Biogas, a mixture of methane and carbon dioxide produced from microbial digestion of biomass, waste, or residues, has gained increasing attention from scientists as a valuable resource for producing ...syngas. This study investigated the effects of different promoters, including calcium, copper, and chromium compounds, on the performance of nickel-based catalysts in biogas reforming. The catalysts were prepared by co-impregnating nickel precursors with the promoters onto the support using the incipient wetness method. The addition of calcium and chromium oxides improved nickel dispersibility, enhanced reducibility, and provided adequate basicity, resulting in superior catalytic activity. Among the promoted catalysts, 0.1Ca–1Ni/Al2O3 demonstrated the best performance with 72% CH4 and 74% CO2 conversions and no significant loss in catalytic activity after 6 h. Additionally, the study found that the basicity of the material was proportional to the transition of amorphous coke into graphitic type, and the advantages and disadvantages of each type of coke were thoroughly discussed.
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•The study of Ca, Cr, and Cu promoted on Ni/Al2O3 catalyst for simulated-biogas dry reforming.•In the presence of promoter, nickel dispersibility, reducibility and overall catalytic basicity were all improved.•30% enhancement in both methane and carbon dioxide conversions obtained with 0.1Ca–1Ni/Al2O3.•Coke can be suppressed at an adequate basicity.•Graphitic carbon was a preferable form of coke at a high catalyst basicity.
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•Dy addition significantly enhanced the basicity of Co/Al2O3 catalyst.•0.3 wt%Dy was the best loading for activity and deposited carbon mitigation.•Dy promotion mitigated carbon ...deposition because of its redox cycling character.•H2/CO ratios varied within 0.70–0.86 at 973 K.
Dysprosium (Dy) promoted Co/Al2O3 catalysts with different Dy loadings (0-3 wt%) were synthesized via an impregnation approach for methane dry reforming. Promoter addition enhanced the basicity of catalysts owing to the basic attribute of Dy2O3. Co3O4 crystallite sizes were reduced from 8.15 to 6.68 nm with 0.1–0.3 wt%Dy promotion due to the diluting effect, resulting in higher metal dispersion. Particularly, at 973 K, 0.3 wt%Dy appeared as the best promoter loading and achieved the highest CH4 conversion, as well as H2 and CO yields of the corresponding 79.4%, 65.8% and 89.2% because of growing basic site density and the enhancing number of Co active sites. The temperature-programmed oxidation analyses also revealed that 0.3%Dy-10%Co/Al2O3 suppressed carbonaceous deposition from 12.84% to 7.76% since the extra oxygen mobility and redox cycling of Dy2O3 could effectively oxidize surface carbonaceous species to CO and H2.
The under-representation of several ethnic groups in existing genetic databases and studies have undermined our understanding of the genetic variations and associated traits or diseases in many ...populations. Cost and technology limitations remain the challenges in performing large-scale genome sequencing projects in many developing countries, including Vietnam. As one of the most rapidly adopted genetic tests, non-invasive prenatal testing (NIPT) data offers an alternative untapped resource for genetic studies. Here we performed a large-scale genomic analysis of 2683 pregnant Vietnamese women using their NIPT data and identified a comprehensive set of 8,054,515 single-nucleotide polymorphisms, among which 8.2% were new to the Vietnamese population. Our study also revealed 24,487 disease-associated genetic variants and their allele frequency distribution, especially 5 pathogenic variants for prevalent genetic disorders in Vietnam. We also observed major discrepancies in the allele frequency distribution of disease-associated genetic variants between the Vietnamese and other populations, thus highlighting a need for genome-wide association studies dedicated to the Vietnamese population. The resulted database of Vietnamese genetic variants, their allele frequency distribution, and their associated diseases presents a valuable resource for future genetic studies.
Vietnam has a high thalassemia burden. We collected blood samples from 5880 pregnant Vietnamese women during prenatal health checks to assess thalassemia carrier frequency using combined ...gap-polymerase chain reaction (gap-PCR) and targeted next-generation sequencing (NGS). Thalassemia carriers were identified with prevalence of 13.13% (772), including 7.82% (460) carriers of α-thalassemia (α-thal), 5.31% (312) carriers of β-thalassemia (β-thal), and 0.63% (37) concurrent α-/β-thal carriers. Deletional mutations (368) accounted for 80.0% of α-thal carriers, of which, --
SEA
(Southeast Asian) (n = 254; 55.0%) was most prevalent, followed by the -α
3.7
(rightward) (n = 66; 14.0%) and -α
4.2
(leftward) (n = 45; 9.8%) deletions. Hb Westmead (HBA2: c.369C>G) (n = 53) and Hb Constant Spring (Hb CS or HBA2: c.427T>C) (in 28) are the two most common nondeletional α-globin variants, accounting for 11.5 and 6.0% of α-thal carriers. We detected 11 different β-thal genotypes. Hb E (HBB: c.79G>A) (in 211) accounted for 67.6% of β-thal carriers. The most common β-thal genotypes were associated with mutations at codon 17 (A>T) (HBB: c.52A>T), codons 41/42 (-TTCT) (HBB: c.126_129delCTTT), and codon 71/72 (+A) (HBB: c.217_218insA) (prevalence 0.70%, 0.68%, and 0.2%, respectively). Based on mutation frequencies calculated in this study, estimates of 5021 babies in Vietnam are affected with clinically severe thalassemia annually. Our data suggest a higher thalassemia carrier frequency in Vietnam than previously reported. We established that combining NGS with gap-PCR creates an effective large-scale thalassemia screening method that can detect a broad range of mutations.
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•A semi-nested, heptaplex RT-PCR assay for SARS-CoV-2 detection has been developed.•The complex melting spectrum was interpreted by an artificial intelligence algorithm.•The developed ...assay enables 96-sample pooled testing for increase of testing capacity.•About 8,000 pre-amplified samples could be screened in one realtime PCR run.
Asymptomatic transmission was found to be the Achilles’ heel of the symptom-based screening strategy, necessitating the implementation of mass testing to efficiently contain the transmission of COVID-19 pandemic. However, the global shortage of molecular reagents and the low throughput of available realtime PCR facilities were major limiting factors.
A novel semi-nested and heptaplex (7-plex) RT-PCR assay with melting analysis for detection of SARS-CoV-2 RNA has been established for either individual testing or 96-sample pooled testing. The complex melting spectrum collected from the heptaplex RT-PCR amplicons was interpreted with the support of an artificial intelligence algorithm for the detection of SARS-CoV-2 RNA. The analytical and clinical performance of the semi-nested RT-PCR assay was evaluated using RNAs synthesized in-vitro and those isolated from nasopharyngeal samples.
The LOD of the assay for individual testing was estimated to be 7.2 copies/reaction. Clinical performance evaluation indicated a sensitivity of 100% (95% CI: 97.83–100) and a specificity of 99.87% (95% CI: 99.55–99.98). More importantly, the assay supports a breakthrough sample pooling method, which makes possible parallel screening of up to 96 samples in one real-time PCR well without loss of sensitivity. As a result, up to 8,820 individual pre-amplified samples could be screened for SARS-CoV-2 within each 96-well plate of realtime PCR using the pooled testing procedure.
The novel semi-nested RT-PCR assay provides a solution for highly multiplex (7-plex) detection of SARS-CoV-2 and enables 96-sample pooled detection for increase of testing capacity.
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The dry reforming of methane is a potential solution to mitigate the global warming effect. In this study, the effects of various preparation methods including the impregnation, coprecipitation, and ...combined coprecipitation-impregnation on physical characteristics and DRM catalytic performance of Ni-CeO2-Al2O3 were investigated. The synthetic procedure was discovered to have a crucial role in the basicity and reducibility, as well as nickel dispersion of catalyst. With affordable basicity and high reducibility, the combination of coprecipitation-impregnation exhibited the best performance with CH4 and CO2 steady-state conversions of 72% and 82%, respectively. Moreover, the deactivation of catalysts was also studied. The formation of low graphitic type showed less harmful to catalyst.
Background
The COVID‐19 pandemic caused by SARS‐CoV‐2 remains public health burdens and many unresolved issues worldwide. Molecular assays based on real‐time RT‐PCR are critical for the detection of ...SARS‐CoV‐2 in clinical specimens from patients suspected of COVID‐19.
Objective
We aimed to establish and validate an in‐house real‐time RT‐PCR for the detection of SARS‐CoV‐2.
Methodology
Primers and probes sets in our in‐house real‐time RT‐PCR assay were designed in conserved regions of the N and E target genes. Optimized multiplex real‐time RT‐PCR assay was validated using the first WHO International Standard (NIBSC code: 20/146) and evaluated clinical performance.
Results
The limit of detection validated using the first WHO International Standard was 159 IU/ml for both E and N target genes. The evaluation of clinical performance on 170 clinical samples showed a positive percent agreement of 100% and the negative percent agreement of 99.08% for both target genes. The Kappa value of 0.99 was an excellent agreement, the strong correlation of Ct values observed between two tests with r2 = 0.84 for the E gene and 0.87 for the N gene. Notably, we assessed on 60 paired saliva and nasopharyngeal samples. The overall agreement was 91.66%, and Kappa value of 0.74 showed a high agreement between two types of samples. When using nasopharyngeal swabs as the reference standard, positive percent agreement, and negative percent agreement were 91.83% and 90.90%, respectively.
Conclusion
In the present study, we established and validated an in‐house real‐time RT‐PCR for molecular detection of SARS‐CoV‐2 in a resource‐limited country.
Sonication-assisted nanoprecipitation provides an effective tool for nanomedicine engineering in therapeutic improvement. In the scope of this review, original works in interdisciplinary areas of ...using sonication with precipitation method for nanoparticulate drug delivery systems and its applications in management of different diseases are discussed. The use of sonication-assisted nanoprecipitation has been proved to improve drug bioavailability, which attracts tremendous interests as an effective strategy for drug delivery. However, many challenges still remain. To overcome these barriers, different approaches such as precipitation method, rational design, optimization and modification have been investigated. Accordingly, current knowledge of sonication-assisted nanoprecipitation proposes a broad perspective and optimization for the applications of nanotechnology in drug delivery.
s
This study reported comprehensive and systematic investigations on size and shape control of silver nanoplates (SNPs) through a simple synthesis route where individual effects of each reactant on ...surface plasmon resonance of silver nanoplates were thoroughly investigated. SNPs were successfully fabricated via chemical reduction of AgNO
3
with the aid of TSC, PVP, NaBH
4
, and H
2
O
2
as a primary capping agent, secondary capping agent, reducing agent, and oxidative etchant, respectively. The role and effects of each reagent on the size and uniformity of SNPs during the synthesis were deeply investigated. The results showed that both TSC and H
2
O
2
played critical roles in the growth of SNPs. Sufficient amount of TSC in the solution (TSC:Ag
+
molar ratio ≤ 22.5) would favor the formation of small-sized SNPs, while large-sized SNPs could be obtained at an excessive concentration of TSC. In addition to TSC, H
2
O
2
was also essential for the formation of SNPs whose size increased with the addition of H
2
O
2
. In contrast, PVP did not play a major role in the formation of SNPs. It functioned as a secondary capping agent to prevent the formation of larger SNPs and facilitated the production of small-sized SNPs with equal uniformity. This role of PVP was particularly significant at the low level of TSC. The results were crucial for deeply understanding the individual effects of each reagent on the size and uniformity of SNPs so as to control the size and shape of SNPs for better surface-enhanced Raman scattering (SERS) signals of 4-mercapto benzoic acid (4-MBA).
Silver nanodecahedrons were successfully synthesized by a photochemical method under irradiation of blue light-emitting diodes (LEDs). The formation of silver nanodecahedrons at different LED ...irradiation times (0–72 h) was thoroughly investigated by employing different characterization methods such as ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), and Raman spectroscopy. The results showed that silver nanodecahedrons (AgNDs) were formed from silver nanoseeds after 6 h of LED irradiation. The surface-enhanced Raman scattering (SERS) effects of the synthesized AgNDs were also studied in comparison with those of spherical silver nanoparticles in the detection of 4-mercapto benzoic acid. Silver nanodecahedrons with a size of 48 nm formed after 48 h of LED irradiation displayed stronger SERS properties than spherical nanoparticles because of electromagnetic enhancement. The formation mechanism of silver nanodecahedrons is also reported in our study. The results showed that multihedral silver nanoseeds favored the formation of silver nanodecahedrons.
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