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1.
J Phys Condens Matter ; 36(8)2023 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-37931296

RESUMEN

Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy grown Ge1-xSnxfilms treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening - variable energy positron annihilation spectroscopy and variable energy positron annihilation lifetime spectroscopy are used to investigate the defect nanostructure in the Ge1-xSnxfilms exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, the positron annihilation spectroscopy analysis provides information about dislocations and Ge vacancies decorated by Sn atoms. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters.

2.
Sci Rep ; 13(1): 10164, 2023 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-37349374

RESUMEN

To evaluate the influence of the blood-brain barrier on neuronal gadolinium deposition in a mouse model after multiple intravenous applications of the linear contrast agent gadodiamide. The prospective study held 54 mice divided into three groups: healthy mice (A), mice with iatrogenic induced disturbance of the blood-brain barrier by glioblastoma (B) or cerebral infarction (C). In each group 9 animals received 10 iv-injections of gadodiamide (1.2 mmol/kg) every 48 h followed by plain T1-weighted brain MRI. A final MRI was performed 5 days after the last contrast injection. Remaining mice underwent MRI in the same time intervals without contrast application (control group). Signal intensities of thalamus, pallidum, pons, dentate nucleus, and globus pallidus-to-thalamus and dentate nucleus-to-pons ratios, were determined. Gadodiamide complex and total gadolinium amount were quantified after the last MR examination via LC-MS/MS and ICP-MS. Dentate nucleus-to-pons and globus pallidus-to-thalamus SI ratios showed no significant increase over time within all mice groups receiving gadodiamide, as well as compared to the control groups at last MR examination. Comparing healthy mice with group B and C after repetitive contrast administration, a significant SI increase could only be detected for glioblastoma mice in globus pallidus-to-thalamus ratio (p = 0.033), infarction mice showed no significant SI alteration. Tissue analysis revealed significantly higher gadolinium levels in glioblastoma group compared to healthy (p = 0.013) and infarction mice (p = 0.029). Multiple application of the linear contrast agent gadodiamide leads to cerebral gadolinium deposition without imaging correlate in MRI.


Asunto(s)
Glioblastoma , Compuestos Organometálicos , Ratones , Animales , Medios de Contraste/farmacología , Barrera Hematoencefálica/diagnóstico por imagen , Gadolinio/farmacología , Cromatografía Liquida , Estudios Prospectivos , Estudios Retrospectivos , Espectrometría de Masas en Tándem , Gadolinio DTPA , Imagen por Resonancia Magnética/métodos , Globo Pálido , Modelos Animales de Enfermedad
3.
J Phys Condens Matter ; 35(5)2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36395508

RESUMEN

The pseudomorphic growth of Ge1-xSnxon Ge causes in-plane compressive strain, which degrades the superior properties of the Ge1-xSnxalloys. Therefore, efficient strain engineering is required. In this article, we present strain and band-gap engineering in Ge1-xSnxalloys grown on Ge a virtual substrate using post-growth nanosecond pulsed laser melting (PLM). Micro-Raman and x-ray diffraction (XRD) show that the initial in-plane compressive strain is removed. Moreover, for PLM energy densities higher than 0.5 J cm-2, the Ge0.89Sn0.11layer becomes tensile strained. Simultaneously, as revealed by Rutherford Backscattering spectrometry, cross-sectional transmission electron microscopy investigations and XRD the crystalline quality and Sn-distribution in PLM-treated Ge0.89Sn0.11layers are only slightly affected. Additionally, the change of the band structure after PLM is confirmed by low-temperature photoreflectance measurements. The presented results prove that post-growth ns-range PLM is an effective way for band-gap and strain engineering in highly-mismatched alloys.

5.
Lipids Health Dis ; 19(1): 167, 2020 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-32660564

RESUMEN

BACKGROUND: Many patients suffering from exercise-induced asthma (EIA) have normal lung function at rest and show symptoms and a decline in FEV1 when they do sports or during exercise-challenge. It has been described that long-chain polyunsaturated fatty acids (LCPUFA) could exert a protective effect on EIA. METHODS: In this study the protective effect of supplementation with a special combination of n-3 and n-6 LCPUFA (sc-LCPUFA) (total 1.19 g/ day) were investigated in an EIA cold air provocation model. PRIMARY OUTCOME MEASURE: Decrease in FEV1 after exercise challenge and secondary outcome measure: anti-inflammatory effects monitored by exhaled NO (eNO) before and after sc-LCPUFA supplementation versus placebo. RESULTS: Ninety-nine patients with exercise-induced symptoms aged 10 to 45 were screened by a standardized exercise challenge in a cold air chamber at 4 °C. Seventy-three patients fulfilled the inclusion criteria of a FEV1 decrease > 15% and were treated double-blind placebo-controlled for 4 weeks either with sc-LCPUFA or placebo. Thirty-two patients in each group completed the study. Mean FEV1 decrease after cold air exercise challenge and eNO were unchanged after 4 weeks sc-LCPUFA supplementation. CONCLUSION: Supplementation with sc-LCPUFA at a dose of 1.19 g/d did not have any broncho-protective and anti-inflammatory effects on EIA. TRIAL REGISTRATION: Clinical trial registration number: NCT02410096. Registered 7 February 2015 at Clinicaltrial.gov.


Asunto(s)
Asma Inducida por Ejercicio/prevención & control , Ácidos Grasos Omega-3/uso terapéutico , Ácidos Grasos Omega-6/uso terapéutico , Adolescente , Adulto , Cromatografía de Gases , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Óxido Nítrico/análisis , Adulto Joven
6.
Orthopade ; 49(6): 510-521, 2020 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-31720704

RESUMEN

BACKGROUND: Knee pain can influence postural control in addition to changes in the anatomical structure of the knee joints. OBJECTIVE: Because the influence of imbalances in the craniomandibular system has been proven multiple times, it is the aim of the present work to investigate the influence of various knee diagnoses on postural control excluding occlusal information by means of symmetrical packing using cotton rolls. MATERIALS AND METHODS: One hundred and fifteen patients (74 male/41 female) aged 18-75 years with an average BMI of 25.13 ± 3.66 kg/m2 took part in the study, among them 34 patients (26 male/8 female) with cruciate ligament injury, 26 (16 male/10 female) with meniscal lesions, 24 (13 male/11 female) with arthrosis, 21 (11 male/10 female) with patellar pain, and 10 (8 male/2 female) with other painful knee complaints. Postural control was increased using a force platform, the degree of severity of the disorder was recorded using the "Knee Injury and Osteoarthritis Outcome" questionnaire, and the occlusion packed on both sides with cotton rolls in the premolar area. RESULTS: With increasing age, patients with knee arthrosis are more likely to stand on the hindfoot. In those with patellar disorder, increased weight-bearing on the forefoot correlates with increasing BMI. An increase in weight-bearing on the forefoot on the side of the uninjured knee in people with patellar disorder results not only in a reduction in quality of life but also level of daily activity. DISCUSSION: The percentage weight-bearing on the zones of the feet differs in unilateral knee injuries (in particular, comparison of the side with the knee injury and the uninjured side). Age, BMI or gender are influencing factors. Because various correlations and/or effects in the subgroups of knee injuries are generated, an injury-specific analysis should be carried out. These effects are also identifiable in the subjective assessment of quality of life.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior/cirugía , Ligamento Cruzado Anterior/cirugía , Procedimientos Ortopédicos/métodos , Osteoartritis de la Rodilla/complicaciones , Equilibrio Postural , Soporte de Peso , Adolescente , Adulto , Anciano , Ligamento Cruzado Anterior/diagnóstico por imagen , Lesiones del Ligamento Cruzado Anterior/diagnóstico por imagen , Femenino , Humanos , Traumatismos de la Rodilla , Articulación de la Rodilla , Masculino , Persona de Mediana Edad , Dolor , Calidad de Vida , Adulto Joven
8.
Med Klin Intensivmed Notfmed ; 115(2): 140-147, 2020 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-30721334

RESUMEN

BACKGROUND: Intensive care unit (ICU) treatment may be associated with mental symptoms such as anxiety, depressed mood, hopelessness and nightmares in critically ill patients. While many physical symptoms can be detected via standardized measures, an instrument to assess mental symptoms is actually missing. OBJECTIVES: An existing validated screening tool to detect mental symptoms in critically ill patients, the Intensive Care Psychological Assessment Tool (IPAT), has been translated into German and tested in two surgical ICUs and an intermediate care unit. MATERIALS AND METHODS: In addition to the German translation of the IPAT, Stait-Trait-Anxiety-Inventory (STAI-SKD) and Hospital Anxiety and Depression Scale (HADS-D) were used to determine convergent validity. Within a survey period of 3 months, a total of 90 awake and fully oriented patients were included in the study. RESULTS: Internal consistency of the German translation was lower than that of the original study. The initial factor structure was partially replicated. Convergent validity was demonstrated for depressive and anxiety symptoms, but not for the presence of delirium. Patients who completed the screening were frequently suffering from sleep disturbances, tension, anxiety and depressed mood. A total of 37% of the patients exceeded the cut-off and are considered at-risk patients for psychological sequelae. DISCUSSION: With regard to test quality, the results of the German version are currently not satisfactory. This may be due to the small sample size and sample selectivity, which is also the largest limitation of the study. The instrument proved to be practicable if patients can complete it as an interview. The adaptation for external assessment seems to be useful to capture psychological stress in patients with impaired communication and perception.


Asunto(s)
Cuidados Críticos , Trastornos Mentales , Ansiedad , Enfermedad Crítica , Humanos , Unidades de Cuidados Intensivos , Encuestas y Cuestionarios
9.
Transl Med UniSa ; 23: 1-5, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34447703

RESUMEN

To develop trainings on the implementation of smart healthy age-friendly environments for people who aim to support, for example, their parents, their neighbours or local community, there are precautionary measures that have to be taken into account: the role of the facilitator (volunteer or self-employed), the level of skills, the needs of the end-users, training content and methodologies together with the sustainability of the learning. This article examines these aspects, based on desk research and expert interviews in the Smart Healthy Age-Friendly Environments (SHAFE) fields.

10.
HNO ; 67(Suppl 2): 69-76, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31065762

RESUMEN

BACKGROUND: In the field of hearing research a variety of imaging techniques are available to study molecular and cellular structures of the cochlea. Most of them are based on decalcifying, embedding, and cutting of the cochlea. By means of scanning laser optical tomography (SLOT), the complete cochlea can be visualized without cutting. The Cav1.3-/- mice have already been extensively characterized and show structural changes in the inner ear. Therefore, they were used in this study as a model to investigate whether SLOT can detect structural differences in the murine cochlea. MATERIALS AND METHODS: Whole undissected cochleae from Cav1.3-/- and wild-type mice of various postnatal stages were immunostained and analyzed by SLOT. The results were compared to cochlea preparations that were immunostained and analyzed by fluorescence microscopy. In addition, cochlea preparations were stained with osmium tetraoxide. RESULTS: Visualization by SLOT showed that the staining of nerve fibers at P27 in Cav1.3-/- mice was almost absent compared to wild-type mice and earlier timepoints (P9). The analysis of cochlea preparations confirmed a reduction of the radial nerve fibers. In addition, a significantly reduced number of ribbon synapses per inner hair cell (IHC) at P20 and P27 in the apical part of the cochlea of Cav1.3-/- mice was detected. CONCLUSION: The visualization of whole non-dissected cochleae by SLOT is a suitable tool for the analysis of gross phenotypic changes, as demonstrated by means of the Cav1.3-/- mouse model. For the analysis of finer structures of the cochlea, however, further methods must be used.


Asunto(s)
Cóclea , Células Ciliadas Auditivas Internas/ultraestructura , Tomografía Óptica , Animales , Modelos Animales de Enfermedad , Ratones , Sinapsis , Tomografía Óptica/métodos
11.
HNO ; 67(8): 590-599, 2019 Aug.
Artículo en Alemán | MEDLINE | ID: mdl-30963223

RESUMEN

BACKGROUND: In the field of hearing research a variety of imaging techniques are available to study molecular and cellular structures of the cochlea. Most of them are based on decalcifying, embedding, and cutting of the cochlea. By means of scanning laser optical tomography (SLOT), the complete cochlea can be visualized without cutting. The Cav1.3-/- mice have already been extensively characterized and show structural changes in the inner ear. Therefore, they were used in this study as a model to investigate whether SLOT can detect structural differences in the murine cochlea. MATERIALS AND METHODS: Whole undissected cochleae from Cav1.3-/- and wildtype mice of various postnatal stages were immunostained and analyzed by SLOT. The results were compared to cochlea preparations that were immunostained and analyzed by fluorescence microscopy. In addition, cochlea preparations were stained with osmium tetraoxide. RESULTS: Visualization by SLOT showed that the staining of nerve fibers at P27 in Cav1.3-/- mice was almost absent compared to wildtype mice and earlier timepoints (P9). The analysis of cochlea preparations confirmed a reduction of the radial nerve fibers. In addition, a significantly reduced number of ribbon synapses per inner hair cell (IHC) at P20 and P27 in the apical part of the cochlea of Cav1.3-/- mice was detected. CONCLUSION: The visualization of whole non-dissected cochleae by SLOT is a suitable tool for the analysis of gross phenotypic changes, as demonstrated by means of the Cav1.3-/- mouse model. For the analysis of finer structures of the cochlea, however, further methods must be used.


Asunto(s)
Células Ciliadas Auditivas Internas , Tomografía Óptica , Animales , Cóclea , Modelos Animales de Enfermedad , Células Ciliadas Auditivas Internas/ultraestructura , Ratones , Sinapsis , Tomografía Óptica/métodos
12.
Drug Test Anal ; 10(4): 723-730, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28901724

RESUMEN

Today's doping tests involve longitudinal monitoring of urinary steroids including the testosterone glucuronide and epitestosterone glucuronide ratio (T/E) in an Athlete Biological Passport (ABP). The aim of this study was to investigate the possible influence of short-term use of codeine on the urinary excretion of androgen metabolites included in the steroidal module of the passport prior to and after the co-administration with testosterone. The study was designed as an open study with the subjects being their own control. Fifteen healthy male volunteers received therapeutic doses of codeine (Kodein Meda) for 6 days. On Day 3, 500 mg or 125 mg of testosterone enanthate (Testoviron®-Depot) was administered. Spot urine samples were collected for 17 days, and blood samples were collected at baseline, 3, 6, and 14 days after codeine intake. The circulatory concentration of total testosterone decreased significantly by 20% after 3 days' use of codeine (p = 0.0002) and an atypical ABP result was noted in one of the subjects. On the other hand, the concomitant use of codeine and testosterone did not affect the elevated urinary T/E ratio. In 75% of the individuals, the concentration of urinary morphine (a metabolite of codeine) was above the decision limit for morphine. One of the participants displayed a morphine/codeine ratio of 1.7 after codeine treatment, indicative of morphine abuse. In conclusion, our study shows that codeine interferes with the endogenous testosterone concentration. As a result, the urinary steroid profile may lead to atypical findings in the doping test.


Asunto(s)
Andrógenos/sangre , Andrógenos/orina , Codeína/sangre , Codeína/orina , Detección de Abuso de Sustancias/métodos , Testosterona/sangre , Testosterona/orina , Adolescente , Adulto , Cromatografía Líquida de Alta Presión/métodos , Doping en los Deportes , Humanos , Límite de Detección , Masculino , Persona de Mediana Edad , Morfina/orina , Espectrometría de Masas en Tándem/métodos , Testosterona/análogos & derivados , Adulto Joven
13.
Allergy ; 72(12): 1912-1915, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28581121

RESUMEN

BACKGROUND: Omalizumab is licensed for therapy in severe allergic asthma with an effect demonstrated after 8 weeks or longer treatment. As new applications for omalizumab demand precise knowledge of the onset of effects, the objective of this study was to determine the time course of the early (EAR) and late allergic reaction (LAR). MATERIALS AND METHODS: Ten patients (IgE>300 IU/mL and <700 IU/mL) with a significant response to allergen challenge were treated with omalizumab according to the approved dosing table. Bronchial allergen provocations (BAP) were repeated at weeks 1, 2, 4, and 8. RESULTS: EAR was significantly reduced after 4 weeks (ΔFEV1 28% vs 11%; P<.001), eNO (86 vs 53 ppb; P<.05) and basophil activation after 2 weeks (CD63 expression 79% vs 32%, P<.05) and LAR already after 1 week (ΔFEV1 26% vs 13%, P<.05). CONCLUSION: These results demonstrate the onset of protective effects earlier than previously determined, potentially improving seasonal utilization and combination with immunotherapy.


Asunto(s)
Antiasmáticos/uso terapéutico , Asma/tratamiento farmacológico , Asma/inmunología , Hipersensibilidad/inmunología , Hipersensibilidad/prevención & control , Omalizumab/uso terapéutico , Adulto , Alérgenos/inmunología , Antiasmáticos/farmacología , Asma/diagnóstico , Basófilos/inmunología , Basófilos/metabolismo , Biomarcadores , Femenino , Humanos , Masculino , Óxido Nítrico/metabolismo , Omalizumab/farmacología , Factores de Tiempo , Resultado del Tratamiento , Adulto Joven
14.
Nat Commun ; 8: 14870, 2017 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-28367950

RESUMEN

A non-classical light source emitting pairs of identical photons represents a versatile resource of interdisciplinary importance with applications in quantum optics and quantum biology. To date, photon twins have mostly been generated using parametric downconversion sources, relying on Poissonian number distributions, or atoms, exhibiting low emission rates. Here we propose and experimentally demonstrate the efficient, triggered generation of photon twins using the energy-degenerate biexciton-exciton radiative cascade of a single semiconductor quantum dot. Deterministically integrated within a microlens, this nanostructure emits highly correlated photon pairs, degenerate in energy and polarization, at a rate of up to (234±4) kHz. Furthermore, we verify a significant degree of photon indistinguishability and directly observe twin-photon emission by employing photon-number-resolving detectors, which enables the reconstruction of the emitted photon number distribution. Our work represents an important step towards the realization of efficient sources of twin-photon states on a fully scalable technology platform.

15.
Osteoporos Int ; 28(7): 2081-2093, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28365851

RESUMEN

Our results suggest that the prevalence of bone health deficits in children with CP was overestimated, when using only age- and height-adjusted bone mineral content (BMC) and areal bone mineral density (aBMD). When applying the functional muscle-bone unit diagnostic algorithm (FMBU-A), the prevalence of positive results decreased significantly. We recommend applying the FMBU-A when assessing bone health in children with CP. INTRODUCTION: The prevalence of bone health deficits in children with cerebral palsy (CP) might be overestimated because age- and height-adjusted reference percentiles for bone mineral content (BMC) and areal bone mineral density (aBMD) assessed by dual-energy X-ray absorptiometry (DXA) do not consider reduced muscle activity. The aim of this study was to compare the prevalence of positive DXA-based indicators for bone health deficits in children with CP to the prevalence of positive findings after applying a functional muscle-bone unit diagnostic algorithm (FMBU-A) considering reduced muscle activity. METHODS: The present study was a monocentric retrospective analysis of 297 whole body DXA scans of children with CP. The prevalence of positive results of age- and height-adjusted BMC and aBMD defined as BMC and aBMD below the P3 percentile and of the FMBU-A was calculated. RESULTS: In children with CP, the prevalence of positive results of age-adjusted BMC were 33.3% and of aBMD 50.8%. Height-adjusted results for BMC and aBMD were positive in 16.8 and 36.0% of cases. The prevalence of positive results applying the FMBU-A regarding BMC and aBMD were significantly (p < 0.001) lower than using age- and height-adjusted BMC and aBMD (8.8 and 14.8%). CONCLUSIONS: Our results suggest that the prevalence of bone health deficits in children with CP was overestimated, when using age- and height-adjusted BMC and aBMD. When applying the FMBU-A, the prevalence decreased significantly. We recommend applying the FMBU-A when assessing bone health in children with CP.


Asunto(s)
Densidad Ósea/fisiología , Parálisis Cerebral/fisiopatología , Músculo Esquelético/fisiopatología , Absorciometría de Fotón/métodos , Adolescente , Parálisis Cerebral/complicaciones , Niño , Femenino , Humanos , Masculino , Osteoporosis/etiología , Osteoporosis/fisiopatología , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Factores Sexuales , Adulto Joven
16.
Clin Microbiol Infect ; 23(2): 119.e1-119.e7, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27756710

RESUMEN

OBJECTIVES: Aim of this study was to detect microorganisms in fetal membranes and placental tissue in preterm chorioamnionitis by combining fluorescence in situ hybridization (FISH) with broad range PCR. The combination of the two molecular techniques enables identification and localization of the microorganisms within the tissue, confirming their clinical relevance. METHODS: In a prospective cohort study, we compared 31 women with preterm premature rupture of membranes or preterm labour and preterm delivery by caesarean section with a control group of 26 women undergoing elective caesarean section at term. Fetal membranes and placental tissue were analysed by FISH and broad range 16S rRNA-gene PCR and sequencing. RESULTS: For 20 women in the preterm group, caesarean section was performed because of a clinical diagnosis of chorioamnionitis. Microorganisms were detected in the tissues by both molecular techniques in 11 out of 20 women. Among those, Ureaplasma spp. was most abundant, with five cases that remained culture-negative and would have been missed by routine diagnostic procedures. Other infections were caused by Staphylococcus aureus, Streptococcus mitis or Escherichia coli. FISH and PCR were negative for all women without suspected chorioamnionitis and for the control group. CONCLUSIONS: Combination of FISH with broad-range PCR and sequencing permitted unambiguous identification of the causative microorganisms in chorioamnionitis. The high prevalence of Ureaplasma spp. should lead to a re-evaluation of its clinical significance and possible therapeutic consequences.


Asunto(s)
Corioamnionitis/diagnóstico , Corioamnionitis/microbiología , Complicaciones Infecciosas del Embarazo , Nacimiento Prematuro , Infecciones por Ureaplasma/diagnóstico , Infecciones por Ureaplasma/microbiología , Ureaplasma , Adolescente , Adulto , Femenino , Humanos , Hibridación Fluorescente in Situ , Persona de Mediana Edad , Placenta/microbiología , Embarazo , Estudios Prospectivos , ARN Ribosómico 16S , Factores de Riesgo , Ureaplasma/clasificación , Ureaplasma/genética , Adulto Joven
17.
Opt Lett ; 41(18): 4398-400, 2016 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-27628407

RESUMEN

GeSn as a group-IV material opens up new possibilities for realizing photonic device concepts in Si-compatible fabrication processes. Here we present results of the ellipsometric characterization of highly p- and n-type doped Ge0.95Sn0.05 alloys deposited on Si substrates investigated in the wavelength range from 1 to 16 µm. We discuss the suitability of these films for integrated plasmonic applications in the infrared region.

18.
Phys Rev Lett ; 116(3): 033601, 2016 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-26849594

RESUMEN

We probe the indistinguishability of photons emitted by a semiconductor quantum dot (QD) via time- and temperature-dependent two-photon interference (TPI) experiments. An increase in temporal separation between consecutive photon emission events reveals a decrease in TPI visibility on a nanosecond time scale, theoretically described by a non-Markovian noise process in agreement with fluctuating charge traps in the QD's vicinity. Phonon-induced pure dephasing results in a decrease in TPI visibility from (96±4)% at 10 K to a vanishing visibility at 40 K. In contrast to Michelson-type measurements, our experiments provide direct access to the time-dependent coherence of a quantum emitter on a nanosecond time scale.

19.
Eur Arch Otorhinolaryngol ; 273(3): 649-54, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25753257

RESUMEN

The relative frequency of regional lymphogenic versus distant hematogenic metastases was evaluated in 369 patients with sinonasal adenocarcinoma of the intestinal type (ITAC). We assessed the results of neck dissections for a limited number of patients undergoing this surgical intervention. 117 ITAC patients were followed up for at least 5 years. Neck dissections were performed in 18 cases (15 primary and 3 secondary operations), 4 of which revealed carcinoma-positive lymph nodes. Metastases in lymph nodes were also diagnosed clinically in three other patients adding up to a total of seven individuals (6 % of 117) with lymphogenic metastases. In comparison, distant hematogenic metastases were identified in 15.4 % of these 117 patients. In the second group of 252 patients, the occurrence of distant hematogenic metastases and colorectal adenocarcinomas was registered but no formal follow-up procedure was applied. 50 neck dissections were performed in this group, 46 of which exhibited no histological evidence for metastases in lymph nodes, while in 1 case they were carcinoma-positive. Three additional cases showed clinical signs of metastases in regional lymph nodes. Taken together, our observations indicate that regional lymphogenic metastases are rather rare (about 2 %) in patients with sinonasal adenocarcinoma of the intestinal type. Therefore, the surgery of neck dissection appears not advised as routine intervention in these cases. ITAC patients show a normal prevalence of colorectal adenocarcinomas.


Asunto(s)
Adenocarcinoma , Ganglios Linfáticos/patología , Metástasis de la Neoplasia , Neoplasias Nasales , Neoplasias de los Senos Paranasales , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Anciano , Neoplasias Colorrectales/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Disección del Cuello/métodos , Metástasis de la Neoplasia/fisiopatología , Neoplasias Nasales/patología , Neoplasias Nasales/cirugía , Neoplasias de los Senos Paranasales/patología , Neoplasias de los Senos Paranasales/cirugía
20.
Nat Commun ; 6: 7662, 2015 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-26179766

RESUMEN

The success of advanced quantum communication relies crucially on non-classical light sources emitting single indistinguishable photons at high flux rates and purity. We report on deterministically fabricated microlenses with single quantum dots inside which fulfil these requirements in a flexible and robust quantum device approach. In our concept we combine cathodoluminescence spectroscopy with advanced in situ three-dimensional electron-beam lithography at cryogenic temperatures to pattern monolithic microlenses precisely aligned to pre-selected single quantum dots above a distributed Bragg reflector. We demonstrate that the resulting deterministic quantum-dot microlenses enhance the photon-extraction efficiency to (23±3)%. Furthermore we prove that such microlenses assure close to pure emission of triggered single photons with a high degree of photon indistinguishability up to (80±7)% at saturation. As a unique feature, both single-photon purity and photon indistinguishability are preserved at high excitation power and pulsed excitation, even above saturation of the quantum emitter.

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