bluuebunny/crossref_metadata_2025 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

We 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

Hetero‐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

Signal 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

Chirality 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

Chiral 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

Influences 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

As 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

CFC‐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

BACKGROUND

Cancer 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.

METHODS

This 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.

RESULTS

According 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).

CONCLUSIONS

Comorbidity 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
Triage of the indeterminate thyroid aspirate: What are the options for the practicing cytopathologist?
Authors: Onenerk Ayse M. , Pusztaszeri Marc P. , Canberk Sule , Faquin William C.
Published: June 2017

Fine‐needle aspiration (FNA) plays a key role in the early evaluation of patients with thyroid nodules; however, from 15% to 30% of FNA specimens are cytologically indeterminate. Molecular testing has proven useful when applied to indeterminate thyroid FNAs, and its use has been endorsed in the American Thyroid Association guidelines. In addition to the noncommercial (“in‐house”) application of v‐Raf murine sarcoma viral oncogene homolog B1 (BRAF), rat sarcoma (RAS), rearranged in transformation/papillary thyroid carcinoma (RET/PTC), and peroxisome proliferator‐activated receptor γ/paired box gene 8 (PPARγ/PAX8) testing, there are currently 3 commercially available molecular panels that vary in their relative reported performances, strengths, and limitations. Here, we discuss the role of molecular testing for indeterminate thyroid aspirates, taking into consideration the recent reclassification of the encapsulated follicular variant of papillary thyroid carcinoma (PTC) as “noninvasive follicular neoplasm with papillary‐like nuclear features (NIFTP).” Cancer Cytopathol 2017;125(6 suppl):477‐85. © 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

BACKGROUND

The 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.

METHODS

The 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.

RESULTS

A 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.

CONCLUSIONS

The 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

We 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

A 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

Invited 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.
Biomarkers of Renal Function: Towards Clinical Actionability
Authors: Binnenmars S Heleen , Hijmans RS , Navis G , de Borst MH
Published: June 2017

This review provides an overview of the clinical value of the most relevant renal biomarkers, focusing on two main clinical conditions: acute kidney injury and chronic kidney disease. We categorize biomarkers according to their actionability, in terms of a documented response to treatment in relation to outcomes. Furthermore, we introduce a new category of renal biomarkers, metabolic biomarkers, and underscore their capacity to be highly actionable.
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

A 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

In 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.
A novel low‐loss control strategy for bidirectional DC–DC converter
Authors: Dung Nguyen Anh , Hieu Pham Phu , Hsieh Yao‐Ching , Lin Jing‐Yuan , Liu Yu‐Chen , Chiu Huang‐Jen
Published: June 2017

Bidirectional DC–DC converter with phase‐shift control is commonly used for hybrid electric vehicle and fuel‐cell vehicle applications. This converter is characterized by simple circuit topology and soft‐switching implementation without additional devices. Despite these advantages, the efficiency is poor at light load condition because of high switching and conduction losses caused by high RMS inductor current. To achieve zero‐voltage switching (ZVS) for all power MOSFETs, a constant offset inductor current is maintained to conduct the antiparallel body diodes before MOSFETs turn on. A control strategy of combining duty ratio and phase‐shift modulation is proposed to reach the constant offset current. By reaching the constant offset current, the RMS inductor current can be reduced significantly, and ZVS can be achieved in all load variation ranges, resulting in high efficiency. A 2.5‐kW prototype is implemented to verify the control scheme, and a minimum efficiency of 97.3% is achieved at light load condition. Copyright © 2017 John Wiley & Sons, Ltd.
Toxicity and Protective Effect of Phenolic‐Enriched Ethylacetate Fraction of Ocimum gratissimum (Linn.) Leaf against Acute Inflammation and Oxidative Stress in Rats
Authors: Ajayi Abayomi M. , Umukoro Solomon , Ben‐Azu Benneth , Adzu Bulus , Ademowo Olusegun G.
Published: June 2017

Preclinical Research

Ocimum gratissimum L. leaves have attracted considerable attention from researchers because of their medicinal value that include anti‐inflammatory, analgesic, antimicrobial, and antioxidant activities. In the present study, the toxicity and the protective effect of phenolic extract of O. gratissimum leaf (EAFOg) against acute inflammation and oxidative stress in rats was assessed. EAFOg, enriched in phenols had no cytotoxic effect against CHO‐k1 cells, and no lethality against brine shrimp eggs or mice at a dose of 2000 mg/kg. EAFOg (50 and 100 mg/kg) reduced paw edema by 47% and 61%, compared to 29% with the COX‐2 inhibitor, SC58125 (1 mg/kg) and 81% with indomethacin (5 mg/kg), respectively. In the rat carrageenan‐induced air pouch model, EAFOg reduced exudate volume, leucocyte count, nitrite, TNF‐α, and myeloperoxidase activity. EAFOg also protected against carrageenan‐induced lipid peroxidation and glutathione depletion. These results provide evidence of the protective effects of EAFOg against acute inflammation and oxidative stress in rats. Drug Dev Res 78 : 135‐145, 2017. © 2017 Wiley Periodicals, Inc.
Comparative evaluation of probiotics effects on plasma glucose, lipid, and insulin levels in streptozotocin‐induced diabetic rats
Authors: Memarrast Faeghe , Ghafouri‐Fard Soudeh , Kolivand Sedighe , Jafary‐Nodooshan Saeedeh , Neyazi Nadia , Sadroddiny Esmaeil , Motevaseli Elahe
Published: June 2017

Background

Diabetes is a chronic disorder caused by the relative decrease in insulin production from the pancreas, tissue resistance to insulin, or both. Daily consumption of probiotics, particularly Lactobacilli, has been proposed as a new strategy for prevention or control of diabetes.

Methods

In the current study, the effects of various probiotics including Lactobacillus reuteri (L reuteri), Lactobacillus crispatus (L crispatus), and Bacillus subtilis on the levels of blood glucose, lipid, and insulin as well as haemoglobin A1c (HbA1c) were investigated in rat models of streptozotocin (STZ)‐induced diabetes and compared with metformin. In addition, GLUT‐4 and PPAR‐γ transcript levels have been analysed in adipose tissues.

Results

A significant decrease in plasma glucose and HbA1c levels and a dramatic increase in insulin levels have been detected after consumption of probiotics. Furthermore, lipid profiles have been improved. The expression of Glut‐4 and Ppar‐γ genes in adipose tissues also increased after treatment period.

Conclusion

The results of this experiment showed that daily consumption of probiotics can be effective in control of STZ‐induced diabetes and its complications.
A global community effort to decipher the unique biology of annual killifish
Authors: Berois Nibia , Garcia Graciela , De Sá Rafael Omar
Published: June 2017

Over the past 50 years, annual killifishes arose as alternative model organisms for studies of vertebrate biology. The annual fish offers exceptional advantages for studies of genetics, genomics, developmental biology, population dynamics, ecology, biogeography, and evolution. They inhabit extremely variable freshwater environments in Africa and South America, have a short lifespan and a set of unique and fascinating developmental characteristics. Embryos survive within the dry substrate during the dry season, whereas the adult population dies. Thus, the survival of the populations is entirely dependent on the buried embryos that hatch the next rainy season. Although Old and New World species share similarities in their life cycle, they also have different adaptive responses associated with climate‐related selective pressures. Therefore, contrasting different species from these areas is essential to understand unique adaptations to heterogeneous environment. A network of laboratories (United States, Czech Republic, Italy, Brazil, Chile, and Uruguay) is working and collaborating on many aspects of the biology of annual fishes. Participating researchers share projects and cross‐training undergraduate and graduate students. These efforts resulted in two International Symposia (2010 and 2015) that took place in Montevideo and an international book. Herein, we summarize the progress made by this global community of scientists. Developmental Dynamics 246:807–811, 2017. © 2017 Wiley Periodicals, Inc.
Stabilizing mechanisms in a food web with an introduced omnivore
Authors: Granados Monica , Duffy Sean , McKindsey Christopher W. , Fussmann Gregor F.
Published: June 2017

Intraguild predation (IGP) is an omnivorous food web configuration in which the top predator consumes both a competitor (consumer) and a second prey that it shares with the competitor. This omnivorous configuration occurs frequently in food webs, but theory suggests that it is unstable unless stabilizing mechanisms exist that can decrease the strength of the omnivore and consumer interaction. Although these mechanisms have been documented in native food webs, little is known about whether they operate in the context of an introduced species. Here, we study a marine mussel aquaculture system where the introduction of omnivorous mussels should generate an unstable food web that favors the extinction of the consumer, yet it persists. Using field and laboratory approaches, we searched for stabilizing mechanisms that could reduce interaction strengths in the food web. While field zooplankton counts suggested that mussels influence the composition and abundance of copepods, stable isotope results indicated that life‐history omnivory and cannibalism facilitated the availability of prey refugia, and reduced competition and the interaction strength between the mussel omnivore and zooplankton consumers. In laboratory experiments, however, we found no evidence of adaptive feeding which could weaken predator–consumer interactions. Our food web study suggests that the impact of an introduced omnivore may not only depend on its interaction with native species but also on the availability of stabilizing mechanisms that alter the strength of those interactions.
Effects of Alpine land‐use changes: Soil macrofauna community revisited
Authors: Steinwandter Michael , Schlick‐Steiner Birgit C. , Seeber Gilg U. H. , Steiner Florian M. , Seeber Julia
Published: June 2017

Although soil invertebrates play a decisive role in maintaining ecosystem functioning, little is known about their structural composition in Alpine soils and how their abundances are affected by the currently ongoing land‐use changes. In this study, we re‐assessed the soil macrofauna community structure of managed and abandoned Alpine pastureland, which has already been evaluated 14 years earlier. Our results confirm clear shifts in the community composition after abandonment, in that (1) Chilopoda and Diplopoda were recorded almost exclusively on the abandoned sites, (2) Coleoptera larvae and Diptera larvae were more abundant on the abandoned than on the managed sites, whereas (3) Lumbricidae dominated on the managed sites. By revisiting managed and abandoned sites, we infer community patterns caused by abandonment such as changes in the epigeic earthworm community structure, and we discuss seasonal and sampling effects. Our case study improves the still limited understanding of spatio‐temporal biodiversity patterns of Alpine soil communities.
Closing the gaps for animal seed dispersal: Separating the effects of habitat loss on dispersal distances and seed aggregation
Authors: Jones Landon R. , Duke‐Sylvester Scott M. , Leberg Paul L. , Johnson Derek M.
Published: June 2017

Habitat loss can alter animal movements and disrupt animal seed dispersal mutualisms; however, its effects on spatial patterns of seed dispersal are not well understood. To explore the effects of habitat loss on seed dispersal distances and seed dispersion (aggregation), we created a spatially explicit, individual‐based model of an animal dispersing seeds (SEADS—Spatially Explicit Animal Dispersal of Seeds) in a theoretical landscape of 0%–90% habitat loss based on three animal traits: movement distance, gut retention time, and time between movements. Our model design had three objectives: to determine the effects of (1) animal traits and (2) habitat loss on seed dispersal distances and dispersion and (3) determine how animal traits could mitigate the negative effects of habitat loss on these variables. SEADS results revealed a complex interaction involving all animal traits and habitat loss on dispersal distances and dispersion, driven by a novel underlying mechanism of fragment entrapment. Unexpectedly, intermediate habitat loss could increase dispersal distances and dispersion relative to low and high habitat loss for some combinations of animal traits. At intermediate habitat loss, movement between patches was common, and increased dispersal distances and dispersion compared to continuous habitats because animals did not stop in spaces between fragments. However, movement between patches was reduced at higher habitat loss as animals became trapped in fragments, often near the parent plant, and dispersed seeds in aggregated patterns. As movement distance increased, low time between movements and high gut retention time combinations permitted more movement to adjacent patches than other combinations of animal traits. Because habitat loss affects movement in a nonlinear fashion under some conditions, future empirical tests would benefit from comparisons across landscapes with more than two levels of fragmentation.
DNA metabarcoding for diet analysis and biodiversity: A case study using the endangered Australian sea lion (Neophoca cinerea)
Authors: Berry Tina E. , Osterrieder Sylvia K. , Murray Dáithí C. , Coghlan Megan L. , Richardson Anthony J. , Grealy Alicia K. , Stat Michael , Bejder Lars , Bunce Michael
Published: June 2017

The analysis of apex predator diet has the ability to deliver valuable insights into ecosystem health, and the potential impacts a predator might have on commercially relevant species. The Australian sea lion (Neophoca cinerea) is an endemic apex predator and one of the world's most endangered pinnipeds. Given that prey availability is vital to the survival of top predators, this study set out to understand what dietary information DNA metabarcoding could yield from 36 sea lion scats collected across 1,500 km of its distribution in southwest Western Australia. A combination of PCR assays were designed to target a variety of potential sea lion prey, including mammals, fish, crustaceans, cephalopods, and birds. Over 1.2 million metabarcodes identified six classes from three phyla, together representing over 80 taxa. The results confirm that the Australian sea lion is a wide‐ranging opportunistic predator that consumes an array of mainly demersal fauna. Further, the important commercial species Sepioteuthis australis (southern calamari squid) and Panulirus cygnus (western rock lobster) were detected, but were present in <25% of samples. Some of the taxa identified, such as fish, sharks and rays, clarify previous knowledge of sea lion prey, and some, such as eel taxa and two gastropod species, represent new dietary insights. Even with modest sample sizes, a spatial analysis of taxa and operational taxonomic units found within the scat shows significant differences in diet between many of the sample locations and identifies the primary taxa that are driving this variance. This study provides new insights into the diet of this endangered predator and confirms the efficacy of DNA metabarcoding of scat as a noninvasive tool to more broadly define regional biodiversity.
Host taxonomy constrains the properties of trophic transmission routes for parasites in lake food webs
Authors: Cirtwill Alyssa R. , Lagrue Clement , Poulin Robert , Stouffer Daniel B.
Published: June 2017

Some parasites move from one host to another via trophic transmission, the consumption of the parasite (inside its current host) by its future host. Feeding links among free‐living species can thus be understood as potential transmission routes for parasites. As these links have different dynamic and structural properties, they may also vary in their effectiveness as trophic transmission routes. That is, some links may be better than others in allowing parasites to complete their complex life cycles. However, not all links are accessible to parasites as most are restricted to a small number of host taxa. This restriction means that differences between links involving host and non‐host taxa must be considered when assessing whether transmission routes for parasites have different food web properties than other links. Here we use four New Zealand lake food webs to test whether link properties (contribution of a link to the predator's diet, prey abundance, prey biomass, amount of biomass transferred, centrality, and asymmetry) affect trophic transmission of parasites. Critically, we do this using both models that neglect the taxonomy of free‐living species and models that explicitly include information about which free‐living species are members of suitable host taxa. Although the best‐fit model excluding taxonomic information suggested that transmission routes have different properties than other feeding links, when including taxonomy, the best‐fit model included only an intercept. This means that the taxonomy of free‐living species is a key determinant of parasite transmission routes and that food‐web properties of transmission routes are constrained by the properties of host taxa. In particular, many intermediate hosts (prey) attain high biomasses and are involved in highly central links while links connecting intermediate to definitive (predator) hosts tend to be dynamically weak.
Non‐random species loss in a forest herbaceous layer following nitrogen addition
Authors: Walter Christopher A. , Adams Mary Beth , Gilliam Frank S. , Peterjohn William T.
Published: June 2017

Nitrogen (N) additions have decreased species richness (S) in hardwood forest herbaceous layers, yet the functional mechanisms for these decreases have not been explicitly evaluated. We tested two hypothesized mechanisms, random species loss (RSL) and non‐random species loss (NRSL), in the hardwood forest herbaceous layer of a long‐term, plot‐scale, fertilization experiment in the central Appalachian Mountains, USA. Using a random thinning algorithm, we simulated changes in species densities under RSL and compared the simulated densities to the observed densities among N‐fertilized (+N), N‐fertilized and limed (+N+L), and reference (REF) plots in regenerating forest stands. We found a lower S in the +N treatment across all survey years and determined that the reduction in S was a function of NRSL. Furthermore, non‐random effects were observed in certain species, as they occurred at densities that were either higher or lower than expected due to RSL. Differential advantages were also observed among species between +N and +N+L treatments, suggesting that species responded to either the fertilization or acidification effects of N, though no consistent pattern emerged. Species nitrophily status was not a useful trait for predicting specific species losses, but was a significant factor when averaged across all treatments and sampling years. Our results provide strong evidence that declines in S in the forest herbaceous layer under N fertilization are due largely to NRSL and not simply a function of species rarity.
Oxygen Activation by Copper Complexes with an Aromatic Bis(guanidine) Ligand
Authors: Strassl Florian , Grimm‐Lebsanft Benjamin , Rukser Dieter , Biebl Florian , Biednov Mykola , Brett Calvin , Timmermann Riccardo , Metz Fabian , Hoffmann Alexander , Rübhausen Michael , Herres‐Pawlis Sonja
Published: June 2017

Combining the new aromatic bis(guanidine) ligand bis(tetramethylguanidino)toluene (TMG2tol) and different copper salts led to four new complexes. The molecular structures were analysed by X‐ray diffraction. Three of the complexes are active in biomimetic activation of oxygen. It is the first time a bis‐µ‐oxido species of an aromatic guanidine copper complex is analysed by Raman and UV/Vis spectroscopy. The formation and decay of the bis(µ‐oxido)dicopper species were investigated at low temperatures up to 273 K by UV/Vis spectroscopy with a stopped‐flow setup. The results showed that the Cu2O2 intermediate of an aromatic guanidine–copper complex decays much faster than most known bis(guanidine) complexes. Moreover, natural bond orbital (NBO) analyses revealed that the aromatic guanidine is the stronger donor compared to the aliphatic one.
A Simple, Efficient and Ultrasensitive Gold Nanourchin Based Electrochemical Sensor for the Determination of an Antimalarial Drug: Mefloquine
Authors: Chiwunze Tirivashe Elton , Thapliyal Neeta Bachheti , Palakollu Venkata Narayana , Karpoormath Rajshekhar
Published: June 2017

Mefloquine (MQ) is a quinoline based antimalarial drug, which is potent against multiple drug‐resistant Plasmodium falciparum. It is widely prescribed for the prophylactic treatment of malaria. Due to extensive usage of MQ, constant monitoring of the drug level in human body is of paramount importancein order to ensure that optimum drug exposure is achieved. The present work describes a gold nanourchins (AuNUs) based electrochemical sensor for the determination of MQ.AuNUs were synthesized via seed‐mediated method and characterized using ultraviolet‐visible spectroscopy, energy‐dispersive X‐ray spectroscopy, field emission scanning electron microscopy, zeta‐sizer and electrochemical techniques (electrochemical impedance spectroscopy and cyclic voltammetry). Fabrication of the sensor was done by drop‐coating the synthesized AuNUs onto a glassy carbon electrode. The fabricated sensor exhibited enhanced voltammetric response, which was attributed to the excellent conductivity and high surface area of AuNUs. Under optimum square wave voltammetric conditions, the sensor displayed two linear response ranges (from 2.0×10−9 to 1.0×10−6 M and from 1.0×10−6 to 1.0×10−3 M) with a detection limit of 1.4 nM. The electrode demonstrated good reproducibility, stability and selectivity over common interferents. The utility of the sensor was successfully assessed for quantification of the drug in pharmaceutical preparation and spiked human urine sample. Thus, the present study demonstrates a promising approach for determination of MQ with practical utility in quality control and clinical analysis.
Electrochemical Cyclization of Adrenaline, the Simplest Derivatization for its Selective Determination
Authors: Rafiee Mohammad , Khalafi Lida , Mousavi Fatemeh , Babaloii Fatemeh , Kalhori Fatemeh
Published: June 2017

Electrochemical techniques are the most reliable techniques for determination of neurotransmitters and selective determination is their most challenging issue. Herein we have optimized the condition for oxidation of adrenaline and noradrenaline, as the most similar neurotransmitters, to find a simple and fast technique for their selective determination. Under mild acidic condition, oxidation of adrenaline is followed by a cyclization reaction and oxidation of the product (ECE mechanism) whereas noradrenaline undergoes just oxidation (E mechanism). The redox potential of the product of ECE mechanism has 350 mV difference with the product of E mechanism. This different in reactivity and redox potential yields two baseline separated reduction peaks for the oxidation products of adrenaline and noradrenaline, which used for their selective determination.
Evaluation of capillary zone electrophoresis for the quality control of complex biologic samples: Application to snake venoms
Authors: Kpaibe André P.S. , Ben‐Ameur Randa , Coussot Gaëlle , Ladner Yoann , Montels Jérôme , Ake Michèle , Perrin Catherine
Published: June 2017

Snake venoms constitute a very promising resource for the development of new medicines. They are mainly composed of very complex peptide and protein mixtures, which composition may vary significantly from batch to batch. This latter consideration is a challenge for routine quality control (QC) in the pharmaceutical industry. In this paper, we report the use of capillary zone electrophoresis for the development of an analytical fingerprint methodology to assess the quality of snake venoms. The analytical fingerprint concept is being widely used for the QC of herbal drugs but rarely for venoms QC so far. CZE was chosen for its intrinsic efficiency in the separation of protein and peptide mixtures. The analytical fingerprint methodology was first developed and evaluated for a particular snake venom, Lachesis muta. Optimal analysis conditions required the use of PDADMAC capillary coating to avoid protein and peptide adsorption. Same analytical conditions were then applied to other snake venom species. Different electrophoretic profiles were obtained for each venom. Excellent repeatability and intermediate precision was observed for each batch. Analysis of different batches of the same species revealed inherent qualitative and quantitative composition variations of the venoms between individuals.