86 research outputs found
Jablotron 100-Based Corporation Access System
Bakalářská práce se zabĂ˝vá problematikou návrhu a realizace pĹ™ĂstupovĂ©ho systĂ©mu podniku s elektronickĂ˝m zabezpeÄŤovacĂm systĂ©mem Jablotron 100 a jeho propojenĂm s jinĂ˝mi systĂ©my. Byl navrĹľen a naprogramován mĹŻstek s API rozhranĂm pro ovládánĂ systĂ©mu Jablotron 100. Tento mĹŻstek byl pouĹľit pro realizaci webovĂ©ho uĹľivatelskĂ©ho rozhranĂ k ovládánĂ pĹ™ĂstupovĂ©ho systĂ©mu. Dále byl vytvoĹ™en koncept zĂskávánĂ dat docházky ze systĂ©mu Jablotron 100.This bachelor thesis deals with the design and implementation of an enterprise access control system based on the electronic security system Jablotron 100 and its connection with external systems. The bridge with an API interface for controlling the Jablotron 100-based corporation access system has been designed and programmed. This bridge was used to implement the web user interface to control the access system. Furthermore, the concept of collecting attendance data from the Jablotron 100-based system was created.
Adaptive Algorithm for Multi-armed Bandit Problem with High-dimensional Covariates
This paper studies an important sequential decision making problem known as the multi-armed stochastic bandit problem with covariates. Under a linear bandit framework with high-dimensional covariates, we propose a general multi-stage arm allocation algorithm that integrates both arm elimination and randomized assignment strategies. By employing a class of high-dimensional regression methods for coefficient estimation, the proposed algorithm is shown to have near optimal finite-time regret performance under a new study scope that requires neither a margin condition nor a reward gap condition for competitive arms. Based on the synergistically verified benefit of the margin, our algorithm exhibits adaptive performance that automatically adapts to the margin and gap conditions, and attains optimal regret rates simultaneously for both study scopes, without or with the margin, up to a logarithmic factor. Besides the desirable regret performance, the proposed algorithm simultaneously generates useful coefficient estimation output for competitive arms and is shown to achieve both estimation consistency and variable selection consistency. Promising empirical performance is demonstrated through extensive simulation and two real data evaluation examples.</p
Biocatalytic Formal Anti-Markovnikov Hydroamination and Hydration of Aryl Alkenes
Biocatalytic
anti-Markovnikov alkene hydroamination and hydration
were achieved based on two concepts involving enzyme cascades: epoxidation–isomerization–amination
for hydroamination and epoxidation–isomerization–reduction
for hydration. An <i>Escherichia coli</i> strain coexpressing
styrene monooxygenase (SMO), styrene oxide isomerase (SOI), ω-transaminase
(CvTA), and alanine dehydrogenase (AlaDH) catalyzed the hydroamination
of 12 aryl alkenes to give the corresponding valuable terminal amines
in high conversion (many ≥86%) and exclusive anti-Markovnikov
selectivity (>99:1). Another <i>E. coli</i> strain coexpressing
SMO, SOI, and phenylacetaldehyde reductase (PAR) catalyzed the hydration
of 12 aryl alkenes to the corresponding useful terminal alcohols in
high conversion (many ≥80%) and very high anti-Markovnikov
selectivity (>99:1). Importantly, SOI was discovered for stereoselective
isomerization of a chiral epoxide to a chiral aldehyde, providing
some insights on enzymatic epoxide rearrangement. Harnessing this
stereoselective rearrangement, highly enantioselective anti-Markovnikov
hydroamination and hydration were demonstrated to convert α-methylstyrene
to the corresponding (<i>S</i>)-amine and (<i>S</i>)-alcohol in 84–81% conversion with 97–92% <i>ee</i>, respectively. The biocatalytic anti-Markovnikov hydroamination
and hydration of alkenes, utilizing cheap and nontoxic chemicals (O<sub>2</sub>, NH<sub>3</sub>, and glucose) and cells, provide an environmentally
friendly, highly selective, and high-yielding synthesis of terminal
amines and alcohols
Enantioselective Alkyne Conjugate Addition Enabled by Readily Tuned Atropisomeric <i>P</i>,<i>N</i>‑Ligands
By
the nature of its structure, the 5-membered chiral biaryl heterocyclic
scaffold represents a departure from 6-membered <i>P</i>,<i>N</i>-ligands that facilitates tuning and enables ligand
evolution to address issues of selectivity and reactivity. In this
vein, the Cu-catalyzed enantioselective conjugate alkynylation of
Meldrum’s acid acceptors is reported using Me-StackPhos. Enabled
by this new ligand, the reaction tolerates a wide range of alkynes
furnishing the products in high yields and excellent enantioselectivity.
The transformation provides access to highly useful chiral β-alkynyl
Meldrum’s acid building blocks as demonstrated by an efficient
enantioselective synthesis of the preclinical agent OPC 51803
Thioketal-Based Electrochemical Sensor Reveals Biphasic Effects of l‑DOPA on Neuroinflammation
Neuroinflammation is linked closely
to neurodegenerative diseases,
with reactive oxygen species (ROS) exacerbating neuronal damage. Traditional
electrochemical sensors show promise in targeting cellular ROS to
understand their role in neuropathogenesis and assess therapies. Nevertheless,
these sensors face challenges in mitigating the ROS oxidation overpotential.
We herein introduce an ROS oxidation-independent nucleic acid sensor
for in situ ROS analysis and therapeutic assessment. The sensor comprises
ionizable and thioketal (TK)-based lipids with methylene blue-tagged
nucleic acids on a glass carbon electrode. ROS exposure triggers cleavage
within the sensor’s thioketal moiety, detaching the nucleic
acid from the electrode and yielding quantifiable results via square-wave
voltammetry. Importantly, the sensor’s low potential window
minimizes interference, ensuring precise ROS measurements with high
selectivity. Using this sensor, we unveil levodopa’s dose-dependent
biphasic effect on neuroinflammation: low doses alleviate oxidative
stress, while high doses exacerbate it. The TK-based sensor offers
a promising methodology for investigating neuroinflammation’s
pathogenesis and screening potential treatments, advancing neurodegenerative
disease research
Catalytic Dehydrative Lactonization of Allylic Alcohols
A convenient strategy for the synthesis
of phthalides and Îł-butyrolactones
is reported. The method utilizes readily prepared allylic alcohols
in formal AuÂ(I)- and PdÂ(II)-catalyzed S<sub>N</sub>2′ reactions.
Using these catalysts, exclusive formation of the desired five-membered
lactones is observed, completely avoiding the competing direct lactonization
pathway that forms the undesired seven-membered ring with protic acids
and alternative metal salts. This mild and operationally simple method
notably tolerates exomethylene groups and should find use in both
phthalide and terpene syntheses
Mankin's scoring for the cartilage degradation.
<p>Mankin's scoring for the cartilage degradation.</p
Histological assessment of cartilage restoring effects of the three groups.
<p>The left two columns were H&E stained and the right two columns with Safranin-O. For each staining, the images of the right column are magnified from the left column. The capillary infiltration areas were indicated with black arrows. All scale bars represent 200 µm.</p
Oxidative Degradation of Thermosets Based on Thioketal Cleavable Linkages in Aqueous Environment
Thermosets
are rigid, infusible, and unmolded materials containing
three-dimensional (3D) cross-linked structures. They are considered
a fundamental pillar in the international economy, which are produced
by 65 million tons annually. The responsive cross-linking moieties
provide the thermosets characterized with outstanding physicochemical
properties such as stiffness, degradability, and chemical and thermal
resistance. We prepared degradable thermoset materials using thioketal
(TK) cross-linkers, which underwent main-chain or side change degradation
in the presence of hydrogen peroxide in water. TK cross-linkers at
different concentrations (5, 10, and 20% wt %) were polymerized with
2-hydroxyethyl acrylate (HEA) or with 2-hydroxyethyl methacrylate
(HEMA) and 1-vinyl-2-pyrrolidone (PD) to produce cross-linked poly(HEA)
and poly(HEMA-PD) by free radical polymerization, respectively. The
resultant polymer materials completely degraded in hydrogen peroxide/water
(3–30%, vol). Using isophorone diisocyanate, we also produced
degradable polyurethane based on TK-bearing diol. We prepared a 3D
degradable thermoset using the Direct-Ink-Writing (DIW) 3D printing
technology, which was charged by diethylene glycol diacrylate (15%,
wt %) and a prepolymer (isophorone diisocyanate terminated by acrylate
moieties) containing diol-thioketal linkage (15%, wt %). Finally,
we found that TK-poly(HEA) underwent microbial degradation by Lactobacillus jensenii at 37 °C, which indicates
a benign eco-friendly effect
Concentrations of GFs in peripheral blood and PRP.
<p>Concentrations of GFs in peripheral blood and PRP.</p
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