New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment.

The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/c^{2}.

First direct limits on lightly ionizing particles with electric charge less than e/6.

While the standard model of particle physics does not include free particles with fractional charge, experimental searches have not ruled out their existence. We report results from the Cryogenic Dark Matter Search (CDMS II) experiment that give the first direct-detection limits for cosmogenically produced relativistic particles with electric charge lower than e/6. A search for tracks in the six stacked detectors of each of two of the CDMS II towers finds no candidates, thereby excluding new parameter space for particles with electric charges between e/6 and e/200.

Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment.

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2.

Search for low-mass weakly interacting massive particles with SuperCDMS.

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30 GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42) cm(2) at 8 GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6 GeV/c(2).

Silicon detector dark matter results from the final exposure of CDMS II.

We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41(-0.08)(+0.20)(stat)(-0.24)(+0.28)(syst). Other known backgrounds from neutrons and 206Pb are limited to <0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7-100 keV for a WIMP of mass 10 GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6 GeV/c2 and WIMP-nucleon cross section of 1.9×10(-41) cm2.

Quantitation of cell-associated borrelial DNA in the blood of Lyme disease patients with erythema migrans.

Bloodstream invasion is an important event in the pathogenesis of the more serious manifestations of Lyme disease. The number of spirochetes in the blood of infected patients, however, has not been determined, and, therefore, it is unknown whether the number of spirochetes can be correlated with particular clinical or laboratory features. This study was designed to measure the level of Borrelia burgdorferi in the plasma of Lyme disease patients and correlate these levels with selected clinical and laboratory findings. Nested and quantitative polymerase chain reaction (qPCR) was employed to detect cell-associated flaB gene DNA in the plasma of untreated early Lyme disease patients with erythema migrans (EM). Twenty-nine (45.3%) of 64 patients had evidence of B. burgdorferi in their plasma by at least one of the PCR methods. For the 22 qPCR-positive patients, the mean number of flaB gene copies per mL of plasma was 4,660, with a range of 414 to 56,000. The number of flaB gene copies did not significantly correlate with any of the clinical, demographic, or laboratory variables assessed. For reasons discussed, we suggest caution in extrapolating an estimate of the number of viable Borrelia in plasma from the observed number of flaB copies.

Results from a low-energy analysis of the CDMS II germanium data.

We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10 GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.

Search for axions with the CDMS experiment.

We report on the first axion search results from the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. An energy threshold of 2 keV for electron-recoil events allows a search for possible solar axion conversion into photons or local galactic axion conversion into electrons in the germanium crystal detectors. The solar axion search sets an upper limit on the Primakov coupling g(agammagamma) of 2.4x10(-9) GeV-1 at the 95% confidence level for an axion mass less than 0.1 keV/c2. This limit benefits from the first precise measurement of the absolute crystal plane orientations in this type of experiment. The galactic axion search analysis sets a world-leading experimental upper limit on the axioelectric coupling g(aee) of 1.4x10(-12) at the 90% confidence level for an axion mass of 2.5 keV/c2.

Increase in size of the pulmonary autograft after the Ross operation in children: growth or dilation?

OBJECTIVE: We sought to assess growth properties of the pulmonary autograft after the Ross operation in children. METHODS: Eight infants with critical aortic stenosis who underwent the Ross operation early in life (median age, 6.4 months) were followed up regarding the possible growth of the autograft. The pulmonary autograft was measured repeatedly by echocardiography during the follow-up, ranging from 6 months to 7 years (median, 5.2 years). Twelve normal children who served as control subjects were similarly followed from 3.9 to 5.8 years (median, 4.9 years). RESULTS: Somatic growth during the follow-up period was significant and was reflected in a doubling of the body surface area, which increased from 0.33 +/- 0.14 m(2) to 0.74 +/- 0.21 m(2). The proximal part of the autograft increased from 13.6 +/- 3.6 mm to 23.3 +/- 3.7 mm (mean +/- SD) and the distal part from 10.5 +/- 2.5 mm to 15.9 +/- 2.8 mm. Growth pattern of the autograft was analyzed by relating measured diameters to predicted normal diameters (ie, Z values). During the first year after the operation, the mean Z value of the proximal autograft increased from 0.2 to 2.2, indicating a more rapid increase than the predicted increase and was also significantly higher than that of the control group (P =.01). After the first year, Z-value changes in patients and control subjects were very similar. CONCLUSIONS: We thus conclude that the pulmonary autograft in the aortic position after the Ross operation does increase in size and that the pattern of this increase is suggestive of passive dilation in the early postoperative period, followed by normal active growth.

Aortic valve replacement with a pulmonary autograft in infants with critical aortic stenosis.

Seven patients with critical aortic stenosis underwent aortic valve replacement with a pulmonary autograft (the Ross operation) between the ages of 5 weeks and 9 months. The operation was considered mandatory for survival because of continued severe heart failure or valve avulsion. Six of the patients had undergone unsuccessful previous palliations, such as commissurotomy, balloon dilation, and transventricular valvotomy, performed singly (n = 1) or in combination (n = 5). The other patient with a severely hypoplastic aortic valve ring underwent the Ross procedure as a primary operation. Two operative deaths occurred. In both cases severe endocardial fibroelastosis was detected at autopsy. One late death 1 year after the operation resulted from progressive hypertrophic cardiomyopathy and pulmonary hypertension. The rest of the patients are doing well, without medications. Apart from trivial regurgitation in two patients, the pulmonary autograft is performing well.

Stepdown single agent antibiotic therapy for the management of the high risk neutropenic adult with hematologic malignancies.

The standard of therapy for the high risk adult neutropenic host being treated with broad spectrum antibiotics for fever has been to continue intravenous antibiotics until neutropenia resolves. We performed a small, limited pilot study to determine if it is safe to switch these patients to oral monotherapy with ciprofloxacin. Ten patients with hematologic malignancies who had < or = 108 granulocytes/mm3 after cytoreductive therapy and were afebrile for at least five days had intravenous antibiotics discontinued and were placed on oral ciprofloxacin. Eight patients were able to be discharged from the hospital and seven were treated without the need for reinstitution of intravenous therapy. Of the three failures, one developed fever with a new bloodstream infection and two developed fever with relapse of leukemia. Patients remained on ciprofloxacin an average of 14.5 days (range 4 to 35 days). Aggregate cost savings for the 10 patients from this approach were estimated to be $11,400 for antibiotics and $88,800 for hospitalization. If corroborated in larger, randomized studies, the use of "stepdown monotherapy" may be a cost effective approach to the management of the stable neutropenic patient.

Vesicular erythema migrans.

BACKGROUND: Lyme disease is the most common vector-borne disease in the United States. The characteristic rash, erythema migrans, is an early sign of the disease. Clinical criteria remain the "gold standard" for diagnosis at this stage of illness. OBSERVATIONS: Five (8%) of 65 patients with erythema migrans seen in a Lyme disease diagnostic center in Westchester County, New York, had a lesion with vesicles. Borrelia burgdorferi was cultured from two of five. In one case the positive culture came from a swab of the blister fluid. CONCLUSIONS: Recognition of erythema migrans and its variants is important, since early treatment of Lyme disease may prevent late complications. Vesicular erythema migrans should be added to the differential diagnosis of inflammatory vesicular rashes in the appropriate clinical setting.

Assessment of the power and height of radial aspheres reported by a computer-assisted keratoscope.

PURPOSE: The two purposes of this study were (a) to assess the accuracy with which a keratoscope, the Topographic Modeling System (TMS-1), calculated the heights and powers of rotationally symmetric, radially aspheric test surfaces and (b) to determine whether the TMS-1 used an axial solution for radius of curvature to determine the power of a sphere that would produce the same semichord as would the test surface on a keratograph. METHODS: The TMS-1 heights and powers were studied for four test surfaces that had radial profiles similar to those of normal corneas. The powers of the surfaces were calculated from the local radius of curvature derived from the surfaces' manufacturing formulas. The heights and powers that would result from an axial solution were calculated in a TMS-1 simulator. TMS-1 data were compared with data from the surfaces' formulas and with data from the simulation. RESULTS: The TMS-1 data were almost identical to the heights and powers calculated from the simulated axial solution. The TMS-1 data were similar to the heights and powers calculated from the mathematical formulas from the apex to 2 mm from the apex but differed by up to 85 microns of height and 10 diopters of power in the periphery. CONCLUSIONS: The TMS-1 appeared to use the axial solution that does not calculate power from local radius of curvature. Clinicians should use caution when inferring corneal shape from power maps based on an axial solution, especially outside the central 2-mm radius of a normal cornea, because such power does not depict corneal curvature.

Height measurement of astigmatic test surfaces by a keratoscope that uses plane geometry surface reconstruction.

PURPOSE: To assess the accuracy with which the Keratron keratoscope (Optikon 2000, Rome, Italy) measured astigmatic test surfaces by a profile reconstruction algorithm within a plane geometry model and to discriminate between error caused by the model and error caused by other factors. METHODS: Height was reported by the Keratron for eight surfaces with central astigmatism ranging from 4 to 16 diopters. A three-dimensional ray tracing simulation produced theoretic reflected ring patterns on which the Keratron's reconstruction algorithm was performed. The Keratron's measurements were compared with the surfaces' formulas and the ray-traced simulations. RESULTS: With a new mathematical filter for smoothing ring data, now part of the Keratron's software, maximum error was 0.47% of the total height and was usually less than 1% of local power for surfaces with 4 diopters of astigmatism. For surfaces with 16 diopters of astigmatism, maximum error was as high as 2.9% of total height and was usually less than 2.5% of local power. The reconstruction algorithm accounted for 40% and 70% of height error, respectively. CONCLUSIONS: The efficacy of keratoscopes cannot be assumed from their design theories but must be tested. Although plane geometry surface reconstruction contributed greatly to total height error, total error was so small that it is unlikely to affect clinical use.

Assessment of radial aspheres by the Arc-step algorithm as implemented by the Keratron keratoscope.

PURPOSE: To assess the accuracy with which the Keratron (Optikon 2000, Rome, Italy) measured rotationally symmetric, radially aspheric test surfaces according to an arc-step profile reconstruction algorithm and to discriminate between error caused by the algorithm and error from other sources. METHODS: Height, local power, and axial power calculated from radius of curvature centered on the instrument's axis were reported by the Keratron for four surfaces that had radial profiles similar to normal corneas. The Keratron profile reconstruction algorithm was simulated by using ray tracing. Keratron measurements were compared with the surfaces' formulas and the ray-traced simulations. RESULTS: The heights reported by the Keratron were within 0.25 microns from the four surfaces at less than 3 mm from the keratoscope axis and generally within 1 micron of the height calculated from the surfaces' formulas. The Keratron's axial powers were within +/- 0.1 diopter of the simulation of the axial solution between 1 and 4 mm of the axis but were greater central to 1 mm and peripheral to 4 mm. The Keratron's local powers were within -0.25 diopters at less than 4 mm from the axis and peripherally were between +1.75 diopters and -0.75 diopter of power calculated from the surface's instantaneous radii of curvature. Height error because of the arc-step algorithm was less than -0.2 micron. CONCLUSIONS: The Keratron's arc-step profile reconstruction algorithm contributed to its ability to measure height more accurately than keratoscopes that use spherically biased algorithms and provided measurement of local power.

Transcutaneous and arterial blood gas monitoring during acute asthmatic symptoms in older children.

The relationship between transcutaneous and arterial blood gases was investigated in 14 children with asthmatic symptoms, aged 7-15 years, before and after the inhalation of salbutamol. The degree of bronchial obstruction was assessed by forced expiratory volume in one second (FEV1) and maximum expiratory flow when 25% of FVC remained to be expelled (MEF25). On average the transcutaneous PO2 (tcPO2) was 1.3 kPa (range, 2.6-0 kPa) lower and the transcutaneous PCO2 was 0.6 kPa (range, 0-1.5 kPa) higher than the corresponding arterial values (P less than 0.01). The difference between arterial and transcutaneous PO2 was the same over the whole range of values studied (7.5-14 kPa). After the inhalation of salbutamol, the relationship between transcutaneous and arterial blood gases was not significantly changed. Changes in transcutaneous PO2 correlated to changes in MEF25 (P less than 0.05), indicating a common denominator, probably the conditions in the peripheral airways. We conclude that the close relationship between transcutaneous and arterial blood gases, even after the inhalation of a beta-2 agonist, indicates that the transcutaneous technique can be used for monitoring acute bronchial obstruction and for evaluating the effects of treatment in children of different ages.

Respiratory resistance and transcutaneous PO2 during histamine provocation in children with bronchial asthma.

Bronchial reactivity was assessed in 66 children with bronchial asthma (aged 8-15 years) by provocation with histamine-HCl during a symptom-free period. A significant bronchial reaction to histamine was defined as a 50% increase in the resistance of the respiratory system (Rrs) determined by the forced oscillation technique. The provocative dose causing a 50% increase in the Rrs (PD50Rrs) was interpolated from the log dose-response curve. The mean PD50Rrs was significantly lower in children with asthma (0.22 mg/mL) compared with a group of healthy children in the same age range (1.55 mg/mL) (P < 0.001). In children with clinically severe asthma, the mean PD50Rrs was lower (0.13 mg/mL) than in children with mild asthma (0.34 mg/mL) (P < 0.001). Transcutaneous PO2 (PtcO2) was monitored in 25 of the children with asthma. In this group the proportion of mild and severe asthma, the baseline lung function variables, and the PD50Rrs were not significantly different from those of the whole group of children. During the reaction, the PtcO2 fell on average by 29% of the baseline value (P < 0.001); in 88% of the children, the fall in PtcO2 was 20% or more of the baseline value. We conclude that histamine provocation tests using the forced oscillation technique and transcutaneous PO2 to assess a bronchial reaction have a good discriminatory capacity for different degrees of clinical severity of asthma in children.

Transcutaneous blood gas monitoring during salbutamol inhalations in young children with acute asthmatic symptoms.

The effect of salbutamol inhalations on transcutaneous blood gases was investigated in 23 children (aged 11 months-2.5 years) with asthmatic symptoms. After one salbutamol inhalation there was a mean increase in transcutaneous PO2 (tcPO2) of 0.5 kPa (P less than 0.01); after a second dose given 30 minutes later, the mean increase was 1.2 kPa (P less than 0.001). The increase in tcPO2 after only one dose of salbutamol was significantly correlated to age (P less than 0.01). No such correlation was observed after a second dose. The overall increase in tcPO2 after two salbutamol inhalations showed a negative correlation to the duration of the current symptomatic period (P less than 0.05). We conclude that salbutamol inhalations have beneficial effects in young children with acute asthmatic symptoms, even below the age of 18 months, provided that an adequate dose reaches the lung and preferably at an early stage of obstruction.

Dark matter search results from the CDMS II experiment.

Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 +/- 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models.

Search for weakly interacting massive particles with the first five-tower data from the cryogenic dark matter search at the soudan underground laboratory.

We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October 2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10;{-44} cm;{2} (4.6x10;{-44} cm;{2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c;{2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c;{2}, and significantly restricts the parameter space for some favored supersymmetric models.