Analysis of dispersive interactions at polymer/TiAlN interfaces by means of dynamic force spectroscopy

The structural and electronic origins of the interactions between polycarbonate and sputter deposited TiAlN were analysed using a combined electron and force spectroscopic approach. Interaction forces were measured by means of dynamic force spectroscopy and the surface polarizability was analysed by X-ray photoelectron valence band spectroscopy. It could be shown that the adhesive interactions between polycarbonate and TiAlN are governed by van der Waals forces. Different surface cleansing and oxidizing treatments were investigated and the effect of the surface chemistry on the force interactions was analysed. Intense surface oxidation resulted in a decreased adhesion force by a factor of two due to the formation of a 2 nm thick Ti_0.21Al_0.45O surface oxide layer. The origin of the residual adhesion forces caused by the mixed Ti_0.21Al_0.45O surface oxide was clarified by considering the non-retarded Hamaker coefficients as calculated by Lifshitz theory, based on optical data from Reflection Electron Energy Loss Spectroscopy. This disclosed increased dispersion forces of Ti_0.21Al_0.45O due to the presence of Ti(iv) ions and related Ti 3d band optical transitions.

New amidinate complexes of indium(iii): promising CVD precursors for transparent and conductive In2O3 thin films

Heteroleptic and homoleptic In(iii)-amidinate complexes as promising CVD precursors for In₂O₃ thin films.

First Measurement of Electron Neutrino Appearance in NOvA

We report results from the first search for ν_{μ}→ν_{e} transitions by the NOvA experiment. In an exposure equivalent to 2.74×10^{20} protons on target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of 0.99±0.11(syst) events based on the Near Detector measurement. A secondary analysis observes 11 events with a background of 1.07±0.14(syst). The 3.3σ excess of events observed in the primary analysis disfavors 0.1π<δ_{CP}<0.5π in the inverted mass hierarchy at the 90% C.L.

Salivary gland scintigraphy in patients suffering from severe keratoconjunctivitis sicca. Evaluation of the viability of submandibular glands before and after transfer into the temporal fossa

Low tear production or elevated tear evaporation can lead to severe keratoconjunctivitis sicca. In patients with this disease, the transfer of an autologous submandibular gland into the temporal fossa is currently the most common surgical lacrimal gland substituting procedure.

AIM

We compared the pre- and postoperative viability of transferred submandibular glands.

PATIENTS, METHODS

Altogether 16 submandibular glands had been transferred in 12 patients. The graft's viability was evaluated before and 0.5-1, 1-6 and 8-12 months after transplantation by dynamic salivary gland scintigraphies after application of 40-50 MBq 99mTc-pertechnetate. Quantitative analysis was performed by calculation and comparison of the glandula submandibularis-to-background-ratio (SBR) and the transplant-to-background-ratio (TBR). The scintigraphic results were correlated with the clinical follow-up.

RESULTS

All grafts remained viable during clinical follow-up. Salivary gland scintigraphy yielded 15 true positive results and 1 false-negative result. Comparison of presurgical SBR and postsurgical TBR showed good correlation with the clinical course. In 10 patients at least one transplant-reduction was necessary due to excessive epiphora occurring averagely 8 months after transplantation.

CONCLUSION

Our results show that salivary gland scintigraphy very exactly reflects the morphological and biochemical postsurgical changes in a transferred submandibular gland. Thus, it is a reliable tool to exactly and objectively evaluate the viability of the grafts in the postsurgical course.

[Histological and immunohistochemical study of capsular contracture in an animal model--a comparison of two implants according to a modification of Wilflingseder's classification]

BACKGROUND

The influence of silicone implants on the formation of a periprosthetic capsule can be well examined in animal studies. New implant materials have been developed to reduce capsular contracture. In order to evaluate the capsule formation, Wilflingseder et al. developed a histological score system. Because of new knowledge in the development of capsular contracture, the Wilflingseder classification is no longer appropriate. Current references are not considered so that a modification is required.

MATERIAL AND METHOD

In a randomised, experimental animal study 31 mini-implants were implanted into the dorsum of female Wistar rats [17 smooth, 10 mL saline-filled silicone implants (Group A) and 14 titanium coated silicone implants (Group B)]. After 12 (group A/B12) or 36 (group A/B36) weeks, surgical removal of the implants with subsequent histomorphological and immunohistochemical examination of periprosthetic capsule formation was performed by 2 independent investigators in a double-blind manner.

RESULTS

An analysis of the studies showed that the inner synovia metaplasia and the infiltration by inflammatory cells such as lymphocytes, histiocytes, plasma cells and granulocytes are of crucial importance in the development of a fibrotic capsule. The occurrence of these factors correlated significantly with each other and influenced also significantly the capsule architecture depending on implant surface. An adjustment of the existing Wilflingseder classification system was evaluated. The current rating system contains the following parameters: capsule thickness and cell layers of the capsule, the thickness of the inner synovial metaplasia, collagen structure, presence of histiocytes and the incidence of inflammatory cells. According to this classification, titanium-coated implants show an advantage in terms of the formation of capsular contracture.

CONCLUSION

In 1974 Wilflingseder et al. developed a classification system for capsular contracture which is no longer appropriate, since current histological and immunohistochemical findings are not mentioned. Our study presents a new system which includes the latest insights into the development of capsular contracture and provides an objective classification of histological changes. Furthermore, we were able to show that titanium-coated implants are a promising approach in the reduction of capsular contracture.

[A comparison of the use of electrochemical treatment and radio frequency ablation in porcine liver]

BACKGROUND

Radiofrequency ablation (RFA) and electrochemical treatment (ECT) are competing methods of intrahepatic ablation. We compared RFA and ECT in a perfusion model and in vivo in pigs.

MATERIAL AND METHODS

Twenty-seven fresh porcine livers were obtained from a slaughterhouse and placed ex vivo into a perfusion model. RFA or ECT electrodes were inserted under ultrasound guidance in perivascular locations at a distance of 10 mm from a portal vessel. A total of 83 areas of ablation were created. In vivo ablations were performed at perivascular sites in 10 laparotomised pigs. Four areas of ablation were created per liver using RFA or ECL. Inflammatory parameters, liver values and cytokine levels were determined before and after surgery and on days 1, 3 and 7 after surgery. On day 7, the livers were harvested and specimens were analysed histo-logically by independent experts.

RESULTS

In 29% of 59 ex vivo RFA ablations, the target temperature was not reached and the procedure was discontinued. Intact hepatocytes were detected in close proximity to 70 % of the vessels within necrotic areas. In 24 ECT applications, treatment time depended on the charge delivered and ranged between 50 min at 150 coulombs (C) and 200 min at 600 C. The pH level was 0.9 at the anode and 12.2 at the cathode. ECT always led to complete perivascular necrosis and vessel wall destruction. The animals had an in vivo -median weight of 39.5 kg. Neither RFA nor ECT caused major complications such as bleeding, bile leaks or abscesses. Treatment time was 67 min (200 C) for ECT and 12.4 min for RFA. In 73% of the cases, RFA led to incomplete perivascular areas of necrosis. ECT induced complete perivascular necrosis and vessel wall destruction. On day 1 after surgery, both ECT and RFA were associated with a significant increase in monocyte, C-reactive protein and aspartate aminotransferase levels. Leukocyte counts were elevated only after ECT, bilirubin levels only after RFA. There were no significant differences in interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and IL-1β.

CONCLUSION

Both RFA and ECL are safe methods of intrahepatic ablation. As a result of a heat sink effect of blood flow in nearby vessels, RFA leads to incomplete necrosis in perivascular sites both ex vivo and in vivo. ECT has the disadvantage of long treatment times but the advantage of lower costs since the platinum electrodes are reusable. Without a reduction in liver perfusion, the central application of RFA in close proximity to vessels should be considered problematic.

[Stromal tumour of uncertain malignant potential of the prostate (STUMP) - a case report]

A prostatic stromal tumour of uncertain malignant potential (STUMP) is a non-epithelial, mesenchymal spindle-cell tumour that can be classified as a specialised stromal tumour of the prostate. Although in most cases STUMP is not of an aggressive nature, occasional cases have been documented with an extension into adjacent tissues or recurrence after resection. A minority of cases develop a sarcomatous dedifferentiation.We report the case of a 53-year-old male with symptoms of febrile prostatitis. After consolidation we performed TUR-P due to urinary retention. Finally, we made the pathological diagnosis of prostatic STUMP. The patient is being seen -frequently in our clinic to take prostate biopsies to exclude a progression into a stromal sarcoma (active surveillance). After 13 months the STUMP is still detectable, but with no signs of sarcoma.

[Analysis of 18F-FDG uptake pattern in PET for diagnosis of aseptic loosening versus prosthesis infection after total knee arthroplasty. A prospective pilot study]

The AIM of this prospective study was to identify a typical pattern for fluorodeoxyglucose (18F-FDG) uptake in positron emission tomography (PET) to differentiate aseptic loosening (tibial and / or femoral component) from prosthesis infection in painful knee prosthesis.

PATIENTS, METHODS

20 patients with painful knee prosthesis underwent PET imaging to evaluate aseptic loosening / prosthesis infection of their knee prosthesis. The interface between bone and surrounding soft tissue or bone was divided into 3 segments each for both the femur and the tibia and in addition for 4 segments reflecting the surrounding periprosthetic soft tissue. FDG uptake in each of the segments was scored (0-3) by two independent observers. The final diagnosis was based on operative findings with subsequent microbiological culture and histological examination.

RESULTS

After surgical revision 6 femoral components and 5 tibial components were found to be loose and prosthetic infection was present in 9 prostheses. In 8 of 9 infected prostheses loosening of the femoral und tibial component occurred. There was no statistically significant correlation between the standardised uptake within each of the segments and the diagnosis of aseptic loosening or prosthesis infection. A differentiated qualitative and quantitative FDG-PET result interpretation divided into five categories was developed. Specificity / sensitivity / positive predictive value / negative predictive value were 93% / 83% / 83% / 93% for aseptic loosening of the femoral component, 87% / 80% / 67% / 93% for aseptic loosening of the tibial component and 82% / 89% / 80% / 90% for infection.

CONCLUSION

This pilot study shows that FDG-PET is a promising diagnostic tool for patients with painful knee prostheses. There is a good correlation between PET images and the intraoperative and pathology findings. Its clinical value, however, warrants further evaluation in a larger patient population.

Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam

This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27 x 10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336+/-14 events. The data are consistent with nu(mu) disappearance via oscillations with |Delta(m)2/32|=2.74 +0.44/-0.26 x10(-3)eV(2) and sin(2)(2theta(23))>0.87 (68% C.L.).

Enoximone maintains intestinal villus blood flow during endotoxemia

BACKGROUND

The objective of this study was to determine the effects of a continuous infusion of the phosphodiesterase inhibitor enoximone on mucosal villus blood flow in a normotensive model of endotoxemia.

METHODS

Twenty-four anesthetized and ventilated rats underwent laparotomy and a ileal portion was exteriorized and opened by an antimesenteric incision. The ileal segment was fixed on a plexiglass stage with the mucosal surface upward. Microcirculatory parameters were assessed by intravital videomicroscopy. The animals were randomly assigned to receive one of three treatments: infusion of Escherichia coli lipopolysaccharides (LPS, 2 mg/kg/h) without phosphodiesterase inhibitor pretreatment (LPS group); or infusion of LPS with enoximone pretreatment (10 microg x kg(-1) x min(-1), start 30 min before LPS infusion, enoximone group), or infusion of an eqivalent volume of NaCl 0.9% (control group). Macrohemodynamic parameters (MAP, HR) and microhemodynamic parameters of ileal mucosa (mean diameter of central arterioles = DA, and mean erythrocyte velocity within the arterioles = VE) were measured 30 min before and at 0, 60, and 120 min after induction of endotoxemia. Mucosal villus blood flow was calculated from DA and VE.

RESULTS

In this normotensive endotoxemia model MAP remained stable in the control and the LPS group but significantly decreased in the enoximone group. The endotoxin-induced decrease of VE and DE of central arterioles of mucosal villi could be prevented. Thus, mucosal villus blood flow did not decrease compared to the LPS group.

CONCLUSIONS

Our results indicate that enoximone during an early stage of sepsis contributes to systemic hypotension but prevents mucosal hypoperfusion.

MR arthrography: pharmacology, efficacy and safety in clinical trials

OBJECTIVE

A meta-analysis was carried out of clinical trials published between 1987 and 2001 in respect of the clinical pharmacology and safety as well as the diagnostic efficacy of gadolinium-DTPA (Gd-DTPA) for direct intra-articular injection before MRI examination.

DESIGN

Scientific papers (clinical, postmortem and experimental studies) and information from the manufacturer regarding intra-articular injection of Gd-DTPA that addressed questions of mode of action, optimal concentration and dose, elimination and safety were reviewed. Clinical studies were classified according to their study design. The sensitivity, specificity and accuracy of MR arthrography (MRA) were compared with a "gold standard" (arthroscopy, arthrotomy) and other radiological evidence for different joints.

RESULTS

Fifty-two clinical studies of the overall 112 studies addressed aspects of diagnostic efficacy of MRA in patients or in healthy volunteers. The shoulder was the most assessed joint (29 of 52 studies). Good (>80%) or even excellent (90-100%) sensitivity, specificity and accuracy were found for MRA in most indications, especially for the shoulder and knee joints and induced extension of rotator cuff lesions, labrum abnormalities and postoperative meniscal tears. Two millimoles per liter has proven to be the best concentration for intra-articular administration of Gd-DTPA. After passive complete diffusion from the joint within 6-24 h, complete and rapid renal elimination takes place after intra-articular injection. Local safety proved to be excellent after intra-articular administration of Gd-DTPA. Regarding systemic tolerance almost no side effects have been reported, but the same safety considerations apply for intra-articular administration of Gd-DTPA as for intravenous injection.

CONCLUSIONS

The diagnostic efficacy of intra-articular MRA in most clinical conditions affecting major joints is greater than that of plain MRI. In some diagnostic problems MRA achieves almost the same sensitivity and specificity as the surgical gold standard. Given a sterile application, the intra-articular administration of Gd-DTPA in a concentration of 2 mmol/l prior to MRI is a safe procedure.

Four-dimensional imaging and quantitative reconstruction to analyse complex spatiotemporal processes in live cells

Live-cell imaging technology using fluorescent proteins (green fluorescent protein and its homologues) has revolutionized the study of cellular dynamics. But tools that can quantitatively analyse complex spatiotemporal processes in live cells remain lacking. Here we describe a new technique--fast multi-colour four-dimensional imaging combined with automated and quantitative time-space reconstruction--to fill this gap. As a proof of principle, we apply this method to study the re-formation of the nuclear envelope in live cells. Four-dimensional imaging of three spectrally distinct fluorescent proteins is used to simultaneously visualize three different cellular compartments at high speed and with high spatial resolution. The highly complex data, comprising several thousand images from a single cell, were quantitatively reconstructed in time-space by software developed in-house. This analysis reveals quantitative and qualitative insights into the highly ordered topology of nuclear envelope formation, in correlation with chromatin expansion - results that would have been impossible to achieve by manual inspection alone. Our new technique will greatly facilitate study of the highly ordered dynamic architecture of eukaryotic cells.