COORDINATION AND STRUCTURE OF LATE TRANSITION METAL CATION (Co, Rh, Pt) ACETYLENE COMPLEXES STUDIED WITH INFRARED PHOTODISSOCIATION SPECTROSCOPY

Late transition metals are studied as model systems for single atom catalysis in the gas phase with infrared photodissociation spectroscopy. Clusters of M$^{+}$(acetylene)$_{n}$ (n = 1-8) are produced via laser vaporization of either cobalt, rhodium, or platinum rods in a supersonic expansion of argon containing acetylene. Infrared photodissociation spectroscopy of smaller clusters is accomplished with the aid of argon tagging. Larger clusters are studied through the elimination of one or more acetylene ligands. These spectra are assigned with the aid of B3LYP/Def2TZVP computations. The structure and size of the inner coordination sphere is discussed

SINGLE ATOM CATALYTIC CYCLOTRIMERIZATION OF V(ACETYLENE)3+ STUDIED WITH INFRARED SPECTROSCOPY

Vanadium cation is studied as a model system for single atom catalysis in the gas phase with infrared photodissociation spectroscopy. Intermediates in the cyclotrimerization of acetylene to form benzene are observed. V(C$_{2}$H$_{2}$)$_{n}$$^{+}$ clusters are produced via laser vaporization of vanadium in a supersonic expansion of argon containing acetylene. Clusters of V(C$_{2}$H$_{2}$)$^{+}$, V(C$_{2}$H$_{2}$)$_{2}$$^{+}$, and V(C$_{2}$H$_{2}$)$_{3}$$^{+}$ are studied with infrared photodissociation spectroscopy with the aid of argon tagging in the C–H stretching region. These spectra are assigned on the basis of B3LYP computations. V(C$_{2}$H$_{2}$)$^{+}$ is a three membered metallacycle, where the hydrogens bend away from the vanadium. V(C$_{2}$H$_{2}$)$_{2}$$^{+}$ is a bimetallacycle where both acetylene ligands interact with vanadium symmetrically through their $\pi$-bonds in a C$_{2v}$ configuration. The structure of V(C$_{2}$H$_{2}$)$_{3}$$^{+}$ is found to vary with the concentration of acetylene in the supersonic expansion. At low concentrations of acetylene two isomers of V(C$_{2}$H$_{2}$)$_{3}$$^{+}$ are observed, a trimetallacycle, and a bimetallacycle which includes a five membered ring and a three membered ring. As the concentration of acetylene is increased past 5\% the trimetallacycle decreases in abundance. Benzene is observed at yet higher concentration of acetylene. An expansion gas consisting of 15\% acetylene in argon results in the exclusive formation of V(Bz)$^{+}$

INFRARED SPECTROSCOPY OF Zn(ACETYLENE)1−5+: EVIDENCE OF ACETYLENE ACTIVATION BY A METAL RADICAL

Zinc cation is studied as a model system for single atom catalysis in the gas phase with infrared photodissociation spectroscopy. Zn(C$_{2}$H$_{2}$)$_{n}$$^{+}$ (n = 1–5) clusters are produced via laser vaporization of zinc in a supersonic expansion of acetylene and argon. Clusters are mass-selected and studied with infrared photodissociation spectroscopy in the C–H stretching region. Smaller clusters (n = 1–3) are studied with the use of a weakly bound argon tag. These spectra are assigned with B3LYP/Def2TZVP computational studies. Zn(C$_{2}$H$_{2}$)$^{+}$ is found to consist of a C$_{2v}$ three membered metallacycle, where zinc is equidistant from both carbon atoms of acetylene. Zn(C$_{2}$H$_{2}$)$_{2}$$^{+}$ does not contain a metallacycle, but features zinc binding more closely to one of the carbon atoms of each acetylene in a C$_{2}$ configuration. The three-coordinate cluster is predicted to be lowest in energy as a $\pi$-bound D$_{3h}$ structure, with a low energy C$_{3}$ structure. When the spectrum of this cluster is measured with argon tagging the D$_{3h}$ isomer is most abundant. When measured without the tag the C$_{3}$ isomer is found to be in abundance. The spectra of the four and five coordinate clusters are found to contain a feature 160 cm$^{-1}$ to the red of the acetylene C–H asymmetric stretch. This is attributed to a fourth acetylene ligand forming a metal vinyl radical, accompanied by formation of Zn(II). This transfer of the radical center from zinc to a ligand activates the acetylene, and could be the first step in single atom catalysis by zinc

INFRARED PHOTODISSOCIATION SPECTROSCOPY OF Co+(H2O)RG WITH He, Ne, AND Ar RARE GAS TAGGING.

Complexes of Co$^{+}$(H$_{2}$O) and Co$^{+}$(D$_{2}$O) are produced via laser vaporization of cobalt metal in a supersonic expansion of rare gas seeded with water. Infrared photodissociation spectroscopy is accomplished with the aid of rare gas tagging by He, Ne, or Ar. The effect of Co+ on the ortho-para nuclear spin statistics of H$_{2}$O and D$_{2}$O are investigated. The OH stretching frequencies of water were found to red shift by about 40 \wn, and the water bending mode was found to blue shift by 23 \wn. Rotational resolution was achieved for helium tagged water complex. The combined effect of spin-orbit coupling and spin-rotation coupling in these complexes is discussed and compared to the previously studied systems Sc$^{+}$(H$_{2}$O) and Ti$^{+}$(H$_{2}$O). Electronic structure calculations with CASSCF/cc-pVTZ were used to determine the single reference character of the ground electronic state. MN15/cc-pVTZ was used to compute vibrational frequencies

Preparation of methanediamine (CH2(NH2)2)—A precursor to nucleobases in the interstellar medium

Although methanediamine (CH2(NH2)2) has historically been the subject of theoretical scrutiny, it has never been isolated to date. Here, we report the preparation of methanediamine (CH2(NH2)2)—the simplest diamine. Low-temperature interstellar analog ices composed of ammonia and methylamine were exposed to energetic electrons which act as proxies for secondary electrons produced in the track of galactic cosmic rays. These experimental conditions, which simulate the conditions within cold molecular clouds, . result in radical formation and initiate aminomethyl (ĊH2NH2) and amino (NH2) radical chemistry. Exploiting tunable photoionization reflectron time-of-flight mass spectrometry (PI-ReToF-MS) to make isomer-specific assignments, methanediamine was identified in the gas phase upon sublimation, while its isomer methylhydrazine (CH3NHNH2) was not observed. The molecular formula was confirmed to be CH6N2 through the use of isotopically labeled reactants. Methanediamine is the simplest molecule to contain the NCN moiety and could be a vital intermediate in the abiotic formation of heterocyclic and aromatic systems such as nucleobases, which all contain the NCN moiety

Thrust joint manipulation education: Student perceptions of learning and practical experiences in spinal manipulation within entry-level physical therapist education programs

Background: Spinal thrust joint manipulation (TJM) education is mandatory in all professional entry-level physical therapy programs, yet TJM is under-utilized in daily practice. This descriptive study expands on previous data about how TJM is taught and includes data for the perceived confidence students have when performing TJM. Methods: A 39-question descriptive survey inquiring about TJM education and selfperceived confidence in performing TJM was distributed via email to 213 accredited physical therapy programs. Subjects: Respondents ranged in age from 22-45 (mean age=25.61 years). Respondents included 435 professional physical therapy students (84 male, 285 female) who have completed their didactic classes. All participants have completed professional didactic coursework from an accredited physical therapy program in the United States. Results: Survey results showed that laboratory instruction resulted in more confidence in performing TJM and identifying those likely to respond to TJM than not having the information covered. Several classes of instruction, as opposed to only one class, were more beneficial for confidence levels in identification and performance of TJM. Receiving a TJM benefitted confidence levels performing TJM as well. Conclusion: No method of instruction type or time leads to more confidence in identifying those likely to benefit from TJM or more confidence in applying TJM. Experiencing a TJM resulted in an increased confidence to perform TJM. Spinal manipulation has been shown to be an effective treatment method and is beneficial to those for whom it is clinically indicated. Since, according to research, TJM is underutilized in clinical practice, it is important to understand how students are taught manipulation techniques

Estimated clinical outcomes and cost-effectiveness associated with provision of addiction treatment in US primary care clinics

IMPORTANCE: US primary care practitioners (PCPs) are the largest clinical workforce, but few provide addiction care. Primary care is a practical place to expand addiction services, including buprenorphine and harm reduction kits, yet the clinical outcomes and health care sector costs are unknown. OBJECTIVE: To estimate the long-term clinical outcomes, costs, and cost-effectiveness of integrated buprenorphine and harm reduction kits in primary care for people who inject opioids. DESIGN, SETTING, AND PARTICIPANTS: In this modeling study, the Reducing Infections Related to Drug Use Cost-Effectiveness (REDUCE) microsimulation model, which tracks serious injection-related infections, overdose, hospitalization, and death, was used to examine the following treatment strategies: (1) PCP services with external referral to addiction care (status quo), (2) PCP services plus onsite buprenorphine prescribing with referral to offsite harm reduction kits (BUP), and (3) PCP services plus onsite buprenorphine prescribing and harm reduction kits (BUP plus HR). Model inputs were derived from clinical trials and observational cohorts, and costs were discounted annually at 3%. The cost-effectiveness was evaluated over a lifetime from the modified health care sector perspective, and sensitivity analyses were performed to address uncertainty. Model simulation began January 1, 2021, and ran for the entire lifetime of the cohort. MAIN OUTCOMES AND MEASURES: Life-years (LYs), hospitalizations, mortality from sequelae (overdose, severe skin and soft tissue infections, and endocarditis), costs, and incremental cost-effectiveness ratios (ICERs). RESULTS: The simulated cohort included 2.25 million people and reflected the age and gender of US persons who inject opioids. Status quo resulted in 6.56 discounted LYs at a discounted cost of $203 500 per person (95$203 000-$222 000). Each strategy extended discounted life expectancy: BUP by 0.16 years and BUP plus HR by 0.17 years. Compared with status quo, BUP plus HR reduced sequelae-related mortality by 33$34 400 per LY). During a 5-year time horizon, BUP plus HR cost an individual PCP practice approximately $13 000. CONCLUSIONS AND RELEVANCE: This modeling study of integrated addiction service in primary care found improved clinical outcomes and modestly increased costs. The integration of addiction service into primary care practices should be a health care system priority