Capturing the Shear and Secondary Compression Waves: High-Frame-Rate Ultrasound Imaging in Saturated Foams.

We experimentally observe the shear and secondary compression waves inside soft porous water-saturated melamine foams by high-frame-rate ultrasound imaging. Both wave speeds are supported by the weak frame of the foam. The first and second compression waves show opposite polarity, as predicted by Biot theory. Our experiments have direct implications for medical imaging: melamine foams exhibit a similar microstructure as lung tissue. In the future, combined shear wave and slow compression wave imaging might provide new means of distinguishing malignant and healthy pulmonary tissue.

Detection of invasive pulmonary aspergillosis in critically ill patients by combined use of conventional culture, galactomannan, 1-3-beta-D-glucan and Aspergillus specific nested polymerase chain reaction in a prospective pilot study.

Invasive pulmonary aspergillosis (IPA) is an emerging and life-threatening infectious disease in patients admitted to the intensive care unit (ICU). Most diagnostic studies are conducted in hematological patients and results cannot readily be transferred to ICU patients lacking classical host factors. In a multicenter, prospective clinical trial including 44 ICU patients, hematological (n = 14) and non-hematological patients (n = 30), concurrent serum and bronchoalveolar lavage (BAL) samples were analyzed by conventional culture, galactomannan (GM), 1-3-beta-D-glucan (BDG) as well as an Aspergillus specific nested polymerase chain reaction (PCR). Nine patients (20%) had putative IPA according to AspICU classification. GM and PCR showed superior performance in BAL with sensitivity/specificity of 56%/94% and 44%/94% compared to 33%/97% and 11%/94% in serum. Despite better sensitivity of 89%, BDG showed poor specificity of only 31% (BAL) and 26% (serum). Combination of GM and PCR (BAL) with BDG (serum) resulted in 100% sensitivity, but also reduced specificity to 23%. Whereas mean GM levels were significantly higher in hematological patients BDG and PCR did not differ between hematological and non-hematological patients. Under present clinical conditions test combinations integrating both BAL and blood samples are advantageous. BDG might best serve as possible indicator for ruling out IPA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01695499. First posted: September 28, 2012, last update posted: May 8, 2017.

ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Intracellular signaling pathways: tyrosine kinase and mTOR inhibitors).

BACKGROUND: The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biologic therapies. AIMS: To review, from an infectious diseases perspective, the safety profile of therapies targeting different intracellular signaling pathways and to suggest preventive recommendations. SOURCES: Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family. CONTENT: Although BCR-ABL tyrosine kinase inhibitors modestly increase the overall risk of infection, dasatinib has been associated with cytomegalovirus and hepatitis B virus reactivation. BRAF/MEK kinase inhibitors do not significantly affect infection susceptibility. The effect of Bruton tyrosine kinase inhibitors (ibrutinib) among patients with B-cell malignancies is difficult to distinguish from that of previous immunosuppression. However, cases of Pneumocystis jirovecii pneumonia (PCP), invasive fungal infection and progressive multifocal leukoencephalopathy have been occasionally reported. Because phosphatidylinositol-3-kinase inhibitors (idelalisib) may predispose to opportunistic infections, anti-Pneumocystis prophylaxis and prevention strategies for cytomegalovirus are recommended. No increased rates of infection have been observed with venetoclax (antiapoptotic protein Bcl-2 inhibitor). Therapy with Janus kinase inhibitors markedly increases the incidence of infection. Pretreatment screening for chronic hepatitis B virus and latent tuberculosis infection must be performed, and anti-Pneumocystis prophylaxis should be considered for patients with additional risk factors. Cancer patients receiving mTOR inhibitors face an increased incidence of overall infection, especially those with additional risk factors (prior therapies or delayed wound healing). IMPLICATIONS: Specific preventive approaches are warranted in view of the increased risk of infection associated with some of the reviewed agents.

Diagnostic Performance of Contrast Enhanced Pulmonary Computed Tomography Angiography for the Detection of Angioinvasive Pulmonary Aspergillosis in Immunocompromised Patients.

Invasive pulmonary aspergillosis (IPA) is one of the major complications in immunocompromised patients. The mainstay of diagnostic imaging is non-enhanced chest-computed-tomography (CT), for which various non-specific signs for IPA have been described. However, contrast-enhanced CT pulmonary angiography (CTPA) has shown promising results, as the vessel occlusion sign (VOS) seems to be more sensitive and specific for IPA in hematologic patients. The aim of this study was to evaluate the diagnostic accuracy of CTPA in a larger cohort including non-hematologic immunocompromised patients. CTPA studies of 78 consecutive immunocompromised patients with proven/probable IPA were analyzed. 45 immunocompromised patients without IPA served as a control group. Diagnostic performance of CTPA-detected VOS and of radiological signs that do not require contrast-media were analyzed. Of 12 evaluable radiological signs, five were found to be significantly associated with IPA. The VOS showed the highest diagnostic performance with a sensitivity of 0.94, specificity of 0.71 and a diagnostic odds-ratio of 36.8. Regression analysis revealed the two strongest independent radiological predictors for IPA to be the VOS and the halo sign. The VOS is highly suggestive for IPA in immunocompromised patients in general. Thus, contrast-enhanced CTPA superior over non-contrast_enhanced chest-CT in patients with suspected IPA.

Diagnosis of invasive fungal infections in haematological patients by combined use of galactomannan, 1,3-ß-D-glucan, Aspergillus PCR, multifungal DNA-microarray, and Aspergillus azole resistance PCRs in blood and bronchoalveolar lavage samples: results of a prospective multicentre study.

High mortality rates of invasive fungal disease (IFD), especially invasive aspergillosis (IA), in immunocompromised haematological patients and current diagnostic limitations require improvement of detection of fungal pathogens by defining the optimal use of biomarkers and clinical samples. Concurrent bronchoalveolar lavage (BAL) and peripheral blood samples of 99 haematological patients with suspected IFD were investigated within a multicentre prospective study. Diagnostic performance of a galactomannan (GM) enzyme immune assay (EIA), a 1,3-ß-D-glucan assay (BDG), an Aspergillus PCR, and a multifungal DNA-microarray (Chip) alone or in combination were calculated. IFD were classified as proven (n=3), probable (n=34), possible (n=33), and no IFD (n=29) according to EORTC/MSG criteria. GM, PCR, and Chip showed superior diagnostic performance in BAL than in blood, whereas specificity of BDG in BAL was poor (48% (14/29)). The combination of GM (BAL) with BDG (blood) showed sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and DOR (diagnostic odds ratio) of 92% (34/37), 93% (27/29), 94%, 90%, and 153.0, respectively. Combining GM (BAL) with PCR (BAL) showed convincing diagnostic potential for diagnosing IA with sensitivity, specificity, PPV, NPV, and DOR of 85% (17/20), 97% (28/29), 94%, 90%, and 158.7. Addition of the DNA-microarray resulted in further detection of two mucormycetes infections. In 1 out of 15 Aspergillus DNA-positive samples a triazole resistance-mediating Cyp51A mutation was found. Combination of biomarkers is superior to their sole use in diagnosing IFD, particularly IA. Integrating blood and BAL samples into a diagnostic algorithm is an advantageous approach.

Allogeneic hematopoietic cell transplantation without fluconazole and fluoroquinolone prophylaxis.

Fluoroquinolone (FQ) and fluconazole prophylaxis is recommended for patients undergoing allogeneic hematopoietic cell transplantation (alloHCT). However, due to an uncertain scientific basis and the increasing emergence of resistant germs, this policy should be questioned. Therefore, FQ and fluconazole prophylaxis was omitted in alloHCT at our center. In this retrospective analysis, all consecutive patients (n = 63) who underwent first alloHCT at our institution from September 2010 to September 2013 were included. Patients neither received FQ nor fluconazole prophylaxis. Day 100 mortality, incidence of febrile neutropenia, bacterial infections, and invasive fungal diseases (IFD) were assessed. Sixteen patients who started conditioning under antimicrobial treatment/prophylaxis due to pre-existing neutropenia (3/16), IFD (12/16), or aortic valve replacement (1/16) were excluded from the analysis. Finally, 47 patients were transplanted without prophylaxis as intended. Day 100 mortality was 9 %. Febrile neutropenia occurred in 62 % (29/47); 17/47 patients (36 %) experienced a blood stream infection (BSI) with detection of Gram-positive bacteria in 14 patients, Gram-negative bacteria in five patients, and candida in one patient, respectively. Coagulase-negative staphylococci were the most frequently isolated Gram-positive bacteria; 12/21 isolated Gram-positive and 3/6 Gram-negative bacteria were FQ resistant. In 21 % (10/47) of the patients, IFD (1x proven, 1x probable, and 8x possible) were diagnosed. To conclude, all three criteria, day 100 mortality, the incidence of IFD, and BSI, are in the range of published data for patients transplanted with FQ and fluconazole prophylaxis. These data demonstrate that alloHCT is feasible without FQ and fluconazole prophylaxis.

Identification of invasive fungal diseases in immunocompromised patients by combining an Aspergillus specific PCR with a multifungal DNA-microarray from primary clinical samples.

The increasing incidence of invasive fungal diseases (IFD), most of all invasive aspergillosis (IA) in immunocompromised patients emphasises the need to improve the diagnostic tools for detection of fungal pathogens. We investigated the diagnostic performance of a multifungal DNA-microarray detecting 15 different fungi [Aspergillus, Candida, Fusarium, Mucor, Rhizopus, Scedosporium and Trichosporon species (spp.)] in addition to an Aspergillus specific polymerase chain reaction (PCR) assay. Biopsies, bronchoalveolar lavage and peripheral blood samples of 133 immunocompromised patients (pts) were investigated by a multifungal DNA-microarray as well as a nested Aspergillus specific PCR assay. Patients had proven (n = 18), probable (n = 29), possible (n = 48) and no IFD (n = 38) and were mostly under antifungal therapy at the time of sampling. The results were compared to culture, histopathology, imaging and serology, respectively. For the non-Aspergillus IFD the microarray analysis yielded in all samples a sensitivity of 64% and a specificity of 80%. Best results for the detection of all IFD were achieved by combining DNA-microarray and Aspergillus specific PCR in biopsy samples (sensitivity 79%; specificity 71%). The molecular assays in combination identify genomic DNA of fungal pathogens and may improve identification of causative pathogens of IFD and help overcoming the diagnostic uncertainty of culture and/or histopathology findings, even during antifungal therapy.

Persistence with opioid treatment in Germany in patients suffering from chronic non-malignant or cancer pain.

BACKGROUND: The aim of the present study was to assess factors influencing opioid persistence in a large patient cohort of 32,158 patients receiving opioid treatment for either chronic non-malignant or cancer pain. METHODS: Data from 32,158 patients with first-time prescription of an opioid in the timeframe from January 2009 until December 2013 treated in 115 orthopedic, 104 neurological and 1129 general practitioner practices were retrospectively analyzed (Disease Analyzer database Germany). A Cox proportional hazards regression model was used to estimate the relationship between non-persistence and the demographic and clinical variables described previously for a maximum follow-up period of 1 year. RESULTS: After 1 year of follow-up, 69% of patients treated with opioids had stopped medication intake (refill gap of 90 days). There was a significantly increased risk of treatment discontinuation for younger patients (<40 years HR: 1.45; 41-50 years HR: 1.37; 51-60 years HR: 1.23; 61-70 years HR: 1.22) as compared with patients aged >70. Cancer pain was associated with a significantly lower risk of therapy discontinuation (HR: 0.69), whereas persistence was considerably less probable for diagnoses such as various kinds of back pain (HR: 1.26), osteoarthritis (HR: 1.14) and spondylarthritis (HR: 1.09). Chronic comorbidities such as diabetes, hypertension, heart insufficiency, and dementia were associated with a decreased risk of treatment discontinuation. CONCLUSION: Our study showed that persistence with opioid treatment is associated with cancer pain, chronic comorbidities and depression, while younger age and chronic non-malignant pain (especially due to back pain) increase the possibility of opioid discontinuation. It will be the task of future studies to assess reasons for opioid discontinuation in more detail, which is an important step towards improving patient care and health outcomes.

Assessment of Aspergillus-specific PCR as a screening method for invasive aspergillosis in paediatric cancer patients and allogeneic haematopoietic stem cell recipients with suspected infections.

Invasive aspergillosis (IA) remains difficult to diagnose in immunocompromised patients, because diagnostic EORTC/MSG criteria are often not met. As biomarkers might elucidate the pathogen, we analysed the performance of an Aspergillus PCR assay in blood for diagnosis of IA in immunocompromised paediatric patients with suspected infections. Ninety-five haemato-oncological paediatric patients were included over a period of 3 years, the underlying diseases consisting of acute leukaemia, solid tumours, non-malignant immunocompromising disorders and haematopoietic stem cell transplantation recipients. We retrospectively analysed 253 consecutive episodes of suspected infections. Thirty-eight patients had possible IA, none of the patients fulfilled EORTC/MSG criteria of probable/proven IA. PCR positivity was observed in 97/967 analyses. Sensitivity, specificity, positive and negative predictive value of the PCR per episode were 34%, 78%, 31% and 81% using possible IA as endpoint. Taken together, an undirected blood screening by Aspergillus-specific PCR is of little diagnostic value in a heterogenous paediatric patient cohort. Harnessing PCR for diagnosis of IA should thus be focused on blood analyses of more homogenous high-risk patients and/or analyses of bronchoalveolar lavage, tissue or cerebrospinal fluid specimens.

Performance of galactomannan, beta-d-glucan, Aspergillus lateral-flow device, conventional culture, and PCR tests with bronchoalveolar lavage fluid for diagnosis of invasive pulmonary aspergillosis.

Galactomannan detection in bronchoalveolar lavage (BAL) fluid samples (GM test) is currently considered the gold standard test for diagnosing invasive pulmonary aspergillosis (IPA). The limitations, however, are the various turnaround times and availability of testing. We compared the performance of GM testing with that of conventional culture, an Aspergillus lateral-flow-device (LFD) test, a beta-d-glucan (BDG) test, and an Aspergillus PCR assay by using BAL fluid samples from immunocompromised patients. A total of 78 BAL fluid samples from 78 patients at risk for IPA (74 samples from Graz and 4 from Mannheim) collected between December 2012 and May 2013 at two university hospitals in Austria and Germany were included. Three patients had proven IPA, 14 probable IPA, and 17 possible IPA, and 44 patients had no IPA. The diagnostic accuracies of the different methods for probable/proven IPA were evaluated. The diagnostic odds ratios were the highest for the GM, PCR, and LFD tests. The sensitivities for the four methods (except culture) were between 70 and 88%. The combination of the GM (cutoff optical density index [ODI], >1.0) and LFD tests increased the sensitivity to 94%, while the combination of the GM test (>1.0) and PCR resulted in 100% sensitivity (specificity for probable/proven IPA, 95 to 98%). The performance of conventional culture was limited by low sensitivity, while that of the BDG test was limited by low specificity. We evaluated established and novel diagnostic methods for IPA and found that the Aspergillus PCR, LFD, and GM tests were the most useful methods for diagnosing the disease by using BAL fluid samples. In particular, the combination of the GM test and PCR or, if PCR is not available, the LFD test, allows for sensitive and specific diagnosis of IPA.

Aspergillus PCR-based investigation of fresh tissue and effusion samples in patients with suspected invasive Aspergillosis enhances diagnostic capabilities.

Although it is a severe complication in immunocompromised patients, diagnosing invasive fungal disease (IFD), especially invasive aspergillosis (IA), remains difficult. In certain clinical scenarios, examining tissue samples for identification of the infectious organism becomes important. As culture-based methods rarely yield results, the performance of an Aspergillus-specific nested PCR in fresh tissue or pleural effusion samples was evaluated. Fresh tissue (n = 59) and effusion (n = 47) specimens from 79 immunocompromised patients were subjected to an Aspergillus-specific PCR assay. Twenty-six patients had proven (n = 20) or probable (n = 6) IFD, according to the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) criteria, while the remaining patients were classified as having either possible IFD (n = 30) or no IFD (n = 23). IA was identified as the underlying IFD in 21/26 proven/probable cases. PCR positivity was observed for 18/21 proven/probable and 6 possible IA cases; cases classified as no IA did not show positive signals. Patients with proven IFD (n = 5) with cultures positive for non-Aspergillus molds also had negative Aspergillus PCR results. Aspergillus PCR performance analysis yielded sensitivity and specificity values of 86% (95% confidence interval [CI], 65% to 95%) and 100% (95% CI, 86% to 100%), respectively, thus leading to a diagnostic odds ratio of >200. In this analysis, good diagnostic performance of the PCR assay for detection of IA was observed for tissue samples, while effusion samples showed lower sensitivity rates. PCR testing represents a complementary tool; a positive PCR result strengthens the likelihood of IA, whereas IA seems unlikely in cases with negative results but findings could indicate non-Aspergillus IFD. Thus, PCR testing of these specimens enhances the diagnostic capabilities.

Mapping leakage currents in a nanostructure fabricated via local anodic oxidation.

The functionality of nanostructures fabricated via local anodic oxidation is limited by undesired leakage currents. We use low-temperature scanning gate microscopy to pin down the spatial position where leakage currents are most likely to occur. We show that leakage currents do not flow homogeneously along the complete barrier but at distinct weak points such as crossings of two oxide lines. These findings can be used to improve the design of such nanostructures.

Effect of microwaves on the current-phase relation of superconductor-normal-metal-superconductor josephson junctions.

We investigate the current-phase relation (CPR) of long diffusive superconductor-normal-metal-superconductor (Nb/Ag/Nb) Josephson junctions in thermodynamic equilibrium and under microwave irradiation. While in equilibrium good agreement with the predictions of quasiclassical theory is found, we observe that the shape of the CPR can be strongly affected by microwave irradiation. Close to a Josephson-phase difference phi approximately pi, the supercurrent can be strongly suppressed when increasing the rf power. Our results can be understood in terms of microwave excitation of low-lying Andreev bound states across the minigap in the junction. In the frequency interval studied, this mechanism becomes important, when the minigap closes at phi approximately pi.

Dephasing in (Ga,Mn)As nanowires and rings.

To understand quantum mechanical transport in a ferromagnetic semiconductor, the knowledge of basic material properties such as the phase coherence length and corresponding dephasing mechanism are indispensable ingredients. The lack of observable quantum phenomena has prevented experimental access to these quantities so far. Here we report the observations of universal conductance fluctuations in ferromagnetic (Ga,Mn)As. The analysis of the length and temperature dependence of the fluctuations reveals a T(-1) dependence of the dephasing time.

Low-dose liposomal amphotericin B in the prevention of invasive fungal infections in patients with prolonged neutropenia: results from a randomized, single-center trial.

BACKGROUND: We performed a prospective, randomized, open-label trial to evaluate the efficacy of low-dose liposomal amphotericin B (L-AmB) to reduce the incidence of invasive fungal infections (IFI) in patients with hematological malignancies and prolonged neutropenia (>10 days) following intensive chemotherapy. PATIENTS AND METHODS: In 219 neutropenic episodes (NE) of 132 patients randomization was performed. Patients received either 50 mg L-AmB every other day (arm A) or no systemic antifungal prophylaxis (arm B). RESULTS: In the first NE of each patient the incidence of proven or probable IFI (primary end point) was five of 75 patients (6.7%) in arm A and 20 of 57 patients (35%) in arm B (P=0.001). Invasive aspergillosis occurred less frequently in patients receiving L-AmB-prophylaxis (P=0.0057), whereas the reduction of invasive candidiasis did not reach statistical significance (P=0.0655). In all NE the incidence of IFI was five of 110 NE (4.6%) in arm A versus 22 of 109 NE (20.2%) in arm B (P<0.01). Adverse events, possibly related to L-AmB, were observed in five NE (4.6%) and L-AmB was discontinued in three NE (2.8%). No grade 3 or 4 toxicities were observed. CONCLUSIONS: Antifungal prophylaxis with low-dose L-AmB proved to be feasible and effective in our trial.

Probing a Kondo-correlated quantum dot with spin spectroscopy.

We investigate the Kondo effect and spin blockade observed in a many-electron quantum dot and study the magnetic field dependence. At lower fields, a pronounced Kondo effect is found, which is replaced by the spin blockade at higher fields. In an intermediate regime, both effects are visible. We make use of this combined effect to gain information about the internal spin configuration of our quantum dot. We find that the data cannot be explained assuming regular filling of electronic orbitals. Instead, spin polarized filling seems to be probable.

Spatially resolved manipulation of single electrons in quantum dots using a scanned probe.

The scanning metallic tip of a scanning force microscope was coupled capacitively to electrons confined in a lithographically defined gate-tunable quantum dot at a temperature of 300 mK. Single electrons were made to hop on or off the dot by moving the tip or by changing the tip bias voltage owing to the Coulomb-blockade effect. Spatial images of conductance resonances map the interaction potential between the tip and individual electronic quantum dot states. Under certain conditions this interaction is found to contain a tip-voltage induced and a tip-voltage-independent contribution.

Spontaneous supercurrent induced by ferromagnetic pi junctions.

We present magnetization measurements of mesoscopic superconducting niobium loops containing a ferromagnetic (PdNi) pi junction. The loops are prepared on top of the active area of a micro-Hall sensor based on high mobility GaAs/AlGaAs heterostructures. We observe asymmetric switching of the loop between different magnetization states when reversing the sweep direction of the magnetic field. This provides evidence for a spontaneous current induced by the intrinsic phase shift of the pi junction. In addition, the presence of the spontaneous current near zero applied field is directly revealed by an increase of the magnetic moment with decreasing temperature, which results in half integer flux quantization in the loop at low temperatures.