In diabetes mellitus, the polyol pathway is highly active and consumes approximately 30% glucose in the body. This pathway contains 2 reactions catalyzed by aldose reductase (AR) and sorbitol ...dehydrogenase, respectively. AR reduces glucose to sorbitol at the expense of NADPH, while sorbitol dehydrogenase converts sorbitol to fructose at the expense of NAD+, leading to NADH production. Consumption of NADPH, accumulation of sorbitol, and generation of fructose and NADH have all been implicated in the pathogenesis of diabetes and its complications. In this review, the roles of this pathway in NADH/NAD+ redox imbalance stress and oxidative stress in diabetes are highlighted. A potential intervention using nicotinamide riboside to restore redox balance as an approach to fighting diabetes is also discussed.
2D perovskites are recently attracting a significant amount of attention, mainly due to their improved stability compared with their 3D counterpart, e.g., the archetypical MAPbI3. Interestingly, the ...first studies on 2D perovskites can be dated back to the 1980s. The most popular 2D perovskites have a general formula of (RNH3)2MAn−1MnX3n+1, where n represents the number of metal halide octahedrons between the insulating organic cation layers. The optoelectronic properties of 2D perovskites, e.g., band gap, are highly dependent on the thickness of the inorganic layers (i.e., the value of n). Herein, 2D perovskites are arbitrarily divided into three classes, strict 2D (n = 1), quasi‐2D (n = 2–5), and quasi‐3D (n > 5), and research progress is summarized following this classification. The majority of existing 2D perovskites only employ very simple organic cations (e.g., butyl ammonium or phenylethyl ammonium), which merely function as the supporting layer/insulating barrier to achieve the 2D structure. Thus, a particularly important research question is: can functional organic cations be designed for these 2D perovskites, where these functional organic cations would play an important role in dictating the optoelectronic properties of these organic–inorganic hybrid materials, leading to unique device performance or applications?
Two‐dimensional perovskites typically have a general formula of (RNH3)2MAn−1MnX3n+1, and can be arbitrarily categorized into strict 2D (n = 1), quasi‐2D (n = 2−5), and quasi‐3D (n > 5). Research progress in each category is summarized, and it is proposed that designing functional organics to manipulate the optoelectronic properties of 2D perovskites can lead to unique device applications.
Abstract
Mixing has been widely used in the interpretation of radiogenic isotope ratios and highly incompatible trace element variations in basalts produced by melting of a heterogeneous mantle. The ...binary mixing model is constructed by considering mass balance of endmember components, which is independent of physical state and spatial distribution of the endmembers in the mantle source. Variations of radiogenic isotope ratios and highly incompatible trace elements in basalts also depend on the size and spatial distribution of chemical and lithological heterogeneities in the mantle source. Here we present a new mixing model and a mixing scheme that take into account of the size, spatial location, and melting history of enriched mantle (EM) and depleted mantle (DM) parcels in the melting column. We show how Sr, Nd, and Hf concentrations and isotope ratios in the aggregated or pooled melt collected at the top of the melting column vary as a function of location of the EM parcel in the melting column. With changing location of the EM parcel in the upwelling melting column, compositions of the pooled melt do not follow a single mixing curve expected by the binary mixing model. Instead, they define a mixing loop that has an enriched branch and a depleted branch joined by two extreme points in composition space. The origin of the mixing loop can be traced back to four types of EM distribution or configuration in the melting column. The shape of the mixing loop depends on the relative melting rate of the EM to that of the DM and the number and spacing of EM parcels in the melting column. Probabilities of sampling the enriched and depleted branches in the pooled melt are proportional to volume fractions of the enriched and depleted materials in the mantle source. Mixing of pooled melts from a bundle of melting columns results in mixing envelopes in the isotope ratio correlation diagrams. The mixing envelope is a useful tool for studying chemical variations in mantle-derived melts. As an application, we consider scattered correlations in 87Sr/86Sr vs. 143Nd/144Nd and 143Nd/144Nd vs. 176Hf/177Hf in mid-ocean ridge basalts. We show that such correlations arise naturally from melting of a spatially heterogeneous mantle.
Reactive species produced in the cell during normal cellular metabolism can chemically react with cellular biomolecules such as nucleic acids, proteins, and lipids, thereby causing their oxidative ...modifications leading to alterations in their compositions and potential damage to their cellular activities. Fortunately, cells have evolved several antioxidant defense mechanisms (as metabolites, vitamins, and enzymes) to neutralize or mitigate the harmful effect of reactive species and/or their byproducts. Any perturbation in the balance in the level of antioxidants and the reactive species results in a physiological condition called “oxidative stress.” A catalase is one of the crucial antioxidant enzymes that mitigates oxidative stress to a considerable extent by destroying cellular hydrogen peroxide to produce water and oxygen. Deficiency or malfunction of catalase is postulated to be related to the pathogenesis of many age-associated degenerative diseases like diabetes mellitus, hypertension, anemia, vitiligo, Alzheimer’s disease, Parkinson’s disease, bipolar disorder, cancer, and schizophrenia. Therefore, efforts are being undertaken in many laboratories to explore its use as a potential drug for the treatment of such diseases. This paper describes the direct and indirect involvement of deficiency and/or modification of catalase in the pathogenesis of some important diseases such as diabetes mellitus, Alzheimer’s disease, Parkinson’s disease, vitiligo, and acatalasemia. Details on the efforts exploring the potential treatment of these diseases using a catalase as a protein therapeutic agent have also been described.
Exploring highly efficient, stable, and non-noble-metal bifunctional electrocatalysts for overall water splitting is greatly desired but still remains an ongoing challenge. Transition metal ...phosphides (TMPs) have been utilized as promising bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), but practical implementation is impeded by the low electronic conductivity and poor chemical stability of TMPs. Recently, a new class of 2D materials, MXenes, have attracted significant attention for diverse energy-related applications. Here, a general approach is reported to synthesize TMPs, including CoP, Ni
2
P, FeP, and Cu
3
P nanoarrays, on Ti
3
C
2
MXene nanosheets through topotactic transformations from transition metal layered double hydroxide (LDH) precursors. The Ti
3
C
2
MXene in the CoP/Ti
3
C
2
MXene heterostructure acts as a highly conductive substrate which not only facilitates rapid electron transfer at the heterointerface, but also prevents the TMP nanoarrays from aggregation. Meanwhile, TMP nanoarrays prevent MXene nanosheets from restacking and contribute remarkable activity and long-term stability. Particularly, the strong interactions between CoP and the Ti
3
C
2
MXene endow the CoP/Ti
3
C
2
MXene heterostructure with exceptional catalytic activities and stability toward the HER at all pH values. Moreover, the CoP/Ti
3
C
2
MXene also exhibited superior OER performance in alkaline electrolyte. Consequently, the CoP/Ti
3
C
2
MXene even outperforms the commercial Pt/C|IrO
2
couple for overall water splitting under alkaline conditions. The experimental results reveal that the strong electronic coupling effect at the heterointerface can efficiently accelerate the HER/OER kinetics. This study opens up opportunities to rational design of advanced electrocatalysts for diverse applications by using the MXene family as the underlying support coupled with various active components.
Exploring highly efficient, stable, and non-noble-metal bifunctional electrocatalysts for overall water splitting is greatly desired but still remains an ongoing challenge.
In July 2023, the American Heart Association (AHA), the American College of Cardiology (ACC), and four other professional societies jointly released the updated version of the ...AHA/ACC/ACCP/ASPC/NLA/PCNA Guidelines for the Management of Patients with Chronic Coronary Artery Disease. This guideline emphasizes a patient-centered and team-based approach to the overall management of chronic coronary artery disease (CCD), highlights the impact of lifestyle improvements on the prognosis of CCD patients, and provides new insights into risk assessment for major adverse cardiovascular events (MACE) and recommendations for novel medications. These updates hold significant guiding value for health care professionals in China to provide high-quality management for CCD patients.
The extensive research of graphene and its derivatives in biomedical applications during the past few years has witnessed its significance in the field of nanomedicine. Starting from simple drug ...delivery systems, the application of graphene and its derivatives has been extended to a versatile platform of multiple therapeutic modalities, including photothermal therapy, photodynamic therapy, magnetic hyperthermia therapy, and sonodynamic therapy. In addition to monotherapy, graphene‐based materials are widely applied in combined therapies for enhanced anticancer activity and reduced side effects. In particular, graphene‐based materials are often designed and fabricated as “smart” platforms for stimuli‐responsive nanocarriers, whose therapeutic effects can be activated by the tumor microenvironment, such as acidic pH and elevated glutathione (termed as “endogenous stimuli”), or light, magnetic, or ultrasonic stimuli (termed as “exogenous stimuli”). Herein, the recent advances of smart graphene platforms for combined therapy applications are presented, starting with the principle for the design of graphene‐based smart platforms in combined therapy applications. Next, recent advances of combined therapies contributed by graphene‐based materials, including chemotherapy‐based, photothermal‐therapy‐based, and ultrasound‐therapy‐based synergistic therapy, are outlined. In addition, current challenges and future prospects regarding this promising field are discussed.
The recent advances of smart graphene platforms for combined therapy applications are reviewed, starting with the principle for the design of graphene‐based smart platforms in combined therapy applications. Recent advances of synergistic therapies contributed by graphene‐based materials are outlined and current challenges and future prospects regarding this promising field are discussed.
Recently LHCb declared a new structure
X
(6900) in the final state di-
J
/
ψ
which is popularly regarded as a
cc
-
c
¯
c
¯
tetraquark state. Within the Bethe–Salpeter (B–S) framework we study the ...possible
cc
-
c
¯
c
¯
bound states and the interaction between diquark (
cc
) and antidiquark (
c
¯
c
¯
). In this work
cc
(
c
¯
c
¯
) is treated as a color anti-triplet (triplet) axial-vector so the quantum numbers of
cc
-
c
¯
c
¯
bound state are
0
+
,
1
+
and
2
+
. Learning from the interaction in meson case and using the effective coupling we suggest the interaction kernel for the diquark and antidiquark system. Then we deduce the B–S equations for different quantum numbers. Solving these equations numerically we find the spectra of some excited states can be close to the mass of
X
(6900) when we assign appropriate values for parameter
κ
introduced in the interaction (kernel). We also briefly calculate the spectra of
bb
-
b
¯
b
¯
bound states. Future measurement of
bb
-
b
¯
b
¯
state will help us to determine the exact form of effective interaction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Multivalent cooperativity plays an important role in the supramolecular self-assembly process. Herein, we report a remarkable cooperative enhancement of both structural integrity and metal ion ...selectivity on metal-organic M
L
tetrahedral cages self-assembled from a tris-tridentate ligand (L
) with a variety of metal ions spanning across the periodic table, including alkaline earth (Ca
), transition (Cd
), and all the lanthanide (Ln
) metal ions. All these M
L
cages are stable to excess metal ions and ligands, which is in sharp contrast with the tridentate (L
) ligand and bis-tridentate (L
) ligand bearing the same coordination motif as L
. Moreover, high-precision metal ion self-sorting is observed during the mixed-metal self-assembly of tetrahedral M
L
cages, but not on the M
L
counterparts. Based on the strong cooperative metal ion self-recognition behavior of M
L
cages, a supramolecular approach to lanthanide separation is demonstrated, offering a new design principle of next-generation extractants for highly efficient lanthanide separation.
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