Green Alternatives to Zinc Dialkyldithiophosphates: Vanadium Oxide-Based Additives.

A functionalized vanadyl(IV) acetylacetonate (acac) complex has been found to be a superior and highly effective antiwear agent, affording remarkable wear protection, compared to the current industry standard, zinc dialkyldithiophosphates (ZDDPs). Analysis of vanadium speciation and the depth profile of the active tribofilms by a combination of X-ray absorption near-edge structure (XANES), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS) analyses indicated a mixed-valence oxide composite, comprising V(III), V(IV), and V(V) species. A marked difference in composition between the bulk and the surfaces of the tribofilms was found. The vanadyl(VI) acac precursor has the potential to reduce or even replace ZDDP, which would represent a paradigm shift in the antiwear agent design. A major benefit relative to ZDDPs is the absence of S and P moieties, eliminating the potential for forming noxious and environmentally harmful byproducts of these elements.

Exploration of Solid-State vs Solution-State Structure in Contact Ion Pair Systems: Synthesis, Characterization, and Solution-State Dynamics of Zinc Diphenyl Phosphate, [Zn{O2P(OPh)2}2], Donor-Base-Supported Complexes.

A family of zinc phosphate complexes supported by nitrogen donor-base ligands have been synthesized, and their molecular structures were identified in both the solid (X-ray crystallography) and solution state (DOSY NMR spectroscopy). [Zn{O2P(OPh)2}2]∞ (1), formed from the reaction of Zn[N(SiMe3)2]2 with HO(O)P(OPh)2 coordinates to donor-base ligands, i.e., pyridine (Py), 4-methylpyridine (4-MePy), 2,2-bipyridine (bipy), tetramethylethylenediamine (TMEDA), pentamethyldiethylenetriamine (PMDETA), and 1,3,5-trimethyl-1,3,5-triazacyclohexane (Me3-TAC), to produce polymeric 1D structures, [(Py)2Zn{O2P(OPh)2}2]∞ (2) and [(4-MePy)2Zn{O2P(OPh)2}2]∞ (3), the bimetalic systems, [(Bipy)Zn{O2P(OPh)2}2]2 (4), [(TMEDA)Zn{O2P(OPh)2}2]2 (5), and [(Me3-TAC)Zn{O2P(OPh)2}2]2 (7), as well as a mono-nuclear zinc bis-diphenylphosphate complex, [(PMDETA)Zn{O2P(OPh)2}2] (6). 1H NMR DOSY has been used to calculate averaged molecular weights of the species. Studies are consistent with the disassembly of polymeric 3 into the bimetallic species [(Me-Py)2·Zn2{O2P(OPh)2}4], where the Me-Py ligand is in rapid exchange with free Me-Py in solution. Further 1H DOSY NMR studies of 4 and 5 reveal that dissolution of the complex results in a monomer dimer equilibrium, i.e., [(Bipy)Zn{O2P(OPh)2}2]2 ⇆ 2[(Bipy)Zn{O2P(OPh)2}2] and [(TMEDA)Zn{O2P(OPh)2}2]2 ⇆ 2[(TMEDA)Zn{O2P(OPh)2}2], respectively, in which the equilibria lie toward formation of the monomer. As part of our studies, variable temperature 1H DOSY experiments (223 to 313 K) were performed upon 5 in d8-tol, which allowed us to approximate the enthalpy [ΔH = -43.2 kJ mol-1 (±3.79)], entropy [ΔS = 109 J mol-1 K-1 (±13.9)], and approximate Gibbs free energy [ΔG = 75.6 kJ mol-1 (±5.62) at 293 K)] of monomer-dimer equilibria. While complex 6 is shown to maintain its monomeric solid-state structure, 1H DOSY experiments of 7 at 298 K reveal two separate normalized diffusion coefficients consistent with the presence of the bimetallic species [(TAC)2-xZn2{O2P(OPh)2}4], (x = 1 or 0) and free TAC ligand.

Lithium, Tin(II), and Zinc Amino-Boryloxy Complexes: Synthesis and Characterization.

Analogous to the ubiquitous alkoxide ligand, metal boroxide and boryloxy complexes are an underexplored class of hard anionic O- ligand. A new series of amine-stabilized Li, Sn(II), and Zn boryloxy complexes, comprising electron-rich tetrahedral boron centers have been synthesized and characterized. All complexes have been characterized by one-dimensional (1D), two-dimensional (2D), and DOSY NMR, which are consistent with the solid-state structures unambiguously determined via single-crystal X-ray diffraction. Electron-rich µ2- (Sn and Zn) and µ3- (Li) boryloxy binding modes are observed. Compounds 6-9 are the first complexes of this class, with the chelating bis- and tris-phenol ligands providing a scaffold that can be easily functionalized and provides access to the boronic acid pro-ligand, hence allowing facile direct synthesis of the resulting compounds. Computational quantum chemical studies suggest a significant enhancement of the π-donor ability of the amine-stabilized boryloxy ligand because of electron donation from the amine functionality into the p-orbital of the boron atom.

Tin(II) Ureide Complexes: Synthesis, Structural Chemistry, and Evaluation as SnO Precursors.

In an attempt to tailor precursors for application in the deposition of phase pure SnO, we have evaluated a series of tin (1-6) ureide complexes. The complexes were successfully synthesized by employing N,N'-trialkyl-functionalized ureide ligands, in which features such as stability, volatility, and decomposition could be modified with variation of the substituents on the ureide ligand in an attempt to find the complex with the ideal electronic, steric, or coordinative properties, which determine the fate of the final products. The tin(II) ureide complexes 1-6 were synthesized by direct reaction [Sn{NMe2}2] with aryl and alkyl isocyanates in a 1:2 molar ratio. All the complexes were characterized by NMR spectroscopy as well as elemental analysis and, where applicable, thermogravimetric (TG) analysis. The single-crystal X-ray diffraction studies of 2, 3, 4, and 6 revealed that the complexes crystallize in the monoclinic space group P2(1)/n (2 and 4) or in the triclinic space group P-1 (3 and 6) as monomers. Reaction with phenyl isocyanate results in the formation of the bimetallic species 5, which crystallizes in the triclinic space group P-1, a consequence of incomplete insertion into the Sn-NMe2 bonds, versus mesityl isocyanate, which produces a monomeric double insertion product, 6, under the same conditions, indicating a difference in reactivity between phenyl isocyanate and mesityl isocyanate with respect to insertion into Sn-NMe2 bonds. The metal centers in these complexes are all four-coordinate, displaying either distorted trigonal bipyramidal or trigonal bipyramidal geometries. The steric influence of the imido-ligand substituent has a clear effect on the coordination mode of the ureide ligands, with complexes 2 and 6, which contain the cyclohexyl and mesityl ligands, displaying κ2-O,N coordination modes, whereas κ2-N,N' coordination modes are observed for the sterically bulkier tert-butyl and adamantyl derivatives, 3 and 4. The thermogravimetric analysis of the complexes 3 and 4 exhibited excellent physicochemical properties with clean single-step curves and low residual masses in their TG analyses suggesting their potential utility of these systems as MOCVD and ALD precursors.

Evaluation of Sn(II) aminoalkoxide precursors for atomic layer deposition of SnO thin films.

We have successfully prepared and structurally characterized a family of eight tin(II) heteroleptic complexes, [Sn(NR2)(ON)]x (NR2 = NMe2 (1a-d) or N(SiMe3)2 (2a-d); x = 1 or 2) and four homoleptic systems, [Sn(κ2-ON)2] (3a-d) from a series of aminoalcohols and fluorinated aminoalcohols (H{ON}) having a different number of methyl/trifluoromethyl substituents at the α-carbon atom, [HOC(R1)(R2)CH2NMe2] (R1 = R2 = H (H{dmae}) (a); R1 = H, R2 = Me (H{dmap}) (b); R1 = R2 = Me (H{dmamp}) (c); R1 = R2 = CF3 (H{Fdmamp}) (d)). The synthetic route used reactions of either [Sn{N(SiMe3)2}2] or [Sn(NMe2)2] with one or two equivalents of the aminoalcohols (a-d) in dry aprotic solvents leading to elimination of amines and formation of the Sn(II) species 1a-d, 2a-d and 3a-d respectively. All complexes were thoroughly characterized by NMR spectroscopy (1H, 13C, 19F, and 119Sn) as well as single-crystal X-ray diffraction studies. In all case the solid state molecular structures of the complexes have been unambiguously established: the solid state structures 1a-b and 1c are dimeric with central {Sn2N2} cores resulting from bridging {µ2-NMe2} units, in which the Sn(II) atoms are four-coordinate. In contrast, the solid state structures of complexes 1c and 2a-c possess similarly dimeric structures, with four-coordinate Sn(II) atoms, in which the oxygen atoms of the {ON} ligand bridge two Sn(II) centres to form dimers with a central {Sn2O2} core. Uniquely in this study, 2d, [Sn(κ2-O,N-OCMe2CH2NMe2){N(SiMe3)2}] is monomeric with a three coordinate Sn(II) centre. The homoleptic complexes 3a-d are all isostructural with monomeric four-coordinate structures with disphenoidal geometries. Solution state NMR studies reveal complicated ligand exchange processes in the case of the heteroleptic complexes 1a-d and 2a-d. Contrastingly, the homoleptic systems 3a-d show no such behaviour. While complexes 1a-d and 2a-d displayed either poor thermal stability or multistep thermal decomposition processes, the thermal behaviour of the homoleptic complexes, 3a-d, was investigated in order to determine the effects, if any, of the degree of fluorination and asymmetry of the aminoalkoxide ligands on the suitability of these complexes as ALD precursors for the deposition of SnO thin films.

Individuals With Scleroderma May Have Increased Risk of Sleep-Disordered Breathing.

STUDY OBJECTIVES: Scleroderma is associated with abnormal skin thickening, interstitial lung disease, pulmonary hypertension, and abnormalities of the upper airway. These changes can cause cardiopulmonary complications, potentially including sleep-disordered breathing. The objective of this study is to examine the risk of sleep-disordered breathing in patients with scleroderma. METHODS: We retrospectively identified patients with documented scleroderma. We abstracted data from their electronic health records, including findings from antibody tests, serial pulmonary function tests, transthoracic echocardiography, high-resolution computed tomography, and overnight forehead oximetry. RESULTS: We identified 171 patients with scleroderma. Mean age at the time of initial consult was 56.5 years (range, 18-96 years), and 150 (86.7%) were women. Scleroderma was categorized as limited disease for 108 (62.4%), diffuse disease for 59 (34.1%), and mixed connective tissue disease for 6 (3.5%). Fifty-four patients (31.2%) had abnormal overnight forehead oximetry results, defined as an oxygen desaturation index greater than 5 or a baseline mean arterial oxygen saturation level less than 90%. CONCLUSIONS: Cardiopulmonary complications are common in patients with scleroderma, one of which may be sleep-disordered breathing. In our cohort, approximately one-third of individuals with scleroderma had evidence of sleep-disordered breathing. Moreover, the rate of sleep-disordered breathing in our population of scleroderma patients was twice the rate of pulmonary hypertension and was approximately the same as the rate of interstitial lung disease. Future prospective studies are needed to further assess the role of sleep-disordered breathing in scleroderma clinical outcomes.

Examining the Utility of a Novel Neurologic Test in Patients With Obstructive Sleep Apnea: A Pilot Study.

Purpose: To test the association between participant King-Devick Test (KDT) times and obstructive sleep apnea (OSA) severity and evaluate for improvement after continuous positive airway pressure (CPAP) treatment. Methods: Study dates January 30 to July 31, 2018. Patients were referred for initial evaluation of sleep disordered breathing concerns. OSA severities were defined by Apnea Hypopnea Index (AHI) results, with ≥15 considered at least moderate OSA. The KDT is an objective physical measure of brain function. We estimated correlation between KDT time and AHI and compared mean KDT time between patients with and without moderate OSA. For the OSA subgroup, we evaluated for potential improvement in KDT after CPAP. Results: We enrolled 60 participants, of whom 35 (58.3%) had OSA with an AHI ≥15. Initial analyses noted no significant KDT time differences between patients based on OSA severity. However, after excluding 3 participants who had baseline neurologic illness, adjusted analyses demonstrated that mean KDT time was significantly prolonged for patients with moderate or greater OSA (AHI ≥15) as compared to those with mild or no sleep apnea (AHI <15); 63.4 seconds (95% CI 58.9-67.8) versus 55.7 seconds (95% CI 50.2-61.1), P = .03. CPAP-treated subjects demonstrated significantly improved KDT test times; 63.5 seconds mean pretreatment versus 55.6 posttreatment; -6.6 seconds mean difference, 95%CI (-12.0, -1.13), P = .02. Conclusion: Neurologic abnormalities in patients with OSA are potentially demonstrable utilizing this objective physical measure. Significant improvement is achieved in patients after CPAP treatment.

Synthetic, Structural, and Computational Studies on Heavier Tetragen and Chalcogen Triazenide Complexes.

The syntheses of the triazenide complexes [{N(NDipp)2}2M] (Dipp = 2,6-di-isopropylphenyl; M = Ge(II) (1), Sn(II) (2), Pb(II) (3), and Te(II) (5)) are described for the first time. These compounds have been characterized by single-crystal X-ray diffraction and heteronuclear NMR spectroscopy. Density functional theory calculations were employed to confirm the presence and nature of the stereochemically active lone pairs in 1-5, alongside the Gibbs energy changes for their general synthesis, which enable the rationalization of observed reactivities.

Aerosol-Assisted Chemical Vapor Deposition of ZnS from Thioureide Single Source Precursors.

A family of 12 zinc(II) thoureide complexes, of the general form [{L}ZnMe], [{L}Zn{N(SiMe3)2}], and [{L}2Zn], have been synthesized by direct reaction of the thiourea pro-ligands iPrN(H)CS(NMe2) H[L1], CyN(H)CS(NMe2) H[L3], tBuN(H)CS(NMe2) H[L2], and MesN(H)CS(NMe2) H[L4] with either ZnMe2 (1:1) or Zn{N(SiMe3)2}2 (1:1 and 2:1) and characterized by elemental analysis, NMR spectroscopy, and thermogravimetric analysis (TGA). The molecular structures of complexes [{L1}ZnMe]2 (1), [{L2}ZnMe]2] (2), [{L3}ZnMe]∞ (3), [{L4}ZnMe]2] (4), [{L1}Zn{N(SiMe3)2}]2 (5), [{L2}Zn{N(SiMe3)2}]2 (6), [{L3}Zn{N(SiMe3)2}]2] (7), [{L4}Zn{N(SiMe3)2}]2] (8), [{L1}2Zn]2 (9), and [{L4}2Zn]2 (12) have been unambiguously determined using single crystal X-ray diffraction studies. Thermogravimetric analysis has been used to assess the viability of complexes 1-12 as single source precursors for the formation of ZnS. On the basis of TGA data compound 9 was investigated for its utility as a single source precursor to deposit ZnS films on silica-coated glass and crystalline silicon substrates at 150, 200, 250, and 300 °C using an aerosol assisted chemical vapor deposition (AACVD) method. The resultant films were confirmed to be hexagonal-ZnS by Raman spectroscopy and PXRD, and the surface morphologies were examined by SEM and AFM analysis. Thin films deposited from (9) at 250 and 300 °C were found to be comprised of more densely packed and more highly crystalline ZnS than films deposited at lower temperatures. The electronic properties of the ZnS thin films were deduced by UV-Vis spectroscopy to be very similar and displayed absorption behavior and band gap (Eg = 3.711-3.772 eV) values between those expected for bulk cubic-ZnS (Eg = 3.54 eV) and hexagonal-ZnS (Eg = 3.91 eV).

Subpectoral implantation of the hypoglossal nerve stimulator: An effective technical modification.

Upper airway stimulation is now a well-established treatment option for selected patients with obstructive sleep apnea. The implanted pulse generator of this system activates the hypoglossal nerve and is routinely placed in a subcutaneous pocket overlying the pectoralis muscle. This case report describes a patient with a history of bilateral mastectomy and radiation for breast cancer who required explantation due to device exposure and infection. The patient was successfully reimplanted by placing the implantable pulse generator deep to the pectoralis major muscle. Clinical circumstances involving the chest wall may warrant subpectoral placement of the implanted pulse generator. Laryngoscope, 129:2420-2423, 2019.

Obstructive sleep apnea: A better Dx model for primary care.

This study identified a method that provides a truer assessment of disease probability than has been achieved with history and physical exam evaluation.

Synthesis, characterisation and thermal properties of Sn(ii) pyrrolide complexes.

SnO is a rare example of a stable p-type semiconductor material. Here, we describe the synthesis and characterisation of a family of Sn(ii) pyrrolide complexes for future application in the MOCVD and ALD of tin containing thin films. Reaction of the Sn(ii) amide complex, [{(Me3Si)2N}2Sn], with the N,N-bidentate pyrrole pro-ligand, L1H, forms the hetero- and homoleptic complexes [{L1}Sn{N(SiMe3)2}] (1) and [{L1}2Sn] (2), respectively, bearing the 2-dimethylaminomethyl-pyrrolide ligand (L1). Reaction of [{(Me3Si)2N)}2Sn] with the pyrrole-aldimine pro-ligands, L2H-L7H, results in the exclusive formation of the homoleptic bis-pyrrolide complexes [{L2-7}2Sn] (3-8). All complexes have been characterised by elemental analysis and NMR spectroscopy, and the molecular structures of complexes 1-5 and 8 are determined by single crystal X-ray diffraction. TG analysis and isothermal TG analysis have been used to evaluate the potential utility of these systems as MOCVD and ALD precursors.

The Effect of Dogs on Human Sleep in the Home Sleep Environment.

OBJECTIVE: To objectively assess whether a dog in the bedroom or bed disturbs sleep. PARTICIPANTS AND METHODS: From August 1, 2015, through December 31, 2015, we evaluated the sleep of humans and dogs occupying the same bedroom to determine whether this arrangement was conducive to sleep. The study included 40 healthy adults without sleep disorders and their dogs (no dogs <6 months old). Each participant wore an accelerometer and their dog a validated dog accelerometer for 7 nights. RESULTS: The mean ± SD age of the participants (88% women) was 44±14 years and body mass index was 25±6. The mean ± SD age of the dogs was 5±3 years and weight was 15±13 kg. Mean ± SD actigraphy data showed 475±101 minutes in bed, 404±99 minutes total sleep time, 81%±7% sleep efficiency, and 71±35 minutes wake time after sleep onset. The dogs' accelerometer activity during the corresponding human sleep period was characterized as mean ± SD minutes at rest, active, and at play of 413±102, 62±43, and 2±4. The dogs had mean ± SD 85%±15% sleep efficiency. Human sleep efficiency was lower if the dog was on the bed as opposed to simply in the room (P=.003). CONCLUSION: Humans with a single dog in their bedroom maintained good sleep efficiency; however, the dog's position on/off the bed made a difference. A dog's presence in the bedroom may not be disruptive to human sleep, as was previously suspected.

The efficacy of continuous positive airway pressure therapy in reducing cardiovascular events in obstructive sleep apnea: a systematic review.

Prospective studies show an association between obstructive sleep apnea and cardiovascular disease. Continuous positive airway pressure (CPAP) is the treatment of choice and effectively reduces subjective sleepiness and apneic and hypopneic events. However, randomized trials have not shown a reduction in cardiovascular outcomes with CPAP therapy. We review the past 10 years of randomized trial evidence regarding the therapeutic efficacy of CPAP on cardiovascular outcomes and mortality in adults with obstructive sleep apnea. The majority of studies found no significant improvement in cardiovascular outcomes with CPAP, although many noted nonsignificant benefits. Adjusted analysis in several trials showed significant cardiovascular benefit in those patients with higher CPAP compliance. Existing trials may lack sufficient follow-up and CPAP compliance, among other limitations.

Aerosol-assisted CVD of SnO from stannous alkoxide precursors.

The stannous alkoxides [Sn(OR)2] [R = i-Pr, t-Bu, C(Et)Me2, CHPh2, CPh3] have been synthesised by reaction of Sn(NR'2)2 with two equivalents of HOR [R' = Me, R = i-Pr; R' = SiMe3, R = t-Bu, C(Et)Me2, CHPh2, CPh3]. Single crystal X-ray diffraction analysis of the bis(diphenylmethoxide) (4) and bis(triphenylmethoxide) (5) species have shown them to comprise three-coordinate Sn(ii) centres through dimerisation in the solid state with the alkoxide units adopting transoid and cisoid configurations across the {Sn2O2} cores respectively. Thermogravimetric analysis indicates clean decomposition and some evidence of volatility at temperatures >200 °C for all three aliphatic alkoxides, whereas both the diphenyl- and triphenylmethoxide compounds provide higher decomposition temperatures and, for the triphenylmethoxide derivative, a residual mass consistent with the formation of a carbon-containing residue. The previously reported iso-propoxide (1) and tert-butoxide (2) derivatives have been utilised in toluene solution to deposit SnO thin films by aerosol-assisted chemical vapour deposition (AACVD) on glass at temperatures between 300 and 450 °C. While SnO is deposited under hot wall conditions as the only identifiable phase by p-XRD and Raman spectroscopy for both precursors, morphological analysis by SEM reveals inferior substrate coverage in comparison to previously reported ureide-based precursor systems.

Pulmonary Epithelioid Hemangioendothelioma Diagnosed With Endobronchial Biopsies: A Case Report and Literature Review.

Pulmonary epithelioid hemangioendothelioma (PEHE) is a rare vascular tumor of endothelial origin first described in 1975 as intravascular bronchioloalveolar tumor. Since then, >100 cases have been reported, and most cases require surgical lung biopsy for diagnosis. We report the case of a 46-year-old man with a diagnosis of PEHE from endobronchial biopsies of an intraluminal nodule, a rare presentation of this disease. We summarize a review of the literature and the bronchoscopic findings of PEHE.

Suvorexant: a promising, novel treatment for insomnia.

Suvorexant a novel, orexin receptor antagonist was recently approved by the US Food and Drug Administration for the treatment of sleep onset and sleep maintenance insomnia in August 2014. Multiple animal and human studies support the efficacy, safety, and tolerability of suvorexant for patients of various profiles. Current recommendations advocate for a starting dose of 10 mg and a maximum dose of 20 mg, with cautious use in women, obese patients, and patients taking other CYP3A4 inhibitors. More head-to-head studies comparing suvorexant to other sedative-hypnotic therapies are needed to further delineate which patients will benefit the most from this medication over others.

Validating the Diagnostic Accuracy of the Sleep Apnea Clinical Score for Use in Primary Care Populations.

OBJECTIVE: To provide external validation of the diagnostic accuracy of the Sleep Apnea Clinical Score (SACS) tool in a new setting and patient population. PATIENTS AND METHODS: We conducted a prospective cohort study. Potential participants were adult family medicine patients. We excluded patients with a SACS of 0, known obstructive sleep apnea (OSA), negative results of previous testing, or life-limiting conditions. After SACS determination, participants completed overnight oximetry, sleep medicine consultation, and polysomnography. Those interpreting tests were blind to the participant's SACS. We determined likelihood ratios (LRs) for OSA diagnosis and posttest probabilities (PTPs). We calculated OSA prevalence (pretest probability), sensitivity, specificity, and positive and negative predictive values. RESULTS: One hundred ninety-one of 312 participants (61%) completed all steps. The prevalence of OSA was similar to that found in the derivation cohort (40% vs 45%; P=.31). With OSA defined as Apnea Hypopnea Index greater than 10, a SACS greater than 15 was 40% sensitive and 90% specific, with a positive predictive value of 73% and a negative predictive value of 69%. A SACS greater than 15 in our cohort produced an LR of 4.03 (95% CI, 3.12-5.22) with 73% PTP for OSA as compared with an LR of 5.17 (95% CI, 2.54-10.51) with 78% PTP found in the derivation cohort. CONCLUSION: The present study provides external validation of the SACS tool. It reliably predicted OSA for patients in our family medicine practice. Broader implementation in primary care practice is recommended. Further study will examine SACS uptake by clinicians and the resulting impact on utilization and clinical efficiency in primary care practices.