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Needle-free injection is an alternative strategy to conventional needle injection in the field of drug delivery. This approach offers a number of advantages, especially in reducing complaints of needle phobia and avoiding the occurrence of accidental needle stick injuries. The ejection volume and orifice diameter are inherently important in determining the injection depth and percent delivery. In this study, we investigate the dispersion pattern of liquid penetration into gels and porcine tissues using a needle-free injector with ejection volumes of 0.05 to 0.35 mL and orifice diameters of 0.17 to 0.50 mm. In addition, the influence of the two parameters is analyzed quantitatively on the dispersion pattern through impact experiments and injection experiments. Furthermore, an equation of the jet power calculated by the ejection volume and orifice diameter is proposed to describe the delivery fraction of the injection experiments. Controls of the ejection volume and orifice diameter are demonstrated to help achieve a more effective injection process and a better injection experience.

Experimental equipments are designed for the zero-crossing method of dynamic laser speckles to investigate the moving nature of nanoparticles in flowing nanofluids. After the experiments the velocity of nanoparticles in flowing nanofluids is determined according to its relationship with the zero-crossing rate of speckle intensity fluctuation. The results show that the zero-crossing rate is very sensitive to the velocity of nanoparticles when the velocity of nanofluids ranges from 17.6 mm/s to 60.2 mm/s. A TEM10 mode–like laser beam is designed and taken as an incident light to detect the moving direction of nanoparticles in flowing nanofluids. The moving direction of nanoparticles is parallel to the horizontal axis of the TEM10 mode-like laser beam when the zero-crossing rate reaches maximum. Experimental results show that the moving direction of nanoparticles can also be detected by using the zero-crossing method.

With the aim of improving the efficiency of laser drilling, an upward drilling method is proposed. In the experiment, a long pulsed laser beam was arranged to propagate upwards, in the opposite direction to gravity, and was used to drill hole at the bottom of an aluminum slab. A semi-infinite axisymmetric model of this system was also established. The analytical solution for the hole shape was derived by assuming that material, once it melted, was removed from hole with the aid of gravity. The calculation results agreed well with the experimental results. For further verification of the effects of gravity, the removed molten material and the hole shape for the downward (along the gravity direction) and the upward drilling cases were compared experimentally. In addition, the relationships between gravity, the inertia force, the surface tension and the viscosity were discussed. The results show that more molten material is expelled with the assistance of the gravity, and the laser energy is used more efficiently to melt the aluminum slab in the upward drilling.

The scanning laser line source (SLLS) technique is a novel laser-based inspection method for the ultrasonic detection of small surface-breaking defects. The SLLS approach is based on monitoring the change in laser generated ultrasound as a laser line source is scanning over a defect. It has provided enhanced signal-to-noise performance compared to the traditional pitch-catch or pulse-echo ultrasonic methods. In this paper, an experimental method is presented to detect surface acoustic waves (SAW) with polyvinylindene fluoride(PVDF) transducer. The ultrasonic signal is converted into electric signal by piezoelectricity of the PVDF, which is attached to a micro-knife edge clamped on a metal device. The SAW are excited by employing a pulsed Nd:YAG laser on aluminum plate with artificial surface-breaking defects. The laser line source is accurately shifted by the motorized translation stage, while the PVDF is located at a fixed position on the specimen. When the laser line source is scanning over the defect, the ultrasonic signals are monitored, meanwhile the characteristic changes in the amplitude and frequency content are observed. Consequently, the position of the defect can be determined by analyzing the obtained signals. The experimental system with high sensitivity provides a detection method of small surface-breaking defects on metal and gives convincing experimental evidence for the interaction mechanism between the SAW and the surface-breaking defects.

In this paper, the LSD wave ignition process is analyzed. Interaction of an Nd:YAG laser and a pure Al target is investigated synchronously with a Mach-Zehnder interferometer, and series of interferograms of the ignition of an LSD wave and its propagation are obtained first. The propagating speed of the LSD wave and the pressure behind the LSD wave are obtained.

High-grade bleeding is a serious adverse event associated with bevacizumab, a humanized monoclonal antibody targeting vascular endothelial growth factor and widely used in the current cancer treatments. The aim of this study was to gain a better understanding of the overall incidence and risk of high-grade bleeding in cancer patients who receive bevacizumab therapy.We performed a meta-analysis of relevant randomized controlled trials (RCTs) identified in PubMed, Cochrane library, Embase, and American Society of Clinical Oncology conferences. Overall relative risks (RRs), incidence rates, and 95% confidence intervals (CIs) were calculated using a random-effects model. The primary clinical endpoint was high-grade bleeding (grade 3 or above).A total of 14,277 patients with a variety of solid tumors from 22 RCTs were included in the present analysis. The addition of bevacizumab to cancer chemotherapy significantly increased the risk of high-grade bleeding (RR 1.60, 95% CI 1.19-2.15), with RRs of high-grade bleeding among patients receiving bevacizumab at 2.5 and 5 mg/kg per week of 1.27 (95% CI 0.95-1.71) and 3.02 (95% CI 1.85-4.95), respectively. The overall incidence of high-grade bleeding among patients receiving bevacizumab was 2.8% (95% CI 2.1-3.8). Higher risks were observed in patients with non-small-cell lung cancer (RR 3.41, 95% CI 1.68-6.91), renal cell carcinoma (RR 6.37, 95% CI 1.43-28.33), and colorectal cancer (RR 9.11, 95% CI 1.70-48.79) who were receiving bevacizumab at 5 mg/kg per week.Among the patients included in the trials analyzed in this meta-analysis, the addition of bevacizumab to cancer chemotherapy significantly increased the risk of high-grade bleeding. The risk may be dose-dependent and may vary with tumor type.

Problems that cumber the development of the laser propulsion in atmosphere and vacuum are discussed. Based on the theory of interaction between high‐intensity laser and materials, as air and water, it is proved that transport in water environment can be impulsed by laser. The process of laser propulsion in water is investigated theoretically and numerically. It shows that not only the laser induced plasma shock wave, but also the laser induced bubble oscillation shock waves and the pressure induced by the collapsing bubble can be used. Many experimental results show that the theory and the numerical results are valid. The numerical result of the contribution of every propulsion source is given in percentage. And the maximum momentum coupling coefficient Cm is given. Laser propulsion in water environment can be applied in many fields. For example, it can provide highly controllable forces of the order of micro‐Newton (μN) in microsystems, such as the MEMS (Micro‐electromechanical Systems). It can be used as minimally invasive surgery tools of high temporal and spatial resolution. It can be used as the propulsion source in marine survey and exploitation.

Background Nosocomial infections are a major threat to patients in the intensive care unit (ICU). Limited data exist on the epidemiology of ICU-acquired infections in China. This retrospective study was carried out to determine the current status of nosocomial infection in China. Methods A retrospective review of nococomial infections in the ICU of a tertiary hospital in East China between 2003 and 2007 was performed. Nosocomial infections were defined according to the definitions of Centers for Disease Control and Prevention. The overall patient nosocomial infection rate, the incidence density rate of nosocomial infections, the excess length of stay, and distribution of nosocomial infection sites were determined. Then, pathogen and antimicrobial susceptibility profiles were further investigated. Results Among 1980 patients admitted over the period of time, the overall patient nosocomial infection rate was 26.8% or 51.0 per 1000 patient days., Lower respiratory tract infections (LRTI) accounted for most of the infections (68.4%), followed by urinary tract infections (UTI, 15.9%), bloodstream (BSI, 5.9%), and gastrointestinal tract (GI, 2.5%) infections. There was no significant change in LRTI, UTI and BSI infection rates during the 5 years. However, GI rate was significantly decreased from 5.5% in 2003 to 0.4% in 2007. In addition, A. baumannii, C. albicans and S. epidermidis were the most frequent pathogens isolated in patients with LRTIs, UTIs and BSIs, respectively. The rates of isolates resistant to commonly used antibiotics ranged from 24.0% to 93.1%. Conclusion There was a high and relatively stable rate of nosocomial infections in the ICU of a tertiary hospital in China through year 2003–2007, with some differences in the distribution of the infection sites, and pathogen and antibiotic susceptibility profiles from those reported from the Western countries. Guidelines for surveillance and prevention of nosocomial infections must be implemented in order to reduce the rate.

A new sensor based on optical beam shading technique for the investigation of mechanical effects during laser-metal interaction is developed. This sensor is applied to detect the laser-induced plasma explosive impact and deformation process during the explosion when a Q-switched laser is focused on a metal. The experimental results indicate that elastic deformation and plastic deformation associated with the event induced by laser plasma the same time. This technique has the advantages of high-frequency response, simple structure, and nondestructive examination.

In order to study the effect of viscosity on the mechanical effects during laser-metal interaction, the transient forces loading on a metal plate in various glycerol-water mixtures are investigated by a fiber-optic diagnostic technique based on optical beam deflection (OBD). The experimental results show that a target in glycerol mixtures is impacted in turn by laser-plasma ablation force and high-speed liquid-jet impulse induced by bubbles collapse in the vicinity of a solid boundary. The amplitudes of the two forces decrease monotonously with less laser energy. Furthermore, strong differences of mechanical effects are observed in the glycerol mixtures and water. Viscosity has the effect of dampening mechanical energy. And increased viscosity is seen to decrease the amplitudes of the two forces but increase bubble life-time.

In this paper harmonic oscillator is used to study the changes of levels of atomic hydrogen in intense laser field. A series energy eigenwerts of harmonic oscillator between the former levels are obtained.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A theoretical and experimental study is conducted to investigate applicability of a single-mode fiber ultrasonic sensor for detecting the shock-wave in optical breakdown in air induced by a high power laser pulse. The sensor is based on the ultrasonically induced modal birefringence which alters the polarization state of the optical beam propagating through the fiber. The shock-wave signals have been gotten by using the sensor. It is shown that the single-mode fiber sensor has enough sensibility to detect shock-wave in air, but it is dependent on the fiber- ultrasonic interaction length and the intensity of shock- wave.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The interaction process of a high-power laser and a PIN-junction optoelectronic diode has been studied theoretically and experimentally. It has been put forward that the thermal effect of laser beams and the eroding and washing effect while the laser plasmas expand out, results in the silicon photodiode to be damaged. The thermal distribution, the expression of the maximum temperature, have been obtained for the first time when a Q-switched Nd:YAG laser irradiated upon the PIN junction optoelectronic diode.

In this paper, the interaction process of high-power Q-switched YAG laser and MNOS-type charge-coupled devices (CCD) is studied with the help of plasma shape and structure under the repeated actions of laser pulses. Mach-Zehnder interferograms of plasmas and related experimental results produced by a 1064 nm laser beam with a pulse width of 15 ns acted upon the MNOS-type CCD are obtained for the first time.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An ophthalmic laser system is reported, when this laser is used to perform an operation, an interference effect can produce, then the laser power density acted upon local eye tissue is increased.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper, LSD wave ignition process is analyzed according to aerodynamics, and expressions of speed of LSD wave, pressure, internal energy is derived. Interaction of YAG laser and Al target is investigated synchronously with a Mach-Zehnder interferometer, and series of interferograms of ignition and propagation of LSD wave at the initial stage are obtained first. It presents reliable experimental datum for theoretical study of LSD wave.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The recording of multiplexing hologram on one holo film has been studied theoretically and verified experimentally in this paper, and it has been put forward that when multiframe holograms are recorded on one holo film, superposition and modulation of the interference fringes is the main cause to reduce the diffraction efficiency of some holograms having disperse fringes in the multiframe holograms.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Production of surface pressure, plasma formation and momentum transfer of target is analyzed in interaction between laser and target material in this paper, a low-energy and high-power 1.06 micrometers YAG laser with a pulse width of 15 ns is applied to act upon different target material surfaces, and by using a pendulum shift technique to measure displacement of the target surface, momentum transfer and momentum coupling coefficient are obtained at different conditions.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper, we used shapes of plasmas, which a Q-switched YAG laser acted repeatedly upon a CCD having MOS structure to produce, to investigate the destroying process of the optoelectronic device, and first obtained related experimental results of CCD to be destroyed by a 1.06 micrometers laser beam with a pulse width of 15 ns.

In this paper, 30 cases of extracapsular cataract extractions with the assistance of an Nd:YAG laser are reported. Myosis phenomenon in laser operation is observed and its producing mechanism is discussed. Laser ophthalmology was the earliest field in laser application research, and pulse Nd:YAG laser ophthalmic instruments have been developed rapidly because of unique advantages in the anterior and posterior capsulotomy and trabecula shaping method.

A treatment for eleven eyes on posterior capsular opacifications after artificial intraocular lens (IOL) implantations with an Nd:YAG laser is reported, and a secure range of laser energy under which IOLs are not injured in the operations is given in this paper.

In this paper, 30 cases of extracapsular cataract extractions with a Nd:YAG laser are reported. Myosis phenomenon in laser operation is observed and its producing mechanism is discussed. Laser ophthalmology was the earliest field in laser application research, and pulse Nd:YAG laser ophthalmic instruments have been developed rapidly because of unique advantages in the anterior and posterior capsulotomy and trabecula shaping method. Thirty cases of extracapsular cataract extractions with the assistance of a Nd:YAG laser are reported in this paper. In laser operation, myosis phenomenon is observed, and its production mechanism is discussed.

Microplasma and shock waves produced by a Q-switched YAG pulse laser worked near the optical breakdown threshold of physiological saline are investigated by using optical shadowing exploring method. A series of optical shadowgraphs of microplasma and shock waves versus the incident laser energy and the delay time is obtained. The mechanical action of shock waves is discussed.

By using a Q-switched YAG laser and an optical path delay set-up, we study the process in which as laser induces breakdown to produce plasma in air. We obtained time-resolved Mach- Zehnder interferograms and optical shadowgrams of the initial stage of the plasma, and shock waves produced in the process are obtained.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

By using an optical path delay set-up, the instantaneous process in which a Q-switched YAG laser induces breakdown on an aluminum surface is studied. A series of time-resolved Mach- Zehnder interferograms and optical shadowgrams of the plasma and the shock wave during the initial stage is obtained. Plasma refractivity distribution and electron density on the shock front are computed.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The thermoelastic stress wave stimulated by laser inside a solid medium is studied theoretically and experimentally, and the speed of the wave inside epoxy resin is measured.

The plasmas produced in Q-switched laser actting repeatedly on two kinds of single-layer optical thin films are detected, and the field effect in this interaction process is analysed.

The influence of thermal effect induced by optical pumping on YAG crystal rod in a pulse solid laser on the wave surface of the output laser beam is studied in this paper. A series of time-resolved instantaneous interferograms during and after the pumping is obtained with a Mach—Zehnder interferometer, and three-dimension time-resolved pictures of the distorting wave surfaces and the curve of thermal focal length of laser rod versus time are gained after the treatment and calculation for interferograms.

The mechanism of laser-induced damage to thin films is described in this paper, and a definition of laser breakdown threshold to thin film, optical breakdown threshold is presented. The new definition is clearer than the existing one. The measurement results and comparison for various samples are given on the basis of the two above-mentioned definitions.

By using optical interference method, we have studied the process in which a Q—switched YAG laser induced an eye model to break down. It showed that the mechanical effect of the shock results in local discuption of iris. We have investigated the plasma shielding in the lipuid eye model, and put forward both the plasma shielding and the focusing angle of the incident laser are two important factors to protect the retina from injury in high power laser ophthalmology. I . INTRODUCTION Laser application in medicine, especially in ophthalmology has had a very rapid and great development for recent years 1,2) But it seems that people have overlooked the study of the physical mechanism about laser medicine. In this paper, experimental investigation for the physical mechanism of pulse laserophthalmology is tried. By using optical exploring method, the instantaneous physical process in whichhigh—power laser induced an eye model to break down to produce plasma is investigated, and a series of

By using optical interference and shadowing methods and an optical path delay set-up, the initial process of laser-induced self-focusing in H2 is studied on one Q-switched YAG laser and a series of time-resolved Mach-Zehnder interferograms and shadows are obtained. Some phenomena during the self-focusing are observed and explained. The theoretical model of moving foci is demonstrated by the experiments discussed in this paper.