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A tunable vacuum-ultraviolet (VUV) laser source based on four-wave frequency mixing in xenon is presented. Using seed radiation from two continuous-wave lasers, the system allows for precise control of the VUV frequency and is developed for the resonant laser excitation of the Th-229 nucleus to its low-energy isomeric state. The system is prepared to operate in a wide scanning range from 148 nm to 155 nm. The source produces pulses of 6–10 ns duration with up to 40 µ J energy and is coupled via a vacuum beamline to a linear radiofrequency ion trap. In a first implementation of VUV laser spectroscopy of trapped Th ^+ ions we excite three previously unknown resonance lines near 149 nm wavelength to electronic levels that are close to the Th-229 isomer energy. The resonances are detected and analyzed via fluorescence of the excited Th ^+ ions. An analysis of the lineshape is used to estimate the linewidth of the VUV radiation to be in the range of $\leqslant$ 6 GHz, dominated by phase noise that is enhanced in harmonic generation and in the four-wave mixing process. The prospects for the use of the system in nuclear laser spectroscopy of Th-229 are discussed.

Biological effects of pulsed electrical stimulation (PES) on cells and tissues have been intensively studied with the aim of advancing their biomedical applications. These effects vary significantly depending on PES parameters, cell and tissue types, which can be attributed to the diverse variety of signaling pathways, ion channels, and epigenetic mechanisms involved. The development of new technology platforms, such as nanosecond pulsed electric fields (nsPEFs) with finely tuned parameters, have added further complexity. The present review systematically examines current research progress in various aspects of PES, from physical models to biological effects on cells and tissues, including voltage-sensing domains of voltage-gated channels, pore formation, intracellular components/organelles, and signaling pathways. Emphasis is placed on the complexity of PES parameters and inconsistency of induced biological effects, with the aim of exploring the underlying physical and cellular mechanisms of the physiological effects of electrical stimulation on cells. With chondrogenic differentiation of stem cells and cartilage regeneration as examples, the underlying mechanisms involved were reviewed and analyzed, hoping to move forward towards potential biomedical applications. Hopefully, the present review will inspire more interest in the wider clinical applications of PES and lay the basis for further comprehensive studies in this field.

Based on the parentage identification results using 4 polymorphic short sequence repeats (SSRs) with both parents known, we assessed the accuracy of parentage identification for a single known parent using the same 4 SSRs and 4 other additional SSRs for 2507 Chinese shrimp Fenneropenaeus chinensis recaptured from Jiaozhou Bay in a ‘molecular marker recapture’ program. We detected a high variability in the 4 SSR loci EN0033, RS0622, FCKR002, and FCKR013. The 4 polymorphic loci produced a ≥99.99% cumulative exclusion probability for both known parents. We identified 8 parentage relationships with a logarithm (base 10) of odds (LOD) score of ≥3.0. Similar results were obtained when the 4 additional SSR loci were included. The cumulative exclusion probability decreased to 99.42% for a single known parent using the old 4 SSR loci, which enabled detection of 30 and 44 parentage relationships with a ≥3.0 LOD score for known paternity and maternity, respectively. Inclusion of the additional 4 SSR loci raised, the cumulative exclusion probability to ≥99.99%. However, the number of parentage relationships detected with an LOD score of ≥3.0 was reduced to 8 for the groups with known paternity or maternity, similar to the result obtained with both parents known. In this study, the accuracy of single-parent parentage identification using SSR loci was confirmed. Authentic parentage identification with a single known parent should incorporate both the cumulative exclusion probability and LOD score. Our research provides an alternative method for parentage identification in Chinese shrimp.

The experiment was conducted to evaluate the effects of different dietary vitamin combinations on the egg quality and vitamin concentrations in the eggs of commercial laying hens. A total of 1,800 25-week-old Lohman pink-shell hens were randomly assigned to four dietary vitamin treatments as follows: NRC(1994) level, NRC (1994) level with Hy.D® (25-hydroxy-cholecalciferol), Local level (current average industry level in China) and OVN® level (optimum vitamin nutrition level), with 10 replicates per treatment and 45 layers per replicate. Hens were housed in commercial laying cages with three birds per cage and given ad libitum access to feed. Results showed the hens that received the fortified vitamin levels in the OVN® treatment had a significantly (p

Arbitrary manipulation of the temporal and spectral properties of x-ray pulses at free-electron lasers would revolutionize many experimental applications. At the Linac Coherent Light Source at Stanford National Accelerator Laboratory, the momentum phase-space of the free-electron laser driving electron bunch can be tuned to emit a pair of x-ray pulses with independently variable photon energy and femtosecond delay. However, while accelerator parameters can easily be adjusted to tune the electron bunch phase-space, the final impact of these actuators on the x-ray pulse cannot be predicted with sufficient precision. Furthermore, shot-to-shot instabilities that distort the pulse shape unpredictably cannot be fully suppressed. Therefore, the ability to directly characterize the x-rays is essential to ensure precise and consistent control. In this work, we have generated x-ray pulse pairs via electron bunch shaping and characterized them on a single-shot basis with femtosecond resolution through time-resolved photoelectron streaking spectroscopy. This achievement completes an important step toward future x-ray pulse shaping techniques.

Daptomycin resistance in Staphylococcus aureus has been previously reported, but the development of resistance while on therapy with subsequent clinical failure for endocarditis has been infrequently reported. A case of persistent methicillin-resistant S aureus (MRSA) bacteremia in the setting of right-sided endocarditis in a 38-year-old man with a history of intravenous drug use is presented. He developed de novo resistance to daptomycin during therapy after several courses of antibiotics, with subsequent clinical failure. Isolates were identified by molecular characterization to be community-acquired MRSA 10 (USA300). To the authors’ knowledge, the present case was the first in Canada to involve the de novo development of daptomycin resistance with clinical failure due to MRSA during therapy for endocarditis. Clinicians and microbiologists must be aware of this phenomenon given the implications for treatment and transmission of the strain. It also raises questions regarding the use of daptomycin in settings of heavily pretreated patients with persistent MRSA bacteremia.

BACKGROUND: Intranasal mupirocin or Polysporin Triple (PT) ointment (polymyxin B, bacitracin, gramicidin), in combination with chlorhexidine body washes, have been used for eradicating methicillin-resistant Staphylococcus aureus (MRSA), but no comparative studies have been done.

ABSTRACT The objective of this work was to investigate the effect of feeding conditions on methylation status of FATP1 gene, which is an important candidate gene of Intramuscular fat and important indicator of chicken meat quality. We selected Daninghe (DNH) and Qingjiaoma (QJM) chickens under scatter-feeding and captivity-feeding conditions as experimental animals, and detected the methylation status of FATP1 genes in chicken breast muscle using Bisulfite Sequencing PCR method. The results showed that the methylation level of FATP1 in scatter-fed chicken was lower than in captivity-fed conditions in DNH and QIM chicken breast tissues; DNA methylation in the promoter and exon1 region was demonstrated to negatively regulate the expression of the FATP1 gene. These results suggested that feeding conditions affect the methylation status and expression level of FATP1, thereby affecting the Intramuscular fat content in DNH and QJM chicken breast muscle.