bluuebunny/crossref_metadata_2025 huggingface dataset:
Femoroacetabular impingement after slipped upper femoral epiphysis
Authors: Wensaas A. , Gunderson R. B. , Svenningsen S. , Terjesen T.
Published: October 2012

Deformity after slipped upper femoral epiphysis (SUFE) can cause cam-type femoroacetabular impingement (FAI) and subsequent osteoarthritis (OA). However, there is little information regarding the radiological assessment and clinical consequences at long-term follow-up. We reviewed 36 patients (43 hips) previously treated by in situ fixation for SUFE with a mean follow-up of 37 years (21 to 50). Three observers measured the femoral head ratio (FHR), lateral femoral head ratio (LFHR), α-angle on anteroposterior (AP) and frog-leg lateral views, and anterior femoral head–neck offset ratio (OSR). A Harris hip score < 85 and/or radiologically diagnosed osteoarthritis (OA) was classified as a poor outcome. Patients with SUFE had significantly higher FHR, LFHR and α-angles and lower OSR than a control group of 22 subjects (35 hips) with radiologically normal hips. The interobserver agreement was less, with wider limits of agreement (LOA), in hips with previous SUFE than the control group. At long-term follow-up abnormal α-angles correlated with poor outcome, whereas FHR, LFHR and OSR did not.

We conclude that persistent deformity with radiological cam FAI after SUFE is associated with poorer clinical and radiological long-term outcome. Although the radiological measurements had quite wide limits of agreement, they are useful for the diagnosis of post-slip deformities in clinical practice.
Is cauda equina syndrome linked with obesity?
Authors: Venkatesan M. , Uzoigwe C. E. , Perianayagam G. , Braybrooke J. R. , Newey M. L.
Published: October 2012

No previous studies have examined the physical characteristics of patients with cauda equina syndrome (CES). We compared the anthropometric features of patients who developed CES after a disc prolapse with those who did not but who had symptoms that required elective surgery. We recorded the age, gender, height, weight and body mass index (BMI) of 92 consecutive patients who underwent elective lumbar discectomy and 40 consecutive patients who underwent discectomy for CES. On univariate analysis, the mean BMI of the elective discectomy cohort (26.5 kg/m2 (16.6 to 41.7) was very similar to that of the age-matched national mean (27.6 kg/m2, p = 1.0). However, the mean BMI of the CES cohort (31.1 kg/m2 (21.0 to 54.9)) was significantly higher than both that of the elective group (p < 0.001) and the age-matched national mean (p < 0.001). A similar pattern was seen with the weight of the groups. Multivariate logistic regression analysis was performed, adjusted for age, gender, height, weight and BMI. Increasing BMI and weight were strongly associated with an increased risk of CES (odds ratio (OR) 1.17, p < 0.001; and OR 1.06, p <  0.001, respectively). However, increasing height was linked with a reduced risk of CES (OR 0.9, p < 0.01). The odds of developing CES were 3.7 times higher (95% confidence interval (CI) 1.2 to 7.8, p = 0.016) in the overweight and obese (as defined by the World Health Organization: BMI ≥ 25 kg/m2) than in those of ideal weight. Those with very large discs (obstructing > 75% of the spinal canal) had a larger BMI than those with small discs (obstructing < 25% of the canal; p < 0.01). We therefore conclude that increasing BMI is associated with CES.
Comparison of the outcome following the fixation of osteotomies or fractures associated with total hip replacement using cables or wires
Authors: Berton C. , Puskas G. J. , Christofilopoulos P. , Stern R. , Hoffmeyer P. , Lübbeke A.
Published: October 2012

There are no recent studies comparing cable with wire for the fixation of osteotomies or fractures in total hip replacement (THR). Our objective was to evaluate the five-year clinical and radiological outcomes and complication rates of the two techniques. We undertook a review including all primary and revision THRs performed in one hospital between 1996 and 2005 using cable or wire fixation. Clinical and radiological evaluation was performed five years post-operatively. Cables were used in 51 THRs and wires in 126, and of these, 36 THRs with cable (71%) and 101 with wire (80%) were evaluated at follow-up. The five-year radiographs available for 33 cable and 91 wire THRs revealed rates of breakage of fixation of 12 of 33 (36%) and 42 of 91 (46%), respectively. With cable there was a significantly higher risk of metal debris (68% vs 9%; adjusted relative risk (RR) 6.6; 95% confidence interval (CI) 3.0 to 14.1), nonunion (36% vs 21%; adjusted RR 2.0; 95% CI 1.0 to 3.9) and osteolysis around the material, acetabulum or femur (61% vs 19%; adjusted RR 3.9; 95% CI 2.3 to 6.5). Cable breakage increased the risk of osteolysis to 83%. There was a trend towards foreign-body reaction and increased infection with cables. Clinical results did not differ between the groups.

In conclusion, we found a higher incidence of complications and a trend towards increased infection and foreign-body reaction with the use of cables.
Patient and implant survival following 4323 total hip replacements for acute femoral neck fracture
Authors: Jameson S. S. , Kyle J. , Baker P. N. , Mason J. , Deehan D. J. , McMurtry I. A. , Reed M. R.
Published: October 2012

United Kingdom National Institute for Health and Clinical Excellence guidelines recommend the use of total hip replacement (THR) for displaced intracapsular fractures of the femoral neck in cognitively intact patients, who were independently mobile prior to the injury. This study aimed to analyse the risk factors associated with revision of the implant and mortality following THR, and to quantify risk. National Joint Registry data recording a THR performed for acute fracture of the femoral neck between 2003 and 2010 were analysed. Cox proportional hazards models were used to investigate the extent to which risk of revision was related to specific covariates. Multivariable logistic regression was used to analyse factors affecting peri-operative mortality (< 90 days). A total of 4323 procedures were studied. There were 80 patients who had undergone revision surgery at the time of censoring (five-year revision rate 3.25%, 95% confidence interval 2.44 to 4.07) and 137 patients (3.2%) patients died within 90 days. After adjusting for patient and surgeon characteristics, an increased risk of revision was associated with the use of cementless prostheses compared with cemented (hazard ratio (HR) 1.33, p = 0.021). Revision was independent of bearing surface and head size. The risk of mortality within 90 days was significantly increased with higher American Society of Anesthesiologists (ASA) grade (grade 3: odds ratio (OR) 4.04, p < 0.001; grade 4/5: OR 20.26, p < 0.001; both compared with grades 1/2) and older age (≥ 75 years: OR 1.65, p = 0.025), but reduced over the study period (9% relative risk reduction per year).

THR is a good option in patients aged < 75 years and with ASA 1/2. Cementation of the femoral component does not adversely affect peri-operative mortality but improves survival of the implant in the mid-term when compared with cementless femoral components. There are no benefits of using head sizes > 28 mm or bearings other than metal-on-polyethylene. More research is required to determine the benefits of THR over hemiarthroplasty in older patients and those with ASA grades > 2.
Is patient reporting of physical function accurate following total knee replacement?
Authors: Hamilton D. F. , Gaston P. , Simpson A. H. R. W.
Published: October 2012

The aim of this study was to determine the association between the Oxford knee score (OKS) and direct assessment of outcome, and to examine how this relationship varied at different time-points following total knee replacement (TKR). Prospective data consisting of the OKS, numerical rating scales for ‘worst pain’ and ‘perceived mean daily pain’, timed functional assessments (chair rising, stairs and walking ability), goniometry and lower limb power were recorded for 183 patients pre-operatively and at six, 26 and 52 weeks post-operatively. The OKS was influenced primarily by the patient’s level of pain rather than objective functional assessments. The relationship between report of outcome and direct assessment changed over time: R2 = 35% pre-operatively, 44% at six weeks, 57% at 26 weeks and 62% at 52 weeks.

The relationship between assessment of performance and report of performance improved as the patient’s report of pain diminished, suggesting that patients’ reporting of functional outcome after TKR is influenced more by their pain level than their ability to accomplish tasks.
Promising one- to six-year results with the Motec wrist arthroplasty in patients with post-traumatic osteoarthritis
Authors: Reigstad O. , Lütken T. , Grimsgaard C. , Bolstad B. , Thorkildsen R. , Røkkum M.
Published: October 2012

The Motec cementless modular metal-on-metal ball-and-socket wrist arthroplasty was implanted in 16 wrists with scaphoid nonunion advanced collapse (SNAC; grades 3 or 4) and 14 wrists with scapholunate advanced collapse (SLAC) in 30 patients (20 men) with severe (grades 3 or 4) post-traumatic osteoarthritis of the wrist. The mean age of the patients was 52 years (31 to 71). All prostheses integrated well radiologically. At a mean follow-up of 3.2 years (1.1 to 6.1) no luxation or implant breakage occurred. Two wrists were converted to an arthrodesis for persistent pain. Loosening occurred in one further wrist at five years post-operatively. The remainder demonstrated close bone–implant contact. The clinical results were good, with markedly decreased Disabilities of the Arm Shoulder and Hand (DASH) and pain scores, and increased movement and grip strength. No patient used analgesics and most had returned to work.

Good short-term function was achieved using this wrist arthroplasty in a high-demand group of patients with post-traumatic osteoarthritis.
The Importance of Being At-Home: A Defense of Historic Preservation in Algeria
Authors: Wylie Diana
Published: October 2012

The entire French city of Oran, Algeria, had to be adapted to the needs of a new population when Algeria won its independence in 1962. A similar problem emerged in the 1990s when the city was flooded by rural refugees fleeing the war between government and Islamist forces. Ten years ago Bel Horizon, a historic preservation movement, was founded in Oran; its objective was not only to preserve Ottoman, Spanish, and French buildings, but also to foster the habits and attitudes of citizenship, especially in young people. Bel Horizon's goals and successes are at once modest and profound. This case study suggests that historic preservation movements do not simply serve the purposes of cultural and political nationalism, as Rem Koolhaas and others have recently argued. Rather, it suggests that associations like Bel Horizon can help people to accept cultural mixture as part of their heritage.
Adaptation as a Model for New Architecture in Historic Settings: Some Observations from Rome
Authors: Semes Steven W.
Published: October 2012

For centuries, many European cities and towns managed to accommodate growth and change while sustaining the historic character that, in modern times, has brought them recognition as cultural resources of high artistic value. All living organisms, too, must negotiate the competing claims of constancy and change through processes of adaptation that have long been the subject of scientific investigation. Recent developments in urban theory advocate the conscious application of similarly adaptive strategies for maintaining balance between necessary change and the conservation of historic character in the built environment. Rome, with its millennia of construction, alteration, demolition, and rebuilding, offers the clearest example of how different kinds of change—both adaptive and catastrophic—impact the city over time. After a half-century or more of architecture and urbanism that departed from traditional practice and privileged contrast with preexisting conditions over formal continuity, historic centers have come under a new threat. The idea of adaptation offers an alternative that redefines urban conservation practices in the interest of sustaining historic character over the long term, while permitting necessary growth and change.
“From the New World to the Old, and Back Again”: Whig University Leaders and Trans-Atlantic Nationalism in the Era of 1848
Authors: Ingrassia Brian M.
Published: October 2012

In the mid-1800s, university educators Henry Tappan (Michigan) and Francis Wayland (Brown) argued that higher education could serve as an internal improvement that would help build America’s national culture. Such a nationalistic view of university education dated back to the founding generation, yet the vision of thinkers like Tappan and Wayland was profoundly influenced by mid-century Whig political ideology, as well as their own transatlantic voyages. These intellectuals saw national growth as developing in time rather than in space, and thought that universities could help tie the nation together in an era of western expansion and political fragmentation. On the one hand, Tappan and Wayland admired European universities for their concentration of library resources and intellect, but on the other hand, they were less enamored with the politics these cultural institutions supported. Such thinkers wanted to create universities that would allow the United States to compete with Europe, while at the same time protecting the New World from the extremes of monarchy and revolution—the tendency to continually begin the world all over again—that characterized the 1848-era “Old World.” This article shows that historians of mid-century higher education have focused too narrowly on mid-century German-style reforms at the expense of the larger contexts of transatlantic nationalism and Whig ideology. While Tappan’s and Wayland’s intended reforms—especially Brown’s failed “New System”—did not succeed as well as they had planned, they did represent Whig thought regarding education in an era when social turmoil rocked peoples on both sides of the Atlantic.
“A Dangerous Set of People”: British Captives and the Making of Revolutionary Identity in the Mid-Atlantic Interior
Authors: Miller Ken
Published: October 2012

During fall 1775, American forces captured nearly seven hundred British soldiers manning forts near Montreal. The surrender of the British garrisons posed a problem for the new Continental Congress. Complicating matters for Whigs, their prisoners were fellow Britons seized in an unlawful insurgency. In late 1775, the colonies had yet to declare their independence and reconciliation with Britain remained the hope of many Americans. Mindful of their shared British heritage, officials on both sides continued to situate their opponents within a collective imperial identity. This sense of common kinship informed Continental officials’ approach to their British captives, as they pursued a policy intended to promote kindred relations between the prisoners and their local hosts. Congress dispatched most of the captives to Lancaster, Pennsylvania, an ethnically diverse and provincially oriented hinterland community safely isolated from military operations.

By mid-1776, Pennsylvania’s diversity, the escalating hostilities, and the mounting antagonisms between the insurgents and their prisoners complicated Continental policy. In Lancaster, English and German speakers’ tense encounters with their captives facilitated the break with Britain and nurtured an emerging Revolutionary identity. As the captives defied their hosts and cultivated subversive associations, locals policed the community. The new dangers encouraged local militants to transcend their cultural differences as they distinguished themselves from their enemies and found support in the company of fellow patriots. But the prisoners also exposed the boundaries of locals’ patriotism by revealing competing communal and Continental agendas. Local pressures helped redefine Continental perceptions of the British and transform American prisoner policy.
“From a Nation of Drunkards, We Have Become a Sober People”: The Wyandot Experience in the Ohio Valley during the Early Republic
Authors: Bontrager Shannon
Published: October 2012

In recent years scholars have emphasized how borderlands and the transition to borders have influenced politics. Where does collective memory fit into the politics of these boundaries? How did Native Americans remember borderlands as they attempted to deal with the rigid restrictions that Americans attempted to place around them? What was the relationship between race and borderlands and how does the act of remembering provoke this relationship? Evangelical Christians contributed to a new way for Americans to carve out national borders; they understood the frontier as spaces destined not for “primitive” Native Americans but for Anglo-Saxon and Christian dominance. But Wyandot Indians proactively made a new geography by utilizing astute cultural and political strategies based on their collective memory of diaspora and hybridity to mark out their own borders and control their own destiny in the face of American expansion. Evangelical missionary James Finley’s History of the Wyandot Mission at Upper Sandusky, Ohio provided an early depiction of this Wyandot agency despite his intentions to convert “the heathen.” Although written with significant prejudice, deconstructing Finley’s text exposes the collective memory that the Wyandot used as agency to create a completely new version of Christianity that stymied empire rather than empowered it. This paper will deconstruct and de-mythologize Finley’s account and utilize it as a case study to examine how Christian and non-Christian Wyandot remembrances of borderlands were used successfully in building Wyandot borders conceived of and implemented by Wyandot leaders of which American settlers and U.S. government officials could neither penetrate nor dismantle.
The Logic of the History of Ideas : Mark Bevir and Michael Oakeshott
Authors: Thompson Martyn P.
Published: October 2012

This essay criticizes Bevir’s account of the logic of the history of ideas by comparing it with Oakeshott’s account of the logic of historical enquiry. It concludes that Bevir’s account is deficient in two main respects. First, his account neglects to identify the logical status of the historical pasts which historians create. Second, his account is guided by a misleading conception of the relationship between philosophical analysis and historical practice.
A Moderate Logic of the History of Ideas
Authors: Martinich A. P.
Published: October 2012

Mark Bevir’s impressive theory of the logic of the history of ideas continues to attract readers and to irritate many theorists. This article has two purposes. One is to present the modified version, in which the focus will be on some major elements of Bevir’s theory. The concepts that he introduced from analytic philosophy did not always fit perfectly with the ones used from continental philosophy. In contrast with those critics who think that his borrowings from analytic philosophy damage his theory, I think that it will benefit by adding more. The other purpose of this article is to answer some of the most prominent criticisms of Bevir’s theory.
Thomist Scholarship and Plagiarism in the Early Enlightenment: Jacques Echard Reads the Speculum morale , Attributed to Vincent of Beauvais
Authors: Zahora Tomas
Published: October 2012

Vincent of Beauvais (c. 1190–1264) belongs among the most important medieval encyclopedists. Around 1300, an anonymous author using Vincent’s name compiled Speculum morale, a moral encyclopedia drawing, without acknowledgment, on Aquinas’s Summa Theologiae. In 1708 the French Dominican scholar Jacques Echard set out to resolve the ambiguities of the Speculum Morale in a work that is a fascinating window into the understanding of textual authority and plagiarism. As this article argues, Echard’s solution reflects textual-analytical principles as much as Thomist politics at whose intersection appears a modified understanding of plagiarism dependent on the privileged textual position of the Summa.
The Logic of the Historian and the Logic of the Citizen
Authors: Ron Amit
Published: October 2012

In the works that follow The Logic of the History of Ideas, Mark Bevir develops a post-foundational, participatory, and deliberative conception of democracy. This article examines the relationship between Bevir’s logic of the history of ideas and his logic of democratic deliberations. I argue that, given Bevir’s own framework, the logic of the concepts that are employed by historians can and should be vindicated through the logic of democratic deliberations. In this understanding, historical meanings are not objects that are analytically prior to the narrative in which they are embedded. They form an integral part of the narrative itself.
Post-Analytic Historicism
Authors: Bevir Mark
Published: October 2012

In this essay I reply to five friendly critics of my book The Logic of the History of Ideas—Martyn P. Thompson, Al P. Martinich, Sara R. Jordan, Amit Ron, and Daniel O’Neill. I want to comment on their amendments and extensions to my arguments, but also to suggest my ideas may have rougher edges than they recognize. The Logic described and defended a post-analytic historicism. As a historicist, I argued that human life was ineluctably historical, so explanations of ideas, texts, actions, and practices should rely on historical narratives, not appeals to formal classifications, correlations, systems, or models. As a post-analytic philosopher, I thought of my task as clarifying the implications of our concepts for historical reasoning.
Spectral Readings
Authors: Sofer Andrew
Published: October 2012

By enlisting material objects in the service of ideology critique, materialist criticism tends to dematerialize solid objects whose historical trajectories have been lost to performed memory ( kinamnesia ). A diachronic reading of Richard II ’s crown models how materialist criticism can reconstruct the ways that mobile physical objects set unstable, politicized meanings in motion at different levels of analysis. In addition to such elusive material stuff, theatre is made up of dark matter: an invisible dimension that evades detection, even though its effects are palpable in performance. Macbeth’s dagger is not there onstage, but it is not not there either. Dark matter resists semiotic and materialist analysis because it sheds no visible light. Detecting dark matter—offstage spaces and actions; absent characters; the narrated past; hallucination; blindness; obscenity; godhead; and so on—invites a new approach known as spectral reading. Both visible and dark objects matter in performance, but they matter in ways that demand distinct critical vocabularies.
Objects of Realism: Bertolt Brecht, Roland Barthes, and Marsha Norman
Authors: Begley Varun
Published: October 2012

This essay argues the need to rethink the straw man of dramatic realism as a pure embodiment of bourgeois/patriarchal ideology. Even in early, canonical works, such as Strindberg’s Miss Julie and Glaspell’s Trifles , we find contradictory attitudes toward material reality, attitudes observable in the use of props. While many critics have claimed that realism is a static form that ratifies the status quo, the fixations surrounding realist props may suggest struggle and transformation. The essay tests this hypothesis on Marsha Norman’s hyper-realist play ’night, Mother , which has polarized politically minded critics since its premiere. Examined from the perspective of props, the play’s apparently suffocating realism discloses a counter-economy of craft and appropriation.
Human Remains: Acting, Objects, and Belief in Performance
Authors: Monks Aoife
Published: October 2012

The image of an actor holding a skull is the extraordinarily powerful, even iconic image that often stands in for acting itself. This essay argues that the interaction between actors and human remains onstage illuminates the uncanny relationship between acting and stage objects, revealing to us the strangeness of things onstage and the peculiarities of acting itself. The essay examines a range of strategies employed by actors to harness and contain the disruptive powers of human remains. It begins by looking at how remains might be imagined through Stanislavski’s complex and often contradictory approach to objects in performance, and argues that their use onstage resembles that of religious relics. The essay considers the ways in which communion with objects might facilitate and displace virtuosity in acting. It then examines how Ron Vawter controlled the power of the cremated ashes that he used in his 1992 performance Roy Cohn/Jack Smith by making all of his theatrical strategies public—apart from his use of human remains. These examples help to investigate how the language of possession, the anamorphic powers of relics, and the struggles over authority and agency in performance feature in the imagined role that human remains play in producing acting. It argues, furthermore, that the abject qualities of relics may function as powerful and disturbing metaphors for the process of acting itself, by underscoring the loss of self that the actor must undergo in order to act.
Material Remains at Play
Authors: Hodgdon Barbara
Published: October 2012

This essay meditates critically on the promptbook (or prompt script ), as well as other archival documents (dresser’s notes, photographs, fight scripts, rehearsal notes), analyzing their form and function as they reveal traces of actors’ bodies in relation to time and space. The essay’s interest is in articulating a methodology for mapping the roles such material remains play in performance culture. Rather than attempting to reconstruct the (disappeared) performance, it rethinks and positions such “leftovers” not as giving indexical access to a theatrical past and thus bound up with ontology, neither archival nor documentary, but as sites of re-performance. Two especially rich promptscripts—those for Peter Brook’s 1978 Antony and Cleopatra (Royal Shakespeare Company) and Richard Eyre’s 1990 Richard III (National Theatre)—situate this work-inprogress, a kind of performative (re)writing that not only reenacts, but also reimagines, or replays anew, the force of performance processes.
Recovery of Boron from the Clay Waste of Boron Industry by Leaching
Authors: Kıpçak İlker , Özdemir Mine
Published: October 2012

In this study, the recovery of boron from the clay waste of boron industry by leaching with sulfuric acid solution was studied in a batch reactor and the subsequent production of boric acid (H3BO3) was investigated. The effects of acid concentration, solid-to-liquid ratio and reaction temperature on the leaching process were examined. Experimental studies were carried out in the ranges of 0.1-1.0 M for acid concentration, 1-10 g/120 mL for solid-to-liquid ratio and 25-75°C for reaction temperature. The analysis of the experimental data showed that the kinetics of the leaching process fitted the Avrami model in the form of X = 1 – exp (–k t n). For the production of boric acid, the optimum leaching conditions were determined as follows: acid concentration, 0.1 M; solid-to-liquid ratio, 6 g/120 mL; reaction temperature, 50°C and reaction time, 60 min. Finally, boric acid was produced in the purity of more than 95% by crystallization of the leach solution.
Investigating the particle dispersion in a spout-fluid bed using particle trajectory
Authors: Zhang Yong , Zhong Wenqi , Jin Baosheng , Xiao Rui
Published: October 2012

Particle dispersion in a spout-fluid bed was investigated using time series of particle trajectory by evaluation of dispersion coefficient based on Einstein’s expression. A series of experiments were performed in a lab-scale spout-fluid bed using microwave heating and infrared thermal imaging (MH-ITI) technique for recording the position of a tracer. The influence of gas velocity on the particle dispersion in different flow regimes has been taken into account. The results show that the particle dispersion behavior depends on the flow regime. In the flow regime of internal jet, the increase of gas velocity improves the axial dispersion. In the case of jet in fluidized bed with bubbling, increasing fluidizing gas velocity promotes the radial dispersion at the lower part of bed and the axial dispersion at the upper part of bed. In the flow regime of jet in fluidized bed with slugging, the effect of fluidizing gas is related to the slug pattern. The result also indicates that the transition of flow regime can be evaluated from the particle trajectory.
Analyzing Genetic Association Studies with an Extended Propensity Score Approach
Authors: Zhao Huaqing , Rebbeck Timothy R. , Mitra Nandita
Published: October 2012

Propensity scores are commonly used to address confounding in observational studies. However, they have not been previously adapted to deal with bias in genetic association studies. We propose an extension of our previous method (Zhao et al., 2009) that uses a multilevel propensity score approach and allows one to estimate the effect of a genotype under an additive model and also simultaneously adjusts for confounders such as genetic ancestry and patient and disease characteristics. Using simulation studies, we demonstrate that this extended genetic propensity score (eGPS) can adequately adjust and consistently correct for bias due to confounding in a variety of circumstances. Under all simulation scenarios, the eGPS method yields estimates with bias close to 0 (mean=0.018, standard error=0.01). Our method also preserves statistical properties such as coverage probability, Type I error, and power. We illustrate this approach in a population-based genetic association study of testicular germ cell tumors and KITLG and SPRY4 susceptibility genes. We conclude that our method provides a novel and broadly applicable analytic strategy for obtaining less biased and more valid estimates of genetic associations.
Grass is Always Greener When It's Legal: Policies for State Regulated Marijuana
Authors: Cohen Evan , McGowan Richard
Published: October 2012

With marijuana legalization currently on three state ballots this year, it is vital to consider optimal marijuana regulatory and tax structures. This paper lays out a framework for a regulated marijuana market, drawing on the lessons from the taxation and regulation of similar products.
Firms' Investment under Financial and Infrastructure Constraints: Evidence from In-House Generation in Sub-Saharan Africa
Authors: Steinbuks Jevgenijs
Published: October 2012

While it is well known that financing and infrastructure constraints negatively affect economic development, the correlations between these constraints have been underexplored in the economics literature. This paper focuses on the implications of financing and infrastructure constraints by studying firms’ investments in electric generators as a response to public power interruptions. A theoretical model demonstrates that financial constraints lower economic returns on owning electric generators, making firms less likely to install private generators if the public power supply becomes unreliable. The empirical results show that, controlling for other factors, firms with a lower cost of external financing are more likely to own private generators in areas where the public power supply is less reliable. Observed correlations among reliability of power supply, financial constraints, and investment in electric generators thus appear consistent with the hypothesis that underdeveloped financial markets and inadequate infrastructure can be a greater barrier for economic development than either of these constraints separately.
Dynamics of bioenergetic microcompartments
Authors: Busch Karin B. , Deckers-Hebestreit Gabriele , Hanke Guy T. , Mulkidjanian Armen Y.
Published: October 2012

The vast majority of life on earth is dependent on harvesting electrochemical potentials over membranes for the synthesis of ATP. Generation of membrane potential often relies on electron transport through membrane protein complexes, which vary among the bioenergetic membranes found in living organisms. In order to maximize the efficient harvesting of the electrochemical potential, energy loss must be minimized, and this is achieved partly by restricting certain events to specific microcompartments, on bioenergetic membranes. In this review we will describe the characteristics of the energy-converting supramolecular structures involved in oxidative phosphorylation in mitochondria and bacteria, and photophosphorylation. Efficient function of electron transfer pathways requires regulation of electron flow, and we will also discuss how this is partly achieved through dynamic re-compartmentation of the membrane complexes into different supercomplexes. In addition to supercomplexes, the supramolecular structure of the membrane, and in particular the role of water layers on the surface of the membrane in the prevention of wasteful proton escape (and therefore energy loss), is discussed in detail. In summary, the restriction of energetic processes to specific microcompartments on bioenergetic membranes minimizes energy loss, and dynamic rearrangement of these structures allows for regulation.
The biosynthesis of caprazamycins and related liponucleoside antibiotics: new insights
Authors: Gust Bertolt , Eitel Kornelia , Tang Xiaoyu
Published: October 2012

The first step in the membrane cycle of reactions during peptidoglycan biosynthesis is the transfer of phospho-MurNAc-pentapeptide from UDP-MurNAc-pentapeptide to undecaprenyl phosphate, catalyzed by the integral membrane protein MraY translocase. Different MraY inhibitors are known and can be subdivided into classes depending on their structural composition. Caprazamycins belong to the liponucleoside class of antibiotics isolated from Streptomyces sp. MK730-62F2. They possess activity in vitro against Gram-positive bacteria, in particular against the genus Mycobacterium including Mycobacterium intracellulare, Mycobacterium avium and Mycobacterium tuberculosis. Caprazamycins and the structurally related liposidomycins and A-90289 share a unique composition of moieties. Their complex structure is derived from 5′-(β-O-aminoribosyl)-glycyluridine and comprises a unique N,N′-dimethyldiazepanone ring. Recently, the corresponding biosynthetic gene clusters of caprazamycins, liposidomycins and A-90289 have been discovered and will be compared in this review. New information is also emerging regarding the biosynthesis of liponucleoside antibiotics obtained by gene disruption experiments and biochemical investigations.
Reorientational Dynamics of Organophosphate Glass Formers – a Joint Study by 31P NMR, Dielectric Spectroscopy and Light Scattering
Authors: Adishchev Sergey , Bock Daniel , Gainaru Catalin , Kahlau Robert , Micko Björn , Petzold Nikolaus , Pötzschner Björn , Rössler Ernst A.
Published: October 2012

We study molecular reorientation in the glass formers triethyl-, tripropyl-, and m-tricresyl phosphate by measuring 31P NMR spectra, relaxation (T
1 and T
2), stimulated echo decays and two-dimensional spectra over a large temperature range (130–370 K). The results are compared to those from dielectric spectroscopy (DS) and depolarized light scattering (LS). While the time constants τ

α
of the primary (α-) process in the range  × 10−11–100 s well agree, the stretching of the reorientational correlation function is probe dependent, i.e., the rank-two functions (NMR and LS) essentially agree whereas the rank-one function (DS) is less stretched. The very similar 2D spectra recorded as a function of mixing time demonstrate that the reorientational mechanism does not significantly vary among the super-cooled liquids. A model of combining large- and small-angle reorientation allows for reproducing the 2D spectra and may be taken as generic for the dynamics in viscous molecular liquids. Pronounced secondary (β-) processes do not only effect the NMR relaxation but can be identified directly in the time domain by the stimulated echo technique. This becomes possible due to its broad time window (10 μs–100 s). Thus, applying the different 1D and 2D techniques makes 31P NMR well suited to probe molecular reorientation over a wide dynamic range.
1H NMR T
1 Relaxation of Polymer/Montmorillonite Nanocomposites with Different Clay Contents and Degrees of Exfoliation: Magnetic Field Effects
Authors: Xu Bo , Leisen Johannes , Boehme Ute , Scheler Ulrich , Beckham Haskell W.
Published: October 2012

The initial stage of the NMR 1H T
1 relaxation of well-defined polypropylene-montmorillonite nanocomposites was investigated at two different magnetic fields of 0.54 and 7.05 T. At 0.54 T, two periods can be distinguished during the first 30 ms after a saturation pulse train. Both periods scale linearly with the square root of the recovery time. The first period occurs during the first 1 ms and is attributed to direct dipolar relaxation of nuclei in immediate proximity to the clay. It is caused by paramagnetic impurities within the clay and is characterized by a magnetization recovery curve with a slope proportional to the concentration of these impurities. The second period occurs at 4 to 30 ms after saturation and is due to spin diffusion between the sink, formed by the initial relaxation at the clay surface, and the surrounding polymer matrix, which relaxes at a much slower rate. The second period is characterized by a magnetization recovery curve with a slope proportional to the effective surface area of the clay, from which a degree of exfoliation may be determined. At 7.05 T, only a single relaxation recovery period is observed. At this higher magnetic field, the direct relaxation is characterized by a substantially longer relaxation time so that it is not distinguished from the spin-diffusion process. As with the slope of the second period of the magnetization recovery at 0.54 T, the slope of the magnetization recovery curve at 7.05 T can be utilized to extract a degree of exfoliation.
Dynamical Line-Shifts in High-Field Electron Spin Resonance: Applications to Polymer Physics
Authors: Bercu Vasile , Martinelli Massimo , Pardi Luca , Massa Carlo Andrea , Leporini Dino
Published: October 2012

High-field high-frequency Electron Paramagnetic Resonance spectroscopy (HF
2
-EPR) is a powerful tool to investigate, with ultra-high angular resolution, the rotational dynamics of complex systems like polymers, viscous fluids and glasses. Usually, information is drawn by detailed numerical analysis of the overall lineshape. Here, we present a simplified analytical model of the line shifts due to the rotational dynamics of the paramagnetic centre. The model captures the basic features of the reorientation process (time scale and size of the angular jump). It is compared with experimental results concerning the reorientation of a paramagnetic guest molecule dissolved in polystyrene. We find that, if the rotational model to describe the reorientation of the radical is consistent, the best-fit parameters yield equally acceptable best-fits of the overall spectrum by numerical simulations and dynamical line shifts by independent analytic expressions.
Multinuclear NMR Study of Zinc Dicyanide
Authors: Werner-Zwanziger Ulrike , Chapman Karena W. , Zwanziger Josef W.
Published: October 2012

The isotropic negative expansion of Zn(CN)2 has been linked to a temperature induced increase in off-axis tilting of the C–N bond direction and an increase in CN-bond length. However, the bond length could be determined only indirectly based on pair-distribution function analysis and was found to be surprisingly large. Here we study Zn(CN)2 by nuclear magnetic resonance spectroscopy and first principles calculations. By using samples enriched in
13
C and
15
N the dipole coupling between carbon and nitrogen is determined, and from this an upper bound on the C–N bond length of 1.19 ± 0.01 Å is derived. This quantity agrees with earlier determinations based on diffraction but is shorter than estimates based on pair distribution function analysis. The relation of this estimate to possible dynamics in the sample is discussed. Finally,
67
Zn NMR is used together with first principles calculations to assess disorder in the material.
Melting of Low Molecular Weight Compounds in Confinement Observed by2H-Solid State NMR: Biphenyl, a Case Study
Authors: de Sousa Amadeu Nader , Grünberg Bob , Frydel Jarek , Werner Mayke , Limbach Hans-Heinrich , Breitzke Hergen , Buntkowsky Gerd
Published: October 2012

The2H-NMR solid echo spectra of biphenyl molecules as guests in the mesopores of neat and silylated SBA-15 have been measured as a function of temperature. At low temperatures typical2H-Pake patterns with parameters of (Qzz=132 kHz, corresponding to Qcc=176 kHz) and (η=0.04) are observed. All samples exhibit a strong reduction of the melting point from the bulk value of 342.4 K to values between 222 K and 229 K, depending on both the pore diameter and the surface state and a glass like behavior of the biphenyl molecules in the melting regime. Employing the Roesslertwo-phase modelof the modeling of glass-transitions by2H-solid state NMR the distribution of activation energies for the rotational motions has been determined. At temperatures closely below the glass-transition temperature deviations from a static Pake pattern of an aromatic deuteron are observed, which indicate a pre-melting motion of biphenyl, which could be caused by C2-ring flips of the phenyl rings.
Kinetics of Coupled Double Proton and Deuteron Transfer in Hydrogen-Bonded Ribbons of Crystalline Pyrazole-4-carboxylic Acid
Authors: Torres Verónica , Lopez Juan-Miguel , Langer Uwe , Buntkowsky Gerd , Vieth Hans-Martin , Elguero José , Limbach Hans-Heinrich
Published: October 2012

The proton tautomerism of pyrazole-4-carboxylic acid (PCA) has been studied by a combination of 15N CPMAS and 2H NMR spectroscopy and relaxometry. Down to 250 K, PCA forms a hydrogen bonded ribbon where adjacent carboxylic and pyrazole groups are linked by an OH···N and an O···HN hydrogen bond, forming either the tautomeric state A or B. Down to about 250 K, the tautomerism is fast on the NMR timescale and degenerate, corresponding to a phase exhibiting dynamic proton disorder. At lower temperatures, a transition to an ordered phase is observed with localized protons, assigned to an all-syn conformation adopting the sequence of tautomeric states ..ABABA.. The longitudinal 15N relaxation times T
1 of PCA-15N2 have been measured at 9.12 MHz (2.1 T). Because of the low field, a chemical shift anisotropy mechanism could be neglected, and the data were analyzed in terms of a dipolar 1H-15N relaxation mechanism, yielding the rate constants k
HH. The rate constants k
HD and k
DD were obtained from the measurement and analysis of the 2H T
1 values of PCA-15N1-d0.9 and PCA-15N1-d0.1 measured at 46.03 MHz. Within the margin of error, no kinetic isotope effects could be detected, in contrast to previous results reported for the very fast tautomerism of solid benzoic acid dimers and the much slower tautomerism of solid 3,5-diphenyl-4-brompyrazole (DPBrP) dimers. The Arrhenius curves of all three systems were simulated using the Bell–Limbach tunneling model. Evidence for a major heavy atom motion for the tautomerism of PCA is obtained, associated with small angle reorientation of PCA molecules around the molecular axis. The observed proton order-disorder transition and the mechanism of the observed rate process are discussed in terms of a coupling of adjacent tautomeric states.
Transfer of Parahydrogen Induced Polarization in Scalar Coupled Systems at Variable Magnetic Field
Authors: Kiryutin Alexey S. , Ivanov Konstantin L. , Yurkovskaya Alexandra V. , Kaptein Robert , Vieth Hans-Martin
Published: October 2012

Para-Hydrogen Induced Polarization (PHIP) experiments were performed in coupled multispin systems at variable magnetic fields. We studied the magnetic field dependence of PHIP in styrene, which is the product of hydrogenation of phenylacetylene. At low magnetic fields where the spins are coupled strongly by scalar interaction efficient polarization transfer among the interacting protons takes place. The experimentally observed spectra are in good agreement with the simulation, which takes into account eight coupled spins. We also demonstrate effects of nuclear spin level anti-crossings on the PHIP pattern. It is shown that rapid passage through the level anti-crossing enables highly efficient polarization transfer between specific spin orders. In addition, we studied PHIP transfer to
13
C and
19
F hetero-nuclei. It is shown that hetero-nuclei can be efficiently polarized in a wide field range; in particular, for polarizing them it is not necessary to go to ultra-low fields, which provide their strong coupling to protons. The resulting polarization is of the multiplet type and gives strong enhancements of the individual NMR lines. In general, variation of the magnetic field gives the opportunity for manipulating PHIP patterns and transferring polarization to target spins of choice.
Concentration and Humidity Effect on Gelatin Films Studied by NMR
Authors: Ghoshal Sushanta , Mattea Carlos , Du Lijun , Stapf Siegfried
Published: October 2012

Gelatin films were prepared using different initial concentrations (1 to 30%) in H2O (w/v). The solid films were kept at four different environmental conditions at 20%, 43%, 75%, and 90% relative humidity, until complete equilibrium was achieved. Spin–spin relaxation (T
2) and spin–lattice relaxation (T
1) times of the samples were determined using a low-field nuclear magnetic resonance (NMR) spectrometer operated at 40 MHz proton (1H) Larmor frequency and were correlated with the molecular mobility of the system influenced by the humidity conditions and initial concentration. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed as well to investigate the thermal properties of the samples. The results indicate an increase in molecular mobility of the gelatin films with the increase of storage humidity independent of the initial concentration and suggest that the dynamic of the films depends on the amount of the water in the amorphous region of the film.
Deuteron Magnetic Resonance Studies of Anhydrous Caffeine
Authors: Nowaczyk Andre , Nath Ramesh Chandra , Zimmermann Herbert , Böhmer Roland
Published: October 2012

Methyl deuterated caffeine powder was studied using2H-NMR relaxometry and line shape analysis. In caffeine's low-temperature phase the spin-lattice relaxation times indicate a thermally activated CD3reorientation (activation energy ≈4 kJ/mol). Below theT1minimum near 35 K the quadrupolar echo spectra develop features indicative for quantum mechanical tunneling. Dielectric measurements indicate the presence of dipole moment fluctuations with times scales that follow an Arrhenius law (energy barrier ≈107 kJ/mol). It is argued that the underlying motion involves small-angle molecular excursions and therefore remains undetectedviastimulated-echo spectroscopy. The hysteresis accompanying the order/disorder transition taking place above 400 K was monitored using solid-echo line shapes as well asviaspin relaxation times. In the high-temperature phase indications for the onset of anisotropic large-angle motions were obtained.