24 research outputs found
C–H Bond Functionalization via [1,5]-Hydride Shift/Cyclization Sequence: Approach to Spiroindolenines
A concise synthesis
of spiroindolenines from 2-substituted (Me,
Et) indoles and 2-(pyrrolidin-1-yl)benzaldehydes has been developed
via a [1,5]-hydride shift/cyclization sequence. This method features
a wide substrate scope and an operationally simple procedure, affording
the spiroindolenines in good to excellent yields and moderate diastereoselectivity
(3.5/1 dr). When the inseparable mixture of spiroindolenine isomers
were washed with isopropyl ether after flash chromatography, the major
isomers could be obtained in up to >20/1 dr
Stereoselective Synthesis of Arylglycine Derivatives via Palladium-Catalyzed α‑Arylation of a Chiral Nickel(II) Glycinate
A practical and efficient stereoselective
synthesis of arylglycine
derivatives was realized via palladium-catalyzed α-arylation
of a chiral nickel(II) glycinate complex with aryl bromides. The structurally
diverse arylglycine products were obtained in excellent isolated yields
and with good diastereoselectivity. A simple acidic hydrolysis furnished
optically pure arylglycines in high yield, and the chiral ligand (S)-BPB
could be efficiently recovered and reused
Nanosheet-Assembled ZnFe<sub>2</sub>O<sub>4</sub> Hollow Microspheres for High-Sensitive Acetone Sensor
Semiconductor oxides with hierarchically
hollow architecture can provide significant advantages as sensing
materials for gas sensors by facilitating the diffusion of target
gases. Herein, we develop a facile template-free solvothermal strategy
combined with the subsequent thermal treatment process toward the
successful synthesis of novel ZnFe<sub>2</sub>O<sub>4</sub> hollow
flower-like microspheres. The images of electron microscopy unambiguously
indicated that the ZnFe<sub>2</sub>O<sub>4</sub> nanosheets with thickness
of around 20 nm assembled hierarchically to form the unique flower-like
architecture. As a proof-of-concept demonstration of the function,
the as-prepared product was utilized as sensing material for gas sensor.
Significantly, in virtue of the porous shell structure, hollow interior,
and large surface area, ZnFe<sub>2</sub>O<sub>4</sub> hierarchical
microspheres exhibited high response, excellent cyclability, and long-term
stability to acetone at the operating temperature of 215 °C
Synthesis and Molecular Structures of BINOL Complexes: An STM Investigation of 2D Self-Assembly
Three new (R)-BINOL complexes have
been prepared. 2D self-assembly
has been observed in the system consisting of crystalline (R)-BINOL
derivatives (guest) and 1,3,5-tris(10-carboxydecyloxy)-benzene (host)
by means of the scanning tunneling microscopy (STM) technique. Density
functional theory (DFT) calculations help to reveal the assembly on
the HOPG surface
Construction of Oxadiazepines via Lewis Acid-Catalyzed Tandem 1,5-Hydride Shift/Cyclization
Expeditious access to oxadiazepines
via 1,5-hydride shift/cyclization
of pyrrolidine- or tetrahydroisoquinoline-containing nitrones has
been developed. With 1,3-dipole nitrones serving as the hydride acceptors,
this transformation was promoted by a Lewis acid, providing access
to structurally diverse oxadiazepines in good yields. A one-pot process
for in situ nitrone formation, a 1,5-hydride shift, and ring cyclization
was also realized
A Collaborative Assembly Strategy for Tumor-Targeted siRNA Delivery
A novel
“collaborative assembly” approach was reported
for the synthesis of an siRNA delivery system via a combination of
an electrostatically driven physical assembly and a facile click reaction-mediated
chemical assembly, which showed various advantages of more safety,
efficiency, and flexibility over the conventional approach that is
only based on the physical assembly. This strategy remained a high
cationic property of lipid-based complex for high siRNA loading capacity.
The direct chemical modification of a model polyanion, hyaluronic
acid (HA) on the cationic complex via click chemistry shielded the
positive charge of complex without affecting the siRNA binding, which
reduced the toxicity and enhanced the blood stability of the complex.
In addition, the incorporated polyanion might be prefunctionalized,
which endued the carrier with better biological characteristics such
as long circulating or tumor targeting. We demonstrated that the obtained
lipid-polymer hybrid nanoparticle (RSC-HA) using collaborative assembly
presented greater <i>in vivo</i> stability in the blood
for efficient tumor targeting than the physically assembled RSC/HA
in which HA was physically adsorbed on the complex. After endocytosis
into the cells, the protection of RSC-HA on siRNA turned off, while
the release of siRNA induced by the intracellular signals for enhanced
gene-silencing capacity. This combination of physical and chemical
assemblies provides an efficient strategy for the exploitation of
safe, stable, and functionalized siRNA delivery systems
Mean z-score matrices for the control and PNE groups.
<p>Each figure shows a 116×116 square matrix in which the x- and y-axes correspond to AAL regions. Each entry indicates the mean z-score representing functional connectivity between each pair of regions in the brain.</p
Design and Synthesis of Curcumin Analogues for in Vivo Fluorescence Imaging and Inhibiting Copper-Induced Cross-Linking of Amyloid Beta Species in Alzheimer’s Disease
In
this article, we first designed and synthesized curcumin-based
near-infrared (NIR) fluorescence imaging probes for detecting both
soluble and insoluble amyloid beta (Aβ) species and then an
inhibitor that could attenuate cross-linking of Aβ induced by
copper. According to our previous results and the possible structural
stereohindrance compatibility of the Aβ peptide and the hydrophobic/hydrophilic
property of the Aβ13–20 (HHQKLVFF) fragment, NIR imaging
probe CRANAD-58 was designed and synthesized. As expected CRANAD-58
showed significant fluorescence property changes upon mixing with
both soluble and insoluble Aβ species in vitro. In vivo NIR
imaging revealed that CRANAD-58 was capable of differentiating transgenic
and wild-type mice as young as 4 months old, the age that lacks apparently
visible Aβ plaques and Aβ is likely in its soluble forms.
According to our limited studies on the interaction mechanism between
CRANAD-58 and Aβ, we also designed CRANAD-17 to attenuate the
cross-linking of Aβ42 induced by copper. It is well-known that
the coordination of copper with imidazoles on Histidine-13 and 14
(H13, H14) of Aβ peptides could initialize covalent cross-linking
of Aβ. In CRANAD-17, a curcumin scaffold was used as an anchoring
moiety to usher the designed compound to the vicinity of H13 and H14
of Aβ, and imidazole rings were incorporated to compete with
H13/H14 for copper binding. The results of SDS-PAGE gel and Western
blot indicated that CRANAD-17 was capable of inhibiting Aβ42
cross-linking induced by copper. This raises a potential for CRANAD-17
to be considered for AD therapy
DataSheet_1_Deep learning based on 68Ga-PSMA-11 PET/CT for predicting pathological upgrading in patients with prostate cancer.docx
ObjectivesTo explore the feasibility and importance of deep learning (DL) based on 68Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT in predicting pathological upgrading from biopsy to radical prostatectomy (RP) in patients with prostate cancer (PCa).MethodsIn this retrospective study, all patients underwent 68Ga-PSMA-11 PET/CT, transrectal ultrasound (TRUS)-guided systematic biopsy, and RP for PCa sequentially between January 2017 and December 2022. Two DL models (three-dimensional [3D] ResNet-18 and 3D DenseNet-121) based on 68Ga-PSMA-11 PET and support vector machine (SVM) models integrating clinical data with DL signature were constructed. The model performance was evaluated using area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity.ResultsOf 109 patients, 87 (44 upgrading, 43 non-upgrading) were included in the training set and 22 (11 upgrading, 11 non-upgrading) in the test set. The combined SVM model, incorporating clinical features and signature of 3D ResNet-18 model, demonstrated satisfactory prediction in the test set with an AUC value of 0.628 (95% confidence interval [CI]: 0.365, 0.891) and accuracy of 0.727 (95% CI: 0.498, 0.893).ConclusionA DL method based on 68Ga-PSMA-11 PET may have a role in predicting pathological upgrading from biopsy to RP in patients with PCa.</p