The Influence of a Second Ground Electrode on Hydrogen Peroxide Production from an Argon Plasma Jet and Correlation to Antibacterial Efficacy and Mammalian Cell Cytotoxicity

This study investigates how addition of a second ground electrode in an argon plasma jet influences the production of hydrogen peroxide (H2O2) in deionised water (DIW). Briefly, plasma is ignited by purging argon gas through a quartz tube at 1 litre per minute and applying a sinusoidal voltage of 7 kV (peak-peak) at 23.5 kHz to a high voltage stainless steel needle electrode sealed inside the quartz tube surrounded by single or double copper ring(s) situated downstream of the high voltage electrode that served as the ground electrode(s). The mechanisms of H2O2 production are investigated through the electrical and optical plasma properties and chemical analysis of the treated DIW. We discover that the addition of a second ground electrode results in higher accumulation of charges on the wall of quartz tube of the plasma jet assembly resulting in an increase in the discharge current and dissipated power. This further leads to an increase in the electron temperature that more than doubles the H2O2 production through dissociative recombination of water vapour molecules, whilst still maintaining a biological tissue tolerable gas temperature. The double ground electrode plasma jet is shown to be highly effective at reducing the growth of common wound pathogens (Pseudomonas aeruginosa and Staphylococcus aureus) in both planktonic and biofilm states whilst inducing a low level of cytotoxicity in HaCaT keratinocyte skin-like cells under certain conditions. The information provided in this study is useful in understanding the complex physicochemical processes that influence H2O2 production in plasma jets, which is needed to optimise the development of plasma sources for clinical applications.

Carbon Microstructures Synthesis in Low Temperature Plasma Generated by Microdischarges

The aim of this paper is to investigate the process of growth of different carbon deposits in low-current electrical microdischarges in argon with an admixture of cyclohexane as the carbon feedstock. The method of synthesis of carbon structures is based on the decomposition of hydrocarbons in low-temperature plasma generated by an electrical discharge in gas at atmospheric pressure. The following various types of microdischarges generated at this pressure were tested for both polarities of supply voltage with regard to their applications to different carbon deposit synthesis: Townsend discharge, pre-breakdown streamers, breakdown streamers and glow discharge. In these investigations the discharge was generated between a stainless-steel needle and a plate made of a nickel alloy, by electrode distances varying between 1 and 15 mm. The effect of distance between the electrodes, discharge current and hydrocarbon concentration on the obtained carbon structures was investigated. Carbon nanowalls and carbon microfibers were obtained in these discharges.

The treatment of microbubble disease of 20th century cellulose acetate microfilm: application of ethyl cellulose and microrepair method

Microbubble disease observed in cellulose acetate microfilm is accompanied by the production of vinegar syndrome, which affects the image integrity. In the present study, samples of cellulose acetate microfilm with microbubble disease were selected to investigate potential treatment methods. Samples were sourced from the Republic of China (AD 1912–1949) microfilm collections held in the Second Historical Archives of China. A combination of optical microscopy and a stainless-steel needle was used to remove plasticizer exudation within microbubbles. The plasticizer was effectively removed by infiltrating butan-1-ol into the microbubble from a small hole made by the stainless-steel needle. SEM and confocal microscopy were used to study the morphology and roughness of the internal surface of the microbubbles. It was found that the blurry image could be attributed to light scattering from the rough surface. Ethyl cellulose was used to fill the interior of the microbubble to obtain a clearer image. To determine the protective potential of this filling material, the chemical and mechanical properties of coated film after dry heat, hygrothermal and UV accelerated ageing were measured. Based on the above-mentioned results, it is encouraging that a new microrepair method and its corresponding method are offered in film treatment work.

The Treatment of Microbubble Disease of 20th Century Cellulose Acetate Microfilm: Application of Ethyl cellulose and Microrepair Method

Microbubble disease observed in cellulose acetate microfilm is accompanied by the production of vinegar syndrome, which affects the image integrity. In the present study, samples of cellulose acetate microfilm with microbubble disease were selected to investigate potential treatment methods. Samples were sourced from the Republic of China (AD 1912-1949) microfilm collections held in the Second Historical Archives of China. A combination of optical microscopy and a stainless-steel needle was used to remove plasticizer exudation within microbubbles. The plasticizer was effectively removed by infiltrating butan-1-ol into the microbubble from a small hole made by the stainless-steel needle. SEM and confocal microscopy were used to study the morphology and roughness of the internal surface of the microbubbles. It was found that the blurry image could be attributed to light scattering from the rough surface. Ethyl cellulose was used to fill the interior of the microbubble to obtain a clearer image. To determine the protective potential of this filling material, the chemical and mechanical properties of coated film after dry heat, hygrothermal and UV accelerated ageing were measured. Based on the above-mentioned results, it is encouraging that a new microrepair method and its corresponding method are offered in film treatment work.

On-Line Sorbentless Cryogenic Needle Trap and GC–FID Method for the Extraction and Analysis of Trace Volatile Organic Compounds from Soil Samples

In this study, an automated sorbentless cryogenic needle trap device (ASCNTD) coupled with a gas chromatograph (GC) was developed with the aim of sampling, pre-concentration and determination of volatile organic compounds (VOCs) from soil sample. This paper describes optimization of relevant parameters, performance evaluation and an illustrative application of ASCNTD. The ASCNTD system consists of a 5 cm stainless steel needle passed through a hollow ceramic rod which is coiled with resistive nichrome wire. The set is placed in a PVC (Polyvinyl chloride) chamber through which liquid nitrogen can flow. The headspace components are circulated with a pump to pass through the needle, and this results in freeze-trapping of the VOCs on the inner surface of the needle. When extraction is completed, the analytes trapped in the inner wall of the needle were thermally desorbed and swept by the carrier gas into the GC capillary column. The parameters being effective on the extraction processes, namely headspace flow rate, the temperature and time of extraction and desorption were optimized and evaluated. The developed technique was compared to the headspace solid-phase microextraction method for the analysis of soil samples containing BTEX (Benzene, Toluene, Ethylbenzene and Xylene). The relative standard deviation values are below 8% and detection limits as low as 1.2 ng g−1 were obtained for BTEX by ASCNTD.

The Treatment of Microbubble Disease of 20th Century Cellulose Acetate Microfilm: Application of Ethyecellulose and Microrepair Method

Microbubble disease observed in cellulose acetate microfilm was accompanied by the production of vinegar syndrome, which has a negative influence on the integrity of image. In the present study, cellulose acetate microfilm with microbubble disease from the Republic of China (AD 1912-1949) collected in the Second Historical Archives of China was chosen as a prototype to investigate its treatment methods. A combination of optical microscopy and a stainless-steel needle was used to remove plasticizer exudation within microbubbles. The plasticizer was effectively removed by infiltrating butan-1-ol into the microbubble from a small hole made by the stainless-steel needle. The SEM and laser confocal microscopy were used to study the morphology and roughness of the internal surface of microbubble. It was found that the blurry image could be attributed to the light scattering from the rough surface. Based on the advantages of ethyl cellulose in conservation science, the optimal concentration of ethyl cellulose was selected and used to fill the interior of the microbubble to obtain a clearer image. To determine the protective potential of this filling material, the chemical and mechanical properties of coated film after dry heat, hygrothermal and UV accelerated ageing were measured. Based on the above-mentioned results, it is encouraging that a new microrepair method and its corresponding method are offered in film treatment work.

Evaluation of histological specimens obtained by two types of EBUS-TBNA needles: a comparative study

Background Endobronchial ultrasound-guided transbronchial needle aspiration is a standard method for obtaining specimens of mediastinal and hilar lesions. Several types of needles of various sizes and materials are available. This study aimed to compare the quality of specimens collected using two needles, cobalt chromium and stainless steel for endobronchial ultrasound-guided transbronchial needle aspiration. Methods This retrospective study included data of patients who underwent EBUS-TBNA with a 22-gauge needle made from either stainless steel (41 lesions, 121 punctures) or cobalt chromium (47 lesions, 145 punctures). Histological data per puncture, diagnostic yield per lesion, procedure time and complication rates were compared. Results There were no significant differences between the groups in the baseline characteristics of the patients or lesions or in the complication rates. The rate of diagnostic histological specimens in each sample (71.0% vs. 58.7%, P = 0.039), fewer samples with cartilage alone (1.4% vs. 6.6%, P = 0.047) and fewer samples containing cartilage (7.6% vs. 16.5%, P = 0.034) were seen in the cobalt chromium needle group than in the stainless steel needle group. In both groups, the rate of specimens that only contained blood clots in each sample and diagnostic yield per lesion were similar, but the procedure time was significantly shorter (22 min vs. 26 min, P = 0.007) in the cobalt chromium needle group. Conclusion Compared with stainless steel needles, cobalt chromium needle for EBUS-TBNA showed lower cartilage contamination and a higher ratio of obtaining diagnostic specimens in each sample. Bronchoscopists should consider using the optimal needle gauges and materials for collecting adequate specimens.

Development of Microneedle Puncture Device that Prevents Buckling of Needle by Delivery Operation

Herein, using the micromachining technology, we propose a microneedle delivery mechanism that is similar to the lead delivery mechanism for a mechanical pencil. This mechanism involves three parts: a needle grasping part, a needle advancing part, and a needle retainer. This mechanism advances the needle by repeating the following steps: 1) fix the needle in the grasping part; 2) simultaneously advance the grasping part and the needle using the advancing part; 3) release the needle from the grasping part; 4) retreat the grasping and the advancing parts to their initial positions. This operation advances the needle very slowly, thereby allowing the needle to puncture the skin without buckling, even if the needle has a narrow diameter. Each component of the puncture device was cut from a plastic plate using a femtosecond laser. We evaluated the performance of the device for a stainless steel needle of φ100 μm, and were successful in delivering the needle at approximately 100 μm/cycle under a no-load condition. We also succeeded in puncturing the same needle into a hydrogel (Young’s modulus of ∼0.08 MPa) using this device.

Effect of acupuncture on the haemodynamic system in men

Background: Acupuncture stimulation decreases heart rate (HR) through somato-autonomic reflexes. However, the mechanisms responsible for other cardiovascular changes induced by acupuncture, such as its effects on stroke volume (SV) and blood pressure (BP), remain obscure. Objective: To evaluate continuously the comprehensive cardiovascular changes occurring during acupuncture. Method: 20 healthy men participated in the study. HR, SV and BP were measured in the supine position using electrocardiogram, transthoracic impedance cardiography and continuous non-invasive finger blood pressure, respectively. Manual acupuncture stimulation using a stainless steel needle was performed at LI10 for 60 s after resting periods of approximately 15 min. Results: HR was reduced and SV increased, in parallel, during the period of acupuncture stimulation (P<0.01, respectively). Diastolic blood pressure (DBP) decreased in the 10 s period of acupuncture stimulation compared with the 120 s pre-stimulation period (P<0.01) and recovered close to the pre-stimulation reading instantly after the transient reduction. No change was observed in cardiac output (CO) derived from HR and SV. Conclusions: This study indicates that HR reduction during acupuncture does occur, as previous reports have indicated. SV increased during acupuncture stimulation in parallel with HR reduction and CO was maintained during these changes. Any reduction in DBP caused by acupuncture recovered to baseline, likely due to baroreflexes.

Polypyrrole-coated needle as an electrospray emitter for ambient mass spectrometry

A method employing a stainless steel needle coated with PPy film for analyte extraction and subsequent analysis by electrospray ionization mass spectrometry (ESI-MS) under ambient and open-air conditions are shown.