bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Encoding of Photocaged Tyrosines with Improved Light‐Activation Properties for the Optical Control of Protease Function
Authors: Luo Ji , Torres‐Kolbus Jessica , Liu Jihe , Deiters Alexander 
Published: June 2017

AbstractWe genetically encoded three new caged tyrosine analogues with improved photochemical properties by using an engineered pyrrolysyl‐tRNA synthetase/tRNACUA pair in bacterial and mammalian cells. We applied the new tyrosine analogues to the photoregulation of firefly luciferase by caging its key tyrosine residue, Tyr340, and observed excellent off‐to‐on light switching. This reporter was then used to evaluate the activation rates of the different light‐removable protecting groups in live cells. We identified the nitropiperonyl caging group as an excellent compromise between incorporation efficiency and photoactivation properties. To demonstrate applicability of the new caged tyrosines, an important proteolytic enzyme, tobacco etch virus (TEV) protease, was engineered for optical control. The ability to incorporate differently caged tyrosine analogues into proteins in live cells further expands the unnatural amino acid and optogenetic toolbox.
Layer Stacked Iodine and Phosphorus Co‐doped C3N4 for Enhanced Visible‐Light Photocatalytic Hydrogen Evolution
Authors: Huang Yuqing , Yan Qing , Yan Haijing , Tang Yunqi , Chen Shuai , Yu Zheying , Tian Chungui , Jiang Baojiang 
Published: June 2017

AbstractHetero‐element doping is one of the most effective methods for band gap regulation of semiconductor photocatalysts. Here, a novel layer stacking of iodine and phosphorus co‐doped carbon nitride (I/P‐CN) was prepared from a novel supramolecular precursor. The obtained I/P‐CN exhibits significantly enhanced visible‐light photocatalytic hydrogen production (93.9 μmol h−1) compared with bulk carbon nitride. Moreover, it reveals a consistent cycle stability for photocatalytic application. The marked improvement in photocatalytic activity is the result of iodine and phosphorus co‐doping bringing about a decrease in the band gap and an increase of absorption intensity and width. The unique layer in the stacking structure facilitates an increase in specific surface area and active reaction sites. Our research opens up a new strategy to synthesize multiple elements co‐doped carbon nitride as a promising metal‐free photocatalyst for hydrogen evolution under visible light.
Achieving High Levels of NMR‐Hyperpolarization in Aqueous Media With Minimal Catalyst Contamination Using SABRE
Authors: Iali Wissam , Olaru Alexandra M. , Green Gary G. R. , Duckett Simon B. 
Published: June 2017

AbstractSignal amplification by reversible exchange (SABRE) is shown to allow access to strongly enhanced 1H NMR signals in a range of substrates in aqueous media. To achieve this outcome, phase‐transfer catalysis is exploited, which leads to less than 1.5×10−6 mol dm−3 of the iridium catalyst in the aqueous phase. These observations reflect a compelling route to produce a saline‐based hyperpolarized bolus in just a few seconds for subsequent in vivo MRI monitoring. The new process has been called catalyst separated hyperpolarization through signal amplification by reversible exchange or CASH‐SABRE. We illustrate this method for the substrates pyrazine, 5‐methylpyrimidine, 4,6‐d2‐methyl nicotinate, 4,6‐d2‐nicotinamide and pyridazine achieving 1H signal gains of approximately 790‐, 340‐, 3000‐, 260‐ and 380‐fold per proton at 9.4 T at the time point at which phase separation is complete.
Enantioselective cytotoxicity of ZnS:Mn quantum dots in A549 cells
Authors: Kuznetsova V.A. , Visheratina A.K. , Ryan A. , Martynenko I.V. , Loudon A. , Maguire C.M. , Purcell‐Milton F. , Orlova A.O. , Baranov A.V. , Fedorov A.V. , Prina‐Mello A. , Volkov Y. , Gun'Ko Y.K. 
Published: June 2017

AbstractChirality strongly influences many biological properties of materials, such as cell accumulation, enzymatic activity, and toxicity. In the past decade, it has been shown that quantum dots (QDs), fluorescent semiconductor nanoparticles with unique optical properties, can demonstrate optical activity due to chiral ligands bound on their surface. Optically active QDs could find potential applications in biomedical research, therapy, and diagnostics. Consequently, it is very important to investigate the interaction of QDs capped with chiral ligands with living cells. The aim of our study was to investigate the influence of the induced chirality of Mn‐doped ZnS QDs on the viability of A549 cells. These QDs were stabilized with D‐ and L‐cysteine using a ligand exchange technique. The optical properties of QDs were studied using UV–Vis, photoluminescence (PL), and circular dichroism (CD) spectroscopy. The cytotoxicity of QDs was investigated by high content screening analysis. It was found that QDs stabilized by opposite ligand enantiomers, had identical PL and UV–Vis spectra and mirror‐imaged CD spectra, but displayed different cytotoxicity: QDs capped with D‐cysteine had greater cytotoxicity than L‐cysteine capped QDs.
Chiral separation and modeling of baclofen, bupropion, and etodolac profens on amylose reversed phase chiral column
Authors: Ali Imran , Suhail Mohd. , Alothman Zeid A. , Alwarthan Abdulrahman 
Published: June 2017

AbstractChiral resolution of baclofen, bupropion, and etodolac profens was obtained with amylose derivatized chiral reversed stationary phase (carbamate groups). The eluent used for bupropion and etodolac was MeOH–water (20:80, v/v) and for baclofen was water–methanol (95:5, v/v). The eluent run rates, finding wavelength and temperature, were 1.0 mL/min, 220 nm and 27 ± 1 °C for all the eluents. The magnitude of the retardation factors for S‐ and R‐enantiomers of baclofen, bupropion, and etodolac were 1.37, 2.62, 2.25, 3.25, 1.8, and 3.0. The magnitudes of separation and resolution factors were 1.90, 1.44, and 1.67 and 2.77, 2.35, and 2.04. Limits of detection and quantitation were 1.0–2.0 and 5.1–10.0 μg/mL. Chiral recognition mechanisms were recognized by simulation and high‐performance liquid chromatography (HPLC) experiments. It was seen that hydrogen interactions, hydrophobic interactions, and π–π exchanges were the chief interactions for chiral recognition mechanisms. The described methods may be exploited for the chiral separation of baclofen, bupropion, and etodolac profens in any unknown sample.
LINEAR REGRESSION ANALYSIS OF THE INFLUENCE OF WESTERN NORTH PACIFIC TROPICAL CYCLONES ON THEIR LARGE‐SCALE ENVIRONMENT
Authors: Xing‐Zhi SUN , Zhong ZHONG , Jing JIANG 
Published: June 2017

AbstractInfluences of the western North Pacific (WNP) tropical cyclones (TCs) on their large‐scale environment are investigated by lag regressing several physical variables, including 850 hPa relative vorticity, surface zonal wind, total column water vapor, outgoing longwave radiation (OLR), precipitation and sea surface temperature (SST), on an index of TC activity accumulated cyclone energy (ACE) on a monthly time scale. Differences between these variables on the monthly and weekly time scales are discussed. The results show that: (1) The zonal wind regressed against ACE on the monthly time scale is more significant than that on the weekly time scale for both its intensity and scope. The high‐intensity and long‐lifetime TCs near the equatorial region have a positive effect on triggering or strengthening surface westerly anomalies in the equatorial region. The long‐lived and intense equatorial surface westerly anomalies can cause westerly wind bursts, which is believed to be a major factor during the occurrence and development of ENSO events. (2) More variables such as OLR, precipitation and SST exhibit a feature corresponding to El Niño on a monthly time scale compared to that on a weekly time scale, which suggests that TC activities on a monthly time scale are more closely associated with the ENSO cycle. (3) One to two months after the genesis of TCs, the column water vapor decreases while OLR increases at the TC genesis region. This could reduce the potential for TC genesis. Although the SST decrease caused by TCs only occurs at a small spatial scale, it can be spread to a large scale via oceanic and atmospheric propagation exhibiting feedback effect. In addition, the feedback does not occur instantaneously but with a certain lag, which explains why the signal of TC influences on large‐scale environment is more pronounced on the monthly time scale.
AN EXPERIMENTAL STUDY ON RESISTIVITY AND CONDUCTIVE MECHANISM IN LOW‐PERMEABILITY RESERVOIRS WITH COMPLEX WETTABILITY
Authors: Cheng FENG , Zhi‐Qiang MAO , Wen YIN , Yu‐Jiang SHI , Bin ZHANG , Xiao‐Hui WANG , Gao‐Ren LI 
Published: June 2017

AbstractAs the clay film developed in low‐permeability lithologic reservoirs absorbs oil, reservoirs become oil‐wet, which results in abnormally high resistivity oil‐water layers and water layers. Such layers bring great challenges to the identification of oil and water layers. In order to make clear the resistivity response characteristics and conductive mechanism in reservoirs with different wettability, cores were selected in Chang 8 formation, Yanchang group, Upper Triassic, the western Ordos basin of China. Experiments were conducted with these samples to simulate the process of oil displacing water, ageing and water displacing oil. In addition, the contact angles of thin slices after washing oil were also tested. The experimental results show that abnormally high resistivity cores are not completely water‐wet after washing oil. However, the formation factors of abnormally high resistivity cores and normal resistivity cores have little difference. In the process of oil displacing water, the relationship between normal resistivity core resistivity index and water saturation is linear in a log‐log plot, while that of abnormally high resistivity cores is convex. The resistivity of abnormally high resistivity cores remains unchanged during ageing process. Combining the analysis of nuclear magnetic resonance (NMR) T2 spectra under different conditions, it can be inferred that wettability of abnormally high resistivity cores has become less water‐wet after oil displacing water, whereas the ageing process has little effect on the wettability. In the process of water displacing oil, the relation between abnormally high resistivity core resistivity index and water saturation is almost linear, which shows that the conductive structure of rock is not changed. Based on the analyses and discussions of these experimental results, a hydrocarbon accumulation mode and the corresponding conductive mechanism are proposed for low‐permeability reservoirs with complex wettability. It shows that abnormally high resistivity water layers are caused by the destruction of continuous conductive paths under oil‐wet condition. The researches and experiments are of great importance for understanding the conductive mechanism, identifying oil and water layers and evaluating water flooded formations in low‐permeability reservoirs with complex wettability.
SIMULATION OF CFC‐11 DISTRIBUTION BASED ON THE GLOBAL OCEANIC CARBON CYCLE MODEL MOM4 L40 AND AN ASSESSMENT OF ITS VENTILATION CAPABILITY
Authors: Juan TAN , Qing‐Quan LI , Lan‐Ning WANG , Qi‐Geng ZHAO 
Published: June 2017

AbstractCFC‐11 is an important tool used to assess oceanic cycle models. The CFC‐11 which is dissolved in seawater can be used to analyze the ventilation of the oceans. In this study, a tracer CFC‐11 module was developed based on the global oceanic carbon cycle circulation model MOM4 L40, which was developed by the National Climate Center of China Meteorological Administration. Then, the model was employed to study the distribution of CFC‐11 in the global oceans, and also to assess the model's ventilation capacity. The simulated parameters, such as the global sea surfaces' CFC‐11 concentrations, inventory, vertical penetration depths, and concentration distributions, were verified against the actual observations. The results showed that the model reasonably simulated the surface and vertical distribution of the CFC‐11. The main storage areas of the CFC‐11 were determined to be located in the Northwest Atlantic Ocean, subtropical North Pacific Ocean, and the Southern Ocean. The distributions of the CFC‐11 concentrations on the oceanic surfaces were found to be remarkably affected by the sea surfaces' temperatures. The distribution of the simulated CFC‐11 was found to have a high agreement with that of the actual observations, and showed an opposite gradient to the sea surfaces' temperatures. When compared with the observations of five sections located in three oceans, the simulated results of the CFC‐11 were in general agreement with the observations in the majority of the areas. In addition, the distribution of the simulated CFC‐11 was found to be in agreement with meridional overturning circulation in the global oceans, and an improved simulation of the Southern Ocean and deep oceans, as well as the penetration depths, were achieved. However, there were some deviations observed between the observations and simulations. For example, in the North Atlantic Ocean, where a main storage of the CFC‐11 was located, the model underestimated the absorption of the CFC‐11, which was found to be related to the over‐transport simulations from the high latitudes to the low latitudes. These results may have been influenced by the thermohaline circulation and forced data. Overall, it was determined that the MOM L40 reasonably simulated the absorption of the total CFC‐11 in the oceans, and effectively reproduced the oceans' ventilation capabilities by simulating the passive tracer CFC‐11.
Association between patients' perception of the comorbidity burden and symptoms in outpatients with common solid tumors
Authors: Ritchie Christine S. , Zhao Fengmin , Patel Kanan , Manola Judith , Kvale Elizabeth A. , Snyder Claire F. , Fisch Michael J. 
Published: June 2017

BACKGROUNDCancer patients' symptom burden is commonly attributed to their cancer and treatment. Increasingly, cancer patients have many other chronic comorbid conditions. However, the degree to which these comorbid conditions may contribute to the patient‐reported symptom burden is unclear.METHODSThis study explored the relations between the presence of comorbid conditions, the symptom experience and burden, and the perceived bother from cancer or comorbid conditions in 3106 cancer patients. The associations between the number of comorbidities (identified from current medications), the patient‐reported symptom burden (the number of symptoms scored as ≥7 on the 13‐item MD Anderson Symptom Inventory physical scale), the patient‐reported bother from comorbid conditions and from cancer (from “not at all” to “extremely”), and the clinician‐reported difficulty in caring for patients' symptoms were examined.RESULTSAccording to medication lists, 19% of the patients had at least 5 of 12 comorbid conditions. Approximately 39% rated at least 1 symptom as ≥ 7, and this proportion increased with an increasing number of comorbid conditions (48% with ≥ 5 comorbid conditions vs 36% with 1 comorbid condition). One‐third of the patients reported moderate or worse bother, and this was significantly associated with an increased number of comorbid conditions (odds ratio [OR], 2.4) and an increased symptom burden (OR, 1.22). Clinician ratings of difficulty in managing patients' symptoms were significantly associated with bother from cancer (OR, 2.0), comorbid conditions (OR, 1.6), and symptom burden (OR, 1.1).CONCLUSIONSComorbidity is common in cancer patients and is associated with a greater symptom burden and clinician reports of difficulty in managing patients' symptoms. Greater attention to comorbid conditions is needed to optimize the symptom management of cancer patients with multimorbidity. Cancer 2017;123:3835–3842. © 2017 American Cancer Society
The critical role of EBUS‐TBNA cytology in the staging of mediastinal lymph nodes in lung cancer patients: A correlation study with positron emission tomography findings
Authors: Lilo Mohammed T. , Allison Derek B. , Younes Bouchra K. , Cui Min , Askin Fred B. , Gabrielson Edward , Li Qing Kay 
Published: June 2017

BACKGROUNDThe sensitivity and specificity of positron emission tomography (PET) have been significantly improved for the identification of malignancies in recent years; however, it is still necessary to confirm PET findings in a lymph node (LN) by direct tissue sampling. Endobronchial ultrasound–guided transbronchial needle aspiration (EBUS‐TBNA) is the most commonly used approach for diagnosing and staging mediastinal LNs, particularly in lung cancer patients with locally advanced disease. Despite this fact, evidence‐based studies of EBUS‐TBNA cytology and PET findings are still suboptimal.METHODSThe electronic database at the Johns Hopkins Medical Institutions and the pathology archives were searched to identify patients with mediastinal lymphadenopathy who had both EBUS‐TBNA mediastinal LN sampling and a PET scan over a 14‐month period. Patients suspected of having lung cancer and patients with a history of lung cancer were included in this study. Cytological diagnoses and follow‐up surgical LN diagnoses were reviewed and correlated with PET scan findings.RESULTSA total of 140 LNs from 79 patients, including 86 PET‐positive LNs and 54 PET‐negative LNs, were included. The most frequently sampled LNs were 4R and 7. The average size of PET‐positive and PET‐negative LNs was 1.2 and 1.6 cm, respectively. Among PET‐positive LNs, 41.9% were malignant, 41.9% showed reactive changes or granulomatous inflammation, and 9.3% were nondiagnostic by EBUS‐TBNA. However, among PET‐negative LNs, 74.1% showed reactive changes or granulomatous inflammation, 7.4% were malignant, and 18.5% were nondiagnostic by EBUS‐TBNA.CONCLUSIONSThe data demonstrate that EBUS‐TBNA cytology improves the diagnostic accuracy of mediastinal LNs and clinical staging. Furthermore, EBUS‐TBNA may identify additional malignant LNs (7.4%), and this highlights the risk for false‐negative findings with PET scanning in isolation. Cancer Cytopathol 2017;125:717‐25. © 2017 American Cancer Society.
Three‐dimensional visualization of ocellar interneurons of the orchid bee Euglossa imperialis using micro X‐ray computed tomography
Authors: Ribi Willi , Zeil Jochen 
Published: June 2017

AbstractWe used contrast‐optimized micro X‐ray computed tomography (mCT) to trace the profiles of the full complement of large ocellar L‐neurons in the male orchid bee Euglossa imperialis. We find that most L‐neurons collect information from either the dorsal or the ventral retinae in both median and lateral ocelli, with only three neurons associated with the median ocellus having dendritic branches in both dorsal and ventral retina. In the median ocellus, we find also L‐neurons that either collect information from the left or the right half of the ocellar plexus and two neurons that have a split dendritic tree in both halves. Fourteen large L‐neurons collect information from the median ocellus and six to seven L‐neurons from each of the lateral ocelli. The only L‐neurons that project to the contralateral protocerebrum are those that have their dendritic branches in the ventral plexi of both median and lateral ocelli. The target areas of dorsal L‐neurons from the lateral ocelli include a tract of mechanosensory fibers originating in the antennae. We compare our findings with what is known from the ocellar systems of other insects, make a number of functional inferences and discuss the advantages and disadvantages of mCT scans for the purpose of tracing large neuron profiles.
In Situ Growth of Covalent Organic Framework Shells on Silica Microspheres for Application in Liquid Chromatography
Authors: Wang Lu‐Liang , Yang Cheng‐Xiong , Yan Xiu‐Ping 
Published: June 2017

AbstractA facile, in situ growth strategy for the synthesis of monodispersed COF@SiO2 microspheres is reported. The microspheres have uniform and controllable COF shells, and are used as the stationary phase for HPLC. The TpBD COF, constructed from 1,3,5‐triformylphloroglucinol (Tp) and benzidine (BD), is taken as the COF shell, and aminosilica (SiO2−NH2) is employed as the core to support the TpBD shell. The TpBD shell thickness is adjusted by controlling the concentrations of the Tp and BD monomers. The TpBD@SiO2 packed columns show excellent hydrophobic selectivity, and good reproducibility for the separation of neutral (toluene and ethylbenzene, polycyclic aromatic hydrocarbons), acidic (hydroquinone, p‐cresol, and p‐chlorophenol), and basic molecules (nucleobases, nucleosides, and deoxynucleosides).
Activation of Ternary Transition Metal Chalcogenide Basal Planes through Chemical Strain for the Hydrogen Evolution Reaction
Authors: Kim Yongshin , Tiwari Anand P. , Prakash Om , Lee Hyoyoung 
Published: June 2017

AbstractInvited for this month's cover are collaborators from the Institute for Basic Science (South Korea), Sungkyunkwan University (South Korea), and Banaras Hindu University (India). The cover picture shows the two‐dimensional layered transition metal chalcogenide for efficient hydrogen evolution. Read the full text of the article at 10.1002/cplu.201700164.
Flicking the Switch on Donor–Acceptor Interactions in Hexaazatrinaphthalene Dyes: A Spectroscopic and Computational Study
Authors: Barnsley Jonathan E. , Lomax Bethany A. , McLay James R. W. , Larsen Christopher B. , Lucas Nigel T. , Gordon Keith C. 
Published: June 2017

AbstractA series of donor–acceptor compounds based on triphenylamine and hexaazatrinaphthalene are investigated. Using a variety of linker units, it is possible to tune the intensity of the low‐energy transition from 8 000 m−1 cm−1 to 24 000 m−1 cm−1 and vary the wavelength between λ=430 to 490 nm. The effect of the linker may be observed in the resonance Raman spectra with linker unit modes showing strong enhancement when they are coupled to the charge‐transfer transition. This is evident in the case of the C≡C and triazolyl linker units. Charge transfer is consistent with DFT calculations, which implicate some linkers as having pseudo‐donor‐like behaviour. The emission spectra of the dyes are solvatochromic with Stokes shift versus solvent parameter gradients of 20 000 cm−1, showing that the dipole change is still large even when the bridge becomes involved in the transition.
Analysis and design of highly linear triode‐mode based OTA and its application to a wide tunable Gm‐C filter
Authors: Rezaei Farzan , Carvajal Ramón G. 
Published: June 2017

SummaryIn this paper, a new highly linear operational transconductance amplifier (OTA) based on triode‐mode input transistors is introduced. An analysis based on theoretical relations and simulation results is presented that aims to obtain the best operating points of triode‐mode and cascode transistors to achieve the highest linearity. The proposed analysis is utilized to design a linear pseudo‐differential OTA, benefiting a linear common mode feedforward and an appropriate common mode feedback circuit. The common mode feedforward circuit is also regulated in the same manner as main the transconductor to stabilize the output common mode voltage during tuning action and achieve higher common mode rejection ratio. Proposed OTA is used to implement a tunable low‐power linear Gm‐C filter. The cutoff frequency of the filter is tunable from 2.7 to 44 MHz while its power consumption changes from 3.5 to 8.5 mW in the entire tuning range. By applying input voltages up to 1.1 Vp‐p, the filter's IM3 remains less than −48 dB for various cutoff frequencies. The proposed OTA and filter are simulated in 0.18‐μm CMOS technology with Hspice simulator. Copyright © 2017 John Wiley & Sons, Ltd.