensionale Polymerisation. Wir möchten auf die bemerkenswerte Fähigkeit symmetrischer Homooligomere hinweisen, sogar infolge einzelner Oberflächenmutationen zu agglomerieren. Wir erörtern des Weiteren die ambivalente Natur dieser Eigenschaft: Durch Agglomeration entstandene anomale Ansammlungen können einerseits zum Entstehen von Krankheiten beitragen, sind aber andererseits auch für die zelluläre Anpassung verantwortlich und können zudem für das zielgerichtete Design neuer Biomaterialien genutzt werden.
Selektive Aktivierung der humanen caseinolytischen Protease P (ClpP)
Authors: Stahl Matthias , Korotkov Vadim S. , Balogh Dóra , Kick Leonhard M. , Gersch Malte , Pahl Axel , Kielkowski Pavel , Richter Klaus , Schneider Sabine , Sieber Stephan A.
Published: August 2018

Die caseinolytische Protease P (ClpP) ist die proteolytische Komponente des Protein‐Abbau‐Komplexes ClpXP. Ihre genaue Funktion und Regulation sind größtenteils unerforscht. Hier stellen wir eine niedermolekulare Verbindung (D9) vor, die durch Nachahmung des natürlichen Chaperons ClpX als potenter und Spezies‐selektiver Aktivator der humanen ClpP (hClpP) wirkt. Struktur‐Aktivitäts‐Studien hoben die Wichtigkeit eines halogenierten Benzyl‐Motivs innerhalb von D9 hervor. Dieses interagiert mit einem einzigartigen aromatischen Aminosäure‐Netzwerk in hClpP. Mutations‐ und Strukturstudien legen nahe, dass dieses sogenannte YYW‐Motiv die hClpP‐Aktivität streng kontrolliert und den Substratumsatz durch Interaktion mit passenden Liganden reguliert. Ferner ist dieses Motiv besonders für ClpP höherer Organismen charakteristisch und existiert nicht in getesteten bakteriellen Homologen. Dies erlaubt eine Spezies‐selektive Analyse, womit D9 ein vielseitiges Werkzeug für die Untersuchung von mechanistischen Eigenschaften der hClpP werden kann.
Can a Ketone Be More Reactive than an Aldehyde? Catalytic Asymmetric Synthesis of Substituted Tetrahydrofurans
Authors: Lee Sunggi , Bae Han Yong , List Benjamin
Published: August 2018

O‐heterocycles bearing tetrasubstituted stereogenic centers are prepared via catalytic chemo‐ and enantioselective nucleophilic additions to ketoaldehydes, in which the ketone reacts preferentially over the aldehyde. Five‐ and six‐membered rings with both aromatic and aliphatic substituents, as well as an alkynyl substituent, are obtained. Moreover, 2,2,5‐trisubstituted and 2,2,5,5‐tetrasubstituted tetrahydrofurans are synthesized with excellent stereoselectivities. Additionally, the synthetic utility of the described method is demonstrated with a three‐step synthesis of the side chain of anhydroharringtonine.
Selective Activation of Human Caseinolytic Protease P (ClpP)
Authors: Stahl Matthias , Korotkov Vadim S. , Balogh Dóra , Kick Leonhard M. , Gersch Malte , Pahl Axel , Kielkowski Pavel , Richter Klaus , Schneider Sabine , Sieber Stephan A.
Published: August 2018

Caseinolytic protease P (ClpP) is the proteolytic component of the ClpXP protein degradation complex. Eukaryotic ClpP was recently found to act within the mitochondria‐specific unfolded protein response (UPRmt). However, its detailed function and dedicated regulation remain largely unexplored. A small molecule (D9) acts as a potent and species‐selective activator of human ClpP (hClpP) by mimicking the natural chaperone ClpX. Structure–activity relationship studies highlight the importance of a halogenated benzyl motif within D9 that interacts with a unique aromatic amino acid network in hClpP. Mutational and structural studies suggest that this YYW motif tightly controls hClpP activity and regulates substrate turnover by interaction with cognate ligands. This signature motif is unique to ClpP from higher organisms and does not exist in tested bacterial homologues, allowing a species‐selective analysis. Thus, D9 is a versatile tool to analyze mechanistic features of hClpP.
Study of low‐cost and high‐performance biomass activated carbon for phenol removal from wastewater: Kinetics, isotherms, and thermodynamics
Authors: Li Xiaolei , Guo Feiqiang , Jiang Xiaochen , Zhao Xingmin , Peng Kuangye , Guo Chenglong
Published: August 2018

In this study, biomass activated carbon (AC) has been prepared by CO2 activation from pine sawdust, and its ability to extract a model compound (phenol) from solutions was studied to estimate its purifying capacity on wastewater. Ninety minutes and 800 °C were selected as the proper conditions on account of both good pore distribution and feasible yield. Thermogravimetric analysis, N2 adsorption/desorption, scanning electron microscope (SEM), and X‐ray diffractometer analyses were used to characterize the surface and textural properties. The contributions of CO2 activation to the evolution of porous structures, especially to the formation of micropores, were originated from the reaction of CO2–C at above 800 °C and the oxidizing effect on the residual volatiles after carbonization to reopen the blocked pores. The best fitted pseudo‐second‐order kinetic model, Langmuir and Temkin isotherm models, suggested that chemisorption might be the rate‐limiting step of the homogeneous and monolayer adsorption process. The diffusion of phenol into PS‐800‐90 was mainly controlled by film diffusion and intraparticle diffusion. The maximum monolayer capacity (qm) of PS‐800‐90 obtained by Langmuir model was 161.03 mg/g at 298 K. Spontaneous (ΔGo < 0) and exothermic (ΔHo < 0) nature of the adsorption process was obtained through thermodynamic study, indicating that the increase of temperature was unfavorable to adsorption. The Fourier transform infrared spectroscopy analysis of the fresh and spent AC coupled with pH experiments revealed that the main adsorption could be originated from H‐bonding and π–π stacking interactions between AC and phenol. The adherence of phenol on the surface of AC was also proved by SEM‐Energy Dispersive Spectrometer (EDS) results.
Thermodynamic analysis of a mechanical vapor recompression evaporation system coupled with crystalization for salt separation
Authors: Kang Ruo‐Yu , Yan Jian‐Min , Xiao Wen‐De
Published: August 2018

Currently, the mechanical vapor recompression (MVR) system is extensively used for single salt separation, but the relevant research on mixed salt system treatment is still in initial stage. As a very common salt solution system, sodium chloride–potassium chloride–water system can be readily found in many processes. It is no doubt of great significance to separate their crystals from the mixed solution in an efficient and environmentally friendly way. Therefore, with the aid of Aspen Plus software, this study aims to design an MVR evaporation system capable of treating sodium chloride–potassium chloride–water system. Subsequently, the analysis about the start‐up schemes and some influencing factors in the steady‐state operation are carried out, so as to provide some guidance and reference for the future technical route to separate mixed salt system with low energy consumption.
Thermal, dielectric, and mechanical properties of h‐BN‐filled PTFE composites
Authors: Zimmermann‐Ptacek Johanna , Muggli Mark , Wildhack Stefanie , Hintzer Klaus , Gerdes Thorsten , Willert‐Porada Monika , Moos Ralf
Published: August 2018

In order to obtain materials for improved printed circuit boards (PCBs) with high thermal conductivity and low dielectric losses, hexagonal boron nitride (h‐BN) was incorporated into a polytetrafluoroethylene (PTFE) matrix. The filler loading in the composite was varied up to a filler volume content of 50%. Thermal conductivity and coefficient of thermal expansion (CTE) were investigated with respect to filler orientation. Further dielectric and mechanical properties were investigated. The incorporation of h‐BN improved the heat transport significantly, while the loss factor decreased. Fillers with a higher aspect ratio have a greater effect on increasing thermal conductivity. For a filler volume loading of 30%, the in‐plane thermal conductivity was up to 14 times higher than the thermal conductivity of the matrix, while the loss factor decreased slightly. The permittivity increased with the increasing filler volume content, while the CTE also decreased. Though the filler affects the mechanical properties negatively, 40% of the tensile strength could be maintained if a filler volume content of 30% is not exceeded. Such compositions may be used as raw materials for future printed circuit boards. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46859.
Operational maps between molecular properties and environmental stress cracking resistance
Authors: Sardashti P. , Stewart K. M. E. , Polak M. , Tzoganakis C. , Penlidis A.
Published: August 2018

Environmental stress cracking (ESC) is one of the main failure mechanisms involved in polymer fractures. This work focuses on the ESC resistance (ESCR) of polyethylene (PE) in which ESC occurs through a slow crack growth mechanism. To predict the ESCR of PE, it is necessary to fully understand the molecular structure of the resin. This work demonstrates the relationships between molecular structure characteristics and material responses based on experimental characterization and published literature trends. Relationships between ESCR, molecular weight, percentage crystallinity, and density were used to create ESCR and molecular structure maps, which can be used to improve the development of PE resins with a desirable (better/higher) ESCR. These maps along with a logical flow chart offer practical prescriptions and describe pathways toward the development of PE with a desirable ESCR. In addition, this work presents case studies that demonstrate the effectiveness of this approach. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47006.
mPEG–NHS carbonates: Effect of alkyl spacers on the reactivity: Kinetic and mechanistic insights
Authors: Vaillard Victoria A. , Menegon Malen , Neuman Nicolás I. , Vaillard Santiago E.
Published: August 2018

Nowadays, the chemical conjugation to mPEG, also known as PEGylation, is a well‐recognized technology used to improve the pharmaceutical properties of the therapeutic proteins. Over the last 20 years, more than 10 PEGylated macromolecules reached the market with tremendous success, whereas various other bioconjugates are under advanced clinical trials. mPEG–N‐hydroxysuccinimidyl carbonate is an important reagent of widespread application for the PEGylation of biomacromolecules. One of the most important challenges in this technology is the development of more selective PEGylation reagents aimed to provide more consistent polymer–protein conjugates. One approach followed to improve the selectivity of PEGylation reagents is the design of less reactive derivatives, for example, by incorporation of alkyl spacers between the polymer chain and the terminal reactive group. In this work, we prepared a family of mPEG–N‐hydroxysuccinimidyl carbonates bearing spacers of up to 6 carbon atoms. The kinetics of hydrolysis of the carbonates was studied under different experimental conditions, as a straight measure of the influence of the length of the spacer on the reactivity. By DFT calculations, we propose a detailed mechanism for the hydrolysis reaction. The influence of the length of alkyl spacer on the reactivity of the carbonates and related esters is studied and discussed in detail. Finally, to further evaluate the reactivity, selected N‐hydroxysuccinimidyl carbonates were studied in the conjugation reaction of bovine lactoferrin. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47028.
SSR markers for Filago subg. Filago (Gnaphalieae: Asteraceae) and cross‐amplification in three other subgenera
Authors: Gutiérrez‐Larruscain David , Malvar Ferreras Teresa , Martínez‐Ortega M. Montserrat , Rico Enrique , Andrés‐Sánchez Santiago
Published: August 2018

Premise of the Study

Microsatellite primers were developed for the first time in the genus Filago (Gnaphalieae: Asteraceae). These markers will facilitate low‐scale phylogenetic, phylogeographic, and population genetic studies within the genus Filago.

Methods and Results

Ten pairs of polymorphic microsatellite primers (as well as five pairs of monomorphic primers) were identified and optimized on two species of Filago (F. gaditana and F. carpetana) using a microsatellite‐enrichment library method and 454 GS‐FLX technique. The polymorphic primers amplified tri‐ to hexanucleotide repeats and showed one to six alleles per locus for both species. Transferability was performed in 29 samples corresponding to nine representative species of Filago.

Conclusions

The results indicate the utility of the newly developed markers, which will be useful to delve into the phylogenetic relationships among the taxa within Filago. These microsatellites will enable studies of phylogeographic, reproductive, and genetic variation.
Development of EST‐SSR markers for Pluchea indica (Asteraceae) and cross‐amplification in related species
Authors: Yang Yi , Huang Sixin , Wang Yanling , Gui Lingjian , Liu Yiran , Huang Xiaomei , Chen Guoqingzi , Tan Fengxiao , Wang Jianwu
Published: August 2018

Premise of the Study

Expressed sequence tag–simple sequence repeat (EST‐SSR) markers were developed for Pluchea indica, a traditional medicinal species widespread along the tropical coastlines of Asia and northern Australia.

Methods and Results

Based on transcriptome data for P. indica, a total of 40 primer pairs were initially designed and tested, of which 17 were successfully amplified and showed clear polymorphism. For these SSR loci, one to nine alleles per locus were identified. The levels of observed and expected heterozygosity ranged from 0 to 0.9 and 0 to 0.831, respectively. Furthermore, 16, 17, and 12 loci were successfully amplified in three congeneric species, P. eupatorioides, P. pteropoda, and P. sagittalis, respectively.

Conclusions

The SSR markers described here may be useful for further investigation of the population genetics of P. indica and related species.