bluuebunny/crossref_metadata_2025 huggingface dataset:
The Chemical Biology of Nitrogen
Authors: Walsh Christopher T
Published: May 2021

From DNA and RNA to proteins and vitamins the role of nitrogen is central in organismal metabolism. The Chemical Biology of Nitrogen comprehensively examines how the chemistry available to both inorganic and organic nitrogen compounds both enable and conditions the vast array of nitrogen biologies. This book provides a chemocentric approach to both the inorganic and organic chemical biology of nitrogen. Following an introduction to nitrogen trivalency the book progresses through the logic of inorganic nitrogen metabolism and organic nitrogen metabolites to nitrogen proteomics with an integrative approach to understanding the role of nitrogen in its many biologic roles. Authored by a renowned scientist and educator, this book is ideal for researchers in chemical biology and nitrogen metabolism and will be of particular interest to advanced students and postgraduates in biochemistry and chemical biology.
Interaction between sodium dodecylsulfate (SDS) and pluronic L61 in aqueous medium: assessment of the nature and morphology of the formed mixed aggregates by NMR, EPR, SANS and FF-TEM measurements
Authors: Prameela G. K. S. , Phani Kumar B. V. N. , Subramanian J. , Tsuchiya K. , Pan A. , Aswal V. K. , Abe M. , Mandal A. B. , Moulik S. P.
Published: May 2021

The gist of the morphological changes of the self-assemblies in solution by way of the SDS–L61 interaction primarily based on findings from SANS and FFTEM measurements supplemented with other methods.
Porous silsesquioxane cage and porphyrin nanocomposites: sensing and adsorption for heavy metals and anions
Authors: Majumdar Rakhi , Wannasiri Chidchanok , Sukwattanasinitt Mongkol , Ervithayasuporn Vuthichai
Published: May 2021

A porous silsesquioxane cage/porphyrin nanocomposite was designed as a dual fluorescent probe for the sensing and adsorption of both heavy metal ions and anions.
Electroanalytical performance of a β-cyclodextrin and ionic liquid modified carbon paste electrode for the determination of verapamil in urine and pharmaceutical formulation
Authors: Mutić Sanja , Radanović Danka , Vraneš Milan , Gadžurić Slobodan , Anojčić Jasmina
Published: May 2021

Sensitive and cost-effective verapamil sensor was prepared by modification of carbon paste electrode with ionic liquid and β-cyclodextrin and used for human urine and pharmaceutical samples analysis.
Selective demethylation of O-aryl glycosides by iridium-catalyzed hydrosilylation
Authors: Jones Caleb A. H. , Schley Nathan D.
Published: May 2021

O-Aryl glycosides serve as anomeric protecting groups in iridium- and borane-catalyzed hydrosilylative methyl ether cleavage. An iridium catalyst for selective 3-demethylation of carbohydrates has been developed.
Distinctly different reactivity of bis(silylenyl)-versus phosphanyl-silylenyl-substituted o-dicarborane towards O2, N2O and CO2
Authors: Xiong Yun , Yao Shenglai , Ruzicka Ales , Driess Matthias
Published: May 2021

While the reactions of carborane-based bis-silylene with O2, N2O, and CO2 yield the same Si2O2 containing product, activations of the latter with phosphanyl-silylenyl carborane affords different products featuring SiO, PO, or CO functionalities.
Constructing fused N-heterocycles from unprotected mesoionic N-heterocyclic olefins and organic azides via diazo transfer
Authors: Liang Qiuming , Hayashi Kasumi , Zeng Yimin , Jimenez-Santiago Jose L. , Song Datong
Published: May 2021

We report an unprecedented reactivity of unprotected mesoionic N-heterocyclic olefins toward organic azides to form fused pyrazole-triazole rings.
Theoretical investigation of polymorph- and coformer-dependent photoluminescence in molecular crystals
Authors: Feng Xibo , Becke Axel D. , Johnson Erin R.
Published: May 2021

A novel density-functional approach provides accurate predictions for the colour zoning of ROY polymorphs and the fluorescence energies of a family of 9-acetylanthracene cocrystals.
Evaluating the high-pressure structural response and crystal lattice interactions of the magnetically-bistable organic radical TTTA
Authors: Richardson Jonathan G. , Mizuno Asato , Shuku Yoshiaki , Awaga Kunio , Robertson Neil , Morrison Carole A. , Warren Mark R. , Allan David R. , Moggach Stephen A.
Published: May 2021

Paramagnetic suppression in TTTA at pressure is caused by a steady decrease in the separation between moieties containing the radical electron along π-stacking chains with no phase transition.
The symmetric C–D stretching spectator mode in the H + CHD3 → H2 + CD3 reaction and its effect on dynamical modeling
Authors: Zhao Bin
Published: May 2021

A new concept of a state-specific thermal flux operator is proposed and applied to the study of the symmetric C–D stretching spectator mode. This new concept provides an alternative and insightful venue for analysis of the transition state-control of reactions.
Formation of atmospheric molecular clusters from organic waste products and sulfuric acid molecules: a DFT study
Authors: Radola Bastien , Picaud Sylvain , Ortega Ismaël Kenneth , Ciuraru Raluca
Published: May 2021

DFT calculations show that skatole oxidation products may likely initiate the formation of nucleation precursors in the atmosphere.
Unraveling innate substrate-controlled arylation and bicyclization of 1,5-enynes with α,β conjugates: synthesis of substituted benzo[a]fluorenes
Authors: Gore Babasaheb Sopan , Lin Jun-Hao , Wang Jeh-Jeng
Published: May 2021

Herein, we describe a novel strategy for the aromatic C–H functionalization of electron-rich arenes with 1,5-enynes anchored by conjugates, catalyzed by a Brønsted acid under metal- and solvent-free conditions.
A more sustainable synthesis approach for cellulose acetate using the DBU/CO2 switchable solvent system
Authors: Wolfs Jonas , Meier Michael A. R.
Published: May 2021

Cellulose acetate was synthesized applying the DBU/CO2 switchable solvent system and a benign acetylating agent under mild conditions. High reagent conversion, a tunable degree of substitution and low cellulose backbone degradation were achieved.
Aerogels are not regulated as nanomaterials, but can be assessed by tiered testing and grouping strategies for nanomaterials
Authors: Keller Johannes G. , Wiemann Martin , Gröters Sibylle , Werle Kai , Vennemann Antje , Landsiedel Robert , Wohlleben Wendel
Published: May 2021

Aerogels may interact on multiple scales. Here we develop a testing strategy and potential categorization of 17 organic and 2 inorganic aerogels based on biosolubility, oxidative potential,in vitroreactivity andin vivoinstillation.
Molecular cluster route for the facile synthesis of a stable and active Pt nanoparticle catalyst
Authors: Fracchia Martina , Ghigna Paolo , Marelli Marcello , Scavini Marco , Vertova Alberto , Rondinini Sandra , Della Pergola Roberto , Minguzzi Alessandro
Published: May 2021

Molecular platinum clusters can be used for the synthesis of very small (ca.1.5 nm) Pt nanoparticles with enhanced catalytic activity and stability towards the oxygen reduction reaction. The Pt–C interactions were characterized by TEM and EXAFS.
Cyclophane with eclipsed pyrene units enables construction of spin interfaces with chemical accuracy
Authors: Metzelaars Marvin , Schleicher Sebastian , Hattori Takuma , Borca Bogdana , Matthes Frank , Sanz Sergio , Bürgler Daniel E. , Rawson Jeff , Schneider Claus M. , Kögerler Paul
Published: May 2021

A chemical strategy for the bottom-up construction of 3D spin interfaces is presented. Scanning tunnelling microscopy reveals distinct electronic features of a cyclophane with precisely designed pi-stacking on ferromagnetic Co(111) nanoislands.
Vibrational exciton delocalization precludes the use of infrared intensities as proxies for surfactant accumulation on aqueous surfaces
Authors: Carter-Fenk Kimberly A. , Carter-Fenk Kevin , Fiamingo Michelle E. , Allen Heather C. , Herbert John M.
Published: May 2021

Coupling between surfactant molecules at the air/water interface bleeds intensity into a diffuse background, such that single-wavelength vibrational intensity is effectively depleted at high surface coverage.
Route towards high-performance microfluidic fuel cells: a review
Authors: Zhou Yuan , Zhu Xun , Yang Yang , Ye Dingding , Chen Rong , Liao Qiang
Published: May 2021

Schematic illustration of parametric mapping in membrane-less microfluidic fuel cell (M-MFC) for performance improvement.
Magnetic flux structuring of the quiet Sun internetwork
Authors: Faurobert M. , Ricort G.
Published: May 2021

Context. The small-scale magnetism of the quiet Sun has been investigated by various means in recent decades. It is now well established that the quiet Sun contains in total more magnetic flux than active regions and represents an important reservoir of magnetic energy. But the nature and evolution of these fields remain largely unknown.

Aims. We investigate the solar-cycle and center-to-limb variations of magnetic-flux structures at small scales in internetwork regions of the quiet Sun.

Methods. We used Hinode SOT/SP data from the irradiance program between 2008 and 2016. Maps of the magnetic-flux density are derived from the center-of gravity method applied to the circular polarization profiles in the FeI 630.15 nm and FeI 630.25 nm lines. To correct the maps from the instrumental smearing of the telescope, we applied a deconvolution method based on a principal component analysis of the line profiles and on a Richardson-Lucy deconvolution of their coefficients. We took defocus effects and the diffraction of the SOT telescope into account. We then performed a spectral analysis of the spatial fluctuations of the magnetic-flux density in 10″ × 10″ internetwork regions spanning a wide range of latitudes from ±70° to the equator.

Results. At low and mid latitudes the power spectra normalized by the mean value of the unsigned flux in the regions do not vary significantly with the solar cycle. However at solar maximum for one scan in the activity belt showing an enhanced network, a marginal increase in the power of the magnetic fluctuations is observed at granular and larger scales in the internetwork. At high latitudes, we observe variations at granular and larger scales where the power decreases at solar maximum. At all the latitudes the power of the magnetic fluctuations at scales smaller than 0.5″ remains constant throughout the solar cycle.

Conclusions. At the equator the unsigned flux density is related to the vertical component of the magnetic field, whereas at high latitudes this flux density is mainly related to the horizontal component and probe higher altitudes. Our results favor a small-scale dynamo that operates in the internetwork, but they show that the global dynamo also contributes to the internetwork fields. At solar maximum the high-latitude horizontal internetwork fields seem to be depleted from the structures at granular and larger scales that are seen at solar minimum, whereas the internetwork within enhanced network regions show more structures at those scales than at solar minimum.
Wax deposition model of heavy oil in pipeline transportation
Authors: Chen Shiming , Chen Yan , Jiang Junze , Lou Bowen , Duan Jimiao
Published: May 2021

During the transportation process of heavy oil, wax deposition is prone to occur for the low temperature outside the tube and strong heat exchange, which will adversely affect the pipeline transportation of heavy oil. Based on the experimental data of the indoor deposition loop, this paper considered the impact of strong environmental heat transfer and oil flow shear on wax deposition and established a kinetic model of wax deposition for pipeline transportation of heavy oil. Numerical simulation was performed on the flow field and temperature field during the wax deposition process to obtain the model parameters. Through analyzing the deposition rate computed by the model, this paper reveals the effect of oil flow velocity, oil temperature and wall temperature difference on wax deposition.
Synthesis and application of new rhodamine 6G-derivative fluorescent probe molecules
Authors: Wang Chen , Wang Lei , Yu Liansheng , Ren Hengxin , Lv Yuguang
Published: May 2021

In the text, a new fluorescent probe based on rhodamine spirolactam ring was designed and synthesized. Rhodamine-like derivatives have not only good response speed and luminous performance, but also have a special switch type structure, which can specifically recognize responsive metal ions. In the paper, Rh-TEF, a 6G derivative of rhodamine, was synthesized by condensation reaction, the synthesized fluorescent probe was successfully used for solutions sample detection.
An investigation and analysis of working environment pollution in a lighter manufacturer
Authors: Wang Bi
Published: May 2021

In odder to control and eliminate environmental pollution at the source and protect the health of workers, the noise and air quality of the working environment of a lighter manufacturer were investigated, sampled and tested on site by using the national standard method. The results showed that the noise of 8h Leq value in ultrasonic welding post was 87.5dB (A), which exceeded the national occupational health standard. The noise for 8h Leq value, dust and liquefied petroleum gas content of the other post were lower than that of the national occupational health standard limits. Comprehensive and effective pollution control measures are put forward
Analysis of vegetation spatial distribution characteristics in Northwest China’s arid desert area
Authors: Wang Mingxin , Zhao Yiping
Published: May 2021

It is of great significance to study the characteristics of vegetation distribution in desert area for restoring vegetation, stabilizing ecosystem and ecological restoration in mining area. Taking the small watershed in Northwest China’s arid desert area where the typical open-pit coal mine is located as the study area, using GF-2 (Gaofen-2 satellite) images, calculating the NDVI (Normalized Difference Vegetation Index) results of the study area, extracting NDVI>0 as the vegetation cover area and combing with DEM (Digital Elevation Model), we analyse the relationship between vegetation distribution and slope aspect and water flow path. We conclude that in the natural state, the proportion of vegetation distribution on semi-sunny slope and shady slope in the study area is 74.8%, the proportion of sunny slope in the total area of the study area is 33.1%, and the proportion of vegetation distribution on this slope is only 11.9%, indicating that semi-sunny slope and shady slope are more suitable for growth in the study area. In the upper reaches of the basin, which is less affected by human activities, natural vegetation is distributed in strips along the flow path; In the mining area, which is obviously affected by human activities, the vegetation distribution characteristics change significantly with vegetation mainly distributed in the office area and being artificial greening.
Reclaimed water application to vegetation restoration in mining area: Determination of water quality standards and optimization of moderate treatment technology
Authors: Chen Le , Sun Kai , Zhang Panyue , Zhang Zhen , Liang Jinsong , Cai Yajing
Published: May 2021

Water shortage severely restricts vegetation restoration of mining area in the northwest China. Moderate treatment of reclaimed water is essential for improving the local ecological environment. In this study, relevant water quality standards issued by the states and research results were comprehensively considered to propose a reclaimed water quality standard suitable for vegetation restoration of mining area. The available domestic sewage and mine water was moderately treated by hybrid biological reactor system and nanofiltration membrane system, respectively. The effluent quality meet the requirement of reclaimed water quality standards in this study. This study provides theoretical support for vegetation restoration of mining area.
A comparative study of regional logistics competitiveness in Anhui province
Authors: Xu Jingyan , Zhang Qiqi
Published: May 2021

Based on the data of Anhui Province from 2009 to 2018, this paper analyzed the logistics competitiveness of Anhui Province, Northern Anhui, Central Anhui and Southern Anhui from three dimensions: basic support for logistics development, potential of logistics development and effectiveness of logistics development. In general, the logistics competitiveness of Anhui Province, Central Anhui, Northern Anhui and Southern Anhui from 2009 to 2018 has shown an upward trend year by year, with the three regions competing with one another. Among them, the basic support for logistics development has went from Central Anhui leading, to Northern Anhui, Southern Anhui being on a par with one another and having a balanced development; the effectiveness of logistics development in Northern Anhui has been developing particularly rapid and prominent; the potential of logistics development in three regions has shown little difference and the dynamic developing trend is similar. Suggestions are put forward: improving the policies and environment for logistics development, speeding up the construction of logistics information platform, attaching importance to the training and introduction of logistics talents.
Research and realization of automatic test system for motor controller unit
Authors: Zhao Lingxiao , Zeng Xiangpeng , Ma Huansheng
Published: May 2021

The development of electric vehicles has gradually become the mainstream trend of the automobile industry, and the motor controller unit is one of the key parts of the electric vehicle. The reliability and safety of the electric vehicle motor controller unit have attracted extensive attention in the industry in recent years. In order to meet the automotive industry on the motor controller unit reliability test verification. This paper studies and designs an automatic test system of the motor controller unit. And introduces the hardware and software control strategy test system in detail .The test results prove the feasibility and convenience of the test system.
Control Algorithm of Precision Machining
Authors: Chi Xiongfei
Published: May 2021

Due to more and more private customized non-standard design and precision manufacturing, as well as strict requirements for green environmental protection and sustainable economic development mode, it is challenging to realize the synchronous meeting of energy-saving optimization requirements in the processing process of high-precision workpiece. A new semi-automatic machining optimization system is proposed in this paper. The system is based on the high-precision 3D computer files of the workpiece to be processed and the laser thermophysical system. At the same time, the processing parameters are optimized based on the high-precision algorithm. The innovative contents of the high-precision optimization system include: (1) reciprocating fast high-frequency program design. Its single cycle task is: "core data acquisition, data in-depth analysis / machining precision refinement, key machining parameters recalibration", in order to maximize the process adaptability of the optimization system designed in this study in the highprecision machining process of different types of workpieces. (2) A new green energy-saving and environmental protection model, using primary chemical degreasing and laser derusting processing to get the most accurate 3D scanning files of parts waiting for processing, minimize the process error, so as to maximize the material and energy efficiency. In the calculation of the energy model, the most scientific consumption of coolant is considered.
Low-speed impact damage analysis of aviation composite material structure
Authors: He Jun , Cao Meng , Wang Zhishu , Cong Fanglin
Published: May 2021

Although the carbon fiber reinforced composite material has high specific strength and stiffness, design-versatility, anti-corrosion and other excellent features, but the impact resistance of composite structures is poor. Therefore, the composite laminates low-speed damage analysis has important significance. Based on a three-dimensional analysis theory of cumulative damage, using the commercial finite element analysis software ABAQUS to establish laminates subjected to low velocity impact finite element model. according to the numerical results and the consistency of the test results, shows that the used model of the article is reasonable and accurate, and the numerical simulation method is verified to be feasible. Finally, through the numerical simulation of process of laminated plates low speed impact damage, the damage characteristics and damage mechanism of the laminates at different times are analyzed, and the forming reasons and expanding rules of the main damage forms of fiber damage and matrix damage are revealed.
Simulation application of ALC external wall panel on rigid column frame brace system
Authors: Lv Xiujuan , Chen Wuxin , Li Xuguang
Published: May 2021

Taking a building under construction as an example, based on ABAQUS software, studies the failure mode, hysteretic curve, displacement ductility and energy consumption capacity of ALC external wall panel under three working conditions of assembled stiffened column frame brace system, assembled frame system and cast-in-place frame system.The simulation results show that:1.Under the action of low cycle load, the assembled stiffened column frame support system has no damage,the maximum stress value is 6.98 MPa, which is located at the position of steel plate at the column bottom; 2.Under the condition of ALC hanging wall plate, the structure ductility is better; 3.Part of the energy consumption is borne by the light material hanging wall plate, and the stiffened column frame support system has higher energy consumption capacity.The assembled ALC external wall panel based on the rigid column frame support system has better mechanical performance, can significantly improve the energy consumption capacity of the overall structure, and has high construction feasibility,economy and engineering application value.
Performance of ferritic steel 16MnDR using improved local fracture criterion
Authors: Pan Jianhua , Wang Yan , Guo Mingjie
Published: May 2021

Based on the finite element analysis and fracture toughness test data, this paper verifies the improved Ritchie-Knott-Rice (RKR) local failure criterion using 16MnDR ferritic steel for cryogenic pressure vessels. This criterion's applicability to 16MnDR was verified to verify fracture toughness's different influence factors in the ductile-to-brittle transition temperature (DBTT) region, such as specimen thickness (TST) and temperature. The results indicate that the (4δt, σ22c) criterion applies to 16MnDR steel and effectively transfers the minimum Jc value between samples of different temperatures and thickness.
Experimental research on latent heat characteristics of binary mixed molten salt
Authors: Wang Wei , Xiong Tao , Wu Yuting , Ma Chongfang
Published: May 2021

At present, thermal storage is considered as one of the key technologies to alleviate the problem of instability and intermittence for renewable energy. Due to relatively high latent heat, latent heat storage by molten salt is considered to a potential technology. Because of the restriction of different thermophysical parameters, the application of latent heat storage by molten salt has many technical obstacles. So, it is an urgent work to find a better mixed molten salt formula with comprehensive thermophysical properties. In this paper, we selected halogen salts (NaCl, NaF) and alkali (NaOH) to prepare binary mixed molten salts. From the results, for the mixed molten salt of NaCl-NaOH, NaCl:NaOH=1:9 has a maximum latent heat value of 301.2J/g. The initial melting temperature is about 200°C. With the increase of the mass ratio of NaCl, the termination melting temperature increases firstly then decreases. For mixed molten salt of NaF-NaOH, NaF:NaOH=1:9 has a maximum latent heat value of 199.5J/g, the initial and termination melting temperatures are about 265°C and 380°C, repectively. The latent heat value of NaCl-NaOH and NaF-NaOH mixed molten salts decreased with the increase of the mass ratio of halogen salts.
The management of displaced intracapsular femoral neck fractures at a Sub-Saharan Academic Hospital
Authors: Mukiibi Winifred , Maharaj Zia , Sekeitto Allan Roy , Mokete Lipalo , Pietrzak Jurek Rafal Tomasz
Published: May 2021

Background: Femoral neck fractures (FNFs) remain “the unsolved fracture” and optimal management is still controversial. The outcomes of hemiarthroplasty (HA) and total hip arthroplasty (THA) in the treatment of FNFs are inconsistent. As demand for management of FNFs continues to grow globally, evaluation of the appropriateness of treatment remains essential, particularly in resource-constrained settings. Methods: We conducted a retrospective chart review of all patients presenting with isolated low energy intracapsular FNFs to an orthopaedic academic unit in Sub-Saharan Africa from January 2016 to April 2019. The decision regarding HA or THA was largely based upon the Sernbo score and ASA classification. The majority of patients with a Sernbo score of ≥15 and ASA class III or better received THA. Results: There were 117 patients (33 male/84 female) 72 years (33–97 years) with FNFs who underwent 56 THA and 61 HA between January 2016 and April 2019. The mean Sernbo score was 15.99 overall (range 8–20) and was 18.95 (11–20) for THA patients compared to 14.46 (8–20) for HA patients (p = 0.042). Time taken from admission to the theatre was 8–19 days (1–22) and 7–61 days (2–31) for HA and THA respectively. The average length of stay (LOS) was 16.04 days and the main reason for same-day cancellations was the lack of post ICU/High Care beds. The 30-day mortality rates were 1.78% and 4.91% for THA and HA patients, respectively (p = 0.07). The mortality rate for patients with a Sernbo score < 15 was 15.38% overall, 8.93% for THA patients, and 21.31% for HA patients, respectively (p = 0.021). Conclusion: The 30-day mortality rate was comparable with published rates from developed countries. There were significant delays in time to theatre, high rates of same-day surgical cancellations, and increased LOS for both HA and THA. These factors play a cumulative role in inflating costs on a strained healthcare system in a developing country. A multidisciplinary approach including the care provision of a specialized geriatric unit is recommended.

Retrospective Study, Level III evidence
Der Nasen- oder Rachenabstrich in der COVID-19-Pandemie – Aspekte für den HNO-Arzt/die HNO-Ärztin – SARS-CoV-2, Coronavirus, Nasenabstrich, Rachenabstrich, Komplikationen
Authors: Deitmer Thomas , Dietz A. , Chaberny I. F. , Pietsch C.
Published: May 2021

Seit Beginn der SARS-CoV-2-Pandemie werden zunehmend Abstriche oder andere Beprobungen aus dem oberen Aerodigestivtrakt genommen, da hier vor allen Dingen in frühen Erkrankungsstadien hohe Viruslasten bestehen. Als diagnostische Möglichkeiten sind Abstriche aus der vorderen Nase, dem Nasopharynx oder dem Oropharynx sowie die Gewinnung von Rachenspülwasser oder Speichel möglich. Als Labormethoden stehen in einigen Minuten ablesbare Antigentests oder langwierigere RT-PCR-Methoden zur Verfügung. Abstriche werden von ärztlichem Personal, medizinischem Fachpersonal, Laien und im Eigentest, jeweils nach Instruktionen, durchgeführt. Auf die Aussagekraft und die Sensitivität des gesamten diagnostischen Prozesses haben somit viele dieser Faktoren einen Einfluss. Die PCR-Labormethode ist sensitiver als die Antigenmethode; der Abstrich aus dem Nasopharynx wird als der valideste Abstrichort angesehen. Eine korrekte Durchführung eines Tests kann auch bei nicht professionellen Personen mit guten Instruktionen erreicht werden. Komplikationen werden bei solchen Abstrichen, gemessen an der anzunehmenden Anzahl durchgeführter Prozeduren, sehr selten berichtet. Kurzfristiges Nasenbluten bei traumatischen Abstrichen ist anzunehmen, ohne dass darüber Publikationen aufgefunden werden konnten. Abgebrochene Abstrichträger mussten HNO-ärztlich entfernt werden. Verletzungen der Schädelbasis mit Liquorrhö wurden bisher sehr vereinzelt berichtet, davon 2-mal bei Anomalien wie Meningozelen. Die Wahl eines geeigneten diagnostischen Mediums hängt von vielen Parametern, wie Verfügbarkeit, zeitlicher Ablauf bis zum Ergebnis, Abstrich durch kundiges Personal oder Eigentest und etlichen anderen praktischen Erwägungen, ab.
Cyclotetrabenzil-Based Porous Organic Polymers with High Carbon Dioxide Affinity
Authors: Ashirov Timur , Alrayyani Maymounah , Song Kyung-Seob , Miljanić Ognjen Š. , Coskun Ali
Published: May 2021

Porous organic polymers (POPs) incorporating macrocyclic units have been investigated in recent years in an effort to transfer macrocycles' intrinsic host–guest properties onto the porous networks to achieve complex separations. In this regard, highly interesting building blocks are presented by the family of cyclotetrabenzoin macrocycles with rigid, well-defined, electron-deficient cavities. This macrocycle shows high affinity towards linear guest molecules such as carbon dioxide, thus offering an ideal building block for the synthesis of CO2-philic POPs. Herein, we report the synthesis of a POP through the condensation reaction between cyclotetrabenzil and 1,2,4,5-tetraaminobenzene under ionothermal conditions using the eutectic zinc chloride/sodium chloride/potassium chloride salt mixture at 250 °C. Notably, following the condensation reaction, the macrocycle favors three-dimensional (3D) growth rather than a two-dimensional one while retaining the cavity. The resulting polymer, named 3D-mPOP, showed a highly microporous structure with a BET surface area of 1142 m2 g−1 and a high carbon dioxide affinity with a binding enthalpy of 39 kJ mol−1. Moreover, 3D-mPOP showed very high selectivity for carbon dioxide in carbon dioxide/methane and carbon dioxide/nitrogen mixtures.
Prevalence of Anti-HBc Antibodies among HBsAg Negative Individuals and Its Association with Occult Hepatitis B
Authors: Madhavan Anitha , Sachu Arun , Balakrishnan Anu Kumar , Balakrishnan Sobha , Vasudevapanicker Jayalakshmi
Published: May 2021

Introduction Hepatitis B virus (HBV) infection is an endemic in many Asian countries, and among the major routes of transmission, transfusion is the one that should be prevented. Occult HBV infection (OBI) is defined as the presence of HBV DNA in the absence of detectable HBsAg, with or without anti-HBV antibodies. The aim of this study was to detect the prevalence of anti-HBc total antibodies among the HB surface antigen (HBsAg) negative individuals by way of enzyme-linked immunosorbent assay (ELISA), and detect the presence of HBV DNA among the anti-HBc seropositives by polymerase chain reaction (PCR). Anti-HBs among the HBV DNA positives were also found out by enzyme-linked fluorescent assay (ELFA).

Materials and Methods A total of 910 serum samples was subjected to initial screening for HBsAg by MERILISA HBsAg ELISA kits. The anti-HB core (HBc) total antibody titer was evaluated using MONOLISA ELISA (Biorad) kits. If found negative, the samples were discarded. If found positive, the samples underwent HBV DNA testing by nested PCR. Antibody to hepatitis B surface antigen (anti-HBs) was calculated among the DNA positives by ELFA.

Results A total of 133 samples were positive for anti-HBC total antibody, resulting in an overall prevalence of 14.6%. Overall prevalence of HBV DNA among the anti-HBc seropositives was 2.2%.

Conclusion Among the three HBV DNA positive patients, two belonged to the preoperative screening group, which is an alarming situation. Screening of blood for HBsAg has reduced the incidence of posttransfusion hepatitis, but HBV still remains the major source of transfusion transmitted infection in India.
Infective Endocarditis Caused by C. sordellii: The First Case Report from India
Authors: Chaudhry Rama , Bahadur Tej , Sagar Tanu , Agrawal Sonu Kumari , Arif Nazneen , Choudhary Shiv K. , Verma Nishant
Published: May 2021

Clostridium sordellii is a gram-positive anaerobic bacteria most commonly isolated from skin and soft tissue infection, penetrating injurious and intravenous drug abusers. The exotoxins produced by the bacteria are associated with toxic shock syndrome. We report here a first case of infective endocarditis due to C. sordellii from a female patient with ventricular septal defect from India.
Infectious Myelopathies
Authors: Anand Pria
Published: May 2021

In the setting of both globalization and increasing use of immunosuppressive therapy, infectious myelopathies are an important cause of morbidity worldwide. Clinical spinal cord syndromes related to infection are varied, including transverse myelitis, acute flaccid paralysis related to anterior horn cell involvement, spinal cord compression, chronic spastic paraparesis, and myeloradiculitis. Causative pathogens include viruses, parasites, pyogenic and atypical bacteria, and fungi. The epidemiology, clinical characteristics, diagnosis, and treatment of selected organisms will be discussed in this article.
Metabolic and Toxic Myelopathies
Authors: Slama Michaël C. C. , Berkowitz Aaron L.
Published: May 2021

Metabolic and toxic causes of myelopathy form a heterogeneous group of disorders. In this review, we discuss the causes of metabolic and toxic myelopathies with respect to clinical presentation, pathophysiology, diagnostic testing, treatment, and prognosis. This review is organized by temporal course (hyperacute, acute, subacute, and chronic) and etiology (e.g., nutritional deficiency, toxic exposure). Broadly, the myelopathies associated with dietary toxins (neurolathyrism, konzo) and decompression sickness present suddenly (hyperacute). The myelopathies associated with heroin use and electrical injury present over hours to days (acutely). Most nutritional deficiencies (cobalamin, folate, copper) and toxic substances (nitrous oxide, zinc, organophosphates, clioquinol) cause a myelopathy of subacute onset. Vitamin E deficiency and hepatic myelopathy cause a chronic myelopathy. Radiation- and intrathecal chemotherapy-induced myelopathy can cause a transient and/or a progressive syndrome. For many metabolic and toxic causes of myelopathy, clinical deficits may stabilize or improve with rapid identification and treatment. Familiarity with these disorders is therefore essential.
Analytical electron microscopy of (2¯01) β-Ga2O3/SiO2 and (2¯01) β-Ga2O3/Al2O3 interface structures in MOS capacitors
Authors: Klingshirn Christopher J. , Jayawardena Asanka , Dhar Sarit , Ramamurthy Rahul P. , Morisette Dallas , Zheleva Tsvetanka , Lelis Aivars , Salamanca-Riba Lourdes G.
Published: May 2021

Chemical and structural features of (2¯01) β-Ga2O3 interfaces with SiO2 and Al2O3 gate oxides formed by low pressure chemical vapor deposition (SiO2) and atomic layer deposition (Al2O3) were investigated by analytical electron microscopy in order to identify features that may explain electrical properties recently observed in the same samples. Cross-sectional transmission electron microscopy at the Ga2O3/SiO2 interface revealed nanoscale interfacial roughness increasing with higher post-deposition annealing temperature. At the Ga2O3/Al2O3 interface, a few nanometers of epitaxial Al2O3 was seen prior to the complete crystallization of the gate oxide film after tens of seconds exposure to the electron beam. Multivariate statistical analysis of electron energy loss spectroscopy signals showed evidence of interdiffusion between Al and Ga into the substrate and gate oxide, respectively, which was more pronounced following post-deposition annealing at elevated temperatures. The interdiffusion provides an explanation for the increased interface trap density previously reported in these devices. These results identify issues with the processing methods of the gate oxide affecting the performance and reliability of β-Ga2O3 metal–oxide–semiconductor devices.
Synchronization in populations of electrochemical bursting oscillators with chaotic slow dynamics
Authors: Magrini Luciano A. , Oliveira Domingues Margarete , Macau Elbert E. N. , Kiss István Z.
Published: May 2021

We investigate the synchronization of coupled electrochemical bursting oscillators using the electrodissolution of iron in sulfuric acid. The dynamics of a single oscillator consisted of slow chaotic oscillations interrupted by a burst of fast spiking, generating a multiple time-scale dynamical system. A wavelet analysis first decomposed the time series data from each oscillator into a fast and a slow component, and the corresponding phases were also obtained. The phase synchronization of the fast and slow dynamics was analyzed as a function of electrical coupling imposed by an external coupling resistance. For two oscillators, a progressive transition was observed: With increasing coupling strength, first, the fast bursting intervals overlapped, which was followed by synchronization of the fast spiking, and finally, the slow chaotic oscillations synchronized. With a population of globally coupled 25 oscillators, the coupling eliminated the fast dynamics, and only the synchronization of the slow dynamics can be observed. The results demonstrated the complexities of synchronization with bursting oscillations that could be useful in other systems with multiple time-scale dynamics, in particular, in neuronal networks.
Real-time control of dendritic propagation in rechargeable batteries using adaptive pulse relaxation
Authors: Aryanfar Asghar , Ghamlouche Yara , Goddard William A.
Published: May 2021

The non-uniform growth of microstructures in dendritic form inside the battery during prolonged charge–discharge cycles causes short-circuit as well as capacity fade. We develop a feedback control framework for the real-time minimization of such microstructures. Due to the accelerating nature of the branched evolution, we focus on the early stages of growth, identify the critical ramified peaks, and compute the effective time for the dissipation of ions from the vicinity of those branching fingers. The control parameter is a function of the maximum interface curvature (i.e., minimum radius) where the rate of runaway is the highest. The minimization of the total charging time is performed for generating the most packed microstructures, which correlate closely with those of considerably higher charging periods, consisting of constant and uniform square waves. The developed framework could be utilized as a smart charging protocol for safe and sustainable operation of rechargeable batteries, where the branching of the microstructures could be correlated with the sudden variation in the current/voltage.
On Kirillov’s lemma and the Benson–Ratcliff invariant
Authors: Dali Béchir , Khalfi Rafik
Published: May 2021

In this paper, we study the conjecture of Benson and Ratcliff, which deals with the class of nilpotent Lie algebras of a one-dimensional center. We show that this conjecture is true for any nilpotent Lie algebra g with dimg≤5, but it fails for the dimensions greater or equal to 6. To this end, we produce counter-examples to the Benson–Ratcliff conjecture in all dimensions n ≥ 6. Finally, we show that this conjecture is true for the class of three-step nilpotent Lie algebras and for some other classes of nilpotent Lie algebras.
Perspective on mode-division multiplexing
Authors: Su Yikai , He Yu , Chen Haoshuo , Li Xiaoying , Li Guifang
Published: May 2021

We review the current status of mode-division multiplexing (MDM) techniques in fibers and on chips. Three system applications are introduced, including quasi-single mode transmission, multicore few-mode amplifier, and fiber sensing. We also discuss the technology development trend in terms of multiple-input-multiple-output-free MDM, economics of MDM, and quantum information processing. Finally, we provide perspectives on emerging applications beyond communications by leveraging the optical properties of high order modes, e.g., nonlinear optics in the visible regime, broadband frequency comb generation, and super resolution endoscopy.
Quint points lattice in a driven Belousov–Zhabotinsky reaction model
Authors: Field Richard J. , Freire Joana G. , Gallas Jason A. C.
Published: May 2021

We report the discovery of a regular lattice of exceptional quint points in a periodically driven oscillator, namely, in the frequency–amplitude control parameter space of a photochemically periodically perturbed ruthenium-catalyzed Belousov–Zhabotinsky reaction model. Quint points are singular boundary points where five distinct stable oscillatory phases coalesce. While spikes of the activator show a smooth and continuous variation, the spikes of the inhibitor show an intricate but regular branching into a myriad of stable phases that have fivefold contact points. Such boundary points form a wide parameter lattice as a function of the frequency and amplitude of light absorption. These findings revise current knowledge about the topology of the control parameter space of a celebrated prototypical example of an oscillating chemical reaction.
Programmable system on chip for controlling an atomic physics experiment
Authors: Sitaram A. , Campbell G. K. , Restelli A.
Published: May 2021

Most atomic physics experiments are controlled by a digital pattern generator used to synchronize all equipment by providing triggers and clocks. Recently, the availability of well-documented open-source development tools has lifted the barriers to using programmable systems on chip (PSoCs), making them a convenient and versatile tool for synthesizing digital patterns. Here, we take advantage of these advancements in the design of a versatile clock and pattern generator using a PSoC. We present our design with the intent of highlighting the new possibilities that PSoCs have to offer in terms of flexibility. We provide a robust hardware carrier and basic firmware implementation that can be expanded and modified for other uses.
Permanent magnet bottom-stirred swirling flow in coaxial shallow cylindrical containers
Authors: Berenis D. , Baranovskis R. , Grants I. , Beinerts T. , Bojarevičs A.
Published: May 2021

Here, an original rotating permanent magnet (RPM) system placed coaxially with the liquid metal container is studied as an effective means of generating flow in shallow cylinders for potential application in aluminum metallurgy (e.g., for ladle stirring and metal dosing). The studied RPM system generates volume force with strong axial variation and force maximum near the radial midpoint. The numerical and experimental data show that, in the shallow cylinder case, the azimuthal velocity follows the force radial distribution. The resulting velocity maximum occurs near the radial midpoint, unlike in the traditional rotating magnetic field (RMF) stirrer systems, where the velocity maximum occurs near the outer radius. An analytical description is developed to explain the velocity radial distribution. The numerically calculated velocity distribution shows a peculiar result that the bottom-stirred liquid metal container results in peak angular momentum at the top of the container. The solution to asymptotic boundary layer equations shows that this is due to the force axial variation.
Experimental evidence for non-purely electric field-induced threshold switching and modified thermal-assisted model in GeTe phase change material
Authors: Chen Ziqi , Tong Hao , Li Xin , Wang Lun , Zhao Ruizhe , Gu Wei , Miao Xiangshui
Published: May 2021

In this paper, we present a multiple layer device for investigating the impact of electric field on the conductance switching of GeTe phase change material excluding the contribution from Joule heat. The device includes a dielectric layer with excellent current-blocking which can result in a large electric field generated in the amorphous GeTe film and almost no current. With the generated electric field far beyond its threshold value for the conductance switching, our experimental data indicate that the conductance switching has not happened in the GeTe film. This indicates that the ovonic threshold switching (OTS) could not be induced by the purely electric field in amorphous chalcogenide film. Meanwhile, a modified thermal-assist model based on the Poole–Frenkel (PF) mechanism has been proposed to verify the thermal assistance is indispensable in the OTS process. And the modified model is well applied on the GeTe devices with different scales, which further supports the current experimental conclusion. This contributes to the further study of the OTS mechanism and application of the phase-change memory (PCM).
Numerical simulation of the atomization of liquid transverse jet in supersonic airflow
Authors: Huang Junkai , Zhao Xin , Jiang Hao
Published: May 2021

The present study provides a numerical method for liquid jet atomization in supersonic gas crossflow. Compressibility of the gas and incompressibility of the liquid are considered. High-order accurate weighted essentially non-oscillatory schemes and the Harten–Lax–van Leer contact approximate Riemann solver are used for gas flows. Liquid flow is simulated by the Chorin projection method. The motion of the sharp interface between the gas and liquid is simulated by the volume of fluid method. In order to verify the accuracy of the numerical method, numerical and experimental results for the droplet breakup in the supersonic gas flow are compared. The method is employed to simulate the liquid jet atomization in the supersonic gas crossflow. According to numerical results, the breakup process is analyzed for four different stages. The discussion for the effect of the Mach number for the gas crossflow on the liquid jet atomization is given.
Photochemistry of NH2NO2 and implications for chemistry in the atmosphere
Authors: Esposito Vincent J. , Trabelsi Tarek , Francisco Joseph S.
Published: May 2021

Recent studies have indicated that nitramide (NH2NO2) may be formed more plentifully in the atmosphere than previously thought, while also being a missing source of the greenhouse gas nitrous oxide (N2O) via catalyzed isomerization. To validate the importance of NH2NO2 in the Earth’s atmosphere, the ground and first electronic excited states of NH2NO2 were characterized and its photochemistry was investigated using multireference and coupled cluster methods. NH2NO2 is non-planar and of singlet multiplicity in the ground state while exhibiting large out-of-plane rotation in the triplet first excited state. One-dimensional cuts of the adiabatic potential energy surface calculated using the MRCI+Q method show low-lying singlet electronic states with minima in their potential along the N–N and N–O bond coordinates. Due to vertical excitation energies in the 225–180 nm region, photochemical processes will not compete in the troposphere, causing N2O production to be the predicted major removal process of NH2NO2. In the upper atmosphere, photodissociation to form NH2NO + O (3P) is suggested to be a major photochemical removal pathway.
Analysis of the relative supercooling enhancement of two emerging supercooling techniques
Authors: Câmpean Ștefan-Ioan , Beșchea George-Andrei , Șerban Alexandru , Powell-Palm Matthew J. , Rubinsky Boris , Năstase Gabriel
Published: May 2021

We present herein an experimental study on the ice-nucleation kinetics of two recently introduced aqueous supercooling modalities—oil-sealed isobaric supercooling and isochoric supercooling. A series of constant-cooling rate experiments compare the apparent nucleation temperatures of pure water supercooled under these modalities with conventional open-air isobaric supercooling, demonstrating that both methods significantly enhance the supercoolability of the system as compared to open-air supercooling. However, while the mean nucleation temperatures of the two methods are statistically comparable, isochoric supercooling displays approximately half the variability of isobaric oil-sealed supercooling, which may have important implications on the design of supercooling-based biopreservation protocols in which stability and reproducibility are paramount.