Estimating the burden of foodborne gastroenteritis due to nontyphoidal Salmonella enterica, Shigella and Vibrio parahaemolyticus in China

To estimate the incidence of foodborne gastroenteritis caused by nontyphoidal Salmonella enterica, Shigella, and Vibrio parahaemolyticus in China, population surveys and sentinel hospital surveillance were implemented in six provinces from July 2010 to July 2011, and a multiplier calculation model for the burden of disease was constructed. The multiplier for salmonellosis and V. parahaemolyticus gastroenteritis was estimated at 4,137 [95% confidence interval (CI) 2,320–5,663], and for shigellosis at 4,356 (95% CI 2,443–5,963). Annual incidence per 100,000 population was estimated as 245 (95% CI 138–336), 67 (95% CI 38–92), and 806 (95% CI 452–1,103) for foodborne salmonellosis, shigellosis, and V. parahaemolyticus gastroenteritis, respectively, indicating that foodborne infection caused by these three pathogens constitutes an important burden to the Chinese healthcare system. Continuous implementation of active surveillance of foodborne diseases, combined with multiplier models to estimate disease burden, makes it possible for us to better understand food safety status in China.

A cluster of mesopontine GABAergic neurons suppresses REM sleep and curbs cataplexy

Physiological rapid eye movement (REM) sleep termination is vital for initiating non-REM (NREM) sleep or arousal, whereas the suppression of excessive REM sleep is promising in treating narcolepsy. However, the neuronal mechanisms controlling REM sleep termination and keeping sleep continuation remain largely unknown. Here, we reveal a key brainstem region of GABAergic neurons in the control of both physiological REM sleep and cataplexy. Using fiber photometry and optic tetrode recording, we characterized the dorsal part of the deep mesencephalic nucleus (dDpMe) GABAergic neurons as REM relatively inactive and two different firing patterns under spontaneous sleep–wake cycles. Next, we investigated the roles of dDpMe GABAergic neuronal circuits in brain state regulation using optogenetics, RNA interference technology, and celltype-specific lesion. Physiologically, dDpMe GABAergic neurons causally suppressed REM sleep and promoted NREM sleep through the sublaterodorsal nucleus and lateral hypothalamus. In-depth studies of neural circuits revealed that sublaterodorsal nucleus glutamatergic neurons were essential for REM sleep termination by dDpMe GABAergic neurons. In addition, dDpMe GABAergic neurons efficiently suppressed cataplexy in a rodent model. Our results demonstrated that dDpMe GABAergic neurons controlled REM sleep termination along with REM/NREM transitions and represented a novel potential target to treat narcolepsy.

Oxocarbon Anions Templated in Silver Clusters

Three types of oxocarbon anions as templates were used to synthesize high-nuclear silver clusters, [Ag₁₆(C₂O₄){S₂P(OEt)₂}₁₂]₂(PF₆)₄ (1), [Ag₁₆(C₄O₄){S₂P(OEt)₂}₁₂]₂(PF₆)₄ (2), and [Ag₃₂(S)₂(C₅O₅)₂{S₂P(OEt)₂}₂₂](PF₆)₂ (3), and characterized by multi-NMR spectroscopy and X-ray crystallography. As the template size increases, the shape and size of the clusters change accordingly. The template effect in high-nuclear silver clusters has been investigated in this work.

SARS-CoV-2 testing, infection and outcomes among Ontario physicians: a descriptive population-based cohort study

BACKGROUND

Health care workers have a higher risk of acquiring SARS-CoV-2 infection than the general population. Our study reports on SARS-CoV-2 testing, infection and associated outcomes in Ontario physicians before SARS-CoV-2 vaccination became available on Dec. 14, 2020.

METHODS

We conducted a descriptive, population-based cohort study of physicians in Ontario, Canada, from Jan. 25 to Dec. 31, 2020. We included physicians and postgraduate medical trainees who were residents of Ontario and registrants with the College of Physicians and Surgeons of Ontario during the study period. We examined the proportion of physicians tested for SARS-CoV-2 infection, the proportion who tested positive, and how testing and infections varied by certain physician characteristics. We reported on clinical outcomes associated with infection, including hospital admission and death.

RESULTS

Of 41 208 physicians (mean age 47 yr; 56.1% male), 19 116 (46.4%) were tested at least once for SARS-CoV-2 infection; 358 tested positive (0.9%). No physicians died within 30 days of testing positive; however, 20/358 (5.6%) were admitted to hospital. By specialty, the proportion tested was highest among postgraduate medical trainees (2531/4125 [61.4%]), emergency physicians (281/478 [58.8%]), infectious disease physicians (33/67 [49.3%]) and family physicians (8857/18 553 [47.7%]). The proportion who tested positive was highest among internal medicine physicians (44/3499 [1.3%]), postgraduate medical trainees (47/4125 [1.1%]) and family physicians (171/18 553 [0.9%]). Of 2290 physicians who worked in long-term care, 1636 (71.4%) were tested and 25 (1.1%) tested positive.

INTERPRETATION

During the prevaccination period of the COVID-19 pandemic in Ontario, nearly half of all physicians in the province were tested at least once for SARS-CoV-2 infection, 0.9% tested positive and none died. These findings may reflect the public health measures that were implemented in the province during this period.

Heart rate variability in patients with anxiety disorders: A systematic review and meta-analysis

AIMS

Patients with anxiety disorders (AD) have been found to have lower heart rate variability (HRV) than healthy individuals in some studies, but this was inconsistent. Furthermore, the influence of distinct diagnoses, study design, and demographic factors on the results was not comprehensively examined.

METHODS

We gathered studies comparing HRV in patients with AD and in healthy controls. The parasympathetic activity in the hierarchical order principle was adopted in the main analysis. We adopted the random effects model to calculate the standardized mean difference.

RESULTS

Of the 7805 screened studies, 99 were included in the quantitative analysis, with a total of 4897 AD patients and 5559 controls finally entered the meta-analysis. AD patients had a significantly lower resting-state HRV for parasympathetic activity compared to control (Hedges' g = -0.3897). For the diagnostic subgroup analysis relative to the controls, resting-state HRV was significantly lower in post-traumatic stress disorder, panic disorder, generalized anxiety disorder, and social anxiety disorder patients. HRV reactivity (all reactivity data, data on physiological challenge, and psychological challenge) did not show significant inter-group differences between AD patients and healthy subjects.

CONCLUSIONS

The results supported that patients with AD had significantly lower resting-state HRV than the healthy population, but no alterations were found for HRV reactivity.

Hydride-Containing Eight-Electron Pt/Ag Superatoms: Structure, Bonding, and Multi-NMR Studies

Recent reports on hydride-doped noble metal nanoclusters strongly suggest that the encapsulated hydride is a part of the superatom core, but no accurate location of the hydride could be experimentally proved, so far. We report herein a hydride-doped eight-electron platinum/silver alloy nanocluster in which the position of four-coordinated hydride was determined by neutron diffraction for the first time. X-ray structures of [PtHAg₁₉(dtp/desp)₁₂] (dtp = S₂P(OⁿPr)₂, 1; dsep = Se₂P(OⁱPr)₂, 2) describe a central platinum hydride (PtH) unit encapsulated within a distorted Ag₁₂ icosahedron, the resulting (PtH)@Ag₁₂ core being stabilized by an outer sphere made up of 7 capping silver atoms and 12 dichalcogenolates. Solid-state structures of 1 and 2 differ somewhat in the spatial configuration of their outer spheres, resulting in overall different symmetries, C₁ and C₃, respectively. Whereas the multi-NMR spectra of 2 in solution at 173 K reveal that the structure of C₃ symmetry is the predominant one, ¹H and ¹⁹⁵Pt NMR spectra of 1 at the same temperature disclose the presence of isomers of both C₁ and C₃ symmetry. DFT calculations found both isomers to be very close in energy, supporting the fact that they co-exist in solution. They also show that the [PtH@Ag₁₂]⁵⁺ kernel can be viewed as a closed-shell superatomic core, the μ₄-hydride electron contributing to its eight-electron count. On the other hand, the 1s(H) orbital contributes only moderately to the superatomic orbitals, being mainly involved in the building of a Pt-H bonding electron pair with the 5d_z²(Pt) orbital.

Homoleptic Silver-Rich Trimetallic M20 Nanocluster

Two silver-rich M₂₀ alloy nanoclusters (NCs), [Cu_3.5Ag_16.5{S₂P(OⁿPr)₂}₁₂] (1) and [Cu_2.5AuAg_16.5{S₂P(OⁿPr)₂}₁₂] (2), were synthesized and fully characterized by electrospray ionization mass spectrometry, NMR spectroscopy, and X-ray crystallography. Cluster 2, the first structurally characterized trimetallic M₂₀ NC, was produced by doping one Au atom into a bimetallic M₂₀ NC. Structural analyses showed the preferred positions of Group 11 metals in the yielded M₂₀ NCs. Their antioxidation ability has been investigated, and the time-dependent UV-vis spectrum shows that the presence of Cu^I atoms in structures 1 and 2 can improve the antioxidant ability.

The Effect of Heavy Fe-Doping on 3D Growth Mode and Fe Diffusion in GaN for High Power HEMT Application

The high electron mobility transistor (HEMT) structures on Si (111) substrates were fabricated with heavily Fe-doped GaN buffer layers by metalorganic chemical vapor deposition (MOCVD). The heavy Fe concentrations employed for the purpose of highly insulating buffer resulted in Fe segregation and 3D island growth, which played the role of a nano-mask. The in situ reflectance measurements revealed a transition from 2D to 3D growth mode during the growth of a heavily Fe-doped GaN:Fe layer. The 3D growth mode of Fe nano-mask can effectively annihilate edge-type threading dislocations and improve transfer properties in the channel layer, and consequently decrease the vertical leakage current by one order of magnitude for the applied voltage of 1000 V. Moreover, the employment of GaN:C film on GaN:Fe buffer can further reduce the buffer leakage-current and effectively suppress Fe diffusion.

Striatal neurons expressing dopamine D1 receptor promote wakefulness in mice

Patients with Parkinson's disease (PD) suffer from severe sleep disorders. Pathophysiology of the basal ganglia (BG) underlies PD, and the dorsal striatum represents the major input pathway of the BG. However, the roles and mechanisms of the dorsal striatum in controlling sleep-wake cycles remain unknown. To demonstrate the contribution of dopamine D₁ receptor (D₁R)-positive neurons within the dorsal striatum in promoting wakefulness, we combined optogenetic manipulations and fiber photometry with electroencephalography/electromyography recording in D₁R-Cre mice. As a result, optogenetic activation of striatal D₁R neurons induced immediate transitions from non-rapid eye movement (NREM) sleep to wakefulness, whereas inhibition of striatal D₁R neurons attenuated wakefulness by chemogenetics. Multi-channel fiber photometry recordings revealed that the activity of striatal D₁R neurons synchronized with that of BG upstreams, namely the prefrontal cortex and mediodorsal thalamus, in terms of immediate increase in activity during NREM-to-wake transitions and rapid decease during wake-to-NREM transitions. Further optogenetic manipulations revealed a prominent contribution of striatal D₁R neurons in control of wakefulness by upstream, corticostriatal, thalamostriatal, and nigrostriatal projections and via downstream, striato-entopeduncular, or striatonigral pathways. Taken together, our findings revealed a circuit regulating wakefulness through striatal D₁R neurons. Striatal D₁R neurons play an important role in controlling wakefulness by integrating the corticostriatal, thalamostriatal, and nigrostriatal projections and innervation of striato-entopeduncular or striatonigral pathways.

Physician Health Care Visits for Mental Health and Substance Use During the COVID-19 Pandemic in Ontario, Canada

IMPORTANCE

Physicians self-report high levels of symptoms of anxiety and depression, and surveys suggest these symptoms have been exacerbated by the COVID-19 pandemic. However, it is not known whether pandemic-related stressors have led to increases in health care visits related to mental health or substance use among physicians.

OBJECTIVE

To evaluate the association between the COVID-19 pandemic and changes in outpatient health care visits by physicians related to mental health and substance use and explore differences across physician subgroups of interest.

DESIGN, SETTING, AND PARTICIPANTS

A population-based cohort study was conducted using health administrative data collected from the universal health system (Ontario Health Insurance Plan) of Ontario, Canada, from March 1, 2017, to March 10, 2021. Participants included 34 055 physicians, residents, and fellows who registered with the College of Physicians and Surgeons of Ontario between 1990 and 2018 and were eligible for the Ontario Health Insurance Plan during the study period. Autoregressive integrated moving average models and generalized estimating equations were used in analyses.

EXPOSURES

The period during the COVID-19 pandemic (March 11, 2020, to March 10, 2021) compared with the period before the pandemic.

MAIN OUTCOMES AND MEASURES

The primary outcome was in-person, telemedicine, and virtual care outpatient visits to a psychiatrist or family medicine and general practice clinicians related to mental health and substance use.

RESULTS

In the 34 055 practicing physicians (mean [SD] age, 41.7 [10.0] years, 17 918 [52.6%] male), the annual crude number of visits per 1000 physicians increased by 27%, from 816.8 before the COVID-19 pandemic to 1037.5 during the pandemic (adjusted incident rate ratio per physician, 1.13; 95% CI, 1.07-1.19). The absolute proportion of physicians with 1 or more mental health and substance use visits within a year increased from 12.3% before to 13.4% during the pandemic (adjusted odds ratio, 1.08; 95% CI, 1.03-1.14). The relative increase was significantly greater in physicians without a prior mental health and substance use history (adjusted incident rate ratio, 1.72; 95% CI, 1.60-1.85) than in physicians with a prior mental health and substance use history.

CONCLUSIONS AND RELEVANCE

In this study, the COVID-19 pandemic was associated with a substantial increase in mental health and substance use visits among physicians. Physician mental health may have worsened during the pandemic, highlighting a potential greater requirement for access to mental health services and system level change.

[Emulation pulmonary nodules localization model:a novel non-invasive localization technique in resection of pulmonary nodules]

Objective: To explore the accuracy and efficiency of a novel 3D-printed emulation localization model of small pulmonary nodules in lung surgery. Methods: From April 2020 to April 2021, a total of 66 patients were selected in the study, who underwent localization and resection of pulmonary nodules with video-assisted thoracoscopic surgery (VATS) guided by the 3D-printed emulation localization model at Department of Thoracic Surgery, West China Hospital of Sichuan University. There were 13 males and 53 females, aged from 25 to 79 (52.7±11.4) years. Of all patients, 24 (36.4%) had single pulmonary nodule, and 42 (63.6%) had synchronous multiple pulmonary nodules. The chest high-resolution CT image data were utilized for digital reconstruction and 3D printing to make a tailored life-size emulation pulmonary nodules localization model, which was used to navigate real-time intraoperative localization of nodules. Clinical data including operative parameters, localization information, resection types and pathological findings of nodules were analyzed. The pulmonary nodules that doctors planned to resect were categorized into two categories:major nodules and additional nodules, according to their presence of invasion and radiological risk factors. The accuracy of localization and resection efficiency of nodules were evaluated in accordance with the categories of the nodules respectively. Results: On the basis of preoperative evaluation, there were 71 major nodules with median maximal diameter of 0.9 (0.6-1.3) cm, and 77 additional nodules with median maximal diameter of 0.5 (0.4-0.7) cm. All patients underwent VATS surgery, 52 of them (78.8%) were treated with uniportal VATS and 14 (21.2%) with triportal VATS. Among the patients with single nodule, 18 segmentectomies and 6 wedge resections were performed; whereas among the patients with multiple nodules, 5 segmentectomies, 14 wedge resections, and 23 combined pulmonary resections (including 2 cases of lobectomy+segmentectomy, 7 cases of lobectomy+wedge resections, and 14 cases of segmentectomy+wedge resections) were achieved. The median operative time was 93 (45-240) min, and the median resection time for all nodules was 51.4 (6.7-147.0) min. All major nodules were successfully resected and visibly dissected after removal, and all additional nodules were successfully resected with 85.7%(66/77) nodules visibly dissected. The accuracy rate of localization of both types of nodules was 100%. All major nodules were malignant, and the malignancy rate of additional nodules was 21.2%(14/66). Conclusion: This novel 3D-printed emulation localization model of small pulmonary nodules proved to be a non-invasive, accurate and efficient technique. Not only that, it has a unique advantage in localization of synchronous multiple pulmonary nodules.

Alloying dichalcogenolate-protected Ag21 eight-electron nanoclusters: a DFT investigation

The isoelectronic doping of dichalcogenolato nanoclusters of the type [Ag₂₁{E₂P(OR)₂}₁₂]⁺ (E = S, Se) by any heteroatom belonging to groups 9-12 was systematically investigated using DFT calculations. Although they can differ in their global structure, all of these species have the same M@M₁₂-centered icosahedral core. In any case, the different structure types are all very close in energy. In all of them, three different alloying sites can be identified (central, icosahedral, peripheral) and calculations allowed the trends in heteroatom site occupation preference across the group 9-12 family to be revealed. These trends are supported by complementary experimental results. They were rationalized on the basis of electronegativity, potential involvement in the bonding of valence d-orbitals and atom size. TD-DFT calculations showed that the effect of doping on optical properties is sizable and this should stimulate research on the modulation of luminescence properties in the dithiolato and diseleno families of complexes.

Reactivities of Interstitial Hydrides in a Cu11 Template: En Route to Bimetallic Clusters

In sharp contrast to surface hydrides, reactivities of interstitial hydrides are difficult to explore. When treated with a metal ion (Cu⁺ , Ag⁺ , and Au⁺ ), the stable Cu^I dihydride template [Cu₁₁ H₂ {S₂ P(Oⁱ Pr)₂ }₆ (C≡CPh)₃ ] (H₂ Cu₁₁ ) generates surprisingly three very different compounds, namely [CuH₂ Cu₁₁ {S₂ P(Oⁱ Pr)₂ }₆ (C≡CPh)₃ ]⁺ (1), [AgH₂ Cu₁₄ {S₂ P(Oⁱ Pr)₂ }₆ ((C≡CPh)₆ ]⁺ (2), and [AuCu₁₁ {S₂ P(Oⁱ Pr)₂ }₆ (C≡CPh)₃ Cl] (3). Compounds 1 and 2 are both M^I species and maintain the same number of hydride ligands as their H₂ Cu₁₁ precursor. Neutron diffraction revealed the first time a trigonal-pyramidal hydride coordination mode in the AgCu₃ environment of 2. 3 has no hydride and exhibits a mixed-valent [AuCu₁₁ ]¹⁰⁺ metal core, making it a two-electron superatom.

Serum uric acid is associated with incident metabolic syndrome independent of body shape index and body roundness index in healthy individuals

BACKGROUND AND AIMS

Elevated serum uric acid (SUA) levels, body shape index (BSI) and body roundness index (BRI) were associated with incident metabolic syndrome (MetS). We aimed to investigate the relationship among the SUA level, BSI, and BRI on the incidence of MetS.

METHODS AND RESULTS

We retrospectively included 6221 healthy individuals from annual health exams at our hospital between 2016/1/1 and 2016/12/31. We defined hyperuricemia as SUA levels greater than 7 mg/dl in men and 6 mg/dl in women and MetS according to the contemporary definition. The study cohort included 6221 healthy individuals with an overall incidence rate of MetS of 9.8%. Compared with the normouricemic group, the hyperuricemic group had a greater incidence of MetS (17.2% vs. 9.6%, P < 0.001). After full adjustment for confounders, the SUA level was significantly associated with incident MetS in addition to body mass index (BMI) (adjusted OR [aOR]: 1.161, 95% CI: 1.071-1.259, P < 0.001), BRI (aOR: 1.196, 95% CI: 1.104-1.296, P < 0.001), and BSI (aOR: 1.297, 95% CI: 1.200-1.403, P < 0.001). Regarding the anthropometric indices, BMI and BRI were independent predictors of incident MetS, but the BSI lost its significant association in multivariate logistic regression analyses. In sensitivity analyses, various thresholds of elevated SUA levels remained associated with incident MetS.

CONCLUSION

We showed a dose-response effect of SUA on incident MetS independent of BMI, BRI and BSI in healthy individuals. Future studies can use SUA levels to stratify cardiometabolic risk in healthy individuals.

CLINICAL TRIALS

ClinicalTrials.gov with the identification number NCT03473951.

Low-dose rivaroxaban associated with lower incidence of all-cause mortality and bleeding complications in older patients with non-valvular atrial fibrillation

Background

Low-dose rivaroxaban 10mg daily was used in the J-ROCKET AF trial, and it demonstrated the safety in Asian population. It remains unclear whether low-dose rivaroxaban vs. standard dose 20mg daily is associated with efficacy, safety, and net-clinical outcomes in older Asian patients with non-valvular atrial fibrillation.

Purpose

To evaluate the effects of low-dose rivaroxaban on efficacies and safeties in the old patients age more than 85 years.

Methods

We retrospectively enrolled the patients from medical records between Oct 2012 and Nov 2016. We used 2x2 factorial design by age of 85 years and use of low-dose rivaroxaban. The study outcomes were one-year all-cause mortality and bleeding complications.

Results

The study cohort consisted of 2,386 patients with the mean age 76.6 years (SD 10.5), 51.8% male, CHA2DS2Vsc 4.4 (SD 1.7) and HASBLED 1.6 (SD 1.0). In the age ≥85 group (n=593), low vs. standard dose rivaroxaban had a lower incidence of all-cause mortality (5.3% vs. 10.6%, P=0.021), whereas the incidence of all-cause mortality was greater in the low dose rivaroxaban compared with the standard dose in the age &lt;85 group (3.7% vs. 1.8%, P=0.012). No significant differences of bleeding complication rates were found between the low- and standard-dose rivaroxaban regarding age &lt;85 or ≥85 years. After adjusting for potential confounders, low dose rivaroxaban was associated with a decreased risk of all-cause mortality in the age ≥85 group (adjusted HR: 0.400 95% CI: 0.215–0.743, P=0.004), but the significant association was not found in the age &lt;85 group (adjusted HR: 1.101 95% CI: 0.557–2.174, P=0.782).

Conclusion

Low dose rivaroxaban was associated with a decreased risk of all-cause mortality in the patients with non-valvular atrial fibrillation and age ≥85 years.

Funding Acknowledgement

Type of funding sources: None.

Percutaneous transluminal angioplasty associated with a comparable risk of mortality in old patients with severe lower extremities arterial disease

Background

Percutaneous transluminal angioplasty (PTA) improves limb salvage rates in patients with severe lower extremity arterial disease (LEAD). It remains unknown whether PTA can be safely performed to the older LEAD patients.

Purpose

We investigated the effect of age ≥85 vs &lt;85 years on prognoses in LEAD patients.

Methods

We analyzed 222 LEAD patients from our previous retrospective cohort study between 2013 and 2018. All patients received percutaneous transluminal angioplasty. Study outcomes were in-hospital mortality and 1-year all-cause mortality and major adverse limb events (MALEs).

Results

The study included 222 patients aged 74±11 years (54% male), and 12.6% had acute limb ischemia. The older group had significantly higher rates of in-hospital (17.8 vs. 5.1%, P=0.009) and all-cause mortality (37.8% vs. 19.2%, P=0.016), but MALEs were not different significantly (8.9% vs. 16.9%, P=0.247). In multivariate logistic regression analyses, age ≥85 years was not associated with the increased risks of the study outcomes after we adjusted for potential confounders. The risk factors associated with 1-year all-cause mortality was the presence of acute limb ischemia (adjusted HR: 2.978, 95% CI: 1.502–5.905, P=0.002) and Rutherfold stages (adjusted HR: 2.135, 95% CI: 1.248–3.652, P=0.005).

Conclusion

Compared with the patients aged less than 85 years, the LEAD patients aged more than 85 years had favorable risks of mortality after receiving PTA, and the incident MALEs were not significantly different.

Funding Acknowledgement

Type of funding sources: None. Study outcomes in LEAD patients

[Treatment strategies and research progress of acute ilio-femoral deep vein thrombosis]

In the past,treatment of acute ilio-femoral deep vein thrombosis (IFDVT) was mainly based on anticoagulation alone,but 30%-50% of patients will develop post-thrombotic syndrome,causing a serious medical burden.Thrombus removal technology such as catheter-directed thrombolysis and percutaneous mechanical thrombectomy can effectively remove blood clots and compensate for the deficiencies of simple anticoagulation,which is expected to improve the prognosis of such disease,but the current evidence is insufficient,and other treatments such as filter implantation and compression therapy are also controversial.This article summarizes the treatment strategies and the latest progress of acute IFDVT,hoping to help the treatment of this type of disease.

Serum Uric Acid: A Murderer or Bystander for Cardiac-related Mortality?

In this issue of The Journal of Rheumatology, Colantonio, et al ¹ conducted a case-cohort study from the REGARDS study to evaluate whether the association between serum uric acid (SUA) and sudden cardiac death, and between SUA and incident coronary heart disease (CHD) events, is confounded by SLC2A9 single-nucleotide polymorphisms (SNPs). Incident CHD events were the composites of nonfatal myocardial infarction (MI) or CHD deaths.

All-selenolate-protected eight-electron platinum/silver nanoclusters

The first atomically and structurally precise platinum/silver superatoms protected by Se-donor ligands were synthesized in high yield by adopting ligand replacements on [PtAg₂₀{S₂P(OⁿPr)₂}₁₂] (3) with 12 equiv. of di-alkyl diselenophosph(in)ates. Structures of [PtAg₂₀{Se₂P(OR)₂}₁₂] (R = ⁿPr (1a), ⁱPr (1b)) and [PtAg₂₀{Se₂P(CH₂CH₂Ph)₂}₁₂] (2) were accurately determined by single-crystal X-ray diffraction to reveal an eight-electron [Pt@Ag₁₂]⁴⁺ icosahedral core embedded within a cube of eight silver(i) atoms and wrapped into a shell of 12 diselenophosph(in)ates. While the lowest energy absorption band of the Se derivatives is red-shifted to longer wavelengths in comparison with the S analogue, it is blue-shifted in the emission spectra. Density functional theory (DFT) and TD-DFT calculations rationalize the electronic structures as those of eight-electron superatoms, with their HOMO and LUMO being the 1P and 1D levels, respectively. The two UV-visible lowest bands are associated with 1P → 1D metal to metal charge transfer (MMCT) transitions. The blue shift observed for the S analogue results from a larger HOMO-LUMO gap in the case of dithiolate ligands.

Doping effect on the structure and properties of eight-electron silver nanoclusters

The bimetallic M₂₀ and M₂₁ compounds, {[Cu₃Ag₁₇{S₂P(OⁱPr)₂}₁₂]_0.5 [Cu₄Ag₁₆{S₂P(OⁱPr)₂}₁₂]_0.5} ({[1a]_0.5[1b]_0.5}) and [Cu₄Ag₁₇{S₂P(OⁱPr)₂}₁₂](PF₆) (2), have been structurally characterized, in which the Cu(I) ions are randomly distributed on the eight outer positions capping the eight-electron [Ag₁₃]⁵⁺ core. DFT calculations show that the statistical disorder results from the nearly neutral preference of copper to occupy any of the eight outer positions. Surprisingly, the UV-Vis absorption spectra of the M₂₀ and M₂₁ bimetallic nanoclusters display an almost identical absorption profile as that of their homometallic [Ag₂₀{S₂P(OⁱPr)₂}₁₂] and [Ag₂₁{S₂P(OⁱPr)₂}₁₂]⁺ relatives. This is rationalized by TD-DFT calculations, which show that the frontier orbitals of such eight-electron alloys are largely independent from the nature of the capping metal ions. A blue-shifted absorption is observed upon replacing by Au the central Ag atom in 2, forming the trimetallic compound [Cu₄AuAg₁₆{S₂P(OⁱPr)₂}₁₂](PF₆) (3).

Synthesis and Luminescence Properties of Two-Electron Bimetallic Cu-Ag and Cu-Au Nanoclusters via Copper Hydride Precursors

The synthesis, structural characteristics, and photophysical properties of luminescent Cu-rich bimetallic superatomic clusters [Au@Cu₁₂(S₂CNⁿPr₂)₆(C≡CPh)₄]⁺ (1a⁺), [Au@Cu₁₂{S₂P(OR)₂}₆(C≡CPh)₄]⁺ (2⁺), (2a⁺ = ⁱPr; 2b⁺ = ⁿPr), [Au@Cu₁₂{S₂P(C₂H₄Ph)₂}₆(C≡CPh)₄]⁺ (2c⁺), and [Ag@Cu₁₂{S₂P(OⁿPr)₂}₆(C≡CPh)₄]⁺ (3⁺) were studied. Compositionally uniform clusters 1⁺-3⁺ were isolated from the reaction of dithiolato-stabilized, polyhydrido copper clusters with phenylacetylene in the presence of heterometal salts. By using X-ray diffraction, the structures of 1a⁺, 2a⁺, 2b⁺, and 3⁺ were able to be determined. ESI-mass spectrometry and elemental analysis confirmed their compositions and purity. The structural characteristics of these clusters are similar with respect to displaying gold (or silver)-centered Cu₁₂ cuboctahedra surrounded by six dithiocarbamate/dithiophosph(in)ate and four alkynyl ligands. The doping of Au and Ag atoms into the polyhydrido copper nanoclusters significantly enhances their PL quantum yields from Ag@Cu₁₂ (0.58%) to Au@Cu₁₂ (55%) at ambient temperature in solution. In addition, the electrochemical properties of the new alloys were investigated by cyclic voltammetry.

High Hole Concentration and Diffusion Suppression of Heavily Mg-Doped p-GaN for Application in Enhanced-Mode GaN HEMT

The effect of Mg doping on the electrical and optical properties of the p-GaN/AlGaN structures on a Si substrate grown by metal organic chemical vapor deposition was investigated. The Hall measurement showed that the activation efficiency of the sample with a 450 sccm Cp₂Mg flow rate reached a maximum value of 2.22%. No reversion of the hole concentration was observed due to the existence of stress in the designed sample structures. This is attributed to the higher Mg-to-Ga incorporation rate resulting from the restriction of self-compensation under compressive strain. In addition, by using an AlN interlayer (IL) at the interface of p-GaN/AlGaN, the activation rate can be further improved after the doping concentration reaches saturation, and the diffusion of Mg atoms can also be effectively suppressed. A high hole concentration of about 1.3 × 10¹⁸ cm⁻³ can be achieved in the p-GaN/AlN-IL/AlGaN structure.

Isolation and Structural Elucidation of 15-Nuclear Copper Dihydride Clusters: An Intermediate in the Formation of a Two-Electron Copper Superatom

Highly reactive copper-dihydride clusters, [Cu₁₅ (H)₂ (S₂ CNR₂ )₆ (C₂ Ph)₆ ](PF₆ ) {R = ⁿ Bu (1_H ), ⁿ Pr (2_H ), ⁱ Bu (3_H )}, are isolated during the reaction of [Cu₂₈ H₁₅ {S₂ CNⁿ Bu₂ }₁₂ ](PF₆ ) with ten equivalents of phenylacetylene. They are found to be intermediates in the formation of the earlier reported two-electron superatom [Cu₁₃ (S₂ CNR₂ )₆ (C₂ Ph)₄ ]⁺ . Better yields are obtained by reacting dithiocarbamate sodium salts, [Cu(CH₃ CN)₄ ](PF₆ ), BH₄^- and phenylacetylene. The presence of two hydrides in the isolated clusters is confirmed by the synthesis and characterization of its deuteride analogue [Cu₁₅ (D)₂ (S₂ CNR₂ )₆ (C₂ Ph)₆ ]⁺ , and a single-crystal neutron structure of 2_H . Structural characterization of 1_H reveals a new bicapped icosahedral copper(I) cage encapsulating a linear copper dihydride (CuH₂ )^- unit. Reaction of 3_H with Au(I) salts yields a highly luminescent [AuCu₁₂ (S₂ CNⁱ Bu₂ )₆ (C₂ Ph)₄ ]⁺ cluster.

[Cu{SC(O)OiPr}]96: A Giant Self-Assembled Copper(I) Supramolecular Wheel Exhibiting Photoluminescence Tuning and Correlations with Dynamic Solvation and Solventless Synthesis

The hierarchical self-organization of structurally complex high-nuclearity metal clusters with metallosupramolecular wheel architectures that are obtained from the self-assembly of smaller solvated cluster units is rare and unique. Here, we use the potentially heteroditopic monothiocarbonate ligand and demonstrate for the first time the synthesis and structure of a solvated non-cyclic hexadecanuclear cluster [Cu{SC(O)OⁱPr}]₁₆·2THF (1) that can simultaneously desolvate and self-assemble in solution and subsequently form a giant metallaring, [Cu{SC(O)OⁱPr}]₉₆ (2). We also demonstrate a luminescent precursor to cluster (2) can be achieved through a solventless and rapid mechanochemical synthesis. Cluster (2) is the highest nuclearity copper(I) wheel and the largest metal cluster containing a heterodichalcogen (O, S) ligand reported to date. Cluster (2) also exhibits solid-state luminescence with relatively long emission lifetimes at 4.1, 13.9 (μs). The synthetic strategy described here opens new research avenues by replacing solvent molecules in stable {Cu₁₆} clusters with designed building units that can form new hybrid and multifunctional finite supramolecular materials. This finding may lead to the development of novel high-nuclearity materials self-assembled in a facile manner with tunable optical properties.