Multiple-camera defocus imaging of ultracold atomic gases.

In cold atom experiments, each image of light refracted and absorbed by an atomic ensemble carries a remarkable amount of information. Numerous imaging techniques including absorption, fluorescence, and phase-contrast are commonly used. Other techniques such as off-resonance defocused imaging (ORDI, [1-4]), where an in-focus image is deconvolved from a defocused image, have been demonstrated but find only niche applications. The ORDI inversion process introduces systematic artifacts because it relies on regularization to account for missing information at some spatial frequencies. In the present work, we extend ORDI to use multiple cameras simultaneously at degrees of defocus, eliminating the need for regularization and its attendant artifacts. We demonstrate this technique by imaging Bose-Einstein condensates, and show that the statistical uncertainties in the measured column density using the multiple-camera off-resonance defocused (McORD) imaging method are competitive with absorption imaging near resonance and phase contrast imaging far from resonance. Experimentally, the McORD method may be incorporated into existing set-ups with minimal additional equipment.

All-optical intrinsic atomic gradiometer with sub-20 fT/cm/√Hz sensitivity in a 22 µT earth-scale magnetic field.

In this work we demonstrate a high sensitivity atomic gradiometer capable of operation in earth-field level environments. We apply a light-pulse sequence at four times the Larmor frequency to achieve gradiometer sensitivity <20 fT/cm/Hz at the finite field strength of 22 µT. The experimental timing sequence can be tuned to the field magnitude of interest. Our all-optical scalar gradiometer performs a differential measurement between two regions of a single vapor cell on a 4 cm baseline. Our results pave the way for extensions to operation in higher dimensions, vector sensitivity, and more advanced gradiometers.

Characterization of noise sources in a microfabricated single-beam zero-field optically-pumped magnetometer.

We present an experimental noise characterization of a miniature single-beam absorption-based optically-pumped magnetometer with a noise floor of 7 fT/Hz1/2 operating in the spin-exchange relaxation-free regime. We experimentally evaluate noise arising from the laser intensity, laser frequency, laser polarization, cell temperature, and magnetic field coils used for the phase-sensitive detection of the magnetometer signal. We find that noise in the range between DC and 30 Hz is a result of noise sources coupling to the atoms in a manner similar to a magnetic field, while the noise at frequencies above 30 Hz is mainly due to laser intensity noise. Our results place an upper limit on the noise sources for our system that matches well with the noise spectrum of the magnetometer at frequencies above 5 Hz.

A microfabricated optically-pumped magnetic gradiometer.

We report on the development of a microfabricated atomic magnetic gradiometer based on optical spectroscopy of alkali atoms in the vapor phase. The gradiometer, which operates in the spin-exchange relaxation free regime, has a length of 60 mm and cross sectional diameter of 12 mm, and consists of two chip-scale atomic magnetometers which are interrogated by a common laser light. The sensor can measure differences in magnetic fields, over a 20 mm baseline, of 10 fT/[Formula: see text] at frequencies above 20 Hz. The maximum rejection of magnetic field noise is 1000 at 10 Hz. By use of a set of compensation coils wrapped around the sensor, we also measure the sensor sensitivity at several external bias field strengths up to 150 mG. This device is useful for applications that require both sensitive gradient field information and high common-mode noise cancellation.

The spin Hall effect in a quantum gas.

Electronic properties such as current flow are generally independent of the electron's spin angular momentum, an internal degree of freedom possessed by quantum particles. The spin Hall effect, first proposed 40 years ago, is an unusual class of phenomena in which flowing particles experience orthogonally directed, spin-dependent forces--analogous to the conventional Lorentz force that gives the Hall effect, but opposite in sign for two spin states. Spin Hall effects have been observed for electrons flowing in spin-orbit-coupled materials such as GaAs and InGaAs (refs 2, 3) and for laser light traversing dielectric junctions. Here we observe the spin Hall effect in a quantum-degenerate Bose gas, and use the resulting spin-dependent Lorentz forces to realize a cold-atom spin transistor. By engineering a spatially inhomogeneous spin-orbit coupling field for our quantum gas, we explicitly introduce and measure the requisite spin-dependent Lorentz forces, finding them to be in excellent agreement with our calculations. This 'atomtronic' transistor behaves as a type of velocity-insensitive adiabatic spin selector, with potential application in devices such as magnetic or inertial sensors. In addition, such techniques for creating and measuring the spin Hall effect are clear prerequisites for engineering topological insulators and detecting their associated quantized spin Hall effects in quantum gases. As implemented, our system realizes a laser-actuated analogue to the archetypal semiconductor spintronic device, the Datta-Das spin transistor.

Peierls substitution in an engineered lattice potential.

Artificial gauge fields open the possibility to realize quantum many-body systems with ultracold atoms, by engineering Hamiltonians usually associated with electronic systems. In the presence of a periodic potential, artificial gauge fields may bring ultracold atoms closer to the quantum Hall regime. Here, we describe a one-dimensional lattice derived purely from effective Zeeman shifts resulting from a combination of Raman coupling and radio-frequency magnetic fields. In this lattice, the tunneling matrix element is generally complex. We control both the amplitude and the phase of this tunneling parameter, experimentally realizing the Peierls substitution for ultracold neutral atoms.

Synthetic partial waves in ultracold atomic collisions.

Interactions between particles can be strongly altered by their environment. We demonstrate a technique for modifying interactions between ultracold atoms by dressing the bare atomic states with light, creating an effective interaction of vastly increased range that scatters states of finite relative angular momentum at collision energies where only s-wave scattering would normally be expected. We collided two optically dressed neutral atomic Bose-Einstein condensates with equal, and opposite, momenta and observed that the usual s-wave distribution of scattered atoms was altered by the appearance of d- and g-wave contributions. This technique is expected to enable quantum simulation of exotic systems, including those predicted to support Majorana fermions.

Bose-Einstein condensate in a uniform light-induced vector potential.

We use a two-photon dressing field to create an effective vector gauge potential for Bose-Einstein-condensed 87Rb atoms in the F=1 hyperfine ground state. These Raman-dressed states are spin and momentum superpositions, and we adiabatically load the atoms into the lowest energy dressed state. The effective Hamiltonian of these neutral atoms is like that of charged particles in a uniform magnetic vector potential whose magnitude is set by the strength and detuning of the Raman coupling. The spin and momentum decomposition of the dressed states reveals the strength of the effective vector potential, and our measurements agree quantitatively with a simple single-particle model. While the uniform effective vector potential described here corresponds to zero magnetic field, our technique can be extended to nonuniform vector potentials, giving nonzero effective magnetic fields.

Evaluation of functional outcomes (speech, swallowing and voice) in patients attending speech pathology after head and neck cancer treatment(s): development of a multi-centre database.

Since April 1997, in Melbourne, Australia, speech pathologists have collaborated to establish a prospective database of functional outcomes of speech, swallowing and voice for patients undergoing head and neck cancer treatments. Staff at eight acute care hospitals, all of which offer speech pathology for head and neck cancer services in Victoria, are contributing data, collated centrally, in an agreed pro forma. Early results are given (after 12 months' data collection). The implications for clinically-based research, and the future potential for benchmarking outcomes--by expansion of the rehabilitation database beyond the current participating sites--is discussed. This paper outlines the rationale of establishing the database is multicentered, and explores some of the complexities involved, including the challenges inherent in long-term accurate data collection in the head and neck cancer patient population. This work represents the development of an appropriate, usable tool for data collection on functional outcomes.

Further evidence of associations of type a personality scores and driving-related attitudes and behaviors.

The present study examined the effects of Type A personality on specific self-reported driving attitudes and behaviors when operating a motor vehicle. 102 undergraduate students completed the student version of the Jenkins Activity Survey (Form T) and several questionnaires asking participants about their driving history, driving attitudes, and driving behaviors. When the full range of Type A scores were examined, Type A personality was significantly related to more traffic accidents, greater frequency of breaking traffic laws, higher impatience when driving, more displays of aggression on the road, and engaging in more risky driving behaviors (rs<.17). When extreme Type A and Type B scores were compared, Type A drivers reported being involved in significantly more motor vehicle accidents and reported displaying more aggression on the road. Further research should examine actual behavioral data using more diverse samples to validate the results.

Bone marrow transplant patients with life-threatening organ failure: when should treatment stop?

PURPOSE: To discuss issues surrounding life support in bone marrow transplant (BMT) patients, issues that may determine how far we go to keep a deteriorating BMT patient alive--and when we stop trying. How can we define survival chance in BMT patients, and when should prolongation of life be deemed inappropriate? Who should make the decision to terminate support? And how should life support be terminated? DESIGN: Prognostic factors that predict for almost certain nonsurvival have been identified in BMT patients with life-threatening organ failure. The concept of futility raises the question of how low the chance of survival must be before termination of life support is justified--but the concept is flawed, and the value judgments involved in decision making must also be considered. Then, once a decision is made, the manner of withholding or withdrawing life support is also open to discussion. CONCLUSION: Despite controversies, there are areas in which improvements to current practice might be considered. More data are required to determine survival chances of BMT patients with life-threatening organ failure. Greater attention might be devoted, in pretransplant counseling, to issues of intensive life support, with the patient's own views being ascertained before transplantation. And, because technologic possibilities are now imposing fewer boundaries, the problem of finite resources may need to be readdressed, with treatment limits being set down before transplantation.

Peripheral blood stem cell versus autologous bone marrow transplantation for Hodgkin's disease: equivalent survival outcome in a single-centre matched-pair analysis.

A matched-pair retrospective analysis was used to compare 70 patients who had undergone peripheral blood stem cell transplantation (PBSCT) with 70 who had undergone autologous bone marrow transplantation (ABMT) for Hodgkin's disease. All transplants took place at a single centre using the same conditioning regimen (BEAM). Patients were matched for sex, previous chemotherapy and relapse status: factors which have previously been shown to have prognostic significance for transplant outcome in Hodgkin's disease at this centre. The two groups were also generally comparable for unmatched patient and disease characteristics. Toxic deaths and 90 d outcome were not different between the two groups. Three-year overall survival was 68.6% for the ABMT group and 78.2% for the PBSCT group (P = 0.078); progression-free survival was 59.4% for the ABMT group and 58.1% for the PBSCT group (P = 0.255), and relapse rates were 36.9% and 42.6% respectively (P = 0.30). Within the limitations of retrospective analysis, we conclude that there is no major overall or progression-free survival advantage for PBSCT compared to ABMT in Hodgkin's disease.

A fatal case of autoimmune thrombocytopenia with an IgM anti-GPIb/IX following one antigen mismatched unrelated donor bone marrow transplantation.

We report the case of a 32-year-old patient with ALL who developed autoimmune thrombocytopenia 2 months following allogeneic bone marrow transplantation. An IgM autoantibody against the platelet glycoprotein Ib/IX complex was observed. Treatment with high-dose steroids and intravenous immunoglobulin G failed to produce any benefit and the thrombocytopenia led to fatal gastrointestinal haemorrhage. The possible factors contributing to post-allograft thrombocytopenia and potential management strategies are discussed.

Bcl10 is involved in t(1;14)(p22;q32) of MALT B cell lymphoma and mutated in multiple tumor types.

MALT B cell lymphomas with t(1;14)(p22;q32) showed a recurrent breakpoint upstream of the promoter of a novel gene, Bcl10. Bcl10 is a cellular homolog of the equine herpesvirus-2 E10 gene: both contain an amino-terminal caspase recruitment domain (CARD) homologous to that found in several apoptotic molecules. Bcl10 and E10 activated NF-kappaB but caused apoptosis of 293 cells. Bcl10 expressed in a MALT lymphoma exhibited a frameshift mutation resulting in truncation distal to the CARD. Truncated Bcl10 activated NF-kappaB but did not induce apoptosis. Wild-type Bcl10 suppressed transformation, whereas mutant forms had lost this activity and displayed gain-of-function transforming activity. Similar mutations were detected in other tumor types, indicating that Bcl10 may be commonly involved in the pathogenesis of human malignancy.

A case of EBV-associated lymphoproliferative disease following high-dose therapy and CD34-purified autologous peripheral blood progenitor cell transplantation.

A fatal case of EBV-associated lymphoproliferative disorder arising after a CD34-selected autologous peripheral blood stem cell transplant is reported in a patient with multiple myeloma in first plateau phase. It is suggested that this is likely to be a consequence of the accessory cell depletion associated with the CD34+ cell purification and it is recommended that a source of autologous T cells is stored before transplantation to be used if a severe opportunistic infection or EBV lymphoma arises post-transplantation.

Progenitor cell yields are frequently poor in patients with histologically indolent lymphomas especially when mobilized within 6 months of previous chemotherapy.

High-dose therapy with peripheral blood stem cell (PBSC) support is a frequently used treatment option in younger patients with poor prognosis histologically indolent (low-grade) non-Hodgkin's lymphoma (NHL), usually at the time of second or subsequent response to conventional-dose therapy. We have undertaken PBSC collection in 57 patients with histologically indolent NHL mobilized with either cyclophosphamide 1.5 g/m2 or the ESHAP regimen, followed by daily G-CSF. Progenitor cell yields were determined by quantification of CD34+ cells and GM-CFC. Twelve patients (21%) failed to achieve the minimum progenitor cell requirements of 1 x 10(6)/kg CD34+ cells or 1 x 10(5)/kg GM-CFC in their pooled harvests and 40 patients (70%) failed to achieve the optimal harvest thresholds of 3.5 x 10(6)/kg CD34+ cells or 3.5 x 10(5)/kg GM-CFC. This high failure rate is significantly higher than that in patients with histologically aggressive NHL or Hodgkin's disease. A multivariate analysis was performed to identify factors contributing to the low stem cell yields in this group. This identified the time interval from the last chemotherapy to the priming chemotherapy as the most important predictive factor. With respect to CD34 and GM-CFC numbers, on the single harvest on the day the white cell count first exceeded 5 x 10(9)/l the P values were 0.0078 and 0.0065, respectively, and for the progenitor cell values on the pooled harvests the P values were 0.004 for CD34+ cells and 0.015 for GM-CFC. Progenitor cell yields may therefore be improved in patients with low grade lymphoma by harvesting at diagnosis if no marrow disease is present, or by delaying mobilization for 6 months post-chemotherapy in patients in first or subsequent remission.

High-dose therapy for diffuse large-cell lymphoma in first remission.

Diffuse large-cell lymphoma (DLCL) is curable by first-line conventional chemotherapy in 50%-60% of patients. High-dose therapy makes no contribution to this group of patients and, if applied indiscriminately as first-line consolidation therapy, is likely to unnecessarily increase overall morbidity and mortality. Instead, recent interest has been directed towards (a) the identification of a group of patients with a poor prognosis, and (b) the intensification of first-line treatment for such patients with high-dose therapy and allied regimens. Many prognostic factors have now been standardised, while studies are progressing in the identification of newer prognostic factors, such as the molecular markers. Multi-centre randomised trials are currently in progress to determine the appropriate level of treatment for prognostic subsets, with the value of high-dose therapy being assessed for those in the worst prognostic groups.

Back-up bone marrow is frequently ineffective in patients with poor peripheral-blood stem-cell mobilization.

PURPOSE: To assess hematologic recovery and procedure-related mortality in patients who received high-dose therapy with stem-cell support, in whom the peripheral-blood stem-cell (PBSC) collection fails (CD34+ cells < 1 x 10(6)/kg). The predictive value of granulocyte-monocyte colony-forming cell (GM-CFC) measurements and the value of bone marrow obtained after PBSC collection failure was assessed. PATIENTS AND METHODS: The study group comprised 324 consecutive patients mobilized with granulocyte colony-stimulating factor (G-CSF) and cyclophosphamide (273 patients), G-CSF with other chemotherapy (37 patients), and G-CSF alone (14 patients). Between one and four aphereses were performed. RESULTS: In 51 of 324 patients, there was failure to obtain 1 x 10(6)/kg CD34+ cells. Twenty-three patients had greater than 1 x 10(5)/kg GM-CFC; 22 patients proceeded to high-dose therapy. Neutrophil recovery occurred within 21 days, but platelet independence was delayed (> 28 days) in eight patients. Of 28 patients with less than 1 x 10(5)/kg GM-CFC, six received high-dose therapy with PBSC alone and five had delayed engraftment. Twelve patients with less than 1 x 10(5)/kg GM-CFC received high-dose therapy supported by bone marrow collected after PBSC collection failure. Eleven patients were assessable for engraftment; four patients had slow (> 21 days) or delayed (> 28 days) neutrophil recovery and eight patients had delayed platelet recovery. In the group of patients who received less than 1 x 10(5)/kg GM-CFC, there were five procedure-related deaths. CONCLUSION: This study shows that delayed hematologic recovery is frequent if less than 1 x 10(6)/kg CD34+ cells are infused after high-dose therapy, particularly with GM-CFC less than 1 x 10(5)/kg. The procedure-related mortality in this latter group is high. In most patients whose PBSC collection contains less than 1 x 10(5)/kg GM-CFC, the use of bone marrow cells does not improve engraftment, which suggests that poor PBSC mobilization usually indicates poor marrow function.

Evaluation of clinical scale CD34+ cell purification: experience of 71 immunoaffinity column procedures.

Seventy-one mobilised PBSC collections were subject to CD34+ cell purification using the CEPRATE SC stem cell concentration system. The overall median purity of CD34+ cells was 69% (6-93%). CD34+ cell, and GM-CFC recoveries were 52% (8-107%) and 36% (3-118%). Purity was logarithmically related to the input percentage of CD34+ cells and starting requirements were established of 1% CD34 cell content for optimal purity and a minimum of 2 x 10(6)/kg CD34+ cells to ensure recovery of our minimum engraftment threshold of 1 x 10(6)/kg CD34+ cells. Reduction of the washing steps reduced non-specific cell losses and shortened the procedure but did not affect progenitor cell recovery. Purified CD34+ cells were reinfused following high-dose therapy in 35 patients. The median time to neutrophil recovery of 0.5 x 10(9)/l was 12 (10-23) days and to the attainment of platelet independence was 13 (7-100) days. The risks of delayed platelet recovery were related to the CD34+ cell dose infused and were identical to the risks when non-purified PBSC collections were used. In conclusion, purification of CD34+ cells using the CEPRATE device is reliable and the purified product results in prompt engraftment. The cell losses that occur do however restrict its use in many patients.