With the increasing demand for highly efficient and durable catalysts, researchers have been doing extensive research to engineer the shape, size, and even phase (e.g., hcp or fcc Co) of individual ...catalyst nanoparticles, as well as the interface structure between the catalyst and support. In this work, cobalt oxides were deposited on ceria with rod-like morphology (CeO
NR) and cube-like morphology (CeO
NC) and silica with sphere-like morphology (SiO
NS) via a precipitation-deposition method to investigate the effects of support morphology, surface defects, support reducibility, and the metal-support interactions on redox and catalytic properties. XRD, Raman, XPS, BET, H
-TPR, O
-TPD, CO-TPD, TEM, and TPR/TPO cycling measurements have been mainly employed for catalysts characterization. Compared with CeO
NC and SiO
NS supports, as well as CeO
NC- and SiO
NS-supported cobalt catalysts, CeO
NR counterparts exhibited enhanced reducibility and CO oxidation performance at a lower temperature. Both the apparent activation energy and CO conversion demonstrated the following catalytic activity order: 10 wt % CoO
/CeO
NR > 10 wt % CoO
/CeO
NC > 10 wt % CoO
/SiO
NS. These results showed a strong support-dependent reducibility, CO oxidation, and redox cycling activity/stability of the as-prepared catalysts. Moreover, the significantly enhanced catalytic CO oxidation of the 10 wt % CoO
/CeO
NR catalyst indicated the vital role of CeO
NR support with rich surface oxygen vacancies, superior oxygen storage capacity and mobility, and excellent adsorption/desorption behavior of CO and O
species.
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Temperature-programmed desorption (TPD) with ammonia is widely used for zeolite characterization revealing information on acidity and adsorption sites. The interpretation of TPD measurements is, ...however, often challenging. One example is the NH 3 -TPD profile from Cu-chabazite (Cu-CHA) which generally is deconvoluted in three peaks with contributions from NH 3 on Lewis acid sites, copper sites and Brønsted acid sites. Here, we use density functional theory calculations combined with kinetic simulations to analyze this case. We find a large number of possible species, giving rise to overlapping features in the NH 3 -TPD. The experimental low-temperature peak (below 200∘C) is assigned to NH 3 desorption from Lewis acid sites together with NH 3 desorption from a Cu(II)(OH)(NH3)3+ complex. The intermediate-temperature peak (250-350∘C) is attributed to decomposition of a linear Cu(I)(NH3)2+ complex and a residual from Cu(II)(OH)(NH3)3+. The high-temperature peak is predicted to have contributions from Brønsted acid sites (NH4+), Cu(I)NH3+ and Cu(II)(NH3)42+. The present work shows that NH 3 -TPD from Cu-CHA can be reconciled with copper complexes as NH 3 storage sites.
The review deals with surface reactions of the complex uranium oxide systems with relevance to catalysis and the environment. After a brief introduction on the properties of uranium oxides, the focus ...of the review is on surface science studies of defined structures of uranium oxides which are entirely on UO
2 because of the lack of available model on other uranium oxide systems. Powder work is also included as it has given considerable information related to the dynamics between the many phases of uranium oxides. Many chemical reactions are mapped and these include water dissociative adsorption and reaction, CO oxidation and reductive coupling, as well as the reaction of oxygen containing organic compounds such as alcohols, aldehydes, ketones and carboxylic acids in addition to a few examples of sulfur and nitrogen containing compounds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
As a severe emerging shrimp disease, TPD has heavily impacted the shrimp aquaculture industry and resulted in serious economic losses in China since spring 2020. This study aimed to identify the key ...virulent factors and related genes of the
, for a better understanding of its pathogenicity of the novel highly lethal infectious pathogen, as well as its molecular epidemiological characteristics in China. The present study revealed that a novel protein,
high virulent protein-2 (MW >100 kDa), is responsible to the lethal virulence of
to shrimp post-larvae. The results are essential for effectively diagnosing and monitoring novel pathogenic bacteria, like
, in aquaculture shrimps and would be beneficial to the fisheries department in early warning of
emergence and developing prevention strategies to reduce economic losses due to severe outbreaks of TPD. Elucidation of the key virulence genes and genomics of
could also provide valuable information on the evolution and ecology of this emerging pathogen in aquaculture environments.
Proteolysis-targeting chimeras (PROTACs) are heterobifunctional molecules consisting of two ligands joined by a linker, enabling them to simultaneously bind with an E3 ligase and a protein of ...interest (POI) and trigger proteasomal degradation of the POI. Limitations of PROTAC include lack of potent E3 ligands, poor cell selectivity, and low permeability. AS1411 is an antitumor aptamer specifically recognizing a membrane-nucleus shuttling nucleolin (NCL). Here, we repurpose AS1411 as a ligand for an E3 ligase mouse double minute 2 homolog (MDM2) via anchoring the NCL-MDM2 complex. Then, we construct an AS1411-NCL-MDM2-based PROTAC (ANM-PROTAC) by conjugating AS1411 with large-molecular-weight ligands for “undruggable” oncogenic STAT3, c-Myc, p53-R175H, and AR-V7. We show that the ANM-PROTAC efficiently penetrates tumor cells, recruits MDM2 and degrades the POIs. The ANM-PROTAC achieves tumor-selective distribution and exhibits excellent antitumor activity with no systemic toxicity. This is a PROTAC with built-in tumor-targeting and cell-penetrating capacities.
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•AS1411 is repurposed as a ligand for MDM2 via anchoring the NCL-MDM2 complex•The ANM-PROTAC is constructed via conjugating AS1411 with ligands for POIs•The ANM-PROTAC selectively recognizes and penetrates tumor cells and degrades POIs•The ANM-PROTAC displays potent antitumor activity with no obvious toxicity
Fu et al. repurpose AS1411 to generate a PROTAC, called ANM-PROTAC that can recruit MDM2 through its interaction with NCL. The ANM-PROTACs display excellent tumor-targeting and -penetrating capacities, with no detectable toxicity in tumor xenograft mice.
To identify Hf species and quantitatively evaluate their acid properties, combined measurement of infrared (IR) and temperature-programmed desorption (TPD) with deuterated acetonitrile (CD3CN) as ...probe molecule was performed on Hf-Beta and HfO2/Si-Beta. IR spectra of CD3CN adsorbed on Hf-Beta showed five types of Hf species including framework open and closed Hf sites, extra-framework HfO2, and two types of Hf species bearing hydroxy groups. IR measurement showed structural change in Hf-Beta upon exposing to water vapor with generation of the two types of Hf species bearing hydroxy groups. Integrated molar extinction coefficients for C N stretching vibration of CD3CN adsorbed on these Hf species were estimated and the number of each Hf acid site was calculated. Acid strength of these Hf species was estimated from CD3CN-TPD measurement in combination with IR; the acid strength of the open and closed Hf sites, extra-framework HfO2 species, and the other Hf species was found to be strong, moderate, and weak, respectively.
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•CD3CN IR-TPD can distinguish and quantify Hf species on Hf-Beta zeolite.•IR measurement distinguished five types of Hf species present on Hf-Beta.•Integrated molar extinction coefficients for adsorbed CD3CN were estimated.•The number of each Hf acid site was calculated.•Acid strength of these Hf species was estimated by TPD measurement of CD3CN.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lean exhausts aftertreatment has been the subject of numerous investigations due to ever stringent regulations on pollutants emissions such as that of NOx. Among aftertreatment technologies, the ...selective catalytic reduction of NOx by the hydrocarbons (HC-SCR) has been studied intensively, in particular by using Ag/Al2O3 materials. The present work highlights that pretreatment of pristine Al2O3 in warm water prior to Ag deposition allows to prepare catalysts of significantly higher (H2-)C3H6-SCR performance compared to conventional Ag/Al2O3 catalysts. In addition, NOx-TPD-C3H6-SCR structure-activity correlations indicate that optimum composition of the Ag/Al2O3 catalysts can be improved by about 50% in terms of Ag content for the first time. Unprecedented in-depth NMR investigations allow for the identification of the alumina sites of importance in the anchoring of Ag. These sites are µ1-OH groups located near the (100)/(110)l edge and then near the (110)b/(100) edge of Al2O3 crystallites and bonded to octahedrally coordinated Al species.
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•Remarkable NOx-TPD-C3H6-SCR structure-activity correlations are highlighted.•Optimum Ag loading on Al2O3 is increased by about 50% compared to conventional samples.•In-depth NMR investigations allow to unravel Al2O3 sites of importance in anchoring Ag.•µ1-OH groups located near the (100)/(110)l edge are the Ag anchoring sites of Al2O3.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Research on in-service Science, Technology, Engineering, and Math (STEM) Teacher Professional Development (TPD) has received attention in the last decade, but has not produced conclusive findings. ...This study aimed to examine the trends of STEM TPD programmes by applying several proposed frameworks. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were employed to analyse 44 journal articles on in-service STEM TPD programmes. The results of this study revealed that constructivist theory was the most widely adopted learning theories. Moreover, workshop, training, and online TPD were the most frequently used learning models. The research conclusion indicates that future STEM TPD requires more involvement of school principals in encouraging STEM teachers to develop their professionalism through the necessary in-service TPD programs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Thiol, pH and inorganic phosphorus decrease whereas TSC rises with TPD process.•A small numberof TPD-related genes are constantly regulated with TPD process.•TPD-related genes are related to protein ...metabolism, PCD, stress responses, etc.•Typical symptoms of TPD tree owes to lower IPP and downregulating LBF-related genes.
Tapping panel dryness (TPD) has become the mostimportant limiting factor for increasing natural rubber yield, whereas illuminating the molecular mechanisms underlying TPD is the prerequisite for solving the problem of TPD. However, molecular mechanisms underlying TPD are largely unknown. In this study, healthy and different stages of TPD-affected rubber trees were utilized to analyze TPD for the first time. We found that the changing tendencies of key latex physiological parameters were closely related to TPD occurrence and development. To reveal the molecular mechanisms underlying TPD, we sequenced and compared bark transcriptomes among healthy rubber tree, and TPD-affected ones at initial and advanced stages. In total, 8607 genes were identified as TPD-related genes in contrast to healthy rubber tree. According to gene expression profiles, the five samples were divided into three groups including healthy rubber tree, and TPD-affected rubber tree in the initial and advanced stages, which was consistent with the stages of TPD occurrence and development. Interestingly, only asmall proportionof the TPD-related genes were constantly down- or up-regulated with TPD occurrence and development. The TPD-related genes in KEGG pathways significantly enriched were closely associated with protein metabolism, cell division and differentiation, PCD, stress responses, terpene biosynthesis, and various metabolism processes. Moreover, overexpression of HbAPX2 identified as a TPD-related gene enhanced oxidative stress tolerance in S. cerevisiae. The typical symptoms of TPD, partial or complete dry zone (no latex flow) on tapping panel, might attribute to lower IPP available for rubber biosynthesis, and downregulation of the genes in post-IPP steps of rubber biosynthesis and the genes involved in latex flow. Our results not only provide new insights into molecular mechanisms underlying TPD occurrence and development but also contribute to developing effective measures to control TPD in rubber trees.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This mixed-method study is based on interviews with 60 elementary-school teachers who participated in TPD (Teacher professional development) during two periods of the Covid-19 pandemic. Teachers were ...in early, middle and senior career stages. Teacher statements revealed three categories: (1) Informal and formal TPD - without appropriate formal TPD, teachers, especially those in the middle and senior career stages, turned to colleagues and to social media to cope with online instruction. (2) Self-regulated learning, in which teachers listed their motivating factors and expressed their TPD difficulties during the Covid-19 periods. (3) Perceived learning - the cognitive aspect was found to be higher than the emotional and social aspects, especially during the first Covid-19 period. The practical recommendations are intended for policy makers, to adapt the TPD system to teachers' particular needs according to their 'career cycle', in order to cope with technology-integrated learning-teaching challenges, even in routine teaching.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
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