Quantification of silane molecules on oxidized silicon: are there options for a traceable and absolute determination?

Organosilanes are used routinely to functionalize various support materials for further modifications. Nevertheless, reliable quantitative information about surface functional group densities after layer formation is rarely available. Here, we present the analysis of thin organic nanolayers made from nitrogen containing silane molecules on naturally oxidized silicon wafers with reference-free total reflection X-ray fluorescence (TXRF) and X-ray photoelectron spectroscopy (XPS). An areic density of 2-4 silane molecules per nm(2) was calculated from the layer's nitrogen mass deposition per area unit obtained by reference-free TXRF. Complementary energy and angle-resolved XPS (ER/AR-XPS) in the Si 2p core-level region was used to analyze the outermost surface region of the organic (silane layer)-inorganic (silicon wafer) interface. Different coexisting silicon species as silicon, native silicon oxide, and silane were identified and quantified. As a result of the presented proof-of-concept, absolute and traceable values for the areic density of silanes containing nitrogen as intrinsic marker are obtained by calibration of the XPS methods with reference-free TXRF. Furthermore, ER/AR-XPS is shown to facilitate the determination of areic densities in (mono)layers made from silanes having no heteroatomic marker other than silicon. After calibration with reference-free TXRF, these areic densities of silane molecules can be determined when using the XPS component intensity of the silane's silicon atom.

Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy.

The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.

Bone grafting in oblique versus prepared rectangular uncontained glenoid defects in reversed shoulder arthroplasty. A biomechanical comparison.

BACKGROUND: How the shape of the glenoid defect being reconstructed influences stability in reversed shoulder arthroplasty has never been evaluated. The purpose of this study was to compare the reconstruction of two different shaped defects in reversed shoulder arthroplasty. METHODS: Two groups (ten Sawbone scapulae each) of oblique- and rectangular-shaped glenoid defects were tested biomechanically. On the anterior half of the glenoid, bony defects (rectangular and oblique shaped) were prepared and reconstructed subsequently with a graft and reversed shoulder arthroplasty. As a control group, Sawbones without glenoid deficiency were used. In addition, these tests were reproduced in cadavers. FINDINGS: In Sawbones, no significant difference in initial stability was found between the two groups (p>0.05). Additionally, in the cadaver tests no significant difference was found between the groups with different defects (p>0.05). During the preparation, macroscopic loosening of the oblique bone grafts was found in three cases after the performance of the reversed shoulder arthroplasty due to the lack of medial support. The localization of the highest micromotion were measured primarily between the scapula bone and the graft compared to the measured micromotions between glenoid implant and the graft. INTERPRETATION: If the oblique-shaped bone graft was secured under the baseplate, the rectangular defect preparation did not show a significantly higher primary stability. However, the advantage of medial support in rectangular defects leads to more stability while placing the bone graft and baseplate during the surgical technique and should therefore be considered a preferable option.

Influence of different peg length in glenoid bone loss: A biomechanical analysis regarding primary stability of the glenoid baseplate in reverse shoulder arthroplasty.

BACKGROUND: There is no biomechanical basis to determine the influence of different length of the central peg of the baseplate anchored within the native scapula in glenoid defect reconstruction in cases of degenerative or posttraumatic glenoid bone loss in reversed shoulder arthroplasty. OBJECTIVE: The purpose of this study was to analyse the stability of different peg lengths used in glenoid bone loss in reversed shoulder arthroplasty. METHODS: Different lengths of metaglene pegs with different depths of peg anchorage performed with or without metaglene screws in sawbone foam blocks were loaded in vertical and horizontal directions for differentiating load capacities. Simulated physiological loadings were then applied to the peg implants to determine the limits of loading in each depth of anchorage. RESULTS: The loading capacity of the implant was reduced as less of the peg was anchored. The vertically loaded implants showed a significantly higher stability, in contrast to those loaded horizontally at a corresponding peg length and depth of anchorage (p < 0.05). The tests revealed that the metaglene screws are more essential for primary stability than is the peg particularly in the vertically directed loadings (2/3 anchored: peg contributed to 28% of the stability, 1/3 anchorage: peg contributed to 12%). Under the second test conditions, the lowest depth of peg anchorage (1/3) resulted in 322 Newtons [N] in the long peg with a vertical loading direction, and in 130 N in the long peg with a horizontal loading direction (p < 0.05). CONCLUSION: The pegs should be anchored as deeply as possible into the native scapula bone stock. The metaglene screws play a major role in the initial stability, in contrast to the peg, and they become more important when the depth of the peg anchorage is reduced. If possible, four metaglene screws should be used in cases of uncontained bone loss to guarantee the highest stability.

Inhibition of the conjugation of PABA with glycine in vitro by sulfamoyl benzoic acids, sulfonamides, and penicillins and its relation to tubular secretion.

Elimination of drug molecules via tubular secretion is an important pharmacokinetic parameter especially for oral dosage forms where an extremely short half-life would prevent their application. We have studied the inhibition in vitro of the glycination of p-aminobenzoic acid (PABA) using rat liver microsomal preparations. The I50 values, the concentration of the inhibitor that leads to 50% inhibition of glycine conjugation of PABA as compared to the control, have been determined for sulfamoyl benzoic acids, sulfonamides, and penicillins. Statistically significant regression equations were derived explaining the observed variation in I50 values as a function of lipophilicity and steric bulk of the substituents for the combined set of sulfamoyl benzoic acids and sulfonamides (n = 33). For the penicillins studied, only steric effects seem to be important for the explanation of the I50 values. Finally, regression analysis and the use of neural networks allowed the classification of compounds by their in vitro I50 values as being tubular secreted or not. Therefore, it can be concluded that the inhibition in vitro of the glycine conjugation of PABA is a useful model for the estimation of tubular secretion and drug interaction potential of acidic drug molecules in this process in vivo.

Therapy of steroid-refractory acute GVHD with CD52 antibody alemtuzumab is effective.

The efficacy and safety of CD52 antibody alemtuzumab to treat severe acute GVHD in 18 consecutive patients refractory to standard high-dose corticosteroid therapy is reported. Patients (age range 13-68 years) had developed acute GVHD grade III and IV with gut and/or liver involvement after stem cell transplantation from family donors (n= 7) or HLA-matched unrelated donors (n=11), including five donors with one or two HLA mismatches. Initially, in three patients, start doses of alemtuzumab in the range of 70-80 mg were applied and repeated after 3 to 4 weeks. Impressive responses were seen, but virus reactivation and bacterial infections were frequent. In an attempt to reduce this complication, the next nine patients received a reduced starting dose of 20-33 mg, and the last six patients received 3-13 mg repeated every 2-3 weeks. Seventeen of 18 patients responded to alemtuzumab, six patients are alive with a median follow-up of 108 weeks. Chronic GVHD was observed frequently. Although pronounced lymphocyte depletion requiring close monitoring for signs of infections seems inevitable for efficacy, alemtuzumab given in moderate doses has a substantial activity not only in intestinal but also in severe acute GVHD of the liver.

[Reintervention in recurrent carcinoma of the large bowel (author's transl)]. / 27. Der Zweit-und Mehrfacheingriff beim Coloncarcinom

Reintervention has a good change of success in recurrent of carcinoma of the sigma and colon. Early detection is essential for reintervention to be successful, and meticulous follow-up is therefore necessary in all patients operated on for tumors: follow-up examinations can best be carried out at a special tumor clinic. Since 1964,-42 patients have undergone reintervention for recurrences. In 50% of them the condition was found to be inoperable. On the other hand, 14 of 21 patients in whom reintervention was successful are still alive. Adjuvant therapy such as radio therapy or cytostatics is rarely administered, but should be employed more in the future.

[Iatrogenic injuries of the human bile duct]. / Die iatrogene Gallenwegsläsion

The problems of diagnosis and treatment of iatrogenic injuries to the extrahepatic biliary tract are discussed, reviewing 31 own cases. End-to-end anastomoses should only be performed in immediatly detected lesions. In cases of delayed diagnosis only biliodigestive anastomoses, e.g. hepaticojejunostomy, are indicated to avoid stenosis of the anastomosis. Injuries to the biliary tract can be reduced by early diagnosis of bilary diseases and correct intraoperative diagnostic means.

Chemotactic and phagocytic function of peripheral blood polymorphonuclear leucocytes in newborn foals.

Chemotactic and phagocytic responsiveness of peripheral blood polymorphonuclear leucocytes (PMNLs) from 11 foals were analysed immediately after birth (pre-colostral) and at different times after colostrum ingestion. The number of foal PMNLs per microscopic field that had migrated through the filter in chemotaxis and the number of yeast particles ingested per foal PMNL in phagocytosis were significantly lower when tested with foal plasma before colostrum ingestion (chemotaxis, 2.0 +/- 0.55 (s.e.m.); phagocytosis, 0.98 +/- 0.352) than in tests 4 or more days after colostrum ingestion (chemotaxis, 17.6 +/- 3.88; phagocytosis, 3.87 +/- 0.410; P less than or equal to 0.005). A similar functional deficiency was found in foal PMNLs tested with pre-colostral foal plasma when compared to tests of the same cells with mare plasma (chemotaxis, 11.6 +/- 2.91; phagocytosis, 3.94 +/- 0.269; P less than or equal to 0.005). PMNLs from neonatal foals responded with normal functions to plasma from normal adult horses. Results of both assays suggest that pre-colostral foal PMNLs are functionally mature but the expression of their chemotactic and phagocytic functions depends on the humoral source of chemotactic and opsonic factors.