Transcranial focused ultrasound for the treatment of tremor: A preliminary case series

BACKGROUND

Essential tremor (ET) can be debilitating. Treatments for ET include beta-blockers and surgical interventions. Low-intensity focused ultrasound (LIFU) may offer an office-based non-invasive alternative.

OBJECTIVE

This pilot open label clinical trial explores safety, feasibility, and potential efficacy of LIFU in treatment of ET.

METHODS

We report outcomes from the first 10 participants in this IRB-approved trial of LIFU for treatment of ET. The ventral intermediate nucleus of the thalamus (Vim) was targeted using structural and functional MRI. Participants underwent eight 10-min sessions of LIFU targeting the contralateral (Vim) to the most affected hand. Safety was closely monitored; Global Rating of Change (GRC) and The Essential Tremor Rating Scale (TETRAS) scores were collected.

RESULTS

No adverse effects were reported. Eight participants reported a GRC ≥2. TETRAS performance subscale demonstrated clinically significant improvement in all participants.

CONCLUSION

Preliminary findings support LIFU's safety and feasibility. The potential efficacy encourages additional sham-controlled studies.

Use of transcranial low-intensity focused ultrasound for targeted delivery of stem cell-derived exosomes to the brain

The blood-brain barrier (BBB) presents a significant challenge for targeted drug delivery. A proposed method to improve drug delivery across the BBB is focused ultrasound (fUS), which delivers ultrasound waves to a targeted location in the brain and is hypothesized to open the BBB. Furthermore, stem cell-derived exosomes have been suggested as a possible anti-inflammatory molecule that may have neural benefits, if able to pass the BBB. In the present study, transcranial low-intensity focused ultrasound (LIFU), without the use of intravenous microbubbles, was assessed for both (1) its ability to influence the BBB, as well as (2) its ability to increase the localization of intravenously administered small molecules to a specific region in the brain. In vivo rat studies were conducted with a rodent-customized 2 MHz LIFU probe (peak pressure = 1.5 MPa), and injection of labeled stem cell-derived exosomes. The results suggested that LIFU (without microbubbles) did not appear to open the BBB after exposure times of 20, 40, or 60 min; instead, there appeared to be an increase in transcytosis of the dextran tracer. Furthermore, the imaging results of the exosome study showed an increase in exosome localization in the right hippocampus following 60 min of targeted LIFU.

Comparative genomic analyses of multiple backcross mouse populations suggest SGCG as a novel potential obesity-modifier gene

To nominate novel disease genes for obesity and type 2 diabetes (T2D), we recently generated two mouse backcross populations of the T2D-susceptible New Zealand Obese (NZO/HI) mouse strain and two genetically different, lean and T2D-resistant strains, 129P2/OlaHsd and C3HeB/FeJ. Comparative linkage analysis of our two female backcross populations identified seven novel body fat-associated quantitative trait loci (QTL). Only the locus Nbw14 (NZO body weight on chromosome 14) showed linkage to obesity-related traits in both backcross populations, indicating that the causal gene variant is likely specific for the NZO strain as NZO allele carriers in both crosses displayed elevated body weight and fat mass. To identify candidate genes for Nbw14, we used a combined approach of gene expression and haplotype analysis to filter for NZO-specific gene variants in gonadal white adipose tissue (gWAT), defined as the main QTL-target tissue. Only two genes, Arl11 and Sgcg, fulfilled our candidate criteria. In addition, expression QTL analysis revealed cis-signals for both genes within the Nbw14 locus. Moreover, retroviral overexpression of Sgcg in 3 T3-L1 adipocytes resulted in increased insulin-stimulated glucose uptake. In humans, mRNA levels of SGCG correlated with BMI and body fat mass exclusively in diabetic subjects, suggesting that SGCG may present a novel marker for metabolically unhealthy obesity. In conclusion, our comparative-cross analysis could substantially improve the mapping resolution of the obesity locus Nbw14. Future studies will shine light on the mechanism by which Sgcg may protect from the development of obesity.

Nudix hydrolase NUDT19 regulates mitochondrial function and ATP production in murine hepatocytes

Changes in intracellular CoA levels are known to contribute to the development of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes (T2D) in human and rodents. However, the underlying genetic basis is still poorly understood. Due to their diverse susceptibility towards metabolic diseases, mouse inbred strains have been proven to serve as powerful tools for the identification of novel genetic factors that underlie the pathophysiology of NAFLD and diabetes. Transcriptome analysis of mouse liver samples revealed the nucleoside diphosphate linked moiety X-type motif Nudt19 as novel candidate gene responsible for NAFLD and T2D development. Knockdown (KD) of Nudt19 increased mitochondrial and glycolytic ATP production rates in Hepa 1-6 cells by 41% and 10%, respectively. The enforced utilization of glutamine or fatty acids as energy substrate reduced uncoupled respiration by 41% and 47%, respectively, in non-target (NT) siRNA transfected cells. This reduction was prevented upon Nudt19 KD. Furthermore, incubation with palmitate or oleate respectively increased mitochondrial ATP production by 31% and 20%, and uncoupled respiration by 23% and 30% in Nudt19 KD cells, but not in NT cells. The enhanced fatty acid oxidation in Nudt19 KD cells was accompanied by a 1.3-fold increased abundance of Pdk4. This study is the first to describe Nudt19 as regulator of hepatic lipid metabolism and potential mediator of NAFLD and T2D development.

Femtosecond Transfer and Manipulation of Persistent Hot-Trion Coherence in a Single CdSe/ZnSe Quantum Dot

Ultrafast transmission changes around the fundamental trion resonance are studied after exciting a p-shell exciton in a negatively charged II-VI quantum dot. The biexcitonic induced absorption reveals quantum beats between hot-trion states at 133 GHz. While interband dephasing is dominated by relaxation of the P-shell hole within 390 fs, trionic coherence remains stored in the spin system for 85 ps due to Pauli blocking of the triplet electron. The complex spectrotemporal evolution of transmission is explained analytically by solving the Maxwell-Liouville equations. Pump and probe polarizations provide full control over amplitude and phase of the quantum beats.

Phonon-Induced Enhancement of Photon Entanglement in Quantum Dot-Cavity Systems

We report on simulations of the degree of polarization entanglement of photon pairs simultaneously emitted from a quantum dot-cavity system that demand revisiting the role of phonons. Since coherence is a fundamental precondition for entanglement and phonons are known to be a major source of decoherence, it seems unavoidable that phonons can only degrade entanglement. In contrast, we demonstrate that phonons can cause a degree of entanglement that even surpasses the corresponding value for the phonon-free case. In particular, we consider the situation of comparatively small biexciton binding energies and either finite exciton or cavity mode splitting. In both cases, combinations of the splitting and the dot-cavity coupling strength are found where the entanglement exhibits a nonmonotonic temperature dependence which enables entanglement above the phonon-free level in a finite parameter range. This unusual behavior can be explained by phonon-induced renormalizations of the dot-cavity coupling g in combination with a nonmonotonic dependence of the entanglement on g that is present already without phonons.

Effective detection of spatio-temporal carrier dynamics by carrier capture

The spatio-temporal dynamics of electrons moving in a 2D plane is challenging to detect when the required resolution shrinks simultaneously to nanometer length and subpicosecond time scale. We propose a detection scheme relying on phonon-induced carrier capture from 2D unbound states into the bound states of an embedded quantum dot. This capture process happens locally and here we explore if this locality is sufficient to use the carrier capture process as detection of the ultrafast diffraction of electrons from an obstacle in the 2D plane. As an example we consider an electronic wave packet traveling in a semiconducting monolayer of the transition metal dichalcogenide MoSe₂, and we study the scattering-induced dynamics using a single particle Lindblad approach. Our results offer a new way to high resolution detection of the spatio-temporal carrier dynamics.

Influence of patient and tumor characteristics on early therapy persistence with letrozole in postmenopausal women with early breast cancer: results of the prospective Evaluate-TM study with 3941 patients

Background

Patients' compliance and persistence with endocrine treatment has a significant effect on the prognosis in early breast cancer (EBC). The purpose of this analysis was to identify possible reasons for non-persistence, defined as premature cessation of therapy, on the basis of patient and tumor characteristics in individuals receiving adjuvant treatment with letrozole.

Patients and methods

The EvAluate-TM study is a prospective, multicenter, noninterventional study in which treatment with the aromatase inhibitor letrozole was evaluated in postmenopausal women with hormone receptor-positive EBC in the early therapy phase. Treatment persistence was evaluated at two pre-specified study visits after 6 and 12 months. As a measure of early therapy persistence the time from the start to the end of treatment (TTEOT) was analyzed. Cox regression analyses were carried out to identify patient characteristics and tumor characteristics predicting TTEOT.

Results

Out of the total population of 3941 patients with EBC, 540 (13.7%) events involving treatment cessation unrelated to disease progression were observed. This was due to drug-related toxicity in the majority of cases (73.5%). Persistence rates were 92.2%, 86.9%, and 86.3% after 6, 12, and 15 months, respectively. The main factors influencing premature treatment discontinuation were older age [hazard ratio (HR) 1.02/year], comorbidities (HR 1.06 per comorbidity), low body mass index, and lower tumor grade (HR 0.85 per grade unit).

Conclusion

These results support the view that older, multimorbid patients with low tumor grade and low body mass index are at the greatest risk for treatment discontinuation and might benefit from compliance and support programs.

Delayed nitrate dispersion within a coastal aquifer provides constraints on land-use evolution and nitrate contamination in the past

Identifying sources of anthropogenic pollution, and assessing the fate and residence time of pollutants in aquifers is important for the management of groundwater resources, and the ecological health of groundwater dependent ecosystems. This study investigates anthropogenic contamination in the shallow alluvial aquifer of the Marana-Casinca, hydraulically connected to the Biguglia lagoon (Corsica, France). A multi-tracer approach, combining geochemical and environmental isotopic data (δ¹⁸O-H₂O, δ²H-H₂O, ³H, δ¹⁵N-NO₃^-, δ¹⁸O-NO₃^-, δ¹¹B), and groundwater residence-time tracers (³H and CFCs) was carried out in 2016, and integrated with a study of land use evolution in the catchment during the last century. Groundwater NO₃^- concentrations, ranged between 2 mg/L and up to 30 mg/L, displaying the degradation of groundwater quality induced by anthropogenic activities (agricultural activities). Comparatively high δ¹⁵N-NO₃^- values (up to 19.7‰) in combination with δ¹¹B values that were significantly lower (between 23‰ and 26‰) than the seawater background are indicative of sewage contamination. The ongoing deterioration of groundwater quality can be attributed to the uncontrolled urbanization development all over the alluvial plain, with numerous sewage leakages from the sanitation network and private sewage systems. Integration of contaminant and water-residence time data revealed a progressive accumulation of pollutants with time in the groundwater, particularly in areas with major anthropogenic pressure and slow dynamic groundwater flow. Our approach provides time-dependent insight into nitrogen pollution in the studied aquifer over the past decades, revealing a systematic change in the dominant NO₃^- source, from agricultural to sewage contamination. Yet, today's low groundwater quality is to large parts due to legacy pollution from land-use practices several decades ago, underlining the poor self-remediating capacity of this hydrosystem. Our results can be taken as warning that groundwater pollution that happened in the recent past, or today, may have dire impacts on the quality of groundwater-dependent ecosystems in the future.

Circulating plasma phospholipid fatty acids and risk of pancreatic cancer in a large European cohort

There are both limited and conflicting data on the role of dietary fat and specific fatty acids in the development of pancreatic cancer. In this study, we investigated the association between plasma phospholipid fatty acids and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The fatty acid composition was measured by gas chromatography in plasma samples collected at recruitment from375 incident pancreatic cancer cases and375 matched controls. Associations of specific fatty acids with pancreatic cancer risk were evaluated using multivariable conditional logistic regression models with adjustment for established pancreatic cancer risk factors. Statistically significant inverse associations were found between pancreatic cancer incidence and levels of heptadecanoic acid (ORT3-T1 [odds ratio for highest versus lowest tertile] =0.63; 95%CI[confidence interval] = 0.41-0.98; ptrend = 0.036), n-3 polyunsaturated α-linolenic acid (ORT3-T1 = 0.60; 95%CI = 0.39-0.92; ptrend = 0.02) and docosapentaenoic acid (ORT3-T1 = 0.52; 95%CI = 0.32-0.85; ptrend = 0.008). Industrial trans-fatty acids were positively associated with pancreatic cancer risk among men (ORT3-T1 = 3.00; 95%CI = 1.13-7.99; ptrend = 0.029), while conjugated linoleic acids were inversely related to pancreatic cancer among women only (ORT3-T1 = 0.37; 95%CI = 0.17-0.81; ptrend = 0.008). Among current smokers, the long-chain n-6/n-3 polyunsaturated fatty acids ratio was positively associated with pancreatic cancer risk (ORT3-T1 = 3.40; 95%CI = 1.39-8.34; ptrend = 0.007). Results were robust to a range of sensitivity analyses. Our findings suggest that higher circulating levels of saturated fatty acids with an odd number of carbon atoms and n-3 polyunsaturated fatty acids may be related to lower risk of pancreatic cancer. The influence of some fatty acids on the development of pancreatic cancer may be sex-specific and modulated by smoking.

A life cycle assessment of liquid pig manure transport in line with EU regulations: A case study from Germany

The transport of excess manure to crop farming systems is a core measure of livestock farmers to comply with environmental regulations like the EU Nitrates Directive. The German implementation of the directive has recently been revised and will lead to a distinct increase of manure transport. We quantify the environmental impact of 1 m³ of pig manure excreted in scenarios with and without manure transport by life cycle assessment, focusing on farming systems in North-West Germany. Furthermore, we assess how the environmental impact is linked to the regulation which is causing the transport. Compared to a reference scenario without transport, manure transport lowers all assessed impact categories and no trade-off between environmental impacts is found. Major reductions are realized for global warming (39%), freshwater (61%) and marine eutrophication (54%) as well as particulate matter formation (10%). Furthermore, the depletion of fossil fuels and phosphate is lowered. Reductions are mainly caused by an increase of nutrient use efficiency and the savings in chemical fertilizer. However, in a scenario where manure transport is caused by strict regulations regarding phosphate, needed nitrogen leaves the exporting farm likewise and chemical fertilizer use rises at the exporting farm. Caused by the increased fertilizer use, the positive environmental effect of manure transport diminishes, even leading to a rise of fossil fuel depletion by 20% and slight rise of global warming potential by 3%. However, we find that the use of lorries which combine manure and grain transport and, thereby, reduce empty drives, can prevent this trade-off. Our results show the potential of manure transport to reduce the environmental burden caused by the geographical concentration of livestock production. However, the impact of manure transport on global warming and fossil fuel depletion highly depends on the transport distance. Agronomic measures are needed to prevent the increase of chemical N fertilizer use on the exporting farms and policy makers should be aware of possible trade-offs between strict regulations regarding phosphorus and fossil fuel depletion.

Influence of side-effects on early therapy persistence with letrozole in post-menopausal patients with early breast cancer: Results of the prospective EvAluate-TM study

BACKGROUND

Endocrine treatment (ET) with an aromatase inhibitor (AI) is the treatment of choice in post-menopausal patients with hormone receptor-positive early breast cancer (EBC). However, adverse events (AEs) often lead to treatment discontinuation. This analysis aimed to identify side-effects that lead to patients failing to persist with letrozole treatment.

PATIENTS AND METHODS

Post-menopausal hormone receptor-positive EBC patients starting ET with letrozole were enroled in EvAluate-TM, a non-interventional study. Information regarding treatment compliance and persistence was gathered in months 6 and 12. Persistence was defined as the time from 30 d after the start to the end of treatment. The influence on persistence of musculoskeletal syndrome, menopausal disorder, sleep disorder and other AEs within the first 30 d was analysed using Cox regression analyses.

RESULTS

Among 3887 patients analysed, the persistence rate after 12 months was >85%. In all, 568 patients (14.6%) discontinued the treatment, 358 of whom (63.0%) did so only because of side-effects. The main AEs influencing persistence were musculoskeletal symptoms (hazard ratio [HR] 2.55; 95% confidence interval [CI], 1.90-3.42), sleep disorders (HR 1.95; 95% CI, 1.41-2.70) and other AEs (HR 2.03; 95% CI, 1.51-2.73). Menopausal disorder was not associated with non-persistence (HR 1.17; 95% CI, 0.74-1.84).

CONCLUSIONS

These results suggest that side-effects of AIs such as musculoskeletal syndrome and sleep disorder lead to ET discontinuation within the first treatment year in significant numbers of EBC patients. Compliance programmes adapted for subgroups that are at risk for early non-persistence might help to ensure the recommended therapy duration.

CLINICAL TRIALS NUMBER

CFEM345DDE19.

Picosecond Control of Quantum Dot Laser Emission by Coherent Phonons

A picosecond acoustic pulse can be used to control the lasing emission from semiconductor nanostructures by shifting their electronic transitions. When the active medium, here an ensemble of (In,Ga)As quantum dots, is shifted into or out of resonance with the cavity mode, a large enhancement or suppression of the lasing emission can dynamically be achieved. Most interesting, even in the case when gain medium and cavity mode are in resonance, we observe an enhancement of the lasing due to shaking by coherent phonons. In order to understand the interactions of the nonlinearly coupled photon-exciton-phonon subsystems, we develop a semiclassical model and find an excellent agreement between theory and experiment.

Stationary Phonon Squeezing by Optical Polaron Excitation

We demonstrate that a stationary squeezed phonon state can be prepared by a pulsed optical excitation of a semiconductor quantum well. Unlike previously discussed scenarios for generating squeezed phonons, the corresponding uncertainties become stationary after the excitation and do not oscillate in time. The effect is caused by two-phonon correlations within the excited polaron. We demonstrate by quantum kinetic simulations and by a perturbation analysis that the energetically lowest polaron state comprises two-phonon correlations which, after the pulse, result in an uncertainty of the lattice momentum that is continuously lower than in the ground state of the semiconductor. The simulations show the dynamics of the polaron formation process and the resulting time-dependent lattice uncertainties.

Evidence for a Strong Topological Insulator Phase in ZrTe_{5}

The complex electronic properties of ZrTe_{5} have recently stimulated in-depth investigations that assigned this material to either a topological insulator or a 3D Dirac semimetal phase. Here we report a comprehensive experimental and theoretical study of both electronic and structural properties of ZrTe_{5}, revealing that the bulk material is a strong topological insulator (STI). By means of angle-resolved photoelectron spectroscopy, we identify at the top of the valence band both a surface and a bulk state. The dispersion of these bands is well captured by ab initio calculations for the STI case, for the specific interlayer distance measured in our x-ray diffraction study. Furthermore, these findings are supported by scanning tunneling spectroscopy revealing the metallic character of the sample surface, thus confirming the strong topological nature of ZrTe_{5}.

Test-retest reliability of high angular resolution diffusion imaging acquisition within medial temporal lobe connections assessed via tract based spatial statistics, probabilistic tractography and a novel graph theory metric

This study examined the reliability of high angular resolution diffusion tensor imaging (HARDI) data collected on a single individual across several sessions using the same scanner. HARDI data was acquired for one healthy adult male at the same time of day on ten separate days across a one-month period. Environmental factors (e.g. temperature) were controlled across scanning sessions. Tract Based Spatial Statistics (TBSS) was used to assess session-to-session variability in measures of diffusion, fractional anisotropy (FA) and mean diffusivity (MD). To address reliability within specific structures of the medial temporal lobe (MTL; the focus of an ongoing investigation), probabilistic tractography segmented the Entorhinal cortex (ERc) based on connections with Hippocampus (HC), Perirhinal (PRc) and Parahippocampal (PHc) cortices. Streamline tractography generated edge weight (EW) metrics for the aforementioned ERc connections and, as comparison regions, connections between left and right rostral and caudal anterior cingulate cortex (ACC). Coefficients of variation (CoV) were derived for the surface area and volumes of these ERc connectivity-defined regions (CDR) and for EW across all ten scans, expecting that scan-to-scan reliability would yield low CoVs. TBSS revealed no significant variation in FA or MD across scanning sessions. Probabilistic tractography successfully reproduced histologically-verified adjacent medial temporal lobe circuits. Tractography-derived metrics displayed larger ranges of scanner-to-scanner variability. Connections involving HC displayed greater variability than metrics of connection between other investigated regions. By confirming the test retest reliability of HARDI data acquisition, support for the validity of significant results derived from diffusion data can be obtained.

Hydration status influences seed fire tolerance in temperate European herbaceous species

Prescribed burning is an important management tool in many parts of the world. While natural fires generally occur during the driest and warmest period of the year, prescribed burning is often timed out-of-season, when there is higher soil moisture and lower biomass combustibility. However, fire season may influence seedling recruitment after fire, e.g. through the effect of seed hydration status on fire tolerance. In non-fire-prone temperate regions, anthropogenic fire may occur exclusively in periods outside the growing season with higher soil moisture, which may have negative consequences on seedling recruitment. Fire tolerance of moist and dry seeds of 16 temperate European herbaceous species belonging to four families was assessed using heat treatment of 100 °C for 5 min and subsequent germination trials. Moist seeds of Asteraceae, Poaceae and Brassicaceae had a predominantly negative reaction to the heat treatment, while those of Fabaceae tolerated it or germination was even enhanced. The reaction of dry seeds was completely different, with positive responses in three species of the Fabaceae and fire tolerance in species of other families. Our results point out that hydration status may significantly influence the post-fire germination of seeds. Dry seeds were found to tolerate high heat, while moist seeds were harmed in more than half of the species. This implies that if prescribed burning is applied in temperate grasslands of Europe, it should be timed to dry periods of the dormant season in order to protect seeds from negative effects of fire.

Coulomb Mediated Hybridization of Excitons in Coupled Quantum Dots

We report Coulomb mediated hybridization of excitonic states in optically active InGaAs quantum dot molecules. By probing the optical response of an individual quantum dot molecule as a function of the static electric field applied along the molecular axis, we observe unexpected avoided level crossings that do not arise from the dominant single-particle tunnel coupling. We identify a new few-particle coupling mechanism stemming from Coulomb interactions between different neutral exciton states. Such Coulomb resonances hybridize the exciton wave function over four different electron and hole single-particle orbitals. Comparisons of experimental observations with microscopic eight-band k·p calculations taking into account a realistic quantum dot geometry show good agreement and reveal that the Coulomb resonances arise from broken symmetry in the artificial semiconductor molecule.

Evaluation of Therapy Management and Patient Compliance in Postmenopausal Patients with Hormone Receptor-positive Breast Cancer Receiving Letrozole Treatment: The EvaluateTM Study

Introduction: The EvaluateTM study (Evaluation of therapy management and patient compliance in postmenopausal hormone receptor-positive breast cancer patients receiving letrozole treatment) is a prospective, non-interventional study for the assessment of therapy management and compliance in the routine care of postmenopausal women with invasive hormone receptor-positive breast cancer receiving letrozole. The parameters for inclusion in the study are presented and discussed here. Material and Methods: Between January 2008 and December 2009 a total of 5045 patients in 310 study centers were recruited to the EvaluateTM study. Inclusion criteria were hormone receptor-positive breast cancer and adjuvant treatment or metastasis. 373 patients were excluded from the analysis for various reasons. Results: A total of 4420 patients receiving adjuvant treatment and 252 patients with metastasis receiving palliative treatment were included in the study. For 4181 patients receiving adjuvant treatment, treatment with the aromatase inhibitor letrozole commenced immediately after surgery (upfront). Two hundred patients had initially received tamoxifen and started aromatase inhibitor treatment with letrozole at 1-5 years after diagnosis (switch), und 39 patients only commenced letrozole treatment 5-10 years after diagnosis (extended endocrine therapy). Patient and tumor characteristics were within expected ranges, as were comorbidities and concurrent medication. Conclusion: The data from the EvaluateTM study will offer a good overview of therapy management in the routine care of postmenopausal women with hormone receptor-positive breast cancer. Planned analyses will look at therapy compliance and patient satisfaction with how information is conveyed and the contents of the conveyed information.

The role of phonons for exciton and biexciton generation in an optically driven quantum dot

For many applications of semiconductor quantum dots in quantum technology, well-controlled state preparation of the quantum dot states is mandatory. Since quantum dots are embedded in the semiconductor matrix, their interaction with phonons often plays a major role in the preparation process. In this review, we discuss the influence of phonons on three basically different optical excitation schemes that can be used for the preparation of exciton, biexciton and superposition states: a resonant excitation leading to Rabi rotations in the excitonic system, an excitation with chirped pulses exploiting the effect of adiabatic rapid passage and an off-resonant excitation giving rise to a phonon-assisted state preparation. We give an overview of experimental and theoretical results, showing the role of phonons and compare the performance of the schemes for state preparation.

Energy transport and coherence properties of acoustic phonons generated by optical excitation of a quantum dot

The energy transport of acoustic phonons generated by the optical excitation of a quantum dot as well as the coherence properties of these phonons are studied theoretically both for the case of a pulsed excitation and for a continuous wave (CW) excitation switched on instantaneously. For a pulsed excitation, depending on pulse area and pulse duration, a finite number of phonon wave packets is emitted, while for the case of a CW excitation a sequence of wave packets with decreasing amplitude is generated after the excitation has been switched on. We show that the energy flow associated with the generated phonons is partly related to coherent phonon oscillations and partly to incoherent phonon emission. The efficiency of the energy transfer to the phonons and the details of the energy flow depend strongly and in a non-monotonic way on the Rabi frequency exhibiting a resonance behavior. However, in the case of CW excitation it turns out that the total energy transferred to the phonons is directly linked in a monotonic way to the Rabi frequency.

Nanomagnonic devices based on the spin-transfer torque

Magnonics is based on signal transmission and processing by spin waves (or their quanta, called magnons) propagating in a magnetic medium. In the same way as nanoplasmonics makes use of metallic nanostructures to confine and guide optical-frequency plasmon-polaritons, nanomagnonics uses nanoscale magnetic waveguides to control the propagation of spin waves. Recent advances in the physics of nanomagnetism, such as the discovery of spin-transfer torque, have created possibilities for nanomagnonics. In particular, it was recently demonstrated that nanocontact spin-torque devices can radiate spin waves, serving as local nanoscale sources of signals for magnonic applications. However, the integration of spin-torque sources with nanoscale magnetic waveguides, which is necessary for the implementation of integrated spin-torque magnonic circuits, has not been achieved to date. Here, we suggest and experimentally demonstrate a new approach to this integration, utilizing dipolar field-induced magnonic nanowaveguides. The waveguides exhibit good spectral matching with spin-torque nano-oscillators and enable efficient directional transmission of spin waves. Our results provide a practical route for the implementation of integrated magnonic circuits utilizing spin transfer.

P1-12-21: Adjuvant Trastuzumab Treatment without Adjuvant Chemotherapy in Early Breast Cancer

Background: Trastuzumab (T) is approved in most Western countries for the treatment of early, HER2+ breast cancer (BC) parallel or sequential to adjuvant chemotherapy (CT). Nevertheless, as in metastatic disease, the antibody seems to be used without chemotherapy in a selected group of HER2+ patients (pt). The purpose of this analysis is to characterize this subgroup as well as describe safety and efficacy outcome parameters in this German prospective observation trial.

Methods: At present, 2870 patients (pts) have been enrolled and documented in this ongoing non-interventional study from 270 German centers. At data base closure for this analysis, sufficient documentation was available from 2422 eligible pts.

Results: The proportion of pts receiving T without preceding or concomitant CT (noCT) was 180/2422 (7.4%). This subgroup was characterized by higher age (median 58 vs.56 in the CT group, p=0.0026; ≥70 years: 18%/10%), smaller primaries (pT1 49%/43%, p=0.11), more favorable grading (G3 45%/53%, p=0.045), a higher proportion of positive hormone receptor (67%/61%, p=0.096) and less radiotherapy (64%/79%, p<0.0001). The strong association to radiotherapy is probably due to the fact, that the choice of this additional modality reflects the overall risk assessment of the pt.

In contrast, there was no difference in nodal involvement (pN0: 52%/51%; positive nodes: mean 2.5/2.4). In multivariate analysis (logistic regression model, not incorporating radiotherapy), hormone receptor status is not predictive (p=0.41), while age ≥65 (p=0.0011), grade 1/2 (p=0.046) and pT1 (p=0.089) independently remain at least borderline significant. The mean number of T administrations was 18 and the median duration of T therapy was 12 months in the noCT group as well as the CT group. 57% of the noCT pts received adjuvant endocrine therapy. In the CT group, 81% received anthracyclines and 61% taxanes.

Based on a still low number of only 13 observed events in the noCT group, no differences in relapse-free survival could be detected (p=0.38). Pathological cardiac findings in the pt's history was not predictive of therapy selection (6%/7%) and were also similarly distributed at the end of T therapy (7%/8%). Cardiac function disorders of CTC grade 3/4 were reported in 1% of both groups, across all grades slightly less frequent in the noCT group (2.8%/4.0%).

Conclusions: A small, but distinct group of early BC pts without adjuvant chemotherapy receives T treatment for HER2+ disease. These patients are characterized by higher age and favorable primary tumor staging and grading, but not by cardiac comorbidities.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-21.

Lattice fluctuations at a double phonon frequency with and without squeezing: an exactly solvable model of an optically excited quantum dot

Time-dependent lattice fluctuations of an optically excited strongly confined quantum dot are investigated with the aim to analyze the characteristics commonly used for identifying the presence of squeezed phonon states. It is demonstrated that the appearance of fluctuations oscillating with twice the phonon frequency, commonly regarded as a clear indication of squeezed states, cannot be considered as such. The source of the discrepancy with earlier investigations is discussed. Conditions for generating a squeezed state by using a two-pulse excitation are analyzed.

All-optical spin manipulation of a single manganese atom in a quantum dot

For a CdTe quantum dot doped with a single Mn atom we analyze the dynamics of the Mn spin when the dot is excited by ultrashort laser pulses. Because of the exchange interaction with the Mn atom, electron and hole spins can flip and induce a change of the Mn spin. Including both heavy and light-hole excitons and using suitable pulse sequences, angular momentum can be transferred from the light to the Mn system while the exciton system returns to its ground state. We show that by a series of ultrashort laser pulses the Mn spin can be selectively driven into each of its six possible orientations on a picosecond timescale. By applying a magnetic field the total switching time and the required number of pulses can be strongly reduced.

Detection of circulating tumor cells (CTCs) in patients with hepatocellular carcinoma (HCC)

15037

Background: Allard et al. (2004) has established the accuracy, sensitivity, reliability and linearity of circulating tumor cells (CTCs) detection using the CellSearch System. 57% prostate cancers, 37% breast cancers, 37% ovarian cancers, 30% colorectal cancers, and 20% lung cancers specimens had >= 2 CTCs per 7.5 mL of blood. Only 0.3% healthy non-malignant disease subjects had >= 2 CTCs per 7.5 mL of blood. Cristofanilli et al.(2004,2005) have shown that CTCs at baseline and first follow-up were a significant prognostic factor for survival in metastatic breast cancer patients. However, HCC data on CTCs are not available. Methods: 20 locally advance or metastatic HCC patients who had not received prior treatment had been recruited after informed consent and 7.5 mL of blood were collected using the CellSave Preservative tubes (Veridex LLC, Raritan, NJ) that prevents CTCs degradation. The CellSearch system (Veridex LLC) similar to the previous studies was used to analyze the specimen. The CellSearch system consists the CellPrep system, the CellSearch Epithelial Cell Kit, and the CellSpotter Analyzer. All the procedures and interpretation of results followed closely with the quality control procedure of Veridex LLC including accreditation of trained laboratory personnel. Results: 13/20 (65%) had locally advanced disease and the rest had metastatic HCC. All patients had multiple lesions. 9/20 (45%) patients had detectable CTCs, 7/20 (35%) had >= 2 CTCs, and about 5/20 (20%) had 5 or more CTCs. For locally advanced HCC 4/13 (31%) patients had >= 2 CTCs per 7.5 mL of blood. For HCC patients with metastatic diseases 3/7 (43%) patients had >= 2 CTCs per 7.5 mL of blood. Conclusions: HCC patients with locally advance or metastatic disease had detectable CTCs in 7.5 mL of blood. We expected that the performance of CTCs in HCC is similar to that of breast cancer. Future study of using CTCs as prognostic factor at baseline and during treatment for HCC is being planned.

No significant financial relationships to disclose.

Nonmonotonic field dependence of damping and reappearance of Rabi oscillations in quantum dots

The dynamics of strongly confined laser driven semiconductor quantum dots coupled to phonons is studied theoretically by calculating the time evolution of the reduced density matrix using a numerical path integral method. We explore the cases of long pulses, strong dot-phonon and dot-laser coupling, and high temperatures, which, up to now, have been inaccessible. We find that the phonon-induced damping of Rabi rotations is a nonmonotonic function of the laser field that is increasing at low fields and decreasing at high fields. This results in a reappearance of Rabi rotations at high fields. This phenomenon is of a general nature which occurs for all temperatures and carrier-phonon coupling strengths.

Influence of renal dysfunction on the pharmacokinetics of the selective Na+/H+ exchange inhibitor EMD 87 580 in patients with chronic heart failure

BACKGROUND

Chronic heart failure (CHF) is a potential indication for the administration of EMD 87 580, a selective Na+/H+ exchange inhibitor. CHF is often accompanied by renal dysfunction, which is known to affect the pharmacokinetics of compounds predominately cleared by the kidneys. We examined the influence of renal dysfunction on the pharmacokinetics of EMD 87 580 in patients with CHF.

METHODS

21 patients with CHF and normal renal function (Group 1) and 9 patients with CHF and renal dysfunction (Group 2) received EMD 87 580 orally over 8 days. The mean creatinine clearance (CrCl) in Group 1 was 99.7 ml/min. 12 patients in this group were randomized to receive two doses of EMD 87 580 (7 patients 2 x 50 mg and 5 patients 2 x 100 mg). The 9 patients in Group 2 with renal dysfunction (mean CrCl = 49.5 ml/min) received 50 mg EMD 87 580 once daily. Plasma and urine samples were collected for pharmacokinetic assessment.

RESULTS

In CHF patients with renal dysfunction EMD 87 580 clearance was reduced to approximately 50% compared to Group 1, i.e. 6.80 ml/min (4.89-11.60) vs. 12.73 ml/min (8.93-22.21), p < 0.05, for the 50 mg dose and 14.08 ml/min (9.96-18.10), p < 0.05, for the 100 mg dose. Consequently, plasma concentrations were increased in patients with renal dysfunction; AUC0-infinity 7,354 ng/ml x h (4,311-10,232) vs. 3,928 ng/ml x h (2,251-5,596, 50 mg dose, p < 0.05). A significant correlation was observed between EMD 87 580 plasma clearance and CrCl (r2 = 0.8062).

CONCLUSION

In CHF patients with renal dysfunction EMD 87 580, clearance is reduced and plasma concentrations increased. Therefore, dose adjustments for EMD 87 580 are indicated in patients with CHF and renal dysfunction.

Conserved patterns of protein interaction in multiple species

To elucidate cellular machinery on a global scale, we performed a multiple comparison of the recently available protein-protein interaction networks of Caenorhabditis elegans, Drosophila melanogaster, and Saccharomyces cerevisiae. This comparison integrated protein interaction and sequence information to reveal 71 network regions that were conserved across all three species and many exclusive to the metazoans. We used this conservation, and found statistically significant support for 4,645 previously undescribed protein functions and 2,609 previously undescribed protein interactions. We tested 60 interaction predictions for yeast by two-hybrid analysis, confirming approximately half of these. Significantly, many of the predicted functions and interactions would not have been identified from sequence similarity alone, demonstrating that network comparisons provide essential biological information beyond what is gleaned from the genome.

Estimating the memory time induced by exciton-exciton scattering

It is shown that lower bounds for the effective memory time induced by two-pair correlations can be estimated by monitoring changes of the shape of excitonic four-wave-mixing spectra. Experimentally we demonstrate a memory time of at least 540 fs for a ZnSe single quantum well. Microscopic calculations reveal that this lower bound is not sharp. Interactions retarded by more than 800 fs are shown to influence the dynamics, reflecting the presence of a long time tail in the memory kernel.

The development of an oral antidiabetic combination tablet: design, evaluation and clinical benefits for patients with type 2 diabetes

Type 2 diabetes is a chronic and progressive disease. Oral antidiabetic monotherapies directly address only one defect as their primary mechanism of action, and do not control blood glucose sufficiently well to meet current glycaemic targets. In consequence, most patients need combination therapy within a few years. However, the co-administration of two or more oral antidiabetic drugs may render treatment regimens difficult to follow. Combining oral antidiabetic agents into a single tablet provides a means of intensifying antidiabetic therapy while supporting good patient compliance. An insulin sensitiser and an insulin secretagogue represent a rational oral antidiabetic combination, as they address the dual endocrine defects of insulin resistance and impaired beta-cell function in type 2 diabetes. Nevertheless, the components of a combination tablet must be carefully chosen. Metformin (an insulin sensitiser) and glibenclamide (an insulin secretagogue) are well supported by decades of clinical evidence, and the pharmacokinetics of these agents support twice-daily co-administration. The final technical challenge is to optimise their delivery within a single-tablet combination. A recently-introduced metformin-glibenclamide combination tablet (Glucovance) has been extensively studied in well-designed clinical trials, where it has been shown to be more effective than its component monotherapies in controlling fasting and postprandial glycaemia. This treatment provides a case study in the development of a single-tablet oral antidiabetic combination, in terms of the pharmacokinetic issues facing the development of this preparation, and the implications of the pharmacokinetic properties of the components of the combination tablet on their pharmacodynamic actions and risk-benefit profile.

Intra-articular load distribution in the human ankle joint during motion

The rational treatment of injuries to the ankle is predicated on an understanding of biomechanics of the ankle. While several investigators have reported on three-dimensional dynamic kinematics of the ankle and on the static distribution of pressure within the ankle, it has not been possible to measure intra-articular forces reliably under dynamic conditions. The assumption that the distribution of forces under dynamic conditions is well represented by statically determined forces has not been validated, leaving in question the applicability to dynamic conditions of data obtained under static conditions. This study characterizes an electro-mechanical thin-membrane force transducer with potential for intra-articular use. The sensor was found to yield a reproducible linear response to loads experienced in the ankle, and was insensitive to both a moist environment and shearing forces. On the basis of these results, these force-transducers were placed in axially loaded cadaveric ankles that were either statically or dynamically cycled through a physiologic range of motion. In each of six specimens, sensors were secured to the medial and lateral malleolar articular surfaces, and to articular surfaces of the medial and lateral tibial plafond. Both medial and lateral malleolar-talar forces increased with dorsiflexion. Moving from plantarflexion to dorsiflexion caused an increase in lateral tibio-talar load accompanied by a decrease in the medial tibio-talar loading. There was no significant hysteresis in force-distribution with respect to the direction of sagittal motion. There was no difference between the forces measured under static or dynamic conditions. This study validates the use of static loading methodologies in future studies of force-distribution. Our data in intact ankles closely corresponded to data on forces under dynamic conditions. Dorsiflexion caused an increase in both medially and laterally directed forces towards the malleoli. This is the first demonstration of such forces, which are responsible for the external rotation and lateral translation of the distal fibula that occurs in dorsiflexion of the ankle.

2000 Wolfe Award. Sumatriptan for the range of headaches in migraine sufferers: results of the Spectrum Study

BACKGROUND

Migraineurs experience a spectrum of headaches: migraine, migrainous, and episodic tension-type as defined by the International Headache Society (IHS).

OBJECTIVE

To evaluate the effectiveness of sumatriptan, 50-mg tablets, in treating the spectrum of headaches in IHS-diagnosed migraineurs.

DESIGN/METHODS

Migraineurs with severe disability (Headache Impact Questionnaire score 250 or greater) were enrolled in a randomized, double-blind, placebo-controlled, crossover study. Patients treated up to 10 headaches with sumatriptan, 50 mg, or placebo (4:1). Headache features, recorded prior to treatment, were used to classify each headache using IHS criteria. Headache response (moderate or severe pain reduced to mild or no pain) and pain-free response were recorded at 2 and 4 hours postdose (primary endpoint). Because patients treated multiple attacks, statistical methods controlling for within-subject correlation were used.

RESULTS

Two hundred forty-nine migraineurs treated 1576 moderate or severe headaches: migraine (n = 1110), migrainous (n = 103), and tension-type (n = 363). Sumatriptan was superior to placebo for headache response 4 hours postdose (primary endpoint) across all headache types (migraine, 66% versus 48%; P<.001; migrainous, 71% versus 39%; P<.01; tension-type, 78% versus 50%, P<.001). Sumatriptan was also superior to placebo for pain-free response 4 hours postdose for migraine (41% versus 24%, P<.001) and tension-type headaches (56% versus 36%, P =.001). Sumatriptan provided superior pain-free response 2 hours postdose for migraine (18% versus 7%, P<.0001) and tension-type headache (28% versus 14%, P =.0005) compared with placebo.

CONCLUSION

Sumatriptan, 50-mg tablets, are effective for the full spectrum of headaches experienced by patients with disabling migraine due to a sumatriptan-responsive mechanism.