bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuromonitoring in Thyroid Surgery: Attitudes, Usage Patterns, and Predictors of Use Among Endocrine Surgeons
Authors: Sturgeon Cord , Sturgeon Treena , Angelos Peter
Published: August 2008

Background

The use of neuromonitoring in thyroid surgery is controversial. Attitudes about neuromonitoring, usage patterns, and predictors of use have not been formally studied. We hypothesized that attitudes would predict usage patterns and that the predominant strategy among endocrine surgeons would be no neuromonitoring during thyroid surgery.

Methods

Members of the American Association of Endocrine Surgeons and registrants of the 2006 annual meeting were surveyed by e‐mail. An Internet‐based survey composed of simple answer and Likert questions was used. Central tendency was evaluated by modal response. Significance was analyzed by the chi‐squared test, and strength of association was calculated by Cramér’s V.

Results

A total of 117 surveys were completed (41%). Respondents were placed into two groups based on use (37.1%), or nonuse (62.9%) of neuromonitoring. The use category was composed of routine (13.8%) and selective (23.3%) users. The nonuse category was composed of those who have never used neuromonitoring (49.1%) and those who have abandoned its use (13.8%). Nonusers were older (p = 0.023) and reported a lower case volume (p = 0.003), less familiarity with the technology (p < 0.001), and less access to the equipment (p < 0.001). Nonusers reported a lower frequency of patient‐initiated discussions about neuromonitoring (p < 0.001) and were less likely to initiate a discussion with patients (p < 0.001). In total, 56% of users and 90% of nonusers believed neuromonitoring does not improve the safety of thyroidectomy (p < 0.01). There was no difference in perceived nerve injury rate between users and nonusers. Users agreed that benefits include facilitating identification of the recurrent laryngeal nerve, facilitating resident education, improving patient outcomes, and decreasing liability risk, whereas nonusers disagreed with these statements. Nonusers believed that neuromonitoring can lead to reliance on technology and loss of surgical technique or judgment, but users disagreed. There was consensus of opinion that neuromonitoring allows identification of an intact nerve, can lead to a false sense of security, drives up costs, is beneficial in <10% of cases, does not shorten the length of the procedure, and does not prevent nerve injury.

Conclusions

Usage is associated with surgeon age, case volume, equipment availability and familiarity, beliefs about the degree of benefit, and frequency of patient or doctor initiated discussions.
HA/GSA‐Rmax Ratio as a Predictor of Postoperative Liver Failure
Authors: Kaibori Masaki , Ha‐Kawa Sang Kil , Ishizaki Morihiko , Matsui Kosuke , Saito Takamichi , Kwon A‐Hon , Kamiyama Yasuo
Published: August 2008

Background

Postoperative mortality after hepatectomy remains high compared with other types of surgery in patients who have cirrhosis or chronic hepatitis. Although there are several useful perioperative markers of liver dysfunction, there are no standard markers for predicting postoperative liver failure. This study investigated risk factors for postoperative liver failure after resection of hepatocellular carcinoma to detect markers that could identify candidates for hepatectomy.

Methods

Perioperative risk factors for liver failure after hepatectomy were analyzed in 191 patients with hepatocellular carcinoma. Multivariate logistic regression analysis was done to investigate factors with a significant independent influence among 35 variables. The ratio of serum hyaluronic acid to the maximum removal rate of technetium‐99 m diethylenetriaminepentaacetic acid galactosyl human serum albumin (hyaluronate/GSA‐Rmax ratio) was calculated.

Results

Liver failure occurred postoperatively in 16 patients, 3 of whom died. The hyaluronate/GSA‐Rmax ratio was a risk factor for postoperative liver failure by univariate analysis and was the only risk factor according to multivariate analysis. All three patients who died had a hyaluronic acid/GSA‐Rmax ratio ≥ 500 mg min/dl. This ratio had a sensitivity of 88% and a specificity of 92% for predicting liver failure.

Conclusions

To reduce postoperative liver failure, preoperative planning should employ various measures of the hepatic functional reserve, including tests of both parenchymal and nonparenchymal liver function. The hyaluronate/GSA‐Rmax ratio can predict liver failure after hepatectomy, and a ratio ≥ 500 mg min/dl is a relative contraindication to liver resection.
Mathematische Modelle in der Populationsgenetik
Authors: Caliebe A.
Published: August 2008

In der mathematischen Populationsgenetik wird der Einfluss von Selektion und Mutation auf die zeitliche Entwicklung der genetischen Struktur einer Population modelliert. Da alle Populationen und erst recht die für ihre Untersuchung zur Verfügung stehenden Stichproben endlich sind, spielen die stochastischen Aspekte der verwendeten Modelle eine besondere Rolle. Wichtige populationsgenetische Modelle sind das Wright-Fisher-Modell und das Koaleszenzmodell für die Genealogie von Stichproben sowie das „infinite alleles model“ und das „infinite sites model“ für die darin ablaufenden Mutationsprozesse.
The Chalcedon Problem: Rousas John Rushdoony and the Origins of Christian Reconstructionism
Authors: Worthen Molly
Published: August 2008

According to the town criers of liberal American journalism, readers must wake up and do something. Hide your children—there is a movement afoot among conservative Christians to take over our country and give America a theocratic makeover. A slew of magazine articles and books—with apocalyptic titles such as American Theocracy and The Baptizing of America: The Religious Right's Plans for the Rest of Us1— announced conservative Christians' backward views on social and political issues, insidious webs of government influence, and intentions to return America to its supposedly Christian roots. Most of these authors devoted at least a few pages to an obscure religious movement and a man with a curious name: Christian reconstructionism and R. J. Rushdoony.
Mendicants, the Communes, and the Law
Authors: Powell James M.
Published: August 2008

The present essay briefly examines evidence for the development of the mendicant orders, focusing on their relationship to important members of the middle and upper classes in the communes as one of the chief ways in which they gained popularity and public support. These orders came into existence between the late twelfth century and the latter half of the thirteenth. Their increased involvement with the laity was both a direct product of their concern with the needs of the contemporary church and a source of conflict between them and the existing monastic and diocesan clergy. The experience of the Humiliati in various dioceses in northern Italy illustrates an important point, namely the growing divisions within the church and the tendency to label various groups as heretical. The condemnation of the Humiliati and other groups by Pope Lucius III in Verona in 1183 is a sign of the increasing sensitivity to the danger of heresy among the laity within the leadership of the church.
Gender and academic discourse: Global restrictions and local possibilities
Authors: SCHLEEF ERIK
Published: August 2008

This article investigates the academic speech of humanities and natural science instructors and students in 32 lectures and interactional classes at a U.S. university. It examines how structural markers, questions, question tags, and turn-initial response tokens contribute to variations of style in response to academic division, context, gender, and communicative role in academic discourse. Data analysis couples qualitative discourse analytic methods with a quantitative sociolinguistic analysis. The quantitative analysis shows the factors of communicative role, academic discipline, and speech mode – not gender – to be the most influential in the use of the structures investigated. It is argued that the lack of significant results for gender arise from global discourse restrictions in academic speech. However, despite the global restrictions shown by quantitative analysis, qualitative analysis suggests that such restrictions can be overridden, especially in contexts of structural breaks and disruptions of information flow, and that features that contribute to more interactional and cooperative speech styles, frequently linked to females, can emerge.
A comparison of visuomotor cue integration strategies for object placement and prehension
Authors: GREENWALD HAL S. , KNILL DAVID C.
Published: August 2008

Visual cue integration strategies are known to depend on cue reliability and how rapidly the visual system processes incoming information. We investigated whether these strategies also depend on differences in the information demands for different natural tasks. Using two common goal-oriented tasks, prehension and object placement, we determined whether monocular and binocular information influence estimates of three-dimensional (3D) orientation differently depending on task demands. Both tasks rely on accurate 3D orientation estimates, but 3D position is potentially more important for grasping. Subjects placed an object on or picked up a disc in a virtual environment. On some trials, the monocular cues (aspect ratio and texture compression) and binocular cues (e.g., binocular disparity) suggested slightly different 3D orientations for the disc; these conflicts either were present upon initial stimulus presentation or were introduced after movement initiation, which allowed us to quantify how information from the cues accumulated over time. We analyzed the time-varying orientations of subjects’ fingers in the grasping task and those of the object in the object placement task to quantify how different visual cues influenced motor control. In the first experiment, different subjects performed each task, and those performing the grasping task relied on binocular information more when orienting their hands than those performing the object placement task. When subjects in the second experiment performed both tasks in interleaved sessions, binocular cues were still more influential during grasping than object placement, and the different cue integration strategies observed for each task in isolation were maintained. In both experiments, the temporal analyses showed that subjects processed binocular information faster than monocular information, but task demands did not affect the time course of cue processing. How one uses visual cues for motor control depends on the task being performed, although how quickly the information is processed appears to be task invariant.
A NEW FRAMEWORK FOR THE ANALYSIS OF INEQUALITY
Authors: Cunha Flavio , Heckman James
Published: August 2008

This paper presents a new framework for analyzing inequality that moves beyond the anonymity postulate. We estimate the determinants of sectoral choice and the joint distributions of outcomes across sectors. We determine which components of realized earnings variability are due to uncertainty and which components are due to components of human diversity that are forcastable by agents. Using our tools, we can determine how policies shift persons across sectors and outcome distributions across sectors.
Assessing and supporting body image and sexual concerns for young women with breast cancer: a literature review
Authors: Kinamore Cher
Published: August 2008

Background: Breast cancer is the most common cancer and most common cancer cause of death in women aged 20–49 years in Canada. Developing a functional definition of ‘young’ is imperative in assessing and providing appropriate emotional support to the unique body image and sexuality concerns facing ‘young’ women with breast cancer. These concerns require proper assessment in order to provide appropriate interventions.

Aims and objectives: To seek a functional definition of ‘young’ and to determine what body image and sexuality assessment tools and interventions are the most appropriate for young women with breast cancer.

Methods: A literature search was undertaken to determine what body image and sexuality assessment tools and interventions are available and relevant to young women with breast cancer. Also, the assessment and interventions available to this patient cohort in the author's clinic were explored.

Conclusions: Body image and sexuality questionnaires encourage young women and health-care providers (HCPs) to openly discuss these issues. Annon's PLISSIT model is an assessment and intervention strategy that enables HCPs to adequately assess and refer young women to suitable programs such as support groups and counsellors. The multi-disciplinary team should provide continuous emotional assessment and support throughout the cancer journey by collaborating to develop the best interventional strategies to the patient and her family.
Pilot study: rectal contouring variability in patients treated with radical radiotherapy for prostate cancer: impact on rectum dose–volume histograms
Authors: Martin Jacqueline E. , Kirkbride P.
Published: August 2008

Purpose: The organ at risk in prostate radiotherapy is the anterior rectal wall . This pilot study was conducted to quantify the inter-observer variability of rectal contouring in conformal prostate radiotherapy planning using four contouring methods and to determine a standard rectal contouring definition.

Methods and materials: Ten patients with T1/T2 disease and six clinical oncologists were recruited. Two cross-sectional and two length limits generated four rectal volumes. Each clinician contoured the four volumes for each patient and the dose–volume histograms (DVHs) were analysed. The percentage rectal volume receiving 20%, 50%, 80%, 90% and 95% of the total delivered dose and the mean and median rectal doses were calculated. Data were presented as mean ± 2 standard deviations.

Results: The Sh Rec method (contouring the rectum including its contents extending from 2 cm above the upper limit of the prostate to 2 cm below the prostatic apex) was the least variable in the 80%, 90% and 95% percentage ranges. The mean difference in Sh Rec-contoured volume was 18.7 cm3 (± 22.3 cm3).

Conclusions: The Sh Rec-contouring method showed the least inter-observer variability. The results are informative and will help define a standard rectal contouring method.
PP4 is a γH2AX phosphatase required for recovery from the DNA damage checkpoint
Authors: Nakada Shinichiro , Chen Ginny I , Gingras Anne‐Claude , Durocher Daniel
Published: August 2008

Phosphorylation of histone H2AX on Ser 139 (γH2AX) is one of the earliest events in the response to DNA double‐strand breaks; however, the subsequent removal of γH2AX from chromatin is less understood, despite being a process tightly coordinated with DNA repair. Previous studies in yeast have identified the Pph3 phosphatase (the PP4C orthologue) as important for the dephosphorylation of γH2AX. By contrast, work in human cells attributed this activity to PP2A. Here, we report that PP4 contributes to the dephosphorylation of γH2AX, both at the sites of DNA damage and in undamaged chromatin in human cells, independently of a role in DNA repair. Furthermore, depletion of PP4C results in a prolonged checkpoint arrest, most likely owing to the persistence of mediator of DNA damage checkpoint 1 (MDC1) at the sites of DNA lesions. Taken together, these results indicate that PP4 is an evolutionarily conserved γH2AX phosphatase.
Novel function of the class I bHLH protein Daughterless in the negative regulation of proneural gene expression in the Drosophila eye
Authors: Lim Janghoo , Jafar‐Nejad Hamed , Hsu Ya‐Chieh , Choi Kwang‐Wook
Published: August 2008

Two types of basic helix–loop–helix (bHLH) family transcription factor have functions in neurogenesis. Class II bHLH proteins are expressed in tissue‐specific patterns, whereas class I proteins are broadly expressed as general cofactors for class II proteins. Here, we show that the Drosophila class I factor Daughterless (Da) is upregulated by Hedgehog (Hh) and Decapentaplegic (Dpp) signalling during retinal neurogenesis. Our data suggest that Da is accumulated in the cells surrounding the neuronal precursor cells to repress the proneural gene atonal (ato), thereby generating a single R8 neuron from each proneural cluster. Upregulation of Da depends on Notch signalling, and, in turn, induces the expression of the Enhancer‐of‐split proteins for the repression of ato. We propose that the dual functions of Da—as a proneural and as an anti‐proneural factor—are crucial for initial neural patterning in the eye.
Superclusters and the large-scale structure of the Universe
Authors: Helfand David J.
Published: August 2008

From the beginning of this century, study of the origin and evolution of the Universe has been informed by the Cosmological Principle: The Universe is homogeneous and isotropic. On the largest observable scale, that of the blackbody cosmic background radiation, this statement has been confirmed to a high degree of accuracy; spatial inhomogeneities in the temperature of the background radiation are less than 1 part in 104. On the human scale, the Principle is patently absurd. A question of considerable current interest is to ascertain on what scale the postulate breaks down. Observers have recently been working hard on mapping structure on scales of 106 to 3×108 light years, and theorists have been exploiting the increasingly important connections between particle physics and cosmology in an attempt to understand how these structures come to be.
Novel laser for fiber-optic communication
Authors: Schwarzschild Bertram M.
Published: August 2008

A new kind of semiconductor laser, developed by Won-Tien Tsang and his colleagues at Bell Labs, has demonstrated a number of remarkable capabilities that promise to be of considerable importance for fiber-optic communication. This cleaved-coupled-cavity semiconductor laser, nicknamed the C3 laser, is able to generate essentially monochromatic pulses of infrared light at repetition rates in excess of a gigahertz. Furthermore, one can electronically switch this pulsed monochromatic output from one wavelength to another on a nanosecond time scale.
The evolution of SLAC and its programs
Authors: Panofsky Wolfgang K. H.
Published: August 2008

In 1957 Stanford University proposed to the Federal government the construction of a two-mile-long linear electron accelerator. Originally called the “Monster,” the machine was to be very much larger than any that had been previously carried out under the aegis of a single university. It was also an electron rather than a proton machine, and thus not in the mainstream of particle accelerators at the time. However, it seemed clear that there was useful physics to be learned from electron scattering, and the proposal for “Project M” was well received. Renamed the Stanford Linear Accelerator Center a few years later, the proposal was accepted and funded. Ground was broken in 1962, and the accelerator produced its first beam in 1966.
Ultrasonic excitations in He3-B
Authors: Lubkin Gloria B.
Published: August 2008

Of the three superfluid phases of He3, the one labeled He3-B has often been considered the “dull” superfluid because it lacked the interesting anisotropies of the A and A1 phases. The B phase has now become more intriguing: Over the past few years, ultrasonic spectroscopy has uncovered ever more details of the excited states of He3-B, and has revealed that the collective excitations of this many-body system have a form reminiscent of simple atomic spectra. As Peter Wolfle from the Technical University of Munich told us, the superfluid He3-B acts like “a giant molecule in momentum space.” The excited states, observed through strong absorption peaks in the transmission of ultrasound, have essentially the structure one would expect from a triplet p-wave pairing of the helium atoms. Measurements have uncovered effects that are the equivalent of Zeeman splitting and the Paschen-Back effect. Some of these measurements were described at the International Symposium on Quantum Fluids and Solids held at Sanibel Island, Florida, in April. (The story on page 23 describes other work on He3-B presented at the same meeting.)
Hadron spectroscopy and quarks
Authors: Isgur Nathan , Karl Gabriel
Published: August 2008

Our understanding of the ultimate structure of matter has advanced greatly in the last few years. It was nearly twenty years ago that Murray Gell-Mann and George Zweig gave us the key to much of this understanding with their revolutionary proposals that protons, neutrons and all other strongly interacting particles—the hadrons—are made of quarks, a theretofore unobserved kind of particle. Over the last ten years, this proposal has become firmly established even though we have not observed free quarks directly. More recent research has found that forces between quarks are extremely simple and universal—the same for all types of quarks—and that these forces explain why free quarks cannot be seen. In this article we will look at hadron spectroscopy, which has been one of the main venues for this great progress.
Current trends in atomic spectroscopy
Authors: Wynne James J.
Published: August 2008

The last three decades have seen a renaissance in atomic spectroscopy. After many years of important advances in pursuit of its own intellectual goals, the field began a major expansion in the 1950s as urgent demands for spectral data came from industry, the atomic-energy program, the space program and the defense department. Today, atomic spectroscopy is a modern, active and basic science. Atomic spectroscopists study the effects of collisions, electric and magnetic fields, photoionization, and other interactions between atoms and their environment in ways that would have been impossible or forbiddingly complex just a few years ago. They routinely use such experimental tools as lasers, synchrotron light sources, electron spectrometers, ion traps and fast ion beams (figure 1). They use such theoretical tools such as quantum-defect theory, many-body perturbation theory and group theory to study the structure of isolated atoms in greater detail and with greater precision than ever before. An important result of this new work is that atomic spectroscopy has increased its impact on diverse areas of physics as well as on its traditional area of contribution—the study of the electronic structure of atoms.
Surface spectroscopy
Authors: Demuth Joe , Avouris Phaedon
Published: August 2008

In the last 15 years there has been a tremendous growth in the field of surface science, all largely made possible by the development and application of various surface spectroscopies. In this article we hope to provide a picture of a few of the principal surface spectroscopic methods and how they are applied to answer important questions in surface science. In particular, we hope to provide the reader with a perspective of the unique considerations and technical problems associated with applying spectroscopic methods to surfaces. While the particular examples we discuss are the results of colleagues and coworkers at the Thomas J. Watson IBM laboratories, we believe they are representative of the types of surface studies and spectroscopies performed in the field in general.
Storage-ring free-electron laser operates in the visible
Authors: Schwarzschild Bertram M.
Published: August 2008

The successful generation of a 6500-Å free-electron laser beam this summer at the French electron storage ring ACO represents a number of firsts. This culmination of a three-year effort by an Orsay–Stanford collaboration at Orsay's LURE (Laboratoire pour l'Utilisation du Rayonnement Electromagnetique) synchrotron-light laboratory is the first operation of a free-electron laser oscillator at a visible-light wavelength. It is, furthermore, the first operation of a free-electron laser oscillator at any wavelength using the circulating electron beam of a storage ring. The Orsay–Stanford FEL is also the first device to achieve laser oscillation with an “optical klystron”—a modified wiggler design suggested by N. A. Vinokurov and Alexander Skrinsky at Novosibirsk (in 1977) for enhancing the gain of free-electron lasers.
Neutrons in science and technology
Authors: Bromley D. Allan
Published: August 2008

In the four decades since the first controlled nuclear chain reaction made them available in abundance, neutrons have had a revolutionary impact on much of science and technology. Best known, perhaps, are the neutron's roles in energy production and nuclear medicine. However, this particle has made, and is making, enormous contributions in dozens of other areas of science and technology.
First plasma at Princeton's Tokamak Fusion Test Reactor
Authors: Schwarzschild Bertram M.
Published: August 2008

The first of a new generation of large tokamaks was completed just in time for Christmas. Princeton's Tokamak Fusion Test Reactor achieved its first test plasma in the early hours of 24 December. TFTR is one of four new tokamaks large enough to achieve plasma conditions that are expected to suffice for the demonstration of “scientific breakeven”—the output of fusion power equal to the input of heating power from external sources.
Teaching about the arms race
Authors: Schroeer Dietrich
Published: August 2008

If progress is to be made toward peace, public education on arms-race issues is crucial both in the short run and for the long term. Because technical information is invariably essential to an understanding of issues, physicists can make a major contribution. However, educational efforts on the arms race face great difficulties, which we must first recognize if we are to overcome them:

• Teaching about the arms race has in the past been a cyclical activity, rising and falling in parallel with public concern. These cycles are not all bad; the arms race is a real problem, not just an academic one, and hence it must be addressed whenever it surfaces in the political arena. But cycles tend to inject an aura of crisis into discussions, providing short-term motivation at the cost of credibility and efficiency in the long run. The longer-term approach has more educational implications. It means that arms-race education must be general enough to be useful for analyzing unknown future issues. The danger with short-term education is that by the time current educational efforts have roused public support for, say, a new round of arms control, the political need and opportunity may have passed.

• The arms race presents interdisciplinary problems. Physicists may be unaware of contributions other disciplines can make to this issue and insensitive to their own biases.

• There is little encouragement for physicists undertaking arms-race educational efforts. Peer recognition for either research or teaching in the area is sparse. There is little financial support for this kind of work. The DOD looks for technical research of direct use to its missions, the Arms Control and Disarmament Agency is in disfavor within the government, the National Science Foundation has difficulty supporting anything involving the social sciences or science education and the Ford Foundation also appears to be decreasing its support for these activities.
The early universe and high-energy physics
Authors: Schramm David N.
Published: August 2008

15 billion years ago, an experiment was carried out that related to the interaction between cosmology and particle physics and the unification of physics in general. This is the experiment that we call the Big Bang. It resulted in about 1090 bits of data spread out over 1028 cm3. We know the original apparatus had about 1019 GeV (see figure 1), but, unfortunately, the graduate student who designed this equipment is no longer around, and, as a result, she can't tell us exactly what she did. So we have to try to piece together the data on our own to see if we can understand what happened in this experiment. From some of the data that we've been able to assemble—for example, from observing the 3-K background radiation—we know the early universe was hot and dense. We also know that about one-quarter of the isotope helium-4. This figure is really rather amazing. The sum total of all the other heavier elements (carbon, oxygen, iron and so on) makes up less than 2 percent of the mass of the Universe. Stars make these other heavy elements, but they make them in total abundances of the order of a fraction of a percent. Yet the Universe is 25% helium-4—and this is exactly the figure the standard theoretical model of the Big Bang predicts!
How random is a coin toss?
Authors: Ford Joseph
Published: August 2008

Probabilistic and deterministic Descriptions of macroscopic phenomena have coexisted for centuries. During the period 1650–1750, for example, Newton developed his calculus of determinism for dynamics while the Bernoullis simultaneously constructed their calculus of probability for games of chance and various other many-body problems. In retrospect, it would appear strange indeed that no major confrontation ever arose between these seemingly contradictory world views were it not for the remarkable success of Laplace in elevating Newtonian determinism to the level of dogma in the scientific faith. Thereafter, probabilitistic descriptions of classical systems were regarded as no more than useful conveniences to be invoked when, for one reason or another, the deterministic equations of motion were difficult or impossible to solve exactly. Moreover, these probabilistic descriptions were presumed derivable from the underlying determinism, although no one ever indicated exactly how this feat was to be accomplished.
New inflationary universe: an alternative to Big Bang?
Authors: Levi Barbara G.
Published: August 2008

Ever since the Big Bang, the universe has been growing at a rate proportional to a fractional power of time—or has it been? Could there have been an instant, in the earliest moments of time, when the expansion was far more rapid, producing in this brief instant a radial increase 25 orders of magnitude greater than that which would otherwise have occurred? If such an inflationary period did occur, it could account for some features of our observable universe hitherto unexplained by the standard theory of the Big Bang. These features include the remarkable homogeneity of the universe, its sparse population of magnetic monopoles (if there are any at all) and the pinpoint balance it maintains between an infinitely expanding and an eventually collapsing condition. In short, inflation may be far better news for cosmology than it is for the economy.
Quiteron superconducting switch acts like a transistor
Authors: Schwarzschild Bertram M.
Published: August 2008

With the advent of very-large-scale integration of microelectronic circuits comes the promise of enormously powerful computers; 104 circuits or 106 bits of memory per chip are reasonable prospects. What is required of circuit elements if we are to advance by one or two orders of magnitude beyond the 107 instructions per second that characterize today's most powerful general-purpose computers?
Computers in physics: an overview
Authors: Hamann Donald R.
Published: August 2008

In the eyes of the general public, the computer has changed from a remote and recalcitrant source of error on monthly bills to a friendly and increasingly common household appliance. Time magazine, which names a “Man of the Year,” in 1982 named the computer instead, and The New York Times runs a weekly computer column. With the popular press full of the subject, it hardly seems necessary to tell an audience of physicists that a computer consists of a central processing unit, a high-speed memory, mass-storage disks and so on. A large fraction of the total number of scientists active in research or development have ready access to computers. I can safely assume that my readers have some level of familiarity with the basic operation of modern computers and with a few uses of computers in their fields of specialization. In this article, then, I will address a set of topics of special concern to physicists in the hope that doing so will stimulate further discussion. One indisputable fact is that the presence of computers will continue to expand in our science as in the rest of our lives, and some thoughtful reflection on where we are going and how we shall get there should be time well spent.
Condensed-matter physics
Authors: Hirsch Jorge E. , Scalapino Douglas J.
Published: August 2008

Computers are playing an integral role in both experimental and theoretical condensed-matter physics: In laboratories they are being used to control experiments as well as to gather and analyze data; in theoretical studies they provide the means for making detailed predictions for realistic models, for exploring systems that cannot be realized in the laboratory, such as four-dimensional systems undergoing phase transitions or materials under extreme conditions of pressure or temperature, and for complicated symbolic manipulations. Often computers provide an essential link between experiment and theory, allowing experimentalists to test critically theoretical predictions and allowing theorists to make predictions for realistic models.
miR-34a repression of SIRT1 regulates apoptosis
Authors: Yamakuchi Munekazu , Ferlito Marcella , Lowenstein Charles J.
Published: August 2008

MicroRNA 34a (miR-34a) is a tumor suppressor gene, but how it regulates cell proliferation is not completely understood. We now show that the microRNA miR-34a regulates silent information regulator 1 (SIRT1) expression. MiR-34a inhibits SIRT1 expression through a miR-34a-binding site within the 3′ UTR of SIRT1. MiR-34 inhibition of SIRT1 leads to an increase in acetylated p53 and expression of p21 and PUMA, transcriptional targets of p53 that regulate the cell cycle and apoptosis, respectively. Furthermore, miR-34 suppression of SIRT1 ultimately leads to apoptosis in WT human colon cancer cells but not in human colon cancer cells lacking p53. Finally, miR-34a itself is a transcriptional target of p53, suggesting a positive feedback loop between p53 and miR-34a. Thus, miR-34a functions as a tumor suppressor, in part, through a SIRT1-p53 pathway.
Generation of functional erythrocytes from human embryonic stem cell-derived definitive hematopoiesis
Authors: Ma Feng , Ebihara Yasuhiro , Umeda Katsutsugu , Sakai Hiromi , Hanada Sachiyo , Zhang Hong , Zaike Yuji , Tsuchida Eishun , Nakahata Tatsutoshi , Nakauchi Hiromitsu , Tsuji Kohichiro
Published: August 2008

A critical issue for clinical utilization of human ES cells (hESCs) is whether they can generate terminally mature progenies with normal function. We recently developed a method for efficient production of hematopoietic progenitors from hESCs by coculture with murine fetal liver-derived stromal cells. Large numbers of hESCs-derived erythroid progenitors generated by the coculture enabled us to analyze the development of erythropoiesis at a clone level and investigate their function. The results showed that the globin expression in the erythroid cells in individual clones changed in a time-dependent manner. In particular, embryonic ε-globin-expressing erythroid cells from individual clones decreased, whereas adult-type β-globin-expressing cells increased to ≈100% in all clones we examined, indicating that the cells undergo definitive hematopoiesis. Enucleated erythrocytes also appeared among the clonal progeny. A comparison analysis showed that hESC-derived erythroid cells took a similar differentiation pathway to human cord blood CD34
+
progenitor-derived cells when examined for the expression of glycophorin A, CD71 and CD81. Furthermore, these hESC-derived erythroid cells could function as oxygen carriers and had a sufficient glucose-6-phosphate dehydrogenase activity. The present study should provide an experimental model for exploring early development of human erythropoiesis and hemoglobin switching and may help in the discovery of drugs for hereditary diseases in erythrocyte development.
Four miRNAs associated with aggressiveness of lymph node-negative, estrogen receptor-positive human breast cancer
Authors: Foekens John A. , Sieuwerts Anieta M. , Smid Marcel , Look Maxime P. , de Weerd Vanja , Boersma Antonius W. M. , Klijn Jan G. M. , Wiemer Erik A. C. , Martens John W. M.
Published: August 2008

In this study, we quantified 249 mature micro-RNA (miRNA) transcripts in estrogen receptor-positive (ER+) primary breast tumors of patients with lymph node-negative (LNN) disease to identify miRNAs associated with metastatic capability. In addition, the prognostic value of the candidate miRNAs was determined in ER−/LNN breast cancer. Unsupervised analysis in a prescreening set of 38 patients identified three subgroups predominantly driven by three miRNA signatures: an ER-driven luminal B-associated miRNA signature, a stromal miRNA signature, and an overexpressed miRNA cluster located on chromosome 19q23, but these intrinsic miRNA signatures were not associated with tumor aggressiveness. Supervised analysis in the initial subset and subsequent analysis in additional tumors significantly linked four miRNAs (miR-7,miR-128a,miR-210, andmiR-516–3p) to ER+/LNN breast cancer aggressiveness (n= 147) and one miRNA (miR-210) to metastatic capability in ER−/LNN breast cancer (n= 114) and in the clinically important triple-negative subgroup (n= 69) (allP< 0.05). Bioinformatic analysis coupledmiR-210to hypoxia/VEGF signaling,miR-7andmiR-516–3pto cell cycle progression and chromosomal instability, andmiR-128ato cytokine signaling. In conclusion, our work connects four miRNAs to breast cancer progression and to several distinct biological processes involved therein.
Selective death of autoreactive T cells in human diabetes by TNF or TNF receptor 2 agonism
Authors: Ban Liqin , Zhang Jack , Wang Limei , Kuhtreiber Willem , Burger Douglas , Faustman Denise L.
Published: August 2008

Human autoimmune (AI) diseases are difficult to treat, because immunosuppressive drugs are nonspecific, produce high levels of adverse effects, and are not based on mechanistic understanding of disease. Destroying the rare autoreactive T lymphocytes causing AI diseases would improve treatment. In animal models, TNF selectively kills autoreactive T cells, thereby hampering disease onset or progression. Here, we seek to determine, in fresh human blood, whether TNF or agonists of TNF selectively kill autoreactive T cells, while sparing normal T cells. We isolated highly pure CD4 or CD8 T cells from patients with type 1 diabetes (n= 675), other AI diseases, and healthy controls (n= 512). Using two cell death assays, we found that a subpopulation of CD8, but not CD4, T cells in patients' blood was vulnerable to TNF or TNF agonist-induced death. One agonist for the TNFR2 receptor exhibited a dose-response pattern of killing. In type 1 diabetes, the subpopulation of T cells susceptible to TNF or TNFR2 agonist-induced death was traced specifically to autoreactive T cells to insulin, a known autoantigen. Other activated and memory T cell populations were resistant to TNF-triggered death. This study shows that autoreactive T cells, although rare, can be selectively destroyed in isolated human blood. TNF and a TNFR2 agonist may offer highly targeted therapies, with the latter likely to be less systemically toxic.
Therapeutic effect against human xenograft tumors in nude mice by the third generation microtubule stabilizing epothilones
Authors: Chou Ting-Chao , Zhang Xiuguo , Zhong Zi-Yang , Li Yong , Feng Li , Eng Sara , Myles David R. , Johnson Robert , Wu Nian , Yin Ye Ingrid , Wilson Rebecca M. , Danishefsky Samuel J.
Published: August 2008

The epothilones represent a promising class of natural product-based antitumor drug candidates. Although these compounds operate through a microtubule stabilization mechanism similar to that of taxol, the epothilones offer a major potential therapeutic advantage in that they retain their activity against multidrug-resistant cell lines. We have been systematically synthesizing and evaluating synthetic epothilone congeners that are not accessible through modification of the natural product itself. We report herein the results of biological investigations directed at two epothilone congeners: iso-fludelone and iso-dehydelone. Iso-fludelone, in particular, exhibits a number of properties that render it an excellent candidate for preclinical development, including biological stability, excellent solubility in water, and remarkable potency relative to other epothilones. In nude mouse xenograft settings, iso-fludelone was able to achieve therapeutic cures against a number of human cancer cell lines, including mammarian-MX-1, ovarian-SK-OV-3, and the fast-growing, refractory, subcutaneous neuroblastoma-SK-NAS. Strong therapeutic effect was observed against drug-resistant lung-A549/taxol and mammary-MCF-7/Adr xenografts. In addition, iso-fludelone was shown to exhibit a significant therapeutic effect against an intracranially implanted SK-NAS tumor.
Chromatin-bound mitogen-activated protein kinases transmit dynamic signals in transcription complexes in β-cells
Authors: Lawrence Michael C. , McGlynn Kathleen , Shao Chunli , Duan Lingling , Naziruddin Bashoo , Levy Marlon F. , Cobb Melanie H.
Published: August 2008

MAPK pathways regulate transcription through phosphorylation of transcription factors and other DNA-binding proteins. In pancreatic β-cells, ERK1/2 are required for transcription of the insulin gene and several other genes in response to glucose. We show that binding of glucose-sensitive transcription activators and repressors to the insulin gene promoter depends on ERK1/2 activity. We also find that glucose and NGF stimulate the binding of ERK1/2 to the insulin gene and other promoters. An ERK1/2 cascade module, including MEK1/2 and Rsk, are found in complexes bound to these promoters. These findings imply that MAPK-containing signaling complexes are positioned on sensitive promoters with their protein substrates to modulate transcription
in situ
in response to incoming signals.
Fluoroscopy-guided sacroplasty: special focus on preoperative planning from three-dimensional computed tomography
Authors: Gjertsen Ø. , Schellhorn T. , Nakstad P. H.
Published: August 2008

Background: Osteoporotic sacral insufficiency fractures are usually spontaneous or caused by discrete traumas. The fluoroscopic anatomy of the sacrum can be difficult to understand, and this is why sacroplasty is considered more challenging than ordinary vertebroplasties.

Purpose: To demonstrate the planning of the procedure and the effectiveness of treatment with sacroplasty by means of three-dimensional computed tomography (3D CT) by combining multiplanar reconstructions (MPR) and volume-rendering technique (VRT).

Material and Methods: Five elderly, osteoporotic patients with intense pelvic and hip pain underwent weeks of inconclusive clinical and radiological diagnostic efforts. Correct diagnosis was finally attained with magnetic resonance imaging (MRI) and CT. Plain radiographs rarely show fractures, and MR or CT examinations are necessary to demonstrate longitudinal fractures. The procedures were performed with digital biplane equipment using preoperative 3D CT planning procedures. Polymethyl methacrylate (PMMA) was injected to fill the fracture sites.

Results: The fractures were successfully treated with sacroplasty using PMMA. A new technique, which involves placing the needles along the long axis of the sacrum, was optimized to the individual patients’ fractures and sacral anatomy by meticulous planning on a workstation with 3D CT data sets. It was technically successful in all five cases. Four of the five patients had sustained pain relief.

Conclusion: Sacral insufficiency fractures are not uncommon and should be considered in the elderly population with low back pain. Sacroplasty using the optimized “long-axis technique” gave almost immediate pain relief for all five patients in our study material. No complications were observed.
Anatomy of an Act
Authors: Bentley David
Published: August 2008

The Terrorism Act 2000 was intended to be a single code of anti-terrorism law. David Bentley recalls the drafting of the Bill
A Section Too Far?
Authors: Burton John
Published: August 2008

John Burton questions whether it is really necessary to criminalise the encouragement of terrorism in such broad legislation
Articles of Terror
Authors: Khan Imran
Published: August 2008

Laws have been so widely drafted that we no longer know what is permissible, writes Imran Khan
Seeds of Spring
Authors: Klima Ivan , Short David
Published: August 2008

Ivan Klíma recalls the brave stand he took with fellow writers against censorship
Threats and Promises
Authors: Macdonald Ken
Published: August 2008

Ken Macdonald, director of public prosecutions, considers a shifting fault line
Free Speech for All
Authors: Neier Aryeh
Published: August 2008

Aryeh Neier recalls a controversial First Amendment case – still a landmark in the history of free expression after more than 30 years
History Lessons
Authors: Hasan Usama
Published: August 2008

Anyone seeking to combat extremism today must examine Islam’s past and learn from the example of its early leaders, says Usama Hasan
The Grand Illusion
Authors: Jian Ma , Drew Flora
Published: August 2008

Decades of control have killed independent thought in China, says Ma Jian
Regardless of Frontiers
Authors: Grayling AC
Published: August 2008

Freedom of speech is the most precious of human rights – it’s what gives us the chance of being fully human, says AC Grayling
Helium cryostat synchrotron charge densities determined using a large CCD detector – the upgraded beamline D3 at DESY
Authors: Morgenroth Wolfgang , Overgaard Jacob , Clausen Henrik F. , Svendsen Helle , Jørgensen Mads R. V. , Larsen Finn K. , Iversen Bo B.
Published: August 2008

A 165 mm Mar CCD detector has been fitted on a large Huber four-circle diffractometer together with a helium cryostat at beamline D3 at Hasylab, DESY in Hamburg. This setup allows fast collection of accurate, short-wavelength, very low temperature X-ray diffraction data for charge-density analysis. As a test example, diffraction data have been collected in 10 h on a hydrogen-bonded network system with 15 unique atoms, and the electron density was modelled with the multipole formalism in an X–N procedure using matching-temperature neutron diffraction data collected at Institut Laue Langevin, Grenoble in France.
Control of the rate of evaporation in protein crystallization by the `microbatch under oil' method
Authors: Brumshtein Boris , Greenblatt Harry M. , Futerman Anthony H. , Silman Israel , Sussman Joel L.
Published: August 2008

Microbatch crystallization under oil is a powerful procedure for obtaining protein crystals. Using this method, aqueous protein solutions are dispensed under liquid oil, and water evaporates through the layer of oil, with a concomitant increase in the concentrations of both protein and precipitant until the nucleation point is reached. A technique is presented for regulating the rate of water evaporation, which permits fine tuning of the crystallization conditions as well as preventing complete desiccation of the drops in the microbatch crystallization trays.
Birefringence images of micropipes viewed end-on in 6H-SiC single crystals
Authors: Ning Lina , Hu Xiaobo , Xu Xiangang , Chen Xiufang , Wang Yingmin , Jiang Shouzhen , Li Juan
Published: August 2008

The nature of the micropipe, a fatal defect in SiC-based device applications, is still not fully understood. In this work, the birefringence images of micropipes in 6H-SiC crystals along thecaxis have been observed and simulated in detail. Based on Frank's theory, the intensity contours of birefringence images for micropipes viewed end-on in 6H-SiC crystals have been derived by considering the photoelastic anisotropy of silicon carbide. The results are in good agreement with experimental observations.
2,9-Bis(1,3-benzothiazol-2-yl)-1,10-phenanthroline dichloromethane disolvate
Authors: Akther Jesmin , Lindeman Sergey , Karim Mohammad Rezaul
Published: August 2008

In the title compound, C26H14N4S2·2CH2Cl2, the two pendant benzothiazole groups are slightly twisted with respect to the phenanthroline core [dihedral angles = 1.03 (7) and 9.05 (5)°]. Weak intermolecular C—H...N and C—H...Cl interactions occur in the crystal structure.