Synthetic Studies Toward Complex Polycyclic Natural Products

The first chapter of this dissertation describes the use of an intramolecular Staudinger/aza-Wittig reaction in the synthesis of 1,2,5,6-tetrahydro-1,2,4-triazines, a structural motif of the natural product noelaquinone. The DEF ring system of noelaquinone was prepared in 13 steps and 2% overall yield with key steps featuring a Cu(I)-catalyzed C-arylation and the controlled acidic hydrolysis of the PMB protective group. The second chapter describes the investigation of reactions between methyl 3-oxo-2-oxabicyclo[2.2.0]hexane-6-carboxylate and an indolo-indoline dimer in the presence of BF3·OEt2. Two tricyclic-fused heterocyclic products and a diene carboxylic acid have been obtained through a ring opening process, a retro-[2+2] cycloaddition, and a conjugate addition from the indole fragment. The third chapter describes progress toward the total synthesis of haouamine A. Several routes to the marine alkaloid have been attempted. The challenges associated with the late stage lactam reduction, epoxidation, and aromatization strategy to prepare the necessary tetrahydropyridine and aza-cyclophane moieties are discussed

Secure Mobile Agents in Electronic Commerce by Using Undetachable Signatures from Pairings

It is expect that mobile agents technology will bring significant benefits to electronic commerce. But security issues, especially threats from malicious hosts, become a great obstacle of widespread deployment of applications in electronic commerce based on mobile agents technology. Undetachable digital signature is a category of digital signatures to secure mobile agents against malicious hosts. An undetachable signature scheme by using encrypted functions from bilinear pairings was proposed in this paper. The security of this scheme base on the computational intractability of discrete logarithm problem and computational Diffe-Hellman problem on gap Diffle-Hellman group. Furthermore, the scheme satisfies all the requirements of a strong non-designated proxy signature i.e. verifiability, strong unforgeability, strong identifiability, strong undeniability and preventions of misuse. An undetachable threshold signature scheme that enable the customer to provide n mobile agents with ‘shares’ of the undetachable signature function is also provided. It is able to provide more reliability than classical undetachable signatures

DETC2005-84151 FINITE ELEMENT ANALYSIS FOR INTERIOR BOOMING NOISE REDUCTION IN A TRACTOR CABIN

ABSTRACT This paper presents a finite element approach to analyze the "boom" noise for a compact tractor cabin. The tractor cabin is initially designed to have a structure made up of steel beams and aluminum panels, as well as PMAA panels in windshield, backlight and windows. Cavity acoustic modes of the cab are evaluated and the acoustic resonant frequencies are identified. The study on the structural-borne noise from the cabin structural vibration generated by the engine of the vehicle is performed. A coupled-field finite element model, counting the interactions between the air fluid inside the cabin compartment and the cabin exterior structure, is presented for investigating the structural-borne noise in a low frequency range of 20 Hz to 80 Hz. This range has shown strong boom effects. The interior noise level at driver's right ear position is investigated. The peak noise levels at the position are determined. The effects of additional stiffeners and damping layers on the boom noise are also investigated

Evolution of Interlayer Coupling in Twisted MoS2 Bilayers

Van der Waals (vdW) coupling is emerging as a powerful method to engineer and tailor physical properties of atomically thin two-dimensional (2D) materials. In graphene/graphene and graphene/boron-nitride structures it leads to interesting physical phenomena ranging from new van Hove singularities1-4 and Fermi velocity renormalization5, 6 to unconventional quantum Hall effects7 and Hofstadter's butterfly pattern8-12. 2D transition metal dichalcogenides (TMDCs), another system of predominantly vdW-coupled atomically thin layers13, 14, can also exhibit interesting but different coupling phenomena because TMDCs can be direct or indirect bandgap semiconductors15, 16. Here, we present the first study on the evolution of interlayer coupling with twist angles in as-grown MoS2 bilayers. We find that an indirect bandgap emerges in bilayers with any stacking configuration, but the bandgap size varies appreciably with the twist angle: it shows the largest redshift for AA- and AB-stacked bilayers, and a significantly smaller but constant redshift for all other twist angles. The vibration frequency of the out-of-plane phonon in MoS2 shows similar twist angle dependence. Our observations, together with ab initio calculations, reveal that this evolution of interlayer coupling originates from the repulsive steric effects, which leads to different interlayer separations between the two MoS2 layers in different stacking configurations

Protective effect of Wuling mycelia, alone and in combination with valproic acid, on pentylenetetrazolinduced epilepsy in rats

Purpose: To determine the inhibitory effects of Wuling mycelia, alone and in combination with valproic acid (VPA) on pentylenetetrazol (PTZ)-induced epileptic seizure in rats, and their protective effects on cognitive impairment.Methods: Sprague-Dawley rats were randomly divided into five groups: control (sham), model, Wuling mycelia, VPA and combination groups. Rats in Wuling mycelia group were given oral Wuling mycelia alone at a dose of 594 mg/kg, while those in VPA group were given oral VPA alone at a dose of 189 mg/kg. In the combination group, rats received oral VPA at a dose of 189 mg/kg co-administered with Wuling mycelia at a dose of 594 mg/kg. One hour after the treatments, the control group was injected with physiological saline intraperitoneally, while the other four groups were injected with PTZ solution once a day for 28 days. Subsequently, seizure intensity, cognitive impairment, neuronal loss and hippocampal expressions of IL-1β, NF-ĸB/p65 and TLR4 were determine in all groups.Results: Combined use of Wuling mycelium and VPA significantly reduced the frequency and the grade of seizures (p <0.01), and also decreased the degree of cognitive impairment (p <0.05). There were marked increases in neuronal damage and hippocampal  expression levels of NF-ĸB/p65, TLR4 and IL1β (inflammatory cytokines) in the model group (p < 0.05). However, these changes were  reversed in the combination treatment group (p < 0.05).Conclusion: Wuling mycelia is a potentially effective adjunct drug for the treatment of refractory epilepsy. The underlying mechanism might involve downregulations of NF-ĸB/p65, TLR4 and IL-1β. Keywords: Wuling mycelia, Refractory epilepsy, Seizure, Traditional Chinese medicine, Hippocampal area, HMGB1/TLR4/NF-κB  signalling pathway, IL-1β, NF-ĸB/p65, TLR

Clinical analysis of infectious mononucleosis complicated with acute acalculous cholecystitis

ObjectiveThis study aimed to investigate specific clinical diagnostic methods for children with infectious mononucleosis (IM) complicated by acute acalculous cholecystitis (AAC).MethodsWe conducted a retrospective analysis of 171 cases of IM diagnosed in the infectious disease ward of Children's Hospital of Nanjing Medical University between January 2020 and December 2020. All IM patients underwent abdominal ultrasound examinations to assess the liver, gallbladder, and spleen. Fourteen patients with symptoms of AAC underwent a follow-up assessment one week later.ResultsThe estimated incidence of AAC in hospitalized IM children was 8.2%. Both groups of patients presented with fever, abdominal pain, and eyelid edema upon admission. Characteristic radiological findings of AAC were observed, including gallbladder (GB) distention, increased GB wall thickness and increased common bile duct diameter. Analysis of laboratory results revealed no statistically significant differences in leukocyte, absolute lymphocyte count, CD3+, CD3 + CD4+, CD3+ CD8+, Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), or Gamma-Glutamyl Transferase (GGT) levels between the AAC(+) and AAC(−) groups on admission. However, these parameters were not significant risk factors for AAC. After discharge, relevant indicators in non-AAC patients gradually decreased to normal levels, while those in AAC(+) patients did not show a significant decrease.ConclusionWhile cases of IM complicated by AAC are relatively uncommon, the utilization of abdominal ultrasound offers a reliable tool for confirming this diagnosis. Routine abdominal ultrasound examinations are recommended for IM patients to improve early detection and treatment of associated conditions

Current Status of the Chinese National Twin Registry

The Chinese National Twin Registry is the first and largest population-based twin registry in China. It was established in 2001. The primary goal of this program is the establishment of a population-based twin registry of 45,000 twin pairs from several regions representing north, south, urban, and rural areas in China. A secondary goal is to study genetic contributions to complex diseases, and to test associations of candidate genes with related phenotypes. Seven thousand, four hundred and twenty-three twin pairs have been enrolled in the registry in which 1613 pairs have undergone detailed questionnaire assessments and physical examination. Based on the baseline registry, a twin cohort was established. Continued research includes studies on intermediate phenotypes of cardiovascular and cerebrovascular diseases and psychological studies in adult twins, studies on growth and development in adolescent twins, and so forth. The current state and future plans for the Chinese National Twin Registry will be discussed in this article.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000243216600009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Genetics & HeredityObstetrics & GynecologySCI(E)PubMed17ARTICLE6747-752

Anti-sulfatide antibody-related Guillain–Barré syndrome presenting with overlapping syndromes or severe pyramidal tract damage: a case report and literature review

IntroductionAnti-sulfatide antibodies are key biomarkers for the diagnosis of Guillain–Barré syndrome (GBS). However, case reports on anti-sulfatide antibody-related GBS are rare, particularly for atypical cases.Case description, case 1A 63 years-old man presented with limb numbness and diplopia persisting for 2 weeks, with marked deterioration over the previous 4 days. His medical history included cerebral infarction, diabetes, and coronary atherosclerotic cardiomyopathy. Physical examination revealed limited movement in his left eye and diminished sensation in his extremities. Initial treatments included antiplatelet agents, cholesterol-lowering drugs, hypoglycemic agents, and medications to improve cerebral circulation. Despite this, his condition worsened, resulting in bilateral facial paralysis, delirium, ataxia, and decreased lower limb muscle strength. Treatment with intravenous high-dose immunoglobulin and dexamethasone resulted in gradual improvement. A 1 month follow-up revealed significant neurological sequelae.Case description, case 2A 53 years-old woman was admitted for adenomyosis and subsequently experienced sudden limb weakness, numbness, and pain that progressively worsened, presenting with diminished sensation and muscle strength in all limbs. High-dose intravenous immunoglobulin, vitamin B1, and mecobalamin were administered. At the 1 month follow-up, the patient still experienced limb numbness and difficulty walking. In both patients, albuminocytologic dissociation was found on cerebrospinal fluid (CSF) analysis, positive anti-sulfatide antibodies were detected in the CSF, and electromyography indicated peripheral nerve damage.ConclusionAnti-sulfatide antibody-related GBS can present with Miller–Fisher syndrome, brainstem encephalitis, or a combination of the two, along with severe pyramidal tract damage and residual neurological sequelae, thereby expanding the clinical profile of this GBS subtype. Anti-sulfatide antibodies are a crucial diagnostic biomarker. Further exploration of the pathophysiological mechanisms is necessary for precise treatment and improved prognosis

Buckwheat Honey Attenuates Carbon Tetrachloride-Induced Liver and DNA Damage in Mice

Buckwheat honey, which is widely consumed in China, has a characteristic dark color. The objective of this study was to investigate the protective effects of buckwheat honey on liver and DNA damage induced by carbon tetrachloride in mice. The results revealed that buckwheat honey had high total phenolic content, and rutin, hesperetin, and p-coumaric acid were the main phenolic compounds present. Buckwheat honey possesses super DPPH radical scavenging activity and strong ferric reducing antioxidant power. Administration of buckwheat honey for 10 weeks significantly inhibited serum lipoprotein oxidation and increased serum oxygen radical absorbance capacity. Moreover, buckwheat honey significantly inhibited aspartate aminotransferase and alanine aminotransferase activities, which are enhanced by carbon tetrachloride. Hepatic malondialdehyde decreased and hepatic antioxidant enzymes (superoxide dismutase and glutathione peroxidase) increased in the presence of buckwheat honey. In a comet assay, lymphocyte DNA damage induced by carbon tetrachloride was significantly inhibited by buckwheat honey. Therefore, buckwheat honey has a hepatoprotective effect and inhibits DNA damage, activities that are primarily attributable to its high antioxidant capacity

Synchronous multimode ultrasound for assessing right-to-left shunt: a prospective clinical study

BackgroundRight-to-left shunt (RLS) is associated with several conditions and causes morbidity. In this study, we aimed to evaluate the effectiveness of synchronous multimode ultrasonography in detecting RLS.MethodsWe prospectively enrolled 423 patients with high clinical suspicion of RLS and divided them into the contrast transcranial Doppler (cTCD) group and synchronous multimode ultrasound group, in which both cTCD and contrast transthoracic echocardiography (cTTE) were performed during the same process of contrast-enhanced ultrasound imaging. The simultaneous test results were compared with those of cTCD alone.ResultsThe positive rates of grade II (22.0%:10.0%) and III (12.7%:10.8%) shunts and the total positive rate (82.1748%) in the synchronous multimode ultrasound group were higher than those in the cTCD alone group. Among patients with RLS grade I in the synchronous multimode ultrasound group, 23 had RLS grade I in cTCD but grade 0 in synchronous cTTE, whereas four had grade I in cTCD but grade 0 in synchronous cTTE. Among patients with RLS grade II in the synchronous multimode ultrasound group, 28 had RLS grade I in cTCD but grade II in synchronous cTTE. Among patients with RLS grade III in the synchronous multimode ultrasound group, four had RLS grade I in cTCD but grade III in synchronous cTTE. Synchronous multimode ultrasound had a sensitivity of 87.5% and specificity of 60.6% in the patent foramen ovale (PFO) diagnosis. Binary logistic regression analyses showed that age (odds ratio [OR] = 1.041) and risk of paradoxical embolism score ≥ 7 (OR = 7.798) were risk factors for stroke recurrence, whereas antiplatelets (OR = 0.590) and PFO closure with antiplatelets (OR = 0.109) were protective factors.ConclusionSynchronous multimodal ultrasound significantly improves the detection rate and test efficiency, quantifies RLS more accurately, and reduces testing risks and medical costs. We conclude that synchronous multimodal ultrasound has significant potential for clinical applications