Note: benign and reproducible preparation of titanium tips.

Fabrication of titanium tips via electrochemical etching is commonly hindered by the formation of a tough oxide layer. A new one-step approach based on dc etching in a non-aqueous electrolyte is presented. The electrochemical tip etching was carried out at 20 V in a benign etchant of 1M NaCl in ethylene glycol. Tip radii below 100 nm are demonstrated using current cut-off control and approaching 150 nm without cut-off control. The simplicity and efficiency of the approach eliminates pre and post electropolishing steps due to the electropolishing capability of a NaCl-ethylene glycol based electrolyte.

Note: electrochemical etching of silver tips in concentrated sulfuric acid.

Sharp metal tips have many uses, including in scanning probe microscopy. Silver is a particularly interesting metal for plasmonic enhancement, e.g., in tip-enhanced Raman spectroscopy, however few methods for the production of silver tips have been explored. A simple and reliable one step dc electrochemical method for the production of sharp silver tips in concentrated H2SO4 is presented. The optimal conditions are 10 V cell voltage and 99% sulfuric acid for tip radii below 100 nm. A LabView program was written to control the cut-off of the circuit to within a millisecond to avoid blunting the tips after drop-off.

The effect of GaAs(100) surface preparation on the growth of nanowires.

The influence of GaAs(100) substrate surface preparation on Au-catalysed GaAs nanowires was studied. Elongated pits of varying dimensions and orientation were formed on GaAs(100) substrates depending on the interaction with Au and surface oxides. The resulting surface topography is shown to influence the density and orientation of nanowires. [111] B-oriented nanowires nucleated from Au particles lying on the sidewall facets of the pits, while [011]-oriented nanowires nucleated from Au particles lying outside the pits.

Recrystallization of tungsten wire for fabrication of sharp and stable nanoprobe and field-emitter tips.

Atomically sharp tungsten tips made from single crystal tungsten wire are superior to those made from cold-drawn polycrystalline wire but are rarely used due to their high price. We have devised a method of obtaining highly crystalline tungsten wire by recrystallizing cold-drawn wire. The effect of various heat treatments on the wire microstructure was observed using scanning electron microscopy and x-ray diffraction. A dramatic difference in the shapes of tips etched from cold-drawn and recrystallized wires was observed using transmission electron microscopy. The described annealing process is an inexpensive alternative to using single crystal wires.

[Cystoid macular edema in a pseudophakic patient after several glaucoma procedures. Is local therapy with bimatoprost the reason?]. / Zystoides Makulaödem bei Pseudophakie nach mehreren drucksenkenden Eingriffen. Ist die lokale Medikation von Bimatoprost die Ursache?

BACKGROUND: Prostaglandin-like drugs such as latanoprost (Xalatan), travoprost (Travatan) and bimatoprost (Lumigan) lower the intraocular pressure by improving the outflow of aqueous humor via the uveoscleral pathway. Up to now there is no report about a macular edema after the topical use of Lumigan eye drops in a pseudophakic patient with an intact posterior capsule. PATIENT: A 69-year-old pseudophakic patient with a 14-year history of glaucoma in pseudoexfoliation syndrome, revealed a cystoid macular edema after local treatment with bimatoprost . 6 months earlier a phakoemulsification followed by the insertion of a posterior intraocular lens was performed on the left eye. Due to an elevated intraocular pressure after the surgery, which could not be controlled either by several eyedrops, or by three more operations (one viscocanalostomy with mitomycin c, two cyclophotocoagulations), therefore, a final attempt with bimatoprost (Lumigan) was started. Two weeks later the patient complained of blurred vision, caused by a cystoid macular edema. RESULTS: After discontinuation of bimatoprost and initiation of a local and systemic anti-inflammatory therapy, the edema resolved and visual acuity recovered. CONCLUSION: Bimatoprost (Lumigan) , a synthetic prostamid is similar to human prostaglandins, especially to prostaglandin F (2alpha.) Although it does not bind to the same receptor, its side effects are comparable to those of common prostaglandin analogues. So far there are no reports about the manifestation of a macular edema after using bimatoprost in pseudophakic eyes with an intact posterior capsule. Even if three more operations followed the cataract surgery, we suspect that bimatoprost eyedrops can be held responsible for this. Therefore they should be used with great care and in clear indications, particularly in pseudophakic patients.

Determination of the mean inner potential in III-V semiconductors, Si and Ge by density functional theory and electron holography.

The mean inner potentials of various III-V semiconductors, Si and Ge have been calculated by density functional theory methods. For that purpose, the Coulomb potential of slabs consisting of a crystal and vacuum region has been computed and averaged inside the crystal region. The computed values are in agreement with experimental values obtained by electron holography for Si and GaAs. For the other semiconductors, the deviations are smaller than 0.8 V. The results from density functional theory are approximately 10% smaller than the values derived from atomic scattering factors computed by Hartree Fock calculations.

Characterization of microbial particle release from biomass and building material surfaces for inhalation exposure risk assessment.

A conceptual approach including measurements of materials at rest (step 1), measurements using a large rotating drum (step 2) or a Particle-FLEC (step 2) and measurements at a workplace (step 4) has been used to characterize the release of microbial components (bacteria, fungi, actinomycetes, endotoxin or enzymes) and particles from straw, wood chips or fungal cultures of different ages on gypsum boards. Repeated agitation or handling periods were included in step 2 and step 4. There was a low similarity between the amount of microbial components measured in step 1 and the aerosolized amount (step 2) from gypsum boards, wood chips and straw. Ratios between some microbial components measured at the workplace (step 4) and measured in step 2, showed similarities. Less than 1.3% of the total amount of microorganisms and endotoxin becomes airborne during 5 min of agitation of straw or wood chips. Most microbial components were released at higher rates during the first agitation period than during the following periods. However, differences were seen between different microbial components, and endotoxin from straw was released at the same rate in two successive agitation periods. Fungal particles smaller than spores were released from fungal colonized gypsum boards at amounts that were up to 30 times higher in the first agitation period compared with that in the following period, while fungal spores were released at amounts that were five times as high in the first period compared with that in the following period. In addition to differences between microbial components, the release patterns of microbial components were different for wood chips and straw. The time for maximum particle release to half particle release was longer for straw than for wood chips. The observation that some components, e.g. endotoxin, are released at the same rate in two successive handling steps, and that others (e.g. fungi) are mainly released initially, shows that the exposure period to different components from the same material differs in duration. The observed differences in the release patterns of different components and the differences between materials are important when preventive steps are to be taken, and it stresses the importance of applying a relevant sampling time and period in exposure assessments.

Determination of fungal spore release from wet building materials.

The release and transport of fungal spores from water-damaged building materials is a key factor for understanding the exposure to particles of fungal origin as a possible cause of adverse health effects associated to growth of fungi indoors. In this study, the release of spores from nine species of typical indoor fungi has been measured under controlled conditions. The fungi were cultivated for a period of 4-6 weeks on sterilized wet wallpapered gypsum boards at a relative humidity (RH) of approximately 97%. A specially designed small chamber (P-FLEC) was placed on the gypsum board. The release of fungal spores was induced by well-defined jets of air impacting from rotating nozzles. The spores and other particles released from the surface were transported by the air flowing from the chamber through a top outlet to a particle counter and sizer. For two of the fungi (Penicillium chrysogenum and Trichoderma harzianum), the number of spores produced on the gypsum board and subsequently released was quantified. Also the relationship between air velocities from 0.3 to 3 m/s over the surface and spore release has been measured. The method was found to give very reproducible results for each fungal isolate, whereas the spore release is very different for different fungi under identical conditions. Also, the relationship between air velocity and spore release depends on the fungus. For some fungi a significant number of particles smaller than the spore size were released. The method applied in the study may also be useful for field studies and for generation of spores for exposure studies.

Determination of the mean inner potential in III-V semiconductors by electron holography.

The mean inner potential of GaAs(14.18V), InAs(14.50V), GaP(14.35V) and InP(14.50V) has been measured by transmission electron holography using the phase shift of the (000)-beam of the first hologram sideband. To provide a defined specimen geometry we used 90 degrees wedges obtained by the cleavage technique. The exact excitation condition as well as the acceleration voltage of the electrons were determined from convergent beam electron diffraction images. The magnification is extracted from two-beam lattice fringe images and dynamical effects are taken into account by Bloch-wave calculations.

Minor role of oxidative stress during intermediate phase of acute pancreatitis in rats.

Reactive oxygen species have been implicated in the pathogenesis of acute pancreatitis. Few studies have focused on the loss of endogenous antioxidants and molecular oxidative damage. Two acute pancreatitis models in rats; taurocholate (3% intraductal infusion) and cerulein (10 microg/kg/h), were used to study markers of oxidative stress: Glutathione, ascorbic acid, and their oxidized forms (glutathione disulfide and dehydroascorbic acid), malondialdehyde, and 4-hydroxynoneal in plasma and pancreas, as well as 7-hydro-8-oxo-2'-deoxyguanosine in pancreas. In both models, pancreatic glutathione depleted by 36-46% and pancreatic ascorbic acid depleted by 36-40% (p <.05). In the taurocholate model, plasma glutathione was depleted by 34% (p <.05), but there were no significant changes in plasma ascorbic acid or in plasma and pancreas dehydroascorbic acid, malondialdehyde, and 4-hydroxynoneal, and no significant changes in the pancreas glutathione disulfide/glutathione ratio. While pancreas glutathione disulfide/glutathione ratio increased in the cerulein model, there were no significant changes in plasma glutathione, plasma, or pancreas ascorbic acid, dehydroascorbic acid, 4-hydroxynoneal, and malondialdehyde, or in pancreas 7-hydro-8-oxo-2'-deoxyguanosine. Reactive oxygen species have a minor role in the intermediate stages of pancreatitis models.

Anomalous mobility of strongly bound surface species: Cl on GaAs(001)-c(8 x 2)

Although strongly bound chemisorbates at low coverage readily diffuse on metal surfaces at 300 K, they generally do not diffuse on semiconductor surfaces because of a large corrugation in the adsorbate-surface interaction potential. Chlorine chemisorbed on the Ga-rich GaAs(001)-c(8x2) surface has anomalously fast diffusion even though the chemisorption state is tightly bound and highly specific. Simple Hartree-Fock total energy calculations suggest that this diffusion of strongly bound adsorbates can occur at 300 K because there are multiple nearly degenerate adsorbate sites.

[The military pharmocopoeias in Denmark]. / De danske militaerfarmakopeer.

In 1812, the Danish king decided to reform the medicine supply to the military on the initiative of the pharmacist Jens Peter Groth (1785-1832), the tenant of the Royal Orphanage Pharmacy in Copenhagen. Up till then, the military physicians themselves for fixed medicine money had supplied the army and the navy with the necessary medicine, but now it was decided that Groth should establish a military pharmacy to manage the future medicine supply to the army and the navy in Copenhagen and also that the medicial members of the General Direction of the Military Medical Service should compile a military pharmacopoeia for both of the fighting services. The Royal Orphanage Pharmacy was named the Royal Military & Orphanage Pharmacy and the ordered military pharmacopoeia was issued in 1813. Compared with the national pharmacopoeia, the military pharmacopoeia was characterized by a limitation of the number of medicaments and by a simplification of the compositions. These facts were caused by the economic considerations and the duty of the military physicians themselves to prepare the simple medicaments. The subsequent editions of the military pharmacopoeia were published in 1840, 1857 og 1869, but in 1874, the military pharmacopoeia was cancelled, because the medicaments in the military pharmacopoeia were less effectual and less palatable than the medicaments in the national pharmacopoeia, and because the use of the military pharmacopoeia did not result in economic savings.

Proteases and protease inhibitors in cerulein-induced acute pancreatitis in rats.

BACKGROUND: Proteases and protease inhibitors are important in acute pancreatitis (AP), although little is known about the time course in cerulein-induced AP in the rat. MATERIALS AND METHODS: AP was induced by supramaximal stimulation of cerulein, 10 microgram/kg/h, and during 72 h we measured lipase, amylase, albumin, prekallikrein, factor X, alpha(1)-protease inhibitor, alpha(1)-macroglobulin, alpha(2)-antiplasmin, antithrombin III (all in plasma) and macroscopic and histologic variables. RESULTS: Within 12 h an edematous pancreatitis was evident with peak values of peritoneal exudate, pancreatic wet weight ratio, and plasma amylase and lipase activities. Histologically, edema and vacuolization were prominent already after 3 and 6 h, respectively, while inflammation, necrosis, and total histological score gradually increase to reach peak levels at 48 h. Proenzymes and most plasma protease inhibitors decreased to low levels after 6-12 h followed by a gradual increase. The sequential changes over time indicate that kallikrein - kinin activation, and plasminogen activation are probably early events in cerulein-induced AP in rats. alpha(1)-Macroglobulin and alpha(1)-protease inhibitor gradually decreased during the whole study period, probably being "second line" defense inhibitors. Levels above normal were seen for alpha(2)-antiplasmin and factor X at 48 h, normalizing at 72 h. CONCLUSIONS: These results suggest that protease activation and protease inhibitor consumption occur in cerulein-induced AP in the rat.

Proteases and protease inhibitors in taurocholate-induced acute pancreatitis in rats.

CONCLUSION: Taurocholate-induced acute pancreatitis (AP) in the rat mimics early necrotizing human pancreatitis. Protease activation and protease inhibitor consumption occur consistent with a two-stage development, and contact-phase activation is a possible primary event in this model. BACKGROUND: Proteases and protease inhibitors have been indicated to play an important role in both human and experimental acute pancreatitis, although little is known about them in rats. METHODS: Three percent sodium taurocholate was infused into the bilio-pancreatic duct to induce AP, and over 0-72 h we measured lipase, amylase, albumin, prekallikrein, factor X, alpha-1-macroglobulin, alpha-2-antiplasmin, antithrombin III, alpha-1-protease inhibitor, and C1-esterase inhibitor (all in plasma) and histologic and macroscopic findings. RESULTS: A severe necrotizing, nonlethal, AP was induced with an early increase in plasma lipase and alpha-amylase activity levels and peritoneal exudate followed by a return to near control levels after 72 h. Histologic score and pancreatic wet weight ratio increased initially and remained high during the observation period. The protease inhibitors C1-esterase inhibitor, alpha-2-antiplasmin, and antithrombin III decreased early, within 0-6 h, whereafter levels normalized. The protease inhibitors alpha-1-macroglobulin and alpha-1-protease inhibitor later gradually decreased over the 72 h.

Physicians' abdominal auscultation. A multi-rater agreement study.

BACKGROUND: Abdominal auscultation has an important position in the physical examination of the abdomen. Little is known about rater agreement. The aim of this study was to describe rater agreement and thus, indirectly, the value of the examination. METHODS: In a semi-virtual setup 12 recordings of the intestinal sounds from 8 patients with acute abdominal pain and 4 healthy volunteers were presented to 100 physicians. The physicians were asked to characterize the intestinal sounds as normal or pathologic. Fisher's exact test was used for comparison between groups of physicians. RESULTS: Overall, 72% of the answers with regard to healthy volunteers concluded that the sounds were normal (equalling agreement), whereas 64% of answers with regard to intestinal obstruction concluded that the sounds were pathologic (but agreement was higher due to agreement on wrong diagnosis in one case). Bowel sounds from colonic obstruction were diagnosed as pathologic in 94 of 100 answers. In peritonitis disagreement dominated. Specialists in gastrointestinal medicine diagnosed bowel obstruction significantly more poorly than non-specialists in gastrointestinal surgery (P < 0.05). CONCLUSION: Rater agreement in normal subjects and in patients with intestinal obstruction was acceptable for a clinical examination. Abdominal auscultation is a helpful clinical examination in patients with acute abdominal pain.

Frontal gamma-band enhancement during multistable visual perception.

The aim of our study was to find out whether an increase in the gamma band may be related to the reversal phase during viewing of an ambiguous pattern. The present study describes the significant gamma band (30-50 Hz) activity increase in EEG during states of perceptual switching (reversal state). In our experiments the multistability was induced with an ambiguous stimulus pattern, known as stroboscopic alternative motion (SAM). The investigations carried out in 11 subjects included a measuring strategy with three different experimental conditions: (1) recording of spontaneous EEG as baseline; (2) recording of the EEG during naive observation of the ambiguous pattern; (3) recording of EEG during active observation of SAM. The results indicate that the multistable perception is one of the multifold cognitive processes giving rise to 40 Hz enhancement in the entire cortex. The most significant 40 Hz enhancements were measured in frontal areas and can reach increases of 40 to 50% in states of naive and active observations of SAM, respectively, in comparison to spontaneous EEG recordings. The results indicate that the increase of frontal gamma band is related to the destabilization of the perceptual system when viewing multistable patterns.

Continuous phase transitions in the perception of multistable visual patterns.

The phenomenon of stroboscopic alternative motion exhibits five different percepts that are seen with an increase in the frequency of presentation: (a) succession, (b) fluttering motion, (c) reversible clockwise and counter-clockwise turning motion, (d) oppositional motion and (e) simultaneity. From a synergetic point of view the increase in frequency is a control parameter and the different percepts are order parameters with phase transitions in between. The neural network model of Carmesin and Arndt is applied to receive predictions about hysteresis and phase transitions between these order parameters. Empirical data show the different motion percepts (b), (c) and (e) have lognormal distributions. Following the theoretical model, it is argued that there are three different phases, (a), (c) and (e), with two continuous phase transitions, (b) and (d), between them. The experimental data substantially match the theoretical assumptions.

Carbon dioxide transport in rats with acute pancreatitis.

CONCLUSION: The production, release, and transport of carbon dioxide from tissues to blood are facilitated both systemically and in the gastrointestinal tract in acute pancreatitis. Red blood cells are responsible for the major exchange and transport of this increase in CO2. The existence of arteriovenous shunting within the intestine is associated with tissue ischemia, which may be involved in the etiology of gut barrier failure in acute pancreatitis. BACKGROUND: Hemodynamic alterations in acute pancreatitis have been described, while little is known about CO2 metabolism. METHODS: Carbon dioxide metabolism was evaluated by virtual values of venoarterial CO2 concentration differences in the early phase after sham operation or induction of acute pancreatitis by intraductal injection of 5% sodium taurocholate in rats. RESULTS: In acute pancreatitis, virtual values of the CO2 concentration increased in arterial RBC at 6 and 12 h as well as in caval and portal vein RBC and plasma. Virtual values of the dissolved CO2 concentration were reduced in arterial and portal vein blood. The increment in blood CO2 concentration related to the increase in CO2 tension from arterial to caval or portal vein valves at constant CO2 tension. The total increment in CO2 concentration from arterial to caval or portal vein blood increased. Whole body oxygen extraction increased, whereas gut oxygen extraction decreased in pancreatitis.