bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in chemical composition and nanostructure of SiC thin films prepared by PECVD during thermal annealing
Authors: Künle Matthias , Janz Stefan , Nickel Klaus Georg , Eibl Oliver 
Published: April 2011

AbstractSilicon carbide (SiC) thin films were deposited on silicon (Si) using plasma enhanced chemical vapor deposition (PECVD). Annealing was done in a rapid thermal annealing furnace at a temperature of 1300 °C. As‐deposited and annealed Si‐rich and stoichiometric SiC thin films were investigated by analytical transmission electron microscopy (AEM). TEM‐energy‐dispersive X‐ray spectroscopy was used to quantify the chemical composition of the SiC thin films with high accuracy. The chemical composition of the near stoichiometric SiC thin film changed during annealing from Si0.4C0.6 to Si0.5C0.5 due to diffusion of Si from the Si substrate into the film. The Si‐rich Si1–xCx film had the identical chemical composition of Si0.8C0.2 before and after annealing. As‐deposited films show nanoporosity within the bulk film. During annealing, v‐shaped defect structures were formed at the interface of the stoichiometric SiC thin film to the Si substrate. Diffraction patterns revealed that as‐deposited films were amorphous. During annealing the crystallization of 3C‐SiC occurred in near‐stoichiometric SiC thin films, whereas in Si‐rich Si1–xCx thin films two phases, namely Si and 3C‐SiC, crystallized. Low‐loss and core‐loss electron energy loss spectroscopy (EELS) verified the diffraction results. In the low‐loss spectra of the near stoichiometric SiC thin film, a plasmon peak located at 20.2 eV before and at 22.3 eV after annealing was detected. The low‐loss spectra of the Si‐rich Si1–xCx thin film showed an asymmetric plasmon peak with two maxima located at 18.5 and 25.0 eV in the as‐deposited film and 18.6 and 24.3 eV in the annealed Si‐rich Si1–xCx film. The 18.5 eV plasmon peaks is assigned to Si and the 25 eV plasmon peak is attributed to the SiC phase.
Advanced method for increasing the efficiency of white light quantum dot LEDs
Authors: Duty Chad E. , Bennett Charlee J. C. , Sabau Adrian S. , Jellison Gerald E. , Boudreaux Phillip R. , Walker Steven C. , Ott Ron 
Published: April 2011

AbstractCovering a light‐emitting diode (LED) with quantum dots (QDs) can produce a broad spectrum of white light. However, current techniques for applying QDs to LEDs suffer from a high density of defects and a non‐uniform distribution of QDs, which, respectively, diminish the efficiency and quality of emitted light. Oak Ridge National Laboratory (ORNL) has the unique capability to thermally anneal QD structures at extremely high power densities for very short durations. This process, called pulse thermal processing (PTP), reduces the number of point defects while maintaining the size and shape of the original QD nanostructure. Therefore, the efficiency of the QD wavelength conversion layer is improved without altering the emission spectrum defined by the size distribution of the QD nanoparticles. The current research uses a thermal model to predict annealing temperatures during PTP and demonstrates up to a 300% increase in photoluminescence for QDs on passive substrates.
First‐principles study on the effect of surface hydrogen coverage on the adsorption process of ammonia on InN(0001) surfaces
Authors: Suzuki Hikari , Togashi Rie , Murakami Hisashi , Kumagai Yoshinao , Koukitu Akinori 
Published: April 2011

AbstractTo examine the effect of hydrogen on the initial growth process of InN, the adsorption processes of group‐V sources commonly used in vapor phase epitaxy (VPE) were investigated using first‐principle calculations based on the density functional theory (DFT). The ideal and reconstructed surfaces with an adsorbed 0.75 monolayer of hydrogen were used as the initial surface structures to examine the influence of surface hydrogen coverage of InN(0001) surfaces on the adsorption processes of group‐V sources including NH3 and NH2 generated by the decomposition of NH3. From the calculations of the adsorption energies for each case, it was revealed that surface hydrogen coverage did not have an effect on the adsorption of NH3, whereas NH2 was significantly affected by the presence of hydrogen on the surface. In comparison with our previous results, it was also shown that the adsorption energies for NH3 and NH2 on InN(0001) surfaces are smaller than those on GaN and AlN(0001) surfaces (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient address space generation for an OPC UA server
Authors: Girbea Alina , Nechifor Septimiu , Sisak Francisc , Perniu Liviu 
Published: April 2011

SUMMARYThe new OPC Unified Architecture has been introduced as a replacement for the existing COM‐based specifications. The article describes a generalized algorithm for the automatic generation of the address space structure for an UA server. First, we present the general startup procedure of an OPC UA server, focusing on the address space generation step. Afterwards we introduce specialized algorithms for the generation of the type nodes, of object, variable, method and view nodes. Finally the additional references are added to the fully meshed address space. The basic ideas of the algorithms are: the splitting of the nodes into groups and the sequential addition of the groups to the address space, and the naming of a main reference for every target node. The algorithms have been applied for an aggregating UA server which models the devices of an assembly line. The main advantages are: shorter development time, easier maintenance and the possibility to add nodes to the address space in both online and offline mode. Copyright © 2011 John Wiley & Sons, Ltd.
Impact of nuchal translucency credentialing by the FMF, the NTQR or both on screening distributions and performance
Authors: Evans M. I. , Krantz D. A. , Hallahan T. W. , Sherwin J. 
Published: April 2011

AbstractObjectiveIn the USA, both The Fetal Medicine Foundation (FMF) and the Nuchal Translucency Quality Review Program (NTQR) have operated education, review and credentialing for physicians and sonographers for the measurement of nuchal translucency (NT). We sought to assess differences in the distribution of NT measurements based upon the system from which the operator obtained their education, review and credentialing.Methods398 311 NT measurements by 1541 sonographers who had performed ≥ 50 exams from July 2008 to June 2010 were grouped by organization. Differences between grouped measurements were assessed using analysis of variance of log10NT multiples of the median (MoM), with sonographer and organization as factors.ResultsMoM values were significantly lower (P⩽0.001) and SD was significantly higher (P < 0.001) for the NTQR group compared with the FMF group or those sonographers credentialed by both. The percentage of individuals with negative bias ≥ 10% was greater for the NTQR group (P < 0.001). The difference was less but still significant (P = 0.009) when bias was adjusted for by the overall median for the organization.ConclusionsAlthough NT MoM measurements were significantly lower and had a wider variance when obtained by the NTQR group, our data cannot distinguish between bias in training or the attributes of the participating sonographers in each program. With these large numbers, it is unlikely that patient characteristics could explain the discrepancy in distributions. Ongoing efforts to monitor sonographer performance with remediation for poor performers may reduce discrepancies between organizations. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
An asynchronous low‐power medium access control protocol for wireless sensor networks
Authors: Wang Heping , Zhang Xiaobo , Naït‐Abdesselam Farid , Khokhar Ashfaq 
Published: April 2011

ABSTRACTDuty cycling is a fundamental approach used in contention‐based medium access control (MAC) protocols for wireless sensor networks (WSNs) to reduce power consumption in sensor nodes. Existing duty cycle‐based MAC protocols use either scheduling or low‐power listening (LPL) to reduce unnecessary energy lost caused by idle listening and overhearing. This paper presents a new asynchronous duty‐cycled MAC protocol for WSN. It introduces a novel dual preamble sampling (DPS) approach to efficiently coordinate channel access among nodes. DPS combines LPL with a short‐strobed preamble approach to significantly reduce the idle‐listening issue in existing asynchronous protocols. We provide detailed analysis of the energy consumption by using well‐known energy models and compare our work with B‐MAC and X‐MAC, two most popular asynchronous duty cycle‐based MAC protocols for WSNs. We also present experimental results based on NS‐2 simulations. We show that depending on the traffic load and preamble length, the proposed MAC protocol improves energy consumption significantly without degrading network performances in terms of delivery ratio and latency. For example, for a traffic rate of 0.1 packets/s and a preamble length of 0.1 s, the average improvement in energy consumption is about 154%. Copyright © 2011 John Wiley & Sons, Ltd.
Stem cell genome‐to‐systems biology
Authors: Chia Na‐Yu , Ng Huck‐Hui 
Published: April 2011

AbstractStem cells are capable of extended proliferation and concomitantly differentiating into a plethora of specialized cell types that render them apropos for their usage as a form of regenerative medicine for cell replacement therapies. The molecular processes that underlie the ability for stem cells to self‐renew and differentiate have been intriguing, and elucidating the intricacies within the genome is pertinent to enhance our understanding of stem cells. Systems biology is emerging as a crucial field in the study of the sophisticated nature of stem cells, through the adoption of multidisciplinary approaches which couple high‐throughput experimental techniques with computational and mathematical analysis. This allows for the determination of the molecular constituents that govern stem cell characteristics and conjointly with functional validations via genetic perturbation and protein location binding analysis necessitate the construction of the complex transcriptional regulatory network. With the elucidation of protein–protein interaction, protein–DNA regulation, microRNA involvement as well as the epigenetic modifications, it is possible to comprehend the defining features of stem cells at the system level. WIREs Syst Biol Med 2012, 4:39–49. doi: 10.1002/wsbm.151This article is categorized under:

Developmental Biology > Stem Cell Biology and Regeneration
Polytypism of LiSr2Ge3 and the Solid Solutions LiSr2SixGe3–x and LiSr2–xEuxGe3 (0 < x < 1)
Authors: Xie Qinxing , Cuervo Reyes Eduardo , Wörle Michael , Nesper Reinhard 
Published: April 2011

AbstractThree modifications of LiSr2Ge3 were prepared by solid state syntheses at high temperatures under inert conditions in sealed niobium ampoules. α‐LiSr2Ge3 [space group Pnnm (No. 58), a = 11.102(1), b = 11.862(1), c = 4.631(1) Å, Z = 2] is isostructural to LiCa2Tt3 (Tt = Si, Ge), containing a one‐dimensional infinite germanium chain in (tttctc)n conformation. β‐LiSr2Ge3 [space group Fmmm (No. 69), a = 8.733(1), b = 8.996(1), c = 15.045(2) Å, Z = 4] crystallizes with the AgCa2Si3 structure. The β‐phase shows a tendency for lithium deficiency, which may be as small as 6 % but can be larger. γ‐LiSr2Ge3 [space group Fddd (No. 70), a = 8.675(3), b = 15.066(5), c = 18.258(5) Å, Z = 8] is isostructural to LiBa2Tt3. The latter two structures contain planar and distorted Ge6‐rings, respectively. Comparison of the structures reveals significant changes of lattice parameters and bond lengths. β‐LiSr2Ge3 may be stabilized by a slightly smaller lithium content due to preparation procedure. This assumption is supported by the structure analysis and total energy calculations. LiSr2Ge3 can be formulated as (Li+)2(Sr2+)4[Ge6]10– according to the Zintl–Klemm concept, with each of the Zintl anions having a partially occupied delocalized π* system. Theoretical investigations indicate metallic properties since π* bands are crossing the Fermi level. Phase widths were explored for Ge/Si and Sr/Eu exchange and complete miscibility was found for both series. Mixed silicide germanides exclusively crystallize in form of the γ‐phase, whereas the Eu‐containing mixed phases prefer the α‐form, both throughout the series.
Synthesis, Crystal Structure and Vibrational Spectra of Mg2[BN2]Br: A New Magnesium Nitridoborate Halide with Discrete [N–B–N]3– Groups
Authors: Kokal Ilkin , Somer Mehmet , Akselrud Lev , Höhn Peter , Carrillo‐Cabrera Wilder 
Published: April 2011

AbstractMg2[BN2]Br was prepared from stoichiometric mixtures of the respective binary components Mg3N2, MgBr2 and BN in sealed niobium ampoules placed in evacuated silica tubes at 1473 K. The monoclinic crystal structure (C2/c (no. 15); a = 9.1509(3) Å, b = 6.6209(3) Å, c = 6.4756(2) Å, β = 109.353(3)° and Z = 4) was determined from powder data. The crystal structure is characterized by cationic 32.4.3.4 nets of magnesium and anionic hexagonal closed packed 36 nets of six‐connected nodes occupied by [N–B–N]3– units and Br– anions. Both types of planar nets alternate along the [100] direction. The packing of such incoherent nets results in a monoclinic symmetry, which is a compromise for a structure built up from rod‐like [N–B–N]3– units and spherical bromine and magnesium atoms. Bond length and bond angle for the [N–B–N]3– unit are d(B–N) = 1.354(2) Å and ∠(N–B–N) = 177.1(9)°, respectively., Vibrational spectra were analyzed based on the D∞h symmetry of the relevant [N–B–N]3– moieties, considering the site symmetry splitting. The results are discussed in context with those of the known members of the magnesium dinitridoborate halide series, Mg2[BN2]Cl and Mg8[BN2]5I.
Bilateral Endoscopic Total Extraperitoneal (TEP) Inguinal Hernia Repair Does Not Induce Obstructive Azoospermia: Data of a Retrospective and Prospective Trial
Authors: Skawran S. , Weyhe D. , Schmitz B. , Belyaev O. , Bauer K. H. 
Published: April 2011

AbstractBackgroundThe endoscopic totally extraperitoneal (TEP) mesh repair is nowadays a well‐established tension‐free method for inguinal hernia repair. Mainly based on animal studies and case reports, a concern about the risk of postoperative infertility was expressed. This clinical study aimed to evaluate the risk of infertility due to obstructive azoospermia in men of fertile age who underwent a bilateral hernia repair.MethodsOver 3 years (2005–2008) 59 male patients, 18–60 years of age, underwent a bilateral TEP repair. Twenty‐one of them were prospectively (“light mesh”) and 38 retrospectively (“heavy mesh”) evaluated for testicular volume and perfusion, serum levels of sexual hormones, ejaculate volume, and number of spermatic cells. Those parameters were determined preoperatively (prospective group) and not earlier than 3 months postoperatively (both groups).ResultsNo significant difference between pre‐ and postoperative values was detected in the prospectively studied group. All postoperative parameters were within the normal range in the retrospective group. There was no evidence of impaired fertility in any patient due to the operation.ConclusionThe standardized TEP technique for simultaneous bilateral inguinal hernia repair in male patients was not associated with a higher risk for postoperative infertility after mesh implantation. The use of heavy‐weight meshes had no negative effect on fertility.
Surgical Capacity Building in Uganda Through Twinning, Technology, and Training Camps
Authors: Haglund Michael M. , Kiryabwire Joel , Parker Stephen , Zomorodi Ali , MacLeod David , Schroeder Rebecca , Muhumuza Michael , Merson Michael 
Published: April 2011

AbstractBackgroundNeurosurgical capacity is extremely deficient in East African countries where 27 neurosurgeons serve more than 250 million people. To build capacity, the Duke University Medical Center and New Mulago Hospital in Uganda applied a two‐pronged twinning approach that placed usable surplus equipment in a developing country’s National Hospital, combined with dedicated comprehensive surgical training camps.MethodsNeurosurgery, anesthesiology, nursing, and clinical engineering personnel supported three training camps. More than 21 tons of essential equipment was delivered to New Mulago Hospital in Uganda. Data was collected during the 2‐year period preceding and following the initiation of the program.ResultsDuring the 2 years after the program began, neurosurgery demonstrated a significant increase (180%) in the number and complexity of cases performed (p < 0.0001). Multiple cases performed in a single day increased eightfold (p < 0.0001), with utilization of elective operating room days improving from 43 to 98%. There was no change in the number of hospital admissions over the 4 years (p > 0.1), but there was a dramatic increase in the overall number of procedures performed by all surgical specialties (106%, p < 0.0001).ConclusionsThrough a twinning program combining delivery of surplus equipment and training camps, capacity building was accomplished and maintained. The program not only built overall surgical capacity, it improved the efficiency and increased the complexity of operative cases performed at the National Hospital in Uganda. This program could serve as a model for twinning, capacity building, and training in other developing countries where surgical disparities are among the greatest.
Quality of Care in Humanitarian Surgery
Authors: Chu Kathryn M. , Trelles Miguel , Ford Nathan P. 
Published: April 2011

AbstractHumanitarian surgical programs are set up de novo, within days or hours in emergency or disaster settings. In such circumstances, insuring quality of care is extremely challenging. Basic structural inputs such as a safe structure, electricity, clean water, a blood bank, sterilization equipment, a post‐anesthesia recovery unit, appropriate medications should be established. Currently, no specific credentials are needed for surgeons to operate in a humanitarian setting; the training of more humanitarian surgeons is desperately needed. Standard perioperative protocols for the humanitarian setting after common procedures such as Cesarean section, burn care, open fractures, and amputations and antibiotic prophylaxis, and post‐operative pain management must be developed. Outcome data, especially long‐term outcomes, are difficult to collect as patients often do not return for follow‐up and may be difficult to trace; standard databases for post‐operative infections and mortality rates should be established. Checklists have recently received significant attention as an instrument to support the improvement of surgical quality; knowing which items are most applicable to humanitarian settings remains unknown. In conclusion, the quality of surgical services in humanitarian settings must be regulated. Many other core medical activities of humanitarian organizations such as therapeutic feeding, mass vaccination, and the treatment of infectious diseases, such as tuberculosis and human immunodeficiency virus, are subject to rigorous reporting of quality indicators. There is no reason why surgery should be exempted from quality oversight. The surgical humanitarian community should pull together before the next disaster strikes.
Ultra‐minimally invasive local immune cell therapy and regenerative therapy by multi‐piercing surgery for abdominal solid tumor: therapeutic simulation by natural orifice translumenal endoscopic surgery‐assisted needlescopic surgery using 3‐mm diameter robots
Authors: Ohdaira Takeshi , Tsutsumi Norifumi , Xu Hao , Mori Megumu , Uemura Munenori , Ieiri Satoshi , Hashizume Makoto 
Published: April 2011

AbstractBackground/purposeWe have invented multi‐piercing surgery (MPS) which could potentially solve the triangular formation loss and device clashing which occur in single‐port surgery (SPS), as well as restricted visual field, organ damage by needle‐type instruments, and impaired removal of a resected organ from the body which occur in needlescopic surgery (NS). MPS is natural orifice translumenal endoscopic surgery (NOTES)‐assisted NS. We used 3‐mm diameter robots as needle‐type instruments for MPS to examine the possibility of local immune cell therapy and regenerative therapy using stem cells for pancreatic cancer.MethodsIn MPS using two robots, the therapeutic cell suspension was injected into a target region of pancreas in two pigs. Both retention of a capsule of liquid cell suspension and invasive level were evaluated.ResultsTriangular formation could be ensured. The use of small‐diameter robots allowed (1) the surgical separation of the pancreas and the retroperitoneum, and (2) the formation of the capsule containing the immune cell and stem cell suspension. The endoscope for NOTES provided a clear visual field and also assisted the removal of a resected organ from the body. The visual field of the endoscope could be oriented well by using an electromagnetic navigation system.ConclusionsMPS using small‐diameter robots could potentially solve the issues inherent in SPS and NS and could allow minimally invasive local immune cell and stem cell therapy.
da Vinci robotic single‐incision cholecystectomy and hepatectomy using single‐channel GelPort access
Authors: Sugimoto Maki , Tanaka Koichi , Matsuoka Yuichiro , Man‐i Mari , Morita Yoshinori , Tanaka Shinwa , Fujiwara Shoko , Azuma Takeshi 
Published: April 2011

AbstractBackground/purposeMinimally invasive surgery including laparoscopic and robotic surgery was recently approved for clinical use in hepatobiliary surgery. The purpose of this article is to evaluate the feasibility and technical aspects of robotic single incision for hepatobiliary surgery using the GelPort laparoscopic system in a preliminary animal study.MethodsWe performed eight robotic single‐incision laparoscopic surgery (SILS) procedures, including four cholecystectomies and four lateral segmentectomy of the liver, in a porcine study using the da Vinci S‐HD Surgical System. A single‐channel GelPort access was placed through a 2.5‐cm single incision for robotic access. A 12‐mm camera port, two 8‐mm ports for the robotic arms and one 5‐mm port for the patient‐side assistant were inserted. A Mini Loop Retractor was applied to retract the fundus of the gallbladder. The EndoWrist dissector and grasping forceps was introduced to fine‐dissect Calot's triangle. The instruments were crossed to avoid “sword fighting” and clashing of instruments in the abdomen. The cystic duct was divided after double ligation and the gallbladder was removed. Hepatic transection was performed with bipolar Harmonic shears and LigaSure for vascular pedicles.ResultsAll robotic SILS procedures were completed (8/8, 100%). The cholecystectomies and hepatectomies were safely performed in average operating times of 70 min (±15) and 60 min (±20), respectively, with minimal blood loss. There were no conversions, re‐interventions or extension of the skin incision.ConclusionsRobotic hepatobiliary SILS is technically feasible and safe using GelPort as a single‐incision access platform. Robotic SILS is becoming established and is enormously advantageous to the patient.