Sub-surface Imaging of Porous GaN Distributed Bragg Reflectors via Backscattered Electrons.

In this article, porous GaN distributed Bragg reflectors (DBRs) were fabricated by epitaxy of undoped/doped multilayers followed by electrochemical etching. We present backscattered electron scanning electron microscopy (BSE-SEM) for sub-surface plan-view imaging, enabling efficient, non-destructive pore morphology characterization. In mesoporous GaN DBRs, BSE-SEM images the same branching pores and Voronoi-like domains as scanning transmission electron microscopy. In microporous GaN DBRs, micrographs were dominated by first porous layer features (45 nm to 108 nm sub-surface) with diffuse second layer (153 nm to 216 nm sub-surface) contributions. The optimum primary electron landing energy (LE) for image contrast and spatial resolution in a Zeiss GeminiSEM 300 was approximately 20 keV. BSE-SEM detects porosity ca. 295 nm sub-surface in an overgrown porous GaN DBR, yielding low contrast that is still first porous layer dominated. Imaging through a ca. 190 nm GaN cap improves contrast. We derived image contrast, spatial resolution, and information depth expectations from semi-empirical expressions. These theoretical studies echo our experiments as image contrast and spatial resolution can improve with higher LE, plateauing towards 30 keV. BSE-SEM is predicted to be dominated by the uppermost porous layer's uppermost region, congruent with experimental analysis. Most pertinently, information depth increases with LE, as observed.

Assessment of Wound-Related Pain Experiences of Patients With Chronic Wounds: A Multicenter Cross-Sectional Study in Eastern China.

PURPOSE: The primary aims of this study were to evaluate the prevalence of wound-related pain (WRP) in patients with chronic wounds and assess the use of pain relief measures. DESIGN: A cross-sectional study. SUBJECTS AND SETTING: A convenience sample of patients with chronic wounds was recruited from outpatient clinics of 12 hospitals covering 7 of 13 cities in the Jiangsu province located in eastern China from July 10 to August 25, 2020. The sample comprised 451 respondents, and their mean age was 54.85 (SD 19.16) years; 56.1% (253/451) patients were male. METHODS: An investigator-designed questionnaire was used to collect pain-related information from patients. The questionnaire consisted of 4 parts: (1) basic demographic and clinical information (patient and wound characteristics); (2) wound baseline pain; (3) wound-related procedural pain and pain relief method; and (4) the effect of WRP on the patient. Pain was assessed using the Numerical Rating Scale (NRS) scored from 0 (no pain) to 10 (worst pain). Severity of pain was based on NRS scores' classification as mild (1-3), moderate (4-6), and severe (7-10). The survey was conducted from July 10 to August 25, 2020. Participants were instructed on use of the NRS and then completed the questionnaire following dressing change independently. RESULTS: The 3 most common types of chronic wounds were traumatic ulcers, surgical wounds, and venous leg ulcers. The 3 most prevalent locations were lower limbs, feet, and thorax/abdomen. Of all patients, 62.5% (282/451) and 93.8% (423/451) patients experienced wound baseline pain and wound-related procedural pain, respectively. The mean score of wound baseline pain was 3.76 (SD 1.60) indicating moderate pain. During wound management, the highest pain score was 6.45 (SD 2.75) indicating severe pain; the most severe pain scores were associated with debridement. The use of drugs to relieve wound pain was low, while the use of nondrug-based analgesia was relatively high. Because of WRP, patients with chronic wounds feared dressing changes, hesitated to move, and showed a decline in sleep quality. CONCLUSIONS: Wound baseline pain and wound-related procedural pain were very common in patients with chronic wounds. In the future, targeted intervention plans should be developed by combining drug-based and nondrug-based analgesia according to pain severity.

Psychometric evaluation of the Wound-QoL questionnaire to assess health-related quality of life in Chinese people with chronic wounds.

Chronic wounds are very common wound types in clinics which have a prolonged and painful healing process. Chronic wounds affect health-related quality of life (HRQoL) on patients. However, there is no specific instrument to measure the HRQoL in Chinese patients with chronic wounds. Wound-QoL is a questionnaire targeted the experience of health-related life to patients with chronic wounds. The study aims to translate and cross-culturally adapt the Wound-QoL into Chinese and to evaluate its psychometric properties (validity, reliability, floor, and ceiling effect) in a convenience sample of 203 Chinese outpatients with chronic wounds. Reliability was good, with internal consistency of 0.798-0.960 and test-retest reliability of 0.720-0.838. Criterion-related validity was assessed by the correlation coefficient between Wound-QoL and generic European QoL instrument- EQ-5D-5L, which was found statistically significant (P<.001). No signs of floor or ceiling effect could be detected. Further, confirmatory factor analysis (CFA) was used to verify the reliability and validity of the instrument in this study. In conclusion, the Chinese Wound-QoL is a valid and reliable tool for measuring HRQoL in populations with chronic wounds.

[Purification of the recombinant Com1 and adaA of Coxiella burnetii and identification of the antigenicity].

Objective To express and purify two kinds of antigens of Coxiella burnetii (C. burnetii), the main outer membrane protein Com1 and the acute disease antigen A (adaA), in prokaryotic expression system and to validate the two recombinant antigens by mass spectrometry and identify their antigenicity. Methods The gene sequences encoding Com1 and adaA were separately synthesized and constructed into the prokaryotic expression vector pET-20b(+). The constructed vectors were transformed into E.coli BL21(DE3), and the recombinant proteins were induced by IPTG. The recombinant Com1 and adaA were purified by His affinity chromatography and identified by mass spectrometry. The immunoreactivity of the two antigens was identified by Western blot analysis using Q fever positive bovine serum. Results The expression vectors pET-20b(+)-Com1 and pET-20b(+)-adaA were constructed and the recombinant Com1 and adaA were expressed and purified in a soluble form. High-purity recombinant Com1 and adaA were obtained after purification, and the SDS-PAGE showed that their relative molecular masses were Mr 27 000 and 25 000, respectively. The mass spectrometry confirmed the recombinant proteins were Com1 and adaA of C. burnetii. Both of the recombinant Com1 and adaA were able to react with the Q fever positive bovine serum in Western blotting, and the corresponding bands were in accordance with the SDS-PAGE. Conclusion We obtained high-purity Com1 and adaA in a soluble form and confirmed their immunoreactivity.

Identification of common immunodominant antigens of Eimeria tenella, Eimeria acervulina and Eimeria maxima by immunoproteomic analysis.

Clinical chicken coccidiosis is mostly caused by simultaneous infection of several Eimeria species, and host immunity against Eimeria is species-specific. It is urgent to identify common immunodominant antigen of Eimeria for developing multivalent anticoccidial vaccines. In this study, sporozoite proteins of Eimeria tenella, Eimeria acervulina and Eimeria maxima were analyzed by two-dimensional electrophoresis (2DE). Western bot analysis was performed on the yielded 2DE gel using antisera of E. tenella E. acervulina and E. maxima respectively. Next, the detected immunodominant spots were identified by comparing the data from MALDI-TOF-MS/MS with available databases. Finally, Eimeria common antigens were identified by comparing amino acid sequence between the three Eimeria species. The results showed that analysis by 2DE of sporozoite proteins detected 629, 626 and 632 protein spots from E. tenella, E. acervulina and E. maxima respectively. Western bot analysis revealed 50 (E. tenella), 64 (E. acervulina) and 57 (E. maxima) immunodominant spots from the sporozoite 2DE gels of the three Eimeria species. The immunodominant spots were identified as 33, 27 and 25 immunodominant antigens of E. tenella, E. acervulina and E. maxima respectively. Fifty-four immunodominant proteins were identified as 18 ortholog proteins among the three Eimeria species. Finally, 5 of the 18 ortholog proteins were identified as common immunodominant antigens including elongation factor 2 (EF-2), 14-3-3 protein, ubiquitin-conjugating enzyme domain-containing protein (UCE) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). In conclusion, our results not only provide Eimeria sporozoite immunodominant antigen map and additional immunodominant antigens, but also common immunodominant antigens for developing multivalent anticoccidial vaccines.

Identification of immune protective genes of Eimeria maxima through cDNA expression library screening.

BACKGROUND: Eimeria maxima is one of the most prevalent Eimeria species causing avian coccidiosis, and results in huge economic loss to the global poultry industry. Current control strategies, such as anti-coccidial medication and live vaccines have been limited because of their drawbacks. The third generation anticoccidial vaccines including the recombinant vaccines as well as DNA vaccines have been suggested as a promising alternative strategy. To date, only a few protective antigens of E. maxima have been reported. Hence, there is an urgent need to identify novel protective antigens of E. maxima for the development of neotype anticoccidial vaccines. METHODS: With the aim of identifying novel protective genes of E. maxima, a cDNA expression library of E. maxima sporozoites was constructed using Gateway technology. Subsequently, the cDNA expression library was divided into 15 sub-libraries for cDNA expression library immunization (cDELI) using parasite challenged model in chickens. Protective sub-libraries were selected for the next round of screening until individual protective clones were obtained, which were further sequenced and analyzed. RESULTS: Adopting the Gateway technology, a high-quality entry library was constructed, containing 9.2 × 106 clones with an average inserted fragments length of 1.63 kb. The expression library capacity was 2.32 × 107 colony-forming units (cfu) with an average inserted fragments length of 1.64 Kb. The expression library was screened using parasite challenged model in chickens. The screening yielded 6 immune protective genes including four novel protective genes of EmJS-1, EmRP, EmHP-1 and EmHP-2, and two known protective genes of EmSAG and EmCKRS. EmJS-1 is the selR domain-containing protein of E. maxima whose function is unknown. EmHP-1 and EmHP-2 are the hypothetical proteins of E. maxima. EmRP and EmSAG are rhomboid-like protein and surface antigen glycoproteins of E. maxima respectively, and involved in invasion of the parasite. CONCLUSIONS: Our results provide a cDNA expression library for further screening of T cell stimulating or inhibiting antigens of E. maxima. Moreover, our results provide six candidate protective antigens for developing new vaccines against E. maxima.

Highly Enhanced Thermoelectric Properties of Bi/Bi2S3 Nanocomposites.

Bismuth sulfide (Bi2S3) has been of high interest for thermoelectric applications due to the high abundance of sulfur on Earth. However, the low electrical conductivity of pristine Bi2S3 results in a low figure of merit (ZT). In this work, Bi2S3@Bi core-shell nanowires with different Bi shell thicknesses were prepared by a hydrothermal method. The core-shell nanowires were densified to Bi/Bi2S3 nanocomposite by spark plasma sintering (SPS), and the structure of the nanowire was maintained as the nanocomposite due to rapid SPS processing and low sintering temperature. The thermoelectric properties of bulk samples were investigated. The electrical conductivity of a bulk sample after sintering at 673 K for 5 min using Bi2S3@Bi nanowire powders prepared by treating Bi2S3 nanowires in a hydrazine solution for 3 h is 3 orders of magnitude greater than that of a pristine Bi2S3 sample. The nanocomposite possessed the highest ZT value of 0.36 at 623 K. This represents a new strategy for densifying core-shell powders to enhance their thermoelectric properties.