Stamp Method Research Articles

Minocycline and staphylococcal microbiota in acne patients

Minocycline is the tetracycline antibiotic used in the therapy of different forms of acne vulgaris. It was shown previously that S. aureus may play a role of causative agent in inflammatory acne. This study was performed aiming to estimate sensitivity of staphylococcal strains from acne patients towards minocycline. Group of acne 29 patients 17-31 years old with different severity grades was compared with control group of 22 volunteers of the same age. Staphylococcal microflora was obtained from face skin use the stamp method and identified by standard scheme. Sensitivity of strains to minocycline was estimated by microdilution method in DMEM medium. In both groups 5 species of staphylococci were found: S. aureus, S. epidermidis, S. haemolyticus, S. intermedius, S. saprophyticus. At that we established that S. aureus was the main species in acne group I (62%) as well as in control group (38%). From all species studied the S. epidermidis was found to be most sensitive to minocycline with median of the minimal inhibiting concentration equaling 4 µg/ml, and most resistant was S. saprophyticus – with MIC of 16 µg/ml. Sensitivity of strains of S. aureus to minocycline was higher in acne group than in controls: 39% of acne group isolates had MIC of 4 µg/ml, although 63% of control group isolates had MIC of 8 µg/ml.

Model membrane-mediated cell alignment through surface hydrophobicity

ABSTRACTWe show a realization of well-controlled alignments of human lung fibroblast cell parallel to the guided direction achieved by selectively patterned model membranes. The supported lipid bilayer membranes (SLBMs)-mediated cell alignment and selective growth in particular un- derlying surface properties were achieved through peeling-off of the polydimethylsiloxane (PDMS) stamp. We used the PDMS not only as a microfluidic channel to reconstruct model membrane on a hydrophilic surface, but also as a self-inking stamp for the substrate-surface modification by transfer of outmost low-molecular weight PDMS oligomers (S-PDMS). We found that surface hydrophobicity of solid supports is controlled by thermally-assisted stamping methods and this is crucial for the cell adhesion in lipid-free regions.

Microfluidic Stamping on Sheath Flow.

A microfluidic stamping method to form functional shapes on a cross section in fiber-shaped flow is proposed. Microfluidic stamping and overstamping allow various cross sectional shapes on the 3D flow. The shapes can be controlled by a change in combination of structures and fluidic conditions which correspond to stamp type and stamping force.

Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface.

ABSTRACTShark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface.

‘Accident investigation in the wild’ – A small-scale, field-based evaluation of the STAMP method for accident analysis

Little information is currently available about the application of systemic accident analysis methods by practitioners and whether their analysis needs are met. This study provides an insight into this issue by obtaining a practitioner evaluation of STAMP and understanding how the method’s usage characteristics affect its use in a live investigation scenario. Six participants took part in a workshop to analyse data collected during a (high-fidelity, partly field-based) simulated investigation exercise using STAMP. The analysis outputs were assessed, along with the participants’ questionnaire and focus group responses pertaining to their experiences of using the method. When combining the mixed methods data generated during the study, a number of observations regarding the participants’ experiences of using STAMP were made. However, improving the method’s usability and graphical output were highlighted as key developments that may improve its acceptance by practitioners.

Direct Patterning of Self‐Assembled Monolayers by Stamp Printing Method and Applications in High Performance Organic Field‐Effect Transistors and Complementary Inverters

Self‐assembled monolayer (SAM) is usually applied to tune the interface between dielectric and active layer of organic field‐effect transistors (OFETs) and other organic electronics, a time‐saving, direct patterning approach of depositing well‐ordered SAMs is highly desired. Here, a new direct patterning method of SAMs by stamp printing or roller printing with special designed stamps is introduced. The chemical structures of the paraffin hydrocarbon molecules and the tail groups of SAMs have allowed to use their attractive van der Waals force for the direct patterning of SAMs. Different SAMs including alkyl and fluoroalkyl silanes or phosphonic acids are used to stamp onto different dielectric surfaces and are characterized by water contact angle, atomic force microscopy, X‐ray diffraction, and attenuated total reflectance Fourier transform infrared. The p‐type dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (DNTT) and n‐type F16CuPc OFETs show competitive mobility as high as 3 and 0.018 cm2 V−1 s−1, respectively. This stamp printing method also allows to deposit different SAMs on certain regions of same substrate, and the complementary inverter consists of both p‐type and n‐type transistors whose threshold voltages are tuned by stamp printing SAMs and shows a gain higher than 100. The proposed stamp or roller printing method can significantly reduce the deposition time and compatible with the roll‐to‐roll fabrication.

Hybrid quenching method of hot stamping for automotive tubular beams

Recently, tubular-type coupled torsion beam axle, which is a component of the automotive rear suspension systems, has been developed by using ultra-high strength steel. It is manufactured by hot stamping process to enhance the strength and reduce springback. The hot stamping process is classified as a direct method and an indirect method according to forming sequence and quenching method, so-called die quenching or water quenching. Each of these methods has limitations in the aspect of dimensional accuracy and strength. Hybrid quenching is a new quenching method which sprays water to the tube directly in addition to die quenching. In this study, direct hot stamping with hybrid quenching was applied to produce an automotive tubular coupled torsion beam axle of ultra-high strength steel. This study proposes a simulation method of hybrid quenching for tubular beam and the hybrid quenching method was evaluated experimentally. Finally, the proposed hybrid quenching method has been found very effective in reducing the cooling time and thermal deformation.

DEVELOPMENT AND RESEARCH OF A NEW METHOD OF STAMPING

The article describes the results of theoretical and experimental studies of a new method of stamping with regulated heating of workpiece to a predetermined temperature and its subsequent deformation by bilateral exposure of combustion products of gas mixtures. The authors demonstrated the possibility of heating the formed preform directly into the die cavity until the hot working temperature range. At this time, heating of the billet is less than 1 s, and the pressure of the combustible gas mixture depending on the material and thickness of the preform is 0.5 ... 2.0 MPa. The dependences of the parameters are determined for the calculation of the stamping process. Experimental studies have shown that this method by heating the workpiece creates favorable conditions for its deformation. This provides stamping parts with complex shapes in a single technological transition, using relatively simple die tooling, signifi cantly reduces the cost of the stamped parts. Due to this and the low cost of the used equipment, this method of stamping can fi nd effective application in industrial production.

Comparative Analysis of Several Transmission Pricing Methods

This paper analyses several common transmission pricing methods of marginal cost and embedded cost deeply. It analyses pricing models of several transmission pricing methods, long-run marginal cost (LRMC) method, MW-Mile method, sensitivity method, flow tracing method, contract path method and stamp method. It also gives a comprehensive comparison of characteristics and limitations of these pricing methods, discusses their applicable conditions in aspects of fairness, economic, financial balance, transparency, operability and others, and makes a quantitative research of comparison based on a case, and verifies the results.

Design of Press Tools to Investigate the Hot Stamping Behaviour of Alternative Coatings for Press-Hardened Steel Parts

Due to oxidation and decarburization during heat treatment prior to hot stamping, various coating products have been developed in the last decades. Press-Hardened Steel (PHS) components for passenger cars are generally coated by aluminized or galvanized (GI) coatings. The aluminized coating presents a good formability at high temperature and permits forming and quenching components in the same press tools with a so called direct hot stamping method. Due to a strong cracking in the base material during direct hot stamping induced by liquid-metal embrittlement (LME), galvanized coated products must be pre-formed at low temperature and undergo heat treatment in separate press units. Moreover, the oxide scale formed on GI parts must be removed by abrasive blasting, whereas aluminized parts can be directly painted after hot forming. However, higher performance in corrosion resistance has been observed for galvanized parts, in particular in cosmetic and cut-edge corrosion. This increase is linked to the sacrificial effect or cathodic protection provided by the layer containing zinc. Daimler AG is investigating the possibility of improving performance of PHS body parts in terms of suitability for direct hot stamping and corrosion protection by developing new coating materials. In the following article, the main particularities and challenges involved in both current coating products will be introduced. The development of specific press tools for this study, as well as the corresponding simulation of hot forming will be presented. Finally, the hot forming behaviour and anticorrosive properties of both current products will be presented.

Study of Different Large Bodies Manufacturing Based on Combined Methods of Deformation

Metallurgy and heavy engineering construction, which are considered the most energy-intensive industries, place great focus on complex shaped thick-gage plate metal items of equipment with the wall thickness exceeding 40 mm and the diameter /width of up to 5000 mm. Such items of equipment include large machine parts manufactured by means of hot plate stamping, like bodies of rotation (for example, the segment of the radial surface of converter shell, the bottom part of degassing unit, etc.) utilized as pressure-operated devices, vessels, tanks and other facilities by metallurgical, petrochemical, oil and gas, and nuclear industries. Presently known manufacturing methods of such items of equipment, for example hot stamping methods, have a number of technological problems. The proposed work is aimed at the development of innovative power-efficient, high performance methods of obtaining complex shaped large size items. The scientific novelty of the task lies within the creation and development of the theory and technology of the new methods of deformation based on the combination of the plate rolling and stamping processes as well as the combination of asymmetric rolling and plastic bending processes. Casings on two converters were produced and installed in the oxygen-converter plant. Economic effect from the installation of the developed technology based only on the combination of asymmetric rolling and plastic bending processes was more than 1 million dollars.

Verification of Tin Car Body Production by Unconventional Stamping Method

The contribution deals with verification of tin car body production using single action experimental stamping die. Two methods of car body production were verified - the first one used open die made of tool steel and the second one used closed die made of tool steel with Fibroflex at the bottom of the die. The tin steel sheet TS 245 with thickness 0.28 mm had been used for the car body production. The shapes of pressings were evaluated using the photogrammetric 3D measuring system ARGUS. The ARGUS optical system allowed evaluating the wall thickness change and the deformation on the surface of pressings as well. These values had been compared for both method of the tin car body production.

A new process of forming metallic bipolar plates for PEM fuel cell with pin-type pattern

Bipolar plates are the most important and expensive components of a fuel cell. These plates can be fabricated by different processes, such as machining graphite plates, producing composite materials, and forming metallic sheets. Due to some benefits of the metallic plates, especially with stainless steel sheets, they have recently been more noticeable. There are various flow field patterns with different applications in these plates, being classified into simple and complex ones in forming process for spiral or parallel and multi-array pin-type examples, respectively. In this study, hydroforming, stamping, and hybrid hydroforming–stamping methods have been used to investigate the forming capability of multi-array pin-type pattern, and, consequently, to compare the results of filling percentage and thickness distribution of these methods. According to the results, samples formed by the hybrid method have shown desirable filling percentage and thickness distribution. The effect of preload pressure of this method on thickness distribution has subsequently been studied and it was observed that the thickness distribution of the formed sample was enhanced by maximizing the pressure of the hydroforming stage.

Visualization of hospital cleanliness in three Japanese hospitals with a tendency toward long-term care

BackgroundHospital cleanliness in hospitals with a tendency toward long-term care in Japan remains unevaluated. We therefore visualized hospital cleanliness in Japan over a 2-month period by two distinct popular methods: ATP bioluminescence (ATP method) and the standard stamp agar method (stamp method).MethodsThe surfaces of 752 sites within nurse and patient areas in three hospitals located in a central area of Sapporo, Japan were evaluated by the ATP and stamp methods, and each surface was sampled 8 times in 2 months. These areas were located in different ward units (Internal Medicine, Surgery, and Obstetrics and Gynecology). Detection limits for the ATP and stamp methods were determined by spike experiments with a diluted bacterial solution and a wipe test on student tables not in use during winter vacation, respectively. Values were expressed as the fold change over the detection limit, and a sample with a value higher than the detection limit by either method was defined as positive.ResultsThe detection limits were determined to be 127 relative light units (RLU) per 100 cm2 for the ATP method and 5.3 colony-forming units (CFU) per 10 cm2 for the stamp method. The positive frequency of the ATP and stamp methods was 59.8% (450/752) and 47.7% (359/752), respectively, although no significant difference in the positive frequency among the hospitals was seen. Both methods revealed the presence of a wide range of organic contamination spread via hand touching, including microbial contamination, with a preponderance on the entrance floor and in patient rooms. Interestingly, the data of both methods indicated considerable variability regardless of daily visual assessment with usual wiping, and positive surfaces were irregularly seen. Nurse areas were relatively cleaner than patient areas. Finally, there was no significant correlation between the number of patients or medical personnel in the hospital and organic or microbiological contamination.ConclusionsOngoing daily hospital cleanliness is not sufficient in Japanese hospitals with a tendency toward long-term care.

Fabrication of Silver Interdigitated Electrode by a Stamp Method

A stamp method was developed in this study to fabricate interdigitated electrodes (IDEs) on glass substrate from a 37.5 wt% silver ink. This method is simple and fast. A small amount of silver ink was first dripped into an IDE-patterned sponge of a stamp and then one could stamp out the desired IDE pattern made of nanosized silver colloids on a glass substrate, which was subsequently sintered at 280°C for 10 minutes to obtain the final silver IDE. Our brief study showed that when a large stamping force was used, more ink would be stamped out in the beginning and it decreased after each usage. However, if the force was too small, there would not be sufficient ink for a complete IDE. There existed therefore an optimal force to fabricate IDEs with minimal changes from sample to sample. The average dimension of an IDE when the applied force was 102 gm was roughly 403 ± 20 µm in width and 1154 ± 153 nm in height, and the average final electrical resistivity was about10×10-6 Ω-cm.

India's New Cost Allocation Method for Inter-State Transmission: Implications for the Future of the Indian Electricity Sector

This article describes the evolution of cost allocation for India's inter-state transmission system and examines the impacts of the shift from a regional postage stamp method to a flow-based cost allocation charging method. Less congestion and losses will likely ensue as generators and distribution entities respond to prices that more precisely reflect their use of the system.

A preregistered STAMP method for image-guided temporal bone surgery

Image-guided otological surgeries require minimal invasiveness and high accuracy, and these two factors usually compete with each other. Our recently developed registration method, called the STAMP method, showed minimal invasiveness with accuracy comparable to that of the current more invasive registration methods used in image-guided temporal bone surgery. However, surgeons perceived the STAMP method as complex and time-consuming. We modified our STAMP method to further simplify the surgeon's tasks in the operating room. We attached an optical tracking target on the STAMP plate and registered the plate in an IGS system before surgery, outside the operating room. The registration was completed in the operating room by finishing the final simple task, which was to hold the preregistered STAMP plate still on the patient's temporal bone. We tested this modified preregistered STAMP method in simulation surgery and actual surgeries. The registration times and errors of the STAMP method and preregistered STAMP method were compared. The proposed new preregistered STAMP method significantly reduced the registration time in the operating room without compromising the registration accuracy. The preregistered STAMP method significantly improved the original STAMP method in terms of time and convenience. It is now considered to be one of the easiest and quickest registrations for image-guided temporal bone surgery. Because most of the critical processes of registration can be completed in the laboratory, the registration task in the operating room is therefore greatly simplified, thus allowing surgeons to concentrate more on the surgery itself.

Low Loss Polymer Optical Waveguide Replicated from Flexible Film Stamp Made of Polymeric Material

This paper describes a flexible stamping method, which employs a flexible film stamp made of polymeric materials. Unlike conventional hard stamps, the flexible film stamp does not require either the stamp or its substrate to be perfectly flat, which means large area stamping is easy to achieve at reduced cost. We confirmed this by replicating 50 µm square multi-mode optical polymer waveguides. The propagation loss of the waveguide is only 0.06 dB/cm at a wavelength of 850 nm, which satisfies the basic requirement for optical circuit boards, and the waveguide was used to fabricate a flexible optical circuit board with mechanically transferable (MT) connectors.

Possibility of the Increase in Titanium Sheets' Drawability

Forming of titanium sheets, especially titanium alloy sheets, is very difficult due to low drawability caused by a high ratio of the yield point to the tensile strength Re/Rm, usually more than 90%. Although drawability of titanium sheets can be enhanced by forming at elevated temperatures it is avoided due to the high costs and difficulties associated with the operation of the process. Therefore the authors have developed an unconventional stamping method allowing for forming of almost unworkable materials at ambient temperature, such as Ti6Al4V titanium alloy. The paper presents both numerical simulation and experimental results of the stamping process using a device specially designed for this purpose.

Fabrication of Bipolar Plates Based on Graphite Sheet via Stamping Method

In this paper, graphite sheet (or exfoliated/expanded graphite) was used as material for bipolar plates in DMFC. These were substituted to graphite bipolar plates adopted in commercialized DMFC and their performances were characterized in order to identify its feasibility of commercialization. The results showed that there is little difference of performances between graphite and graphite sheet bipolar plates, while this difference became larger with increasing number of cells in stack. It is speculated that higher ohmic resistance of graphite sheet than that of graphite and its flexibility which affected ribs of flow channels to compress GDL excessively accounted for worse performances of DMFC with a number of cells. Finally, this bipolar plate can reduce 22 % of weight compared to graphite and cost under $ 2 per a sheet, which makes it attractive to bipolar plates for DMFC.