98,538 research outputs found
Synthesis and structure of the tetrameric [Cp V(mu-F)(2)](4) (Cp = C5Me5); Preparation of the imido molybdenum fluoride [(2,6-i-Pr2C6H3N)(2)MoF2]center dot THF and the structural investigation of [(2,6-i-Pr2C6H3N)(6)Mo-4(mu(3)-F)(2)Me-2(mu-O)(4)]
No full textTreating [Cp V(mu-Cl)(2)](3) (Cp = C5Me5) and [(2,6-i-Pr2C6H3N)(2)MoMe2], respectively, with Me3SnF afforded the title compounds [Cp V(mu-F)(2)](4) (1) and [(2,6-i-Pr2C6H3N)(2)MoF2] THF (2). 1 has a tetrameric structure, in which four V atoms can be regarded as being arranged at the vertices of a distorted tetrahedron, with four long edges bridged by one F atom and each of the other two short edges bridged by two F atoms with a mean V-F bond length of 2.00 Angstrom. A hydrolyzed product of 2, [(2,6-i-Pr2C6H3N)(6)Mo-4(mu(3)-F)(2)Me-2(mu-O)(4)] (3) was characterized by elemental analyses and X-ray single crystal study. The X-ray diffraction analysis reveals that 3 has a unique tetranuclear structure, containing two five and two six coordinated Mo atoms connecting each other by four mu-O and two mu(3)-F atoms. The geometries around the two Mo atoms can be described having distorted trigonal bipyramidal and distorted octahedral coordination spheres. respectively. The Mo-(mu-O) bond lengths are 1.813 Angstrom (average) for Eve coordinated Mo atoms and 2.030 Angstrom (average) for those of six coordinated, respectively, indicating an additional pi bonding between five coordinated Mo atoms and the mu-O atoms. The MO-(mu(3)-F) distances range from 2.291 to 2.352 Angstrom
Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp(3))-H and C(sp(2))-H under Rhodium(III) Catalysis
No full textPrevious direct C-H nitrogenation suffered from simple amidation/amination with limited atom-economy and is mostly limited to C(sp(2))-H substrates. In this work, anthranil was designed as a novel bifunctional aminating reagent for both C(sp(2)) H and C(sp(3)) H bonds under rhodium(III) catalysis, thus affording a nucleophilic aniline tethered to an electrophilic carbonyl. A tridendate rhodium(III) complex has been isolated as the resting state of the catalyst, and DFT studies established the intermediacy of a nitrene species
Transition-Metal-Promoted Direct C-H Cyanoalkylation and Cyanoalkoxylation of Internal Alkenes via Radical C-C Bond Cleavage of Cycloketone Oxime Esters
No full textTransition-metal-catalyzed alkyl-Heck-type cross-coupling of olefinic C-H bonds has been a challenge in the C-H activation area. Herein, we report FeCl3-promoted efficient direct C-H cyanoalkylation of internal alkenes, that is, ketene dithioacetals, with cycloketone oxime esters via radical C-C bond cleavage under the redox-neutral conditions. With CuCl2 as the catalyst under a dioxygen atmosphere direct C-H cyanoalkoxylation of the same internal alkenes was achieved. The cyanoalkylated tetrasubstituted alkene products could be diversely transformed to cyanoalkyl-funtionalized N- and S-heterocyclic compounds. The mechanistic studies have revealed that these C-H cyanoalkylation and cyanoalkoxylation reactions proceed through a radical pathway
Scanning tunneling spectroscopy on YBa2Cu3Oy/PrBa2Cu3Oy/YBa2Cu3Oy sandwiched junctions and YBa2Cu3Oy/Y0.5Pr0.5Ba2Cu3Oy superlattices
No full textRhodium(III)-Catalyzed C-C Coupling between Arenes and Aziridines by C-H Activation
No full textRhodium(III)-Catalyzed C-C Coupling between Arenes and Aziridines by C-H Activatio
δ-C(sp3)H Activation of Free Alcohols Enabled by Rationally Designed H-Bond-Acceptor Ligands
No full textThe ability to employ a wide range of native substrates is essential for the broad application of transition-metal-catalyzed C–H activation. Recent advances have made native carboxylic acids, ketones, and amines amenable to C(sp3)–H activation, but alcohols, perhaps the most common functionality in organic chemistry, have remained intractable due to their low affinity for late-transition-metal catalysts. Herein we describe the rational development of ligands to overcome this challenge and enable alcohol-directed -C(sp3)–H arylation reactions. Our ligand design strategy employs charge balance and a secondary-coordination-sphere H-bonding interaction—evidenced by SAR studies, computational modelling, and crystallographic data—to stabilize L-type hydroxyl coordination to palladium, thereby facilitating the assembly of the key C–H cleavage transition state. In contrast to prior studies in C–H activation, where secondary interactions were used to control selectivity in the context of established reactivity, this report demonstrates the feasibility of employing secondary interactions to enable challenging novel reactivity by enhancing substrate-catalyst affinity
Textbook of neonatal medicine : a Chinese perspective
No full textThis authoritative and comprehensive text is written by an internationally renowned group of medical experts of Chinese ethnic origin from the mainland, Taiwan, Hong Kong and six other countries. As a scientific and clinically practical review of current knowledge on medical care of normal and high-risk infants, this book covers the essentials of modern neonatal medicine. Conditions which are common or life-threatening have been selected for detailed description, while sufficient information is provided on uncommon or less serious problems to help gain an understanding of how they are best managed. A special emphasis has been put on describing experiences which are unique to Chinese infants. The 91 chapters reflect the personal interest and experience of the 77 contributors whose contemporary view and practical approach should prove useful for postgraduate trainees and specialists wishing to keep themselves up to date in neonatal medicinepublished_or_final_versionEditorsContributorsForewordsPrefaceIndex p8971 Organisation of Perinatal Care / Shoo K. Lee p32 Organisation of Neonatal Intensive Care / Keng-Wee Tan p93 The Expanded Role of Neonatal Nursing / Thomas T. W. Chiu p214 Perinatal-Neonatal Audit / Pak-Cheung Ng p335 Neonatal Intensive Care in Developing Countries / Chap -Yung Yeung p436 Prenatal Diagnosis for Paediatricians / Emily W. Y. Ling p517 Maternal Diseases Affecting the Fetus / Xing-Guo Liu p638 Antepartum Fetal Assessment / David T. Y. Liu p699 Intrapartum Fetal Assessment / Sze-Ya Yeh p7710 Prematurity / Tai-Fai Fok p8511 Small for Gestational Age Infants / Kuo-Inn Tsou Yau p9912 Drugs Used in Pregnancy Affecting the Fetus / Xing- Guo Liu p10913 Delivery Room Resuscitation / Gary M. Chan p11714 Perinatal Asphyxia / Victor Y. H. Yu p12515 Physical Examination / Chin-Theam Lim p13516 Birth Injuries / Nem-Yun Boo p14517 Neonatal Screening / Louis C. K. Low p15918 Care of the Normal Neonate / Michael C. K. Chan p17119 Thermoregulation / Yuh-Jyh Lin p17720 Neonatal Hypothermia and Scleroedema / Wen-Lan Hong p18721 Fluid Homeostasis / Paul Y. K. Wu p19522 Feeding the Normal Term Infant / Gary M. Chan p20723 Feeding the Preterm Infant / Victor Y. H. Yu p21524 Mineral Requirements / Winston W. K. Koo p22525 Parenteral Nutrition / Victor Y. H. Yu p23526 Respiratory Physiology / Kei Liu p24527 Prevention of Respiratory Distress Syndrome / Victor Y. H. Yu p25528 Respiratory Distress Syndrome / Tai-Fai Fok p26529 Meconium Aspiration Syndrome / Chyi-Her Lin p27530 Pneumonia / Zhi-Zhi Xu p27931 Pulmonary Haemorrhage / Yan-Ming Xie p28532 Pulmonary Air Leak / Yu-Ming Zhang p28933 Assisted Ventilation / Jen-Tien Wung p29734 Chronic Lung Disease / Victor Y. H. Yu p30935 Apnoea / Lai-Yun Ho p31936 Congenital Diaphragmatic Hernia / Jen-Tien Wung p33337 Cardiovascular Adaptation to Postnatal Life / Alice C. Yao p34338 Persistent Pulmonary Hypertension / Victor Y. H. Yu p35539 Patent Ductus Arteriosus / Yuh-Jyh Lin p36340 Evaluation and Management of Cardiac Disease / Maurice P. Leung p37141 Medical and Surgical Therapy of Cardiac Disease / Maurice P. Leung p38342 Arrhythmias / Pierre C. Wong p39543 Neonatal Shock / Yu-Kun Han p40944 Neonatal Jaundice / Kim-Leong Tan p41745 Feeding Problems / De-Ming Huang p42946 Necrotising Enterocolitis / Victor Y. H. Yu p43747 Cholestasis in Infancy / Mei-Hwei Chang p45148 Disorders of Blood Glucose Homeostasis / Katherine C. H. King p46549 Infant of the Diabetic Mother / Hun-Seng Chao p47950 Metabolic Bone Diseases / Winston W. K. Koo p48751 Congenital Hypothyroidism / Xi-Ji Guan p49552 Hereditary Metabolic Diseases / Paul W. K. Wong p50353 Miscellaneous Endocrine Problems / Louis C. K. Low p51354 Haemolytic Disease of the Newborn / Shu-Zhong Shi p52555 Polycythaemia-Hyperviscosity Syndrome / Wan-Jun Liu p53156 Miscellaneous Haematological Disorders / Ka-Wah Chan p53757 Red Blood Cell Transfusion / Victor Y. H. Yu p54558 Acute Renal Failure / Ke-Lun Wei p55359 Neonatal Renal Disorders / Sik-Nin Wong p55960 Neonatal Neurological Assessment / Barbara Lam p57161 Hypoxic-Ischaemic Encephalopathy / Victor Y. H. Yu p57962 Intracranial Haemorrhage / Barbara Lam p58963 Neonatal Seizures / Zi-Li Chen p59964 Neonatal Pain / T. H. H. Guan Koh p60765 Intrauterine Infections / Cheng T. Cho p61966 Immunological Defences / Yu-Lung Lau p63567 Bacterial Infections / Cheng T. Cho p64968 Neonatal Tetanus / Michael C. K. Chan p66169 Fungal Infections / Pak-Cheung Ng p66570 Nosocomial Infections and Infection Control / Tom D. Y. Chin p67771 Neonatal Immunisation / Yu-Lung Lau p68572 Applications of DNA Technology in Clinical Genetics / Ivy Ng p69973 Chromosome Abnormalities / Lai-Yun Ho p70574 Congenital Malformations / Nai-Kiong Ho p71775 The Dysmorphic Infant / Lai-Yun Ho p72376 Mode of Inheritance / Lai-Yun Ho p73177 Genetic Counselling / Lai-Yun Ho p74178 Practical Neonatal Procedures / Chin-Theam Lim p75179 Neonatal Pharmacology / Emily W. Y. Ling p76380 Neonatal Anaesthesia / Lena S. Sun p79381 Neonatal Surgery / Chung-Kwong Yeung p80382 Communicating with Parents of Sick Babies / T. H. H. Guan Koh p81983 Outcome of Very Low Birthweight Infants / Victor Y. H. Yu p82984 Costs of Neonatal Intensive Care and Long-Term Disabilities / Shoo K. Lee p83985 Ethical Issues in Neonatal Intensive Care / Emily W. Y. Ling p84786 Perinatal-Neonatal Health Care in China / Xiao-Cheng Ji p85987 Intrauterine Growth Retardation in China: Fetal Aspects / Xing-Hua Huang p86588 Intrauterine Growth Retardation in China: Neonatal Aspects / Shi-Min Zhao p87189 Chinese Neonates Are Different / Chap-Yung Yeung p87790 Neonatal Sepsis in China / Shi-Xiao Wu p88591 Traditional Chinese Neonatal Medicine / Bao-Lin Zhang p88
Improved measurement of the branching fraction of h c → γη′/η and search for h c → γπ 0
No full textAbstract The processes h c → γP (P = η′, η, π 0) are studied with a sample of (27.12 ± 0.14) × 108 ψ(3686) events collected by the BESIII detector at the BEPCII collider. The decay h c → γη is observed for the first time with the significance of 9.0 σ, and the branching fraction is determined to be (3.77 ± 0.55 ± 0.13 ± 0.26) × 10 −4, while B (h c → γη′) is measured to be (1.40 ± 0.11 ± 0.04 ± 0.10) × 10 −3, where the first uncertainties are statistical, the second systematic, and the third from the branching fraction of ψ(3686) → π 0 h c . The combination of these results allows for a precise determination of R h c = B h c → γη B h c → γ η ′ , which is calculated to be (27.0 ± 4.4 ± 1.0)%. The results are valuable for gaining a deeper understanding of η − η′ mixing, and its manifestation within quantum chromodynamics. No significant signal is found for the decay h c → γπ 0, and an upper limit is placed on its branching fraction of B (h c → γπ 0) < 5.0 × 10 −5, at the 90% confidence level
A 13-bit Temperature Sensor with a ±1.45°C (3σ) Inaccuracy from -55°C to 125°C
No full textThis paper introduces a bipolar junction transistor (BJT)-based CMOS temperature-to-digital converter (TDC) that demonstrates an accuracy of ±1.45°C (3σ) within a temperature range of -55°C to 125°C, achieved without the need for calibration. This result is attributed to the implementation of a second-order curvature compensation technique, which utilizes a switched capacitor integral circuit within the bandgap reference circuit. This approach effectively mitigates higher-order reference voltage errors, enhancing overall precision. Additionally, the paper incorporates dynamic element matching (DEM) and auto-zeroing techniques, applied in successive amplification stages, to minimize errors originating from current mirror mismatches and operational amplifier offset voltages, respectively. The described BJT-based sensor features a 13-bit successive-approximationregister analog-to-digital converter (SAR ADC), comprising a 5-bit capacitive array and an 8-bit resistor-capacitor hybrid array, designed to monitor and digitally record temperature data. The proposed design operates within a supply voltage range of 2.7V to 5.5V and is realized using a 0.6 μm BJT process, ultimately achieving a resolution of 29.7 mK
Search for new hadronic decays of h c and observation of h c → p p ¯ η
No full textAbstract A search for the hadronic decays of the h c meson to the final states p p ¯ π + π − π 0, p p ¯ η , and p p ¯ π 0 via the process ψ(3686) → π 0 h c is performed using (4.48 ± 0.03) × 108 ψ(3686) events collected with the BESIII detector. The decay channel h c → p p ¯ η is observed for the first time with a significance greater than 5σ and a branching fraction of (6.41 ± 1.74 ± 0.53 ± 1.00) × 10 −4, where the uncertainties are statistical, systematic, and that from the branching fraction of ψ(3686) → π 0 h c . Strong evidence for the decay h c → p p ¯ π + π − π 0 is found with a significance of 4.9σ and a branching fraction of (3.84 ± 0.83 ± 0.69 ± 0.58) × 10 −3. The significances include systematic uncertainties. No clear signal of the decay h c → p p ¯ π 0 is found, and an upper limit of 6.59 × 10 −4 on its branching fraction is set at the 90% confidence level
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