bluuebunny/crossref_metadata_2025 huggingface dataset:
The future of lasers
Authors: Bloembergen Nicolaas , Prokhorov Alexandr M. , Porto Sergio P. , Townes Charles H. , Javan Ali , Stoicheff Boris P. , Jacquinot Pierre , Kidder Raymond E. , Schawlow Arthur L.
Published: December 2008

At the Esfahan Symposium on Fundamental and Applied Laser Physics, which took place 29 August–5 September 1971, the world's laser specialists gathered to exchange notes on the state of the field and its probable future. The symposium was held on the campus of Esfahan University in Esfahan, the second largest city of Iran, under the auspices of Arya-Mehr University of Technology and with the support and cooperation of Esfahan University and the Massachusetts Institute of Technology. Ali Javan (MIT) was director of the symposium, which was sponsored by the International Union of Pure and Applied Physics.
The concept of the photon
Authors: Scully Marlan O. , Sargent Murray
Published: December 2008

The idea of the photon has stirred the imaginations of physicists ever since 1905 when Einstein originally proposed the use of light quanta to explain the photoelectric effect. This concept is formalized in the quantum theory of radiation, which has had unfailing success in explaining the interaction of electromagnetic radiation with matter, seemingly limited only by the ability of physicists to perform the indicated calculations. Nevertheless, it has its conceptual problems—various infinities and frequent misinterpretations. Consequently an increasing number of workers are asking, “to what extent is the quantized field really necessary and useful?” In fact the experimental results of the photoelectric effect were explained by G. Wentzel in 1927 without the quantum theory of radiation. Similarly most electro-optic phenomena such as stimulated emission, reaction of the emitted field on the emitting atom, resonance fluorescence, and so on, do not require the quantization of the field for their explanation. As we will see, these processes can all be quantitatively explained and physically understood in terms of the semiclassical theory of the matter–field interaction in which the electric field is treated classically while the atoms obey the laws of quantum mechanics. The quantized field is fundamentally required for accurate descriptions of certain processes involving fluctuations in the electromagnetic field: for example, spontaneous emission, the Lamb shift, the anomalous magnetic moment of the electron, and certain aspects of blackbody radiation. (The Compton effect also fits here, but see later under references 8b and c.) Here we will outline how the photon concept originated and developed, where it is not required and is often misused, and finally where it plays an essential role in the understanding of physical phenomena. In our discussion we will attempt to give a logically consistent definition of the word “photon”—a statement far more necessary than one might think, for so many contradictory uses exist of this elusive beast. In particular consider the original coining of the word by G. N. Lewis:

“[because it appears to spend] only a minute fraction of its existence as a carrier of radiant energy, while the rest of the time it remains an important structural element within the atom…, I therefore take the liberty of proposing for this hypothetical new atom which is not light but plays an essential part in every process of radiation, the name photon!”

(our exclamation point). Clearly the present usage of the word is very different.
Absolute laser frequency measurements
Authors: Rothenberg Marian S.
Published: December 2008

If we knew a precise value for the frequency of the length standard, or, alternatively, for the wavelength of the frequency standard, we would have a good way to define the velocity of light c. But until now the hitch has been that wavelength measurements, although fairly easily done in the visible through the near infrared (to three microns or so), are difficult at longer wavelengths, whereas frequency measurements have until recently been limited to the microwave region. Now a group at the National Bureau of Standards in Boulder, Colorado, mixing their oscillators by means of a metal–metal diode originally used at the Massachusetts Institute of Technology, reports the highest “absolute” frequency measurement to date.
New class of high-temperature superconductors
Authors: Lubkin Gloria B.
Published: December 2008

In the search for high-temperature superconductors the path led from individual elements to binary compounds, to pseudobinary compounds, and eventually to ternary compounds. At first at least one of the elements in the binary compound was superconducting. Eventually hundreds of binary compounds were found in which neither of the elements was superconducting above 1 K.
Batavia accelerator reaches 200 GeV
Authors: Lubkin Gloria B.
Published: December 2008

Now that the Batavia accelerator has reached its design energy of 200 GeV (on 1 March), physicists can breathe a sigh of relief, although considerable effort remains to be expended before the machine operates at full intensity. Director Robert R. Wilson had hoped to bring the accelerator into operation a year early, in mid-1971 (PHYSICS TODAY, June 1970, page 29) and soon after to raise the energy to 500 GeV at reduced intensity.
Noise thermometers in millidegree range
Authors: Lubkin Gloria B.
Published: December 2008

John Wheatley is known for his work at very low temperatures. When we recently visited his laboratory deep underground in Urey Hall at the University of California in La Jolla, Wheatley told us that he is excited about a noise thermometer that has its instrumental noise limit in the microdegree region. In work with Richard Webb and Robin Gifford this thermometer has measured 5 millideg K.
1932—Moving into the new physics
Authors: Weiner Charles
Published: December 2008

In 1972 we celebrate the fortieth anniversary of the “annus mirabilis” of nuclear and particle physics. Seen from the perspective of the present, the cluster of major conceptual and technical developments of 1932 mark that “marvelous” year as a very special one. It began with Harold Urey's announcement in January that he had discovered a heavy isotope of hydrogen, which he called “deuterium.” In February James Chadwick demonstrated the existence of a new nuclear constituent, the neutron. In April John Cockcroft and E. T. S. Walton achieved the first disintegration of nuclei by bombarding light elements with artificially accelerated protons. In August Carl Anderson's photographs of cosmic-ray tracks revealed the existence of another new particle, the positively charged electron, soon to be called the “positron.” And later that summer Ernest Lawrence, Stanley Livingston and Milton White disintegrated nuclei with the cyclotron, an instrument that would generate almost 5-million electron volts by the end of that eventful year.
Physical world of the child
Authors: Piaget Jean
Published: December 2008

A child's view of physics is not as “childish” as we might think. On the contrary, it raises a series of problems that might interest an historian of science or even a physicist who, comparing the present state of physics with earlier stages of development, asks why certain ideas have been better able than others to resist the upheavals that have occurred in physics since the turn of the century. In our studies of children we have observed them playing with simple toys, questioned them about their perceptions and posed problems for them to solve. From these studies, we have learned something of the way a child's mind develops mathematical and physical concepts—such as topology, speed, time and causality—as well as something of the nature of the ideas themselves.
Physics for beginners
Authors: Karplus Robert
Published: December 2008

Take a spring, stretch it an inch or two, and imagine the force exerted by it. You will have no difficulty with this problem, and a layman or child will have no difficulty either, especially if you use the term “pull” instead of “force” in your question. Now take a second similar spring, hook it to the first one, and stretch the combination until each spring is extended to the same distance as the single spring before. When you then ask about the pull, most nonphysicists will state that it is obviously twice what it was before, because there are two springs instead of one. Try to convince them that the force has the same magnitude as before, because each spring is stretched by the same amount! How would you proceed?
AEC opens up on laser fusion implosion concept
Authors: Lubkin Gloria B.
Published: December 2008

Interest in laser-produced thermonuclear fusion is increasing rapidly. Until recently almost all discussion in the open literature mentioned only the possibility of using the laser to heat a fusion-fuel pellet, and most observers argued that the laser energy requirement for a fusion reactor would be impracticably high.
Diffusion pumps
Authors: Levi Barbara G.
Published: December 2008

Over the past ten or fifteen years, modifications of the diffusion pump have doubled its pumping speed reduced backstreaming of pump fluids by four or five orders of magnitude. These improvements result from redesign of some basic pump features and from development of new pump fluids with lower vapor pressures.
Gauges for ultrahigh vacuum
Authors: Lange W. J.
Published: December 2008

The basis for essentially all gauges used for total or partial-pressure measurement in ultrahigh vacuum is the ionization produced by electrons traversing the space between two electrodes. The ratio of ion current to ionizing current is measured and assumed to be proportional to the gas density or pressure. This principle has been used for over fifty years, spurred and nurtured by the vacuum-tube industry, so it was natural that early gauges resembled simple triode receiving tubes (see figure 1 on the facing page).
SLAC runs one storage ring, plans one
Authors: Lubkin Gloria B.
Published: December 2008

The electron–positron storage ring, SPEAR, is now running at SLAC as scheduled, and performance attained so far meets all expectations. Now SLAC, in collaboration with the Lawrence Berkeley Laboratory (LBL), is looking ahead to a still more powerful colliding-beam device called “PEP”, a device that would involve collisions between protons, electrons and positrons.
IUPAP–Past and future
Authors: Bacher Robert F. , Havens William W. , Koch H. William , Marshak Robert E. , Seitz Frederick
Published: December 2008

Although “everyone” has heard of IUPAP, many of us are unaware of what it is (a membership organization? an organization of other organizations?), what it does, and how it is financed (does the money come out of our American Physical Society or Optical Society dues? out of our taxes?).
Plutonium result supports theory of shape isomers
Authors: Lubkin Gloria B.
Published: December 2008

Over the past few years evidence has grown for the existence of a double-humped fission barrier in many different nuclei. These nuclei when caught between the two humps would then exist in isomeric states with lifetimes that were very long considering their excitation. The phenomenon goes by the name of “shape isomerism.” Now a Munich group has reported (at the European Conference on Nuclear Physics in Aix en Provence, at the end of June) that they have found a rotational band associated with the second minimum in the fission barrier, thus providing strong support for the idea of shape isomerism. The group consists of Hans J. Specht and J. Weber of the University of Munich and E. Konecny and D. Heunemann of the Munich Technical University.
X-ray laser formed from a gelatine–CuSO4 sandwich?
Authors: Lubkin Gloria B.
Published: December 2008

A group at the University of Utah believes they have made a hard x-ray laser. The strikingly simple experiment was reported by John G. Kepros in a post-deadline paper at the Third Rochester Conference on Coherence and Quantum Optics at the end of June. Subsequently Edward M. Eyring, F. William Cagle Jr and Kepros published a paper in the Proceedings of the National Academy of Sciences (69, 1744, 1972).
Cave drawing is evidence of Crab nebula supernova
Authors: Hein Steven M.
Published: December 2008

What appears to be the fourth independent record of the Crab nebula supernova in 1054 was discovered in a cave in northern California, according to Stephen Maran of NASA's Goddard Space Flight Center. The American Indian petroglyph consists of a drawing of a sphere and a crescent; the sphere is thought to represent the supernova and the crescent, the moon. The findings were reported at the Michigan State Meeting of the American Astronomical Society in August.
Einstein on the firing line
Authors: Will Clifford M.
Published: December 2008

In astronomer detects mysterious pulses in the light from a star at the center of the Crab Nebula, and theorists speculate that the source is a rotating neutron star (a “pulsar”). Massive aluminum cylinders in Illinois and Maryland are suddenly and simultaneously set into vibration, and theorists suggest that a gravitational wave has just passed through the solar system. Radio astronomers discover that space is filled with blackbody radiation at a temperature of about 3 K, and theorists say that it is a by-product of the initial “big bang” of the Universe. X-ray astronomers discover aperiodic fluctuations in the x-ray emission from Cygnus-X1; optical astronomers discovered that Cygnus-X1 is associated with a single-line spectroscopic binary star: from this evidence theorists speculate that the x rays come from a black hole orbit around a normal star.
Clouds and precipitation
Authors: Sartor J. Doyne
Published: December 2008

In these days of emphasis on environmental problems, studies of clouds and precipitation take on an added importance. Clouds and precipitation cleanse the atmosphere of natural and manmade pollutants or process them for later removal. Cloud radiative and dynamic properties control a good deal more than half of the solar energy available for keeping the atmosphere moving, and precipitation keeps the continents green (or white). Destructive storms are spawned mostly from cloud systems, but Man can modify his local environment to some extent now through the “seeding” of clouds, and possibly he will eventually be able to control severe storms and remove damaging pollutants.
Ultraviolet and x-ray observatory in orbit
Authors: Hein Steven M.
Published: December 2008

Copernicus, the most recent of NASA's Orbiting Astronomical Observatories, has been placed in orbit and is operating successfully. The ultraviolet and x-ray telescopes it carries are both reported to be in good order, and the pointing system that aims them for observation is operating at better than expected accuracy.
Thermodynamics of evolution
Authors: Prigogine Ilya , Nicolis Gregoire , Babloyantz Agnes
Published: December 2008

The physicochemical basis of biological order is a puzzling problem that has occupied whole generations of biologists and physicists and has given rise, in the it, to passionate discussions. Biological systems are highly complex and ordered objects. It is generally accepted that the present order reflects structures acquired during a long evolution. Moreover, the maintenance of order in actual living systems requires a great number of metabolic and synthetic reactions as well as the existence of complex mechanisms controlling the rate and the timing of the various processes. All these features bring the scientist a wealth of new problems. In the first place one has systems that have evolved spontaneously to extremely organized and complex forms. On the other hand metabolism, synthesis and regulation imply a highly heterogeneous distribution of matter inside the cell through chemical reactions and active transport. Coherent behavior is really the characteristic feature of biological systems (see the box on page 24).
Josephson-junction method detects nmr transitions
Authors: Scott John T.
Published: December 2008

In nuclear-magnetic-resonance work, the detection of broad lines such as those from solid samples has usually been done by observing a pulse in a radiofrequency pickup coil while carrying out a procedure known as “adiabatic fast passage.” A new technique, in which detection during adiabatic fast passage is by a Josephson-junction magnetometer, does the same job but with considerably less radiofrequency power.
Physics in China
Authors: Lubkin Gloria B.
Published: December 2008

The People's Republic of China has made remarkable progress in many aspects of applied physics. This was the conclusion drawn by seven physicists from the United States who recently visited China and then discussed their observations with us. They saw the production of integrated circuits, controlled-fusion experiments, a superconducting gravimeter, telescopes, a variety of scientific instruments—all produced in China. The US visitors generally got the impression that China was concentrating very much on applications, rather than basic research. And they found a society-wide attempt to make the higher-education system more democratic.
Thermodynamics of evolution
Authors: Prigogine Llya , Nicolis Gregoire , Babloyantz Agnes
Published: December 2008

We have seen that the formation and maintenance of self-organizing systems are compatible with the laws of physical chemistry. We must now confront this idea with the major problem of biology: How did biological systems arise?
Expression levels of a filament-specific transcriptional regulator are sufficient to determine
Candida albicans
morphology and virulence
Authors: Carlisle Patricia L. , Banerjee Mohua , Lazzell Anna , Monteagudo Carlos , López-Ribot José L. , Kadosh David
Published: December 2008

Candida albicans
, the major human fungal pathogen, undergoes a reversible morphological transition from single yeast cells to pseudohyphal and hyphal filaments (elongated cells attached end-to-end). Because typical
C. albicans
infections contain a mixture of these morphologies it has, for many years, been difficult to assess the relative contribution of each form to virulence. In addition, the regulatory mechanisms that determine growth in pseudohyphal and hyphal morphologies are largely unknown. To address these questions we have generated a
C. albicans
strain that can be genetically manipulated to grow completely in the hyphal form under non-filament-inducing conditions in vitro. This was achieved by inducing high-level constitutive expression of
UME6
, a recently identified filament-specific transcriptional regulator of
C. albicans
hyphal extension. We show that high-level
UME6
expression significantly increases hyphal formation and promotes virulence in a mouse model of systemic candidiasis. Our results strongly suggest that shifting the morphology of a
C. albicans
population toward the hyphal form, and/or increasing hyphal-specific gene expression, during the course of infection is sufficient to improve virulence potential. We also demonstrate that lower levels of
UME6
expression specify growth largely in the pseudohyphal form and that increasing
UME6
levels is sufficient to cause cells to gradually shift from pseudohyphal to hyphal morphology. In addition, we show that
UME6
levels differentially induce the expression of several known filament-specific transcripts. These findings suggest that a common transcriptional regulatory mechanism functions to specify both pseudohyphal and hyphal morphologies in a dosage-dependent manner.
Synaptic activity-responsive element in the
Arc
/
Arg3.1
promoter essential for synapse-to-nucleus signaling in activated neurons
Authors: Kawashima Takashi , Okuno Hiroyuki , Nonaka Mio , Adachi-Morishima Aki , Kyo Nan , Okamura Michiko , Takemoto-Kimura Sayaka , Worley Paul F. , Bito Haruhiko
Published: December 2008

The neuronal immediate early gene
Arc
/
Arg-3.1
is widely used as one of the most reliable molecular markers for intense synaptic activity in vivo. However, the
cis
-acting elements responsible for such stringent activity dependence have not been firmly identified. Here we combined luciferase reporter assays in cultured cortical neurons and comparative genome mapping to identify the critical synaptic activity-responsive elements (SARE) of the
Arc
/
Arg-3.1
gene. A major SARE was found as a unique ≈100-bp element located at >5 kb upstream of the
Arc
/
Arg-3.1
transcription initiation site in the mouse genome. This single element, when positioned immediately upstream of a minimal promoter, was necessary and sufficient to replicate crucial properties of endogenous
Arc
/
Arg-3.1'
s transcriptional regulation, including rapid onset of transcription triggered by synaptic activity and low basal expression during synaptic inactivity. We identified the major determinants of SARE as a unique cluster of neuronal activity-dependent
cis
-regulatory elements consisting of closely localized binding sites for CREB, MEF2, and SRF. Consistently, a SARE reporter could readily trace and mark an ensemble of cells that have experienced intense activity in the recent past in vivo. Taken together, our work uncovers a novel transcriptional mechanism by which a critical 100-bp element, SARE, mediates a predominant component of the synapse-to-nucleus signaling in ensembles of Arc/Arg-3.1-positive activated neurons.
The use of amphipols as universal molecular adapters to immobilize membrane proteins onto solid supports
Authors: Charvolin Delphine , Perez Jean-Baptiste , Rouvière Florent , Giusti Fabrice , Bazzacco Paola , Abdine Alaa , Rappaport Fabrice , Martinez Karen L. , Popot Jean-Luc
Published: December 2008

Because of the importance of their physiological functions, cell membranes represent critical targets in biological research. Membrane proteins, which make up ≈1/3 of the proteome, interact with a wide range of small ligands and macromolecular partners as well as with foreign molecules such as synthetic drugs, antibodies, toxins, or surface recognition proteins of pathogenic organisms. Whether it is for the sake of basic biomedical or pharmacological research, it is of great interest to develop tools facilitating the study of these interactions. Surface-based in vitro assays are appealing because they require minimum quantities of reagents, and they are suitable for multiplexing and high-throughput screening. We introduce here a general method for immobilizing functional, unmodified integral membrane proteins onto solid supports, thanks to amphipathic polymers called “amphipols.” The key point of this approach is that functionalized amphipols can be used as universal adapters to associate any membrane protein to virtually any kind of support while stabilizing its native state. The generality and versatility of this strategy is demonstrated by using 5 different target proteins, 2 types of supports (chips and beads), 2 types of ligands (antibodies and a snake toxin), and 2 detection methods (surface plasmon resonance and fluorescence microscopy).
A reappraisal of evidence for probabilistic models of allelic exclusion
Authors: Taylor Benjamin , Cobb Bradley S. , Bruno Ludovica , Webster Zoe , Fisher Amanda G. , Merkenschlager Matthias
Published: December 2008

B cell development requires the coordinated rearrangement of Ig heavy (
IgH
) and light chain loci (
IgL
). Most mature B cells express a single B cell receptor of unique specificity, and a central question in immunology concerns the mechanisms that prevent the productive rearrangement of >1
IgH
and
IgL
allele per cell. Probabilistic models of allelic exclusion maintain that simultaneous rearrangement of both alleles is rare, because the likelihood of undergoing rearrangement is low for a given
Ig
allele. Strong support for this idea came from studies in which a GFP marker was inserted into the
Igk
locus. In this system, the probability of high-level germ-line transcription and subsequent locus rearrangement appeared to be low in pre-B cells. Readdressing the validity of GFP expression as a reporter for the level of germ-line transcription, we found a striking discordance between GFP transcript and protein levels at the pre-B cell stage, which is explained at least in part by the developmentally regulated usage of 2 alternative
Igk-J
germ-line promoters. These results question the validity of the kappa-GFP system as evidence for probabilistic models of allelic exclusion.
Genome rhetoric and the emergence of compositional bias
Authors: Vetsigian Kalin , Goldenfeld Nigel
Published: December 2008

Genomes exhibit diverse patterns of species-specific GC content, GC and AT skews, codon bias, and mutation bias. Despite intensive investigations and the rapid accumulation of sequence data, the causes of these a priori different genome biases have not been agreed on and seem multifactorial and idiosyncratic. We show that these biases can arise generically from an instability of the coevolutionary dynamics between genome composition and resource allocation for translation, transcription, and replication. Thus, we offer a unifying framework for understanding and analyzing different genome biases. We develop a test of multistability of nucleotide composition of completely sequenced genomes and reveal a bistability forBorrelia burgdorferi, a genome with pronounced replication-related biases. These results indicate that evolution generates rhetoric, it improves the efficiency of the genome's communication with the cell without modifying the message, and this leads to bias.
Changes in H5N1 influenza virus hemagglutinin receptor binding domain affect systemic spread
Authors: Yen Hui-Ling , Aldridge Jerry R. , Boon Adrianus C. M. , Ilyushina Natalia A. , Salomon Rachelle , Hulse-Post Diane J. , Marjuki Henju , Franks John , Boltz David A. , Bush Dorothy , Lipatov Aleksandr S. , Webby Richard J. , Rehg Jerold E. , Webster Robert G.
Published: December 2008

The HA of influenza virus is a receptor-binding and fusion protein that is required to initiate infection. The HA receptor-binding domain determines the species of sialyl receptors recognized by influenza viruses. Here, we demonstrate that changes in the HA receptor-binding domain alter the ability of the H5N1 virus to spread systemically in mice. The A/Vietnam/1203/04 (VN1203) and A/Hong Kong/213/03 (HK213) viruses are consistently lethal to domestic chickens but differ in their pathogenicity to mammals. Insertion of the VN1203 HA and neuraminidase (NA) genes into recombinant HK213 virus expanded its tissue tropism and increased its lethality in mice; conversely, insertion of HK213 HA and NA genes into recombinant VN1203 virus decreased its systemic spread and lethality. The VN1203 and HK213 HAs differ by 10 aa, and HK213 HA has shown greater binding affinity for synthetic α2,6-linked sialyl receptor. Introduction of an S227N change and removal of
N
-linked glycosylation at residue 158 increased the α2,6-binding affinity of VN1203 HA. Recombinant VN1203 virus carrying the S227N change alone or with the residue-158 glycosylation site removed showed reduced lethality and systemic spread in mice but not in domestic chickens. Wild-type VN1203 virus exhibited the greatest efficiency in systemic spread after intramuscular inoculation and in infection of mouse bone marrow-derived dendritic cells and conventional pulmonary dendritic cells. These results show that VN1203 HA glycoprotein confers pathogenicity by facilitating systemic spread in mice; they also suggest that a minor change in receptor binding domain may modulate the virulence of H5N1 viruses.
Does Smoking Intervention Influence Adolescent Substance Use Disorder Treatment Outcomes?
Authors: Myers Mark G. , Prochaska Judith J.
Published: December 2008

Although tobacco use is reported by the majority of substance use disordered (SUD) youth, little work has examined tobacco focused interventions with this population. The present study is an initial investigation of the effect of a tobacco use intervention on adolescent SUD treatment outcomes. Participants were adolescents in SUD treatment taking part in a cigarette smoking intervention efficacy study, assessed at baseline and followed up at 3- and 6-months post-intervention. Analyses compared treatment and control groups on days using alcohol and drugs and proportion abstinent from substance use at follow up assessments. Adolescents in the treatment condition reported significantly fewer days of substance use and were somewhat more likely to be abstinent at 3-month follow up. These findings suggest that tobacco focused intervention may enhance SUD treatment outcome. The present study provides further evidence for the value of addressing tobacco use in the context of treatment for adolescent SUD's.
Follow-Up Study of Crack Cocaine Users: Situation of the Patients after 2, 5, and 12 Years
Authors: Dias Andréa Costa , Ribeiro Marcelo , Dunn John , Sesso Ricardo , Laranjeira Ronaldo
Published: December 2008

The purpose of this study was to follow-up 131 crack users and examine drug use, treatment experience, employment status, and mortality at 2, 5, and 12 years. Consecutive crack dependent patients were re-interviewed in 1995–1996, 1998–1999, and 2005–2006. Of those subjects not using cocaine at 2 years, 19 (63%) were still abstinent at 5 years. Almost half of the users were abstinent at the same period. The abstinent group was still the most prevalent at 12 years. Twenty-seven (20.6%) patients had died by the 12-year follow-up, with homicide being the most common cause (n = 16). After 2000, however, it declined sharply with only 2 deaths in 7 years. There was a progressive movement toward abstinence over the follow-up period, with the evidence that once abstinence had been achieved it was maintained. On the other hand, the mortality rate was extremely high and probably more related with socioeconomic factors instead of the drug use itself.
Pharmacotherapy of Methamphetamine Addiction: An Update
Authors: Elkashef Ahmed , Vocci Frank , Hanson Glen , White Jason , Wickes Wendy , Tiihonen Jari
Published: December 2008

Methamphetamine dependence is a serious public health problem worldwide for which there are no approved pharmacological treatments. Psychotherapy is still the mainstay of treatment; however, relapse rates are high. The search for effective pharmacological treatment has intensified in the last decade. This review will highlight progress in pharmacological interventions to treat methamphetamine dependence as well as explore new pharmacological targets. Published data from clinical trials for stimulant addiction were searched using PubMed and summarized, as well as highlights from a recent symposium on methamphetamine pharmacotherapy presented at the ISAM 2006 meeting, including interim analysis data from an ongoing D-amphetamine study in Australia. Early pilot data are encouraging for administering D-amphetamine and methylphenidate as treatment for heavy amphetamine users. Abilify at 15 mg/day dose increased amphetamine use in an outpatient pilot study. Sertraline, ondansetron, baclofen, tyrosine, and imipramine were ineffective in proof-of-concept studies. Development of pharmacotherapy for methamphetamine dependence is still in an early stage. Data suggesting D-amphetamine and methylphenidate as effective pharmacotherapy for methamphetamine addiction will need to be confirmed by larger trials. Preclinical data suggest that use of GVG, CB1 antagonist, and lobeline are also promising therapeutic strategies.
Comorbid Psychiatric and Substance Abuse Disorders: Recent Treatment Research
Authors: Riggs Paula , Levin Frances , Green Alan I. , Vocci Frank
Published: December 2008

Psychiatric comorbidity is defined as the co-occurrence of a psychiatric disorder in a patient with a substance use disorder. Psychiatric disorders in substance abuse patients can antedate the substance use disorder or be a consequence of the substance abuse. There is emerging evidence that drug use in adolescence may alter the onset of certain psychiatric disorders in vulnerable individuals. Patients with concurrent comorbid disorders present special challenges for the substance abuse treatment system in terms of diagnosis and management because each disorder has the capability of exacerbating the other.

This manuscript is a summary of an ISAM symposium that featured three speakers who discussed the following topics: 1. Etiology and treatment of comorbid psychiatric and substance use disorders in adolescents; 2. Treatment of ADHD and substance use disorders in adults; 3. Effects of substance abuse on the onset, severity, and treatment of schizophrenia.

Recommendations for further research will be presented.
Alcohol Use Disorders among Afghan Migrants in Germany
Authors: Haasen Christian , Sinaa Mirweys , Reimer Jens
Published: December 2008

Little is known about the effect of acculturation on patterns of alcohol use for migrants from Islamic countries. In a field study of Afghan migrants to Germany, participants who drink alcohol were screened with respect to alcohol use problems and then interviewed concerning patterns of use, mental health, and sociodemographic variables. Snowball sampling was used until 50 Afghan migrants with alcohol use disorders could be interviewed. A significant correlation was found between acculturation stress and mental distress, as well as between mental distress and severity of alcohol use. These correlations did not differ with respect to whether alcohol had been used prior to migration. The findings support the hypothesis of the effect of acculturation on problematic alcohol use. Acculturation needs to be focused on in the treatment of alcohol use disorders.
Drug Exposure Opportunities and Use Patterns among College Students: Results of a Longitudinal Prospective Cohort Study
Authors: Arria Amelia M. , Caldeira Kimberly M. , O'Grady Kevin E. , Vincent Kathryn B. , Fitzelle Dawn B. , Johnson Erin P. , Wish Eric D.
Published: December 2008

Underage drinking and drug use among college students are major public health concerns, yet few studies have examined these behaviors and their associated risk factors and consequences prospectively. This paper describes the sampling and recruitment methods of a longitudinal study of 1253 college students at a large, mid-Atlantic university. Incoming first-year students were screened during the unique window between high school and college in order to oversample drug users for longitudinal follow-up. Intensive recruitment strategies yielded a 95% cumulative response rate in annual interviews and semiannual surveys. The authors report preliminary results on exposure opportunity, lifetime prevalence, initiation, continuation, and cessation of substance use for alcohol, tobacco, and 10 illicit and prescription drugs during the first 2 years of college. Findings suggest that although some substance use represents a continuation of patterns initiated in high school, exposure opportunity and initiation of substance use frequently occur in college. Implications for prevention and early intervention are discussed.
Development of the Pretreatment Readiness Scale for Substance Abusers: Modification of an Existing Motivation Assessment
Authors: Rapp Richard C. , Carr Carey A. , Lane D. Tim , Redko Cristina , Carlson Robert G.
Published: December 2008

The Texas Christian University–Treatment Motivation Assessment (TCU-TMA) was originally developed to assess motivation among in-treatment opiod users. Numerous studies of in-treatment substance abusers in a variety of settings have confirmed the three factors present in the scale, including Problem Recognition, Desire For Help, and Treatment Readiness. The goal of the present study was to examine the factor structure of the TCU-TMA in a sample of 367 pretreatment substance abusers assessed at a centralized intake unit who had not yet entered treatment. Exploratory and confirmatory factor analyses led to the development of the Pretreatment Readiness Scale (PRS) that, like the TCU-TMA, contained Problem Recognition and Treatment Readiness factors. Desire for Change replaced Desire for Help in the new scale and Treatment Reluctance indicated mixed feelings about entering treatment. The implications of these findings on developing interventions for the pretreatment group will be discussed.
Factors Associated with Seeking Readmission among Clients Admitted to Medical Withdrawal Management
Authors: Li Xin , Sun Huiying , Marsh David C. , Anis Aslam H.
Published: December 2008

The objectives of the present paper were to determine the rate and factors associated with seeking readmission among the clients admitted to an inpatient medical withdrawal management program, Vancouver Detox (VD). All clients who were admitted to VD between July 1, 2003, and June 30, 2004, were included in the study, and were followed up for 1 year. Multinomial logistic regression was performed to investigate the potential risk factors associated with short-term (1 month) and long-term (2 to 12 months) requests for readmission simultaneously. The risk factor associated with short-term request for readmission was leaving VD against medical advice (AMA) during the index admission. Clients who reported to have hepatitis C virus (HCV) infection, whose primary preferred substance was alcohol, and those who were poly-drug users were more likely to request readmission in long-term. Clients with no fixed address were less likely to seek readmission between months 2 and 12.
DIRECT SIMULATIONS OF PARTICLE ACCELERATION IN A FLUCTUATING ELECTROMAGNETIC FIELD ACROSS A SHOCK
Authors: Muranushi Takayuki , Inutsuka Shu-ichiro
Published: December 2008

We simulate the acceleration processes of collisionless particles in a shock structure with magnetohydrodynamical (MHD) fluctuations. The electromagnetic field is represented as a sum of MHD shock solutions (B
0, E
0) and torsional Alfvén mode spectra (δB, δE). We represent fluctuation modes in logarithmic wavenumber space. Since the electromagnetic fields are represented analytically, our simulations can easily cover as large as eight orders of magnitude in resonant frequency, and do not suffer from spatial limitations of box size or grid spacing. We deterministically calculate the particle trajectories under the Lorenz force for a time interval of up to 10 years, with a time step of ∼0.5 s. This is sufficient to resolve Larmor frequencies without a stochastic treatment. Simulations show that the efficiency of the first-order Fermi acceleration can be parameterized by the fluctuation amplitude

. Convergence of the numerical results is shown by increasing the number of wave modes in Fourier space while fixing η. The efficiency of the first-order Fermi acceleration has a maximum at η ≃ 101. The acceleration rate depends on the angle between the shock normal and B
0, and is highest when the angle is zero. Our method will provide a convenient tool for comparing collisionless turbulence theories with, for example, observations of bipolar structure of supernova remnants and shell-like synchrotron-radiating structure.
Improved magnetic field generation efficiency and higher temperature spheromak plasmas
Authors: Wood R.D. , Hill D.N. , McLean H.S. , Hooper E.B. , Hudson B.F. , Moller J.M. , Romero-Talamás C.A.
Published: December 2008

New understanding of the mechanisms governing the observed magnetic field generation limits on the sustained spheromak physics experiment has been obtained. Extending the duration of magnetic helicity injection during the formation of a spheromak and optimizing the ratio of injected current to bias flux produce higher magnetic field plasmas with record spheromak electron temperatures. To explore magnetic field buildup efficiency limits, the confinement region geometry was varied resulting in improved field buildup efficiencies.
Equilibrium reconstruction of plasma profiles based on soft x-ray imaging in DIII-D
Authors: Qian J.P. , Lao L.L. , Ren Q.L. , Rinderknecht H. , Volpe F. , Zhang C. , Wan B.N.
Published: December 2008

The method of using internal magnetic surface information from soft x-ray (SXR) measurements to facilitate equilibrium reconstruction is explored. It is shown that useful information about the shape of the safety-factor q profile in DIII-D can be generally determined from the information inferred from surfaces of constant SXR emissivity. Comparisons of magnetic surfaces and the q profile reconstructed using external magnetic and SXR data against those using magnetic and motional Stark effect (MSE) data are presented. The reconstructed results using SXR and external magnetic data are found to reasonably agree with those derived from MSE and external magnetic data. The choice of an appropriate number of fitting parameters to reconstruct the q profile is also investigated.
Photodissociation Dynamics of Methanol and Ethanol at 157 nm
Authors: Yuan Kai-jun , Cheng Yuan , Wang Feng-yan , Yang Xue-ming
Published: December 2008

157 nm photodissociation of jet-cooled CH3OH and C2H5OH was studied using the high-n Rydberg atom time-of-flight (TOF) technique. TOF spectra of nascent H atom products were measured. Simulation of these spectra reveals three different atomic H loss processes: one from hydroxyl H elimination, one from methyl (ethyl) H elimination, and one from secondary dissociation of the methoxy (ethoxy) radical. The relative branching ratio indicates secondary dissociation of ethoxy is less important than that of methoxy. The average angular anisotropy parameter of methanol is negative (with 0.3), indicating the transition dipole moment is perpendicular to the COH plane. The slightly more negative value of ethanol (with 0.4) implies that ethanol has a longer rotational period. These experimental results indicate that both systems undergo fast internal conversion to the 3s surface after it is excited to the 3px surface, and then dissociate on the 3s surface. The translational energy distribution of the CH3O+H products reveals extensive CH3 rocking or CH3 umbrella excitation in the CH3O radical. However the vibrational structures are not resolved in the C2H5O radical.
Theoretical Studies on the Kinetics and Mechanisms of Reactions for Methyl Vinyl Ether and Ozone
Authors: Long Bo , Huang Ming-qiang , Wang Zhen-ya , Zhang Wei-jun
Published: December 2008

The interconversion between the two distinct isomers of methyl vinyl ether (MVE), the formation of the primary ozonides from O3-initated reactions of MVE, the transformation between the primary ozonides, and the subsequent fragmentation were studied using quantum chemical methods at the BHandHLYP/6311++G(d,p) level of theory for optimized geometries and frequency calculations and at the QCISD/631G(d,p) level for the single point energy calculations. The rate coefficients were calculated for the temperature range 280440 K by using the canonical transition state theory (TST). For ozone addition to MVE, there are two different possibilities discussed on the basis of two different possible orientations for ozone attack. The results of the theoretical study indicate that although the synperiplanar-MVE is 7.11 kJ/mol more stable than the antiperiplanar-MVE, the antiperiplanar-MVE plays a more important role in formation of the primary ozonides because the primary ozonides formed from the ozone addition antiperiplanar-MVE are more stable and the energy barriers corresponding to transition states are lower. The interconversion between the primary ozonides formed from the ozone addition to antiperiplanar-MVE is the most accessible compared with the transformations between other primary ozonides. The cleavage of the primary ozonides mainly leads to the formation of the CH2OO, which is in agreement with the experimental estimates. The calculated overall rate constant for the ozone-initiated reactions is 4.81017cm3/(molecules) at 298.15 K, which agrees with the experimental value for ethyl vinyl ether.
Defect Characterization of 6H-SiC Studied by Slow Positron Beam
Authors: Wang Hai-yun , Weng Hui-min , Zhou Xian-yi
Published: December 2008

The defect formation and annealing behavior in as-grown and electron-irradiated 6H-SiC wafers were investigated by variable-energy slow positron beam. For the n-type as-grown samples, it was found that annealing decreased the defect concentration due to recombination with interstitial, and when it was annealed at 1400C for 30 min in vacuum, a 20 nm thick Si layer was found on the top of SiC substrate, which is a direct proof of the Si atom diffusing to the surface when annealed at the high temperature stages. During the high temperature annealing stage, we found an obvious surface effect occurred that induced the higher S parameter close to the surface. This may be caused by the diffusion of the Si atoms to the surface during annealing. After 10 MeV electron irradiation of the n-type 6H-SiC, the positron effective diffusion length decreased from 86.2 nm to 39.1 nm. This shows that there are some defects created in n-type 6H-SiC. But in the p-type 6H-SiC irradiated by 10 MeV electrons, the change is very small. This may be because of the opposite charge of the vacancy defects. The same annealing behavior as that of as-grown 6H-SiC samples was also observed for the 1.8 MeV electron-irradiated 6H-SiC samples except that after being annealed at 300 C, its defect concentration increased. This may be explained as the generation of carbon vacancies, due to either the recombination between divacancies and silicon interstitial, or the charge of the charge states.
Hydrolysis of New Transplatin Analogue Containing One Aliphatic and One Planar Heterocyclic Amine Ligand: A Density Functional Theory Study
Authors: Gao Yan , Zhou Li-xin
Published: December 2008

Herein we give a theoretical study of the hydrolysis processes of a novel anticancer drug trans-[PtCl2(3-pico)(ipa)] (3-pico = 3-methylpyridine, ipa = isopropylamine). Two different models, model 1 relative to isolated reactant/product (R/P, wherein R = platinum complex+H2O, P = platinum complex+Cl) and model 2 relative to reactant complex/product complex (RC/PC, wherein RC = (platinum complex)(H2O), PC = (platinum complex)(Cl) are employed and the geometric structures are optimized at the B3LYP level of DFT method. It is found that the processes of the reactions follow the established theory for ligand substitution in square planar complexes; the geometries of the transition states (TS) agree with the previous related work and all of the reactions are endothermic. The effects originating from the inclusion of the attacking water/released chloride into the second coordination shell of platinum in RC/PC play an important role in the thermodynamic and kinetic profiles of the reactions, that is, the barrier heights of the reactions of model 2 are increased by 26.3 and 23.8 kJ/mol for step1 and step2 respectively, and the endothermicity is considerably decreased by 420.5 and 771.2 kJ/mol compared to model 1 in the gas phase. The consideration of the bulk solvation effects increase the barrier heights for both steps of model 1 by 27.6 and 6.7 kJ/mol respectively, whereas it reduces the barrier heights by 7.9 and 29.3 kJ/mol for model 2. The reaction energies are all decreased, especially for model 1, indicating more stable complexes solvated in the bulk aqueous solution than in the gas phase. Additionally, to get an accurate energy picture of the title complex, the relative free energies derived from the DFT-SCRF (density functional theory self-consistent field) calculations are compared with the relative total energies. The results are that activation energies rise for the first hydrolysis and fall for the second hydrolysis for all the systems, and for all the systems, the barrier height of the second hydrolysis is always higher than that of the first step. The rate constants indicate that transplatin analogue is kinetically comparable to cisplatin and its analogue in the hydrolysis process.