Studies of Soluble Polymer-supported Organocatalysts

Polymer-supported reagents and catalysts have been extensively studied in the past few decades as they not only facilitate separation and isolation of products after reactions but also enable reuse of reagents/catalysts. In particular, chemistry using polymer-supported organocatalysts has the advantage of avoiding the use of sometimes toxic transition metals. Since organocatalysts are often used at high mol% loading in catalytic reactions, immobilizing organocatalysts on polymers for recycling and reusing makes chemistry using organocatalysts attractive in larger scale syntheses. Chapter II of this dissertation focuses on using variable temperature 31P NMR spectroscopy to study and compare the dynamic behavior of silver complexes prepared from soluble polymer-supported phosphines and electronically similar low molecular weight phosphine ligands. The phosphine-silver complexes supported on terminally functionalized polyisobutylene (PIB) and poly(ethylene glycol) show similar kinetic behavior compared to their low molecular weight counterparts. However, the dynamic behavior of phosphine-silver complexes supported as pendent groups on a linear polystyrene is difficult to study because of significant line-broadening on 31P NMR spectra. Chapter III of this dissertation aims at examining the recyclability and reusability of PIB-supported phosphines as organocatalysts and reagents. PIB-supported alkyldiphenyl- and aryldiphenylphosphines were prepared and used as recyclable organocatalysts in addition and allylic amination reactions. The PIB-bound phosphines were useful reagents in aza-Wittig and Mitsunobu reactions. The PIB-bound phosphine oxides formed either from adventitious oxidation or during the course of reactions can be reduce to PIB-phosphines for reuse. Chapter IV of this dissertation describes preliminary studies on soluble polymer-supported N-heterocyclic carbene (NHC) organocatalysts. PIB- and polyethylene oligomer (PE_Olig)-supported NHC adducts were synthesized and the corresponding polymer-supported NHC catalysts were generated in situ in lactide polymerization and phenyl isocyanate trimerization reactions. The PIB-bound NHC catalyst generated in situ was not recyclable in a lactide polymerization. However, PIB- and PEOlig-bound NHC precatalysts showed modest recyclability in lactide polymerization and phenyl isocyanate trimerizations

Test-time Defense against Adversarial Attacks: Detection and Reconstruction of Adversarial Examples via Masked Autoencoder

Existing defense methods against adversarial attacks can be categorized into training time and test time defenses. Training time defense, i.e., adversarial training, requires a significant amount of extra time for training and is often not able to be generalized to unseen attacks. On the other hand, test time defense by test time weight adaptation requires access to perform gradient descent on (part of) the model weights, which could be infeasible for models with frozen weights. To address these challenges, we propose DRAM, a novel defense method to Detect and Reconstruct multiple types of Adversarial attacks via Masked autoencoder (MAE). We demonstrate how to use MAE losses to build a KS-test to detect adversarial attacks. Moreover, the MAE losses can be used to repair adversarial samples from unseen attack types. In this sense, DRAM neither requires model weight updates in test time nor augments the training set with more adversarial samples. Evaluating DRAM on the large-scale ImageNet data, we achieve the best detection rate of 82% on average on eight types of adversarial attacks compared with other detection baselines. For reconstruction, DRAM improves the robust accuracy by 6% ~ 41% for Standard ResNet50 and 3% ~ 8% for Robust ResNet50 compared with other self-supervision tasks, such as rotation prediction and contrastive learning

THE KINEMATIC ANALYSIS of BASKETBALL THREE POINT SHOOT AFTER HIGH INTENSITY PROGRAM

The purpose of this study was to analyze kinetic and kinematic characteristics of three points shooting by high speed camera. Basketball players have to finish the high intensity program which was designed from simulative basketball games. The high intensity testing program includes dribbling, sprint, slide, jump shooting and three points shooting. The results of the experiments indicated that elbow, wrist, hip and ankle joints angle velocities would decrease, except the knee joint, after the high intensity program. The knee angle of take-off would also increase. It indicated that the upper limb joints angular velocity would decrease and players had to increase knee joint angular velocity to maintain original power. The time from take-off to ball release also decreased which means that there was a change in the coordinates in knee joint and elbow joint. After high intensity program the elbow and knee joints extension were closed to produce more power for the shot

Multiple Events of Allopolyploidy in the Evolution of the Racemose Lineages in Prunus (Rosaceae) Based on Integrated Evidence from Nuclear and Plastid Data.

Prunus is an economically important genus well-known for cherries, plums, almonds, and peaches. The genus can be divided into three major groups based on inflorescence structure and ploidy levels: (1) the diploid solitary-flower group (subg. Prunus, Amygdalus and Emplectocladus); (2) the diploid corymbose group (subg. Cerasus); and (3) the polyploid racemose group (subg. Padus, subg. Laurocerasus, and the Maddenia group). The plastid phylogeny suggests three major clades within Prunus: Prunus-Amygdalus-Emplectocladus, Cerasus, and Laurocerasus-Padus-Maddenia, while nuclear ITS trees resolve Laurocerasus-Padus-Maddenia as a paraphyletic group. In this study, we employed sequences of the nuclear loci At103, ITS and s6pdh to explore the origins and evolution of the racemose group. Two copies of the At103 gene were identified in Prunus. One copy is found in Prunus species with solitary and corymbose inflorescences as well as those with racemose inflorescences, while the second copy (II) is present only in taxa with racemose inflorescences. The copy I sequences suggest that all racemose species form a paraphyletic group composed of four clades, each of which is definable by morphology and geography. The tree from the combined At103 and ITS sequences and the tree based on the single gene s6pdh had similar general topologies to the tree based on the copy I sequences of At103, with the combined At103-ITS tree showing stronger support in most clades. The nuclear At103, ITS and s6pdh data in conjunction with the plastid data are consistent with the hypothesis that multiple independent allopolyploidy events contributed to the origins of the racemose group. A widespread species or lineage may have served as the maternal parent for multiple hybridizations involving several paternal lineages. This hypothesis of the complex evolutionary history of the racemose group in Prunus reflects a major step forward in our understanding of diversification of the genus and has important implications for the interpretation of its phylogeny, evolution, and classification

Shikonin enhances efficacy of a gene-based cancer vaccine via induction of RANTES

<p>Abstract</p> <p>Background</p> <p>Shikonin, a phytochemical purified from <it>Lithospermum erythrorhizon</it>, has been shown to confer diverse pharmacological activities, including accelerating granuloma formation, wound healing, anti-inflammation and others, and is explored for immune-modifier activities for vaccination in this study. Transdermal gene-based vaccine is an attractive approach for delivery of DNA transgenes encoding specific tumor antigens to host skin tissues. Skin dendritic cells (DCs), a potent antigen-presenting cell type, is known to play a critical role in transmitting and orchestrating tumor antigen-specific immunities against cancers. The present study hence employs these various components for experimentation.</p> <p>Method</p> <p>The mRNA and protein expression of RANTES were detected by RT-PCR and ELISA, respectively. The regional expression of RANTES and tissue damage in test skin were evaluated via immunohistochemistry assay. Fluorescein isothiocyanate sensitization assay was performed to trace the trafficking of DCs from the skin vaccination site to draining lymph nodes. Adjuvantic effect of shikonin on gene gun-delivered human gp100 (hgp100) DNA cancer vaccine was studied in a human gp100-transfected B16 (B16/hgp100) tumor model.</p> <p>Results</p> <p>Among various phytochemicals tested, shikonin induced the highest level of expression of RANTES in normal skin tissues. In comparison, mouse RANTES cDNA gene transfection induced a higher level of mRANTES expression for a longer period, but caused more extensive skin damage. Topical application of shikonin onto the immunization site before gene gun-mediated vaccination augmented the population of skin DCs migrating into the draining lymph nodes. A hgp100 cDNA gene vaccination regimen with shikonin pretreatment as an adjuvant in a B16/hgp100 tumor model increased cytotoxic T lymphocyte activities in splenocytes and lymph node cells on target tumor cells.</p> <p>Conclusion</p> <p>Together, our findings suggest that shikonin can effectively enhance anti-tumor potency of a gene-based cancer vaccine via the induction of RANTES expression at the skin immunization site.</p

Fabrication of multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors by using CF4 plasma treatment

Multianalyte CeO2 biosensors have been demonstrated to detect pH, glucose, and urine concentrations. To enhance the multianalyte sensing capability of these biosensors, CF4 plasma treatment was applied to create nanograin structures on the CeO2 membrane surface and thereby increase the contact surface area. Multiple material analyses indicated that crystallization or grainization caused by the incorporation of flourine atoms during plasma treatment might be related to the formation of the nanograins. Because of the changes in surface morphology and crystalline structures, the multianalyte sensing performance was considerably enhanced. Multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors exhibit potential for use in future biomedical sensing device applications

Viral load and clinical features in children infected with seasonal influenza B in 2006/2007

Background/PurposeIn influenza B infection, viral load is believed to be related to the severity of clinical illness. The correlation between viral load and symptoms is not known. We conducted a study to assess the relationship between virus load and clinical features in children infected with influenza B, in the hope that clinical features could be used as surrogate markers of viral load to guide treatment.MethodsBetween December 2006 and February 2007, 228 patients with fever and respiratory symptoms were prospectively enrolled in our tertiary hospital-based study. Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to determine viral load.ResultsReal-time RT-PCR was positive for influenza B in 76 patients. Using virus culture as the gold standard, the sensitivity and specificity were 95% and 87%, respectively. Influenza culture positive rate significantly correlated with viral load (p = 0.03). The median copy number of influenza B virus in the 76 RT-PCR positive patients was 9735 copies/ml (range 4.8×101–2.0×106 copies/ml). Samples obtained later in the clinical course tended to have lower viral load (p = 0.7), while patient age (p = 0.72) and fever duration (p = 0.96) positively related to viral load. In patients >3 years of age, myalgia was related to statistically lower viral loads (14300 vs. 1180; p = 0.025). Patients with chills tended to have higher viral loads (72450 vs. 7640; p = 0.1). Patients with abdominal pain tended to have lower viral loads (1998 vs. 12550; p = 0.06).ConclusionCulture rate positively correlated with viral load. Patients with myalgia had a lower viral load

Tuberculosis in Children and Adolescents, Taiwan, 1996–2003

Analysis of data from Taiwan’s National Tuberculosis (TB) Registry showed that incidence of TB in persons <20 years of age was 9.61/100,000 person-years, biphasic, and age-relevant, with a major peak in persons slightly >12 years. Aboriginal children were 8.1–17.4× more likely to have TB than non-Aboriginal children