Single photon ionization of van der Waals clusters with a soft x-ray laser: (CO2)n and (CO2n(H2O)m

Includes bibliographical references (pages 154316-7).Pure neutral (CO2)n clusters and mixed (CO2)n(H2O)m clusters are investigated employing time of flight mass spectroscopy and single photon ionization at 26.5 eV. The distribution of pure (CO2)n clusters decreases roughly exponentially with increasing cluster size. During the ionization process, neutral clusters suffer little fragmentation because almost all excess cluster energy above the vertical ionization energy is taken away by the photoelectron and only a small part of the photon energy is deposited into the (CO2)n cluster. Metastable dissociation rate constants of (CO2)n+ are measured in the range of (0.2-1.5) × 104 s−1 for cluster sizes of 5≤n≤16. Mixed CO2-H2O clusters are studied under different generation conditions (5% and 20% CO2 partial pressures and high and low expansion pressures). At high CO2 concentration, predominant signals in the mass spectrum are the (CO2)n+ cluster ions. The unprotonated cluster ion series (CO2)nH2O+ and (CO2)n(H2O)2+ are also observed under these conditions. At low CO2 concentration, protonated cluster ions (H2O)nH+ are the dominant signals, and the protonated CO2(H2O)nH+ and unprotonated (H2O)n+ and (CO2) × (H2O)n+ cluster ion series are also observed. The mechanisms and dynamics of the formation of these neutral and ionic clusters are discussed

Stabilities of nanohydrated thymine radical cations: insights from multiphoton ionization experiments and ab initio calculations

Multi-photon ionization experiments have been carried out on thymine-water clusters in the gas phase. Metastable H2O loss from T+(H2O)n was observed at n ≥ 3 only. Ab initio quantum-chemical calculations of a large range of optimized T+(H2O)n conformers have been performed up to n = 4, enabling binding energies of water to be derived. These decrease smoothly with n, consistent with the general trend of increasing metastable H2O loss in the experimental data. The lowest-energy conformers of T+(H2O)3 and T+(H2O)4 feature intermolecular bonding via charge-dipole interactions, in contrast with the purely hydrogen-bonded neutrals. We found no evidence for a closed hydration shell at n = 4, also contrasting with studies of neutral clusters

Understanding the UK hospital supply chain in an era of patient choice

Author Posting © Westburn Publishers Ltd, 2011. This is a post-peer-review, pre-copy-edit version of an article which has been published in its definitive form in the Journal of Marketing Management, and has been posted by permission of Westburn Publishers Ltd for personal use, not for redistribution. The article was published in Journal of Marketing Management, 27(3-4), 401 - 423, doi:10.1080/0267257X.2011.547084 http://dx.doi.org/10.1080/0267257X.2011.547084The purpose of this paper is to investigate the UK hospital supply chain in light of recent government policy reform where patients will have, inter alia, greater choice of hospital for elective surgery. Subsequently, the hospital system should become far more competitive with supply chains having to react to these changes as patient demand becomes less predictable. Using a qualitative case study methodology, hospital managers are interviewed on a range of issues. Views on the development of the hospital supply chain in different phases are derived, and are used to develop a map of the current hospital chain. The findings show hospital managers anticipating some significant changes to the hospital supply chain and its workings as Patient Choice expands. The research also maps the various aspects of the hospital supply chain as it moves through different operational phases and highlights underlying challenges and complexities. The hospital supply chain, as discussed and mapped in this research, is original work given there are no examples in the literature that provide holistic representations of hospital activity. At the end, specific recommendations are provided that will be of interest to service to managers, researchers, and policymakers

Macroscopic quantum resonators (MAQRO)

Quantum physics challenges our understanding of the nature of physical reality and of space-time and suggests the necessity of radical revisions of their underlying concepts. Experimental tests of quantum phenomena involving massive macroscopic objects would provide novel insights into these fundamental questions. Making use of the unique environment provided by space, MAQRO aims at investigating this largely unexplored realm of macroscopic quantum physics. MAQRO has originally been proposed as a medium-sized fundamental-science space mission for the 2010 call of Cosmic Vision. MAQRO unites two experiments: DECIDE (DECoherence In Double-Slit Experiments) and CASE (Comparative Acceleration Sensing Experiment). The main scientific objective of MAQRO, which is addressed by the experiment DECIDE, is to test the predictions of quantum theory for quantum superpositions of macroscopic objects containing more than 10e8 atoms. Under these conditions, deviations due to various suggested alternative models to quantum theory would become visible. These models have been suggested to harmonize the paradoxical quantum phenomena both with the classical macroscopic world and with our notion of Minkowski space-time. The second scientific objective of MAQRO, which is addressed by the experiment CASE, is to demonstrate the performance of a novel type of inertial sensor based on optically trapped microspheres. CASE is a technology demonstrator that shows how the modular design of DECIDE allows to easily incorporate it with other missions that have compatible requirements in terms of spacecraft and orbit. CASE can, at the same time, serve as a test bench for the weak equivalence principle, i.e., the universality of free fall with test-masses differing in their mass by 7 orders of magnitude.Comment: Proposal for a medium-sized space mission, 28 pages, 9 figures - in v2, we corrected some minor mistakes and replaced fig. 9 with a higher-resolution version; Experimental Astronomy, March 2012, Online, Open Acces

Demonstration of a desk-top size high repetition rate soft x-ray laser

Includes bibliographical references (pages 4050-4051).We have demonstrated a new type of high repetition rate 46.9 nm capillary discharge laser that fits on top of a small desk and that it does not require a Marx generator for its excitation. The relatively low voltage required for its operation allows a reduction of nearly one order of magnitude in the size of the pulsed power unit relative to previous capillary discharge lasers. Laser pulses with an energy of ~ 13 μJ are generated at repetition rates up to 12 Hz. About (2-3) × 104 laser shots can be generated with a single capillary. This new type of portable laser is an easily accessible source of intense short wavelength laser light for applications

Dynamics and fragmentation of van der Waals clusters: (H2O)n, (CH3OH)n, and (NH3)n upon ionization by a 26.5 eV soft x-ray laser

Includes bibliographical references (pages 224319-17).A tabletop soft x-ray laser is applied for the first time as a high energy photon source for chemical dynamics experiments in the study of water, methanol, and ammonia clusters through time of flight mass spectroscopy. The 26.5 eV/photon laser (pulse time duration of ~1 ns) is employed as a single photon ionization source for the detection of these clusters. Only a small fraction of the photon energy is deposited in the cluster for metastable dissociation of cluster ions, and most of it is removed by the ejected electron. Protonated water, methanol, and ammonia clusters dominate the cluster mass spectra. Unprotonated ammonia clusters are observed in the protonated cluster ion size range 2⩽n⩽22. The unimolecular dissociation rate constants for reactions involving loss of one neutral molecule are calculated to be (0.6-2.7) × 104, (3.6-6.0) × 103, and (0.8-2.0) × 104 s−1 for the protonated water (9⩽n⩽24), methanol (5⩽n⩽10), and ammonia (5⩽n⩽18) clusters, respectively. The temperatures of the neutral clusters are estimated to be between 40 and 200 K for water clusters (10⩽n⩽21), and 50-100 K for methanol clusters (6⩽n⩽10). Products with losses of up to five H atoms are observed in the mass spectrum of the neutral ammonia dimer. Large ammonia clusters (NH3)n (n>3) do not lose more than three H atoms in the photoionization/photodissociation process. For all three cluster systems studied, single photon ionization with a 26.5 eV photon yields near threshold ionization. The temperature of these three cluster systems increases with increasing cluster size over the above-indicated ranges

Single photon ionization of hydrogen bonded clusters with a soft x-ray laser: (HCOOH)x and (HCOOH)y(H2O)z

Includes bibliographical references (pages 244301-10-244301-11).Pure, neutral formic acid (HCOOH)n+1 clusters and mixed (HCOOH)/(H2O) clusters are investigated employing time of flight mass spectroscopy and single photon ionization at 26.5 eV using a very compact, capillary discharge, soft x-ray laser. During the ionization process, neutral clusters suffer little fragmentation because almost all excess energy above the vertical ionization energy is taken away by the photoelectron, leaving only a small part of the photon energy deposited into the (HCOOH)+n+1 cluster. The vertical ionization energy minus the adiabatic ionization energy is enough excess energy in the clusters to surmount the proton transfer energy barrier and induce the reaction (HCOOH)+n+1 →(HCOOH)nH++HCOO making the protonated (HCOOH)nH+ series dominant in all data obtained. The distribution of pure (HCOOH)nH+ clusters is dependent on experimental conditions. Under certain conditions, a magic number is found at n=5. Metastable dissociation rate constants of (HCOOH)nH+ are measured in the range (0.1-0.8) × 104 s−1 for cluster sizes 4<n<9. The rate constants display an odd/even alternating behavior between monomer and dimer loss that can be attributed to the structure of the cluster. When small amounts of water are added to the formic acid, the predominant signals in the mass spectrum are still (HCOOH)nH+ cluster ions. Also observed are the protonated mixed cluster series (HCOOH)n(H2O)mH+ for n=1-8 and m=0-4. A magic number in the cluster series n=5, m=1 is observed. The mechanisms and dynamics of formation of these neutral and ionic clusters are discussed

Single photon ionization of van der Waals clusters with a soft x-ray laser: (SO2)n and (SO2)n(H2O)m

Includes bibliographical references (pages 154317-8-154317-9).van der Waals cluster (SO2)n is investigated by using single photon ionization of a 26.5 eV soft x-ray laser. During the ionization process, neutral clusters suffer a small fragmentation because almost all energy is taken away by the photoelectron and a small part of the photon energy is deposited into the (SO2)n cluster. The distribution of (SO2)n clusters decreases roughly exponentially with increasing cluster size. The photoionization dissociation fraction of I[(SO2)n−1SO+]/I[(SO2)n+] decreases with increasing cluster size due to the formation of cluster. The metastable dissociation rate constants of (SO2)n+ are measured in the range of (0.6-1.5) × 104 s−1 for cluster sizes 5⩽n⩽16. Mixed SO2-H2O clusters are studied at different experimental conditions. At the condition of high SO2 concentration (20% SO2 partial pressure), (SO2)n+ cluster ions dominate the mass spectrum, and the unprotonated mixed cluster ions (SO2)nH2O+ (1⩽n⩽5) are observed. At the condition of low SO2 concentration (5% SO2 partial pressure) (H2O)nH+ cluster ions are the dominant signals, and protonated cluster ions (SO2)(H2O)nH+ are observed. The mixed clusters, containing only one SO2 or H2O molecule, SO2(H2O)nH+ and (SO2)nH2O+ are observed, respectively

Eyeball tattoos. A new extreme trend in body modification

Einführung Augapfeltätowierungen („eyeball tattoos“, syn. episklerale Tätowierungen) sind ein neuer Trend extremer „body modification“, bei dem mit einer Nadel Tätowierfarbe unter die Bindehaut injiziert wird und zu einer irreversiblen Färbung der Sklera führt. In der medizinischen Fachliteratur werden vermehrt Fallberichte vorgestellt, bei denen teils schwerwiegende Komplikationen aufgetreten sind. Material und Methoden Neben einer aktuellen Literaturreche zum Thema wurde eine Anfrage an 120 zufällig ausgewählte Tattoo-Studios in 6 europäischen Ländern gerichtet, ob sie Eyeball-Tätowierungen anbieten. Die Kommunikation wurde bei den Studios, die diese Frage positiv beantworteten, gezielt vertieft. Ziel war es, einen Eindruck zu Angebot und Nachfrage, der Aufklärung über Risiken, Häufigkeit und Art beobachteter Komplikationen, den Vorerfahrungen und ggf. zur medizinischen Ausbildung der Tätowierenden sowie zum organisatorischen und zum technischen Ablauf der eigentlichen Prozedur der episkleralen Tätowierung im jeweiligen Studio zu gewinnen. Auf Tattoo Conventions und über Foren in sozialen Medien wurden 6 Personen mit max. 7 Jahre alten Eyeball tattoos ausführlich zu ihren Erfahrungen vor, während und nach der Augapfeltätowierung befragt. Resultate Neun Studios teilten mit, Augapfeltätowierungen anzubieten bzw. durch Gasttätowierer organisieren zu können. Die restlichen 49 Studios lehnten diese Prozedur ab. Insgesamt 4 Studios schätzten die Häufigkeit der Prozedur auf 10- bis 20-mal/Jahr; die restlichen Studios gaben an, lediglich sporadische Anfragen zu erhalten. Durch ein Studio wurde der Fall einer schweren Komplikation in Form einer persistierenden anhaltenden Infektion mit initial reduziertem, später gebessertem Visus berichtet. Ein Tätowierer gab an, in ca. jedem 20. Fall Pigmentwanderungen in die periorbitalen Gewebe zu beobachten. Postprozedural wurden bis zu 2 Wochen andauernde Kopfschmerzen, anhaltendes Fremdkörpergefühl und Lichtempfindlichkeit beschrieben. Keine der interviewten Personen mit Eyeball tattoos habe eine bleibende Visusminderung bemerkt, eine beklagte Lichtscheu, eine weitere negative soziale Folgen. Ablehnungserfahrungen seien jedoch seltener als Zuspruch. Schlussfolgerung Episklerale Tätowierungen sind noch selten, nehmen aber stetig zu. Sie werden von Personen durchgeführt, die keine hinreichende medizinische Ausbildung besitzen und eintretende Komplikationen nicht ausreichend einschätzen können. Die im Interview berichtete Seltenheit schwerwiegender Komplikationen kontrastiert mit der Darstellung desaströser Folgen in den sozialen Medien, deren breite Präsenz jedoch auf redundanten Darstellungen einzelner Fälle beruhen kann. Andererseits sind die Angaben der Befürworter zu hinterfragen, weil sie womöglich aus geschäftlichen Überlegungen heraus oder aus Angst vor rechtlichen Konsequenzen Problemfälle unterschlagen oder deren Verläufe beschönigen. Die Diskussion, ob solche risikoreichen irreversiblen Body modifications verboten werden sollten, muss von anderer Stelle geführt werden.Introduction Eyeball tattoos (aka episcleral tattooing) are a new trend of extreme body modification, in which tattoo ink is injected under the conjunctiva with a needle and leads to an irreversible coloring of the sclera. Increasing numbers of case reports are presented in the medical literature, where in some cases severe complications have occurred. Material and method In addition to a current literature search on the topic, a query was sent out to 120 randomly selected tattoo studios in 6 European countries asking if they carry out eyeball tattooing. The communication was examined in more detail for those studios that answered this question positively. The aim was to obtain an impression of the supply and demand, the clarification of the risks, frequency and type of complications observed, the previous experience and possibly medical training of the tattooist. They were also questioned on the organizational and technical aspects of the actual procedure of episcleral tattooing in each studio. At tattoo conventions and via forums in social media 6 persons with a maximum of 7‑year-old eyeball tattoos were extensively questioned about their experiences before, during and after the eyeball tattooing. Results Of the studios nine replied that they could provide eyeball tattooing or that they could organize a guest tattooist. The remaining 49 studios did not carry out this procedure. A total of 4 studios estimated the frequency of the procedure to be 10–20 times per year and the remaining studios had only received sporadic enquiries. Of the studios one reported a case of a severe complication in the form of a persisting continuous infection with initially reduced but later improved visual acuity. Of the tattooists 1 stated that pigment migration into the periorbital tissue was observed in approximately 1 in 20 cases. Persisting headache, continuous foreign body sensation and sensitivity to light were described up to 2 weeks after the procedure. None of the persons with eyeball tattoos interviewed had noticed a residual reduction of vision, one complained of photophobia and another of negative social consequences; however, experiences of rejection were less common than appreciation. Conclusion Episcleral tattoos are still rare but are steadily increasing. They are carried out by persons without adequate medical training who cannot sufficiently assess complications when they occur. The rarity of severe complications reported in the interviews is in contradiction to the presentation of disastrous sequelae in the social media; however, their broad presence can be based on redundant presentations of individual cases. Alternatively, the statements of the proponents could be considered questionable, as they possibly withhold problem cases or whitewash the sequelae because of commercial considerations or for fear of legal consequences. The discussion on whether such high-risk irreversible body modifications should be banned, is outside the competence of this study