bluuebunny/crossref_metadata_2025 huggingface dataset:
Tuning Ion Complexing To Rapidly Prepare Hollow Ag–Pt Nanowires with High Activity toward the Methanol Oxidization Reaction
Authors: Liu Fangyan , Qi Peimei , Liang Xiaoli , Chen Wei , Li Benxia , Zhang Lijie , Yang Yun , Huang Shaoming
Published: September 2018

Hollow Pt‐based nanowires (NWs) have important applications in catalysis. Their preparation often involves a two‐step process in which M (M=Ag, Pd, Co, Ni) NWs are prepared and subsequently subjected to galvanic reaction in solution containing a Pt precursor. It is challenging to achieve a simple one‐step preparation, because the redox potential of PtIV/Pt or PtII/Pt to Pt is high, and therefore, Pt atoms always form first. This work demonstrates that an appropriate pH can decrease the redox potential of PtIV/Pt and allows the one‐step preparation of high‐quality hollow Pt–Ag NWs rapidly (10 min). Moreover, it is easy to realize large‐scale preparation with this method. The NW composition can be adjusted readily to optimize their performance in the electrocatalytic methanol oxidization reaction (MOR). Compared with commercial Pt/C, NWs with appropriate Ag/Pt ratios exhibit high stability, activity, and CO tolerance ability.
Resolution of isoborneol and its isomers by GC/MS to identify “synthetic” and “semi‐synthetic” borneol products
Authors: Yang Ming‐Yeh , Khine Aye Aye , Liu Jen‐Wei , Cheng Hui‐Chen , Hu Anren , Chen Hao‐Ping , Shih Tzenge‐Lien
Published: September 2018

Borneol is a plant terpene commonly used in traditional Chinese medicine. Optically pure (+)‐borneol and (−)‐borneol can be obtained by extraction from the plants Dipterocarpaceae and Blumea balsamifera, respectively. “Synthetic borneol” is obtained from the reduction of (±)‐camphor to lead to four different stereoisomers: (+)‐isoborneol, (−)‐isoborneol, (+)‐borneol, and (−)‐borneol. In contrast, “semi‐synthetic borneol” is produced from the reduction of natural camphor, (+)‐camphor, to afford two isomers: (−)‐isoborneol and (+)‐borneol. We established a convenient method to identify them by treating the four stereoisomers with two chiral reagents, (R)‐(+)‐α‐methoxy‐α‐trifluoromethylphenylacetyl chloride ((R)‐(+)‐MTPA‐Cl) and (1S)‐(−)‐ camphanic chloride. The resulting derivatives from the above mentioned method were analyzed by gas chromatography. The enantiomers of (+)‐ and (−)‐isoborneol were successfully separated from (+)‐ and (−)‐borneol isomers in this study to make this a useful method in the identification of “synthetic” and “semi‐synthetic” borneols. Furthermore, we also examined five different commercial borneols. During this course, a novel and unprecedented partial epimerization from isoborneol‐camphanic ester to borneol‐camphanic ester was observed. However, this phenomenon did not occur in isoborneol‐MTPA esters epimerization to borneol‐MTPA case under the same conditions. The DFT calculation of activation energies for both reactions was in a good agreement with the results obtained from GC analysis.
Aerobic Bacterial Degraders With Their Relative Pathways for Efficient Removal of Individual BTEX Compounds
Authors: Yavas Alper , Icgen Bulent
Published: September 2018

Benzene, toluene, ethylbenzene, and xylene (BTEX) compounds are of great environmental concern due to their toxicity and carcinogenicity. Bacterial removal of BTEX has proven to be highly efficient, cost‐effective, and non‐disruptive, provided that, efficient bacterial degraders are available. The objective of this study, therefore, is to discover aerobic bacterial degraders with their relative pathways that could be employed for the efficient removal of individual BTEX compounds. A total of 22 petroleum hydrocarbon degrading aerobic bacteria from the river water in close vicinity to a petrol refinery were isolated and identified previously. These bacteria were further screened for their potential to degrade individual BTEX compounds. Primary selection of BTEX degraders was carried out by using conventional enrichment culture technique and gas chromatography/mass spectrophotometry (GC/MS) analyses. Out of the 22 isolates, five were found to degrade BTEX efficiently and further characterized through PCR analyses for their initial attack and cleavage genes as well as GC/MS analyses of the intermediate metabolites to decipher the degradation pathways used. The study elucidates new efficient bacterial strains of Acinetobacter calcoaceticus Fe10, Serratia nematodiphila Mn11, Raoultella planticola Ag11, Pseudomonas koreensis Hg11, and Micrococcus luteus Sr11 with their relative pathways for aerobic removal of the individual BTEX compounds.
L1, Lp, L2, and elastic net penalties for regularization of Gaussian component distributions in magnetic resonance relaxometry
Authors: Sabett Christiana , Hafftka Ariel , Sexton Kyle , Spencer Richard G.
Published: September 2018

Determination of the distribution of magnetic resonance (MR) transverse relaxation times is emerging as an important method for materials characterization, including assessment of tissue pathology in biomedicine. These distributions are obtained from the inverse Laplace transform (ILT) of multiexponential decay data. Stabilization of this classically ill‐posed problem is most commonly attempted using Tikhonov regularization with an L2penalty term. However, with the availability of convex optimization algorithms and recognition of the importance of sparsity in model reconstruction, there has been increasing interest in alternative penalties. The L1penalty enforces a greater degree of sparsity than L2, and so may be suitable for highly localized relaxation time distributions. In addition, Lppenalties, 1 < p < 2, and the elastic net (EN) penalty, defined as a linear combination of L1and L2penalties, may be appropriate for distributions consisting of both narrow and broad components. We evaluate the L1, L2, Lp, andENpenalties for model relaxation time distributions consisting of two Gaussian peaks. For distributions with narrow Gaussian peaks, the L1penalty works well to maintain sparsity and promote resolution, while the conventional L2penalty performs best for distributions with broader peaks. Finally, the LpandENpenalties do in fact outperform the L1and L2penalties for distributions with components of unequal widths. These findings serve as indicators of appropriate regularization in the typical situation in which the experimentalist has a priori knowledge of the general characteristics of the underlying relaxation time distribution. Our findings can be applied to both the recovery of T2distributions from spin echo decay data as well as distributions of otherMRparameters, such as apparent diffusion constant, from their multiexponential decay signals.
Variational Bayesian analysis of nonuniformly sampled NMR data
Authors: Worley Bradley
Published: September 2018

Nonuniform sampling (NUS) offers NMR spectroscopists a means of accelerating data collection and increasing spectral quality in multidimensional (nD) experiments. The data from NUS experiments are incomplete by design, and must be reconstructed prior to use. While most existing reconstruction techniques compute point estimates of the true signal, Bayesian statistics offers a means of estimating posterior distributions over the signal, which enable more rigorous quantitation and uncertainty estimation. In this article, we describe the variational approach to approximating Bayesian posterior distributions, and illustrate how it can be applied to extend existing results from Bayesian spectrum analysis and compressed sensing. The new NUS reconstruction algorithms resulting from variational Bayes are computationally efficient, and offer new insights into the concepts of spectral sparsity and optimal sampling in NMR experiments.
Probing the Interfaces in Nanosilica‐Supported TiO2 Photocatalysts by Solid‐State NMR and In Situ FTIR
Authors: Singh Rustam , Bayal Nisha , Maity Ayan , Pradeep D. Jeiyendira , Trébosc Julien , Madhu P. K. , Lafon Olivier , Polshettiwar Vivek
Published: September 2018

Although the range of photocatalysts with controllable size, shape and morphology has developed in recent years with a large number of silica‐supported TiO2 catalysts, the details of photocatalytic interfaces between nanosilica and TiO2 them and the mechanisms of TiO2 functionalization of silica surfaces are not yet well understood. It is worth mentioning that the understanding of a mechanism from a molecular point of view has always been a challenge in the field of materials science. Here, we probe interfaces in (dendritic fibrous nano‐silica (DFNS) supported TiO2 photocatalysts as well as propose and prove the formation mechanism of the photocatalyst, DFNS/TiO2, by ammonia‐assisted functionalization of DFNS by titanium butoxide (TBOT). The proposed formation mechanism includes the following steps: i) the deprotonation of silica surface (silanols) by ammonia and the hydrolysis of TBOT to titanium hydroxide [Ti(OH)4], ii) the donation of electron lone pair from ammonia to the Ti4+ ion of Ti(OH)4, iii) the release of hydroxide ions, followed by hetero‐condensation of dehydroxylated titanium ions with the deprotonated silanols, generating Si−O−Ti oxobridges, iv) the formation of oxy‐anion of titanols and its reaction with another molecule of ammonia‐activated titanium hydroxide to generate Ti−O−Ti oxobridges, and v) the continuation of the above cycle of steps until the titanium hydroxide precursor is consumed to produce silica supported titanium hydroxide. During thermal treatment, the titanols condense, yielding DFNS/TiO2 photocatalysts. To prove this mechanism, detailed solid‐state 1H, 29Si, 47,49Ti NMR and in situ FTIR studies were carried out, based on which different surface species formed during TiO2 growth on DFNS were identified. This has led to fundamental insights into the reaction of TBOT with DFNS silica surface and interfaces between DFNS and TiO2.
Multienzyme‐Mimicking Nanocomposite for Tumor Phototheranostics and Normal Cell Protection
Authors: Zhen Wenyao , Wang Wei , Ma Zhifang , Bai Jing , Jia Xiaodan , Ruan Yudi , Wang Chao , Zhang Mengchao , Jiang Xiue
Published: September 2018

Selectively regulating the reactive oxygen species (ROS) level in cells by redox modulation with nanoparticles mimicking multiple enzymes holds great promise for protecting normal cells against ROS threats and surpassing the current limitations of ROS‐dependent cancer therapy. Herein, we develop a new indocyanine green (ICG)‐bovine serum albumin (BSA)‐cerium‐manganese oxide nanocomposites (IBCM NCs) via facile one‐step biomineralization to functionally mimic superoxide dismutase and catalase. IBCM NCs can synergistically regulate superoxide, hydrogen peroxide, oxygen and glutathione levels in cancer cells as well as provide contrast for magnetic resonance imaging. Consequently, cancer hypoxia can be relieved, and the phototherapy efficiency can be dramatically enhanced, leading to a complete ablation of tumor under NIR laser irradiation. On the other hand, IBCM NCs can consume the superoxide and hydrogen peroxide in the normal cells to protect them against ROS threats. Our results demonstrate IBCM NCs can effectively resist ROS threats in normal cells and kill cancer cells through breaking the intracellular redox balance.
Exploration of the dialogue components in Avatar Therapy for schizophrenia patients with refractory auditory hallucinations: A content analysis
Authors: Dellazizzo Laura , Percie du Sert Olivier , Phraxayavong Kingsada , Potvin Stéphane , O'Connor Kieron , Dumais Alexandre
Published: September 2018

Auditory verbal hallucinations are hallmark symptoms of schizophrenia and are amongst the most disturbing symptoms of the disorder. Although not entirely understood, the relationship between the voice hearer and their voices has been shown to be an important treatment target. Understanding voice hearers' standpoints through qualitative analysis is central to apprehend a deeper comprehension of their experience and further explore the relevance of interpersonal interventions. Compared with other dialogical intervention, virtual reality‐assisted therapy (Avatar Therapy) enables patients to be in a tangible relation with a representation of their persecutory voice. This novel therapy has shown favourable results, though the therapeutic processes remain equivocal. We consequently sought to begin by characterizing the main themes emerging during the therapy by exploring the hearer's discussion with their avatar. The therapy sessions of 12 of our referrals were transcribed, and the patients' responses were analysed using content analysis methods. Five themes emerged from data saturation: emotional responses to the voices, beliefs about voices and schizophrenia, self‐perceptions, coping mechanisms, and aspirations. All patients had at least one element within each of these themes. Our analyses also enabled us to identify changes that were either verbalized by the patients or noted by the raters throughout therapy sessions. These findings are relevant as they allowed to identify key themes that are hypothesized to be related to therapeutic targets in a novel relational therapy using virtual reality. Future studies to further explore the processes implicated within Avatar Therapy are necessary.
Rifampicin Alters Metformin Plasma Exposure but Not Blood Glucose Levels in Diabetic Tuberculosis Patients
Authors: te Brake Lindsey H.M. , Yunivita Vycke , Livia Resvi , Soetedjo Nanny , van Ewijk‐Beneken Kolmer Eleonora , Koenderink Jan B. , Burger David M. , Santoso Prayudi , van Crevel Reinout , Alisjahbana Bachti , Aarnoutse Rob E. , Ruslami Rovina ,   on behalf of the TANDEM Consortium
Published: September 2018

The pharmacokinetic (PK) and clinical implications of combining metformin with rifampicin are relevant to increasing numbers of patients with diabetic tuberculosis (TB) across the world and are yet unclear. We assessed the impact of rifampicin on metformin PKs and its glucose‐lowering effect in patients with diabeticTBby measuring plasma metformin and blood glucose during and afterTBtreatment. Rifampicin increased metformin exposure: plasma area under the plasma concentration‐time curve from time point 0 to the end of the dosing interval (AUC0–τ) and peak plasma concentration (Cmax) geometric mean ratio (GMR; during vs. afterTBtreatment) were 1.28 (90% confidence interval (CI) 1.13–1.44) and 1.19 (90%CI1.02–1.38;n = 22). The metformin glucose‐lowering efficacy did not change (Δglucose − Cmax;P = 0.890;n = 18). Thus, we conclude that additional glucose monitoring in this population is not warranted. Finally, 57% of patients on metformin and rifampicin, and 38% of patients on metformin alone experienced gastrointestinal adverse effects. Considering this observation, we advise patients to take metformin and rifampicin with food and preferably separated in time. Clinicians could consider metoclopramide if gastrointestinal adverse effects occur.
Joint low‐complexity equalization and carrier frequency offset compensation for underwater acoustic OFDM communication systems with banded‐matrix approximation at different channel conditions
Authors: Ramadan Khaled , Dessouky Moawad I. , Elkordy Mohamad , Elagooz Salah , Abd El‐Samie Fathi E.
Published: September 2018

Underwater acoustic wireless communication is considered as one of the most challenging communication technologies due to low propagation speed, water salinity, water depth, PH degree, and water temperature. Equalization is one of the means to improve the system performance. Matched filter (MF), zero forcing (ZF), and minimum mean square error (MMSE) equalizers can be used for channel equalization. Unfortunately, the performance of the matched filter is destroyed in the Multiple‐Input Multiple‐Output (MIMO) configurations. In addition, the ZF equalizer suffers from noise enhancement and high complexity because of the direct matrix inversion. On the other hand, the MMSE equalizer requires estimating the operating signal‐to‐noise ratio (SNR) to work properly. In this paper, we present a joint low‐complexity regularized ZF equalizer and carrier frequency offset (CFO) compensation scheme to deal with these problems. The proposed equalization algorithm mitigates the noise enhancement problem using a constant regularization parameter, and it can be implemented with low complexity using the banded‐matrix approximation. Also, we test the performance of the proposed system at different channel conditions. Simulation results show that the proposed equalizer has the ability to enhance the system performance with lower complexity than those of the other equalization algorithms at different channel conditions.
Energy efficient scalability of three level hexagonal heterogeneous broad transmission distance protocol (3L‐HEXA‐HTBTDP) for WSN‐IoT networks
Authors: Shrivastav Khyati , Kulat Kishore D.
Published: September 2018

Multilevel heterogeneity is the present demand of wireless sensor networks as well as internet‐of‐things for balanced energy consumption of the network systems. In this paper, three level hexagonal heterogeneous broad transmission distance protocol (3L‐HEXA‐HTBTDP) is introduced for increasing the energy efficiency of the network. Normal, advanced, and superadvanced sensor nodes in a hexagonal field represent three level heterogeneity. These nodes are elected as cluster heads (CHs) on the basis of new thresholds, thus transferring the collected data to the base station. The protocol is beneficial in cellular communication and web‐of‐things applications to fulfill the high energy requirements of the wireless systems. The scalability is done here for perceiving the differences in the application of proposed algorithm 3L‐HEXA‐HTBTDP on different number of sensor nodes with variable values of initial energies. This is a promising approach to achieve reliable communication, coverage, and connectivity among sensor nodes of the hexagonal field. The scheme is evaluated through exhaustive simulation using Matlab. It is compared with the previous approaches of clustering implemented on the hexagonal field. Different performance parameters like alive node metrics, stability period, network lifetime, residual energy, and variance of energy are used for benchmarking the results of 3L‐HEXA‐HTBTDP with three level hexagonal stable election protocol (3L‐HEXA‐SEP) and three level hexagonal energy efficient heterogeneous clustered scheme (3L‐HEXA‐EEHC). In general, it is observed that the proposed 3L‐HEXA‐HTBTDP outperforms other existing protocols.
Neuroprotection of rhGLP‐1 in diabetic rats with cerebral ischemia/reperfusion injury via regulation of oxidative stress, EAAT2, and apoptosis
Authors: Fang Yi , Jiang Daoli , Wang Yitong , Wang Qian , Lv Dongmei , Liu Jichao , Liu Chang
Published: September 2018

Preclinical Research & Development

The purpose of the present study is to evaluate the neuroprotective effect of recombinant human glucagon‐like peptide‐1 (rhGLP‐1) as well as to explore corresponding mechanisms in diabetic rats with cerebral ischemia/reperfusion injury induced by middle cerebral artery occlusion (MCAO). Diabetes mellitus was induced by intraperitoneal injection of streptozotocin. The rats were pretreated with rhGLP‐1 (20 μg/kg intraperitoneally, thrice a day) for 14 days. Thereafter, the rats were subjected to MCAO 90 min/reperfusion 24 hr. At 2 and 24 hr of reperfusion, the rats were assessed for neurological deficits and subsequently executed for the evaluation of cerebral infarct volume, oxidative stress parameters, and the expression of excitatory amino acid transporter 2 (EAAT2) and apoptotic markers. Results indicate that rhGLP‐1 significantly ameliorated neurological deficits and reduced cerebral infarct volume in diabetic MCAO rats. In addition, oxidative stress parameters in ischemic penumbra were significantly alleviated in rhGLP‐1‐pretreated diabetic MCAO rats. rhGLP‐1 significantly upregulated the ratio of Bcl‐2/Bax and EAAT2 expression and downregulated cleaved caspase‐3 expression in ischemic penumbra of diabetic MCAO rats. Our results suggest that rhGLP‐1 could significantly ameliorate neurological deficits and reduce cerebral infarct volume in diabetic MCAO rats, which may be due to the inhibition of oxidative stress and apoptosis and the promotion of EAAT2 expression.
Actinomycin‐D and dimethylamino‐parthenolide synergism in treating human pancreatic cancer cells
Authors: Lamture Gauri , Crooks Peter A. , Borrelli Michael J.
Published: September 2018

Preclinical Research & Development

Pancreatic cancer is the third leading cause of death in the US with a poor 5‐year survival rate of 8.5%. A novel anti‐cancer drug, dimethylamino parthenolide (DMAPT), is the water‐soluble analog of the natural sesquiterpene lactone, parthenolide. The putative modes of action of DMAPT are inhibition of the Nuclear chain factor kappa‐light‐chain enhancer of activated B cells (NFκB) pathway and depletion of glutathione levels; the latter causing cancer cells to be more susceptible to oxidative stress‐induced cell death. Actinomycin‐D (ActD) is a polypeptide antibiotic that binds to DNA, and inhibits RNA and protein synthesis by inhibiting RNA polymerase II. A phase 2 clinical trial indicated that ActD could be a potent drug against pancreatic cancer; however, it was not a favored drug due to toxicity issues. New drug entities and methods of drug delivery, used alone or in combination, are needed to treat pancreatic cancer more effectively. Thus, it was postulated that combining DMAPT and ActD would result in synergistic inhibition of Panc‐1 pancreatic cancer cell growth because DMAPT's inhibition of NFκB would enhance induction of apoptosis by ActD, via phosphorylation of c‐Jun, by minimizing NFκB inhibition of c‐Jun phosphorylation. Combining these two drugs induced a higher level of cell death than each drug alone. A fixed drug ratio of DMAPT: ActD (1,200:1) was used. Data from metabolic (MTT) and colony formation assays were analyzed for synergism with CompuSyn software, which utilizes the Chou‐Talalay equation. The analyses indicated synergism and moderate synergism at combination concentrations of DMAPT/ActD of 12/0.01 and 18/0.015 μM, respectively.
The compound 2‐(naphthalene‐2‐thio)‐5,8‐dimethoxy‐1,4‐naphthoquinone induces apoptosis via reactive oxygen species‐regulated mitogen‐activated protein kinase, protein kinase B, and signal transducer and activator of transcription 3 signaling in human gastric cancer cells
Authors: Wang Jia‐Ru , Shen Gui‐Nan , Luo Ying‐Hua , Piao Xian‐Ji , Shen Meng , Liu Chang , Wang Yue , Meng Ling‐Qi , Zhang Yi , Wang Hao , Li Jin‐Qian , Xu Wan‐Ting , Liu Yang , Sun Hu‐Nan , Han Ying‐Hao , Jin Mei‐Hua , Cao Long‐Kui , Jin Cheng‐Hao
Published: September 2018

Hit, Lead & Candidate Discovery

It is reported that 1,4‐naphthoquinones and their derivatives have potent antitumor activity in various cancers, although their clinical application is limited by observed side effects. To improve the therapeutic efficacy of naphthoquinones in the treatment of cancer and to reduce side effects, we synthesized a novel naphthoquinone derivative, 2‐(naphthalene‐2‐thio)‐5,8‐dimethoxy‐1,4‐naphthoquinone (NTDMNQ). In this study, we explored the effects of NTDMNQ on apoptosis in gastric cancer cells with a focus on reactive oxygen species (ROS) production. Our results demonstrated that NTDMNQ exhibited the cytotoxic effects on gastric cancer cells in a dose‐dependent manner. NTDMNQ significantly induced mitochondrial‐related apoptosis in AGS cells and increased the accumulation of ROS. However, pre‐treatment with N‐acetyl‐L‐cysteine (NAC), an ROS scavenger, inhibited the NTDMNQ‐induced apoptosis. In addition, NTDMNQ increased the phosphorylation of p38 kinase and c‐Jun N‐terminal kinase (JNK) and decreased the phosphorylation of extracellular signal‐regulated kinase (ERK), protein kinase B (Akt), and Signal Transducer and Activator of Transcription 3 (STAT3); these effects were blocked by mitogen‐activated protein kinase (MAPK) inhibitor and NAC. Taken together, the present findings indicate that NTDMNQ‐induced gastric cancer cell apoptosis via ROS‐mediated regulation of the MAPK, Akt, and STAT3 signaling pathways. Therefore, NTDMNQ may be a potential treatment for gastric cancer as well as other tumor types.
Anger, sad, and blended expressions to contingency disruption in young infants
Authors: Sullivan Margaret W.
Published: September 2018

Three studies elicited young infants’ (aged 17–23 weeks) anger and sad facial expressions during brief contingency disruptions to explore their potential organization over time as a biphasic process. Study 1 examined partial correlations among anger, sad, blended anger/sad, and neutral expressions during extinction in three extant, independently recruited samples. Across samples, all three negative expressions were inversely related to neutral expressions, but anger and sad expressions were not significantly correlated when anger/sad blends were controlled. Study 2 compared expressions during contingency and disruption minutes in two groups: one in which the disruption was an extinction phase (the absence of the formerly contingent event), or one in which the disruption was noncontingent presentations of the stimuli. Study 3 examined expression trajectories over time in two contingency and extinction sessions. Independent trajectories of anger and sad expressions occurred over time in Studies 2 and 3. Extinction and noncontingency differed in sad expression. The relation between expressions and blends also varied over time.
Functional diversity changes over 100 yr of primary succession on a volcanic island: insights into assembly processes
Authors: Karadimou E. , Kallimanis A. S. , Tsiripidis I. , Raus T. , Bergmeier E. , Dimopoulos P.
Published: September 2018

Changes in species diversity following volcanic eruptions have been studied extensively, but our knowledge on functional diversity and community assembly under such conditions is very limited. Here, we study the processes following the destruction of vegetation after a volcanic eruption. Specifically, we investigate (1) the temporal patterns of taxonomic and functional diversity over time since a previous eruption (alpha diversity) and beta diversity, (2) the temporal patterns of 26 individual traits (vegetative characteristics, plant taxa ecological preferences, and regenerative characteristics) providing more detailed information on species strategies at the initial and later stages of succession, and (3) the processes driving species assembly and whether they changed over time since the eruption an eruption. We analyzed data recorded during five floristic censuses that took place between 1911 and 2011, calculated alpha and beta facets of taxonomic and functional diversity and examined how community structure changed over time, using 26 functional characteristics, based on their ability to discern primary from later colonists, including longevity, growth form, Ellenberg's indicator values, seed production and weight, flower size and sex, pollination type, and dispersal mode. Null model analysis was used to test whether the observed functional diversity deviates from random expectations. Alpha diversity, both taxonomic and functional, increased over time after an eruption, while beta diversity did not display a clear trend. This finding indicates that mainly abiotic processes determine species assembly over time after an eruption (at least for the time span studied here), contrary to theoretical expectations. It is most interesting that, simultaneously, some aspects of diversity indicated the effect of biotic interactions (facilitation and competition) on the assembly of species a few years after an eruption. This finding implies a legacy effect, since a high percentage of perennial species was noticed in the assemblage right after the eruption, as well as the effect of the harsh environmental conditions on the assembly of the plant communities. In conclusion, our results indicate the role of legacy effects in succession (most probably through the survival of underground plant parts) and underline the importance of disturbance history in providing the context needed for understanding effects of past events on succession.
A causal partition of trait correlations: using graphical models to derive statistical models from theoretical language
Authors: Cronin James Patrick , Schoolmaster Donald R.
Published: September 2018

Recent studies hypothesize various causes of species‐level trait covariation, namely size (e.g., metabolic theory of ecology and leaf economics spectrum), pace‐of‐life (e.g., slow‐to‐fast continuum; lifestyle continuum), evolutionary history (e.g., phylogenetic conservatism), and ecological conditions (e.g., stabilizing selection). Various methods have been used in attempts to partition trait correlation among these influences (e.g., univariate analysis, principal components analysis, and factor analysis). However, it is not clear that the implied causal structure assumed by these methods matches the hypothesized causal structure driving trait correlations, a situation that can potentially lead to biased estimates and incorrect partitioning among mechanisms. Here, we propose the application of graphical causal models (GCM) for across‐kingdom synthesis and to aid researchers in their selection of correct analytical strategies. Graphical causal models use causal diagrams (i.e., box‐and‐arrow graphs) to represent expert knowledge of the data‐generating processes to analytically investigate the possibility of identifying hypothesized causal associations. We developed a causal diagram that synthesizes prominent hypotheses of trait covariation. Using the causal diagram, we (1) derived a quantitative expression to partition trait covariance among its hypothesized causal elements (i.e., size, pace‐of‐life, evolutionary history, and ecological conditions) and (2) developed analytic strategies to attribute trait covariance among the hypothesized causal elements under real‐world data availability, namely unobserved variables (i.e., pace‐of‐life) and confounding variables (i.e., evolutionary history and ecological conditions). Finally, we tested each analytic strategy by simulating trait datasets and, after incorporating the data limitations, tested their ability to correctly partition trait covariance. The analytical strategies were able to correctly partition trait covariance into the hypothesized causal elements of size, pace‐of‐life, and the historical effects of evolutionary history and ecological conditions. We demonstrate the efficacy of these strategies by applying them to a widely used trait dataset. Overall, the application of GCM revealed that researchers have used inappropriate measures to represent their theoretical constructs and have relied on analytical strategies that violated their causal assumptions, likely resulting in biased estimates. We discuss how this mismatch between theoretical language and statistical methods is prevalent in species‐level, trait‐based research and call for future studies to address these limitations.
Coordination Chemistry of N‐(2‐Pyridylethyl)‐Substituted Bulky Amidinates and Triazenides of Magnesium
Authors: Kalden Diana , Krieck Sven , Görls Helmar , Westerhausen Matthias
Published: September 2018

The amidines Dipp‐N=C(R)‐NH(C2H4R′) [R = tBu, R′ = Ph (1a); R = Ph, R′ = Py (1b)] as well as 1‐(2,4,6‐triisopropylphenyl)‐3‐(2‐pyridylethyl)triazene (1c) are magnesiated with commercially available dibutylmagnesium yielding the complexes [(thf)Mg{Dipp‐N=C(tBu)‐N(C2H4Ph)}2] (3a), [Mg{Dipp‐N=C(Ph)‐N(C2H4Py)}2] (3b), and [Mg{Tripp‐N=N‐N(C2H4Py)}2] (3c). Handling and isolation of triazene 1c has been performed at room temperature or below to avoid elimination of dinitrogen and formation of 2‐pyridylethyl‐(2,4,6‐triisopropylphenyl)amine (2). In the solid state, the compounds 1b and 1c form dimers via intermolecular hydrogen bridges to the pyridyl groups of neighbouring molecules.
The Reactivity of Enantiopure (S)‐6‐Oxopipecolic Acid and Corresponding Pyridoisoquinolines Under Acidic Conditions
Authors: Šafář Peter , Marchalín Štefan , Balónová Barbora , Šoral Michal , Moncol Ján , Ghinet Alina , Rigo Benoît , Daïch Adam
Published: September 2018

Enantiopure N‐benzyl 6‐oxopipecolic acid, obtained from (S)‐2‐aminoadipic acid, was evaluated under π‐cationic cyclization conditions. If the combination of SOCl2/AlCl3 seems to be superior in terms of the reaction yields, use of PPA, (CF3CO)2O/BF3·Et2O, and Eaton's reagent is also very interesting since in addition to the expected keto‐lactam, reduced‐ and oxidized keto‐lactam, enamides and enamidones containing CF3CO– residue are isolated. Mechanisms leading to these products as well as the ones resulting from their acidic treatment were proposed and discussed with the help, in some cases, of univocal transformations and X‐ray analysis.
Asymmetric Synthesis of α‐Amino Phosphonates by Using Cinchona Alkaloid‐Based Chiral Phase Transfer Catalyst
Authors: Li Weihua , Wang Yifeng , Xu Danqian
Published: September 2018

A highly enantioselective nucleophilic addition of phosphite esters to imines catalyzed by a chiral phase‐transfer catalyst has been developed. The process affords the hydrophosphonylation of imine products with quaternary stereocenters in good to high yields (up to 95 % yield) and excellent enantioselectivities (up to 99 % ee).
Optimizing Amine‐Mediated Alkyne–Allene Isomerization to Improve Benzannulation Cascades: Synergy between Theory and Experiments
Authors: dos Passos Gomes Gabriel , Morrison Alec E. , Dudley Gregory B. , Alabugin Igor V.
Published: September 2018

A synergy between theory and experiments leads to a milder protocol for base‐mediated high‐temperature benzannulation of alkynylpyridine substrates. Computational analysis identifies mechanistic and energetic nuances in the previously postulated 1,3‐proton transfer isomerization which results in replacement of DBU with a bicyclic guanidine, 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD). We have also outlined the general stereoelectronic and geometric hurdles for the design of 1,3‐proton transfer catalysts. Considerable reductions in time, temperature, and equivalents of base underscore the potential of computational analysis to impact experimental design in the laboratory.
C‐Bridged Bispyrrolidines and Bispiperidines as New Ligands
Authors: Stumpf Tim‐Daniel J. , Steinbach Manfred , Höltke Magdalene , Heuger Gerold , Grasemann Franka , Fröhlich Roland , Schindler Siegfried , Göttlich Richard
Published: September 2018

The preparation of methylene‐bridged C2‐symmetric nitrogen‐heterocycles as a new class of ligands is described, including methylene‐bridged pyridines, quinolones, piperidines and pyrrolidines. These methylene‐bridged aromatic systems are obtained via a microwave assisted Ziegler‐type reaction. The separation of diastereomers and the application of the copper complexes of these ligands for cyclopropanation reactions proves the applicability of these new types of ligands.
Syntheses of a Pair of Simplified Model Compounds of the Dihydroxycyclopentenone Core of the Kodaistatins A–D
Authors: Peter David , Brückner Reinhard
Published: September 2018

The kodaistatins A–D (1–4) are natural products from Aspergillus terreus with the potential of representing leads for a novel cure of type‐2 diabetes. They possess an unusually and highly substituted dihydroxycyclopentenone core. Whether its OH groups are cis‐ or trans‐configured remained unknown by spectroscopy. Previous syntheses of kodaistatin model compounds (cis‐5, cis‐ and trans‐6) allowed to make NMR comparisons with kodaistatin A (1). They led to the insight that the natural product 1 must be a trans‐diol. These findings are corroborated by the synthesis and ensuing NMR study of another pair of cis/trans‐isomeric kodaistatin models (cis‐ and trans‐7) described here. Its first key‐step was a syn‐selective aldol addition. An oxidation/reduction sequence allowed reaching to the corresponding anti‐aldol. Each aldol furnished a kodaistatin model in eight additional steps. The most noteworthy transformation was an SmII‐induced intramolecular aldolization of a bromodiketone.
Electrokinetics with blood
Authors: Chakraborty Suman
Published: September 2018

Microfluidics based lab‐on‐a‐chip technology holds tremendous promises towards point‐of‐care diagnosis of diseases as well as for developing engineered devices aimed towards replicating the intrinsic functionalities of human bodies as mediated by blood vessel mimicking circulatory networks. While the analysis of transport of blood including its unique cellular constituents has remained to be the focus of many reported studies, a progressive interest on understanding the interplay between electric field and blood flow dynamics has paved a new way towards further developments from scientific engineering as well as clinical viewpoint. Here, we briefly outline the interconnection between electrokinetics and blood flow through micro‐capillaries, in an effort to address several challenging propositions in a wide variety of applications encompassing biophysical transport to medical diagnostics. We first present the fundamentals of interaction of electric field with cellular components. In conjunction with the unique rheological features of blood, we show that this interaction may turn out to be compelling for the use of electric fields for transporting blood samples through microfluidic conduits. We discuss the perspectives of both direct current and alternating current electrokinetics in the context of blood flow. In addition, we provide a brief outline of the concerned theoretical developments. We also bring out the relevant biophysical perspectives and focus on applications such as blood plasma separation and separation of circulatory tumor cells. Finally, we attempt to provide a futuristic outlook and envisage the potential of combining electrokinetics with blood microcirculation towards developing futuristic biomimetic microdevices that can replicate a novel control mechanism over micro‐circulatory transport in the entire connective network of human bodies. This may effectively pave the way towards the realization of a next‐generation medical simulation device, significantly advanced from what is available under the ambit of the state of art technology in the field.
Earthquake response analysis of yielding structures coupled with vertically restrained rocking walls
Authors: Aghagholizadeh Mehrdad , Makris Nicos
Published: September 2018

This paper investigates the inelastic response of a yielding structure coupled with a vertically restrained rocking wall. The paper first derives the nonlinear equations of motion of a yielding oscillator coupled with a vertically restrained rocking wall, and the dependability of the one‐degree of freedom idealization is validated against the nonlinear time‐history response analysis of a well‐known nine‐story moment‐resisting steel frame that is coupled with a stepping, vertically restrained rocking wall. While, the coupling of weak building frames with rocking walls is an efficient strategy that controls inelastic deformations by enforcing a uniform interstory‐drift distribution, therefore, avoiding mid‐story failures, the paper shows that even for medium‐rise buildings the effect of vertical tendons on the inelastic structural response is marginal, with the exception of increasing the vertical reactions at the pivoting points of the rocking wall. Accordingly, the paper concludes that for medium‐rise to high‐rise buildings, vertical tendons in rocking walls are not beneficial.
Nonstationarity driven by multidecadal change in catchment groundwater storage: A test of modifications to a common rainfall–run‐off model
Authors: Grigg Andrew H. , Hughes Justin D.
Published: September 2018

Many parts of the world are experiencing a drying climatic trend with significant implications for water resources, especially where there is interaction between surface water and groundwater. Where drying leads to a shift in a catchment's hydrological regime, hydrological models may display bias in predictions and therefore degradation in their predictive capacity. We present two modifications to GR4J, a commonly used rainfall–run‐off model, that (a) allow the sensitivity of storage dependant evaporation and streamflow production to differ significantly, effectively mimicking “catchment memory” and (b) account for temporal variation in catchment vegetation cover, for example, due to land use change. We test the original and two modified models on a forested headwater catchment in the south‐west of Australia. In this catchment, a data set of more than 21,000 individual groundwater records collected over a period of more than 40 years chronicles a significant decline in catchment groundwater storage, resulting in a nonstationary streamflow regime. These longer‐term changes were overlaid with a shorter‐term hydrological response to clearing for bauxite mining and subsequent revegetation. The model structural modifications led to substantially improved streamflow prediction when compared with the original model, related to improved ability in the revised models' production store to match changes in the observed groundwater storage within the catchment. The performance of all three models and hence the apparent effectiveness of the modified models was dependent on the hydrological conditions in the calibration period. Best model fits were obtained when the calibration period encompassed both wetter and drier conditions in the hydrological record. The modified models presented here may reduce prediction bias for catchments in other parts of the world where long‐term shifts in hydrologic regime are being experienced and improve prediction for catchments with significant changes in vegetation cover.
The interplay between chemical speciation and physiology determines the bioaccumulation and toxicity of Cu(II) and Cd(II) to Caenorhabditis elegans
Authors: Moyson Sofie , Town Raewyn M. , Joosen Steven , Husson Steven J. , Blust Ronny
Published: September 2018

Using the well‐documented model organism Caenorhabditis elegans, a combined analysis of metal speciation in the exposure medium and body burdens of metals (Zn, Cu and Cd) was performed, and factors that are predictive of toxicological endpoints in single metal and mixed metal exposures were identified. Cu, and to a lesser extent Cd, is found to associate with Escherichia coli in the exposure medium (the food source for C. elegans) as evidenced by the observed decrease in both their dissolved and free metal ion concentrations. Together with a critical analysis of literature data, our results suggest that free metal ion concentrations and thus aqueous uptake routes are the best predictor of internal concentrations under all conditions considered, and of metal toxicity in single metal exposures. Additional factors are involved in determining the toxicity of metal mixtures. In general, the eventual adverse effects of metals on biota are expected to be a consequence of the interplay between chemical speciation in the exposure medium, timescale of exposure, exposure route as well as the nature and timescale of the biotic handling pathways.
Comprehensive analysis of predictive factors for rapid angiographic stenotic progression and restenosis risk in coronary artery disease patients underwent percutaneous coronary intervention with drug‐eluting stents implantation
Authors: Wu Yanqiang , Fu Xianghua
Published: September 2018

Background

This study aimed to explore the correlation of baseline, procedural, and postprocedure characteristics with the risk of rapid angiographic stenotic progression (RASP) and restenosis in coronary artery disease (CAD) patients after percutaneous coronary intervention (PCI) with drug‐eluting stents implantation.

Methods

Two hundred fourteen CAD patients underwent PCI with drug‐eluting stents implantation were consecutively enrolled. Baseline, procedural, and postprocedure characteristics of patients were collected for analysis. Coronary angiography was performed to evaluate coronary stenosis before PCI and at 12 months after PCI. RASP of nontarget lesions and restenosis of stent‐implanted target lesions were then assessed.

Results

37.8% CAD patients occurred RASP at 12 months after PCI and compared to non‐RASP group, RASP group presented with increased diabetes mellitus (DM) complication, higher concentration of serum uric acid (SUA), cardiac troponin I, N‐terminal probrain natriuretic peptide, and high sensitive C‐reactive protein (hs‐CRP) as well as elevated occurrence of multivessel artery lesions. In addition, DM, SUA, hs‐CRP, and multivessel artery lesions independently predicted high RASP risk. For restenosis, 21.0% patients occurred restenosis at 12 months after PCI, and patients in restenosis group presented with increased hypertension and DM occurrence, higher concentrations of SUA, LDL‐C, and hs‐CRP, as well as longer target lesion and length of stent in surgery compared to nonrestenosis group. Also, DM, SUA, LDL‐C, hs‐CRP, and length of target lesion independently predicted increased restenosis risk.

Conclusion

Diabetes mellitus, SUA, and hs‐CRP are potential predictive factors for increased risk of both RASP and restenosis in CAD patients underwent PCI and drug‐eluting stents implantation.
ALA‐mediated biphasic downregulation of α‐7nAchR/HIF‐1α along with mitochondrial stress modulation strategy in mammary gland chemoprevention
Authors: Roy Subhadeep , Singh Manjari , Sammi Shreesh Raj , Pandey Rakesh , Kaithwas Gaurav
Published: September 2018

The study elucidates the effect of ɑ‐linolenic acid (ALA) on mitochondrial stress, hypoxic cancer microenvironment, and intervention of cholinergic anti‐inflammatory pathway using N‐methyl‐N‐nitrosourea (MNU) induced estrogen receptor (ER+) mammary gland carcinoma and Caenorhabditis elegans model, respectively. The efficacy of ALA was scrutinized in vivo and in vitro using various experiments like hemodynamic studies, morphological analysis, antioxidants parameters, immunoblotting, and quantitative reverse transcription polymerase chain reaction. The effect of ALA was also validated using C. elegans worms. ALA administration had a positive effect on tissue architecture of the malignancy when scrutinized through the whole mount carmine staining, hematoxylin and eosin staining, and scanning electron microscopy. The proteomic and genomic checkpoint revealed the participation of mitochondrial dysfunction, alteration of hypoxic microenvironment, and involvement of cholinergic anti‐inflammatory response after treatment with ALA. ALA treatment has also increased the level of synaptic acetylcholine and acetylcholine esterase with a significant decrease in lipid content. It was concluded that ALA persuaded the mitochondrial stress, activation of downstream cholinergic anti‐inflammatory markers, and favorable regulation of hypoxia microenvironment through inhibition of fatty acid synthase and sterol regulatory element‐binding protein.
Studies on Synthesis of Novel Pyrido[2,3‐d] pyrimidine Derivatives and Their Anticancer Activity
Authors: Banda Veeraswamy , Gaddameedi Jitender Dev , Gautham Santhosh Kumar , Pillalamarri Sambasiva Rao , Chavva Kurumurthy , Rajesh Pamanji , Janapala Venkateswara Rao , Banda Narsaiah
Published: September 2018

A series of novel pyrido[2,3‐d]pyrimidine derivatives 7 were prepared starting from 2‐amino nicotinonitrile 3 via Grignard̛s reaction followed by cyclization and nucleophilic substitution. All the products 7 were screened against four human cancer cell lines. Compounds 7b, 7e, 7m, and 7o that showed good activity against all the cell lines have been identified.