Risk factors for recurrent falls in older adults: A systematic review with meta-analysis

Older adults who fall recurrently (i.e., 2 or more falls/year) are at risk of functional decline and mortality. Understanding which risk factors for recurrent falls are most important will inform secondary fall prevention strategies that can reduce recurrent falls risk. Thus, we conducted a systematic review with meta-analysis to determine the relative risk of recurrent falls for different types of falls risk factors. MEDLINE, EMBASE, PsycINFO, and CINAHL databases were searched on April 25, 2019 (Prospero Registration: CRD42019118888). We included peer-reviewed prospective studies which examined risk factors that contributed to recurrent falls in adults aged ≥ 60 years. Using the falls risk classification system of Lord and colleagues, we classified each risk factor into one of the following domains: 1) balance and mobility; 2) environmental; 3) psychological; 4) medical; 5) medication; 6) sensory and neuromuscular; or 7) sociodemographic. We calculated the summary relative risk (RR) for each domain and evaluated the risk of bias and quality of reporting. Twenty-two studies were included in this systematic review and meta-analysis. Four domains predicted recurrent falls: balance and mobility (RR:1.32;95 % CI:[1.10, 1.59]), medication (RR:1.53;95 % CI:[1.11, 2.10]), psychological (RR:1.35;95 % CI:[1.03, 1.78]), and sensory and neuromuscular (RR:1.51;95 % CI:[1.18, 1.92]). Each of these four domains can be viewed as a marker of frailty. The risk of bias was low, and the study quality was high (minimum:19/22). Older adults with markers of frailty are up to 53 % more likely to experience recurrent falls. Strategies that identify and resolve frailty markers should be a frontline approach to preventing recurrent falls.

Searches for Sterile Neutrinos with the IceCube Detector

The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous ν_{μ} or ν[over ¯]_{μ} disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin^{2}2θ_{24}≤0.02 at Δm^{2}∼0.3  eV^{2} at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of |U_{e4}|^{2}.

Cognitive status is a determinant of health resource utilization among individuals with a history of falls: a 12-month prospective cohort study

SUMMARY

Falls are a costly public health problem worldwide. The literature is devoid of prospective data that identifies factors among fallers that significantly drive health care resource utilization. We found that cognitive function--specifically, executive functions--and cognitive status are significant determinants of health resource utilization among older fallers.

INTRODUCTION

Although falls are costly, there are no prospective data examining factors among fallers that drive health care resource utilization. We identified key determinants of health resource utilization (HRU) at 6 and 12 months among older adults with a history of falls. Specifically, with the increasing recognition that cognitive impairment is associated with increased falls risk, we investigated cognition as a potential driver of health resource utilization.

METHODS

This 12-month prospective cohort study at the Vancouver Falls Prevention Clinic (n = 319) included participants with a history of at least one fall in the previous 12 months. Based on their cognitive status, participants were divided into two groups: (1) no mild cognitive impairment (MCI) and (2) MCI. We constructed two linear regression models with HRU at 6 and 12 months as the dependent variables for each model, respectively. Predictors relating to mobility, global cognition, executive functions, and cognitive status (MCI versus no MCI) were examined. Age, sex, comorbidities, depression status, and activities of daily living were included regardless of statistical significance.

RESULTS

Global cognition, comorbidities, working memory, and cognitive status (MCI versus no MCI ascertained using the Montreal Cognitive Assessment (MoCA)) were significant determinants of total HRU at 6 months. The number of medical comorbidities and global cognition were significant determinants of total HRU at 12 months.

CONCLUSION

MCI status was a determinant of HRU at 6 months among older adults with a history of falls. As such, efforts to minimize health care resource use related to falls, it is important to tailor future interventions to be effective for people with MCI who fall.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01022866.

Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19)  GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100  TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.

Observation of high-energy astrophysical neutrinos in three years of IceCube data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8)  GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

Simultaneous transitions in cuprate momentum-space topology and electronic symmetry breaking

The existence of electronic symmetry breaking in the underdoped cuprates and its disappearance with increased hole density p are now widely reported. However, the relation between this transition and the momentum-space (k-space) electronic structure underpinning the superconductivity has not yet been established. Here, we visualize the Q = 0 (intra-unit-cell) and Q ≠ 0 (density-wave) broken-symmetry states, simultaneously with the coherent k-space topology, for Bi₂Sr₂CaCu₂O(8+δ) samples spanning the phase diagram 0.06 ≤ p ≤ 0.23. We show that the electronic symmetry-breaking tendencies weaken with increasing p and disappear close to a critical doping p(c) = 0.19. Concomitantly, the coherent k-space topology undergoes an abrupt transition, from arcs to closed contours, at the same p(c). These data reveal that the k-space topology transformation in cuprates is linked intimately with the disappearance of the electronic symmetry breaking at a concealed critical point.

Evidence for high-energy extraterrestrial neutrinos at the IceCube detector

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to about 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the 28 events at the 4σ level. These 28 events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

Measurement of atmospheric neutrino oscillations with IceCube

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

First observation of PeV-energy neutrinos with IceCube

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

Measurement of the atmospheric νe flux in IceCube

We report the first measurement of the atmospheric electron neutrino flux in the energy range between approximately 80 GeV and 6 TeV, using data recorded during the first year of operation of IceCube's DeepCore low-energy extension. Techniques to identify neutrinos interacting within the DeepCore volume and veto muons originating outside the detector are demonstrated. A sample of 1029 events is observed in 281 days of data, of which 496±66(stat)±88(syst) are estimated to be cascade events, including both electron neutrino and neutral current events. The rest of the sample includes residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is consistent with models of atmospheric neutrinos in this energy range. This constitutes the first observation of electron neutrinos and neutral current interactions in a very large volume neutrino telescope optimized for the TeV energy range.

Search for dark matter annihilations in the sun with the 79-string IceCube detector

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000  GeV/c2. These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35  GeV/c2 for most WIMP models.

Examining the relationship between specific cognitive processes and falls risk in older adults: a systematic review

This systematic review aims to establish which cognitive domains are associated with falls or falls risk. Recent evidence suggests that impaired cognition increases seniors' risk of falling. The purpose of this review was to identify the cognitive domains that are significantly associated with falls or falls risk in older adults. We conducted a systematic review of peer-reviewed journal articles published from 1948 to present, focusing on studies investigating different domains of cognitive function and their association with falls or falls risk in adults aged 60 years or older. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we completed a comprehensive search of MEDLINE, PubMed, and EMBASE databases to identify studies examining the association between cognitive function and falls or falls risk. With an expert in the field, we developed a quality assessment questionnaire to rate the quality of the studies included in this systematic review. Twenty-five studies were included in the review. We categorized studies based on two related but distinct cognitive domains: (1) executive functions or (2) dual-task ability. Twelve studies reported a significant association between executive functions and falls risk. Thirteen studies reported that dual-task performance is a predictor of falls or falls risk in older adults. Three studies did not report an association between cognition and falls risk. Consistent evidence demonstrated that executive functions and dual-task performance were highly associated with falls or falls risk. The results from this review will aid healthcare professionals and researchers in developing innovative screening and treatment strategies for mitigating falls risk by targeting specific cognitive domains.

SF-6D and EQ-5D result in widely divergent incremental cost-effectiveness ratios in a clinical trial of older women: implications for health policy decisions

SUMMARY

Using two instruments (SF-6D and EQ-5D) to estimate quality adjusted life years (QALYs), we conducted an economic evaluation of a 12-month randomized controlled trial with a 12-month follow-up study in older women to evaluate the value for money of two doses of resistance training compared with balance and tone classes. We found that the incremental QALYs estimated from the SF-6D were two- to threefold greater than those estimated from the EQ-5D.

INTRODUCTION

Decision makers must continually choose between existing and new interventions. Hence, economic evaluations are increasingly prevalent. The impact of quality-adjusted life year (QALY) estimates using different instruments on the incremental cost-effectiveness ratios (ICERs) is not well understood in older adults. Thus, we compared ICERs, in older women, estimated by the EuroQol-5D (EQ-5D) and the Short Form-6D (SF-6D) to discuss implications on decision making.

METHODS

Using both the EQ-5D and the SF-6D, we compared the incremental cost per QALY gained in a randomized controlled trial of resistance training in 155 community-dwelling women aged 65 to 75 years. The 12-month randomized controlled trial included a subsequent 12-month follow-up. Our focus, the follow-up study, included 123 of the 155 participants from the Brain Power study; 98 took part in the economic evaluation (twice-weekly balance and tone exercises, n = 28; once-weekly resistance training, n = 35; twice-weekly resistance training, n = 35). Our primary outcome measure was the incremental cost per QALY gained of once- or twice-weekly resistance training compared with balance and tone exercises.

RESULTS

At cessation of the follow-up study, the incremental QALY was -0.051 (EQ-5D) and -0.144 (SF-6D) for the once-weekly resistance training group and -0.081 (EQ-5D) and -0.127 (SF-6D) for the twice-weekly resistance training group compared with balance and tone classes.

CONCLUSION

The incremental QALYs estimated from the SF-6D were two- to threefold greater than those estimated from the EQ-5D. Given the large magnitude of difference, the choice of preference-based utility instrument may substantially impact health care decisions.

Guidelines for conducting and reporting economic evaluation of fall prevention strategies

Falls in older people result in substantial health burden. Compelling evidence indicates that falls can be prevented. We developed comprehensive guidelines for economic evaluations of fall prevention interventions to facilitate publication of high-quality economic evaluations of the effective strategies and aid decision making.

INTRODUCTION

The importance of economics applied to falls and fall prevention in older people has largely been overlooked. The use of different methodologies to assess the costs and health benefits of the interventions and their comparators and the inconsistent reporting in the studies limits the usefulness of these economic evaluations for decision making. We developed guidelines to encourage and facilitate completion of high-quality economic evaluations of effective fall prevention strategies.

METHODS

We used a generic checklist for economic evaluations as a platform to develop comprehensive guidelines for conducting and reporting economic evaluations of fall prevention strategies. We considered the many challenges involved, particularly in identifying, measuring, and valuing the relevant cost items.

RESULTS

We recommend researchers include cost outcomes and report incremental cost-effectiveness ratios in terms of falls prevented and quality adjusted life years in all clinical trials of fall prevention interventions. Studies should include the following cost categories: (1) implementing the intervention, (2) delivering the comparator group intervention, (3) total health care costs, (4) costs of fall-related health care resource use, and (5) personal and informal carer opportunity costs.

CONCLUSIONS

This paper provides a timely benchmark to promote comparability and consistency for conducting and reporting economic evaluations of fall prevention strategies.

Does a home-based strength and balance programme in people aged > or =80 years provide the best value for money to prevent falls? A systematic review of economic evaluations of falls prevention interventions

OBJECTIVES

To investigate the value for money of strategies to prevent falls in older adults living in the community.

DESIGN

Systematic review of peer reviewed journal articles reporting an economic evaluation of a falls prevention intervention as part of a randomised controlled trial or a controlled trial, or using an analytical model. MEDLINE, PUBMED, EMBASE and NHS EED databases were searched to identify cost-effectiveness, cost-utility and cost-benefit studies from 1945 through July 2008.

MAIN OUTCOME MEASURES

The primary outcome measure was incremental cost-effectiveness, cost-utility and cost-benefit ratios in the reported currency and in pounds sterling at 2008 prices. The quality of the studies was assessed using two instruments: (1) an economic evaluation checklist developed by Drummond and colleagues and (2) the Quality of Health Economic Studies instrument.

RESULTS

Nine studies meeting our inclusion criteria included eight cost-effectiveness analyses, one cost-utility and one cost-benefit analysis. Three effective falls prevention strategies were cost saving in a subgroup of

PARTICIPANTS

(1) an individually customised multifactorial programme in those with four or more of the eight targeted fall risk factors, (2) the home-based Otago Exercise Programme in people > or =80 years and (3) a home safety programme in the subgroup with a previous fall. These three findings were from six studies that scored > or =75% on the Quality of Health Economic Studies instrument.

CONCLUSIONS

Best value for money came from effective single factor interventions such as the Otago Exercise Programme which was cost saving in adults 80 years and older. This programme has broad applicability thus warranting warrants health policy decision-makers' close scrutiny.

Limits on neutrino emission from gamma-ray bursts with the 40 string IceCube detector

IceCube has become the first neutrino telescope with a sensitivity below the TeV neutrino flux predicted from gamma-ray bursts if gamma-ray bursts are responsible for the observed cosmic-ray flux above 10(18)  eV. Two separate analyses using the half-complete IceCube detector, one a dedicated search for neutrinos from pγ interactions in the prompt phase of the gamma-ray burst fireball and the other a generic search for any neutrino emission from these sources over a wide range of energies and emission times, produced no evidence for neutrino emission, excluding prevailing models at 90% confidence.

Intra-unit-cell electronic nematicity of the high-T(c) copper-oxide pseudogap states

In the high-transition-temperature (high-T(c)) superconductors the pseudogap phase becomes predominant when the density of doped holes is reduced. Within this phase it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Here we report the determination of a quantitative order parameter representing intra-unit-cell nematicity: the breaking of rotational symmetry by the electronic structure within each CuO(2) unit cell. We analyse spectroscopic-imaging scanning tunnelling microscope images of the intra-unit-cell states in underdoped Bi(2)Sr(2)CaCu(2)O(8 +) (delta) and, using two independent evaluation techniques, find evidence for electronic nematicity of the states close to the pseudogap energy. Moreover, we demonstrate directly that these phenomena arise from electronic differences at the two oxygen sites within each unit cell. If the characteristics of the pseudogap seen here and by other techniques all have the same microscopic origin, this phase involves weak magnetic states at the O sites that break 90 degrees -rotational symmetry within every CuO(2) unit cell.

International comparison of cost of falls in older adults living in the community: a systematic review

SUMMARY

Our objective was to determine international estimates of the economic burden of falls in older people living in the community. Our systematic review emphasized the need for a consensus on methodology for cost of falls studies to enable more accurate comparisons and subgroup-specific estimates among different countries.

INTRODUCTION

The purpose of this study was to determine international estimates of the economic burden of falls in older people living in the community.

METHODS

This is a systematic review of peer-reviewed journal articles reporting estimates for the cost of falls in people aged > or =60 years living in the community. We searched for papers published between 1945 and December 2008 in MEDLINE, PUBMED, EMBASE, CINAHL, Cochrane Collaboration, and NHS EED databases that identified cost of falls in older adults. We extracted the cost of falls in the reported currency and converted them to US dollars at 2008 prices, cost items measured, perspective, time horizon, and sensitivity analysis. We assessed the quality of the studies using a selection of questions from Drummond's checklist.

RESULTS

Seventeen studies met our inclusion criteria. Studies varied with respect to viewpoint of the analysis, definition of falls, identification of important and relevant cost items, and time horizon. Only two studies reported a sensitivity analysis and only four studies identified the viewpoint of their economic analysis. In the USA, non-fatal and fatal falls cost US $23.3 billion (2008 prices) annually and US $1.6 billion in the UK.

CONCLUSIONS

The economic cost of falls is likely greater than policy makers appreciate. The mean cost of falls was dependent on the denominator used and ranged from US $3,476 per faller to US $10,749 per injurious fall and US $26,483 per fall requiring hospitalization. A consensus on methodology for cost of falls studies would enable more accurate comparisons and subgroup-specific estimates among different countries.

Spectroscopic fingerprint of phase-incoherent superconductivity in the cuprate pseudogap state [corrected]

A possible explanation for the existence of the cuprate "pseudogap" state is that it is a d-wave superconductor without quantum phase rigidity. Transport and thermodynamic studies provide compelling evidence that supports this proposal, but few spectroscopic explorations of it have been made. One spectroscopic signature of d-wave superconductivity is the particle-hole symmetric "octet" of dispersive Bogoliubov quasiparticle interference modulations. Here we report on this octet's evolution from low temperatures to well into the underdoped pseudogap regime. No pronounced changes occur in the octet phenomenology at the superconductor's critical temperature Tc, and it survives up to at least temperature T approximately 1.5 Tc. In this pseudogap regime, we observe the detailed phenomenology that was theoretically predicted for quasiparticle interference in a phase-incoherent d-wave superconductor. Thus, our results not only provide spectroscopic evidence to confirm and extend the transport and thermodynamics studies, but they also open the way for spectroscopic explorations of phase fluctuation rates, their effects on the Fermi arc, and the fundamental source of the phase fluctuations that suppress superconductivity in underdoped cuprates.

Glycosylation of proteinase 3 (PR3) is not required for its reactivity with antineutrophil cytoplasmic antibodies (ANCA) in Wegener's granulomatosis

OBJECTIVE

The glycosylation status of autoantigens appears to be crucial for the pathogenesis of some autoimmune diseases, since carbohydrates play a crucial role in the distinction of self from non-self. Proteinase 3 (PR3), the main target antigen for anti-neutrophil cytoplasmic antibodies (ANCA) in patients with Wegener's granulomatosis (WG), contains two Asn-linked glycosylation sites. The present study explores the influence of the glycosylation status of PR3 on the PR3 recognition by ANCA in a well characterized population of patients with WG.

METHODS

Forty-four patients with WG (459 serum samples) who participated in a multicenter randomized trial, were tested by capture ELISA for ANCA against PR3 and deglycosylated recombinant variants of PR3.

RESULTS

The patients were followed for a median of 27 months, and the median number of serum samples per patient was 10. At baseline, the correlation between the levels of ANCA against PR3 and against all the deglycosylated recombinant variants of PR3 were greater than 0.94 (?<0.001 for all the comparisons). Longitudinal analyses comparing the levels of ANCA against PR3 versus all the deglycosylated recombinant variants of PR3, using linear mixed models, showed no significant statistical differences (rho >or=0.90 in all cases).

CONCLUSION

The glycosylation status of PR3 has no impact on its recognition by ANCA in WG.

How Cooper pairs vanish approaching the Mott insulator in Bi2Sr2CaCu2O8+delta

The antiferromagnetic ground state of copper oxide Mott insulators is achieved by localizing an electron at each copper atom in real space (r-space). Removing a small fraction of these electrons (hole doping) transforms this system into a superconducting fluid of delocalized Cooper pairs in momentum space (k-space). During this transformation, two distinctive classes of electronic excitations appear. At high energies, the mysterious 'pseudogap' excitations are found, whereas, at lower energies, Bogoliubov quasi-particles-the excitations resulting from the breaking of Cooper pairs-should exist. To explore this transformation, and to identify the two excitation types, we have imaged the electronic structure of Bi(2)Sr(2)CaCu(2)O(8+delta) in r-space and k-space simultaneously. We find that although the low-energy excitations are indeed Bogoliubov quasi-particles, they occupy only a restricted region of k-space that shrinks rapidly with diminishing hole density. Concomitantly, spectral weight is transferred to higher energy r-space states that lack the characteristics of excitations from delocalized Cooper pairs. Instead, these states break translational and rotational symmetries locally at the atomic scale in an energy-independent way. We demonstrate that these unusual r-space excitations are, in fact, the pseudogap states. Thus, as the Mott insulating state is approached by decreasing the hole density, the delocalized Cooper pairs vanish from k-space, to be replaced by locally translational- and rotational-symmetry-breaking pseudogap states in r-space.

Adalimumab effectiveness for the treatment of ankylosing spondylitis is maintained for up to 2 years: long-term results from the ATLAS trial

Objective:

To determine the long-term effect of adalimumab on patients with ankylosing spondylitis (AS) who participated in the Adalimumab Trial Evaluating Long-Term Efficacy and Safety in AS (ATLAS), a randomised, double-blind, placebo controlled, 24-week trial.

Methods:

Patients received adalimumab 40 mg every other week (eow) or placebo for 24 weeks in ATLAS. At week 24, patients were switched to open-label adalimumab 40 mg eow. Efficacy measures included 20% improvement in the Assessment in SpondyloArthritis International Society (ASAS) criteria (ASAS20), ASAS40 and ASAS partial remission responses and changes in individual components of the ASAS20 response evaluations, for example, Bath AS Functional Index (BASFI) and Bath AS Disease Activity Index (BASDAI). Two-year interim data were analysed based on the total duration of adalimumab exposure, irrespective of the treatment randomisation group.

Results:

At 2 years, 255 (82.0%) of the original 311 ATLAS patients continued receiving adalimumab treatment. Improvements in ASAS responses observed in ATLAS were sustained during long-term treatment; 64.5% (200/310) were ASAS20 responders, 50.6% (157/310) were ASAS40 responders and 33.5% (104/310) had maintained ASAS-defined partial remission. Changes in individual ASAS response components were sustained or improved during long-term adalimumab treatment. From ATLAS baseline to 2 years of adalimumab exposure, respectively, BASDAI improved from 6.3 (SD 1.7) to 2.4 (SD 2.3) and BASFI improved from 5.2 (SD 2.4) to 2.9 (SD 2.5). Adalimumab was well tolerated. No cases of tuberculosis, congestive heart failure, lupus-like symptoms, or demyelinating disease were reported.

Conclusions:

Adalimumab reduced the signs and symptoms of AS and induced partial remission for up to 2 years. The long-term safety profile was similar to the short-term safety profile.

Trial registration information:

NCT00085644

Radiographic progression of ankylosing spondylitis after up to two years of treatment with etanercept

OBJECTIVE

To investigate the effect of etanercept therapy on radiographic progression in patients with ankylosing spondylitis (AS).

METHODS

Patients with AS who had previously participated in a 24-week randomized, double-blind, placebo-controlled trial of etanercept therapy were enrolled in a 72-week open-label extension. Radiographs of the cervical and lumbar spine from patients who received etanercept (25 mg twice weekly) for up to 96 weeks were compared with radiographs from patients in a large prevalence cohort (Outcome Assessments in Ankylosing Spondylitis International Study [OASIS]) who had not been treated with anti-tumor necrosis factor alpha (anti-TNFalpha) agents. Radiographs obtained at 2 time points up to 96 weeks apart from patients in both study populations were digitized and read by 2 independent readers who were blinded with regard to patient group and sequence. The primary end point was the 96-week change in the modified Stoke AS Spine Score (mSASSS).

RESULTS

A total of 257 patients treated with etanercept were compared with 175 unselected patients from the OASIS study. There was no significant difference in the change in the mSASSS from baseline among patients who received etanercept (mean +/- SD 0.91 +/- 2.45) versus those from the OASIS group (0.95 +/- 3.18).

CONCLUSION

Unlike other inflammatory rheumatic diseases such as rheumatoid arthritis and psoriatic arthritis, structural progression in AS seems to be independent of TNF, despite the fact that TNF is responsible for the signs and symptoms due to inflammation in this disease.

Adalimumab effectively reduces the signs and symptoms of active ankylosing spondylitis in patients with total spinal ankylosis

Objective:

To evaluate the long-term safety and efficacy of adalimumab in patients with ankylosing spondylitis (AS) and total spinal ankylosis (TSA).

Design:

Patients (n = 315) with active AS were randomised in a 2:1 ratio to receive adalimumab 40 mg every other week or placebo for 24 weeks followed by open-label adalimumab for up to 5 years. Two-year efficacy and safety data for 11 patients with investigator-defined TSA were evaluated. The primary end point was the ASsessment in AS International Working Group criteria for 20% improvement (ASAS20) at Week 12. On or after Week 12, ASAS20 non-responders could switch to open-label adalimumab. Other efficacy measurements included ASAS40, ASAS 5/6, ASAS partial remission, and 50% improvement in the Bath AS Disease Activity Index (BASDAI 50).

Results:

6 of 11 TSA patients were randomised to adalimumab and 5 to placebo. At Week 12, 50% of the adalimumab-treated patients achieved an ASAS20 response and 33% achieved an ASAS40, ASAS 5/6 and BASDAI 50. No placebo-treated patients achieved any response criteria at Week 12. 4 placebo- and 2 adalimumab-treated patients switched to open-label adalimumab before Week 24. After 1 year of adalimumab treatment, 8 of 11 patients achieved an ASAS20 response. After 2 years, 6 of the remaining 8 patients with TSA reported an ASAS20 response. There were no serious adverse events or adverse event-related study discontinuations.

Conclusion:

In patients with TSA, adalimumab treatment resulted in rapid and clinically significant improvement in the signs and symptoms of active disease. Adalimumab effectiveness and safety were sustained for at least 2 years.

Trial registration number:

NCT00085644.

Clinical, radiographic and functional differences between juvenile-onset and adult-onset ankylosing spondylitis: results from the PSOAS cohort

AIMS

Previous data suggests that patients with juvenile-onset ankylosing spondylitis (JoAS) have more severe disease and worse functional outcomes than adult-onset AS (AoAS). The purpose of this study was to evaluate clinical, functional and radiographic differences between patients with JoAS and AoAS in a large cohort of patients with long-standing disease.

METHODS

A total of 402 subjects who met the Modified New York Criteria for definitive AS and had had disease >or=20 years were enrolled in a multi-centre cross-sectional study (Prospective Study of Outcomes in Ankylosing Spondylitis; PSOAS). JoAS was defined as initial symptoms <or=16 years of age. A total of 79 subjects with JoAS and 323 subjects with AoAS were identified. An analysis of clinical and demographic comparisons between the two groups was performed including HLA B27 status. Functional outcomes were assessed by Bath AS Functional Index (BASFI) and the Health Assessment Questionnaire modified for the Spondyloarthropathies (HAQS). Radiographic disease severity was assessed by the Bath AS Radiology Index (BASRI).

RESULTS

With the exception of obvious differences in age at onset and disease duration, demographic and clinical characteristics were similar between the two groups. However, the JoAS group trended towards more women (32.9 vs 22.9%, p = 0.07). Controlling for multiple covariates including disease duration, both the BASRI hip score and the need for total hip arthroplasty (THA) was higher in the JoAS group. The BASRI spine score (including total, lumbar and cervical spine) was significantly lower in the patients with JoAS even after controlling for multiple covariates including disease duration and gender. No difference in function (BASFI or HAQS scores) between groups was identified.

CONCLUSIONS

Compared to AoAS, subjects with JoAS have (1) less severe axial involvement radiographically, (2) similar functional outcomes, (3) more hip involvement with a greater need for THA, and (4) a slightly higher proportion of women.

An Intrinsic Bond-Centered Electronic Glass with Unidirectional Domains in Underdoped Cuprates

Removing electrons from the CuO2 plane of cuprates alters the electronic correlations sufficiently to produce high-temperature superconductivity. Associated with these changes are spectral-weight transfers from the high-energy states of the insulator to low energies. In theory, these should be detectable as an imbalance between the tunneling rate for electron injection and extraction-a tunneling asymmetry. We introduce atomic-resolution tunneling-asymmetry imaging, finding virtually identical phenomena in two lightly hole-doped cuprates: Ca(1.88)Na(0.12)CuO(2)Cl2 and Bi2Sr2Dy(0.2)Ca(0.8)Cu2O(8+delta). Intense spatial variations in tunneling asymmetry occur primarily at the planar oxygen sites; their spatial arrangement forms a Cu-O-Cu bond-centered electronic pattern without long-range order but with 4a(0)-wide unidirectional electronic domains dispersed throughout (a(0): the Cu-O-Cu distance). The emerging picture is then of a partial hole localization within an intrinsic electronic glass evolving, at higher hole densities, into complete delocalization and highest-temperature superconductivity.

Hand dominance and bone response after a distal radial fracture: a peripheral QCT study

There are no reports on bone geometry or volumetric bone density adaptations in those who have sustained a distal radial fracture. We used peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) to quantify bone and muscle response to immobilization. We measured side-side differences in women aged > or =50 yr who had previously sustained a wrist fracture (4.0+/-3.5 mean yr since fracture). We used pQCT and DXA to measure bone in 31 women (mean age 72.4+/-9.7 yr) at the 4% and 30% sites of bilateral radii; measured grip strength and functional outcome. Initially, we compared the fractured side to intact side and did not control for hand dominance. We observed greater total area (ToA) at the distal (4%) radius on the fractured side without a significant increase in density. At the midshaft (30% site), we observed significantly less ToA and cortical bone on the fracture side. Grip strength was also significantly less on the fractured side (p<0.01). We assessed dominant side fractures and nondominant fractures separately. We observed a greater discrepancy between limbs with a nondominant side fracture, even after accounting for dominance. This cross-sectional study suggests that the bone response to a nondominant fracture may differ from a dominant fracture.

The Ground State of the Pseudogap in Cuprate Superconductors

We present studies of the electronic structure of La(2-x)BaxCuO4, a system where the superconductivity is strongly suppressed as static spin and charge orders or "stripes" develop near the doping level of x = (1/8). Using angle-resolved photoemission and scanning tunneling microscopy, we detect an energy gap at the Fermi surface with magnitude consistent with d-wave symmetry and with linear density of states, vanishing only at four nodal points, even when superconductivity disappears at x = (1/8). Thus, the nonsuperconducting, striped state at x = (1/8) is consistent with a phase-incoherent d-wave superconductor whose Cooper pairs form spin-charge-ordered structures instead of becoming superconducting.

Effects of pairing potential scattering on Fourier-transformed inelastic tunneling spectra of high-Tc cuprate superconductors with bosonic modes

Recent scanning tunneling microscopy (STM) experimentally observed strong gap inhomogeneity in Bi2Sr2CaCu2O(8+delta) (BSCCO). We argue that disorder in the pair potential underlies the gap inhomogeneity, and investigate its role in the Fourier-transformed inelastic tunneling spectra as revealed in the STM. We find that the random pair potential induces unique q-space patterns in the local density of states (LDOS) of a d-wave superconductor. We consider the effects of electron coupling to various bosonic modes and find the pattern of LDOS modulation due to coupling to the B(1g) phonon mode to be consistent with the one observed in the inelastic electron tunnneling STM experiment in BSCCO. These results suggest strong electron-lattice coupling as an essential part of the superconducting state in high-Tc materials.

Interplay of electron–lattice interactions and superconductivity in Bi2Sr2CaCu2O8+δ

Formation of electron pairs is essential to superconductivity. For conventional superconductors, tunnelling spectroscopy has established that pairing is mediated by bosonic modes (phonons); a peak in the second derivative of tunnel current d2I/dV2 corresponds to each phonon mode. For high-transition-temperature (high-T(c)) superconductivity, however, no boson mediating electron pairing has been identified. One explanation could be that electron pair formation and related electron-boson interactions are heterogeneous at the atomic scale and therefore challenging to characterize. However, with the latest advances in d2I/dV2 spectroscopy using scanning tunnelling microscopy, it has become possible to study bosonic modes directly at the atomic scale. Here we report d2I/dV2 imaging studies of the high-T(c) superconductor Bi2Sr2CaCu2O8+delta. We find intense disorder of electron-boson interaction energies at the nanometre scale, along with the expected modulations in d2I/dV2 (refs 9, 10). Changing the density of holes has minimal effects on both the average mode energies and the modulations, indicating that the bosonic modes are unrelated to electronic or magnetic structure. Instead, the modes appear to be local lattice vibrations, as substitution of 18O for 16O throughout the material reduces the average mode energy by approximately 6 per cent--the expected effect of this isotope substitution on lattice vibration frequencies. Significantly, the mode energies are always spatially anticorrelated with the superconducting pairing-gap energies, suggesting an interplay between these lattice vibration modes and the superconductivity.

Definition of disease duration in ankylosing spondylitis: reassessing the concept

The concept and definition of disease duration in patients with ankylosing spondylitis is ambiguous, and often many years pass between the onset of symptoms and diagnosis. Members of the Assessment in Ankylosing Spondylitis (ASAS) International Working Group by consensus recently recommended identifying specific components of the medical history to better define and document the concept of disease duration. These include (1) the time of onset of the first symptoms of axial manifestations (including inflammatory back pain); (2) the time of onset of the first symptoms of each individual manifestation, which may be an extra-axial sign or symptom of ankylosing spondylitis, such as peripheral arthritis and enthesitis; (3) the time of onset of associated diseases belonging to the spondyloarthritides, in particular acute anterior uveitis, inflammatory bowel disease and psoriasis; and (4) the time since actual diagnosis by a healthcare provider. Such uniformity in data collection will ensure comparability across studies and facilitate future research.

Community-dwelling seniors who present to the emergency department with a fall do not receive Guideline care and their fall risk profile worsens significantly: a 6-month prospective study

INTRODUCTION

Fall risk is a major contributor to fracture risk; implementing fall reduction programmes remains a challenge for health professionals and policy-makers.

MATERIALS AND METHODS

We aimed to (1) ascertain whether the care received by 54 older adults after an emergency department (ED) fall presentation met internationally recommended 'Guideline Care', and (2) prospectively evaluate this cohort's 6-month change in fall risk profile. Participants were men and women aged 70 years or older who were discharged back into the community after presenting to an urban university tertiary-care hospital emergency department with a fall-related complaint. American Geriatric Society (AGS) guideline care was documented by post-presentation emergency department chart examination, daily patient diary of falls submitted monthly, patient interview and physician reconciliation where needed. Both at study entry and at a 6-month followup, we measured participants physiological characteristics by Lord's Physiological Profile Assessment (PPA), functional status, balance confidence, depression, physical activity and other factors.

RESULTS

We found that only 2 of 54 (3.7%) of the fallers who presented to the ED received care consistent with AGS Guidelines. Baseline physiological fall risk scores classified the study population at a 1.7 SD higher risk than a 65-year-old comparison group, and during the 6-month followup period the mean fall-risk score increased significantly (i.e. greater risk of falls) (1.7+/-1.6 versus 2.2+/-1.6, p=0.000; 29.5% greater risk of falls). Also, functional ability [100 (15) versus 95 (25), p=0.002], balance confidence [82.5 (44.4) versus 71.3 (58.7), p=0.000] and depression [0 (2) versus 0 (3), p=0.000] all worsened over 6 months. Within 6 months of the index ED visit, five participants had suffered six fall-related fractures.

DISCUSSION

We conclude that this group of community-dwelling fallers, who presented for ED care with a clinical profile suggesting a high risk of further falls and fracture, did not receive Guideline care and worsened in their fall risk profile by 29.5%. This gap in care, at least in one centre, suggests further investigation into alternative approaches to delivering Guideline standard health service.

The post-operative analgesic efficacy and tolerability of lumiracoxib compared with placebo and naproxen after total knee or hip arthroplasty

BACKGROUND

Lumiracoxib is a novel selective cyclooxygenase-2 (COX-2) inhibitor in development for the treatment of chronic and acute pain.

METHODS

This randomized, double-blind multicentre study enrolled 180 patients (aged 18-80 years) with moderate-to-severe pain (>or=2 on a 4-point categorical scale) within 48 h of unilateral total knee or total hip arthroplasty. Patients were randomized to receive lumiracoxib 400 mg once daily (n = 60), placebo (n = 60) or naproxen 500 mg twice daily (n = 60). The study consisted of a 12-h single-dose phase followed by a multiple-dose phase (up to 96 h or until discontinuation). The primary efficacy measure was the summed (time-weighted) pain intensity difference over 0-8 h after the first dose (SPID-8).

RESULTS

Lumiracoxib and naproxen were comparable and both treatments were superior to placebo for the primary efficacy measure, SPID-8. Both treatments were generally similar and also superior to placebo for the secondary efficacy measures during both the single- and multiple-dose phases for up to 96 h. Both active treatments were well tolerated.

CONCLUSION

Lumiracoxib is an effective alternative to traditional non-selective non-steroidal anti-inflammatory drugs (NSAIDs) for the treatment of post-operative pain.

ASAS/EULAR recommendations for the management of ankylosing spondylitis

OBJECTIVE

To develop evidence based recommendations for the management of ankylosing spondylitis (AS) as a combined effort of the 'ASsessment in AS' international working group and the European League Against Rheumatism.

METHODS

Each of the 22 participants was asked to contribute up to 15 propositions describing key clinical aspects of AS management. A Delphi process was used to select 10 final propositions. A systematic literature search was then performed to obtain scientific evidence for each proposition. Outcome data for efficacy, adverse effects, and cost effectiveness were abstracted. The effect size, relative risk, number needed to treat, and incremental cost effectiveness ratio were calculated. On the basis of the search results, 10 major recommendations for the management of AS were constructed. The strength of recommendation was assessed based on the strength of the literature evidence, risk-benefit trade-off, and clinical expertise.

RESULTS

The final recommendations considered the use of non-steroidal anti-inflammatory drugs (NSAIDs) (conventional NSAIDs, coxibs, and co-prescription of gastroprotective agents), disease modifying antirheumatic drugs, treatments with biological agents, simple analgesics, local and systemic steroids, non-pharmacological treatment (including education, exercise, and physiotherapy), and surgical interventions. Three general recommendations were also included. Research evidence (categories I-IV) supported 11 interventions in the treatment of AS. Strength of recommendation varied, depending on the category of evidence and expert opinion.

CONCLUSION

Ten key recommendations for the treatment of AS were developed and assessed using a combination of research based evidence and expert consensus. Regular updating will be carried out to keep abreast of new developments in the management of AS.

Atomic-Scale Sources and Mechanism of Nanoscale Electronic Disorder in Bi2Sr2CaCu2O8+

The randomness of dopant atom distributions in cuprate high-critical temperature superconductors has long been suspected to cause nanoscale electronic disorder. In the superconductor Bi2Sr2CaCu2O8+delta, we identified populations of atomic-scale impurity states whose spatial densities follow closely those of the oxygen dopant atoms. We found that the impurity-state locations are strongly correlated with all manifestations of the nanoscale electronic disorder. This disorder occurs via an unanticipated mechanism exhibiting high-energy spectral weight shifts, with associated strong superconducting coherence peak suppression but very weak scattering of low-energy quasi-particles.

Coincidence of checkerboard charge order and antinodal state decoherence in strongly underdoped superconducting Bi2Sr2CaCu2O8 + delta)

The doping dependence of nanoscale electronic structure in superconducting Bi(2)Sr(2)CaCu(2)O(8 + delta) is studied by scanning tunneling microscopy. At all dopings, the low energy density-of-states modulations are analyzed according to a simple model of quasiparticle interference and found to be consistent with Fermi-arc superconductivity. The superconducting coherence peaks, ubiquitous in near-optimal tunneling spectra, are destroyed with strong underdoping and a new spectral type appears. Exclusively in regions exhibiting this new spectrum, we find local "checkerboard" charge ordering of high energy states, with a wave vector of Q = (+/- 2pi/4.5a(0),0); (0, +/- 2pi/4.5a(0)) +/- 15%. Surprisingly, this spatial ordering of high energy states coexists harmoniously with the low energy Bogoliubov quasiparticle states.

Type I interferon correlates with serological and clinical manifestations of SLE

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting multiple organ systems triggered by the production of autoantibodies. Previous clinical studies in humans and murine models suggest that type I interferons (IFNs) are important for the initiation and potentiation of SLE activity.

METHODS

65 consecutive patients with SLE were identified from the University of California, San Francisco Lupus Clinic with moderate-severe disease activity. 94 serological samples were collected. Type I IFN levels and the ability of plasma to induce expression of several surface markers of dendritic cell maturation were measured.

RESULTS

Type I IFN levels correlated with the presence of cutaneous manifestations, and there was a trend towards correlation with renal disease. No correlation was found between type I IFN levels and neurological disease. Type I IFN levels correlated positively with the SLEDAI score and anti-dsDNA levels and inversely with C3 levels. Interestingly, type I IFN levels were highest in African American patients. SLE plasma also induced the expression of MHC class I, CD38, and CD123 on monocytes, and was blocked by the addition of a monoclonal antibody to IFNAR1.

CONCLUSIONS

The pathogenic role of type I IFN is suggested by the induction of cell surface markers for dendritic cell maturation. The potential therapeutic utility of antibodies directed to either type I IFN or IFNAR1/IFNAR2 may be of interest in further studies.

Sustained durability and tolerability of etanercept in ankylosing spondylitis for 96 weeks

OBJECTIVE

To evaluate the continued safety and durability of clinical response in patients with ankylosing spondylitis receiving etanercept.

METHODS

277 patients who had participated in a previous randomised, double blind, placebo controlled 24 week trial were eligible to continue in this open label extension study. All patients who enrolled in the open label extension (n = 257) received subcutaneous etanercept 25 mg twice weekly for up to 72 weeks, for a combined 96 weeks of cumulative trial and open label experience. For the patients who had received etanercept for 24 weeks in the double blind trial, this represented almost 2 years of continuous etanercept treatment.

RESULTS

Patients continuing etanercept treatment had a sustained response for almost 2 years, with 74% achieving an ASsessments in Ankylosing Spondylitis 20% (ASAS 20) response after 96 weeks of etanercept treatment. Patients who had received placebo in the preceding double blind trial had similar responses, with 70% of patients attaining an ASAS 20 response after 24 weeks of etanercept treatment and 78% achieving an ASAS 20 response after 72 weeks. Improved spinal mobility was seen in both groups. Etanercept was well tolerated in patients treated for up to 96 weeks.

CONCLUSION

The subcutaneous administration of twice weekly doses of etanercept provided sustained durability of response in the improvement of signs and symptoms of ankylosing spondylitis for nearly 2 years.

Lamivudine is not effective in primary Sjögren's syndrome

BACKGROUND

Retroviral infection has been implicated in the pathogenesis of primary Sjögren's syndrome.

OBJECTIVE

To examine the efficacy of the reverse transcriptase inhibitor lamivudine in patients with this syndrome.

METHODS

16 patients with primary Sjögren's syndrome were randomised to receive either lamivudine 150 mg twice daily or placebo for three months. Measures of lacrimal and salivary function, including minor salivary gland biopsies, were obtained before and after treatment.

RESULTS

Treatment with lamivudine did not result in significant improvement in the primary outcome measure of unstimulated whole salivary flow or other secondary measures, including minor salivary gland biopsy focus scores.

CONCLUSION

Lamivudine is not effective in patients with primary Sjögren's syndrome, suggesting either that a retroviral aetiology is not present or that it may be important only in early disease.

The role of balance and agility training in fall reduction. A comprehensive review

AIM

In the elderly, falls and fall-related injuries are a major problem worldwide and the number of injuries are continuing to increase. It is well established that stability requires a well-functioning muscular-skeletal system as well as an intact balance system. The purpose of this comprehensive review of controlled trials is to examine the evidence for the value of balance and agility training in preventing falls and injuries resulting from falls in older people.

METHODS

Thirteen studies meeting our inclusion criteria have been reviewed.

RESULTS

Of these 13 studies, 6 demonstrated a significant reduction in the rate of falls.

CONCLUSIONS

The conclusion is drawn that an exercise program with a balance component in healthy community dwelling older people is likely to prevent future falls.

A ‘checkerboard’ electronic crystal state in lightly hole-doped Ca2-xNaxCuO2Cl2

The phase diagram of hole-doped copper oxides shows four different electronic phases existing at zero temperature. Familiar among these are the Mott insulator, high-transition-temperature superconductor and metallic phases. A fourth phase, of unknown identity, occurs at light doping along the zero-temperature bound of the 'pseudogap' regime. This regime is rich in peculiar electronic phenomena, prompting numerous proposals that it contains some form of hidden electronic order. Here we present low-temperature electronic structure imaging studies of a lightly hole-doped copper oxide: Ca2-xNaxCuO2Cl2. Tunnelling spectroscopy (at energies |E| > 100 meV) reveals electron extraction probabilities greatly exceeding those for injection, as anticipated for a doped Mott insulator. However, for |E| < 100 meV, the spectrum exhibits a V-shaped energy gap centred on E = 0. States within this gap undergo intense spatial modulations, with the spatial correlations of a four CuO2-unit-cell square 'checkerboard', independent of energy. Intricate atomic-scale electronic structure variations also exist within the checkerboard. These data are consistent with an unanticipated crystalline electronic state, possibly the hidden electronic order, existing in the zero-temperature pseudogap regime of Ca2-xNaxCuO2Cl2.

Lymphocyte depletion with fludarabine in patients with psoriatic arthritis: clinical and immunological effects

OBJECTIVE

To obtain preliminary information on the safety and efficacy of fludarabine in PsA and analyse its immunomodulatory effects in peripheral blood and synovial tissue.

METHODS

15 patients with active PsA who did not respond to DMARDs were randomly allocated to receive fludarabine every four weeks or placebo. Primary outcomes were the proportion of patients who met the ACR20 and the psoriatic arthritis response criteria (PsARC) at 16 weeks. Secondary outcomes were changes in tender or swollen joint counts and scores of the psoriasis area and severity index (PASI). Phenotypic analysis of peripheral blood mononuclear cells (PBMC), synovial immunohistochemistry, and functional analysis of PBMC were used to determine the immunomodulatory effects of fludarabine.

RESULTS

At 16 weeks the ACR20 criteria were met by 3/7 (43%) fludarabine treated v 0/8 placebo treated patients (p=0.08); the PsARC was achieved by 4/7 (57%) fludarabine treated v 2/8 (25%) placebo treated patients; and 3/7 (43%) fludarabine treated v 0/7 placebo treated patients had > or =20% improvement in the PASI. Marked peripheral lymphopenia involving naive (CD4(+) CD45RA(+)) and memory (CD4(+) CD45RO(+)) T cells, CD8(+) T cells, and B cells was seen in fludarabine treated patients.

CONCLUSIONS

In PsA fludarabine induces significant peripheral, but modest, synovial lymphopenia, and a trend towards improved clinical response.

Relating atomic-scale electronic phenomena to wave-like quasiparticle states in superconducting Bi2Sr2CaCu2O8+delta

The electronic structure of simple crystalline solids can be completely described in terms either of local quantum states in real space (r-space), or of wave-like states defined in momentum-space (k-space). However, in the copper oxide superconductors, neither of these descriptions alone may be sufficient. Indeed, comparisons between r-space and k-space studies of Bi2Sr2CaCu2O8+delta (Bi-2212) reveal numerous unexplained phenomena and apparent contradictions. Here, to explore these issues, we report Fourier transform studies of atomic-scale spatial modulations in the Bi-2212 density of states. When analysed as arising from quasiparticle interference, the modulations yield elements of the Fermi-surface and energy gap in agreement with photoemission experiments. The consistency of numerous sets of dispersing modulations with the quasiparticle interference model shows that no additional order parameter is required. We also explore the momentum-space structure of the unoccupied states that are inaccessible to photoemission, and find strong similarities to the structure of the occupied states. The copper oxide quasiparticles therefore apparently exhibit particle-hole mixing similar to that of conventional superconductors. Near the energy gap maximum, the modulations become intense, commensurate with the crystal, and bounded by nanometre-scale domains. Scattering of the antinodal quasiparticles is therefore strongly influenced by nanometre-scale disorder.

The treatment of ankylosing spondylitis

Ankylosing spondylitis is an inflammatory disorder affecting the axial skeleton and periphery. Symptoms can often be debilitating. Current therapy for the disease include physical therapy, non-steroidal anti-inflammatory drugs (NSAIDS, anti-rheumatic disease modifying drugs (DMARDS), and the newly developed biologic agents targeting tumor necrosis factor alpha (TNF-alpha). This paper will provide a comprehensive review of these treatments which focusing on evidence based medicine for the daily clinical practice of rheumatology.