Density and size control of InP/GaInP quantum dots on GaAs substrate grown by gas source molecular beam epitaxy.

We demonstrate a method to controllably reduce the density of self-assembled InP quantum dots (QDs) by cyclic deposition with growth interruptions. Varying the number of cycles enabled a reduction of the QD density from 7.4 × 10(10) cm(-2) to 1.8 × 10(9) cm(-2) for the same total amount of deposited InP. Simultaneously, a systematic increase of the QD size could be observed. Emission characteristics of different-sized InP QDs were analyzed. Excitation power dependent and time-resolved measurements confirm a transition from type I to type II band alignment for large InP quantum dots. Photon autocorrelation measurements of type I QDs performed under pulsed excitation reveal pronounced antibunching (g((2))(τ = 0) = 0.06 ± 0.03) as expected for a single-photon emitter. The described growth routine has great promise for the exploitation of InP QDs as quantum emitters.

[Radiotherapy : an option for refractory salivary fistulas]. / Radiatio : Therapieoption bei therapierefraktärer Speichelfistel.

A 45-year-old patient presented with refractory salivary fistula, attributed to multiple surgery and Botulinum toxin, following lateral parotidectomy. He underwent fractionated radiotherapy of the remaining parotid gland including the fistula opening (total dose of 30 Gy) at our clinic. In time, fistula secretion could be inhibited completely. Although the indication for radiotherapy for such fistulas is rare since Botulinum toxin has been in use, it should still be considered in refractory disease courses.

Influence of PET/CT-introduction on PET scanning frequency and indications. Results of a multicenter study.

AIM: To evaluate the influence of the introduction of combined PET/CT scanners into clinical routine. This investigation addresses the quantitative changes between PET/CT and stand alone PET. METHODS: The study included all examinations performed on stand alone PET- or PET/CT-scanners within 12 month prior to and after implementation of PET/CT. The final data analysis included five university hospitals and a total number of 15 497 exams. We distinguished exams on stand alone tomographs prior to and after installation of the combined device as well as PET/CT scans particularly with regard to disease entities. Various further parameters were investigated. RESULTS: The overall number of PET scans (PET and PET/CT) rose by 146% while the number of scans performed on stand alone scanners declined by 22%. Only one site registered an increase in stand alone PET. The number of exams for staging in oncology increased by 196% while that of cardiac scans decreased by 35% and the number of scans in neurology rose by 47%. The use of scans for radiotherapy planning increased to 7% of all PET/CT studies. The increase of procedures for so-called classic PET oncology indications was moderate compared to the more common tumors. An even greater increase was observed in some rare entities. CONCLUSIONS: The introduction of PET/CT led to more than a doubling of overall PET procedures with a main focus on oncology. Some of the observed changes in scanning frequency may be caused by a rising availability of new radiotracers and advancements of competing imaging methods. Nevertheless the evident increase in the use of PET/CT for the most common tumour types demonstrates its expanding role in cancer staging. The combination of molecular and morphologic imaging has not only found its place but is still gaining greater importance with new developments in technology and radiochemistry.

The Triply Twisted Heart: Cyanosis in an Adult With Situs Inversus, Levocardia, Double Outlet Right Ventricle, and Malposition of the Great Arteries.

We present a case of a 19-year-old female presenting with cyanosis since birth. The major anomaly demonstrated was a "triply twisted heart" with a balanced physiology, allowing her to survive into adulthood. Non-invasive imaging was done using 2D and real-time 3D (or 4D) echocardiography with multi-slice imaging from 4D volume datasets. Findings were confirmed using cardiac magnetic resonance imaging (MRI). A segmental approach revealed atrial and visceral situs inversus, levocardia, atrioventricular discordance, and ventriculoarterial discordance. Both the aorta and pulmonary artery were malposed and arise from the right ventricle (double outlet right ventricle or DORV). There was also a complete atrioventricular septal defect (CAVSD) associated with a functional single atrium and a functional univentricle (single ventricle). Other findings include a severe pulmonic stenosis (PS), preserved right and left ventricular systolic function, and a normal pulmonary arterial pressure. She also had a persistent left superior vena cava (SVC) that drains into the morphologic right atrium, while the right-sided SVC drains into the morphologic left atrium. A multidisciplinary team deemed that management be palliative. She is on regular follow-up at our clinics for non-invasive monitoring. To our knowledge, this is the first reported case in an adult with this combination of anomalies.

Long term changes in serum T4, T3, and TSH in benign thyroid disease: proof of a narrow individual variation.

AIM: The diagnosis of abnormalities of thyroid function is generally based on the measurement of thyroid hormones and TSH in blood. The recommended reference ranges for serum T4 and T3 as well as TSH are quite wide as the result of large differences in thyroid function tests in healthy persons. It has been proven that the individual variation within an individual is small, compared with the variation between individuals. We investigated long term variations of these parameters in patients with and without benign thyroid diseases. METHODS: We performed long term follow-up serum determinations of T3, T4, and TSH in a total of 150 patients for a time period of 3 to 13 years. The majority of patients had been put on L-thyroxine. Values of total T3, total T4, free T4 were measured with an almost unmodified test (RIA) over the years. RESULTS: The lowest relative coefficient of variation (<10%) was observed in the group of patients who had been treated with L-thyroxine only. Even for TSH, relatively low cofficients of variation were observed in this group. In the group of patients who had not received any medication, T3 and T4 showed also a variation of 10%. FT4 and TSH revealed a wider range of variation. Even after radioiodine therapy, T3 and T4 showed only a quite small variation, while TSH demonstrated a wide range with a variation of >30%. CONCLUSION: Our data demonstrate that there are only narrow variations of serum T4 and T3 within individuals with and without thyroid disorders.

[Effectiveness of syringe shieldings using radionuclides in radiation synovectomy]. / Effizienz von Spritzenabschirmungen bei Radionuklidanwendung zur Radiosynoviorthese.

AIM: The radiation exposure in radiation synovectomy was investigated for technician and therapist using Erbium-169, Rhenium-186 and Yttrium-90 with and without syringe shieldings. METHODS: Dose rates were measured in relation to the distance of the syringe containing the radionuclide. Measurements were repeated using syringe shieldings which consist of plastic surrounded by a lead layer. RESULTS: The most relevant radiation exposure arises from Yttrium-90. Using syringe shieldings radiation exposure can be reduced by a factor of thousand. CONCLUSION: This kind of radiological protection is completely sufficient for the therapist. Concerning the technician preparing the radiopharmaceutics, the limit of the official German dosimetry service (500 mSv) might be exceeded if no special radiological protection is established. Thus, special dosimetry is recommended.

Peripheral scotoma associated with chronic ethmoidal sinusitis. A case report and review of the literature.

Diseases of the paranasal sinuses may cause visual disturbances, especially diminished visual acuity and visual field defects, by affecting the optic nerve. We report the unusual case of a female patient with unilateral peripheral, quadrantic scotoma and concomitant chronic ethmoidal sinusitis. Visual acuity was not diminished. Despite extensive diagnostic examinations no other cause of the scotoma could be evaluated. As conservative therapy had been unsuccessful, endonasal pansinus operation was performed. Upon surgery, nearly all ethmoidal cells appeared to be filled with polypous mucosa. The sphenoid sinuses, however, contained air. In contrast, pre-operative CT scans had shown only a slight opacity of the ethmoid bone. Already two weeks after surgery a reduction in size of the scotoma could be noted. In addition to this case report, possible causes of visual field defects due to inflammatory diseases of the paranasal sinuses are discussed. In cases of unilateral visual field reduction associated with symptoms of chronic paranasal sinusitis, early operative exploration of the paranasal sinuses should be considered after exclusion of other possible causes, even if radiological findings do not warrant such a procedure.

[Proof of natural spontaneous activity of pelvic and anal musculature by combined positron emission therapy and computed tomography. Importance for diagnosis and therapy]. / Nachweis der natürlichen Spontanaktivität der Beckenboden- und Analmuskulatur durch das PET-CT. Bedeutung für die Diagnostik und Therapie.

Since 1991 we have known that the entire abdominal musculature has a distinct resting tone. All other muscles lose their tension almost completely during the resting phase. Only the craniopharyngeal and anorectal sphincter systems retain natural spontaneous activity, which ceases only when a hollow organ is opened. This permanent natural spontaneous activity is extremely sensitive. For example, it increases during coughing and speech. With combined positron emission and computed tomography, it is possible to observe and measure this natural spontaneous activity in the adjacent musculature very clearly. This fact is important for understanding and therapy of the function and failure of sphincter systems.

Lymph node positive head and neck carcinoma after curative radiochemotherapy: a long lasting debate on elective post-therapeutic neck dissections comes to a conclusion.

There has been a long lasting debate, whether planned neck dissections after curative radio(chemo)therapy for locally advanced head and neck squamous cell carcinomas offer some benefit in tumor control or survival. We did a thorough literature research on that topic. The results of several recently published studies are described, summarized, and reviewed. Patients with residual disease in clinical or radiographic examinations (CT or MRI scans) up to 3 months after completion of radiochemotherapy profit from neck dissections. In patients with an initial or delayed clinical complete remission after completion of radiochemotherapy, a neck dissection can be safely omitted. In conclusion, there is no longer evidence for a benefit of prophylactic post-radiochemotherapy neck dissections, but strong evidence for a therapeutic post-radiochemotherapy neck dissection in this group of patients.

[Peripheral branches of the facial nerve in the cheek and chin area. Anatomy and clinical consequences]. / Die peripheren Aste des N. facialis im Wangen-und Kinnbereich. Anatomie und klinische Konsequenzen.

The available descriptions of the innervation of the depressor anguli oris muscle and the peripheral distribution of the terminal branches of the marginal mandibular branch and buccal branches of the facial nerve are conflicting. Based upon dissections of 25 head halves we investigated the courses of the terminal branches of the marginal mandibular and buccal nerves. The marginal mandibular and buccal branches were found to form in the area of the mental foramen the mental and buccal plexus innervating the mimetic muscles by terminal nerve branches in the cheek area. The buccal plexus supplied the muscles of upper lip, cheek and nose. Furthermore, the depressor anguli oris muscle was also supplied by the buccal plexus. We also observed connections between marginal mandibular branch and mental nerve and between buccal branches of the facial nerve and buccal nerve of the trigeminal nerve. In case of injury to the marginal mandibular branch the depressor anguli oris muscle is not affected. Injury to the nerve branches of the depressor anguli oris muscle can be caused by operations or lesions in the area of the posterior border of this muscle.

[Evoked otoacoustic emissions and middle ear function]. / Evozierte otoakustische Emissionen und Mittelohrfunktion.

Transiently evoked otoacustic emissions (TEOAE) recorded in 98 ears were compared depending on the results of tympanometry. The values of middle ear pressure in patients without detectable TEOAE are significantly smaller compared to those of patients with detectable TEOAE. In cases of detectable TEOAE, the amplitudes and frequency components were compared to the results of tympanometry. When maximal compliances are shifted towards negative values of middle ear pressure, the amplitudes of TEOAE are reduced with a loss of low frequency components. Small compliance values result in reduced amplitudes of TEOAE with the loss of low frequency components. By means of cluster analysis in the scatter plot of middle ear compliance and pressure, a classification is obtained separating two groups representing significantly groups of patients with and without detectable TEOAE. Summing up, it must be stated that there is an effect of middle ear function on TEOAE which must be taken into consideration when TEOAE are used in clinical application.

[Isolated paralysis of the ramus marginalis mandibulae nervi facialis: clinical aspects, etiology, diagnosis and therapy. An overview]. / Die isolierte Parese des Ramus marginalis mandibulae nervi facialis: Klinik, Ursachen, Diagnostik und Therapie. Eine Ubersicht.

BACKGROUND: Disorders of lower lip in facial expression are mostly caused by functional impairment of the marginal mandibular branch of the facial nerve. In a typical case, active exposure of the incisors of the mandible is not possible and the lip appears distorted towards the healthy side. The most frequent cause of a lesion of the marginal mandibular branch is iatrogenic injury during operations in the mandibular or parotid region. DIFFERENTIAL DIAGNOSIS: Functional disorders of the platysma, congenital hypoplasia or aplasia of the lower lip muscles, and defective healing following facial palsy may lead to a similar disorder which, however, must be differentiated from an isolated paralysis of the marginal mandibular branch. TREATMENT: In addition to inactivation of the nerve branch on the opposite side, several surgical procedures have been described to achieve not only aesthetic, but also functional rehabilitation of lower lip expression. The present review gives an overview on the causes, clinical appearance, diagnosis, differential diagnosis, and therapy of unilateral isolated paresis of the marginal mandibular branch of the facial nerve.

[Studies of the course of the marginal branch of the facial mandibular nerve]. / Untersuchungen zum Verlauf des Ramus marginalis mandibulae nervi facialis.

BACKGROUND: In many operations involving the submandibular and lower cheek region, the mandibular branch of the facial nerve is in danger. METHODS: On the basis of 55 facial dissections, we classified the course of the nerve into one of three types. RESULTS: In about 66% of cases, the nerve runs below the angle and below the inferior border of the mandible. Typically, the mandibular branch consists of up to four major branches. The maximum distance between the lowest point of the mandibular branch and the inferior border of the mandible was 1.4 cm. We also studied the location of the nerve in relation to the facial vessels and the posterior facial vein. CONCLUSIONS: Incisions in the submandibular region should be performed at least 2 cm below the inferior border of the mandible. The nerve can be spared by ligature and by retracting the anterior facial vein.

Motor potentials of lower-lip mimetic muscles and distal arm muscles to cortical transcranial magnetic stimulation: the possibility of one-dimensional separation of two cortical representation areas.

The cortical representation of the abductor pollicis brevis muscle (APB) was investigated by transcranial magnetic stimulation (TMS) along the interaural line on the head surface in 17 healthy subjects. Comparing amplitudes of motor evoked potentials (MEPs) with those obtained by cortical TMS of lower-lip muscles, we found a considerable overlap between the areas from which reproducible MEPs of APB and lower-lip muscles could be elicited. However, there was a statistically significant separation of the two areas, the APB area being placed more medially. With regard to short examination procedures it can be concluded that a separation between distal arm and facial muscles is possible not only by two-dimensional cortical mapping procedures, but also by one-dimensional cortical TMS.

[3-dimensional representation of transient evoked otoacoustic emissions]. / 3-dimensionale Darstellung transient evozierter otoakustischer Emissionen.

A new method for the transformation of TEOAE signals into 3-dimensional diagrams is presented. The special transformation algorithm is based on a latency related frequency analysis of the cochlear response. The analysis and presentation are implemented in a C-programme. In a first clinical study 390 TEOAE signals from ears with and without hearing impairment were evaluated. For normal hearing the 3-dimensional diagram of TEOAE-signals is characterised by a typical wave form: with increasing frequency the latency of the cochlear response decrease. In the case of hearing loss there is an overall tendency to increasing wave latencies in comparison to normal hearing. An additional wave in the 3-dimensional diagrams of ears with tinnitus was observed. This characteristic is interpreted as an indicator of cochlea dysfunction. The 3-dimensional diagram promises to give a new aspect in the clinical interpretation of click-evoked otoacoustic emissions.