bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term Intracellular Recording of Optogenetically-induced Electrical Activities using Vertical Nanowire Multi Electrode Array
Authors: Yoo Jisoo , Kwak Hankyul , Kwon Juyoung , Ha Go Eun , Lee Elliot H. , Song Seungwoo , Na Jukwan , Lee Hyo-Jung , Lee Jaejun , Hwangbo Areum , Cha Eunkyung , Chae Youngcheol , Cheong Eunji , Choi Heon-Jin
Published: March 2020

Continuous recording of intracellular activities in single cells is required for deciphering rare, dynamic and heterogeneous cell responses, which are missed by population or brief single-cell recording. Even if the field of intracellular recording is constantly proceeding, several technical challenges are still remained to conquer this important approach. Here, we demonstrate long-term intracellular recording by combining a vertical nanowire multi electrode array (VNMEA) with optogenetic stimulation to minimally disrupt cell survival and functions during intracellular access and measurement. We synthesized small-diameter and high-aspect-ratio silicon nanowires to spontaneously penetrate into single cells, and used light to modulate the cell’s responsiveness. The light-induced intra- and extracellular activities of individual optogenetically-modified cells were measured simultaneously, and each cell showed distinctly different measurement characteristics according to the cell-electrode configuration. Intracellular recordings were achieved continuously and reliably without signal interference and attenuation over 24 hours. The integration of two controllable techniques, vertically grown nanowire electrodes and optogenetics, expands the strategies for discovering the mechanisms for crucial physiological and dynamic processes in various types of cells.
Low-frequency dual-frequency ultrasound-mediated microbubble cavitation for transdermal minoxidil delivery and hair growth enhancement
Authors: Liao Ai-Ho , Lin Keng-Hsien , Chuang Ho-Chiao , Tsai Chih-Hung , Lin Yi-Chun , Wang Chih-Hung , Shih Cheng-Ping , Liu Hao-Li
Published: March 2020

Ultrasound (US) has been found to rejuvenate and invigorate the hair follicles, increase the size of hair shafts, and promote new hair growth. Our present study found that dual-frequency US-mediated microbubble (MB) cavitation significantly enhanced minoxidil (Mx) delivery in both in vitro and in vivo models, while increasing the hair growth efficacy compared to single-frequency US sonication. The in vitro experiments showed that cavitation activity was enhanced more significantly during dual-frequency sonication than single-frequency sonication in higher concentration of MBs. The pigskin penetration depth in the group in which dual-frequency US was combined with MBs was 1.54 and 2.86 times greater than for single-frequency US combined with MBs and in the control group, respectively; the corresponding increases in the release rate of Mx at 18 hours in in vitro Franz-diffusion-cell experiments were 24.9% and 43.7%. During 21 days of treatment in C57BL/6J mice experiments, the growth rate at day 11 in the group in which dual-frequency US was combined with MBs increased by 2.07 times compared to single-frequency US combined with MBs. These results indicate that dual-frequency US-mediated MB cavitation can significantly increase both skin permeability and transdermal drug delivery. At the same US power density, hair growth was greater in the group with dual-frequency US plus MBs than in the group with single-frequency US plus MBs, without damaging the skin in mice.
A cotton pad-based sensor for the detection and determination of trihalomethanes in water by the colorimetric method
Authors: Fattahi Fariba , Shariati-Rad Masoud
Published: March 2020

Trihalomethanes in disinfected water samples can be detected and determined by a simple equipment.
Ultrafast room-temperature synthesis of hierarchically porous metal–organic frameworks with high space–time yields
Authors: Duan Chongxiong , Yu Yi , Li Feier , Wu Ying , Xi Hongxia
Published: March 2020

We developed a facile and general approach to rapidly synthesize four hierarchically porous MOFs (HKUST-1, ZIF-8, ZIF-61, and ZIF-90) under ambient conditions.
Realization of rocksalt Zn1−xCdxO thin films with an optical band gap above 3.0 eV by molecular beam epitaxy
Authors: Jang Hyo Chang , Saito Katsuhiko , Guo Qixin , Yu Kin Man , Walukiewicz Wladek , Tanaka Tooru
Published: March 2020

We have grown Zn1−xCdxO (ZnCdO) thin films by molecular beam epitaxy on α-Al2O3(0001) substrates across the full composition range of 0 ≤x≤ 1. A large optical gap of 3.0 eV is obtained in rocksalt-ZnCdO with a low resistivity and high mobility.
Influence of the type of carrier on ferromagnetism in a Si semiconductor implanted with Cu ions
Authors: Wang Li , Hou Denglu , Wu Chunfang , Shi Yuanping , Shi Shaohui , Gao Weikun , Feng Shunzhen , Liu Yingdi , Li Li , Ji Denghui
Published: March 2020

Possible exchange action mechanisms to explain the ferromagnetism origin. Here, the double exchange action hopped by spin-down electron as path ① and path ②. The super exchange action hopped by spin-up electron is shown as path ③.
Understanding the properties of dithienylethenes functionalized for supramolecular self-assembly: a molecular modeling study
Authors: Le Bras Laura , Berthin Roxanne , Hamdi Ismaïl , Louati Maroua , Aloïse Stéphane , Takeshita Michinori , Adamo Carlo , Perrier Aurélie
Published: March 2020

The behaviour of light-responsive supramolecular assemblies is rationalized with the help of molecular dynamics and TD-DFT calculations.
Bacterial community structure correlates with Legionella pneumophila colonization of New York City high rise building premises plumbing systems
Authors: Ma Xiao , Pierre David , Bibby Kyle , Stout Janet E.
Published: March 2020

Several bacterial taxa were found enriched in L. pneumophila culture positive water samples, demonstrating a potential association between Legionella colonization and the premises plumbing bacterial community.
The combination effect of vitamin K and vitamin D on human bone quality: a meta-analysis of randomized controlled trials
Authors: Kuang Xiaotong , Liu Chunxiao , Guo Xiaofei , Li Kelei , Deng Qingxue , Li Duo
Published: March 2020

Previous studies did not draw a consistent conclusion about the effects of vitamin K combined with vitamin D on human skeletal quality.
Microscopic investigations on the surface-state dependent moisture stability of a hybrid perovskite
Authors: Ma Jing-Yuan , Yan Hui-Juan , Li Ming-Hua , Sun Jian-Kun , Chen Yao-Xuan , Wang Dong , Hu Jin-Song
Published: March 2020

DMF post-annealing treatment can enlarge the grain size and reduce the surface defects, which prevent water from entering the grain, improving the stability of MAPbI3 films.
A CTAB-mediated antisolvent vapor route to shale-like Cs4PbBr6 microplates showing an eminent photoluminescence
Authors: Wei Yunwei , Zheng Wei , Shahid Malik Zeeshan , Jiang Zhixiang , Li Yuehua , Duan Zhongyao , Liu Guangning , Hu Xun , Li Cuncheng
Published: March 2020

Highly luminescent shale-like Cs4PbBr6 microplates with hundreds of microns in lateral dimension and formed by thin nanosheets with orientational stacking.
One-step synthesis of green emission carbon dots for selective and sensitive detection of nitrite ions and cellular imaging application
Authors: Zan Minghui , Li Cong , Liao Fei , Rao Lang , Meng Qian-Fang , Xie Wei , Chen Bei , Qie Xingwang , Li Li , Wang Liang , Dong Wen-Fei , Liu Wei
Published: March 2020

Schematic route of the carbon dots and their applications for the nitrite detection.
Actin and microtubule crosslinkers tune mobility and control co-localization in a composite cytoskeletal network
Authors: Farhadi Leila , Ricketts Shea N. , Rust Michael J. , Das Moumita , Robertson-Anderson Rae M. , Ross Jennifer L.
Published: March 2020

Microtubules (left) and actin filaments (right) show low mobility when in bundles because actin is swept up into static microtubule bundles.
Aggregation-induced phosphorescence enhancement in deep-red and near-infrared emissive iridium(iii) complexes for solution-processable OLEDs
Authors: Kim Hae Un , Jang Ho Jin , Choi Wanuk , Park Sungjin , Park Taiho , Lee Jun Yeob , Bejoymohandas K. S.
Published: March 2020

AIPE active deep-red and near infrared iridium(iii) complexes were developed using electron withdrawing substituents and effectively utilized them in solution processable PhOLEDs.
Ultrasensitive detection of nonlabelled bovine serum albumin using photothermal optical phase shift detection with UV excitation
Authors: Shimizu Hisashi , Takeda Shigenori , Mawatari Kazuma , Kitamori Takehiko
Published: March 2020

Ultrasensitive detection of nonlabelled bovine serum albumin is performed in micro/nanofluidic chips using a photothermal optical phase shift (POPS) detection system.
Transformation of a proton insulator to a conductor via reversible amorphous to crystalline structure transformation of MOFs
Authors: Song Yoodae , Khudozhitkov Alexander E. , Lee Jihyun , Kang Hyosik , Kolokolov Daniil I. , Stepanov Alexander G. , Yoon Minyoung
Published: March 2020

In this study, a successful proton conduction modulation of MOFs, from an ionic insulator to an ionic conductor, is demonstrated through their structural transformation.
The role of water and influence of hydrogen bonding on the self-assembly aggregation induced emission of an anthracene-guanidine-derivative
Authors: Pacheco-Liñán Pedro J. , Martín Cristina , Alonso-Moreno Carlos , Juan Alberto , Hermida-Merino Daniel , Garzón-Ruíz Andrés , Albaladejo José , Van der Auweraer Mark , Cohen Boiko , Bravo Iván
Published: March 2020

New AIEGen was obtained (QY = 1) based on the formation of an aggregate-dimer in the ground state assisted by water molecules. The inclusion of guanidine group is crucial to open a new framework for developing more environmentally friendly AIEGen.
Di-butyltin(iv) complexes with azo-carboxylates: synthesis, characterization, crystal structures and their anti-diabetic assay
Authors: Debnath Paresh , Singh Keisham Surjit , Singh Khaidem Kennedy , Sureshkumar Singh S. , Sieroń Lesław , Maniukiewicz Waldemar
Published: March 2020

The results of the anti-diabetic test of the compounds against the alpha glucosidase enzyme showed that2exhibits promising activity.
A coumarin based fluorescent chemodosimeter for phosgene gas detection instantaneously in solution and the gas phase
Authors: Paul Sima , Ghosh Pritam , Roy Partha
Published: March 2020

A coumarin based compound, 7-(diethylamino)-2-oxo-2H-chromene-3-carbaldehyde oxime, acts as a selective fluorescent chemodosimeter for phosgene gas in solution and as well as in the gas phase.
Pediatric glioblastoma target-specific efficient delivery of gemcitabine across the blood–brain barrier via carbon nitride dots
Authors: Liyanage Piumi Y. , Zhou Yiqun , Al-Youbi Abdulrahman O. , Bashammakh Abdulaziz S. , El-Shahawi Mohammad S. , Vanni Steven , Graham Regina M. , Leblanc Roger M.
Published: March 2020

A carbon nitride dot nanocarrier system with effective drug conjugation and selective target delivering to achieve enhanced drug efficacy on pediatric glioblastomas, while proving capability to penetrate blood–brain barrier.
Asymmetric total syntheses of naturally occurring α,β-enone-containing RALs, L-783290 and L-783277 through intramolecular base-mediated macrolactonization reaction
Authors: Chakraborty Joy , Ghosh Ankan , Nanda Samik
Published: March 2020

Asymmetric total synthesis of two naturally occurring α,β-enone containing RALs, L-783290 and L-783277 is described in this article.
Correction: Functionalization of triblock copolymer elastomers by cross-linking the end blocks via trans-N-alkylation-based exchangeable bonds
Authors: Hayashi Mikihiro , Chen Lei
Published: March 2020

Correction for ‘Functionalization of triblock copolymer elastomers by cross-linking the end blocks via trans-N-alkylation-based exchangeable bonds’ by Mikihiro Hayashi et al., Polym. Chem., 2020, DOI: 10.1039/c9py01759c.
Accelerated aging of fast pyrolysis bio-oil: a new method based on carbonyl titration
Authors: Black Stuart , Ferrell Jack R.
Published: March 2020

Fast pyrolysis bio-oils are known to age upon storage at room temperature, resulting in changes to both physical properties (increase in viscosity) and chemical composition (decrease in carbonyl content).
Degradation kinetics and mechanism of diclofenac by UV/peracetic acid
Authors: Zhang Li , Liu Yiqing , Fu Yongsheng
Published: March 2020

In this work, the degradation kinetics and mechanism of diclofenac (DCF) by UV/peracetic acid (PAA) was investigated.
Ultrafast synthesis of 2-(benzhydrylthio)benzo[d]oxazole, an antimalarial drug, via an unstable lithium thiolate intermediate in a capillary microreactor
Authors: Ramanjaneyulu Bandaru T. , Vidyacharan Shinde , Ahn Gwang-Noh , Kim Dong-Pyo
Published: March 2020

We present an ultrafast approach for the synthesis of 2-(benzhydrylthio)benzo[d]oxazole, an antimalarial drug, in 75% yield from benzo[d]oxazole-2-thiol and benzhydryl bromide via an unstable lithium thiolate intermediate in the presence of n-BuLi.
Controlled shape morphing of solvent free thermoresponsive soft actuators
Authors: Anju Vadakkumnalath Prakasan , Pratoori Raghunandan , Gupta Deepak Kumar , Joshi Rajendra , Annabattula Ratna Kumar , Ghosh Pijush
Published: March 2020

Reconfigurable actuators are designed based on chitosan and pNipam which has the capability to attain precise and programmable actuation. The current approach offers a feasible way to fabricate soft actuators with repeatable and reversible actuation.
Host–guest interaction-mediated fabrication of a hybrid microsphere-structured supramolecular hydrogel showing high mechanical strength
Authors: Zhang Xiongzhi , Liu Yuanxun , Wen Junwei , Zhao Zhiyong , Chen Hongxiang , Liu Xinghai , Liu Simin
Published: March 2020

The introduction of structured microsphere composites into hydrogels is found to improve their mechanical strength capability.
Ferroelectric and dielectric properties of Ca2+-doped and Ca2+–Ti4+co-doped K0.5Na0.5NbO3thin films
Authors: Gaukås Nikolai Helth , Glaum Julia , Einarsrud Mari-Ann , Grande Tor
Published: March 2020

Doped K0.5Na0.5NbO3films with good ferroelectric and dielectric properties were prepared by aqueous chemical solution deposition on platinized Si substrates.
Temperature-responsive conversion of thermally activated delayed fluorescence and room-temperature phosphorescence of carbon dots in silica
Authors: Sun Yuqiong , Liu Jinkun , Pang Xiaoliang , Zhang Xuejie , Zhuang Jianle , Zhang Haoran , Hu Chaofan , Zheng Mingtao , Lei Bingfu , Liu Yingliang
Published: March 2020

The unique temperature-responsive afterglow characteristics of CDs was reported for the first time, which can meet multiple potential applications in rapid fingerprint detection, temperature sensing, and advanced temperature-responsive anti-counterfeiting and encryption.
A ternary modular molecular co-assembly with flexibly tailored chiroptical properties
Authors: Liang Juncong , Zhang Nan , Hu Xiaoling , Hao Aiyou , Xing Pengyao
Published: March 2020

The modularized self-assembly protocol enables the fabrication of six chiroptical materials with fine-tailored polarized light absorption and emission properties.
Problems of field contamination when growing energy corn as monoculture
Authors: Korchak Mykola , Yermakov Serhii , Maisus Vasyl , Oleksiyko Serhiy , Pukas Vitaliy , Zavadskaya Iryna
Published: March 2020

Use of corn for energy purposes has high potential. To ensure the sustainable arrival of raw materials the possibility of using it as monoculture is important. To do it is necessary to quickly release the field from plant residues. The results of the study of the state and analysis of the nature of the field weediness by leaf-stem and root residues after harvesting corn are given taking into account the possibility of further use of the field for growing energetic corn.
The Utilization of Abandoned Petroleum Wells in Geothermal Energy Sector. Worldwide Trends and Experience
Authors: Chmielowska Anna , Tomaszewska Barbara , Sowiżdżał Anna
Published: March 2020

Since the oil crises in the 1970s, geothermal resources have received much attention and researches aimed at its recognition have been conducted all around the globe. Nevertheless, the investment cost associated mainly with drilling works is a crucial limitation for the successful implementation of new geothermal projects. The radical solution affecting the cost effectiveness of any geothermal investments might be an adaptation of existing un-exploited boreholes of the oil and gas sector for geothermal purposes. Moreover, a few studies on heat and/or energy recovery from oil and gas provinces have indicated that a tremendous amount of geothermal energy co-exists with petroleum fields. Thereby, the article centres on global concepts related to the adaptation of boreholes after the exploitation of hydrocarbon deposits or negative exploratory wells in order to exploit geothermal energy resources. Selected concepts focused on possible electricity production and the space heating sector are discussed. Other potential technologies based on utilization of geothermal energy attained by borehole heat exchangers are also indicated.
The concept of a passive heat transport system from solar collectors
Authors: Chludziński Daniel , Duda Michał , Sołowiej Piotr , Hałacz Joann , Lnage Andrzej
Published: March 2020

The paper presents a concept of building a passive heat transport system based on the use of an antigravity thermosyphon with a bubble pump. Such solutions are suggested when the heat source is located above the place of its reception, e.g. in the case of solar collector installations. One of the components of the system is the device forcing the circulation of the heating medium. In the presented system, this process is carried out without the use of additional external sources of energy, such as electricity, to supply the circulating pumps. Such an installation is autonomous, so the risk of failure is diminished. It is also possible to automatically adjust the system to changing operating conditions without the need for additional automation. Other known solutions of this type are not used due to their imperfection. The challenge is to select the right working medium, whose physical properties should on the one hand transmit as much heat as possible, and on the other hand enable the pumping of the heating medium to be performed with low energy consumption. In the opinion of the authors of the paper, it is possible to achieve with the use of two working media in one system: water and a substance with a low boiling point.
Influence of circulating pump efficiency on the heat exchange process in a plate heat exchanger used in a solar heating installation
Authors: Obstawski Paweł , Bakoń Tomasz , Kozikowska Anna
Published: March 2020

In solar heating systems with an absorber area of more than 20 m2, a plate heat exchanger is used as a separator between the primary glycol-based refrigerant and secondary water. The use of a plate heat exchanger enables an increase in the heat exchange area compared to the standard coil heat exchangers located inside the domestic hot water tank. An important problem is to determine the volume flow rate on both the primary and secondary side of the exchanger. The paper presents an analysis of the influence of the circulation pump efficiency on the primary and secondary side of the heat exchanger installed in a solar heating installation on the intensity of the heat exchange process.
Simulation of lymph flow with consideration of natural gravity force influence
Authors: Mozokhina Anastasiia , Lobov Gennadii
Published: March 2020

The model of lymph flow in the human lymphatic system in the quasi-one-dimensional approach is considered in the paper. Calculations with natural gravity force influence are presented. Calculations show that in some sets of parameters of lymphatic vessels the physiological flow can be reached in the model with zero global pressure gradient influence only by the “muscle” pump.
Nanostructured transition metal oxides obtained by SPVD
Authors: Plăiașu Adriana Gabriela , Ducu Marian Cătălin , Moga Sorin Georgian , Negrea Aurelian Denis , Modan Ecaterina Magdalena
Published: March 2020

The interest in the unique properties associated with materials having structures on a nanometer scale has been increasing at an exponential rate in last decade. Transition metal oxides are preferred materials for catalytic applications due to their half-filled d orbitals that make them exist in different oxidation states. Transition metal oxides show a broad structural variety due to their ability to form phases of varying metal to oxygen ratios reflecting multiple stable oxidation states of the metal ions. The Solar Physical Vapor Deposition (SPVD) presented in the paper as elaboration method is an original process to prepare nanopowders working under concentrated sunlight in 2 kW solar furnaces. The influence of the synthesis parameters on the chemical and microstructural characteristics of zinc and manganese oxides synthesized nanophases has been systematically studied using XRD, SEM and EDX.
Des greffes autologues aux cellules souches, quel avenir pour la chirurgie pré-implantaire ?
Authors: Ferre F.
Published: March 2020

La chirurgie pré-implantaire contemporaine néchappe pas au paradigme d’une médecine personnalisée, peu invasive, reproductible et pérenne. Ainsi, la prise en charge des défauts osseux des maxillaires connait une évolution transformant les concepts et la pratique au quotidien. Les greffes autologues ont longtemps constitué la technique de choix pour pallier les pertes de substances verticales et/ou horizontales, préalable indispensable à la pose d’implants. Depuis, lessor des substituts osseux allogéniques ou xenogéniques a permis de réduire le recours aux autogreffes dans un nombre croissant dindications. En effet, ces substituts osseux permettent de réduire la durée et la morbidité des interventions. Plus récemment, les progrès combinés de limagerie, de la CFAO et des techniques chirurgicales ont permis doptimiser les protocoles de ces greffes. Ainsi, la confection « sur-mesure » des greffons permet de réduire les manipulations de ces derniers et de diminuer le temps opératoire. Cependant, le faible potentiel biologique de ces substituts encourage à poursuivre les recherches dans ce domaine. Ainsi, lenrichissement des connaissances sur les cellules souches nourrit des espoirs importants en médecine régénératrice pour le traitement des défauts osseux. Toutes les étapes de la production : origine des cellules, méthodes de sélection et damplification, transfert in situ à l’aide de support, font lobjet de nombreuses recherches. Récemment, les premiers essais sur lhomme ont été mis en place afin d’évaluer leur efficacité et leur sécurité. Cette séance aura pour but de mettre en perspective ces nouvelles thérapeutiques dans le traitement des défauts osseux en chirurgie pré-implantaire.
Stratégie chirurgicale dans la gestion des défauts osseux sévères maxillaires et mandibulaires
Authors: Khoury G.
Published: March 2020

Les atrophies ou résorptions axiales des crêtes maxillaires ou mandibulaires, représentent une difficulté particulière dans les édentements de grandes étendues. La greffe autologue est une option qui, outre le besoin d’un site de prélèvement annexe, saccompagne d’un remodelage avec perte de volume, imposant une anticipation de la résorption, tant au temps de greffe que celui de la pose des implants. La préservation vasculaire du site opéré est un facteur clé de la sécurisation de lacte de greffe, mais pour autant il ninflue que peu sur ces résorptions secondaires. Les ostéotomies axiales, présentent sur un suivi à long terme, une stabilité volumétrique remarquable. Elles sont une alternative sérieuse aux greffes, avec bien entendu leurs propres indications et limites.
Chirurgie implantaire guidée : acquisition, planification, modélisation et production d'un guide chirurgical. Mise en place d'une chaine numérique pour la création interne et l'utilisation de guides chirurgicaux
Authors: Pajot T. , Ketoff S. , Bénichou L.
Published: March 2020

Introduction : Devenue incontournable de nos jours pour la réhabilitation de patients présentant des édentements unitaires, partiels ou totaux, la chirurgie implantaire a connu ces dernières années de nombreuses évolutions. Même si les mesures radiographiques et l'analyse des modèles d'étude physiques sont toujours les ressources les plus utilisées par les praticiens pour recueillir les différentes données nécessaires à la prise en charge du patient, la révolution numérique et l'avènement de l'impression en trois dimensions (3D) ont récemment beaucoup fait évoluer les pratiques et offrent de nouveaux horizons. C'est dans cet esprit qu'une chaine méthodologique complétement numérique a été mise en place pour la création de guides chirurgicaux implantaires à l'aide d'une imprimante 3D. OBSERVATION : L'auteur évoquera les différents éléments utilisés dans le service nécessaires à la mise en place de cette chaine digitale (Cone Beam, caméra d'empreintes optiques intra-orale, logiciel de planification, imprimante 3D) avant de présenter différents cas réalisés à l'aide de celle-ci.

DISCUSSION : L'utilisation d'une telle chaine dans un service hospitalier n'est pas simple et son impact difficile à évaluer. L'auteur reviendra donc dans un premier temps sur les différents problèmes rencontrés lors de la création des différents guides chirurgicaux (un point sera notamment fait sur la législation concernant l'utilisation de ces guides imprimés en 3D dans et par un établissement hospitalier). Dans un second temps, on évaluera également l'intérêt de se doter d'une telle chaine numérique : l'intérêt financier (pour l'hôpital mais aussi pour le patient), le temps imparti à la prise en charge du patient (nombre et durée des consultations, temps dédié à la planification implantaire), et l'intérêt chirurgical (notamment l'évaluation de la précision de la thérapeutique implantaire).

CONCLUSION : Les nouvelles technologies font évoluer nos pratiques. Si elles nécessitent initialement un investissement financier et humain important (temps d'adaptation, courbe d'apprentissage ), elles permettent à terme et utilisées dans de bonnes indications de faciliter et d'améliorer la prise en charge des patients.
Apport de la greffe gingivale épithélio conjonctive dans la reconstruction palpébrale
Authors: Landric C. , Alande C. , Ndiaye M.
Published: March 2020

La reconstruction palpébrale fonctionnelle et esthétique implique une réhabilitation de tous les plans palpébraux. Elle se base sur la distinction de deux entités fonctionnelles: la lamelle postérieure qui comporte le tarse, la conjonctive et les rétracteurs qui assurent l’abaissement de la paupière dans le regard vers le bas; la lamelle antérieure cutanéo- musculaire qui assure l’occlusion palpébrale. Toute technique doit impérativement restaurer les deux lamelles fonctionnelles. La réhabilitation du plan postérieur tarsoconjonctival peut utiliser différents greffons autologues: identiques (greffes et lambeaux tarsoconjonctival), soit analogues (greffes cartilagineuses, chondro muqueuses ou fibro muqueuses). Le recouvrement cutané dépend lui de la situation de la perte de substance et de la paupière concernée. L’utilisation de la fibromuqueuse palatine en chirurgie palpébrale fut décrite pour la première fois par Siegel en 1985. Histologiquement, le greffon palatin comporte trois couches de la superficie à la profondeur : la couche muqueuse, épithélium malpighien kératinisé, la couche glandulaire sous-muqueuse et le périoste. Cette technique à trouvée son application au centre hospitalier de Pau, dans la reconstruction de la paupière inférieure d’une patiente, après exérèse carcinologique d’un carcinome basocellulaire du bord libre. Egalement dans la reconstruction d’un plan tarso conjonctival chez un patient enophtalme pour permettre un soutien de la prothèse oculaire. Ces chirurgies sont réalisées en doubles équipes afin de mutualiser les compétences. La fibromuqueuse palatine trouve une indication de choix dans la reconstruction de tout ou partie de la lamelle postérieure de la paupière inférieure. Elle est indiquée en seconde intention pour la paupière supérieure car le taux de complications semble y être plus élevé (Leibovitch 2006). Il est nécessaire de prélever un greffon 10% plus large que la taille du défect muqueux car la greffe palatine se rétracte légèrement à moyen terme (Hatoko 1999). La fibromuqueuse palatine offre de nombreux avantages : une incurvation adéquate « moulant » le globe oculaire, une rigidité satisfaisante, une excellente survie en association à un lambeau et une morbidité acceptable au niveau du site donneur. Cohen et Shorr ont également montré que la muqueuse palatine subit une métaplasie en épithélium non kératinisé limitant ainsi à terme les risques d’irritation cornéenne et de kératite. Par opposition aux greffes tarso conjonctivales, l’intérêt majeur est la préservation de la paupière antagoniste. Les inconvénients sont surtout liés aux complications possibles: un saignement palatin souvent précoce dans les 48h postopératoires (10% des cas) (Wearne 2001); un retard de cicatrisation; une infection palpébrale à Candida; une sécrétion salivaire palpébrale due à la persistance de glandes salivaires dans le greffon et qui peut être tarie par cryothérapie.
Intérêts et techniques de greffe autogène pour la reconstruction de défauts osseux verticaux postérieurs mandibulaires
Authors: Raidot J. , Scheid F. , Sage P.O. , Offerle J.M. , Keller P.
Published: March 2020

La thérapeutique implantaire se présente aujourd'hui comme une solution de choix pour une réhabilitation prothétique esthétique et fonctionnelle. Cependant un volume osseux minimum est nécessaire. Dans le cas d'édentement mandibulaire postérieur, certains défauts osseux ne permettent pas la mise en place d'implants sans passer par une reconstruction du volume. Les greffes osseuses verticales dans le secteur posté rieur mandibulaire sont décrites comme une procé dure complexe. Différentes techniques aboutissant à l'augmentation du volume osseux sont décrites. Elles sont toutes constituées d'un coffrage, réalisé à partir de bloc autogène, d'une membrane résorbable ou non, avec ou sans armature en titane. Dans ce coffrage est disposé un comblement composé soit d'os particulé autogène, xénogène, ou d'un mélange d'os avec des biomatériaux. Les complications décrites sont variables en fonction de la technique utilisée. Le but de ce travail est de faire le point sur les différents avantages et inconvénients de ces techniques. Pour les comparer nous ferons une revue de la littérature. Nous mettrons ensuite en avant l'intérêt de l'utilisation de l'os autogène seul par l'étude d'une série de différents cas cliniques.
Ostéonécrose du prémaxillaire consécutive à une coagulation intravasculaire disséminée : à propos d’un cas
Authors: Mouraret A. , Gerard E. , Le Gall J. , Curien R.
Published: March 2020

La coagulation intravasculaire disséminée (CIVD) est une pathologie rare correspondant à l’activation systémique de la cascade de coagulation. Les thrombi fibrineux formés, auxquels s’ajoute un éventuel vasospasme, conduisent à l’ischémie et à la nécrose des tissus. La CIVD est fréquemment associée à un traumatisme, une blessure, une complication obstétrique ou à un choc septique. De nombreux cas d’ostéonécrose dus à une CIVD ont été décrits dans la littérature orthopédique (principalement concernant la tête fémorale), mais très peu de cas sont retrouvés concernant la région maxillo-mandibulaire. Une patiente de 83 ans se présente en consultation pour l’apparition récente de mobilités au niveau du bloc incisivo-canin maxillaire. L’interrogatoire révèle le diagnostic deux mois auparavant d’une leucémie myéloïde aigue, découverte de manière fortuite suite à un choc septique à E. Coli. Les bilans biologiques réalisés au moment du sepsis étaient en faveur d’une coagulation intravasculaire disséminée (CIVD). Quelques jours après, la patiente se plaignait de douleurs et de mobilités anormales localisées sur les dents antérieures maxillaires. Les examens cliniques et radiographiques (orthopantomogramme et cone beam) objectivent une nécrose osseuse du prémaxillaire limitée par les canines, avec un séquestre indépendant du reste du maxillaire. L’étude d’imputabilité conclut à la responsabilité de la CIVD en l’absence d’autres facteurs déclenchants et en raison d’une chronologie concordante. Le diagnostic de nécrose consécutive à une CIVD est alors posé. La prise en charge consiste en une séquestrotomie sous anesthésie générale et fermeture muqueuse. Un suivi régulier est mis en place avec une évolution favorable. Le prémaxillaire possède une vascularisation très riche assurée par les branches terminales de l’artère carotide externe, et par l’artère maxillaire. Les nécroses avasculaires sont par conséquent rares dans cette région. Cette vascularisation abondante explique le peu de cas décrits dans la littérature. On retrouve deux cas de nécrose consécutive à une CIVD au niveau de la mandibule et deux cas pour le prémaxillaire.
Histiocytose langerhansienne de l’adulte : à propos d’un cas
Authors: Oujdad S. , Zafad S. , El Attar H. , Ben Yahya I.
Published: March 2020

L’histiocytose langerhansienne est une maladie rare causée par la prolifération et l’infiltration d’un ou plusieurs organes, par des cellules dendritiques de type Langerhans. Elle s’exprime par des manifestations cliniques extrêmement polymorphes et peut toucher l’os, la peau, l’hypophyse, les poumons, le système nerveux central, et plus rarement le foie et le système digestif. Elle a été initialement décrite chez les enfants. L’histiocytose langerhansienne de l’adulte présente une entité particulière tant par ses manifestations cliniques que par sa prise en charge. Le cas présenté est celui d’un patient âgé de 53ans, en bon état de santé apparent et non fumeur, qui s’est présenté à la consultation pour des lésions nécrotiques et douloureuses des muqueuses gingivales mandibulaires et maxillaires, associées à des mobilités dentaires sévères. L’examen exobuccal ne révélait aucune asymétrie faciale ni adénopathies. L’examen endobuccal confirmait la présence de lésions nécrotiques gingivales et une parodontite sévère au niveau mandibulaire antérieur et maxillaire postérieur. Le secteur maxillaire antérieur présentait un parodonte sain. L’examen radiologique panoramique et Cone Beam CT , révélaient des lyses osseuses moyennes à terminales s’étendant de la 44 à la 38 et au niveau des molaires maxillaires droites et gauches. Les dents antérieures ne présentaient quant à elles pas de lyse. Par ailleurs des images lacunaires à l’emporte pièce siégeaient au niveau du secteur mandibulaire édenté. Ces manifestations évoquaient un lymphome ou une manifestation orale d’une infection virale type VIH. L’examen biologique révélait une légère hyperleucocytose et une augmentation de la vitesse de sédimentation à la première heure. L’examen anatomopathologique des lésions muqueuses, a rapporté la présence d’éléments histiocytaires se regroupant en nodules, concluant en une histiocytose langerhasienne de l’adulte. Le bilan d’extension ne révélait aucune atteinte associée, concluant en une histiocytose localisée. L’étude moléculaire a montré la présence d’une mutation V600E du gène BRAF (Facchetti et al, European journal of pathology, 471(4); 2017). Ce dernier est situé sur le chromosome 7, et il est impliqué dans l’envoi des signaux qui déterminent la croissance cellulaire. L’évolution et le pronostic de cette maladie sont étroitement liés à l’âge et aux organes atteints. Les régressions spontanées ont été rapportées, et peuvent être induites par un curetage ou par une simple biopsie. (Goncalves et al, Biomedical research notes,9(19); 2016) Pour notre cas, les extractions des dents mobiles avec curetage des lésions ont permis une cicatrisation complète. La thérapeutique médicamenteuse peut comprendre une corticothérapie locale ou systémique, des bisphosphonates, voire même une radiothérapie. Par ailleurs la confirmation de la mutation BRAF permet d’oser un traitement spécifique par inhibition de l’enzyme produite par ce gène. (Martıénez et al, Revisita Odontologica Mexicana, 16(2 ); 2012)
The genetic basis of facial skeletal characteristics and its relation with orthodontics
Authors: Cakan Derya Germec , Ulkur Feyza , Taner Tulin Uğur
Published: March 2020

Successful treatment of any orthodontic problem depends on an appropriate diagnosis of its etiology. It is well known that the genetics, as well as environmental factors, play an important role on the etiology of skeletal anomalies. Recent studies and advances in genetic sciences allowed the orthodontists to better understand the effects of genetics on the etiology of dentofacial characteristics and pathologies which in turn supported the effects of the genes in the development of dentofacial complex. In orthodontic practice, the genetic basis of a skeletal anomaly should also be considered during the diagnosis. Therefore orthodontic treatment plan should be chosen accordingly. However, further genetic studies are required to clearly determine all the specific genes leading to a particular skeletal variability caused by the polygenic nature of craniofacial traits. This article includes the current information on the association between orthodontics and genetics, an outline of the evidence based impact of heredity on dentofacial development as a review of the etiological factors of skeletal anomalies from the genetic point of view. (Eur J Dent 2012;6:340-345)
Work-Based Assessments in Higher General Surgical Training Program: A Mixed Methods Study Exploring Trainers' and Trainees' Views and Experiences
Authors: Aryal Kamal Raj , Currow Chelise , Downey Sarah , Praseedom Raaj , Seager Alexander
Published: March 2020

Introduction In the United Kingdom, work-based assessments (WBAs) including procedure-based assessments (PBAs), case-based discussions (CBDs), clinical evaluation exercises (CEXs), and direct observation of procedural skills (DOPS) have been used in Higher General Surgical Training Program (HGSTP) since the introduction of Modernising Medical Careers. Although the Intercollegiate Surgical Curriculum Project states that they should be used for the formative development of trainees using feedback and reflection, there is no study to look at the perception of their usefulness and barriers in using them, particularly in HGSTP. The aim of this study is to investigate trainer's and trainee's perception of their usefulness, barriers in using them, and way forward for their improvement in HGSTP.

Methods This was a mixed method study. In phase I, after ethics committee approval, an online survey was sent to 83 trainers and 104 trainees, with a response rate of 33 and 37%, respectively, using Online Surveys (formerly Bristol Online Survey) from July 2018 to December 2018. After analysis of this result, in phase II, semistructured interviews were conducted with five trainees and five trainers who had volunteered to take part from phase I. Thematic analysis was performed to develop overarching themes.

Results For professional formative development, 15% of the trainers and 53% of the trainees felt that WBAs had a low value. Among 4 WBAs—CEX, CBD, PBA, and DOPS—PBA was thought to be the most useful WBA by 52% trainers and 74% trainees.

More trainers than trainees felt that it was being used as a formative tool (33 vs. 16%). The total number of WBAs thought to be required was between 20 and 40 per year, with 46% of the trainers and 53% of the trainees preferring these numbers.

The thematic analysis generated four themes with subthemes in each: theme 1, “factors affecting usefulness,” including the mode of validation, trainer/trainee engagement, and time spent in validating; theme 2, “doubt on utility” due to doubt on validity and being used as a tick-box exercise; theme 3, “pitfalls/difficulties” due to lack of time to validate, late validation, e-mail rather than face-to-face validation, trainer and trainee behavior, variability in feedback given, and emphasis on number than quality; and theme 4, “improvement strategies.”

Conclusions The WBAs are not being used in a way they are supposed to be used. The perception of educational impact (Kirkpatrick levels 1 and 2) by trainers was more optimistic than by trainees. Improvements can be made by giving/finding more time, trainer training, more face-to-face validation, and better trainer trainee interactions.
Dielectric function of hybrid perovskites at finite temperature investigated by classical molecular dynamics
Authors: Mattoni A. , Caddeo C.
Published: March 2020

Ionic polarization and dielectric function play a fundamental role in the optoelectronic properties of hybrid perovskites, currently one of the most studied materials for next generation photovoltaics. The hybrid nature of the crystal, with molecular dipoles that can reorient within the inorganic lattice, gives rise to a complex dielectric response in the bulk material that has been largely studied and debated. Here, we investigate the nature and the relaxation properties of the dielectric polarization of hybrid perovskites at finite temperature by means of classical molecular dynamics. We provide evidence that a simple ionic model of classical interatomic forces is able to explain qualitatively the temperature and frequency dependence of the dielectric constant providing a picture that is fully consistent with experimental data. The constant dielectric function in the low-temperature phase is controlled by ionic displacements, while the temperature-dependent paraelectric behavior of the tetragonal phase is due to reorientation of dipoles that are responsible for the discontinuity at the orthorhombic-to-tetragonal transition. In the frequency domain, the molecular reorientations give rise to a broad band that is located in the 0.1 THz timescale at room temperature and that shifts down to the GHz timescale when cooling the system toward the tetragonal-to-orthorhombic phase transition. The relation between relaxation time and maximum absorption frequency is also clarified.
Electrical excitation and charge-state conversion of silicon vacancy color centers in single-crystal diamond membranes
Authors: Bray Kerem , Fedyanin Dmitry Yu. , Khramtsov Igor A. , Bilokur Maryna O. , Regan Blake , Toth Milos , Aharonovich Igor
Published: March 2020

The silicon-vacancy (SiV) color center in diamond has recently emerged as a promising qubit for quantum photonics. However, the electrical control and excitation of the SiV centers are challenging due to the low density of free carriers in doped diamond. Here, we realize electrical excitation of SiV centers in a single-crystal diamond membrane, which is promising for scalable photonic architectures. We further demonstrate electrical switching of the charge states of the SiV centers by applying a forward bias voltage to the fabricated diamond-membrane devices and identify the position of the SiV−/SiV0 charge transition level. Our findings provide a perspective toward electrical triggering of color centers in diamond and accelerate the development of scalable quantum nanophotonic technologies.
Global dynamics of Yang–Mills field and perfect-fluid Robertson–Walker cosmologies
Authors: Alho Artur , Bessa Vitor , Mena Filipe C.
Published: March 2020

We apply a new global dynamical system formulation to flat Robertson–Walker cosmologies with a massless and massive Yang–Mills field and a perfect-fluid with linear equation of state as the matter sources. This allows us to give proofs concerning the global dynamics of the models including asymptotic source-dominance toward the past and future time directions. For the pure massless Yang–Mills field, we also contextualize well-known explicit solutions in a global (compact) state space picture.
Onset and critical radius of heterogeneous bubble nucleation
Authors: Gupta Manish , Zou An , Maroo Shalabh C.
Published: March 2020

In this work, the onset of heterogeneous bubble nucleation is studied using molecular dynamics (MD) simulations and experiments. In MD simulations, heterogeneous bubble nucleation is initiated in liquid argon by partially heating a platinum surface. Multiple simulations are run by varying the width and temperature of the heated part of the surface; each simulation results in either a collapsing, stable or growing bubble for which Gibbs free energy is estimated and compared. These results atomistically confirm that a critical radius of nucleation exists for heterogeneous nucleation. Based on these simulations, an analytical model is developed to predict the critical width required for bubble nucleation at the nanoscale. Experiments are also conducted on the onset of bubble nucleation in water on a silicon-dioxide surface.
Epitaxial growth of rock salt MgZrN2 semiconductors on MgO and GaN
Authors: Bauers Sage R. , Mangum John , Harvey Steven P. , Perkins John D. , Gorman Brian , Zakutayev Andriy
Published: March 2020

Ternary nitride compound semiconductors have attracted recent attention as electronic materials since their properties can be tuned by cation stoichiometry and ordering. A recently discovered example is MgZrN2, a ternary analog to the rock salt semiconductor ScN. MgZrN2 has a larger bandgap and stronger dielectric response than the binary compound. Polycrystalline thin films of MgZrN2 have been studied, but demonstration of high-quality growth is still required to establish its suitability for technological applications. Here, we report on epitaxial growth of MgZrN2 thin films on (100) and (111) MgO substrates and (001) GaN templates. The MgZrN2 composition is confirmed by Rutherford backscattering spectrometry, showing no oxygen in the film except for a thin surface oxide layer. Epitaxial growth results in MgZrN2 with x-ray diffraction rocking curves with a full-width at half-maximum in the range of 0.3–3.0°, depending on the substrate. Transmission electron microscopy analysis of the MgZrN2 film grown on a (111) MgO substrate confirms epitaxial growth and shows a sharp film/substrate interface. In-plane temperature-dependent Hall effect measurements show that the material is an n-type semiconductor with a relatively high concentration (n300K ≈ 1019–1020 cm−3) of thermally activated electrons. Room-temperature transport measurements show a conductivity of 25 S cm−1 and a Seebeck coefficient of −80 μV K−1. Overall, these results provide an important step toward integration of rock salt MgZrN2 with other technological nitrides for device applications.
Liquid exfoliation of multilayer graphene in sheared solvents: A molecular dynamics investigation
Authors: Gravelle Simon , Kamal Catherine , Botto Lorenzo
Published: March 2020

Liquid-phase exfoliation, the use of a sheared liquid to delaminate graphite into few-layer graphene, is a promising technique for the large-scale production of graphene. However, the microscale and nanoscale fluid-structure processes controlling the exfoliation are not fully understood. Here, we perform non-equilibrium molecular dynamics simulations of a defect-free graphite nanoplatelet suspended in a shear flow and measure the critical shear rate γ̇c needed for the exfoliation to occur. We compare γ̇c for different solvents, including water and N-methyl-pyrrolidone, and nanoplatelets of different lengths. Using a theoretical model based on a balance between the work done by viscous shearing forces and the change in interfacial energies upon layer sliding, we are able to predict the critical shear rates γ̇c measured in simulations. We find that an accurate prediction of the exfoliation of short graphite nanoplatelets is possible only if both hydrodynamic slip and the fluid forces on the graphene edges are considered and if an accurate value of the solid–liquid surface energy is used. The commonly used “geometric-mean” approximation for the solid–liquid energy leads to grossly incorrect predictions.