Approach to the "Missing" Diarylsilylene: Formation, Characterization, and Intramolecular C-H Bond Activation of Blue Diarylsilylenes with Bulky Rind Groups.

The treatment of the bulky Rind-based dibromosilanes, (Rind)2SiBr2 (2) [Rind = 1,1,7,7-tetra-R1-3,3,5,5-tetra-R2-s-hydrindacen-4-yl: EMind (a: R1 = Et, R2 = Me) and Eind (b: R1 = R2 = Et)], with two equivalents of tBuLi in Et2O at low temperatures resulted in the formation of blue solutions derived from the diarylsilylenes, (Rind)2Si: (3). Upon warming the solutions above -20 °C, the blue color gradually faded, accompanying the decomposition of 3 and yielding cyclic hydrosilanes (4) via intramolecular C-H bond insertion at the Si(II) center. The molecular structures of the bulky Eind-based 3b and 4b were confirmed by X-ray crystallography. Thus, at -20 °C, blue crystals were formed (Crystal-A), which were identified as mixed crystals of 3b and 4b. Additionally, colorless crystals of 4b as a singular component were isolated (Crystal-B), whose structure was also determined by an X-ray diffraction analysis. Although the isolation of 3 was difficult due to their thermally labile nature, their structural characteristics and electronic properties were discussed based on the experimental findings complemented by computational results. We also examined the hydrolysis of 3b to afford the silanol, (Eind)2SiH(OH) (5b).

Selective monooxygenation of diphosphenes with molecular oxygen.

The O2 splitting mediated by the bulky Rind-based diphosphenes resulted in the clean formation of the mixed-valent diphosphorus compounds, diphosphene oxides, with P2O moieties. Their structural features and electronic properties have been clearly characterized by experimental and theoretical methods.

Validation of the patient State Index for monitoring sedation state in critically ill patients: a prospective observational study.

PURPOSE: The Patient State Index (PSI) is a newly introduced electroencephalogram-based tool for objective and continuous monitoring of sedation levels of patients under general anesthesia. This study investigated the potential correlation between the PSI and the Richmond Agitation‒Sedation Scale (RASS) score in intensive care unit (ICU) patients and established the utility of the PSI in assessing sedation levels. METHODS: In this prospective observational study, PSI values were continuously monitored via SedLine® (Masimo, Irvine, CA, USA); the RASS score was recorded every 2 h for patients on mechanical ventilation. Physicians and nurses were blinded to the PSI values. Overall, 382 PSI and RASS score sets were recorded for 50 patients. RESULTS: The PSI score correlated positively with RASS scores, and Spearman's rank correlation coefficient between the PSI and RASS was 0.79 (95% confidence interval [CI]: 0.75‒0.83). The PSI showed statistically significant difference among the RASS scores (Kruskal‒Wallis chi-square test: 242, df = 6, P < 2.2-e16). The PSI threshold for distinguishing light (RASS score ≥ - 2) sedation from deep sedation (RASS score ≤ - 3) was 54 (95% CI: 50-65; area under the curve, 0.92 [95% CI: 0.89‒0.95]; sensitivity, 0.91 [95% CI: 0.86‒0.95]; specificity, 0.81 [95% CI: 0.77-0.86]). CONCLUSIONS: The PSI correlated positively with RASS scores, which represented a widely used tool for assessing sedation levels, and the values were significantly different among RASS scores. Additionally, the PSI had a high sensitivity and specificity for distinguishing light from deep sedation. The PSI could be useful for assessing sedation levels in ICU patients. University Hospital Medical Information Network (UMIN000035199, December 10, 2018).

A series of (E)-1,2-diaryldigermenes incorporating bulky Eind groups: structural characteristics and absorption properties.

A series of (E)-1,2-diaryldigermenes, (Eind)ArGeGeAr(Eind) [Ar = phenyl (2), thiophen-2-yl (3), 9,9-dimethyl-2-fluorenyl (4) and 2,2'-bithiophen-5-yl (5)], supported by the fused-ring bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups, have been obtained as yellow-orange to red crystalline solids by the reaction of 1,2-dibromodigermene, (Eind)BrGeGeBr(Eind) (1), with ArLi. In the crystals of 2-5, the digermene cores show a flexible nature adopting a trans-bent geometry with the trans-bent angles (θ) between the Ge-Ge vector and the CEind-Ge-CAr plane of 34.04(12)° (2), 38.3(3)° and 38.8(3)° (3), 33.69(12)° (4) and 39.30(13)° (5). In the UV-vis spectra, strong π-π* absorptions have been observed with an absorption maximum at 451 nm (ε = 1.3 × 104) (2), 455 nm (ε = 9.7 × 103) (3), 480 nm (ε = 1.3 × 104) (4) and 497 nm (ε = 1.4 × 104) (5), retaining the GeGe double bond in solution. The absorption data and DFT calculations provide evidence for the intrinsic π-conjugation between the GeGe chromophore and aromatic rings involving the narrowing of the HOMO-LUMO gaps (ΔE) with the extension of the carbon π-electron systems.

Heavier element-containing aromatics of [4n+2]-electron systems.

While the implication of the aromaticity concept has been dramatically expanded to date since its emergence in 1865, the classical [4n+2]/4n-electron counting protocol still plays an essential role in evaluating the aromatic nature of compounds. Over the last few decades, a variety of heavier heterocycles featuring the formal [4n+2] π-electron arrangements have been developed, which allows for assessing their aromatic nature. In this review, we present recent developments of the [4n+2]-electron systems of heavier heterocycles involving group 13-15 elements. The synthesis, spectroscopic data, structural parameters, computational data, and reactivity are introduced.

A Crystalline B4N2 Dewar Benzene as a Building Block for Conjugated B,N-Chains.

Dewar benzene, one of the isolable valence isomers of C6H6, has been extensively studied since its first synthesis in 1962. By contrast, the chemistry of inorganic congeners of Dewar benzene, which can be formally gained by replacing the skeletal carbon atoms with heteroatoms, has been less developed despite their peculiar structural and electronic features. Among them, the extant B,N-Dewar benzenes are limited to the B3N3 system. Herein, we report the development of the first example of an isolable B4N2 Dewar benzene, 3. As predicted by DFT calculations, a judicious selection of the substituents allows synthesizing 3. Single-crystal X-ray analysis, NMR, and computational studies confirmed that 3 possesses a high-lying B(sp3)-B(sp3) σ-bond at the bridgehead position. Reactions with ethylene and phenylacetylene proceeded smoothly under mild conditions, affording the fused B4C4N2 ring systems (4 and 5). Structural characterization as well as DFT calculations revealed that compounds 4 and 5 involve a rigid and conjugated (BN)4 tetraene scaffold. Formation of 4 and 5 demonstrates that 3 may serve as a building block for the construction of conjugated B,N-chains.

A Neutral and Aromatic Boron-Rich Inorganic Benzene.

A neutral 1,4-diaza-2,3,5,6-tetraborinine derivative (3) featuring a 6π ring system has been synthesized and structurally characterized. The prospective aromatic nature of 3 was assessed by single-crystal X-ray analysis, NMR, and UV/Vis absorption spectroscopy as well as computational studies. Furthermore, preliminary reactivity investigations showed that 3 does not only react with diphenyl acetylene but also readily captures CO2 in a [4+2] cycloaddition under ambient conditions.

Aromatic nature of neutral and dianionic 1,4-diaza-2,3,5,6-tetraborinine derivatives.

The aromatically relevant parameters of boron-rich inorganic benzenes-neutral and dianionic 1,4-diaza-2,3,5,6-tetraborinine derivatives (B4N2R6)-have been computationally estimated and evaluated from geometric, electronic, magnetic, and energetic points of view. The majority of the criteria (ASE, NICSzz, ELF, and PDI) indicate that the aromaticity of the neutral B4N2 benzene analogue stabilized by Lewis bases lies in between those of benzene and borazine. On the other hand, the aromaticity of the dianionic B4N2 benzene analogue 4' is controversial. The pronounced aromatic nature of 4' is supported by ELFπ, PDI, and NICSπzz, but ASE, the FiPC-NICS plot, and ACID oppose this. These data confirm that even with the same B4N2-skeletal framework of a 6π-system, the aromatic feature varies depending on the overall charge of the B4N2 systems.

Inorganic Benzene Valence Isomers.

It has been computationally proposed that there are more than 200 possible isomeric structures for the C6H6 molecule, among which benzene (CH)6 represents the most thermodynamically stable molecule and its chemistry has been extensively developed. Three benzene valence isomers (CR)6, namely, prismane, Dewar benzene, and benzvalene, have also been synthesized to date. Incorporation of heteroatoms in the skeletal frameworks allows access to inorganic analogues of benzene and its valence isomers, which have attracted considerable attention due to their peculiar structural and electronic features. Experimentally, more than 30 examples of inorganic benzene and its valence isomers have been developed and characterized so far. In this contribution, their synthesis and characterization, as well as their stability and chemical properties, are discussed.

Germylone-bridged bimetallic Ir and Rh complexes.

The reactions of germylone 1 with one equivalent of [M(COD)Cl]2 (M = Ir, Rh) afforded the germylone-bridged bimetallic complexes 2 and 3, which have been spectroscopically and structurally characterized. Density functional theory (DFT) studies reveal the relatively strong interactions between the Ge atom and these metals. By the reaction of [Rh(COD)Cl]2 with CO followed by addition of 1, a complex 4 involving a Rh-Ge-Rh-Ge-Rh chain was also synthesized.

Zwitterionic Inorganic Benzene Valence Isomer with σ-Bonding between Two π-Orbitals.

Despite the large number of plausible isomers of benzene (C6H6), only four valence isomers [(CH)6] have been experimentally detected, all of which are nonionic and possess skeletal frameworks built from localized C-C bonds. Herein, we present the isolation of a diazatetraborabenzene analogue of a hypothetical zwitterionic valence isomer of benzene. Therein, two electrons are delocalized over the four boron atoms in the six-membered B4N2 ring, which is a result of the σ-bonding interaction between two odd-electron B-B π-orbitals. Simple treatment with a crown ether leads to the formation of a paramagnetic potassium-doped radical ion pair that exhibits a thermally populated triplet character.

Bis(stibahousene).

Strained hydrocarbons constitute one of the most prominent classes of organic compounds. Among them, bicyclo[2.1.0]pentene ("housene") derivatives represent a highly challenging and very attractive class. Although organic housenes have been known for more than five decades, there are still very few of them containing heavier main group elements. In this paper, we report on the two housene-type structures, novel monomeric stibahousene and dimeric bis(stibahousene). The bonding natures of both compounds were approached from both experimental and computational directions to reveal their peculiar structural features.

A possible origin population of pathogenic intestinal nematodes, Strongyloides stercoralis, unveiled by molecular phylogeny.

Humans and dogs are the two major hosts of Strongyloides stercoralis, an intestinal parasitic nematode. To better understand the phylogenetic relationships among S. stercoralis isolates infecting humans and dogs and to assess the zoonotic potential of this parasite, we analyzed mitochondrial Cox1, nuclear 18S rDNA, 28S rDNA, and a major sperm protein domain-containing protein genes. Overall, our analyses indicated the presence of two distinct lineages of S. stercoralis (referred to as type A and type B). While type A parasites were isolated both from humans and dogs in different countries, type B parasites were found exclusively in dogs, indicating that the type B has not adapted to infect humans. These epidemiological data, together with the close phylogenetic relationship of S. stercoralis with S. procyonis, a Strongyloides parasite of raccoons, possibly indicates that S. stercoralis originally evolved as a canid parasite, and later spread into humans. The inability to infect humans might be an ancestral character of this species and the type B might be surmised to be an origin population from which human-infecting strains are derived.

Potential impact of surgical periodontal therapy on oral health-related quality of life in patients with periodontitis: a pilot study.

AIM: To gain insight into the impact of periodontal surgery on oral health-related quality of life (QoL) of patients with periodontitis. MATERIAL AND METHODS: Study participants were recruited from moderate to severe periodontitis patients. After initial periodontal therapy, participants received periodontal surgery. Oral Health-related Quality of Life Model for Dental Hygiene (OHRQL) was used to assess participant's QoL at each time point of periodontal evaluation (baseline, at least 3 weeks after initial therapy and 3-4 months after surgery). RESULTS: A total of 21 patients completed OHRQL assessment after surgery. Compared with baseline, a progressive improvement in periodontal parameters was observed during the periodontal therapy. The total mean OHRQL score at baseline (25.5 ± 11.4) was significantly reduced (improved) after initial therapy and after surgery (16.7 ± 9.5 and 15.0 ± 9.7, respectively; p < 0.01). However, no significant difference was found between the OHRQL score after initial therapy and that after surgery. CONCLUSIONS: No significant differences in patients' oral health-related QoL were observed between post-initial therapy and post-surgery intervals, although a tendency of surgery to determine an improvement in QoL was observed when compared with post-initial treatment.

Volume overload and pressure overload due to left-to-right shunt-induced myocardial injury. - Evaluation using a highly sensitive cardiac Troponin-I assay in children with congenital heart disease-.

BACKGROUND: Cardiac troponin I (cTnI) is currently considered to be the most sensitive and specific biochemical marker of acute coronary syndrome and acute myocardial infarction. However, few reports have described the use of cTnI assays for evaluating abnormal hemodynamic load in children with congenital heart disease (CHD). It was hypothesized that significant hemodynamic overload due to a left-to-right shunt induces myocardial injury. METHODS AND RESULTS: A highly sensitive cTnI assay was used to measure the serum cTnI levels in 30 children with atrial septal defect (ASD), 32 children with ventricular septal defect (VSD), and 350 healthy children. Cardiac catheterization was performed in the children with ASD and VSD to determine the ratio of pulmonary to systemic blood flow, the ratio of pulmonary to systemic arterial pressure (Pp/Ps), the pulmonary vascular resistance index, and the right and left ventricular end-diastolic volume. Serum cTnI levels in both the ASD and VSD children were significantly higher than those in healthy children (P<0.05 and P<0.01, respectively). Furthermore, serum cTnI levels significantly correlated with Pp/Ps (r=0.745, P<0.001) in VSD children. CONCLUSIONS: Significant volume and pressure overload due to a left-to-right shunt induce myocardial injury and might eventually cause irreversible myocardial remodeling in children with CHD. The serum cTnI level is a useful biomarker for evaluating myocardial damage associated with pulmonary hypertension in VSD children.

Two-year follow-up of treatment of intrabony periodontal defect with enamel matrix derivative.

The aim of this retrospective clinical study was to evaluate 2-year follow-up results following regenerative periodontal surgery for intrabony defects using enamel matrix derivative (EMD). Thirteen patients (mean age: 53 years) with a clinical diagnosis of chronic periodontitis were subjected to data analysis. A total of 25 sites with intrabony defects received regenerative therapy with EMD. Follow-up continued for a minimum of 2 years. Treatment of intrabony defects with EMD yielded a statistically significant improvement in the mean values of probing depth and gains in clinical attachment level (CAL) at 2 years compared with those at baseline (p<0.001). Sites treated with EMD demonstrated a mean CAL gain of 3.4 mm and 3.2 mm at 6 months and 2 years, respectively. No statistically significant difference in gain in CAL was found between the 6-month and 2-year results. A gain in CAL of ≥3 mm from at baseline was found in 17 sites at 2 years. This gain was achieved with minimal recession of gingival margin and was sustained over a given period of time. A trend toward a progressive increase in radiopacity, suggestive of bone-fill, was observed. In summary, treatment of intrabony defects with EMD resulted in clinically favorable outcomes. The clinical improvements obtained with regenerative therapy with EMD were maintained over a period of 2 years.

Surgical periodontal therapy at Tokyo Dental College Suidobashi Hospital: a statistical profile in 2010-2011.

The aim of the present study was to investigate the profile of surgical periodontal therapy performed at the Suidobashi Hospital of Tokyo Dental College, during the period of April 2010 through March 2011. A total of 112 periodontal surgeries in 69 patients (mean age: 51.4 years; 28 men and 41 women) were registered for the data analysis. The surgical interventions performed by 17 dentists comprised 79 cases of open flap debridement, 27 cases of periodontal regenerative therapy with enamel matrix derivative and 6 cases of periodontal plastic surgery. Eighty percent of the surgical sites were in the molar region and 41 cases had furcation involvement. In these patients, an improvement in oral hygiene status was observed prior to surgery: the mean plaque score of 45% at initial visit was significantly reduced to 31% after initial periodontal therapy (p<0.01). At sites that subsequently received open flap debridement or periodontal regenerative therapy, the mean probing depth and clinical attachment level after initial therapy was 6.4 mm and 7.6 mm, respectively. These values were significantly lower than those at initial visit (p<0.01). Lower prevalence of sites with positive bleeding on probing was observed after initial therapy. The initial periodontal therapy performed was considered to be effective in improving the periodontal condition of the sites prior to surgery. More effort, however, is indicated in improvement of patient oral hygiene status.

Treatment of periodontal defects with enamel matrix derivative: clinical evaluation at early healing stages.

The aim of this retrospective clinical study was to evaluate the treatment of intrabony periodontal defects with enamel matrix derivative (EMD) during the early stages of healing. Sixteen patients aged 38-77 years with a clinical diagnosis of chronic periodontitis were subjected to data analysis. A total of 25 teeth with various osseous defects received regenerative therapy with EMD, and were followed for a minimum of 6 months. Post-operative healing was uneventful in the majority of cases. Treatment of the intrabony defects with EMD led to a statistically significant improvement in the mean value of probing depth at 3 months compared with that at baseline (p<0.001). Mean values of attachment gain at 3 and 6 months were of clinical significance: 3.6+/-1.8mm and 3.2+/-1.5mm, respectively. Reduction in probing depth was achieved with minimal recession of gingival margin and was sustained over a time course of 6 months. A progressive increase in radiopacity, suggestive of initial signs of bone-fill, was observed by 6 months. In summary, the results suggest that treatment of intrabony defect with EMD induces favorable periodontal healing with a high level of predictability.

Advances in artificial lungs.

Artificial lungs have already been developed as complete artificial organs, and results of many investigations based on innovative concepts have been reported continuously. In open-heart surgery, artificial lungs are used for extracorporeal circulation to maintain gas exchange, and the commercial products currently available perform adequately, including providing for antithrombogenicity. However, patients after cardiopulmonary arrest or severe respiratory/circulatory failure have required long-term assist with extracorporeal membrane oxygenation (ECMO). The number of artificial lungs used for ECMO in those cases has shown significant growth in recent years. Therefore, it is expected that durability and antithrombogenicity will ensure the prolonged use of an artificial lung for several weeks or months. Furthermore, interests in research are shifting to use of oxygenators as a bridge to lung transplantation and an implantable artificial lung. This paper discusses recent advances in artificial lungs, focusing on the current state and on trends in research and development.