Atomic Au3Cu Palisade Interlayer in Core@Shell Nanostructures for Efficient Kirkendall Effect Mediation.

Plasmonic Cu@semiconductor heteronanocrystals (HNCs) have many favorable properties, but the synthesis of solid structures is often hindered by the nanoscale Kirkendall effect. Herein, we present the use of an atomically thin Au3Cu palisade interlayer to reduce lattice mismatch and mediate the Kirkendall effect, enabling the successive topological synthesis of Cu@Au3Cu@Ag, Cu@Au3Cu@Ag2S, and further transformed solid Cu@Au3Cu@CdS core-shell HNCs via cation exchange. The atomically thin and intact Au3Cu palisade interlayer effectively modulates the diffusion kinetics of Cu atoms as demonstrated by experimental and theoretical investigations and simultaneously alleviates the lattice mismatch between Cu and Ag as well as Cu and CdS. The Cu@Au3Cu@CdS HNCs feature exceptional crystallinity and atomically organized heterointerfaces between the plasmonic metal and the semiconductor. This results in the efficient plasmon-induced injection of hot electrons from Cu@Au3Cu into the CdS shell, enabling the Cu@Au3Cu@CdS HNCs to achieve high activity and selectivity for the photocatalytic reduction of CO2 to CO.

In Situ Single Particle Reconstruction Reveals 3D Evolution of PtNi Nanocatalysts During Heating.

Tailoring nanoparticles' composition and morphology is of particular interest for improving their performance for catalysis. A challenge of this approach is that the nanoparticles' optimized initial structure often changes during use. Visualizing the three dimensional (3D) structural transformation in situ is therefore critical, but often prohibitively difficult experimentally. Although electron tomography provides opportunities for 3D imaging, restrictions in the tilt range of in situ holders together with electron dose considerations limit the possibilities for in situ electron tomography studies. Here, an in situ 3D imaging methodology is presented using single particle reconstruction (SPR) that allows 3D reconstruction of nanoparticles with controlled electron dose and without tilting the microscope stage. This in situ SPR methodology is employed to investigate the restructuring and elemental redistribution within a population of PtNi nanoparticles at elevated temperatures. The atomic structure of PtNi is further examined and a heat-induced transition is found from a disordered to an ordered phase. Changes in structure and elemental distribution are linked to a loss of catalytic activity in the oxygen reduction reaction. The in situ SPR methodology employed here can be extended to a wide range of in situ studies employing not only heating, but gaseous, aqueous, or electrochemical environments to reveal in-operando nanoparticle evolution in 3D.

Synthesis of Quillaic Acid through Sustainable C-H Bond Activations.

To meet the demand for quillaic acid, a multigram synthesis of quillaic acid was accomplished in 14 steps, starting from oleanolic acid, leading to an overall yield of 3.4%. Key features include C-H activation at C-16 and C-23. Through Pd-catalyzed C-H acetoxylation, the oxidation at C-23 was observed as the major product, as opposed to at C-24. A copper-mediated C-H hydroxylation using O2 successfully afforded the single isomer, 16ß-ol triterpenoid, followed by configuration inversion to the desired 16α-ol compound. In summary, with steps optimized and conducted on a multigram scale, quillaic acid could be feasibly acquired through C-H activation with inexpensive copper catalysts, promoting a more sustainable approach.

Modulations of ocean-atmosphere interactions on squid abundance over Southwest Atlantic.

Anthropogenic shifts in seas are reshaping fishing trends, with significant implications for aquatic food sources throughout this century. Examining a 21-year abundance dataset of Argentine shortfin squids Illex argentinus paired with a regional oceanic analysis, we noted strong correlations between squid annual abundance and sea surface temperature (SST) in January and February and eddy kinetic energy (EKE) from March to May in the Southwest Atlantic. A deeper analysis revealed combined ocean-atmosphere interactions, pinpointed as the primary mode in a rotated empirical orthogonal function analysis of SST. This pattern produced colder SST and amplified EKE in the surrounding seas, factors crucial for the unique life stages of squids. Future projections from the CMIP6 archive indicated that this ocean-atmosphere pattern, referred to as the Atlantic symmetric pattern, would persist in its cold SST phase, promoting increased squid abundance. However, rising SSTs due to global warming might counteract the abundance gains. Our findings uncover a previously unrecognized link between squids and specific environmental conditions governed by broader ocean-atmosphere interactions in the Southwest Atlantic. Integrating these insights with seasonal and decadal projections can offer invaluable information to stakeholders in squid fisheries and marine conservation under a changing climate.

Toward an Improved Triterpene 3-O-Glucuronidation: The Systematic Determination of the Relative Reactivities of Glucuronyl Donors and Acceptors.

3-O-ß-Glucuronide triterpenes are plant-derived compounds. Some of them have been used as herbal medicine and in pharmaceuticals, such as chikusetsu saponins and Quillaja saponins. However, the demand for these materials has remained largely a challenge owing to their natural scarcity and low-yielding purification process. Therefore, a chemical triterpene 3-O-glucuronidation was conducted in this study to alleviate the surging demand on natural source. Various glucuronyl imidate donors and oleanane-type triterpene acceptors were synthesized, and the relative reactivity values (RRV) and acceptor nucleophilic constants (Aka) were systematically measured to study their influence on glucuronidation yield. As a result, applying donors in higher RRV value generally improved the production of 3-O-glucuronide triterpenes. Meanwhile, a bulky pivaloyl group was an ideal 2-O-protection to provide ß-selectivity and prevented side reactions, including orthoester formation and acyl-transfer reaction. Collectively, a positive correlation was observed between reactive donors/acceptors and improved glucuronidation yields. These findings offered insights on the influence of donors' and acceptors' reactivities on 3-O-ß-glucuronide triterpenes synthesis, and this knowledge would help to access saponins of interest to address future needs.

Ion exchange in atomically thin clays and micas.

The physical properties of clays and micas can be controlled by exchanging ions in the crystal lattice. Atomically thin materials can have superior properties in a range of membrane applications, yet the ion-exchange process itself remains largely unexplored in few-layer crystals. Here we use atomic-resolution scanning transmission electron microscopy to study the dynamics of ion exchange and reveal individual ion binding sites in atomically thin and artificially restacked clays and micas. We find that the ion diffusion coefficient for the interlayer space of atomically thin samples is up to 104 times larger than in bulk crystals and approaches its value in free water. Samples where no bulk exchange is expected display fast exchange at restacked interfaces, where the exchanged ions arrange in islands with dimensions controlled by the moiré superlattice dimensions. We attribute the fast ion diffusion to enhanced interlayer expandability resulting from weaker interlayer binding forces in both atomically thin and restacked materials. This work provides atomic scale insights into ion diffusion in highly confined spaces and suggests strategies to design exfoliated clay membranes with enhanced performance.

Telluride Nanocrystals with Adjustable Amorphous Shell Thickness and Core-Shell Structure Modulation by Aqueous Cation Exchange.

Engineering the structure of core-shell colloidal semiconductor nanoparticles (CSNPs) is attractive due to the potential to enhance photo-induced charge transfer and induce favorable optical and electronic properties. Nonetheless, the sensitivity of telluride CSNPs to high temperatures makes it challenging to precisely modulate their surface crystallinity. Herein, we have developed an efficient strategy for synthesizing telluride CSNPs with thin amorphous shells using aqueous cation exchange (ACE). By changing the synthesis temperature in the range of 40-110 °C, the crystallinity of the CdTe nanoparticles was controllable from perfect crystals with no detectable amorphous shell (c-CdTe) to a core-shell structure with a crystalline CdTe NP core covered by an amorphous shell of tunable thickness up to 7-8 nm (c@a-CdTe). A second ACE step transformed c@a-CdTe to crystalline CdTe@HgTe core-shell NPs. The c@a-CdTe nanoparticles synthesized at 60 °C and having a 4-5 nm thick amorphous shell exhibited the highest surface-enhanced Raman scattering activity with a high enhancement factor around 8.82 × 105, attributed to the coupling between the amorphous shell and the crystalline core.

Oleylamine Aging of PtNi Nanoparticles Giving Enhanced Functionality for the Oxygen Reduction Reaction.

We report a rapid solution-phase strategy to synthesize alloyed PtNi nanoparticles which demonstrate outstanding functionality for the oxygen reduction reaction (ORR). This one-pot coreduction colloidal synthesis results in a monodisperse population of single-crystal nanoparticles of rhombic dodecahedral morphology with Pt-enriched edges and compositions close to Pt1Ni2. We use nanoscale 3D compositional analysis to reveal for the first time that oleylamine (OAm)-aging of the rhombic dodecahedral Pt1Ni2 particles results in Ni leaching from surface facets, producing aged particles with concave faceting, an exceptionally high surface area, and a composition of Pt2Ni1. We show that the modified atomic nanostructures catalytically outperform the original PtNi rhombic dodecahedral particles by more than two-fold and also yield improved cycling durability. Their functionality for the ORR far exceeds commercially available Pt/C nanoparticle electrocatalysts, both in terms of mass-specific activities (up to a 25-fold increase) and intrinsic area-specific activities (up to a 27-fold increase).

Enhanced Spin-Orbit Coupled Photoluminescence of Perovskite CsPbBr3 Quantum Dots by Piezo-Phototronic Effect.

Piezo-phototronic effect is a fundamental effect of semiconductors lacking of central symmetry with geometries from one-dimensional (1D) nanowire to 3D bulk. Here, we present that the piezo-phototronic effect can even tune a spin-orbit coupled photoluminescence (PL) based on all-inorganic perovskite CsPbBr3 quantum dots (QDs). Although the cubic structure of CsPbBr3 QDs is nonpiezoelectric, a cooling treatment can change it to an orthorhombic structure, which is proven to possess a piezoelectric property. The spin-orbit coupled PL intensity is demonstrated to be dependent on the polarization of the excited light. Because of the manipulation of the spin-split energy levels via the piezo-phototronic effect, the spin-orbit coupled PL intensities under a -0.9% compressive strain for linearly and circularly polarized light excitations can be enhanced by 136% and 146%, respectively. These findings reveal fundamental understandings of the spin-orbit coupled PL dynamics and demonstrate promising optoelectronic applications of the piezo-phototronic effect in these QDs.

Automated Single-Particle Reconstruction of Heterogeneous Inorganic Nanoparticles.

Single-particle reconstruction can be used to perform three-dimensional (3D) imaging of homogeneous populations of nano-sized objects, in particular viruses and proteins. Here, it is demonstrated that it can also be used to obtain 3D reconstructions of heterogeneous populations of inorganic nanoparticles. An automated acquisition scheme in a scanning transmission electron microscope is used to collect images of thousands of nanoparticles. Particle images are subsequently semi-automatically clustered in terms of their properties and separate 3D reconstructions are performed from selected particle image clusters. The result is a 3D dataset that is representative of the full population. The study demonstrates a methodology that allows 3D imaging and analysis of inorganic nanoparticles in a fully automated manner that is truly representative of large particle populations.

Imaging Three-Dimensional Elemental Inhomogeneity in Pt-Ni Nanoparticles Using Spectroscopic Single Particle Reconstruction.

The properties of nanoparticles are known to critically depend on their local chemistry but characterizing three-dimensional (3D) elemental segregation at the nanometer scale is highly challenging. Scanning transmission electron microscope (STEM) tomographic imaging is one of the few techniques able to measure local chemistry for inorganic nanoparticles but conventional methodologies often fail due to the high electron dose imparted. Here, we demonstrate realization of a new spectroscopic single particle reconstruction approach built on a method developed by structural biologists. We apply this technique to the imaging of PtNi nanocatalysts and find new evidence of a complex inhomogeneous alloying with a Pt-rich core, a Ni-rich hollow octahedral intermediate shell and a Pt-rich rhombic dodecahedral skeleton framework with less Pt at ⟨100⟩ vertices. The ability to gain evidence of local surface enrichment that varies with the crystallographic orientation of facets and vertices is expected to provide significant insight toward the development of nanoparticles for sensing, medical imaging, and catalysis.

Cumulative use of therapeutic bladder anticholinergics and the risk of dementia in patients with lower urinary tract symptoms: a nationwide 12-year cohort study.

BACKGROUND: Studies have shown an association between lower urinary tract symptoms (LUTS) and an increased risk of dementia. Whether anticholinergic use contributes to the development of dementia in patients with LUTS remains unknown, especially in Asian populations. This study aims to investigate the association between anticholinergic use and dementia in patients with LUTS. METHODS: This study included patients aged 50 years and over with newly diagnosed LUTS (January 2001 to December 2005), divided into four groups according to their cumulative defined daily doses (cDDDs) of anticholinergics: < 28 cDDDs, 28-84 cDDDs, 85-336 cDDDs, ≥337 cDDDs. Patients were followed up until dementia developed or until the end of 2012. RESULTS: We recruited a total of 16,412 patients. The incidence of dementia was 10% in the < 28 cDDD group, 8.9% in the 28-84 cDDD group, 11.5% in the 85-336 cDDD group, and 14.4% in the ≥337 cDDD group (p = .005). In a Cox proportional hazards analysis, the adjusted hazard ratio of dementia was 1.15 (95% CI = 0.97-1.37) in the 85-336 cDDD group, and 1.40 (95% CI = 1.12-1.75) in the ≥337 cDDD group after adjusting for covariates. CONCLUSIONS: Our study indicates that higher cumulative anticholinergic exposure is associated with an increase in the risk of incident dementia in patients with LUTS aged 50 years of age and over. Either using one anticholinergic agent or switching anticholinergic agents cumulatively increases this risk. Therapeutic risks and benefits of using anticholinergics in LUTS treatment should be clinically reviewed and weighed.

Controlling Reaction Selectivity over Hybrid Plasmonic Nanocatalysts.

The localized surface plasmon resonance (LSPR) excitation in plasmonic nanoparticles has been used to accelerate several catalytic transformations under visible-light irradiation. In order to fully harness the potential of plasmonic catalysis, multimetallic nanoparticles containing a plasmonic and a catalytic component, where LSPR-excited energetic charge carriers and the intrinsic catalytic active sites work synergistically, have raised increased attention. Despite several exciting studies observing rate enhancements, controlling reaction selectivity remains very challenging. Here, by employing multimetallic nanoparticles combining Au, Ag, and Pt in an Au@Ag@Pt core-shell and an Au@AgPt nanorattle architectures, we demonstrate that reaction selectivity of a sequential reaction can be controlled under visible light illumination. The control of the reaction selectivity in plasmonic catalysis was demonstrated for the hydrogenation of phenylacetylene as a model transformation. We have found that the localized interaction between the triple bond in phenylacetylene and the Pt nanoparticle surface enables selective hydrogenation of the triple bond (relative to the double bond in styrene) under visible light illumination. Atomistic calculations show that the enhanced selectivity toward the partial hydrogenation product is driven by distinct adsorption configurations and charge delocalization of the reactant and the reaction intermediate at the catalyst surface. We believe these results will contribute to the use of plasmonic catalysis to drive and control a wealth of selective molecular transformations under ecofriendly conditions and visible light illumination.

Role of Intracellular Na+ in the Regulation of [Ca2+]i in the Rat Suprachiasmatic Nucleus Neurons.

Transmembrane Ca2+ influx is essential to the proper functioning of the central clock in the suprachiasmatic nucleus (SCN). In the rat SCN neurons, the clearance of somatic Ca2+ following depolarization-induced Ca2+ transients involves Ca2+ extrusion via Na+/Ca2+ exchanger (NCX) and mitochondrial Ca2+ buffering. Here we show an important role of intracellular Na+ in the regulation of [Ca2+]i in these neurons. The effect of Na+ loading on [Ca2+]i was determined with the Na+ ionophore monensin and the cardiac glycoside ouabain to block Na+/K+-ATPase (NKA). Ratiometric Na+ and Ca2+ imaging was used to measure the change in [Na+]i and [Ca2+]i, and cell-attached recordings to investigate the effects of monensin and ouabain on spontaneous firing. Our results show that in spite of opposite effects on spontaneous firing and basal [Ca2+], both monensin and ouabain induced Na+ loading, and increased the peak amplitude, slowed the fast decay rate, and enhanced the slow decay phase of 20 mM K+-evoked Ca2+ transients. Furthermore, both ouabain and monensin preferentially enhanced nimodipine-insensitive Ca2+ transients. Together, our results indicate that in the SCN neurons the NKA plays an important role in regulating [Ca2+]i, in particular, associated with nimodipine-insensitive Ca2+ channels.

Differential regulation of nimodipine-sensitive and -insensitive Ca2+ influx by the Na+/Ca2+ exchanger and mitochondria in the rat suprachiasmatic nucleus neurons.

BACKGROUND: Transmembrane Ca2+ influx is critical for molecular rhythmicity, metabolic activity, and neuropeptide release in the central clock of the suprachiasmatic nucleus (SCN). We previously reported that both the Na+/Ca2+ exchanger (NCX) and mitochondria play a role in regulating intracellular Ca2+ homeostasis in the rat SCN neurons. Here we present evidence to show differential regulation by NCX and mitochondria of nimodipine-sensitive and -insensitive Ca2+ influx. METHODS: Ratiometric Ca2+ imaging was used to measure change in [Ca2+]i and patch clamp recordings to study spontaneous firing, membrane potential, and voltage-dependent Ca2+ channels in neurons from reduced SCN slice preparations. Immunofluorescent staining was used to determine the distribution pattern of CaV1.2 and CaV1.3 and their colocalization with NCX1. RESULTS: Ratiometric Ca2+ imaging indicates that nimodipine (2 µM) blocked most of 20 (mM) K+-induced, but less so of 50 K+-induced, Ca2+ rise. The nimodipine-sensitive 50 K+-induced Ca2+ transient rose more rapidly but decayed similarly with the nimodipine-insensitive component, suggesting both components were extruded by NCX. Immunofluorescent stains showed the expression of both CaV1.2 and CaV1.3 and their colocalization with NCX1, whereas functional studies suggest that CaV1.2 mediated most of the nimodipine-sensitive Ca2+ rise but had insignificant effect on spontaneous firing. After normalization relative to the Ca2+-free solution, nimodipine reduced ~ 65% of basal Ca2+ influx, and TTX lowered it by ~ 35%, leaving ~ 25% basal Ca2+ influx in the combined presence of TTX and nimodipine. With the mitochondrial uncoupler carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) to inhibit mitochondrial Ca2+ uptake, 20 K+-induced Ca2+ transients became larger and slower, both in the absence and presence of nimodipine. FCCP markedly enhanced nimodipine-insensitive, but not nimodipine-sensitive, Ca2+ transients, suggesting that mitochondria preferentially buffer nimodipine-insensitive Ca2+ influx. Results from using CaV2 channel blockers further indicate that FCCP enhanced Ca2+ transients mediated by N-, P/Q-, and the blocker cocktail-insensitive Ca2+ channels. CONCLUSIONS: The differential regulation of transmembrane Ca2+ influx by NCX and mitochondria suggests that Ca2+ entry via different sources may be regulated differently to play different roles in SCN physiology.

2- O- N-Benzylcarbamoyl as a Protecting Group To Promote ß-Selective Glycosylation and Its Applications in the Stereoselective Synthesis of Oligosaccharides.

This study examines the utility of the N-benzylcarbamoyl (BnCar) protecting group in glycosylation reactions of the parent O-2 protected carbohydrate donor. It was found that the BnCar group imparted exclusively ß-selectivity with primary and secondary alcohols. A mechanistic study revealed the activated intermediate to be the glycosyl triflate in a skew conformation, which results in ß-selective glycosylation via an SN2-like pathway. The BnCar group can be readily cleaved using tetrabutylammonium nitrite, without affecting ester and ether protecting groups. Taken together, these results show BnCar to be useful for the synthesis of complex oligosaccharides, an undertaking that requires delicate chemical differentiation of various protecting groups.

Role of Na⁺/Ca²âº exchanger in Ca²âº homeostasis in rat suprachiasmatic nucleus neurons.

Intracellular Ca(2+) is critical to the central clock of the suprachiasmatic nucleus (SCN). However, the role of Na(+)/Ca(2+) exchanger (NCX) in intracellular Ca(2+) concentration ([Ca(2+)]i) homeostasis in the SCN is unknown. Here we show that NCX is an important mechanism for somatic Ca(2+) clearance in SCN neurons. In control conditions Na(+)-free solution lowered [Ca(2+)]i by inhibiting TTX-sensitive as well as nimodipine-sensitive Ca(2+) influx. With use of the Na(+) ionophore monensin to raise intracellular Na(+) concentration ([Na(+)]i), Na(+)-free solution provoked rapid Ca(2+) uptake via reverse NCX. The peak amplitude of 0 Na(+)-induced [Ca(2+)]i increase was larger during the day than at night, with no difference between dorsal and ventral SCN neurons. Ca(2+) extrusion via forward NCX was studied by determining the effect of Na(+) removal on Ca(2+) clearance after high-K(+)-induced Ca(2+) loads. The clearance of Ca(2+) proceeded with two exponential decay phases, with the fast decay having total signal amplitude of ∼85% and a time constant of ∼7 s. Na(+)-free solution slowed the fast decay rate threefold, whereas mitochondrial protonophore prolonged mostly the slow decay. In contrast, blockade of plasmalemmal and sarco(endo)plasmic reticulum Ca(2+) pumps had little effect on the kinetics of Ca(2+) clearance. RT-PCR indicated the expression of NCX1 and NCX2 mRNAs. Immunohistochemical staining showed the presence of NCX1 immunoreactivity in the whole SCN but restricted distribution of NCX2 immunoreactivity in the ventrolateral SCN. Together our results demonstrate an important role of NCX, most likely NCX1, as well as mitochondrial Ca(2+) uptake in clearing somatic Ca(2+) after depolarization-induced Ca(2+) influx in SCN neurons.

Cefepime-induced encephalopathy in an older patient with polypharmacy and renal insufficiency: a case report.

The world population is rapidly aging. Societal aging poses many challenges for individuals, families, nations, and the global healthcare system. Therefore, geriatric care is a crucial issue that demands our attention. In this case report, we describe a woman in her early 70s with multiple comorbidities, polypharmacy, and renal insufficiency who developed cefepime-induced encephalopathy with moderate to severe cerebral dysfunction during treatment of a urinary tract infection. The patient's consciousness level gradually improved, and no further seizures were observed following the discontinuation of cefepime for several days. This case report underscores the fact that polypharmacy and medication safety are significant concerns that are often overlooked when caring for older patients. The report also highlights the increased susceptibility of older individuals to antibiotic-associated adverse reactions during the management of infectious diseases. Therefore, optimization of antibiotic therapy for older patients is a critical issue that requires thorough investigation and consideration in geriatric care.

Mortality rate and its determinants among people with dementia receiving home healthcare: a nationwide cohort study.

People with dementia (PwD) who receive home healthcare (HHC) may have distressing symptoms, complex care needs and high mortality rates. However, there are few studies investigating the determinants of mortality in HHC recipients. To identify end-of-life care needs and tailor individualized care goals, we aim to explore the mortality rate and its determinants among PwD receiving HHC. We conducted a retrospective cohort study using a Taiwanese national population database. People with new dementia diagnosis in 2007-2016 who received HHC were included. We calculated the accumulative mortality rate and applied Poisson regression model to estimate the risk of mortality for each variable (adjusted risk ratios, aRR) with a 95% confidence interval (CI). We included 95,831 PwD and 57,036 (59.5%) of them died during the follow-up period (30.5% died in the first-year). Among comorbidities, cirrhosis was associated with the highest mortality risks (aRR 1.65, 95% CI 1.49-1.83). Among HHC-related factors, higher visit frequency of HHC (> 2 versus ≦1 times/month, aRR 3.52, 95% CI 3.39-3.66) and higher level of resource utilization group (RUG, RUG 4 versus 1, aRR = 1.38, 95% CI 1.25-1.51) were risk factor of mortality risk. Meanwhile, HHC provided by physician and nurse was related to reduced mortality risk (aRR 0.79, 95% CI 0.77-0.81) compared to those provided by nurse only. Anticipatory care planning and timely end-of life care should be integrated in light of the high mortality rate among PwD receiving HHC. Determinants associated with increased mortality risk facilitate the identification of high risk group and tailoring the appropriate care goals. Trial registration number: ClinicalTrials.gov Identifier is NCT04250103 which has been registered on 31st January 2020.