Organocatalytic Enantioselective Synthesis of Polysubstituted Spirooxindoles using a Tandem Michael–Michael Reaction

A highly efficient stereoselective method for the synthesis of functionalized spirooxindole derivatives with four contiguous stereogenic centers, including two adjacent quaternary stereogenic centers, was realized through an organocatalytic tandem Michael–Michael reaction. By employing a quinidine‐derived thiourea organocatalyst, the reaction between (E)‐2‐cyano‐2‐(2‐oxo‐1‐tritylindolin‐3‐ylidene)acetates and (E)‐1‐alkyl‐6‐nitro‐hex‐2‐en‐1‐ones yields the desired spirooxindole products in good yields (up to 90%) and with excellent stereoselectivities (up to 95:5 dr and 98% ee).

     

Stabilizing nanocrystalline Cu2O with ZnO/rGO: Engineered photoelectrodes enables efficient water splitting

The engineered photoelectrodes have received significant attention in the photoelectrochemical (PEC) applications. Herein, we prepared a highly effective photoelectrode based on Cu₂O decorated with ZnO and rGO for efficient PEC water splitting. Firstly, different thickness Cu₂O is sputtered on the FTO substrate (FC). The PEC performance of the FC photoelectrode further improved by depositing the ZnO and rGO protection layers (FCZG). The fabricated photoelectrodes are systematically investigated for their morphological and crystal structure by AFM, FESEM, TEM, XPS, XRD, and RAMAN, UVDRS, and PL analysis. The FCZG hybrid photoelectrode exhibit a photocurrent density of 4.94 mA cm^?2 at 0 V vs. reversible hydrogen electrode (RHE), which is 1.5 times higher than the unmodified photoelectrodes. The improved PEC performance of the FCZG hybrid photoelectrode is due to the high surface roughness, larger electrochemical active surface area, and less radiative recombination rate of the photogenerated charge carriers.     

Hierarchically self-assembled ZnO architectures: Establishing light trapping networks for effective photoelectrochemical water splitting

Here we develop photoanodes based on hierarchical zinc oxide (ZnO) nanostructures such as vertically aligned nanorods (NR), nanorods interconnected by thin nanosheets (NR@TN) and nanorods interconnected by dense nanosheets (NR@DN). The morphological variations were successfully controlled by secondary growth time and the plausible formation mechanisms of these hierarchical ZnO architectures were explained based on the experiment analysis. Under simulated light illumination (AM 1.5, 100 mW cm^?2), NR@TN produced a photocurrent density of 0.62 mA/cm² at 1.23 V vs. reversible hydrogen electrode (vs. RHE). Importantly, 35% enrichment in photoconversion efficiency was observed for NR@TN at much lower bias potential (0.77 V vs. RHE) compared with NR (0.135%) and NR@DN (0.13% at 0.82 V vs. RHE). Key to the improved performance is believed to be synergetic effects of excellent light-trapping characteristics and the large surface-to-volume ratios due to the nanosheet structures. The nanorod connected with thin nanosheet structures improved the efficiency by means of improved charge transfer across the nanostructure/electrolyte interfaces, and efficient charge transport within the material. We believe that the hierarchical ZnO structures can be used in conjunction with doping and/or sensitization to promote the photoelectrochemical (PEC) performance. Further, the ZnO nanorod interconnected with nanosheets morphology presented in this article is extendable to other metal oxide semiconductors to establish a universal protocol for the development of high performance photoanodes in the field of PEC water splitting.     

Dendritic Cells Pulsed with Cytokine-Adjuvanted Tumor Membrane Vesicles Inhibit Tumor Growth in HER2-Positive and Triple Negative Breast Cancer Models

Dendritic cells (DCs) are the most effective antigen presenting cells for the development of T cell responses. The only FDA approved DC-based immunotherapy to date is Sipuleucel-T, which utilizes a fusion protein to stimulate DCs ex vivo with GM-CSF and simultaneously deliver the antigen PAP for prostate cancer. This approach is restricted by the breadth of immunity elicited to a single antigen, and to cancers that have a defined tumor associated antigen. Other multi-antigen approaches have been restricted by poor efficacy of vaccine adjuvants. We have developed a vaccine platform that consists of autologous DCs pulsed with cytokine-adjuvanted tumor membrane vesicles (TMVs) made from tumor tissue, that encapsulate the antigenic landscape of individual tumors. Here we test the efficacy of DCs pulsed with TMVs incorporated with glycolipid-anchored immunostimulatory molecules (GPI-ISMs) in HER2-positive and triple negative breast cancer murine models. Pulsing of DCs with TMVs containing GPI-ISMs results in superior uptake of vesicles, DC activation and cytokine production. Adaptive transfer of TMV-pulsed DCs to tumor bearing mice results in the inhibition of tumor growth, reduction in lung metastasis, and an increase in immune cell infiltration into the tumors. These observations suggest that DCs pulsed with TMVs containing GPI-GM-CSF and GPI-IL-12 can be further developed to be used as a personalized immunotherapy platform for cancer treatment.     

Homologous CoP/NiCoP Heterostructure on N‐Doped Carbon for Highly Efficient and pH‐Universal Hydrogen Evolution Electrocatalysis

Hydrogen evolution electrocatalysts can achieve sustainable hydrogen production via electrocatalytic water splitting; however, designing highly active and stable noble‐metal‐free hydrogen evolution electrocatalysts that perform as efficiently as Pt catalysts over a wide pH range is a challenging task. Herein, a new 2D cobalt phosphide/nickelcobalt phosphide (CoP/NiCoP) hybrid nanosheet network is proposed, supported on an N‐doped carbon (NC) matrix as a highly efficient and durable pH‐universal hydrogen evolution reaction (HER) electrocatalyst. It is derived from topological transformation of corresponding layer double hydroxides and graphitic carbon nitride. This 2D CoP/NiCoP/NC catalyst exhibits versatile HER electroactivity with very low overpotentials of 75, 60, and 123 mV in 1 m KOH, 0.5 m H₂SO₄, and 1 m PBS electrolytes, respectively, delivering a current density of 10 mA cm^?2 for HER. Such impressive HER performance of the hybrid electrocatalyst is mainly attributed to the collective effects of electronic structure engineering, strong interfacial coupling between CoP and NiCoP in heterojunction, an enlarged surface area/exposed catalytic active sites due to the 2D morphology, and conductive NC support. This method is believed to provide a basis for the development of efficient 2D electrode materials with various electrochemical applications.     

Heterogeneity of cardiac allograft vasculopathy: clinical insights from coronary angioscopy

OBJECTIVES: With this study, we sought to examine the heterogeneity of cardiac allograft vasculopathy in vivo using coronary angioscopy as an adjunct to intravascular ultrasound, and we evaluated the clinical relations of immunologic and nonimmunologic risk factors with the different forms of cardiac allograft vasculopathy detected angioscopically. BACKGROUND: Intravascular ultrasound detects vascular intimal proliferation accurately but is limited in its ability to delineate morphologic characteristics. Coronary angioscopy can evaluate intimal surface morphology by direct visualization and can differentiate pathologically distinct forms of plaque topography on the basis of color and contour. METHODS: We studied 107 consecutive heart transplant recipients with intravascular ultrasound and angioscopy at the time of their annual angiogram, and we assessed the relation of nonimmunologic and immunologic risk factors to the development of cardiac allograft vasculopathy distinguished angioscopically into a pigmented (yellow) or nonpigmented (white) intimal thickening. We further evaluated the clinical differences in cardiac events among these two forms of angioscopically heterogeneous forms of cardiac allograft vasculopathy. RESULTS: Significant clinical predictors of nonpigmented intimal thickening were advanced donor age and lower mean cyclosporine levels, whereas hyperlipidemia, cumulative prednisone dose and time since transplantation correlated with pigmented intimal hyperplasia. In addition, comparisons between the two angioscopic groups revealed increased intimal thickening, serum cholesterol, low density lipoprotein cholesterol, acute allograft rejection and time since transplantation in the group with pigmented intimal thickening (p < 0.05). With regard to cardiac events, nonpigmented plaque was more frequently found in the sudden death group (53% vs. 20%, p = 0.05), whereas the nonsudden cardiac event group had a significantly higher prevalence of pigmented plaque (80% vs. 47%, p = 0.07). CONCLUSIONS: These findings indicate that cardiac allograft vasculopathy is a heterogeneous disease with varied morphologic expressions with different clinical implications. Furthermore, this investigation provides insight into the cohesive, yet diverse influences of various factors, particularly immunosuppression, in these forms of cardiac allograft vasculopathy.     

Geometric and Electronic Structural Engineering of Isolated Ni Single Atoms for a Highly Efficient CO2 Electroreduction

Tuning the coordination environment and geometric structures of single atom catalysts is an effective approach for regulating the reaction mechanism and maximize the catalytic efficiency of single-atom centers. Here, a template-based synthesis strategy is proposed for the synthesis of high-density NiN_x sites anchored on the surface of hierarchically porous nitrogen-doped carbon nanofibers (Ni-HPNCFs) with different coordination environments. First-principles calculations and advanced characterization techniques demonstrate that the single Ni atom is strongly coordinated with both pyrrolic and pyridinic N dopants, and that the predominant sites are stabilized by NiN₃ sites. This dual engineering strategy increases the number of active sites and utilization efficiency of each single atom as well as boosts the intrinsic activity of each active site on a single-atom scale. Notably, the Ni-HPNCF catalyst achieves a high CO Faradaic efficiency (FE_CO) of 97% at a potential of −0.7 V, a high CO partial current density (j_CO) of 49.6 mA cm⁻² (−1.0 V), and a remarkable turnover frequency of 24 900 h⁻¹ (−1.0 V) for CO₂ reduction reactions (CO₂RR). Density functional theory calculations show that compared to pyridinic-type NiN_x, the pyrrolic-type NiN₃ moieties display a superior CO₂RR activity over hydrogen evolution reactions, resulting in their superior catalytic activity and selectivity.     

The Jacalin-Related Lectin HvHorcH Is Involved in the Physiological Response of Barley Roots to Salt Stress

Salt stress tolerance of crop plants is a trait with increasing value for future food production. In an attempt to identify proteins that participate in the salt stress response of barley, we have used a cDNA library from salt-stressed seedling roots of the relatively salt-stress-tolerant cv. Morex for the transfection of a salt-stress-sensitive yeast strain (Saccharomyces cerevisiae YSH818 Δhog1 mutant). From the retrieved cDNA sequences conferring salt tolerance to the yeast mutant, eleven contained the coding sequence of a jacalin-related lectin (JRL) that shows homology to the previously identified JRL horcolin from barley coleoptiles that we therefore named the gene HvHorcH. The detection of HvHorcH protein in root extracellular fluid suggests a secretion under stress conditions. Furthermore, HvHorcH exhibited specificity towards mannose. Protein abundance of HvHorcH in roots of salt-sensitive or salt-tolerant barley cultivars were not trait-specific to salinity treatment, but protein levels increased in response to the treatment, particularly in the root tip. Expression of HvHorcH in Arabidopsis thaliana root tips increased salt tolerance. Hence, we conclude that this protein is involved in the adaptation of plants to salinity.