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Kurzfassung Durch die Variation der Nitrocarburierparameter sind die Eigenschaften von nitrocarburierten Bauteilen, insbesondere im Hinblick auf Verschleiß, in weiten Bereichen veränderbar. Aber auch der Werkstoff und der Vorwärmebehandlungszustand haben einen Einfluss auf das Nitrocarburierergebnis. Um Nitrocarburierschichten reproduzierbar an den verschiedenen Bauteilen in den unterschiedlichsten Öfen zu erzeugen, ist sowohl eine geeignete Mess- und Regelungstechnik als auch eine Wissens- und Datenbank, wann welche Randschicht mit welcher Eigenschaft entsteht, notwendig. Die vorliegende Arbeit beschäftigt sich mit dem Aufbau einer solchen Datenbank. Durch sensorgeregelte Nitrier- und Nitrocarburierprozesse wurde das Dreistoffsystem Fe-N-C im Temperaturbereich des Nitrocarburierens an fünf Stählen experimentell untersucht. Die erhaltenen Daten bilden die Grundlage für das Expertensystem Nitrocarburieren.

Objective To report the results of a clinical study investigating the diagnosis of malignant and dysplastic bladder lesions by protoporphyrin IX (PPIX) fluorescence and to compare them with those from earlier studies. Patients and methods The study included 55 patients with suspected bladder carcinoma (at initial diagnosis or at tumour follow-up visits); 130 bladder biopsies from 49 patients were classified by pathological analysis. All patients received an intravesical instillation of 50 mL of a 3% 5-aminolaevulinic acid (ALA) solution a mean of 135 min before cystoscopy, which was then performed under white and blue light. Malignant/dysplastic lesions showing red fluorescence under blue-light excitation were noted and the increase in detection rate calculated. Results There were 63 benign and 67 malignant/dysplastic areas biopsied; 10 malignant/dysplastic lesions (four transitional cell carcinoma, two carcinoma in situ, four dysplasia) were not detected during routine white-light cystoscopy but were identified under blue light. Fluorescence cystoscopy improved the overall diagnosis of malignant/dysplastic bladder lesions by 18% over standard white-light cystoscopy. The improvement was greater for dysplastic lesions and carcinoma in situ (50%). However, the improvement over standard cystoscopy was less than that found by other groups. Conclusion The ALA-based fluorescence detection system significantly enhanced the diagnosis of malignant/dysplastic bladder lesions. However, determining the optimum drug exposure time requires further investigation using well-characterized instrumentation and study protocols, which would then allow comparison of the results from different groups.

Infections due to carbapenem-resistant Enterobacteriaceae (CRE) represent a growing problem nationally, are difficult to treat, and are associated with high mortality rates. Features of CRE infection within Connecticut, a nonendemic area, have not been described in the medical literature. We report a case series of five patients with CRE isolates who were treated at Hartford Hospital in Hartford, Connecticut from 2011-2013. CRE isolates included three Klebsiella pneumoniae, one Klebsiella oxytoca, and two E. coli. Three isolates were obtained from urine cultures, one from respiratory culture, and one from blood and wound cultures. Four patients survived the hospital course, including three patients who had a hospital stay of100 days. In this nonendemic hospital, CRE infections were identified mainly in patients with multiple comorbidities who underwent catheter placement and surgical procedures, had contact with the health care system in the preceding 90 days, and tended to have prolonged, complicated hospital courses.

We have investigated the somatic activity of the maize Activator (Ac) element in haploid and diploid aspen with the objective of developing an efficient transposon-based system for gene isolation in the model tree species Populus. It was shown that Ac is reinserted, frequently into or near coding regions in aspen, and therefore can be used for gene tagging studies. A number of phenotypic variants were also found following transformation of constructs harbouring the rolC gene. Comparative analyses of T-DNA flanking regions of variants and wild type lines indicate that T-DNA insertion has occurred in or near coding regions. However, the frequency of T-DNA insertion into genes is about one half of the frequency of Ac insertion hitting coding sequences. The results obtained give a proof-of-concept for transposon tagging in a tree system. Given the long generation cycles in tree species, gene tagging strategies are practical only to obtain dominant gain-of-function mutants that do not require selfing or test crossing. In order to obtain recessive loss-of-function mutants, we have regenerated haploid lines from immature pollen. These lines were successfully transformed with a construct containing the rolC transgene from Agrobacterium rhizogenes and Ac element from maize. The results indicate that Ac is also active in haploid aspen and hence can be used in general for gene tagging in trees.

In this study, the results of four different field experiments concerning the speciation of iron and the concentrations of some other chemical compounds in cloudwater samples are compared to one-another. Hydrogen peroxide concentrations were higher during campaigns, conducted at sites not much influenced by anthropogenic emissions as compared to those conducted at more polluted areas. In contrast, percentages of S(IV) in the cloudwater were lowest at the rural sites and highest at the sites polluted by human activities, indicating a consumption of hydrogen peroxide in the oxidation reaction with S(IV). The concentration of dissolved iron was observed to correlate with the percentage of S(IV), which may be an essential point for the reductive dissolution of oxidic iron compounds of the aerosol particles. As far as the speciation of the dissolved iron is concerned, it became obvious that the percentage of Fe(III) is anticorrelated to the concentration of dissolved iron. This clearly shows the important effect of the chemical and/or photo reductive ways of dissolving the iron(III)-compounds from the aerosol particles. However, a correlation between the pH-value and hydrogen peroxide was observed.

The Fe(II)/Fe(III)-partition in cloudwater samples collected during two field campaigns is evaluated. It turned out that the simultaneous occurrence of complexing and reducing substances in the atmosphere and the cloud processing increase the solubility of iron compounds present in aerosol particles. A correlation between the concentration of iron(II) in the liquid phase and the intensity of the solar irradiation was observed for most of the cloudwater samples. This could be due to the fact that both the photochemical reduction of the iron(III) complexes and the photochemical reductive dissolution of iron(III)(hydr)oxides are depending on the pH-value. Iron(II) seems to be oxidised back to iron(III) preferably by hydrogen peroxide during the night. Positive correlations were received e.g. between the concentration of dissolved iron and the concentration of oxalate and between the percentage of iron(III) and the concentration of hydrogen peroxide. A negative correlation was found e.g. between the concentration of dissolved iron and the pH-value. The uncertainty of the whole process of sampling and analysis was investigated and the conformity of the results was satisfying considering the sometimes difficult conditions during a field campaign.

Wood formation and structure of 3-year-old 35S-rolC transgenic aspen (Populus tremula L. × tremuloides Michx.) were compared with the situation in non-transformed control aspen trees. The transgenics are characterized by reduced shoot growth and an earlier bud break. Their wood formation did not immediately follow bud break and leaf development but occurred after some delay, about the same time as wood formation was initiated in the control trees. Quantitatively, the wood structure of the transgenics and of the non-transformed controls was not significantly different; therefore the dwarfism of the transgenics is very likely due to a reduction in cell number. Atypical formation of latewood led to the assumption that the differentiation of cells is decelerated. Additionally, cells lacked both secondary walls and normal lignification, and discoloration of the wood and the formation of tyloses were conspicuous in all transgenics. In contrast, they did not occur in the non-transformed control aspen trees. The observations are discussed in relation to the widely accepted auxin hypothesis. It is suggested that 35S-rolC transgenic aspen trees may be a useful model to study the regulatory mechanisms of wood formation.

A relatively rapid 3-step fractionation method has been developed for the isolation of human alpha-fetoprotein from culture fluids of HepG2 cells applicable to large volumes. The protein exists as a complex with lipids or lipoproteins but an ethanol precipitation step is effective in separating it. Yields of 50-60% can be obtained from culture fluid containing 30-40 microg/ml. A minor fraction that appears to be a proteolytic product of the AFP is present in the final product.

This study demonstrates that oxalate has a strong inhibiting effect onFe-catalyzed S(IV) oxidation by oxygen in aqueous solution. While thepseudo-first order rate constant of S(IV) oxidation was determined to be1.6 × 103 M-1 s-1 in experimentswithout oxalate, the oxidation of S(IV) was totally inhibited at a molarconcentration ratio of iron:oxalate = 1:5 at an oxalate concentration of 4μM. Under these conditions, the Fe(II)/Fe(III) ratio remained nearlyconstant during the observed reaction time. The determined rate constants wereindependent of the initial oxidation state of iron. However, with increasingconcentrations of oxalate, a longer induction period is observed forexperiments with iron initially in the Fe(II) oxidation state.

We study a special dual form of a convex minimization problem in a Hilbert space, which is formally suggested by Fenchel dualityand is useful for the Dykstra algorithm. For this special duality problem, we prove that strong duality holds if and only if the collection of underlying constraint sets {C1,...,Cm} has the strong conical hull intersection property. That is, $$\left( {\mathop \cap \limits_1^m C_i - x)^ \circ = \sum\limits_1^m {(C_1 - x} } \right)^ \circ {\text{, for each }}x \in \mathop \cap \limits_1^m C_1$$ where D° denotes the dual cone of D. In general, we can establish weak duality for a convex minimization problem in a Hilbert space by perturbing the constraint sets so that the perturbed sets have the strong conical hull intersection property. This generalizes a result of Gaffke and Mathar.

Autoimmune pancreatitis (AIMP) is a recently described clinical entity causing chronic pancreatitis. It often presents with diffuse enlargement of the pancreas and/or a focal mass at the head of the pancreas causing common bile duct obstruction and jaundice. In most instances, AIMP is mistaken for pancreatic cancer. A number of laboratory abnormalities such as positive antinuclear antibody, hypergammaglobulinemia, and antibody to carbonic anhydrase are often present in these patients. Currently, pancreatic biopsy demonstrating characteristic histopathologic changes is essential to establish the diagnosis. We report the first case of AIMP presenting as a pancreatic tail mass and lower gastrointestinal bleed.

Purpose: We validate the usefulness of laser-induced autofluorescence for the detection of bladder carcinoma.Materials and Methods: We obtained and analyzed fluorescence spectra from 75 patients in whom bladder cancer was suspected. Tissue fluorescence was excited by a nitrogen laser using a quartz optical fiber placed in gentle contact with the area of interest. The laser-induced autofluorescence spectrum was recorded using an intensified optical multichannel analyzer system. Spectra were corrected for the spectral response of the optical system, and the ratios of laser-induced autofluorescence intensities (I) at 385 and 455 nm. (I385/I455) were determined. We had previously established this ratio as a diagnostic algorithm. We included only suspicious bladder lesions (erythematous, edematous, raised and so forth) that were difficult to diagnose by cystoscopy as well as areas from which random biopsies were obtained. The fluorescence ratio algorithm was applied to 130 bladder areas.Results: Of the...

The placebo effect will have a growing importance in the field of nuclear medicine as the potentials for palliative therapy with internal sources are realized. It is important for nuclear medicine physicians and their colleagues to be familiar with the role of placebo responses in clinical trials, especially when such trials involve the subjective assessment of pain. A summary of the literature on the placebo effect in pain studies is presented in which traditional values for placebo responses are contrasted with more current thinking in the field. The few published double-blind studies of pain relief after treatment with radiotherapeutic agents are summarized specifically with respect to their cited placebo response.

Demineralization has been shown to foster osteoinductive properties of cortical bone grafts, yet little is known about the process of demineralization and how to control it. The purpose of this study was to investigate the process of cortical bone demineralization by using scanning electron microscopy to evaluate how hydrochloric acid demineralizes cortical bone. Results showed that in the demineralization of diaphyseal cortical bone specimens using hydrochloric acid, a uniformly thick circumferential band of demineralized bone matrix surrounds an inner undecalcified bone core as the process of demineralization occurs. The interface between the demineralized and mineralized section of the bone specimens was extremely sharp. This interface between demineralized and undemineralized bone was noted to advance as a reaction front with increasing demineralization which resulted in continuous shrinkage of the inner cortical bone core. This study suggests that cortical bone demineralization can be best described using an advancing reaction front theory, and this explanation can be used for implementation of the concept of controlled demineralization.

Purpose: We assessed the ability of laser induced autofluorescence to differentiate malignant from nonmalignant bladder lesions.Materials and Methods: We studied 53 patients with bladder cancer undergoing mucosal biopsies or transurethral resection of a bladder tumor. A quartz optical fiber was advanced through the working channel of a cystoscope and placed in gentle contact with the bladder. Tissue fluorescence was excited by 337 nm. light pulses (nitrogen laser). One fiber was used for transmission of the excitation and emission (fluorescence) light. An optical multichannel analyzer system was used to record fluorescence spectra of the sites of interest.Results: We analyzed the fluorescence spectra of 114 bladder areas (1 carcinoma in situ as well as 28 malignant, 35 inflammatory, 7 dysplastic, 1 squamous metaplastic and 42 normal areas). These lesions included 44 difficult to diagnose suspicious tumors (11 malignant and 33 nonmalignant). We developed an algorithm that used the I385:I455 nm. flu...

We investigated the kinetics of hydrochloric acid demineralization of human cortical bone with the objective of developing a method of controlled demineralization for structural bone allografts. It is known that the demineralization of cortical bone is a diffusion rate limited process with a sharp advancing reaction front. The demineralization kinetics of human cortical bone, described as the advance of the reaction front versus immersion time, were determined by measuring extraction of bone mineral in both planar and cylindrical geometries. Mathematical models based on diffusional mass transfer were developed to predict this process. The experimental data fit well with the behavior predicted by the model. The model for planar geometry is applicable to controlled demineralization of cortical bone allografts of irregular shapes such as cortical struts. The model for cylindrical geometry is appropriate when curved surfaces are involved such as in diaphyseal bone allografts. This method of demineralization has direct application to clinical modification of cortical bone allografts to potentially enhance their osteoinductive properties.

Background and Objective Surgical reconstruction of bony defects in the maxillofacial region involves fixation of bony fragments with mini and micro plates. Bone stabilization during hole drilling is often challenging due to the need to apply pressure when using a conventional mechanical Hall drill. In addition, fragmentation of the fragile bones may occur and complicate the reconstruction. The pulsed Er:YAG laser offers an attractive alternative drilling modality because it does not require physical contact with the bone in order to drill holes, cuts bone with minimal thermal damage, and allows precise control of bone cutting. The objective of this study was to investigate the pulsed Er:YAG laser as an alternative to the mechanical bur by comparing bone healing using both modalities. Study Design/Materials and Methods Bone healing in an inferior border defect of the rat mandible was examined using either an Er:YAG laser or a mechanical but for drilling. The healing of osteotomies in facial bones and of screw holes for plate stabilization of free bone fragments was studied. Results All defects healed by 4 weeks postoperatively. Histologic evaluation demonstrated no difference in the amount of newly formed woven bone at the osteotomy site or screw holes made by either the laser or the drill. The extent of thermal damage at the osteotomy sites was comparable in laser and mechanically cut bone fragments. Conclusions On the basis of this study we suggest that the Er:YAG laser can be used clinically in thin, fragile bones in the maxillofacial region. © 1996 Wiley-Liss, Inc.

Background and Objective To determine the survival of in vitro retinal pigment epithelium (RPE) cells subjected to laser-generated stress transients (shock waves) and compare it to that of other cell lines. Study Design/Materials and Methods Normal and transformed human retinal pigment epithelium cell lines were used. The cells were imbedded in a gel to prevent motion and cavitation and located in a thin layer at the bottom of a pipette tube closed at one end by a polyimide film. Stress transients were generated by pulsed excimer laser (193 nm and 248 nm wavelength) ablation of the polyimide film. Cell survival, compared to that of unirradiated cells, was assessed by counting surviving cells. The stress was varied from 300 to 740 bars and the number of shock wave pulses applied varied from 5 to 150. Results Cell survival decreased sharply at the higher stresses but some cells always survived. The lowest survival rate was 50%. Increasing the number of shock wave pulses did not increase cell killing after 20 pulses, demonstrating a saturation effect. In contrast to the transformed cell line, normal cells could not be killed at the highest stress available to us. Conclusion The susceptibility of RPE cells to damage by stress waves varies with cell line. Transformed retinal pigment epithelium cells are more susceptible than normal ones. Saturation of the damage versus number of pulses is observed and a threshold-like behavior for cell killing versus stress is found. Because at least 50% of the cells survived, normal cell growth can serve to replenish damaged cells. © 1996 Wiley-Liss, Inc.

Massive cortical autografts and allografts have been found to incorporate into host bone very slowly and thus are subject to complications such as fatigue fracture and infection. In order to understand and improve the process of osteogenesis in these types of bone grafts, a new experimental model was developed using bone discs from rat calvaria prepared by demineralization and drilling of 0.5 mm diameter holes with a pulsed, 2.94 microns wavelength Erbium:Yttrium-Aluminum-Garnet laser. Four types of bone discs were analyzed: untreated (Type I), demineralized (Type II), laser-ablated (Type III), and laser-ablated then demineralized (Type IV). The discs were transplanted into a subcutaneous site in adult Sprague-Dawley rats and followed for as long as 6 weeks. Histologic analysis of the discs at weekly intervals with use of hematoxylin and eosin staining confirmed the presence of new bone growth in Type-II and Type-IV discs. The amount of new bone growth in each disc was estimated by determining the mineral x-ray attenuation coefficient, which is proportional to mineral density, from digitized radiographs of the discs. The results showed that the processes of demineralization (P < 0.001) and laser ablation with demineralization (p < 0.05) were both significant in enhancing new bone growth in this model. This study demonstrated that osteoinduction can be fostered in cortical bone through the processes of demineralization and laser ablation. To the extent that laser ablation may allow maintenance of structural integrity while altering the surface geometry in such a way as to promote ingrowth of new bone, this experimental model represents an advance in understanding how osteogenesis in cortical bone grafts might be improved.

Stress transients are generated in polyimide by irradiation with excimer‐laser pulses at radiant exposures between 3×10−3 and 102 J/cm2. The duration and peak stress of these transients are measured using piezoelectric film transducers. For all the wavelengths tested (193, 248, 308, 351 nm) we determine three ranges of radiant exposure within which different physical mechanisms govern the stress generation. The scaling of stress with radiant exposure depends on wavelength only in the low fluence regime. In this regime the stresses observed are attributed to subsurface thermal decomposition at 351 and 308 nm and to photodecomposition at 248 and 193 nm. At higher radiant exposure the stress generation is governed either by the thermal expansion of the gaseous ablation products or by the formation and expansion of a dense plasma. The boundary between these two regimes is identified from the variation of the mechanical coupling coefficient with radiant exposure. The results also indicate that heat conduction contributes significantly to the coupling of energy into the target, leading to a reduction in the stresses generated and to an increase in etch depth when ablation is achieved.