bluuebunny/crossref_metadata_2025 huggingface dataset:
The Outcome of Dopamine Dysregulation Syndrome in Parkinson's Disease: A Retrospective Postmortem Study
Authors: Barbosa Pedro , Djamshidian Atbin , Lees Andrew J. , Warner Thomas T.
Published: August 2018

Introduction

We have performed a retrospective analysis of the frequency and relation to treatment of dopamine dysregulation syndrome (DDS) using the Queen Square Brain Bank (QSBB) database.

Methods

A search of the QSBB database for consecutive cases donated between 2005 and 2016 with a pathological diagnosis of Parkinson's disease was performed.

Results

DDS was present in 8.8% of cases, was more prevalent in males, and was associated with younger age of onset, longer disease duration, and more dopa‐induced dyskinesias. Treatment approaches for DDS included: reduction of levodopa, reduction/cessation of dopamine agonist (DA), and initiation of infusion therapies. DDS had completely resolved in just over half the patients. DA peak l‐dopa equivalent daily dose (LEDD) was higher in patients who failed to achieve remission.

Conclusion

This is the first study to provide data on the course of DDS until death. Treatment strategies consisted mainly of reduction of dopaminergic treatment, and, despite the majority of patients showing some improvement, half remained symptomatic. Successful treatment was associated with a lower l‐dopa dosage at death.
Understanding, Impact, and Communication of “Off” Periods in Parkinson's Disease: A Scoping Review
Authors: Rastgardani Tara , Armstrong Melissa J. , Gagliardi Anna R. , Marras Connie
Published: August 2018

Background

Off periods are a common and disabling symptom of Parkinson's disease. We reviewed published research on understanding, impact, and communication regarding off periods to identify issues warranting further research.

Methods

We performed a scoping review, searching MEDLINE, EMBASE, Cochrane Library, CINAHL, and PsycINFO from 2006 to January 2018 for studies examining the impact of, understanding of, or communication about off periods.

Results

Twenty‐six papers met eligibility criteria. Twenty‐three studies evaluated the impact or experience of off periods in patients, three evaluated the impact upon carepartners, two papers addressed understanding of off periods, one study evaluated communication about off periods, and three studies evaluated a facilitator of communication about off periods. The findings indicate that (1) off periods are among the most troublesome symptoms to patients and that their impact on activities is broad; (2) the understanding of off periods by patients, carepartners, and nurses may be suboptimal; and (3) questionnaires hold promise as a mechanism for facilitating communication given the findings that they may enhance the detection of off periods and are rated as useful by physicians. No studies evaluated interventions to promote knowledge about off periods, and no studies identified barriers of communication about off periods.

Conclusions

There is a paucity of knowledge regarding the lived experiences of off periods, particularly for carepartners. Additionally, little knowledge exists in the literature regarding understanding of and communication about off periods between patients or carepartners and treating physicians. Further research is required to explore these issues to ultimately improve the treatment of off periods.
Search for altered imprinting marks in Mayer–Rokitansky–Küster–Hauser patients
Authors: Eggermann Thomas , Ledig Susanne , Begemann Matthias , Elbracht Miriam , Kurth Ingo , Wieacker Peter
Published: August 2018

Background

Mayer–Rokitansky–Küster–Hauser syndrome (MRKH) is the second most common cause of primary amenorrhea and characterized by absence of the uterus and the upper part of the vagina. The etiology of MRKH is mainly unknown but a contribution of genomic alterations is probable. A molecular disturbance so far neglected in MRKH research is aberrant methylation at imprinted loci. In fact, MRKH has been reported in patients with the imprinting disorder Silver–Russell syndrome.

Methods

We report on a rare patient with MRKH and SRS due to an ICR1 hypomethylation in 11p15.5. On the basis of this observation we screened a large cohort of MRKH patients (n > 100) for aberrant methylation at nine imprinted loci.

Results

We failed to detect any epimutation, thus we conclude that imprinting defects at least at the currently known disease‐relevant imprinted loci do not contribute to the isolated MRKH phenotype. However, it cannot be excluded that altered methylation marks at other loci are involved in the etiology of MRKH.

Conclusion

The molecular basis for MRKH remains unclear in the majority of patients, but future studies on the association between MRKH and ICR1 hypomethylation/SRS will to enlighten the role of epigenetics in the etiology of MRKH.
A dual band stub‐loaded AMC design for the gain enhancement of a planar monopole antenna
Authors: Paracha Kashif Nisar , Abdul Rahim Sharul K. , Soh P. J. , Chatha Hassan T. , Misran Misran H. , Lokman Abdul Halim
Published: August 2018

A dual band stub‐loaded artificial magnetic conductor (AMC) structure to enhance the gain of a dual band monopole is presented. Designed for operation in the 2.4 and 5 GHz WLAN bands, the AMC unit cell is intended to be capable of independently tuning the upper (5 GHz) band by varying the stub length of the structure. To assess the effectiveness of the AMC plane, it is integrated underneath a coplanar waveguide (CPW)‐fed planar monopole antenna. Both structures are designed and fabricated on a FR4 substrate. The unit cell is first multiplied into a 5 x 5 array to form the AMC plane, which acts as a reflector to the monopole antenna. Measurements indicated values of 6.76 dBi (at 2.4 GHz) in band‐I, 6.5 dBi (at 3.53 GHz) in band‐II, and finally 7.26 dBi (at 4.85 GHz) in band‐III. It is also observed that the measured antenna gain is improved to 7.26 dBi from 4.2 dBi at 4.85 GHz with reduced SAR values. Moreover, its overall size of 70 × 70 × 10.76 mm3 (0.45λ0 × 0.45λ0 × 0.07λ0) validated the compactness in comparison with other similar structures, with reasonable realized gain.
Q/V band LNA for satellite on‐board space applications using a 70 nanometers GaAs mHEMT commercial technology
Authors: Ciccognani Walter , Longhi Patrick E. , Colangeli Sergio , Limiti Ernesto ,   Senior Member IEEE
Published: August 2018

Designing wideband low noise amplifiers (LNAs) at millimeter wave frequencies (>30 GHz) is rather challenging due to trade‐offs that need to be achieved between often contrasting goals such as noise figure, gain, impedance matching, stability, DC power consumption, and chip size. In this paper, a low noise design procedure at 50 GHz is presented, proving the feasibility of a 2 dB Noise Figure LNA at Q/V band. Such performance is enabling for future (but imminent) satellite communication systems operating in the 47‐52 GHz frequency band. Repeatability and reliability are key requirements for satellite operations and therefore an Industrial Grade—Space Qualified technology has been selected.
Behavior modeling of passive intermodulation distortion with multiple nonlinear sources
Authors: Jin Qiuyan , Gao Jinchun , Wu Yongle , Xie Gang
Published: August 2018

A modified passive intermodulation (PIM) model with multiple nonlinear sources and lossy transmission is developed to evaluate the reflected passive intermodulation products (PIMP) in case of series connection. Equivalent circuit models are proposed for demonstrating the effect of length between nonlinear sources and number of connections on the PIM behaviors, followed by some experimental validation. The measurement results agree well with the theoretical calculations and circuit simulations, having a mean difference within 0.5 dB.
Design and realization of quasi Yagi antenna for indoor application with 3D printing technology
Authors: Belen Mehmet A. , Mahouti Peyman
Published: August 2018

With the advances in the extrusion depositing base three‐dimensional (3D) printing technology and decreases in their costs, these technologies are being used in many fields for fast and low cost prototyping means. One of these applications is manufacturing of microwave circuits. Herein, design and realization of quasi Yagi antenna for indoor application with 3D printing technology is presented. First, design of a wide band microstrip quasi Yagi antenna consists of a dipole fed by a coplanar strip line, a rectangular patch, and a ground reflector is studied. The size of the antenna is reduced by using a half bowtie shaped dipole and reflector. The studied microstrip quasi Yagi antenna is aimed to operate within the operation frequency range of 670–3000 MHz. Then for experimental results, the designed antenna is fabricated by using a 3D printer with poly(lactide acid) material. From observing the experiment results it can be concluded that 3D printed antenna has good performance, within the operation band with a good return loss characteristic performance of less than −10 dB and a moderate gain of 3.5–4.6 dBi. As it can be seen, the 3D printer technology is an efficient method for fast and accurate prototyping of antenna design.
An Q‐factor calibration method for compensation of the I/Q signal imbalances in 5–6 GHz beamforming receiver
Authors: Jung Won‐Jae , Hong Nam‐Pyo , Jang Jong‐Eun , Kim Jin‐Sup , Park Jun‐Seok
Published: August 2018

This article presents 5–6 GHz beamforming receiver with Q‐factor calibrated vector modulator to reduce phase error and amplitude mismatch. Q‐factor of vector modulator IQ network has to be 0.95–1.05 in 5–6 GHz to get under ±3° phase error. Proposed Q‐factor calibration circuit selects the best capacitance and resistance for proper Q‐factor in desired frequency range. Beamforming receiver prototype, which is implemented in 0.13‐μm CMOS, has 0.98–1.03 Q‐factor in 5–6 GHz. The prototype has improved performance than without calibration: its rms phase error is maximum 1.5° (4.5° improved), and amplitude mismatch is maximum 0.47 dB (0.73‐dB improved). In addition, noise figure is 3.8–4.6 dB at 5–6 GHz.
Prediction of RF performances of advanced MOS transistors from DC and low frequency measurements
Authors: Maafri Djabar , Kazemi Esfeh Babak , Saadi Abdelhalim , Yagoub Mustapha C. E. , Raskin Jean‐Pierre
Published: August 2018

This work presents a new method to easily and rapidly extract RF figures of merit of MOSFET transistors. Using DC and low frequency measurements, the extrinsic resistances (Rg, Rs, Rd), the intrinsic conductances (gm, gd), and the input capacitance Cgg have been extracted. The evaluation of these parameters has enabled to compute 2 RF figures of merit (FoM), namely, the current gain cutoff frequency fT and the maximum oscillation frequency fmax. It has been shown that both the proposed method and the conventional RF extraction technique give quite close values.
Study of field distortions introduced by antenna array mobile carrier body
Authors: Ashikhmin A. V. , Pasternak Yu. G. , Rembovsky Yu. A. , Fedorov S. M.
Published: August 2018

In this article was presented a method for optimal location of the “virtual” antenna array elements, based on obtaining a surface map of the same field phase distortion, averaged over the set of frequencies and azimuthal coordinates. This method does not require information about geometry and material properties of the antenna array carrier body, and can significantly improve accuracy of mobile radio direction‐finding systems.
Yagi‐Uda nantenna for 1550 nanometers optical communication systems
Authors: Sethi Waleed Tariq , de Sagazan Olivier , Vettikalladi Hamsakutty , Fathallah Habib , Himdi Mohamed
Published: August 2018

In this letter we propose, for the very first time, a Molybdenum based Yagi‐Uda high‐directional nantenna. It is realized using simple Low Pressure Chemical Vapor Deposition (LPCVD) technique on a silicon substrate for 1550 nm standard optical communication system. The proposed nantenna uses Molybdenum metal as a ground plane while the Yagi‐Uda driven, radiator and directing elements are made up of Aluminum. Grounded Co‐Planar Waveguide (GCPW) technique is used for exciting the nanoantenna in CST Microwave Studio simulator. The nantenna achieves an impedance bandwidth of (193.37–193.71 THz) at a center frequency of 193.5 THz with a high gain and directivity of 12.9 and 16.6 dB, respectively. Near‐field and far‐field performance of the proposed nantenna is also demonstrated via extensive numerical simulations. The results achieved makes the proposed nantenna a viable candidate for applications in the field of nanophotonic circuits and photovoltaic devices working in the optical C‐band window.
Narrowband shielding against electromagnetic interference in LTE 4G systems using complementary frequency selective surfaces
Authors: da Silva B. S. , Campos A. L. P. S. , Gomes Neto A.
Published: August 2018

This article presents the project and fabrication of an electromagnetic shielding using complementary frequency selective surfaces. The proposed structure acts as low pass filter in the bands 1.8–2.3 GHz and 2.86–3.47 GHz, with a narrowband null rejecting undesired frequencies, in this case, 4G band (2.50–2.69 GHz). The project begins by analyzing geometries very well known in the specific literature (cross‐dipole and square‐loop), separately, to determine the dimensions of these geometries efficiently. In addition, computational simulations of a new geometry are made, joining the initial geometries, to observe the behavior of the interaction between them. Therefore, the CFSS is proposed and studied to achieve the desired frequency response. By using the screen printing technique, the EMI shielding is fabricated. Finally, its frequency response is validated experimentally. A good agreement between measurement and simulation is demonstrated in this article, as well as the angular stability of the proposed structure.
Triband planar shared‐aperture antenna array with similar‐shaped radiation patterns
Authors: Li Mingxing , Wu Yongle , Qu Meijun , Jiao Lingxiao , Liu Yuanan
Published: August 2018

In this paper, a triband planar shared‐aperture antenna array is proposed. The proposed antenna array could obtain similar‐shaped radiation patterns at three operating frequency bands. The total structure includes two radiation patch layers, a ground layer and a feeding network layer. Metal vias are used to excite the stacked patches, leading to three resonant frequencies. To verify the proposed antenna array, a 4 × 4 prototype with the overall size of 6.4 × 5.3 × 0.7 cm3 is fabricated and measured. The measured |S11| < −10 dB bandwidths are 13.34–13.82, 17.95‐18.61, and 23.8–25.15 GHz, and measured realized gains are 10.8, 11, and 14.4 dB at 13.5, 18, and 24 GHz.
Low‐cost quad‐band dual antipodal Vivaldi antenna using microstrip to CPS transition
Authors: Bulgaroni Renan , Torres Wesley M. , de Araujo Humberto X. , Casella Ivan R. S. , Capovilla Carlos E.
Published: August 2018

In this article, a new topology of antenna for multi‐band application is proposed, designed, and characterized. This one is based on an array of two antipodal Vivaldi antennas diametrically placed and fed through a microstrip to coplanar strip (CPS) transition, which generates an odd‐order coupling at the input of the elements. The designed antenna was built on a low‐cost substrate (FR‐4), with compatible operation at 1.85–2.00, 2.20–2.85, 3.35–3.81, and 5.00–6.9 GHz (PCS, Bluetooth, WLAN, WiMAX, TD‐SCDMA, and ISM). The measurements, on a fabricated prototype, and the simulations demonstrate the operability and functionality, with satisfactory performance, of the proposed antenna topology.
Abdominal DCE‐MRI reconstruction with deformable motion correction for liver perfusion quantification
Authors: Johansson Adam , Balter James M. , Cao Yue
Published: August 2018

Purpose

Abdominal dynamic contrast‐enhanced (DCE) MRI suffers from motion‐induced artifacts that can blur images and distort contrast‐agent uptake curves. For liver perfusion analysis, image reconstruction with rigid‐body motion correction (RMC) can restore distorted portal‐venous input functions (PVIF) to higher peak amplitudes. However, RMC cannot correct for liver deformation during breathing. We present a reconstruction algorithm with deformable motion correction (DMC) that enables correction of breathing‐induced deformation in the whole abdomen.

Methods

Raw data from a golden‐angle stack‐of‐stars gradient‐echo sequence were collected for 54 DCE‐MRI examinations of 31 patients. For each examination, a respiratory motion signal was extracted from the data and used to reconstruct 21 breathing states from inhale to exhale. The states were aligned with deformable image registration to the end‐exhale state. Resulting deformation fields were used to correct back‐projection images before reconstruction with view sharing. Images with DMC were compared to uncorrected images and images with RMC.

Results

DMC significantly increased the PVIF peak amplitude compared to uncorrected images (P << 0.01, mean increase: 8%) but not compared to RMC. The increased PVIF peak amplitude significantly decreased estimated portal‐venous perfusion in the liver (P << 0.01, mean decrease: 8 ml/(100 ml·min)). DMC also removed artifacts in perfusion maps at the liver edge and reduced blurring of liver tumors for some patients.

Conclusions

DCE‐MRI reconstruction with DMC can restore motion‐distorted uptake curves in the abdomen and remove motion artifacts from reconstructed images and parameter maps but does not significantly improve perfusion quantification in the liver compared to RMC.
Internal radiation dose estimation using multiple D‐shuttle dosimeters for positron emission tomography (PET): A validation study usingNEMAbody phantom
Authors: Islam Md. Shahidul , Watanuki Shoichi , Tashiro Manabu , Watabe Hiroshi
Published: August 2018

Purpose

Internal radiation dosimetry plays an important role in ensuring the safe use of positron emission tomography (PET) technology and is a legal requirement in most countries. We propose a new technique to estimate the internal radiation dose inPETstudies by means of multiple D‐shuttle dosimeters attached on the body surface of the patient.

Methods

Radioactivity in a source organ was estimated iteratively using measurements from multiple D‐shuttle dosimeters with a maximum‐likelihood expectation‐maximization (MLEM) algorithm with dose response from a source to a D‐shuttle dosimeter computed by Monte Carlo simulation. To validate our technique, we performed a phantom study using a National Electrical Manufacturers Association (NEMA) body phantom. The fillable compartments (torso cavity and six spheres) of the phantom were filled with18F‐FDGmixed with pure water using an 800:1 sphere‐to‐background radioactivity concentration ratio. The radioactivity concentrations present in the torso cavity and six spheres were 0.00165MBq/mLand 1.32MBq/mL, respectively. The initial radioactivities of the torso cavity and six spheres (treated as source organs) were 15.9MBq (torso cavity), 34.7MBq (37 mm sphere), 15.1MBq (28 mm sphere), 7.27MBq (22 mm sphere), 3.26MBq (17 mm sphere), 1.54MBq (13 mm sphere), and 0.697MBq (10 mm sphere). Eleven D‐shuttle dosimeters were attached to theNEMAbody phantom surface to obtain information on body surface dose and a mathematicalNEMAbody phantom has been modeled in the Heavy Ion Transport Code System (PHITS) Monte Carlo simulation code.

Results

Radioactivity was estimated in 2 min intervals over a 110‐min total dose time using our proposed technique. A significant correlation (R2= 0.992) was found between actual radioactivity and estimated radioactivity at every 2 min interval for each source organ. The estimated initial radioactivity (mean with standard deviation) was 16.5 ± 0.311MBq (torso cavity), 33.0 ± 0.624MBq (37 mm sphere), 15.7 ± 0.189MBq (28 mm sphere), 7.11 ± 0.738MBq (22 mm sphere), 4.17 ± 0.083MBq (17 mm sphere), 1.48 ± 0.469MBq (13 mm sphere), and 0.865 ± 0.313MBq (10 mm sphere), which were very close to the actual initial radioactivity measurements for each source organ.

Conclusions

The phantom study showed that our technique worked successfully. This technique could be used to estimate internal radiation dosimetry in a clinicalPETstudy.
Comprehensive behavioral analysis of indoleamine 2,3‐dioxygenase knockout mice
Authors: Hirata Nao , Hattori Satoko , Shoji Hirotaka , Funakoshi Hiroshi , Miyakawa Tsuyoshi
Published: August 2018

Aim

Indoleamine 2,3‐dioxygenase 1 (IDO1) metabolizes the essential amino acid tryptophan into kynurenine derivatives, which are involved in neural activity via the kynurenine pathway (KP). IDO1 is an initial rate‐limiting enzyme in the KP and is activated by stress and/or inflammation. The perturbation of IDO1 activity, which causes KP imbalance, is associated with psychiatric and neurological disorders. It has been reported that wild‐type (WT) mice under inflammatory conditions show increased anxiety‐like behavior and decreased novel object recognition, whereas Ido1 knockout (KO) mice do not display these behaviors. However, the behavioral phenotypes of Ido1 KO mice have not yet been fully examined under non‐inflammatory conditions.

Methods

We subjected Ido1 KO mice to a comprehensive behavioral test battery under normal conditions.

Results

Ido1 KO mice and WT mice showed similar locomotor activity, anxiety‐like behavior, social behavior, depression‐like behavior, and fear memory. In the T‐maze test, Ido1 KO mice exhibited weak but nominally significant impairment in the working memory task of the T‐maze, but this result failed to reach study‐wide significance.

Conclusions

Ido1 KO mice did not show any clear behavioral abnormalities under normal conditions. Further studies may be necessary to investigate their behavioral phenotype under inflammatory conditions due to their known roles in inflammation.
A flame retardant rigid polyurethane foam system including functionalized graphene oxide
Authors: Gao Ming , Li Junfei , Zhou Xuan
Published: August 2018

A functionalized graphene oxide (fGO) was prepared by graphene oxide (GO), boric acid and 3‐aminopropyltriethoxysilane in an ethanol aqueous solution using ultrasonic agitation. Its structure was characterized by the Fourier transform infrared (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TG), and elemental analysis. Subsequently, the fGO was incorporated into the flame‐retardant‐polyurethane (FRPU) system, in which fGO as a synergist and reinforcing agent, expandable graphite (EG), and dimethyl methylphosphonate (DMMP) as flame retardants, to improve its the flame‐retardancy and mechanical properties, evidenced by the limiting oxygen index (LOI), vertical burning test (UL‐94) test and the cone calorimeter test (CONE). The LOI value of FRPU/fGO composites reached 28.1% by addition of 0.25 phr fGO and 10 phr EG/DMMP, and its UL‐94 test reached V‐0 rating. The CONE results revealed that fGO could significantly enhance flame retardant properties of FRPU composites, and the peak heat release rate (PHRR) values value of FRPU/fGO remarkably reduced by 32.9%. Moreover, fGO indeed enhanced the mechanical properties of rigid polyurethane foam (RPUF). POLYM. COMPOS., 40:E1274–E1282, 2019. © 2018 Society of Plastics Engineers
Effects of silica nanoparticles on tribology performance of poly(Epoxy Resin‐Bismaleimide)‐based nanocomposites
Authors: Zhang Guoliang , Lu Shichao , Ke Yangchuan
Published: August 2018

Introduction of small nanoparticles into polymer matrix increases the mechanical, tribological, and thermal properties of nanocomposites. In this study, poly(epoxy resin‐bismaleimide‐diaminodiphenylmethane) (EP‐BMI‐DDM) copolymers filled with silica nanoparticles (SNPs) were successfully fabricated through in situ suspension polymerization. To enhance the interfacial adhesion of silica particles to the polymer matrix, the nanoparticles were organo‐modified by silane coupling agent. Results of tensile strength test revealed that increased toughness of the composites was attributed to the microcavitations induced by organo‐modified SNPs (OSNPs). Proper loadings of OSNPs can play a critical role in antifriction performance, with optimal friction coefficient of 0.17 (2 wt% OSNPs content). Thermostabilities of the nanocomposites were characterized by differential thermal gravimetric analysis. At the maximum rate of weight loss of EP‐BMI‐DDM/3 wt% OSNP, the temperature measured 452°C, which is 52°C higher than that of pure EP‐BMI‐DDM copolymers (400°C). The produced nanocomposites feature good thermostability and self‐lubrication can be widely used as wearable material under severe working conditions with higher temperature. POLYM. ENG. SCI., 59:274–283, 2019. © 2018 Society of Plastics Engineers
Novel conjugated patterns of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT complicated polymers onto graphenic nanosheets
Authors: Aghapour Sahar , Agbolaghi Samira , Charoughchi Somaiyeh , Sarvari Raana , Abbasi Farhang
Published: August 2018

The delicacy and connectivity of conductive patterns developed via poly[benzodithiophene‐bis(decyltetradecylthien)naphthothiadiazole] (PBDT‐DTNT) and poly[bis(triisopropylsilylethynyl)benzodithiophene‐bis(decyltetradecylthien)naphthobisthiadiazole] (PBDT‐TIPS‐DTNT‐DT) polymers were investigated on reduced graphene oxide (rGO) nanosheets. The principal driving force for assembly of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT chains onto the rGO nanosheets was π‐stacking. In contrast to poly(3‐hexylthiophene) (P3HT), the surface modification of rGO limited the self‐assembly of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT complicated polymers. The structure of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT chains having fused and infused thiophenic and benzenic rings hindered their molecular ordering compared to P3HT, and therefore the selected area electron diffraction plots demonstrated rings instead of isolated growth planes. Although 2‐thiophene acetic acid (TAA) functional groups and poly(3‐dodecylthiophene) (PDDT) grafted onto rGO nanosheets did not alter the stacking type of the complicated polymers, it made their attachment more difficult. The thickness of π‐stacked patterns ranged from 55 to 70 nm. In the modified areas of rGO, the PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT chains were not capable of being deposited with a π‐interaction. Hence, the surface modification agents prevented the complicated polymers from interconnectedly assembling and, consequently, constructing longer and larger patterns. This hindrance was more noticeable for the supramolecules based on grafted rGO (rGO‐g‐PDDT) and PBDT‐TIPS‐DTNT‐DT. The conductivity of PBDT‐DTNT/rGO superstructures was the highest (14.61–14.89 S cm−1). The patterned nanohybrids could be considered as potential super‐materials for morphology‐templating in the active layers of organic–inorganic photovoltaics. © 2018 Society of Chemical Industry
Unpacking the Social Media Bot: A Typology to Guide Research and Policy
Authors: Gorwa Robert , Guilbeault Douglas
Published: August 2018

Amid widespread reports of digital influence operations during major elections, policymakers, scholars, and journalists have become increasingly interested in the political impact of social media bots. Most recently, platform companies like Facebook and Twitter have been summoned to testify about bots as part of investigations into digitally enabled foreign manipulation during the 2016 U.S. Presidential election. Facing mounting pressure from both the public and from legislators, these companies have been instructed to crack down on apparently malicious bot accounts. But as this article demonstrates, since the earliest writings on bots in the 1990s, there has been substantial confusion as to exactly what a “bot” is and what it does. We argue that multiple forms of ambiguity are responsible for much of the complexity underlying contemporary bot‐related policy, and that before successful policy interventions can be formulated, a more comprehensive understanding of bots—especially how they are defined and measured—will be needed. In this article, we provide a typology of different types of bots, provide clear guidelines for better categorizing political automation, and unpack the impact that it can have on contemporary technology policy. We conclude by outlining the main challenges and ambiguities that will face both researchers and legislators as they tackle bots in the future.
Bile salt hydrolases: Structure and function, substrate preference, and inhibitor development
Authors: Dong Zixing , Lee Byong H.
Published: August 2018

The worldwide trend of limiting the use of antibiotic growth promoters (AGPs) in animal production creates challenges for the animal feed industry, thus necessitating the development of effective non‐antibiotic alternatives to improve animal performance. Increasing evidence has shown that the growth‐promoting effect of AGPs is highly correlated with the reduced activity of bile salt hydrolase (BSH, EC 3.5.1.24), an intestinal bacteria‐producing enzyme that has a negative impact on host fat digestion and energy harvest. Therefore, BSH inhibitors may become novel, attractive alternatives to AGPs. Detailed knowledge of BSH substrate preferences and the wealth of structural data on BSHs provide a solid foundation for rationally tailored BSH inhibitor design. This review focuses on the relationship between structure and function of BSHs based on the crystal structure, kinetic data, molecular docking and comparative structural analyses. The molecular basis for BSH substrate recognition is also discussed. Finally, recent advances and future prospectives in the development of potent, safe, and cost‐effective BSH inhibitors are described.
Using 1HN amide temperature coefficients to define intrinsically disordered regions: An alternative NMR method
Authors: Okazaki Hiroki , Matsuo Naoki , Tenno Takeshi , Goda Natsuko , Shigemitsu Yoshiki , Ota Motonori , Hiroaki Hidekazu
Published: August 2018

This report describes a cost‐effective experimental method for determining an intrinsically disordered protein (IDP) region in a given protein sample. In this area, the most popular (and conventional) means is using the amide (1HN) NMR signal chemical shift distributed in the range of 7.5–8.5 ppm. For this study, we applied an additional step: analysis of 1HN chemical shift temperature coefficients (1HN‐CSTCs) of the signals. We measured 1H–15N two‐dimensional NMR spectra of model IDP samples and ordered samples at four temperatures (288, 293, 298, and 303 K). We derived the 1HN‐CSTC threshold deviation, which gives the best correlation of ordered and disordered regions among the proteins examined (below −3.6 ppb/K). By combining these criteria with the newly optimized chemical shift range (7.8–8.5 ppm), the ratios of both true positive and true negative were improved by approximately 19% (62–81%) compared with the conventional “chemical shift‐only” method.
Refining protein structures using enhanced sampling techniques with restraints derived from an ensemble‐based model
Authors: Ma Tianqi , Zang Tianwu , Wang Qinghua , Ma Jianpeng
Published: August 2018

This paper reports a method for high‐accuracy protein structural refinement, which is a direct extension of the method in our recent publication (Zang, J Chem Phys 2018; 149:072319). It combines a parallel continuous simulated tempering (PCST) method with a temperature‐dependent restraint and a blind model selection scheme. In this work, a single‐reference‐based restraint in previous work was changed to an ensemble‐based model (EBM), in which the non‐bonded Lennard–Jones term for each contacting atomic pair in previous restraining potential was replaced by a multi‐Gaussian function whose parameters are derived from an ensemble of structures such as the ones from various CASP participating groups. The purpose of EBM is to take advantage of partial “correctness” distributed among members of the structural ensemble. Totally 18 targets were refined from the refinement category of CASP10, CASP11 and CASP12. In Top‐1 group, 11 out of 18 targets had better models (greater GDT_TS scores) than the CASPR participants. In Top‐5 group, nine out of 18 were better. Our results show that PCST‐EBM method can considerably improve the low‐accuracy structures.
The first crystal structure of crustacean ferritin that is a hybrid type of H and L ferritin
Authors: Masuda Taro , Zang Jiachen , Zhao Guanghua , Mikami Bunzo
Published: August 2018

Ferritin, a ubiquitous iron storage protein, has a crucial role in innate immunity in arthropods, which have no adaptive immune system. Arthropods are thought to have two types of ferritin molecules: the secreted type and the cytosolic type. Here, we present the first crystal structure of ferritin from crustacean, kuruma prawn (Marsupenaeus japonicus), at 1.16 Å resolution. This shrimp ferritin (MjFer) is the cytosolic type, and its structure shows well‐conserved ferritin fold composed of a 4‐helix bundle that assembles into a cage‐like 24‐mer. The structure of MjFer was more similar to those of human and vertebrate ferritins than to that of the secreted‐type arthropod ferritin from an insect. MjFer possesses both a ferroxidase site and a nucleation site, which are the main characteristics of vertebrate H and L chain ferritins, respectively. The first crystal structure of crustacean ferritin, MjFer, has exceptionally high quality that provides the detailed structural information of metal moving pathway in ferritin.
Prediction of protein flexibility using a conformationally restrained contact map
Authors: Vera Rebecca , Synsmir‐Zizzamia Melissa , Ojinnaka Sarah , Snyder David A.
Published: August 2018

Knowledge of protein flexibility is crucial to understanding protein function. However, probing protein flexibility by either experiment or computational simulations is a difficult process. In particular, many computational approaches to understanding protein flexibility require an experimentally determined protein structure. The Conformationally Restrained Contact Map (CoRe‐CMap) approach reported here couples protein disorder predictions with protein structure predictions and only requires sequence data to predict protein flexibility. This paper reports the application of the CoRe‐CMap model to predicting Lipari‐Szabo order parameters of all proteins for which experimentally derived Lipari‐Szabo order parameters are available in the BioMagResBank: the median root mean square deviation between a protein's predicted and experimentally derived order parameters is 0.124. Additionally, application of the CoRe‐CMap model to predict Lipari‐Szabo order parameters for the 10th Type III Domain in Fibronectin and a homologous domain from Tenascin demonstrates the ability of CoRe‐CMap to predict functionally important differences in protein flexibility.
New global potential energy surface of the MgH2 system and dynamics studies of the reaction H + MgH → Mg + H2
Authors: Zhang Yong , Wang Jiemin , Li Wentao
Published: August 2018

A new global potential energy surface for the ground state of MgH2 was constructed using the permutation invariant polynomial neural network method. About 70 000 ab initio energy points were calculated via the multi‐reference configuration interaction method method with aug‐cc‐pVTZ and aug‐cc‐pVQZ basis sets, and these points were used to construct the potential energy surface (PES). To avoid basis set superposition error, the basis set was extrapolated to the complete basis set limit using the two point energy extrapolation formula. The root mean square error of the present PES is only 8.85 meV. Initial state (v = 0, j = 0) dynamics studies were performed using the time‐dependent wave packet method with a second‐order split operator for the total angular momentum J up to a value of 50. Furthermore, the reaction probability, integral cross section, and thermal rate constant are reported and compared with available theoretical studies.
Challenges in predicting ΔrxnG in solution: Hydronium, hydroxide, and water autoionization
Authors: Dhillon Shamneet , East Allan L. L.
Published: August 2018

Standard non‐semiempirical continuum‐dielectric orbital‐based methods horribly overpredict, by 26‐50 kcal mol−1, the Gibbs energy for the water autoionization reaction 2 H2O(l) → H3O+(aq) + OH–(aq). Here, we demonstrate these errors, fully investigate the reasons for these errors, and show that the use of 4 explicit solvent within the continuum (the “semicontinuum,” “cluster‐continuum,” or “hybrid” technique) can reduce the error of a standard continuum model from 50 to 2 kcal mol−1. Results from pure cluster, pure continuum (several versions including semiempirical ones), and semicontinuum modeling are each presented and discussed. We recommend use of 3 waters around hydronium and 4 waters around hydroxide with standard continua whenever these ions are involved in reaction. To the possible surprise of some, time‐consuming molecular‐dynamics simulations are not needed to reproduce this problematic energy.
Quantum confinement effects on the harmful‐gas‐sensing properties of silicon nanowires
Authors: de Santiago Francisco , Miranda Álvaro , Trejo Alejandro , Salazar Fernando , Carvajal Eliel , Cruz‐Irisson Miguel , Pérez Luis A.
Published: August 2018

In this work, the effects of the adsorption of different toxic gas molecules CO, NO, NO2, and SO2 on the electronic structure of hydrogen‐passivated, [111]‐oriented, silicon nanowires (H‐SiNWs), are studied through density functional theory. To analyze the effects of quantum confinement, three nanowire diameters are considered. The results show that the adsorption energies are almost independent of the nanowire diameter with NO2 being the most strongly adsorbed molecule (∼3.44 eV). The electronic structure of small‐diameter H‐SiNWs is modified due to the creation of isolated defect‐like states on molecule adsorption. However, these discrete levels are eventually hybridized with the former nanowire states as the nanowire diameter increases and quantum confinement effects become less evident. Hence, there is a range of small nanowire diameters with distinctive band gaps and adsorption energies for each molecule species.
An Interferometric Synthetic Aperture Radar (InSAR) Habitat Suitability Model to Identify Overwinter Conditions for Coregonine Whitefishes in Arctic Lagoons
Authors: Tibbles Marguerite , Falke Jeffrey A. , Mahoney Andrew R. , Robards Martin D. , Seitz Andrew C.
Published: August 2018

Lagoons provide critical habitats for many fishes, including coregonine whitefishes, which are a mainstay in many subsistence fisheries of rural communities in Arctic Alaska. Despite their importance, little is known about the overwintering habits of whitefishes in Arctic Alaska due to the challenges associated with sampling during winter. We developed a habitat suitability (HS) model to understand the potential range of physical conditions that whitefishes experience during the Arctic winter, using three indicator lagoons that represent a range of environmental characteristics. The HS model was built using a three‐step approach. First, remote sensing that uses interferometric synthetic aperture radar (InSAR) identified areas of floating and bottomfast ice. Second, through in‐field ground‐truthing, we confirmed the presence and quality of liquid water (water depth, temperature, and dissolved oxygen) beneath the ice cover. Third, we assessed the suitability of that liquid water as habitat for whitefishes based on published literature and expert interpretation of water quality parameters. InSAR determined that 0, 65.4, and 88.2% of the three lagoons were composed of floating ice corresponding with areas of liquid water beneath a layer of ice. The HS model indicated that all three lagoons had reduced suitability as whitefish habitat in winter than in summer due to the loss of habitat because of the presence of bottomfast ice and a reduction in the quality of liquid water due to cold temperatures, high salinities, and low dissolved oxygen levels. However, only the shallowest lagoon had lethal conditions and zero suitability as whitefish habitat. The methods outlined here provide a simple, cost‐effective method to identify habitats that consistently provide critical winter habitat and integrate remote sensing in a HS model framework.
Coho Salmon Colonization of Oregon's Upper Willamette River Basin
Authors: Keefer Matthew L. , Blubaugh Timothy J. , Clabough Tami S. , Jepson Michael A. , Naughton George P. , Caudill Christopher C.
Published: August 2018

Coho Salmon Oncorhynchus kisutch were historically absent from a major Columbia River subbasin, the upper Willamette River (UWR), until a fishway was installed at Willamette Falls and a sustained stocking program was implemented in the 1950s. Despite decades of stocking from three diverse source populations (early run, late run, and coastal Coho Salmon) during the second half of the twentieth century, adult abundance above the falls was less than 1,000 annually during the 1990s. A recent surge (>25,000 adults in 2009) has raised concerns about potential interactions with two native anadromous salmonids listed under the U.S. Endangered Species Act: UWR winter‐run steelhead O. mykiss and UWR spring‐run Chinook Salmon O. tshawytscha. We analyzed Coho Salmon stocking records and estimates of abundance from 1954–2017 to summarize population history, demographics, and adult phenology. We also characterized current Coho Salmon distribution using radiotelemetry (n = 219 adults in 2014) and evaluated potential mechanisms associated with changes in adult abundance. We identified a shift in adult migration timing over the time series that was consistent with an increase in late‐run traits and environmental changes affecting migration cues. The distribution of radio‐tagged adults among UWR subbasins was only weakly correlated with past stocking efforts, suggesting that habitat conditions, stocked phenotype, adaptation and range expansion by descendants of the relict stocked populations, or colonization from regional source populations strongly influenced current subpopulation abundance. Annual counts of returning UWR Coho Salmon were positively correlated with counts of Columbia River Coho salmon, suggesting a shared response to freshwater habitat or ocean conditions. Regardless of the underlying mechanisms affecting UWR Coho Salmon distribution and population size, the results illustrate the complex dynamics between changing landscapes and migration corridors, the introduction of nonnative species for harvest management goals, and the potential for nonnative fish to affect the conservation of native populations.
Sites of Synergy: Strategies for Readers Navigating Nonfiction Picture Books
Authors: Shimek Courtney
Published: August 2018

The category of nonfiction picture books has changed in the past few decades, putting more emphasis on engaging writing styles, attention to accuracy, and using synergic relations between images and texts. As a result of this shift, the strategies taught to students for reading nonfiction picture books must change. The author presents five strategies that readers navigating new nonfiction picture books can use to comprehend all of the information provided by authors and illustrators: reading the pictures, tracking the words, focusing on the medium, analyzing the back matter, and highlighting the text in visual elements. When readers use these strategies, new nonfiction picture books encourage them to think critically, engage in their own research, and dive deeply into the content they are reading about.
Kähler uniformization from holographic renormalization group flows of M5-branes
Authors: Fluder Martin
Published: August 2018

Abstract

In this paper, we initiate the study of holographic renormalization group flows for the metric of four-manifolds. In particular, we derive a set of equations which govern the evolution of a generic Kähler four-manifold along the renormalization group flow in seven-dimensional gauged supergravity. The physical eleven-dimensional M-theory setup is given by a stack of M5-branes wrapping a calibrated Kähler four-cycle inside a Calabi-Yau threefold. By topologically twisting the theory in the ultraviolet, we may choose an arbitrary Kähler metric on the four-cycle as an asymptotic boundary condition. We find that at the infrared fixed point, we reach a Kähler-Einstein metric, which can be interpreted as an indication of “uniformizing” behavior of the flow.
A flavoured dark sector
Authors: Renner Sophie , Schwaller Pedro
Published: August 2018

Abstract

We explore the phenomenology of a QCD-like dark sector which confines around the GeV scale. The dark sector inherits a flavour structure from a coupling between dark quarks and SM quarks via a heavy mediator, which leads to exciting new phenomena. While stable baryonic bound states are the dark matter candidates, the phenomenology is dominated by the lightest composite mesons, the dark pions, which can have decay lengths ranging from millimetres to hundreds of meters. For masses below 1.5 GeV, their exclusive decays to SM mesons are calculated for the first time by matching both dark and visible sectors to a chiral Lagrangian. Constraints from big bang nucleosynthesis, dark matter direct detection and flavour single out a small region of allowed parameter space for dark pion masses below 5 GeV. It is best probed by the fixed target experiments NA62 and SHiP, where dark pions can be produced copiously in rare decays like B → Kπ

D
. The dominant π
D
→ K
±
π
∓ and π

D
→ 3π decay modes are a smoking gun for a CP-odd, flavour violating new resonance. Heavier dark pions are best searched for at the LHC, where they decay after hadronisation to produce jets which emerge into SM states within the detector. Here the flavour structure ensures different flavours emerge on different length scales, leading to a striking new feature in the emerging jets signature.
Implication of gut microbiota metabolites in cardiovascular and metabolic diseases
Authors: Brial Francois , Le Lay Aurélie , Dumas Marc-Emmanuel , Gauguier Dominique
Published: August 2018

Evidence from the literature keeps highlighting the impact of mutualistic bacterial communities of the gut microbiota on human health. The gut microbita is a complex ecosystem of symbiotic bacteria which contributes to mammalian host biology by processing, otherwise, indigestible nutrients, supplying essential metabolites, and contributing to modulate its immune system. Advances in sequencing technologies have enabled structural analysis of the human gut microbiota and allowed detection of changes in gut bacterial composition in several common diseases, including cardiometabolic disorders. Biological signals sent by the gut microbiota to the host, including microbial metabolites and pro-inflammatory molecules, mediate microbiome–host genome cross-talk. This rapidly expanding line of research can identify disease-causing and disease-predictive microbial metabolite biomarkers, which can be translated into novel biodiagnostic tests, dietary supplements, and nutritional interventions for personalized therapeutic developments in common diseases. Here, we review results from the most significant studies dealing with the association of products from the gut microbial metabolism with cardiometabolic disorders. We underline the importance of these postbiotic biomarkers in the diagnosis and treatment of human disorders.