bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protoporphyrin IX (PpIX)‐Coated Superparamagnetic Iron Oxide Nanoparticle (SPION) Nanoclusters for Magnetic Resonance Imaging and Photodynamic Therapy
Authors: Yan Lesan , Amirshaghaghi Ahmad , Huang Dennis , Miller Joann , Stein Joel M. , Busch Theresa M. , Cheng Zhiliang , Tsourkas Andrew 
Published: February 2018

AbstractThe ability to produce nanotherapeutics at large‐scale with high drug loading efficiency, high drug loading capacity, high stability, and high potency is critical for clinical translation. However, many nanoparticle‐based therapeutics under investigation suffer from complicated synthesis, poor reproducibility, low stability, and high cost. In this work, a simple method for preparing multifunctional nanoparticles is utilized that act as both a contrast agent for magnetic resonance imaging and a photosensitizer for photodynamic therapy for the treatment of cancer. In particular, the photosensitizer protoporphyrin IX (PpIX) is used to solubilize small nanoclusters of superparamagnetic iron oxide nanoparticles (SPIONs) without the use of any additional carrier materials. These nanoclusters are characterized with a high PpIX loading efficiency; a high loading capacity, stable behavior; high potency; and a synthetic approach that is amenable to large‐scale production. In vivo studies of photodynamic therapy (PDT) efficacy show that the PpIX‐coated SPION nanoclusters lead to a significant reduction in the growth rate of tumors in a syngeneic murine tumor model compared to both free PpIX and PpIX‐loaded poly(ethylene glycol)‐polycaprolactone micelles, even when injected at 1/8th the dose. These results suggest that the nanoclusters developed in this work can be a promising nanotherapeutic for clinical translation.
Nonenzymatic Dynamic Kinetic Resolution of in situ Generated Hemithioacetals: Access to 1,3‐Disubstituted Phthalans
Authors: Nath Utpal , Chowdhury Deepan , Pan Subhas Chandra 
Published: February 2018

AbstractThe first nonenzymatic DKR reaction of hemithioacetals is developed. Hemithioacetals were formed in situ via thiol addition and subsequently underwent an intramolecular oxa‐Michael reaction. The scope of the reaction was quite broad ranging from aliphatic to aromatic substituents and 1,3‐disubstituted‐1,3‐dihyroisobenzofuran products were obtained in good yields with moderate diastereoselectivities and high enantioselectivities.magnified image
Self‐Stabilized Hyaluronate Nanogel for Intracellular Codelivery of Doxorubicin and Cisplatin to Osteosarcoma
Authors: Zhang Yi , Wang Feng , Li Mingqiang , Yu Zhiqiang , Qi Ruogu , Ding Jianxun , Zhang Zhiyu , Chen Xuesi 
Published: February 2018

AbstractOsteosarcoma is one of the most serious bone malignancies with rapid speed of deterioration and low survival rate in children and teenagers. Chemotherapy is an important treatment for osteosarcoma, while the conventional small‐molecule therapeutics exhibit low efficacies and severe side effects in the clinic. Drug‐delivery platforms based on nanotechnology, particularly for self‐stabilized delivery platforms with prolonged blood circulation, enhanced intratumoral accumulation, improved antitumor efficacy, and diminished side effects, may break the deadlock on osteosarcoma chemotherapy. Here, a cisplatin (CDDP)‐crosslinked hyaluronic acid (HA) nanogel (CDDPHANG) is prepared for effective delivery of doxorubicin (DOX) to treat osteosarcoma. Importantly, both DOX and CDDP have led clinically used antitumor drugs, and CDDP acts as a crosslinker and ancillary anticarcinogen to prevent the premature release of DOX and to achieve synergistic therapeutic performance. Because of the enhanced stability of the nanogel, this CDDP‐crosslinked DOX‐loaded nanomedicine (CDDPHANG/DOX) exhibits an obviously prolonged circulation time compared to free drugs. Moreover, after valid tumor accumulation, DOX and CDDP are synergistically delivered into the tumor cells and synchronously released into the intracellular acidic environment. Based on the synergistic apoptosis‐inducing effects of DOX and CDDP, CDDPHANG/DOX reveals an evidently enhanced antitumor efficacy compared to free drugs and their combination, indicating its great prospects for the chemotherapy of osteosarcoma.
Small trees, big problems: Comparative leaf function under extreme edaphic stress
Authors: Cary Katharine L. , Pittermann Jarmila 
Published: February 2018

Premise of the StudyThe pygmy forest, a plant community of severely stunted conifers and ericaceous angiosperms, occurs on patches of highly acidic, nutrient‐poor soils along the coast of Northern California, USA. This system is an excellent opportunity to study the effect of severe nutrient deficiency on leaf physiology in a naturally‐occurring ecosystem. In this study, we seek to understand the physiological mechanisms stunting the plants' growth and their implications for whole plant function.MethodsWe measured 14 traits pertaining to leaf photosynthetic function or physical structure on seven species. Samples were taken from the pygmy forest community and from conspecifics growing on higher‐nutrient soils, where trees may grow over 30 m tall.Key ResultsPygmy plants of most species maintained similar area‐based photosynthetic and stomatal conductance rates to conspecific controls, but had lower specific leaf area (leaf area divided by dry weight), lower percent nitrogen, and less leaf area relative to xylem growth. Sequoia sempervirens, a species rare in the pygmy forest, had a categorically different response from the more common plants and had remarkably low photosynthetic rates.ConclusionsPygmy plants were not stunted by low photosynthetic rates on a leaf‐area basis; instead, several species had restricted whole‐plant photosynthesis due to low leaf area production. Pygmy plants of all species showed signs of greater carbon investment in their leaves and higher production of nonphotosynthetic leaf tissue, further contributing to slow growth rates.
Sleep in a comparative context: Investigating how human sleep differs from sleep in other primates
Authors: Nunn Charles L. , Samson David R. 
Published: February 2018

AbstractObjectivesPrimates vary in their sleep durations and, remarkably, humans sleep the least per 24‐hr period of the 30 primates that have been studied. Using phylogenetic methods that quantitatively situate human phenotypes within a broader primate comparative context, we investigated the evolution of human sleep architecture, focusing on: total sleep duration, rapid eye movement (REM) sleep duration, non‐rapid eye movement (NREM) sleep duration, and proportion of sleep in REM.Materials and MethodsWe used two different Bayesian methods: phylogenetic prediction based on phylogenetic generalized least squares and a multistate Onrstein‐Uhlenbeck (OU) evolutionary model of random drift and stabilizing selection.ResultsPhylogenetic prediction confirmed that humans sleep less than predicted for a primate of our body mass, predation risk, brain size, foraging needs, sexual selection, and diet. These analyses further revealed that humans pack an unexpectedly higher proportion of REM sleep within a shorter overall sleep duration, and do so by reducing NREM sleep (rather than increasing REM). The OU model generally confirmed these findings, with shifts along the human lineage inferred for TST, NREM, and proportion of REM, but not for REM.DiscussionWe propose that the risks and opportunity costs of sleep are responsible for shorter sleep durations in humans, with risks arising from terrestrial sleep involving threats from predators and conspecifics, and opportunity costs because time spent sleeping could be used for learning, creating material objects, and socializing.
Surface smoothing, decimation, and their effects on 3D biological specimens
Authors: Veneziano Alessio , Landi Federica , Profico Antonio 
Published: February 2018

AbstractObjectiveSmoothing and decimation filters are commonly used to restore the realistic appearance of virtual biological specimens, but they can cause a loss of topological information of unknown extent. In this study, we analyzed the effect of smoothing and decimation on a 3D mesh to highlight the consequences of an inappropriate use of these filters.Materials and methodsTopological noise was simulated on four anatomical regions of the virtual reconstruction of an orangutan cranium. Sequential levels of smoothing and decimation were applied, and their effects were analyzed on the overall topology of the 3D mesh and on linear and volumetric measurements.ResultsDifferent smoothing algorithms affected mesh topology and measurements differently, although the influence on the latter was generally low. Decimation always produced detrimental effects on both topology and measurements. The application of smoothing and decimation, both separate and combined, is capable of recovering topological information.ConclusionBased on the results, objective guidelines are provided to minimize information loss when using smoothing and decimation on 3D meshes.
Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations
Authors: Yong Robin , Ranjitkar Sarbin , Lekkas Dimitra , Halazonetis Demetrios , Evans Alistair , Brook Alan , Townsend Grant 
Published: February 2018

AbstractObjectivesThis study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics.Materials and MethodsSeventy dental casts from each group, equally subdivided by sex, were scanned using a structured‐light scanner. The 3D meshes of upper and lower premolars were processed using geometric morphometric methods. Seventy‐two landmarks were recorded for upper premolars and 50 landmarks for lower premolars. For each tooth type, two‐way ANOVA was used to assess group differences in centroid size. Shape variations were explored using principal component analysis and visualized using 3D morphing. Two‐way Procrustes ANOVA was applied to test group differences for ancestry and sex, and a “leave‐one‐out” discriminant function was applied to assess group assignment.ResultsCentroid size and shape did not display significant difference between the sexes. Centroid size was larger in Indigenous Australians for upper premolars and lower second premolars compared to the Australians of European ancestry. Significant shape variation was noted between the two ancestral groups for upper premolars and the lower first premolar. Correct group assignment of individual teeth to their ancestral groups ranged between 80.0 and 92.8% for upper premolars and 60.0 and 75.7% for lower premolars.DiscussionOur findings provide evidence of significant size and shape variation in human premolars between the two ancestral groups. High classification rates based on shape analysis of upper premolars highlight potential application of geometric morphometrics in anthropological, bioarcheological and forensic contexts.
A multivariate ecogeographic analysis of macaque craniodental variation
Authors: Grunstra Nicole D. S. , Mitteroecker Philipp , Foley Robert A. 
Published: February 2018

AbstractObjectivesTo infer the ecogeographic conditions that underlie the evolutionary diversification of macaques, we investigated the within‐ and between‐species relationships of craniodental dimensions, geography, and environment in extant macaque species. We studied evolutionary processes by contrasting macroevolutionary patterns, phylogeny, and within‐species associations.Materials and MethodsSixty‐three linear measurements of the permanent dentition and skull along with data about climate, ecology (environment), and spatial geography were collected for 711 specimens of 12 macaque species and analyzed by a multivariate approach. Phylogenetic two‐block partial least squares was used to identify patterns of covariance between craniodental and environmental variation. Phylogenetic reduced rank regression was employed to analyze spatial clines in morphological variation.ResultsBetween‐species associations consisted of two distinct multivariate patterns. The first represents overall craniodental size and is negatively associated with temperature and habitat, but positively with latitude. The second pattern shows an antero‐posterior tooth size contrast related to diet, rainfall, and habitat productivity. After controlling for phylogeny, however, the latter dimension was diminished. Within‐species analyses neither revealed significant association between morphology, environment, and geography, nor evidence of isolation by distance.DiscussionWe found evidence for environmental adaptation in macaque body and craniodental size, primarily driven by selection for thermoregulation. This pattern cannot be explained by the within‐species pattern, indicating an evolved genetic basis for the between‐species relationship. The dietary signal in relative tooth size, by contrast, can largely be explained by phylogeny. This cautions against adaptive interpretations of phenotype–environment associations when phylogeny is not explicitly modelled.
Morphological integration in the gorilla, chimpanzee, and human neck
Authors: Arlegi Mikel , Gómez‐Robles Aida , Gómez‐Olivencia Asier 
Published: February 2018

AbstractObjectivesAlthough integration studies are important to understand the evolution of organisms' traits across phylogenies, vertebral integration in primates is still largely unexplored. Here we describe and quantify patterns of morphological integration and modularity in the subaxial cervical vertebrae (C3–C7) in extant hominines incorporating the potential influence of size.Materials and MethodsThree‐dimensional landmarks were digitized on 546 subaxial cervical vertebrae from 141 adult individuals of Gorilla gorilla, Pan troglodytes, and Homo sapiens. Integration and modularity, and the influence of size effects, were quantified using geometric morphometric approaches.ResultsAll subaxial cervical vertebrae from the three species show a strong degree of integration. Gorillas show the highest degree of integration; conversely, humans have the lowest degree of integration. Analyses of allometric regression residuals show that size is an important factor promoting integration in gorillas, with lesser influence in chimpanzees and almost no effect in humans.DiscussionResults point to a likely ancestral pattern of integration in non‐human hominines, whereby the degree of integration decreases from cranial to caudal positions. Humans deviate from this pattern in the cranialmost (C3) and, to a lesser extent, in the caudalmost (C7) vertebrae, which are less integrated. These differences can be tentatively related to the emergence of bipedalism due to the presence of modern human‐like C3 in australopiths, which still preserve a more chimpanzee‐like C7.
Amyloid‐Polymorphie in der Energielandschaft der Faltung und Aggregation von Proteinen
Authors: Adamcik Jozef , Mezzenga Raffaele 
Published: February 2018

AbstractDie Proteinfaltung umfasst eine Vielzahl an Schritten und Konformationen, in denen das sich faltende Protein unterschiedliche thermodynamische Zustände erprobt, die durch lokale Minima gekennzeichnet sind. Kinetisch festgelegte Intermediate des An‐ oder Aus‐Wegs sind metastabile Faltungsintermediate auf dem Weg zu den niedrigsten absoluten Energieminima, die als nativ gefalteter Zustand konstatiert wurden, in dem intramolekulare Wechselwirkungen dominieren, und der Amyloid‐Zustand, in dem intermolekulare Wechselwirkungen dominieren. Diese Auffassung lässt allerdings die in Amyloid‐Spezies vorzufindende, reichhaltige Polymorphie unberücksichtigt. Dieser Kurzaufsatz gibt einen Überblick über die Energielandschaft der Proteinfaltung unter Berücksichtigung der neuesten Erkenntnisse bei der Identifikation spezieller Umwandlungen zwischen unterschiedlichen Amyloid‐Polymorphien. Die beobachteten Umwandlungen, wie “verdrillte Bänder→Kristalle” oder “helikale Bänder→Nanoröhren”, sowie verbotene Umwandlungen, wie “helikale Bänder↛Kristall”, werden diskutiert und innerhalb der Energielandschaft der Proteinfaltung und –aggregation positioniert. Abschließend werden Amyloid‐Kristalle als Grundzustand der Energielandschaft der Proteinfaltung und ‐aggregation identifiziert.
Synergistic Photoredox Catalysis and Organocatalysis for Inverse Hydroboration of Imines
Authors: Zhou Nengneng , Yuan Xiang‐Ai , Zhao Yue , Xie Jin , Zhu Chengjian 
Published: February 2018

AbstractThe first catalytic inverse hydroboration of imines with N‐heterocyclic carbene (NHC) boranes has been realized by means of cooperative organocatalysis and photocatalysis. This catalytic combination provides a promising platform for promoting NHC‐boryl radical chemistry under sustainable and radical‐initiator‐free conditions. The highly important functional‐group compatibility and possible application in late‐stage hydroborations represent an important step forward to an enhanced α‐amino organoboron library.
Coumarin Photocaging Groups Modified with an Electron‐Rich Styryl Moiety at the 3‐Position: Long‐Wavelength Excitation, Rapid Photolysis, and Photobleaching
Authors: Lin Qiuning , Yang Lipeng , Wang Zhiqiang , Hua Yujie , Zhang Dasheng , Bao Bingkun , Bao Chunyan , Gong Xueqing , Zhu Linyong 
Published: February 2018

AbstractA new class of coumarin photocaging groups modified with an electron‐rich styryl moiety at the 3‐position was constructed. The large π‐conjugated structure and stabilization of the carbocation intermediates by electron donors endowed the new photocaging groups with excellent long‐wavelength absorption, large two‐photon absorption cross‐sections, and high uncaging quantum yields. Moreover, the new photocaging groups displayed unique photobleaching properties after photocleavage as a result of the intramolecular cyclization rearrangement of a carbocation intermediate to form five‐membered ring byproducts and block the styryl conjugation at the 3‐position. These superior properties of the new photocaging groups are extremely beneficial for high‐concentration samples and thick specimens, thus extending the application of photocaging groups in many fields.
Synthesis of a Helical Bilayer Nanographene
Authors: Evans Paul J. , Ouyang Jiangkun , Favereau Ludovic , Crassous Jeanne , Fernández Israel , Perles Josefina , Martín Nazario 
Published: February 2018

AbstractA rigid, inherently chiral bilayer nanographene has been synthesized as both the racemate and enantioenriched M isomer (with 93 % ee) in three steps from established helicenes. This folded nanographene is composed of two hexa‐peri‐hexabenzocoronene layers fused to a [10]helicene, with an interlayer distance of 3.6 Å as determined by X‐ray crystallography. The rigidity of the helicene linker forces the layers to adopt a nearly aligned AA‐stacked conformation, rarely observed in few‐layer graphene. By combining the advantages of nanographenes and helicenes, we have constructed a bilayer system of 30 fused benzene rings that is also chiral, rigid, and remains soluble in common organic solvents. We present this as a molecular model system of bilayer graphene, with properties of interest in a variety of potential applications.
Co‐assembly of Polyoxometalates and Zwitterionic Amphiphiles into Supramolecular Hydrogels: From Crystalline Fibrillar to Amorphous Micellar Networks
Authors: Wu Aoli , Gao Xinpei , Sun Panpan , Lu Fei , Zheng Liqiang 
Published: February 2018

AbstractGelation mechanism is of utmost importance to the rational design of supramolecular hydrogelators. Although both kinetic and thermodynamic controlled self‐assembly processes have been widely studied in hydrogels, the formation relationship between crystalline and amorphous gel networks still remains ambiguous. Herein, a gelation transformation from a kinetic to a thermodynamic process was achieved by balancing the rigidity and flexibility of the inorganic–organic co‐assemblies. By using polyoxometalates and zwitterionic amphiphiles, the transition morphologies between crystalline and amorphous hydrogel networks were evidenced for the first time, as ordered wormlike micelles. Given the versatile applications of hydrogels in biological systems and materials science, these findings may highlight the potential of inorganic–organic binary supramolecular hydrogelators and fill in the blank between kinetic and thermodynamic controlled gelation processes.
Entropy‐Driven Diastereoselectivity Improvement in the Paternò–Büchi Reaction of 1‐Naphthyl Aryl Ethenes with a Chiral Cyanobenzoate through Remote Alkylation
Authors: Nagasaki Keisuke , Inoue Yoshihisa , Mori Tadashi 
Published: February 2018

AbstractThe precise stereocontrol of photocycloaddition reactions is still a significant challenge owing to their mechanistic complexity and the involvement of highly reactive and short‐lived intermediates. Attempts have hitherto been made through structural modifications, mostly by introducing steric conflicts, to increase the difference between the enthalpic barriers. Herein, we show that entropy plays a crucial role in influencing the diastereoselectivity of a Paternò–Büchi reaction. Remote meta alkylation of the donor caused nominal changes in its photophysical properties as well as those of the exciplexes derived thereof. Nevertheless, the diastereomeric excess of the oxetane product was greatly improved by about 40 %. This enhancement, which is not accompanied by any significant changes in the photophysical properties, is difficult to rationalize by conventional enthalpic control concepts based on repulsive steric and/or attractive intermolecular interactions as well as electronic perturbations. Differential activation parameters and compensatory enthalpy–entropy relationships revealed that the diastereoselectivity enhancement is not simply enthalpic but also entropic in origin.
Peroxidative catalytic oxidation of alcohols catalyzed by heterobinuclear vanadium(V) complexes using H2O2 as terminal oxidizing agents
Authors: Kurbah Sunshine D. , Asthana M. , Syiemlieh Ibanphylla , Lal Ram A. 
Published: February 2018

Here we report the catalytic oxidation of benzylic alcohol, hetero‐aryl alcohols and propargylic alcohols to their corresponding carbonyl compound using heterobimetallic sodium‐dioxidovanadium(V) complexes. The present catalytic oxidation studies proceed at 70 °C using H2O2 as terminal oxidant. During the whole process, the complexes react with hydrogen peroxide to form peroxo‐vanadium(V) species. The present study shows the heterogeneity of pre‐catalyst which could be easily recovered and moreover isolation of product is very simple.
Au(III) complexes loaded pH‐responsive magnetic nanogels for cancer therapy
Authors: Rezaei Seyed Jamal Tabatabaei , Norouzi Khadijeh , Hesami Ali , Malekzadeh Asemeh Mashhadi , Ramazani Ali , Amani Vahid , Ahmadi Roya 
Published: February 2018

A novel pH‐responsive magnetic nanogels were developed with the aim of targeted delivering and simultaneously releasing of newly synthesized Au(III)‐based anticancer drug, Au(1,7‐Phen)Br3. The obtained nanogels were characterized by FT‐IR, DLS, EDAX, TEM, XRD, ICP‐Ms and MRI. The TEM images showed that the nanogels had a spherical shape with a mean diameter of 20 nm. The in vitro release studies of Au (III)‐loaded nanogels showed a pH‐triggered controlled release of drugs. The in vitro cytotoxicity assay of samples to human cervical cancer HeLa cell lines indicated that the Au(III)‐loaded magnetic nanogels exert higher cytotoxicity in comparison with free Au(III) complex. Fluorescent microscope images indicated that these magnetic nanogels possessed notable cell specific targeting in vitro in the presence of an external magnetic field. The results show that this superparamagnetic nanocarrier is a promising candidate for inhibiting growth of tumor cells.