Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 27
Filter
1.
Environ Entomol ; 52(5): 918-938, 2023 Oct 16.
Article in English | MEDLINE | ID: mdl-37681665

ABSTRACT

Mounting evidence of bumble bee declines and the listing of the rusty patched bumble bee (Bombus affinis Cresson) as federally endangered in the United States in 2017 and Canada in 2012 has stimulated an interest in monitoring and conservation. Understanding the influence of land use on occupancy patterns of imperiled species is crucial to successful recovery planning. Using detection data from community surveys, we assessed land use associations for 7 bumble bee species in Minnesota, USA, including B. affinis. We used multispecies occupancy models to assess the effect of 3 major land use types (developed, agricultural, and natural) within 0.5 and 1.5 km on occupancy of 7 Bombus (Hymenoptera: Apidae) species, while accounting for detection uncertainty. We found that B. affinis occupancy and detection were highest in developed landscapes and lowest in agricultural landscapes, representing an inverse relationship with the relative landcover ratios of these landscapes in Minnesota. Occupancy of 2 bumble bee species had strong positive associations with natural landscapes within 1.5 km and 2 species had strong negative associations with agricultural landscapes within 1.5 km. Our results suggest that best practices for imperiled Bombus monitoring and recovery planning depends upon the surrounding major land use patterns. We provide recommendations for urban planning to support B. affinis based on conservation success in the metropolitan areas of Minneapolis-St. Paul. We also encourage substantial survey effort be employed in agricultural and natural regions of the state historically occupied by B. affinis to determine the current occupancy state.

2.
Zootaxa ; 5304(1): 1-95, 2023 Jun 16.
Article in English | MEDLINE | ID: mdl-37518539

ABSTRACT

Research studies and conservation actions aimed at improving conditions for bees require a basic understanding of which species are present in a given region. The US state of Minnesota occupies a unique geographic position at the confluence of eastern deciduous forests, northern boreal forests, and western tallgrass prairie, which has led to a diverse and unique bee fauna. In recent years there have been multiple ongoing bee-focused inventory and research projects in Minnesota. Combined with the historic specimens housed in the University of Minnesota Insect Collection and other regional collections, these furnished a wealth of specimens available to form the basis of a statewide checklist. Here, we present the first comprehensive checklist of Minnesota bee species, documenting a total of 508 species in 45 genera. County-level occurrence data is included for each species, and further information on distribution and rarity is included for species of regional or national interest. Some species have their taxonomy clarified, with Perdita citrinella Graenicher, 1910 syn. nov. recognized as a junior synonym of Perdita perpallida Cockerell, 1901, P. bequaerti syn. nov. recognized as a junior synonym of P. pallidipennis Graenicher, 1910 stat. nov., Anthidiellum boreale (Robertson, 1902) stat. nov. recognized as a full species, and Anthidiellium beijingense Portman & Ascher nom. nov. is proposed for A. boreale Wu to resolve the homonymy with A. boreale (Robertson). We further include a list of species that may occur in Minnesota and highlight 11 species occurring in the state that are considered non-native. Recent collecting efforts, as well as increased taxonomic attention paid to Minnesota bees, have resulted in 66 species that have only been documented in the last 10 years. As a first step in determining native bees of conservation concern, we document 38 species that have not been detected in the state during the last 50 years and discuss their conservation status, along with other species for which evidence of decline exists. The checklist of Minnesota bees will continue to grow and change with additional surveys and research studies. In particular, recent surveys have continued to detect new bee species, and many bee groups are in need of taxonomic revision, with the most recent revisions for many genera occurring decades ago. Overall, this checklist strengthens our understanding of the bees of Minnesota and the broader region, informs conservation assessments, and establishes a baseline for faunal change.


Subject(s)
Hymenoptera , Bees , Animals , Minnesota , Animal Distribution , Forests , Taiga
4.
J Dual Diagn ; 19(1): 40-48, 2023.
Article in English | MEDLINE | ID: mdl-36576889

ABSTRACT

Background: The current study aimed to understand how people with mental health conditions who currently smoke or recently quit engaged with family members or peers when quitting and assessed interest in involving family or peers in cessation interventions. Methods: Adults with mental health conditions who smoke or had quit within the past 5 years were recruited from publicly funded mental health programs (N = 24). We conducted virtual qualitative interviews between November 2020 and August 2021 and analyzed the data using the rapid thematic analytic approach. Results: Most participants were men (62%), and 71% were current smokers. We found that: having family/peers who were interested in quitting presented communal quitting opportunities, communication that facilitated quitting tended to be encouraging, and strong relationships with family members increased willingness to involve them in cessation interventions. But family or peer support was less helpful for individuals who were not ready to quit. Conclusion: Training family and peers to engage in supportive behaviors may promote cessation in this population. Cessation interventions may benefit from recruiting support partners who share a strong relationship with the smoker.


Subject(s)
Mental Disorders , Smoking Cessation , Male , Adult , Humans , Female , Smoking Cessation/psychology , Mental Health , Qualitative Research , Health Behavior , Mental Disorders/complications , Mental Disorders/therapy , Mental Disorders/psychology
5.
Int J Mol Sci ; 23(24)2022 Dec 08.
Article in English | MEDLINE | ID: mdl-36555224

ABSTRACT

Novel sulfur and selenium substituted 5',5'-linked dinucleoside pyrophate analogues were prepared in a vibration ball mill from the corresponding persilylated monophosphate. The chemical hydrolysis of pyrophosphorochalcogenolate-linked dimers was studied over a wide pH-range. The effect of the chalcogeno-substitution on the reactivity of dinucleoside pyrophosphates was surprisingly modest, and the chemical stability is promising considering the potential therapeutic or diagnostic applications. The chemical stability of the precursor phosphorochalcogenolate monoesters was also investigated. Hydrolytic desilylation of these materials was effected in aqueous buffer at pH 3, 7 or 11 and resulted in phosphorus-chalcogen bond scission which was monitored using 31P NMR. The rate of dephosphorylation was dependent upon both the nature of the chalcogen and the pH. The integrity of the P-S bond in the corresponding phosphorothiolate was maintained at high pH but rapidly degraded at pH 3. In contrast, P-Se bond cleavage of the phosphoroselenolate monoester was rapid and the rate increased with alkalinity. The results obtained in kinetic experiments provide insight on the reactivity of the novel pyrophosphates studied as well as of other types of thiosubstituted biological phosphates. At the same time, these results also provide evidence for possible formation of unexpectedly reactive intermediates as the chalcogen-substituted analogues are metabolised.


Subject(s)
Chalcogens , Nucleosides , Phosphates/chemistry , Hydrolysis , Diphosphates/chemistry
6.
JMIR Form Res ; 6(11): e40907, 2022 Nov 07.
Article in English | MEDLINE | ID: mdl-36342765

ABSTRACT

BACKGROUND: People with serious mental illness are disproportionately affected by smoking and face barriers to accessing smoking cessation treatments in mental health treatment settings. Text-based interventions are cost-effective and represent a widely accessible approach to providing smoking cessation support. OBJECTIVE: We aimed to identify key factors for adapting text-based cessation interventions for people with serious mental illness who smoke. METHODS: We recruited 24 adults from mental health programs who had a serious mental illness and currently smoked cigarettes or had quit smoking within the past 5 years. We then conducted virtual qualitative interviews between November 2020 and August 2021. Data were analyzed using the rapid thematic analytic approach. RESULTS: We identified the following 3 major themes: (1) interplay between smoking and having a serious mental illness, (2) social contextual factors of smoking in adults with serious mental illness, and (3) smoking and quitting behaviors similar to the general population. Participants reported barriers and facilitators to quitting across the 3 themes. Within the "interplay between smoking and having a serious mental illness" theme, barriers included smoking to manage stress and mental health symptoms, and facilitators to quitting included the awareness of the harm of smoking on mental health and patient-provider discussions on smoking and mental health. In the "social contextual factors of smoking in adults with serious mental illness" theme, barriers included high social acceptability of smoking among peers. Positive support and the combined social stigma of smoking and having a mental health condition outside of peer groups motivated individuals to quit. Some participants indicated that low exposure to other smokers during the COVID-19 pandemic helped them to engage in cessation efforts. In the "smoking and quitting behaviors similar to the general population" theme, barriers included smoking after eating, having coffee, drinking alcohol, and experiencing negative social support, and facilitators included health concerns, improvement in the general quality of life, and use of evidence-based tobacco treatments when available. CONCLUSIONS: People with serious mental illness often smoke to cope with intense emotional states, manage mental health symptoms, or maintain social bonds. Text message content emphasizing equally effective and less harmful ways for stress reduction and mental health symptom management may improve quit rates in individuals with serious mental illness.

7.
Front Psychiatry ; 13: 814185, 2022.
Article in English | MEDLINE | ID: mdl-35370850

ABSTRACT

In recent decades the average age of becoming a parent has increased, the rate of teen pregnancies has decreased, and a new developmental period of emerging adulthood is marked by diverse pathways into adulthood. Today, those who become parents in young adulthood (18-24 years old) and their children may be vulnerable to poor outcomes observed in teen parents (13-19 years old) of previous generations. Young adults with serious mental health conditions (SMHC) who encounter additional challenges navigating young adulthood and tend to parent earlier than their peers may be at particularly increased risk of poor outcomes. To date, little research has been done to understand the experiences of young adult parents, especially those with SMHC. This study describes themes from qualitative interviews with 18 young adults with SMHC in the United States who became parents before the age of 25. Life story narrative interviews, conducted mostly by young adults with lived experience, asked participants to describe their parenting and mental health experiences and their school, training, and work experiences. Participants described the challenges of simultaneously parenting young children and managing a mental health condition, experiences of discrimination, and fear of future discrimination related to their mental health condition. However, parents also expressed that their children motivated them to maintain recovery and build a good life for their family. This is the first study to qualitatively explore the experiences of young adult parents with SMHC. While many of these findings align with prior qualitative research on mothers with mental illness, by exclusively focusing on individuals who become parents earlier than their peers and including father experiences, this research adds to our understanding of how individuals simultaneously navigate parenting and managing a serious mental health condition. These findings should inform larger-scale research studies on the experiences and outcomes of young adults with SMHC who become parents in their late teens or early twenties. A better understanding of their experiences should inform public mental health services that incorporate parenting as an important element of an individual's personal recovery model.

8.
Psychiatr Serv ; 73(7): 787-800, 2022 07.
Article in English | MEDLINE | ID: mdl-34875848

ABSTRACT

OBJECTIVE: The authors conducted a systematic review of studies evaluating vocational interventions for young people with psychiatric conditions to determine the extent to which services were adapted for young people and whether services promoted gains in postsecondary education and employment. METHODS: Five databases (PubMed, PsycINFO, Web of Science, Academic Search Premier, and ERIC) were searched. Sources eligible for inclusion were controlled studies published between 2000 and mid-2020 that evaluated a vocational intervention and examined postsecondary educational or employment outcomes for youths or young adults (ages 14-35 years) with psychiatric conditions. RESULTS: Ten studies met the inclusion criteria. Several of the studies evaluated services that were adapted for young people, including through the incorporation of educational supports. The most consistent finding was that services based on the individual placement and support (IPS) model improved employment outcomes more effectively than did comparison approaches and treatment as usual. Fewer studies assessed educational outcomes, and they yielded mixed results; however, recent findings from a controlled trial indicate that an enhanced IPS intervention that included well-specified supported education and skills training led to significantly superior outcomes in both education and employment. CONCLUSIONS: These results provide support for the efficacy of IPS-based services to improve employment outcomes among young people with psychiatric conditions and suggest that adapting IPS to include comprehensive educational supports and skills training may be important for efforts to improve postsecondary educational outcomes. Additional well-controlled intervention studies that examine educational and longer-term outcomes should further inform the development and delivery of vocational services for this population.


Subject(s)
Employment, Supported , Mental Disorders , Adolescent , Adult , Educational Status , Humans , Mental Disorders/therapy , Rehabilitation, Vocational/methods , Young Adult
9.
Zookeys ; 1130: 103-152, 2022.
Article in English | MEDLINE | ID: mdl-36761018

ABSTRACT

Augochloropsis and other shiny green Halictinae have had various taxonomic issues and are often misidentified. One prevailing taxonomic issue is that Augochloropsismetallica (Fabricius) has two subspecies, that have long been recognized as morphologically distinct (Augochloropsismetallicametallica and Augochloropsismetallicafulgida (Smith), but the subspecies are inconsistently applied in the literature. Here, we review the Augochloropsis of the Midwest and further address the Augochloropsis species in the broader United States to resolve the outstanding taxonomic issues with the midwestern species. We provide identification keys and diagnoses for the genera and species of the shiny green Halictinae of the midwestern United States, which includes the genera Agapostemon, Augochlora, Augochlorella, and Augochloropsis. This work results in taxonomic changes to Augochloropsis. Augochloropsissumptuosa (Smith) is split into two species, with the name Augochloropsissumptuosa retained for the eastern form, and Augochloropsishumeralis (Patton), stat. nov., reinstated for the western form. Augochloropsismetallica is split into five species, with two of those species occurring in the midwestern United States: Augochloropsismetallica and Augochloropsisviridula (Smith), stat. nov. Examination of the holotype of Augochloropsisfulgida (Smith) revealed that it does not agree with the prevailing concept of Augochloropsismetallicafulgida; it is reinstated as Augochloropsisfulgida, stat. nov., but is currently known only from the holotype female from Florida. Augochloropsiscuprea (Smith), long considered to be a synonym of Augochloropsismetallica, is also distinct, and we are reinstating Augochloropsiscuprea, stat. nov., though the range of this species is unclear. We further recognize Augochloropsisfulvofimbriata (Friese), stat. nov., from South and Central America, as distinct. These changes result in a total of three Augochloropsis species in the Midwest and seven named species in the United States. We are aware of additional species from the southern and southwestern United States that are undescribed, and we highlight additional taxonomic work that remains to be done.

10.
Mil Med ; 182(S1): 32-40, 2017 03.
Article in English | MEDLINE | ID: mdl-28291449

ABSTRACT

This article forms part of a series that will explore the effect that Role 2 (R2) medical treatment facilities (MTFs) had on casualty care during the military campaign in Afghanistan and how we should interpret this to inform the capabilities in, and training for future R2 MTFs. Key aspects of doctrine which influence the effectiveness of R2 MTFs include timelines to care, patient movement capabilities, and MTF capabilities. The focus of this analysis was to review allied doctrine from the United States, United Kingdom, and the North Atlantic Treaty Organization to identify similarities and differences regarding employment of R2 related medical assets in the Afghan Theater, specifically for trauma care. Several discrepancies in medical doctrine persist among allied forces. Timelines to definitive care vary among nations. Allied nations should have clear taxonomy that clearly defines MTF capabilities within the combat casualty care system. The R2 surgical capability discrepancy between United States and North Atlantic Treaty Organization doctrine should be reconciled. Medical evacuation capabilities on the battlefield would be improved with a taxonomy that reflected the level of capability. Such changes may improve interoperability in a dynamic military landscape.


Subject(s)
Afghan Campaign 2001- , Delivery of Health Care/methods , Health Policy/history , Military Medicine/methods , Delivery of Health Care/standards , History, 21st Century , Humans , International Cooperation/history , Military Medicine/standards , Time Factors , United States
11.
Inorg Chem ; 56(10): 5577-5585, 2017 May 15.
Article in English | MEDLINE | ID: mdl-28240882

ABSTRACT

Tolyporphins are glycosylated macrocycles isolated from lipophilic soil extracts of the cyanobacterium, Tolypothrix nodosa, and found to potentiate the cytotoxicity of antitumor drugs like vinblastine and adriamycin. Here we find that, unlike porphyrins, tolyporphins are not able to form complexes with most metal ions. However, they do react strongly with copper(II) and silver(II), forming square-planar metal complexes with an unpaired electron in a dx2-y2 orbital of the metal delocalized onto the ligating tolyporphin nitrogen atoms. Complexes were characterized by visible absorption spectra, mass spectrometry (EI, FAB, ESI, LDI-TOF, and MALDI-TOF) and multifrequency continuous-wave electron paramagnetic resonance spectra. Copper(II) and silver(II) complexes of tolyporphins A and E were found to have the interesting property of reversing multidrug resistance (MDR), with the copper complexes being less toxic than free tolyporphins. Reactive oxygen-free radicals were implicated in both the cytotoxic and MDR-reversing effects of free and metalated tolyporphins.


Subject(s)
Antineoplastic Agents/pharmacology , Coordination Complexes/pharmacology , Copper/pharmacology , Cyanobacteria/chemistry , Macrocyclic Compounds/pharmacology , Porphyrins/pharmacology , Silver/pharmacology , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Binding Sites , Cell Proliferation/drug effects , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Copper/chemistry , Dose-Response Relationship, Drug , Drug Resistance, Multiple/drug effects , Drug Resistance, Neoplasm/drug effects , Drug Screening Assays, Antitumor , Humans , Macrocyclic Compounds/chemistry , Molecular Structure , Porphyrins/chemistry , Silver/chemistry , Structure-Activity Relationship , Tumor Cells, Cultured
12.
J Chem Phys ; 144(14): 144314, 2016 Apr 14.
Article in English | MEDLINE | ID: mdl-27083728

ABSTRACT

BaH (and its isotopomers) is an attractive molecular candidate for laser cooling to ultracold temperatures and a potential precursor for the production of ultracold gases of hydrogen and deuterium. The theoretical challenge is to simulate the laser cooling cycle as reliably as possible and this paper addresses the generation of a highly accurate ab initio (2)Σ(+) potential for such studies. The performance of various basis sets within the multi-reference configuration-interaction (MRCI) approximation with the Davidson correction is tested and taken to the Complete Basis Set (CBS) limit. It is shown that the calculated molecular constants using a 46 electron effective core-potential and even-tempered augmented polarized core-valence basis sets (aug-pCVnZ-PP, n = 4 and 5) but only including three active electrons in the MRCI calculation are in excellent agreement with the available experimental values. The predicted dissociation energy De for the X(2)Σ(+) state (extrapolated to the CBS limit) is 16,895.12 cm(-1) (2.094 eV), which agrees within 0.1% of a revised experimental value of <16,910.6 cm(-1), while the calculated re is within 0.03 pm of the experimental result.

13.
J Trauma Acute Care Surg ; 81(5 Suppl 2 Proceedings of the 2015 Military Health System Research Symposium): S121-S127, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27120324

ABSTRACT

BACKGROUND: A Role 2 registry (R2R) was developed in 2008 by the US Joint Trauma System (JTS). The purpose of this project was to undertake a preliminary review of the R2R to understand combat trauma epidemiology and related interventions at these facilities to guide training and optimal use of forward surgical capability in the future. METHODS: A retrospective review of available JTS R2R records; the registry is a convenience sample entered voluntarily by members of the R2 units. Patients were classified according to basic demographics, affiliation, region where treatment was provided, mechanism of injury, type of injury, time and method of transport from point of injury (POI) to R2 facility, interventions at R2, and survival. Analysis included trauma patients aged ≥18 years or older wounded in year 2008 to 2014, and treated in Afghanistan. RESULTS: A total of 15,404 patients wounded and treated in R2 were included in the R2R from February 2008 to September 2014; 12,849 patients met inclusion criteria. The predominant patient affiliations included US Forces, 4,676 (36.4%); Afghan Forces, 4,549 (35.4%); and Afghan civilians, 2,178 (17.0%). Overall, battle injuries predominated (9,792 [76.2%]). Type of injury included penetrating, 7,665 (59.7%); blunt, 4,026 (31.3%); and other, 633 (4.9%). Primary mechanism of injury included explosion, 5,320 (41.4%); gunshot wounds, 3,082 (24.0%); and crash, 1,209 (9.4%). Of 12,849 patients who arrived at R2, 167 (1.3%) were dead; of 12,682 patients who were alive upon arrival, 342 (2.7%) died at R2. CONCLUSION: This evaluation of the R2R describes the patient profiles of and common injuries treated in a sample of R2 facilities in Afghanistan. Ongoing and detailed analysis of R2R information may provide evidence-based guidance to military planners and medical leaders to best prepare teams and allocate R2 resources in future operations. Given the limitations of the data set, conclusions must be interpreted in context of other available data and analyses, not in isolation. LEVEL OF EVIDENCE: Epidemiologic study, level IV.


Subject(s)
Military Medicine , Military Personnel , Registries , Traumatology/statistics & numerical data , Wounds and Injuries/epidemiology , Afghan Campaign 2001- , Humans , Military Personnel/statistics & numerical data , Retrospective Studies , United States
14.
Ann Vasc Surg ; 27(8): 1207-15, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23850312

ABSTRACT

BACKGROUND: Since its original description in the British Medical Journal in 1978, the treatment of lymphatic fistulas in the groin remains contentious. Lymph leaks remain a common cause of morbidity in patients who have undergone groin dissection. The aim of this review was to examine the evidence for prevention and treatment of lymphatic fistulas after arterial surgery in the groin. METHODS: A systematic review of the English language literature was undertaken to determine the success of the various treatment options described. RESULTS: A comprehensive literature search identified 46 studies describing several treatment options for lymphatic fistulas. A qualitative synthesis of these studies was performed. There was no consensus definition of lymphatic fistula. Treatments reviewed were: conservative management; lymphatic ligation; vascularized muscle flaps; and negative pressure wound therapy (NPWT). Due to poor study quality and the paucity of data no one treatment could be identified as superior. CONCLUSIONS: There was no quantifiable cut-off for either the amount of lymphatic output or number of days postoperatively that leakage continued to help determine when conservative measures should be abandoned and surgical intervention undertaken. There is some evidence supporting use of vascularized muscle flaps to reduce the volume of lymphatic drainage and help prevent secondary graft infection. The use of NPWT is also promising, but must be weighed against the associated risk of anastomotic bleeding and requirement for additional inpatient stay.


Subject(s)
Fistula/therapy , Groin/blood supply , Lymphatic Diseases/therapy , Negative-Pressure Wound Therapy , Plastic Surgery Procedures/adverse effects , Surgical Flaps/blood supply , Vascular Surgical Procedures/adverse effects , Arteries/surgery , Fistula/diagnosis , Fistula/etiology , Fistula/surgery , Humans , Length of Stay , Ligation , Lymphatic Diseases/diagnosis , Lymphatic Diseases/etiology , Lymphatic Diseases/surgery , Negative-Pressure Wound Therapy/adverse effects , Patient Selection , Reoperation , Risk Factors , Time Factors , Treatment Outcome
15.
Phys Chem Chem Phys ; 14(43): 15078-87, 2012 Nov 21.
Article in English | MEDLINE | ID: mdl-23034675

ABSTRACT

Large parts of the periodic table cannot be cooled by current laser-based methods. We investigate whether zero energy fragmentation of laser cooled fluorides is a potential source of ultracold fluorine atoms. We report new ab initio calculations on the lowest electronic states of the BeF diatomic molecule including spin-orbit coupling, the calculated minima for the valence electronic states being within 1 pm of the spectroscopic values. A four colour cooling scheme based on the A(2)Π← X(2)Σ(+) transition is shown to be feasible for this molecule. Multi-Reference Configuration Interaction (MRCI) potentials of the lowest energy Rydberg states are reported for the first time and found to be in good agreement with experimental data. A series of multi-pulse excitation schemes from a single rovibrational level of the cooled molecule are proposed to produce cold fluorine atoms.

16.
J Vasc Surg ; 56(3): 834-8, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22796332

ABSTRACT

The aim of this review was to assess the place of retroperitoneal (RP) aortic surgery for abdominal aortic aneurysms (AAAs) in the endovascular era and evaluate the evidence supporting it in preference to the more traditional transperitoneal approach. As endovascular graft technology improves, open aortic surgery is declining. AAAs unsuitable for endovascular aneurysm repair are, by definition, anatomically challenging. The RP approach is especially suited to anatomic challenges such as those posed by contemporary open AAA because it facilitates access to the suprarenal aorta. There is evidence that the RP approach reduces postoperative morbidity and length of stay compared with transperitoneal approaches. The evidence available indicates that the RP approach should be the first considered for any AAA unsuitable for endovascular aneurysm repair; however, the technique is more difficult to learn and less commonly practiced than the transperitoneal approach. Combined with a decrease in training hours in the United Kingdom, there is a real threat that the RP technique will only be performed by an ever-decreasing number of enthusiasts.


Subject(s)
Aorta, Abdominal/surgery , Aortic Aneurysm, Abdominal/surgery , Blood Vessel Prosthesis Implantation/methods , Endovascular Procedures , Aortic Aneurysm, Abdominal/history , Blood Vessel Prosthesis Implantation/adverse effects , Blood Vessel Prosthesis Implantation/history , Clinical Competence , Endovascular Procedures/adverse effects , Endovascular Procedures/history , Evidence-Based Medicine , History, 20th Century , History, 21st Century , Humans , Learning Curve , Peritoneum/surgery , Retroperitoneal Space/surgery , Treatment Outcome
17.
Phys Chem Chem Phys ; 13(42): 19036-51, 2011 Nov 14.
Article in English | MEDLINE | ID: mdl-21971563

ABSTRACT

Strategies to produce an ultracold sample of carbon atoms are explored and assessed with the help of quantum chemistry. After a brief discussion of the experimental difficulties using conventional methods, two strategies are investigated. The first attempts to exploit charge exchange reactions between ultracold metal atoms and sympathetically cooled C(+) ions. Ab initio calculations including electron correlation have been conducted on the molecular ions [LiC](+) and [BeC](+) to determine whether alkali or alkaline earth metals are a suitable buffer gas for the formation of C atoms but strong spontaneous radiative charge exchange ensure they are not ideal. The second technique involves the stimulated production of ultracold C atoms from a gas of laser cooled carbides. Calculations on LiC suggest that the alkali carbides are not suitable but the CH radical is a possible laser cooling candidate thanks to very favourable Frank-Condon factors. A scheme based on a four pulse STIRAP excitation pathway to a Feshbach resonance is outlined for the production of atomic fragments with near zero centre of mass velocity.

18.
Phys Chem Chem Phys ; 13(42): 19018-25, 2011 Nov 14.
Article in English | MEDLINE | ID: mdl-21842049

ABSTRACT

The feasibility of laser cooling AlH and AlF is investigated using ab initio quantum chemistry. All the electronic states corresponding to the ground and lowest two excited states of the Al atom are calculated using multi-reference configuration interaction (MRCI) and the large AV6Z basis set for AlH. The smaller AVQZ basis set is used to calculate the valence electronic states of AlF. Theoretical Franck-Condon factors are determined for the A(1)Π→ X(1)Σ(+) transitions in both radicals and found to agree with the highly diagonal factors found experimentally, suggesting computational chemistry is an effective method for screening suitable laser cooling candidates. AlH does not appear to have a transition quite as diagonal as that in SrF (which has been laser cooled) but the A(1)Π→ X(1)Σ(+) transition transition of AlF is a strong candidate for cooling with just a single laser, though the cooling frequency is deep in the UV. Furthermore, the a(3)Π→ X(1)Σ(+) transitions are also strongly diagonal and in AlF is a practical method for obtaining very low final temperatures around 3 µK.

19.
Inorg Chem ; 46(7): 2373-87, 2007 Apr 02.
Article in English | MEDLINE | ID: mdl-17343374

ABSTRACT

Reaction of Tp*MoVSCl2 with a variety of phenols and thiols in the presence of triethylamine produces mononuclear, thiomolybdenyl complexes Tp*MoVSX2 [Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate; X = 2-(ethylthio)phenolate (etp), 2-(n-propyl)phenolate (pp), phenolate; X2 = benzene-1,2-dithiolate (bdt), 4-methylbenzene-1,2-dithiolate (tdt), benzene-1,2-diolate (cat)]. The complexes have been characterized by microanalysis, mass spectrometry, IR, EPR, and UV-visible spectroscopic data, and X-ray crystallography (for the etp, pp, bdt, and cat derivatives). The mononuclear, six-coordinate, distorted-octahedral Mo centers are coordinated by terminal sulfido (MoS = 2.123(1)-2.1368(8) A), tridentate facial Tp*, and monodentate or bidentate O/S-donor ligands. Multifrequency (S-, X-, Q-band) EPR spectra of the complexes and selected molybdenyl analogues were acquired at 130 K and 295 K and yielded a spin Hamiltonian of Cs symmetry or lower, with gzz < gyy < gxx < ge and Az'z' > Ax'x' approximately Ay'y', and a noncoincidence angle in the range of beta = 24-39 degrees . Multifrequency EPR, especially at S-band, was found to be particularly valuable in the unambiguous assignment of the spin Hamiltonian parameters in these low-symmetry complexes. The weaker pi-donor terminal sulfido ligand yields a smaller SOMO-LUMO gap and reduced g-values for the thiomolybdenyl complexes compared with molybdenyl analogues, supporting existing crystallographic and EPR data for an apically coordinated oxo group in the active site of xanthine oxidase.


Subject(s)
Molybdenum/chemistry , Sulfhydryl Compounds/chemistry , Crystallography, X-Ray , Electrochemistry , Electron Spin Resonance Spectroscopy , Electrons , Models, Molecular , Molecular Conformation , Sulfhydryl Compounds/chemical synthesis
20.
J Chem Phys ; 126(2): 024707, 2007 Jan 14.
Article in English | MEDLINE | ID: mdl-17228966

ABSTRACT

We present a set of experiments that provide a complete mapping of coherent and incoherent vibrational relaxation times for a molecule on a metal surface, CO/Ir{111}. Included is the first detection of a midinfrared photon echo from a metallic surface, some 15 years after the analogous measurement on a semiconductor surface, which sets a precedent for the ability to manipulate and rephase polarization on a subpicosecond time scale on surfaces. For the C-O stretch in a strongly dipole-coupled CO layer we obtain a total linewidth of 5.6 cm-1, composed of a homogeneous width of 2.7 cm-1 and an inhomogeneous contribution of 3.0 cm-1. Pure dephasing is negligible at liquid nitrogen temperatures, making CO/Ir{111} an attractive model system for quantum computing.

SELECTION OF CITATIONS
SEARCH DETAIL
...