A theoretical analysis of the free vibration of discretely stiffened cylindrical shells with arbitrary end conditions

Theoretical analysis of free vibration of discretely stiffened cylindrical shells with arbitrary end condition

Evaluating Larch/C++ as a Specification Language = A Case Study Using the Microsoft Foundation Class Library

This paper attempts to evaluate Larch/C++, a formal specification language, as a means of more unambiguously documenting the interface specifications of C++ class libraries. In particular, the Microsoft Foundation Class Library is examined to demonstrate some of the advantages and disadvantages of using Larch/C++. Several different examples are presented with analysis. The reader is assumed to have some familiarity with C++ and the idea of formal specification, but need not know the Larch approach to formal specification

The influence of changing end conditions on the resonant response of beams and plates

Approximation method for structural beam and plate resonances at elastic edge excitation

An approximate theory for transverse shear deformation and rotatory inertia effects in vibrating beams

Transverse shear deformation and rotary inertia effects in vibrating beam

Certification of quantum state functions under partial information

Convex functions of quantum states play a key role in quantum physics, with examples ranging from Bell inequalities to von Neumann entropy. However, in experimental scenarios, direct measurements of these functions are often impractical. We address this issue by introducing two methods for determining rigorous confidence bounds for convex functions based on informationally incomplete measurements. Our approach outperforms existing protocols by providing tighter bounds for a fixed confidence level and number of measurements. We evaluate the performance of our methods using both numerical and experimental data. Our findings demonstrate the efficacy of our approach, paving the way for improved quantum state certification in real-world applications

Hydrogen migration at restructuring palladium-silver oxide boundaries dramatically enhances reduction rate of silver oxide.

Heterogeneous catalysts are complex materials with multiple interfaces. A critical proposition in exploiting bifunctionality in alloy catalysts is to achieve surface migration across interfaces separating functionally dissimilar regions. Herein, we demonstrate the enhancement of more than 104 in the rate of molecular hydrogen reduction of a silver surface oxide in the presence of palladium oxide compared to pure silver oxide resulting from the transfer of atomic hydrogen from palladium oxide islands onto the surrounding surface formed from oxidation of a palladium-silver alloy. The palladium-silver interface also dynamically restructures during reduction, resulting in silver-palladium intermixing. This study clearly demonstrates the migration of reaction intermediates and catalyst material across surface interfacial boundaries in alloys with a significant effect on surface reactivity, having broad implications for the catalytic function of bimetallic materials

Can what have we learnt about BCG vaccination in the last 20 years help us to design a better tuberculosis vaccine?

The BCG vaccine will, in 2021, have been in use for 100 years. Much remains to be understood, including the reasons for its variable efficacy against pulmonary tuberculosis in adults. This review will discuss what has been learnt about the BCG vaccine in the last two decades, and whether this new information can be exploited to improve its efficacy, by enhancing its ability to induce either antigen-specific and/or non-specific effects. Many factors affect both the immunogenicity of BCG and its protective efficacy, highlighting the challenges of working with a live vaccine in man, but new insights may enable us to exploit better what BCG can do

Genome-Based Analysis of Extended-Spectrum β-Lactamase-Producing Escherichia coli in the Aquatic Environment and Nile Perch (<i>Lates niloticus</i>) of Lake Victoria, Tanzania

Extended-spectrum β-lactamase (ESBL)-producing bacteria constitute an emerging global health issue with food products being vehicles of transmission and the aquatic environments serving as potential reservoirs. This study aimed to characterize ESBL-producing Escherichia coli in Nile perch and water from Lake Victoria in Tanzania. A total of 180 samples of Nile perch and 60 water samples were screened for ESBL-producing E. coli on MacConkey agar supplemented with 2 μg/ml of cefotaxime and confirmed by blaCTX–M and blaTEM PCR. Antimicrobial resistance was determined by the disk diffusion method, and the ESBL-producing isolates were whole genome sequencing (WGS). ESBL-producing E. coli were detected in eight of the 180 analyzed Nile perch samples, and only one water sample was positive (1.7%, n = 60). Isolates were resistant to sulfamethoxazole–trimethoprim (100%), ampicillin/cloxacillin (100%), erythromycin 72.7% (8/11), tetracycline 90.9% (10/11), and nalidixic acid 63.6% (7/11). This mostly corroborates the resistance genes that they carried for sulfonamides (sul1 and sul2), trimethoprim (dfrA and dfrB), aminoglycosides [aac(3)-IId, strA, and strB], tetracycline [tet(B) and tet(D)], and fluoroquinolones (qepA4). They harbored plasmid replicon types IncF, IncX, IncQ, and Col and carried blaCTX–M–15 and blaTEM–1B genes generally found on the same contigs as the IncF plasmid replicon. Although epidemiologically unrelated, the strains formed three separate sequence type–phylogroup–serotype-specific clusters: C1, C2, and C3. Cluster C1 included five strains (3 to 13 SNPs) belonging to ST167, phylogroup A, and serotype O9:H21; the two C2 strains (11 SNPs) belong to ST156, phylogroup B1, and serotype ONT:H28; and C3 was made up of four strains (SNPs ranged from 4 to 17) of ST636, phylogroup B2, and serotype O45:H7. The common virulence gene gad was reported in all strains. In addition, strains in C2 and C3 possessed iss, lpfA, and nfaE virulence genes, and the vat gene was found only in C3. The present study reports the occurrence of multidrug-resistant ESBL-producing E. coli carrying plasmid-mediated ESBL genes in offshore water and Nile perch in Lake Victoria. Strains formed three clonal clusters of unknown origin. This study reveals that the Lake may serve as reservoir for ESBL-producing bacteria that can be transmitted by fish as a food chain hazard of One-Health concern.Published versio