High-performance x-ray source based on graphene oxide-coated Cu2S nanowires grown on copper film.

Full static x-ray computed tomography (CT) technology has enabled higher precision and resolution imaging and has been applied in many applications such as diagnostic medical imaging, industrial inspection and security screening. In this technique, the x-ray source section is mainly composed of a thermionic cathode and electron beam scanning system. However, they have several shortcomings such as limited scanning angle, long response time and large volume. Distributed and programmable cold cathode (i.e. carbon nanotubes, ZnO nanowires (NWs)) field-emission x-ray sources are expected to solve these problems. However, there have been several long-standing challenges to the application of such cold field emitters for x-ray sources, such as the short lifetime and rigorous fabrication process, which have fundamentally prevented their widespread use. Here, we propose and demonstrate a cold field-emission x-ray source based on a graphene oxide (GO)-coated cuprous sulfide nanowire (Cu2S NW/GO) cathode. The proposed Cu2S NW/GO x-ray source provides stable emission (>18 h at a direct voltage of 2600 V) and has a low threshold (4.5 MV m-1 for obtaining a current density of 1 µA cm-2), benefiting from the demonstrated key features such as in situ epitaxy growth of Cu2S NWs on Cu, nanometer-scale sharp protrusions within GO and charge transfer between the Cu2S NWs and GO layer. Our research provides a simple and robust method to obtain a high-performance cold field emitter, leading to great potential for the next generation of x-ray source and CT.

Occupational Stress among Hospital-Based Nurses in Hawai'i during the COVID-19 Pandemic: A Cross-Sectional Survey.

The Coronavirus Disease 2019 (COVID-19) pandemic has caused unprecedented disruption in health care systems and may continue to do so. Nurses, the largest contingent of the nation's health care workforce, have borne the brunt of those disruptions, which have caused increased workload and resultant occupational stress. This study identified differences in nurses' occupational stress by practice specialty, time spent caring for patients with COVID-19, and nurses' demographic characteristics. A descriptive cross-sectional online survey of RNs and APRNs (N=328) was conducted at a Level 1 Trauma Center on the island of O'ahu, Hawai'i in September and October of 2021. Participants completed the 57-item Expanded Nursing Stress Scale (ENSS). Nurses reported an average overall stress score of 2.11 out of 4. The ENSS subscales of workload, patients and their families, inadequate preparation, and uncertainty concerning treatment all had higher mean scores than the total scale. Nurses working in perioperative/procedural areas and obstetrics reported lower overall occupational stress scores than nurses in other specialties. Nurses who spent > 50% of their time caring for patients with COVID-19 reported higher overall occupational stress scores than nurses who spent ≤ 50% of their time caring for patients with COVID-19 (F = 8.21, P < .001). Nurses over the age of 50 reported less stress than their younger counterparts (F = 5.75, P = .004). Understanding how occupational stress impacts acute care nurses can aid employers in allocating resources to address the problem, and thus improve workforce retention.

Organochlorine isotopic pattern-enhanced detection and quantification of triclosan and its metabolites in human serum by ultra-high-performance liquid chromatography/quadrupole time-of-flight/mass spectrometry.

Organochlorines possess special isotopic patterns that obey the chlorine rule. In the case of triclosan (TCS), which contains three chlorine atoms, the isotopic patterns are composed of seven obvious peaks with the calculated masses ranging from 286.9435 to 292.9350 in negative ion mode and with specific isotopic abundance ratios of 100:13.1:97.1:12.6:31.8:4.1:3.6. In this study, mass differences between the calculated and observed m/z values for all isotopic peaks of TCS were less than 3.5 ppm in the analyses of the serum samples by ultra-high-performance liquid chromatography/quadrupole time-of-flight/mass spectrometry (UHPLC-Q-TOF/MS). Combining the characteristics described above, four metabolites were identified as sulfonated TCS, glucuronidated TCS and hydroxylated sulfonated TCS. Several novel MS techniques were applied to improve the sensitivity of quantification of TCS. The limit of detection for TCS in a 250 µL serum sample was 0.05 ng/mL, which was over twenty times lower than values obtained by the LC/triple quadrupole-MS/MS method reported in the literature. The concentration of total TCS (free and conjugated) was quantified to range from 0.15 to 217 ng/mL, whereas free TCS ranged from 0.15 to 10 ng/mL. To the best of our knowledge, this is the first report on the identification of TCS and metabolites in human serum, and it also provides the most sensitive LC/MS approach for the quantification of TCS.

Technique, outcome and changes in prostate dimensions in patients with urinary retention managed by aquablation.

PURPOSE: This study aimed to investigate the functional and urodynamic outcome of Aquablation in patients with acute urinary retention (AUR) on catheters. METHODS: Men aged 50-70 who failed medical treatment of BPO with AUR failing to wean off urethral catheter were recruited to undergo Aquablation. Individuals were assessed pre-operatively and at 3 and 6 months after surgery. The primary outcome was defined by the success rate of weaning off catheter. Secondary outcomes were measured by a change in prostate size, symptom scores and urodynamic parameters. RESULTS: Twenty patients underwent Aquablation between June 2019 and September 2020. Mean duration of the urethral catheter in-situ was 5.9 ± 4.9 weeks and mean prostate size of the cohort pre-operatively was 60.8 ± 15.8 cc. A second pass Aqaublation treatment was performed in 14 patients. Five patients failed to wean off the catheter on the first attempt after surgery, requiring another attempt 1 week later which were all successful. At 3 months after the operation, a significant reduction in prostate volume was observed (60.8 ± 15.8 cc vs 24.9 ± 10.3 cc, p < 0.001). No change in international index of erectile function (IIEF) was found (baseline: 16.1 ± 5.8; 3-month: 14.9 ± 6.4; p = 0.953). Mean bladder outlet obstruction index was 14.2 ± 23.0 at 6 months upon urodynamic assessment with 75% of patients had a resolution of detrusor overactivity. Reduction in prostate length was found to be more significant than a reduction in width and height after Aquablation (R = 0.693, p = 0.039). CONCLUSION: From the early data of a single centre, Aquablation was shown to provide a consistent improvement in symptoms, uroflowmetry and urodynamic parameters in patient with a urethral catheter. Results from our study suggest that improvement from Aquablation is reproducible in patients with AUR.

Maternally inherited Leigh syndrome: an unusual cause of infantile apnea.

INTRODUCTION: Leigh Syndrome is an uncommon cause of infantile apnea. CASE SUMMARY: We report a 5-month-old girl with sudden respiratory arrest followed by episodic hyper- and hypo-ventilation, encephalopathy, and persistent lactic acidosis. Computed tomography of the brain revealed symmetric low densities over the basal ganglia, internal capsule, thalami, and midbrain. Cardiac echocardiogram was suggestive of hypertrophic cardiomyopathy. DISCUSSION: Diagnosis of Leigh syndrome due to T8993G mutation was confirmed with polymerase chain reaction and direct DNA sequencing of mitochondrial genome. To our knowledge, this is the first report of proven maternally inherited Leigh syndrome in Hong Kong.

WITHDRAWN: Novel missense mutation (Y24H) in the G6PT1 gene causing glycogen storage disease type 1b.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Erratum to: Mutational analysis of 65 Wilson disease patients in Hong Kong Chinese: Identification of 17 novel mutations and its genetic heterogeneity.

The correct name of the eighth author should be given as Sik-To Lai, not Jak-Yiu Lai.

Lattice Dynamics and Thermal Stability of Cubic-Phase CsPbI3 Quantum Dots.

Cubic-phase CsPbI3 quantum dots (QDs) have been recently synthesized with merits of excellent optoelectronic performance. However, vital properties of cubic CsPbI3 including lattice dynamics and stability at high temperature remain poorly explored. We fabricate cubic CsPbI3 QDs and study their lattice dynamic and thermal stability to 700 K. We obtain Raman modes of cubic CsPbI3 QDs from 300 to 500 K at ultra-low-frequency range down to 15 cm-1, consistent with first-principles calculations. Above 550 K, the modification of Raman features suggests sample degradation. Consistently, temperature-dependent photoluminescence measurements indicate the absence of other luminescence phases up to 700 K. With increasing temperature, the CsPbI3 QD photoluminescence peak has a blue shift with exponentially decreasing intensity, showing faster electronic degradation than structural degradation. Our work provides detailed investigation of CsPbI3 QD lattice dynamics, band gap, and their high-temperature behavior, potentially useful for their emerging optoelectronic applications.

Genome-wide detection of allelic imbalance in renal cell carcinoma using high-density single-nucleotide polymorphism microarrays.

OBJECTIVE: Renal cell carcinoma (RCC) appears in both a sporadic form and a hereditary form. Eighty-five percent of sporadic RCCs are of the clear-cell histologic type. The cytogenetic analysis of RCCs has revealed several recurring sites of chromosomal aberrations (non-disjunction, deletion or mitotic recombination) including segments of loss of heterozygosity (LOH) identifiable by polymorphic markers. In this pilot study, we performed a comprehensive genome-wide scan to identify LOH sites of RCCs in three Chinese patients using high-density single-nucleotide polymorphism microarrays (HuSNP arrays). DESIGN AND METHODS: Three sporadic clear-cell RCCs specimens were diagnosed histologically. Tumor genomic DNA was extracted from paraffin-embedded sections after microdissection to avoid gross contamination by non-tumor cells. Germline DNA was obtained from paired normal adjacent tissues. Affymetrix HuSNP mapping assay was performed according to the manufacturer's instructions. RESULTS: Using high-density single-nucleotide polymorphism microarrays, we were able to identify the previously described and new LOH sites in RCCs of the three Chinese patients. CONCLUSION: The high-density single-nucleotide polymorphism microarrays and assays offer significant operating cost benefits in sample preparation, processing, and data analysis for identification of LOH sites in cancer samples. In contrast to the typical microsatellite genotyping strategy, the entire genome scan is completed in one experiment taking less than 2 days.

Missense mutation Leu72Pro located on the carboxyl terminal amphipathic helix of apolipoprotein C-II causes familial chylomicronemia syndrome.

BACKGROUND: Chylomicronemia syndrome can be caused by 2 autosomal recessive disorders - lipoprotein lipase (LPL) deficiency and apolipoprotein C-II (apo C-II) deficiency. METHODS: We described 2 siblings with chylomicronemia syndrome of a consanguineous family. To determine the molecular basis of chylomicronemia syndrome in this family, we performed direct DNA sequencing of the LPL and APOC2 genes of the proband. RESULTS: A novel homozygous mutation, Leu72Pro, in the APOC2 gene was found in both siblings whereas their parents were carriers. No LPL mutations were detected in the siblings. Apo C-II contains 3 amphipathic alpha helices; the C-terminal alpha helix is composed of residues 64 to 74. Substitution of residue 72 from a helix former leucine to a helix breaker, proline, is predicted to change the secondary structure of the C-terminal helix and subsequently alter the interaction between apo C-II and LPL. CONCLUSIONS: To our knowledge, Leu72Pro is the first missense mutation identified in the C-terminal of apo C-II. The result is consistent with the current biochemical and structural findings that the C-terminal helix of apo C-II is important for activation of LPL.

Galactorrhea-a strong clinical clue towards the diagnosis of neurotransmitter disease.

Two siblings from a Hong Kong Chinese family are diagnosed to have heterozygous mutation in tyrosine hydroxylase gene-a novel mutation R169X and the common Dutch mutation R233H. Presented with developmental delay and dystonia before 6 months of age, both had hyperprolactinemia with persistent galactorrhea present in the elder brother since birth. Serum prolactin level is a good screening test for those suspected of underlying neurotransmitter diseases. To our knowledge, this is the first Chinese family diagnosed with such condition. Clinicians must be aware of this rare disease especially in those unexplained 'cerebral palsy' like children.

Earth Abundant Element Type I Clathrate Phases.

Earth abundant element clathrate phases are of interest for a number of applications ranging from photovoltaics to thermoelectrics. Silicon-containing type I clathrate is a framework structure with the stoichiometry A8-xSi46 (A = guest atom such as alkali metal) that can be tuned by alloying and doping with other elements. The type I clathrate framework can be described as being composed of two types of polyhedral cages made up of tetrahedrally coordinated Si: pentagonal dodecahedra with 20 atoms and tetrakaidecahedra with 24 atoms in the ratio of 2:6. The cation sites, A, are found in the center of each polyhedral cage. This review focuses on the newest discoveries in the group 13-silicon type I clathrate family: A8E8Si38 (A = alkali metal; E = Al, Ga) and their properties. Possible approaches to new phases based on earth abundant elements and their potential applications will be discussed.

DNA-based diagnosis of xeroderma pigmentosum group C by Whole-genome scan using single-nucleotide polymorphism microarray.

In this study, we have established the molecular basis of xeroderma pigmentosum (XP) in two unrelated Chinese families. In the first patient with consanguineous parents, we mapped the disease-causing locus XPC using single-nucleotide polymorphism microarray. Mutational analysis of the XPC gene showed that the patient is homozygous for a nonsense mutation, E149X. After developing DNA-based diagnosis of XPC, we screened another XP patient for XPC mutations. We found that the second patient is a compound heterozygote of 1209delG and Q554X in this gene. These are the first XPC-causing mutations identified in Chinese patients.

DNA-based diagnosis of thyroid hormone resistance syndrome: a novel THRB mutation associated with mild resistance to thyroid hormone.

BACKGROUND: Thyroid hormones govern a wide range of metabolic processes in the body via thyroid hormone receptors (TR). We report a patient with mild resistance to thyroid hormone who was initially misdiagnosed and treated as having thyrotoxicosis. METHODS: We used direct DNA sequencing of the THRB gene. RESULTS: We identified a novel missense mutation, I276L, located in exon 8 of the gene. The mutation is located in cluster 3 of the ligand-binding domain, a protein domain associated with resistance to thyroid hormone. CONCLUSION: DNA-based diagnosis of thyroid hormone resistance syndrome is simple, reliable, and economical compared to traditional biochemical tests. Once the mutation is identified, targeted screening for the whole family can be performed and the unnecessary use of anti-thyroid drugs or thyroidectomy can be avoided.

Novel missense mutation in the CASR gene in a Chinese family with familial hypocalciuric hypercalcemia.

BACKGROUND: Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant disorder characterized by asymptomatic and non-progressive hypercalcemia resulting from loss-of-function mutations of the CASR (calcium-sensing receptor) gene located on chromosome 3, or from mutations in two mapped but unidentified genes located on chromosome 19. METHODS: We report a middle-aged woman incidentally found to have FHH. To determine the molecular basis of FHH in this Chinese family, we performed direct DNA sequencing of the CASR gene of the proband. RESULTS: We found that the proband is heterozygous for a novel missense mutation P798T, confirming the diagnosis of FHH. Family screening showed that all of the offspring with biochemical features of FHH have the P798T mutation. The mutation, P798T, is located in the third intracellular loop of the CASR, possibly affecting the downstream calcium sensing pathway and therefore inactivating the receptor function. CONCLUSIONS: The molecular basis of FHH in a Chinese family was established. The developed mutation detection assay provides a reliable method for identifying FHH carriers.

Novel mutations in the BCHE gene in patients with no butyrylcholinesterase activity.

BACKGROUND: Butyrylcholinesterase (BCHE) deficiency is characterized by prolonged apnea after the use of certain muscle relaxants with the genetic defect lying in the BCHE gene. METHODS: Two Chinese patients with no serum BCHE activity were studied. The BCHE genes were screened for mutations by polymerase chain reaction and direct DNA sequencing. RESULTS: Of the four mutations detected, two novel mutations were identified in the two patients, i.e., F474L, and an insertion of an adenine between nucleotide positions 395 and 396. This information was used to screen the immediate families of the patients for carrier status. CONCLUSIONS: We established the molecular basis of butyrylcholinesterase deficiency in two Chinese patients. The developed mutation detection assay provides a reliable method for identifying mutant BCHE carriers.

Non-sentinel lymph node metastases in breast cancer patients with metastatic sentinel nodes.

BACKGROUND: Sentinel lymph node biopsy (SLNB) has been shown to be relatively accurate in axillary nodal staging in breast cancer. In more than half of the patients with metastatic sentinel lymph node (SLN), the SLN was the only lymph node involved in the axilla. METHODS: A retrospective analysis was performed for those female Chinese breast cancer patients who underwent SLNB. All patients had axillary dissection after SLNB. Those patients with metastatic SLN were selected for analysis. Various tumour factors and SLN factors were analysed to study the association with residual lymph node metastasis. RESULTS: A total of 139 SLNB was performed. The success rate of SLN localization, false negative rate and accuracy were 92%, 9% and 95%, respectively. Fifty-five patients had metastases in the SLN. In 38 patients (69%), SLN was the only lymph node involved in the axilla. Tumours <3 cm, a single metastatic SLN, presence of micro metastases and the absence of extracapsular spread in the SLN were associated with the absence of metastasis in the non-sentinel lymph nodes. CONCLUSION: Sentinel lymph node biopsy is accurate in the nodal staging of Chinese breast cancer patients. Several factors such as tumour <3 cm, a single metastatic SLN, micro metastases and the absence of extracapsular spread in the sentinel node(s) are useful predictors for the absence of residual disease in the axilla. With further studies and verification, these factors may prove to be important in determining which patients with metastatic SLN will require further axillary treatment. Until such information is available, axillary dissection should be performed when positive sentinel nodes are found.

Novel mutations of the AGXT gene causing primary hyperoxaluria type 1.

BACKGROUND: Primary hyperoxaluria type 1 (PH1), an inherited cause of nephrolithiasis, is due to a functional defect of the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT). A definitive PH1 diagnosis can be established by analyzing AGT activity in liver tissue or mutation analysis of the AGXT gene. METHODS: The molecular basis of PH1 in three Chinese patients, two with adult-onset and one with childhood-onset recurrent nephrolithiasis, was established by analyzing the entire AGXT gene. RESULTS: Three novel mutations (c2T>C, c817insAG and c844C>T) and two previously reported mutations (c33insC and 679-IVS6+2delAAgt) were identified. c2T>C converts the initiation codon from ATG to ACG, which predicts significant reduction, if not complete abolition, of protein translation. c817insAG leads to a frameshift and changes the amino acid sequence after codon 274. c844C>T changes glutamine at codon 282 to a termination codon, resulting in protein truncation. CONCLUSIONS: This is the first report describing AGXT gene mutations in Chinese patients with PH1. AGXT genotypes cannot fully explain the clinical heterogeneity of PH1, and other factors involved in disease pathogenesis remain to be identified. Our experience emphasizes the importance of excluding PH1 in patients with recurrent nephrolithiasis to avoid delay or inappropriate management.

Novel mitochondrial 16S rRNA mutation, 3200T-->C, associated with adult-onset type 2 diabetes.

OBJECTIVE: To investigate the role of a potential diabetes-related mitochondrial region, which includes two previously reported mutations, 3243A-->G and 3316G-->A, in Chinese patients with adult-onset type 2 diabetes. METHODS: A total of 277 patients and 241 normal subjects were recruited for the study. Mitochondrial nt 3116 - 3353, which spans the 16S rRNA, tRNA(leu(UUR)) and the NADH dehydrogenase 1 gene, were detected using polymerase chain reaction (PCR), direct DNA sequencing, PCR-restriction fragment length polymorphism and allele-specific PCR. Variants were analyzed by two-tailed Fisher exact test. The function of the variants in 16S rRNA were predicted for minimal free energy secondary structures by RNA folding software mfold version 3. RESULTS: Four homoplasmic nucleotide substitutions were observed, 3200T-->C, 3206C-->T, 3290T-->C and 3316G-->A. Only the 3200T-->C mutation is present in the diabetic population and absent in the control population. No statistically significant associations were found between the other three variants and type 2 diabetes. The 3200T-->C and 3206C-->T nucleotide substitutions located in 16S rRNA are novel variants. The 3200T-->C caused a great alteration in the minimal free energy secondary structure model while the 3206C-->T altered normal 16S rRNA structure little. CONCLUSIONS: The results suggest that the 3200T-->C mutation is linked to the development of type 2 diabetes, but that the other observed mutations are neutral. In contrast to the Japanese studies, the 3316G-->A does not appear to be related to type 2 diabetes.