Dendrimers, by virtue of their unique well-defined dendritic structure and multivalent cooperativity, hold great promise for a wide variety of applications, ranging from healthcare to energy ...production and environmental sustainability. However, dendrimer synthesis suffers from two inherent problems which greatly handicap their development and limit their application: the formation of structural defects caused by incomplete or side reactions, and difficulties associated with purification. Solid-phase synthesis may overcome both these problems, firstly by enabling complete chemical reactions through the use of a large excess of reagents, secondly by facilitating purification through simple washing and filtering steps. The end result is the speeded up reactions producing the desired product in high yield, with simultaneous suppression of by-products. In this review, we present the challenges and current state of research in solid-phase dendrimer synthesis, and provide our perspectives on its future development. We start with a short introduction to solid-phase synthesis and specific considerations for dendrimer construction. We then present exemplary studies to highlight the potential of, and challenges faced by, solid-phase dendrimer synthesis. Finally, we describe efforts to deliver more effective and reliable methods that will transform the synthesis of dendrimers and permit exploitation of their full potential.
The development of energy storage technology is beneficial for the efficient use of energy and sustainable development. As an effectual approach for storing and transporting thermal energy, latent ...heat storage using phase change materials (PCMs) has attracted tremendous attention. However, low thermal conductivity, poor stability, and leakages are considerable challenges to the widespread application of solid-liquid PCMs. Composite phase change materials (CPCMs) were prepared by combining expanded graphite (EG) and sodium acetate trihydrate (CH
3
COONa·3H
2
O, SAT). EG as a supporting material plays a crucial part in both enhancing the thermal conductivity and preventing the melted PCMs from leakage. The chemical structure, micromorphology, thermal stability, thermal conductivity, phase change behavior and heat storage performance of SAT/EG CPCMs have been extensively investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal conductivity analysis, differential scanning calorimetry (DSC), and cycling stability measurement. The results of SEM indicate that EG with a loose and porous layered structure has a good molding effect and can adsorb SAT well. XRD and FTIR results show that only a simple physical combination between EG and SAT exists, and no new substances have been produced. Compared with pure SAT, thermal conductivity and supercooling tests show that the supercooling degree of the CPCMs was decreased and the thermal conductivity was increased by 205.1%. In addition, the addition of 2 wt% of disodium hydrogen phosphate dodecahydrate (Na
2
HPO
4
·12H
2
O, DHPD) as a nucleating agent and 0.5 wt% of gelatin as a thickening agent to SAT could reduce the supercooling degree and inhibit the phase separation well. Based on SAT/EG-8% CPCMs, an oven with phase change energy storage was designed and the heat storage/release performance of the oven was investigated under different operating conditions.
The development of energy storage technology is beneficial for the efficient use of energy and sustainable development.
This randomized trial involving patients with HBeAg-negative chronic hepatitis B had the same design and findings as the companion trial involving patients with HBeAg-positive chronic hepatitis B. ...Histologic, biochemical, and virologic responses were better with entecavir than with lamivudine.
In patients with HBeAg-negative chronic hepatitis B, histologic, biochemical, and virologic responses were better with entecavir than with lamivudine.
Hepatitis B virus (HBV) infection is a serious global health concern. Approximately 350 million people worldwide are chronically infected, and 500,000 to 1.2 million deaths per year are attributed to HBV-associated complications.
1
,
2
A common variant of HBV infection occurs in patients who test negative for hepatitis B e antigen (HBeAg) and positive for antibodies against HBeAg (anti-HBe) and in whom serum HBV DNA and alanine aminotransferase levels remain persistently or intermittently elevated.
3
–
5
The median worldwide prevalence of HBeAg-negative disease in hepatitis B surface antigen (HBsAg)–positive carriers was reported to be 33 percent in 2002 and is increasing.
5
HBeAg-negative . . .
NFAT5 is the only known mammalian tonicity-responsive transcription factor with essential role in cellular adaptation to hypertonic stress. It is also implicated in diverse physiological and ...pathological processes. NFAT5 activity is tightly regulated by extracellular tonicity, but the underlying mechanisms remain elusive. We demonstrated that NFAT5 enters the nucleus via the nuclear pore complex. We found that NFAT5 utilizes a unique nuclear localization signal (NFAT5-NLS) for nuclear import. siRNA screening revealed that only karyopherin β1 (KPNB1), but not karyopherin alpha, is responsible for the nuclear import of NFAT5 via direct interaction with the NFAT5-NLS. Proteomics analysis and siRNA screening further revealed that nuclear export of NFAT5 under hypotonicity is driven by Exportin-T, where the process requires RuvB-Like AAA type ATPase 2 (RUVBL2) as an indispensable chaperone. Our findings have identified an unconventional tonicity-dependent nucleocytoplasmic trafficking pathway for NFAT5, a critical step in orchestrating rapid cellular adaptation to change in extracellular tonicity. These findings offer an opportunity for the development of novel NFAT5 targeting strategies that are potentially useful for the treatment of diseases associated with NFAT5 dysregulation.
Heterocyclic polymers have gained enormous attention for their unique functionalities and wide applications. In contrast with the well-studied polymer systems with five- or six-membered heterocycles, ...functional polymers with readily openable small-ring heterocycles have rarely been explored due to their large synthetic difficulty. Herein, a facile one-pot multicomponent polymerization to such polymers is developed. A series of functional polymers with multisubstituted and heteroatom-rich azetidine frameworks are efficiently generated at room temperature in high atom economy from handy monomers. The four-membered azetidine rings in the polymer skeletons can be easily transformed into amide and amidine moieties via a fast and efficient acid-mediated ring-opening reaction, producing brand-new polymeric materials with distinctive properties. All the as-prepared azetidine-containing polymers exhibit intrinsic visible luminescence in the solid state under long-wavelength UV irradiation even without conventionally conjugated structures. Such unconventional luminescence is attributed to the clusteroluminogens formed by through-space electronic interactions of heteroatoms and phenyl rings. All the obtained polymers show excellent optical transparency, high and tunable refractive indices, low optical dispersions and good photopatternability, which make them promising materials in various advanced electronic and optoelectronic devices. The ring-opened polymers can also function as a lysosome-specific fluorescent probe in biological imaging.
Abstract
The increasing frequency of heatwaves over East Asia (EA) is impacting agriculture, water management, and people’s livelihood. However, the effect of humidity on high-temperature events has ...not yet been fully explored. Using observations and future climate change projections conducted with the latest generation of Earth System models, we examine the mechanisms of dry and moist heatwaves over EA. In the dry heatwave region, anticyclonic circulation has been amplified after the onset of heatwaves under the influence of the convergence of anomalous wave activity flux over northern EA, resulting in surface warming via adiabatic processes. In contrast, the moist heatwaves are triggered by the locally generated anticyclonic anomalies, with the surface warming amplified by cloud and water vapor feedback. Model simulations from phase six of the Coupled Model Intercomparison Project projected display intensification of dry heatwaves and increased moist heatwave days in response to projected increases in greenhouse gas concentrations.
Background
Despite gout and hyperuricaemia being major comorbid health issues worldwide, there is a knowledge gap regarding their impact in the Australian community.
Aims
To determine the prevalence ...and associations of self‐reported medically diagnosed gout and hyperuricaemia in an Australian population‐based cohort.
Methods
The North West Adelaide Health Study is a longitudinal cohort study consisting of three stages of data collection. Each stage comprised a self‐complete questionnaire, clinic assessment and computer‐assisted telephone interview. In Stage 3 (2008–2010), participants were asked if a doctor had ever diagnosed them with gout. Additional data included demographics, comorbidities, laboratory data and Short Form 36 (SF‐36). Participants were defined as having gout if they had self‐reported medically diagnosed gout or were taking any gout‐specific medication (allopurinol, colchicine, probenecid). Hyperuricaemia was defined as a serum uric acid (SUA) level >0.42 mmol/L in men and >0.34 mmol/L in women.
Results
The overall prevalence of gout was 5.2%. Males were significantly more likely to have gout than females (8.5 vs 2.1%, P < 0.001). The overall prevalence of hyperuricaemia was 16.6%, with being male again identified as a significant risk factor (17.8 vs 15.4%, P < 0.01). Both gout and hyperuricaemia were associated with male sex, body mass index and renal disease after multivariable adjustment. There was no significant difference reported in quality of life (mean SF‐36) scores in participants with gout compared to unaffected individuals.
Conclusion
The prevalence of gout and hyperuricaemia is high in the South Australian population. This study emphasises the need for optimal diagnosis and management of gout in Australia.
BASS: Broad Network Based on Localized Stochastic Sensitivity Wang, Ting; Zhang, Mingyang; Zhang, Jianjun ...
IEEE transaction on neural networks and learning systems,
2024-Feb., 2024-Feb, 2024-2-00, 20240201, Letnik:
35, Številka:
2
Journal Article
The training of the standard broad learning system (BLS) concerns the optimization of its output weights via the minimization of both training mean square error (MSE) and a penalty term. However, it ...degrades the generalization capability and robustness of BLS when facing complex and noisy environments, especially when small perturbations or noise appear in input data. Therefore, this work proposes a broad network based on localized stochastic sensitivity (BASS) algorithm to tackle the issue of noise or input perturbations from a local perturbation perspective. The localized stochastic sensitivity (LSS) prompts an increase in the network's noise robustness by considering unseen samples located within a <inline-formula> <tex-math notation="LaTeX">Q </tex-math></inline-formula>-neighborhood of training samples, which enhances the generalization capability of BASS with respect to noisy and perturbed data. Then, three incremental learning algorithms are derived to update BASS quickly when new samples arrive or the network is deemed to be expanded, without retraining the entire model. Due to the inherent superiorities of the LSS, extensive experimental results on 13 benchmark datasets show that BASS yields better accuracies on various regression and classification problems. For instance, BASS uses fewer parameters (12.6 million) to yield 1% higher Top-1 accuracy in comparison to AlexNet (60 million) on the large-scale ImageNet (ILSVRC2012) dataset.
We report the growth of ZnO nanowires on ZnO:Ga/glass templates and the fabrication of laterally grown ZnO nanowire ethanol sensors. It was found that growth direction of the nanowires depends ...strongly on growth parameters. It was also found that resistivity of the fabricated sensor decreased upon ethanol gas injection. By introducing 1500
ppm ethanol gas, it was found that the device response were around 20%, 35%, 58% and 61% when the gas sensor was operated at 180
°C, 230
°C, 260
°C and 300
°C, respectively. It was also found that the device response at 300
°C were around 18%, 26%, 43%, 55% and 61% when the concentration of injected ethanol gas was 50
ppm, 100
ppm, 500
ppm, 1000
ppm and 1500
ppm, respectively.
Extracellular signals have been shown to impact on alternative pre-mRNA splicing; however, the molecular mechanisms and biological significance of signal-induced splicing regulation remain largely ...unknown. Here, we report that epidermal growth factor (EGF) induces splicing changes through ubiquitylation of a well-known splicing regulator, hnRNP A1. EGF signaling upregulates an E3 ubiquitin (Ub) ligase adaptor, SPRY domain-containing SOCS box protein 1 (SPSB1), which recruits Elongin B/C-Cullin complexes to conjugate lysine 29-linked polyUb chains onto hnRNP A1. Importantly, SPSB1 and ubiquitylation of hnRNP A1 have a critical role in EGF-driven cell migration. Mechanistically, EGF-induced ubiquitylation of hnRNP A1 together with the activation of SR protein kinases (SRPKs) results in the upregulation of a Rac1 splicing isoform, Rac1b, to promote cell motility. These findings unravel a novel crosstalk between protein ubiquitylation and alternative splicing in EGF/EGF receptor signaling, and identify a new EGF/SPSB1/hnRNP A1/Rac1 axis in modulating cell migration, which may have important implications for cancer treatment.
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