Effect of nanosecond- and microsecond-pulse Er,Cr:YSGG laser ablation on dentin shear bond strength of universal adhesives.

OBJECTIVE: The study aimed to evaluate the bond strength of universal adhesives to dentin after Er,Cr:YSGG laser irradiation with nanosecond-domain and microsecond-domain pulses. METHODS: Eighty extracted caries-free, sound human molars were divided into eight groups. The enamel was removed until the dentin occlusal flat dentin surface was exposed. Etch-and-rinse followed by adhesive was applied to group 1, and a self-etch adhesive was applied to group 2. Er,Cr:YSGG laser (3 mJ, 100 Hz, 100 ns), (3 mJ, 100 Hz, 150 µs), and (20 mJ, 100 Hz, 150 µs) were applied to groups 3-4, 5-6, and 7-8, respectively. The laser preparation was followed by self-etch adhesives or adhesives treatment. When the composite resin had been built up on the samples, the shear bond strength was tested, and the data were statistically analyzed using analysis of variance (ANOVA). RESULTS: Groups prepared with nanosecond-pulse laser showed significantly higher bond strength values than the microsecond-pulse laser groups and self-etch mode group, and the SEM photographs also showed more dentinal tubules and no damage in the ablation area. The shear bond strength of long pulse laser ablated was comparable to that of self-etching system when it was combined with a self-etch adhesive at low energy, but higher energy laser degraded shear bond strength. CONCLUSIONS: The pulse width of Er,Cr:YSGG laser affects the bond strength, nanosecond pulses of laser irradiation without water cooling can enhance bond strength, but microsecond pulses of laser cannot enhance bond strength.

2.79-µm efficient acousto-optic Q switched Er,Cr:YSGG laser with an LiNbO3 crystal modulator.

We fabricate a novel, to the best of our knowledge, acousto-optic Q switch in the 3-micron wavelength range using a longitudinal acoustic mode in a lithium niobate (LiNbO3) crystal. The device is designed based on properties of the crystallographic structure and material to obtain a high diffraction efficiency close to the theoretical prediction. The effectiveness of the device is verified by application in an Er,Cr:YSGG laser at 2.79 µm. The maximum diffraction efficiency reached 57% at the radio frequency of 40.68 MHz. At the repetition rate of 50 Hz, the maximum pulse energy was 17.6 mJ and the corresponding pulse width was 55.2 ns. The effectiveness of bulk LiNbO3 as an acousto-optic Q switch is verified for the first time.

High-peak-power electro-optically Q-switched laser with a gradient-doped Nd:YAG crystal.

We report on a high-peak-power electro-optically Q-switched laser emitting a near-diffraction-limited beam profile at 1064 nm by using a gradient-doped Nd:YAG crystal. The gradient-doped crystal features a unique combination of a reduced thermal lens effect through effectively spreading the heat load distribution within its volume. Its performance is compared with those of Nd:YAG crystals with uniform volume doping distribution operating in the Q-switched regime with the same laser configuration, demonstrating the higher average and peak power achievable with the gradient-doped crystal. The maximum average output power amounts to 6.9 W at a pulse repetition rate of 2 kHz, which corresponds to a maximum peak power of ∼585kW. Compared to homogeneous dopant crystals, the slope efficiency and average output power increased by 30.8% and 21.1%, respectively.

Effects of Dentin Ablation by a Q-Switching Er:YSGG Laser with a High Pulse Repetition Rate.

Objective: The aim of the study was to evaluate the characteristics of dentin ablation with a high pulse repetition rate Q-switching 2.79 µm laser. Materials and methods: Dentin was ablated using a homemade Q-switching Er:YSGG laser with a high pulse repetition rate. Er:YSGG radiation was applied with a pulse energy of 1 or 10 mJ for 100 or 3 Hz pulse repetition rate, respectively. A scanning electron microscope (SEM) was used to observe the microstructures of dentin samples after ablation. Teeth were irradiated in vitro with a 100 Hz pulse repetition rate under two different modes: free running and Q-switching. A thermocouple was applied to measure the temperature in the pulp cavity during ablation. Results: A 100 or 3 Hz Q-switching laser was used to irradiate dentin for 30 and 100 sec, respectively. There was no significant difference in ablation mass loss between the two conditions. The SEM photographs showed more dentinal tubules and no damage in the ablation area when using the 100 Hz Q-switching laser. The temperature of the pulp cavity was maintained below 41°C when using a Q-switching laser. Conclusions: The Q-switching Er:YSGG laser with a high pulse repetition rate exhibited greater ablation efficiency and better morphology than the low pulse repetition rate Q-switching laser. The experimental results also demonstrate the significant advantage of the Q-switching laser over free-running lasers for protecting dental pulp tissue. The Q-switching Er:YSGG laser with a high pulse repetition rate is expected to become an efficient new dental tool.

High-conversion-efficiency tunable mid-infrared BaGa4Se7 optical parametric oscillator pumped by a 2.79-µm laser.

A mid-infrared BaGa4Se7 optical parametric oscillator with high conversion efficiency and beam quality is demonstrated, which is pumped by a 2.79-µm electro-optically Q-switched Cr, Er:YSGG laser. A pulse energy of 3.5 mJ with a pulse width of 21 ns at 10 Hz is obtained in the range of 3.94-9.55 µm, and the beam quality factors are measured to be Mx2=5.0 and My2=4.6. The optical-to-optical conversion efficiency is 18.9%, and the slope efficiency is 31.6%, which is a 59% improvement on the best of the previously reported slope efficiencies for BaGa4Se7-based OPOs.

Recurrence risk after preoperative biopsy in patients with resected early-stage non-small-cell lung cancer: a retrospective study.

BACKGROUND: Tumor cell dissemination after needle biopsy has been reported in a variety of malignancies, including non-small-cell lung cancer (NSCLC). However, there is little clinical evidence in regard to whether preoperative biopsy increases the risk of recurrence in completely resected NSCLC. PATIENTS AND METHODS: A total of 322 patients diagnosed as pathological stage I NSCLC using intraoperative biopsy (IOB) (control group), preoperative percutaneous needle biopsy (PNB) or bronchoscopic biopsy were included in this study. Baseline characteristics were collected and compared. The disease-free survival (DFS) of patients was analyzed using Kaplan-Meier method. Subgroup analysis and Cox regression were performed to evaluate the effect of preoperative biopsy on recurrence risk with adjustment for potential confounders. RESULTS: Among these patients, 202 (63%) underwent IOB, 66 (20%) underwent PNB, and 54 (17%) underwent bronchoscopic biopsy. DFS of patients who had preoperative PNB or bronchoscopic biopsy was similar to those who had IOB (P=0.514 and 0.869). Neither preoperative PNB nor transbronchial biopsy significantly affected recurrence incidence across all the relevant subgroups. Furthermore, multivariate analysis showed that preoperative biopsy was not associated with increased recurrence risk in NSCLC patients with adjustment for confounders, while squamous cell carcinoma and adjuvant chemotherapy were associated with prolonged DFS. CONCLUSION: Neither preoperative PNB nor bronchoscopic biopsy increased the recurrence risk in patients with resected stage I NSCLC, indicating that these procedures could be safely used for diagnosis of early-stage NSCLC.

The Prediction of the Gas Utilization Ratio based on TS Fuzzy Neural Network and Particle Swarm Optimization.

Gas utilization ratio (GUR) is an important indicator that is used to evaluate the energy consumption of blast furnaces (BFs). Currently, the existing methods cannot predict the GUR accurately. In this paper, we present a novel data-driven model for predicting the GUR. The proposed approach utilized both the TS fuzzy neural network (TS-FNN) and the particle swarm algorithm (PSO) to predict the GUR. The particle swarm algorithm (PSO) is applied to optimize the parameters of the TS-FNN in order to decrease the error caused by the inaccurate initial parameter. This paper also applied the box graph (Box-plot) method to eliminate the abnormal value of the raw data during the data preprocessing. This method can deal with the data which does not obey the normal distribution which is caused by the complex industrial environments. The prediction results demonstrate that the optimization model based on PSO and the TS-FNN approach achieves higher prediction accuracy compared with the TS-FNN model and SVM model and the proposed approach can accurately predict the GUR of the blast furnace, providing an effective way for the on-line blast furnace distribution control.

Widely tunable and narrow-bandwidth pulsed mid-IR PPMgLN-OPO by self-seeding dual etalon-coupled cavities.

Integrating narrow-bandwidth and wavelength tunability together is crucially important in upgrading the applications of optical parametric oscillators (OPO). Here, we have demonstrated a widely tunable, narrow-bandwidth and efficient mid-IR OPO pumped by a single-longitudinal-mode pulsed Yb-fiber laser. By restricting the bandwidth of the oscillated signal via self-seeding dual etalon-coupled cavities, the bandwidth of the idler can be suppressed to about 0.35 nm, with a wide tunable range of 2.85-3.05 µm, which can be achieved by synergistically adjusting the temperatures of PPMgLN crystal and one of the etalons. The maximum idler power at 3.031 µm is 2.67 W with an optical-to-optical conversion efficiency of 17.4%.

Simultaneous Improvement of Resolving Power and Signal-to-Noise Ratio Using a Modified Hadamard Transform-Inverse Ion Mobility Spectrometry Technique.

In order to improve the resolving power (RP) and signal-to-noise ratio (SNR) of ion mobility spectrometry (IMS) simultaneously, a modified Hadamard transform-inverse ion mobility spectrometry (MHT-IIMS) technique was developed. In this novel technique, a series of isolating codes were appended to each element of the pseudo random binary sequence (PRBS), and then the modified modulation sequence was formed and used to control the ion gate of the inverse IMS (IIMS). Experimental results demonstrate that the MHT-IIMS technique can significantly enhance the resolving power and SNR simultaneously by measuring the spectra of reaction ions. Furthermore, the gas sample CCl4 and CHCl3 were measured for evaluating the capability of detecting those samples which have single and multiple product ions. The results show that this novel technique is able to simultaneously improve the resolving power and SNR notablely for the real sample detection without any significant instrumental changes. Graphical Abstract ᅟ.

Exhaled breath online measurement for cervical cancer patients and healthy subjects by proton transfer reaction mass spectrometry.

Cervical cancer is a common cancer among women and has a high morbidity and mortality. The traditional clinical methods for cervical cancer screening are invasive and limited in terms of cost and time. There is an unmet clinical need for new methods to aid clinicians in the rapid screening and auxiliary diagnosis of cervical precancer. Recently, breath analysis has become an attractive approach for investigation of cancer biomarkers and shows great potential in cancer screening owing to its high sensitivity, quickness, and non-invasive nature. In this pilot study, breath analysis by proton transfer reaction mass spectrometry (PTR-MS) was utilized for online analysis of the exhaled breath of 13 cervical cancer patients and 34 female healthy volunteers. The Mann-Whitney U test and stepwise forward linear discriminant analysis were performed for data statistics. On the basis of the statistical analysis, four characteristic ions at m/z 76, 87, 93, and 121 were found for discriminating cervical cancer. The sensitivity and specificity were calculated to be 92.3% and 88.2%, respectively, using the stepwise discriminant analysis. The possible identities of characteristic ions were also discussed in detail. Although there are some uncertainties in the identification of these characteristic ions and more participants (including cervical cancer patients and healthy volunteers) are needed to further confirm the results, the results in this study demonstrate that the online breath test using PTR-MS is a promising approach for cervical cancer screening.

Glass bottle sampling solid phase microextraction gas chromatography mass spectrometry for breath analysis of drug metabolites.

Breath analysis is a non-invasive approach which may be applied to disease diagnosis and pharmacokinetic study. In the case of offline analysis, the exhaled gas needs to be collected and the sampling bag is often used as the storage vessel. However, the sampling bag usually releases some extra compounds, which may interfere with the result of the breath test. In this study, a novel breath sampling glass bottle was developed with a syringe needle sampling port for solid phase microextraction (SPME). Such a glass bottle scarcely liberates compounds and can be used to collect exhaled gas for ensuing analysis by gas chromatography-mass spectrometry (GC-MS). The glass bottle sampling SPME-GC-MS analysis was carried out to investigate the breath metabolites of myrtol, a multicompound drug normally used in the treatment of bronchitis and sinusitis. Four compounds, α-pinene, 2,3-dehydro-1,8-cineole, d-limonene and 1,8-cineole were found in the exhaled breath of all eight volunteers who had taken the myrtol. While for other ten subjects who had not used the myrtol, these compounds were undetectable. In the SPME-GC-MS analysis of the headspace of myrtol, three compounds were detected including α-pinene, d-limonene and 1,8-cineole. Comparing the results of breath and headspace analysis, it indicates that 2,3-dehydro-1,8-cineole in the breath is the metabolite of 1,8-cineole. It is the first time that this metabolite was identified in human breath. The study demonstrates that the glass bottle sampling SPME-GC-MS method is applicable to exhaled gas analysis including breath metabolites investigation of drugs like myrtol.

Mid-infrared ZGP-OPO with a high optical-to-optical conversion efficiency of 75.7.

We experimentally demonstrate a ZnGeP2 based optical parametric oscillator (ZGP-OPO) with a record of the optical-to-optical conversion efficiency. To improve the conversion efficiency, we design and construct a double-pass pumped high-gain OPO and a matched large-sized high-peak-power pump beam to suppress the spatial walk-off and conversion. Pulse energy of 19 mJ with pulse width of 27.8 ns at 5 Hz in the mid-infrared 3-5 µm waveband is obtained in the doubly resonated ZGP-OPO, the beam quality M2 is about 9.6, and the corresponding optical-to-optical conversion efficiency reaches up to 75.7%.

Rapid analysis and identification of meat species by laser-ablation electrospray mass spectrometry (LAESI-MS).

RATIONALE: Laser-ablation electrospray ionization mass spectrometry (LAESI-MS) was applied to analyze fresh meat species without sample pretreatment. The study demonstrates that the LAESI-MS technique is a promising, rapid and accurate method for meat identification using a protocol combining principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). METHODS: A focused IR-laser was used for meat sample ablation at a wavelength of 2940 nm. The ablated particulates were carried through a transfer PTFE tube using air as carrier gas, delivered to the electrospray plume and ionized. A TOF-MS was used to detect the ion signal. The raw mass spectra were analyzed using the PCA and PLS-DA protocol. RESULTS: Five fresh meat samples, chicken, duck, pork, beef and mutton, were identified by the developed LAESI-MS technique using the protocol combining PCA and PLS-DA. The discrimination accuracy of all meat species is 100%, and the score plot also shows good identifying ability. CONCLUSIONS: Five fresh meat samples were analyzed using the LAESI-MS technique. Each set of raw mass data was collected within 30 s and analyzed by the PCA and PLS-DA protocol. Eighteen, 19, 18, 17, and 15 markers for chicken, duck, pork, beef, and mutton, respectively, have been selected successfully for meat identification. The results demonstrate that LAESI-MS is a new reliable and rapid method for meat identification. Copyright © 2016 John Wiley & Sons, Ltd.

Exhaled gases online measurements for esophageal cancer patients and healthy people by proton transfer reaction mass spectrometry.

BACKGROUND: Esophageal cancer is a prevalent malignancy. There is a considerable demand for developing a fast and noninvasive method to screen out the suspect esophageal cancer patients who may undergo further clinical diagnosis. METHODS: The exhaled breathes from 29 esophageal cancer patients and 57 healthy people were directly measured using our home-made proton transfer reaction mass spectrometer (PTR-MS). Mann-Whitney U test and stepwise discriminant analysis were applied to identify the ions in the breath mass spectral data which can distinguish cancer cohort from healthy group. Receiver operating characteristics (ROC) analysis was also performed. RESULTS: Seven kinds of ions in the breath mass spectrum, viz., m/z 136, m/z 34, m/z 63, m/z 27, m/z 95, m/z 107 and m/z 45, have been found to distinguish between the esophageal cancer patients and healthy people with a sensitivity of 86.2% and a specificity of 89.5%, respectively. Compared with that from the healthy people, the breath mass spectra from esophageal cancer patients show that the mediant intensities of five kinds of ions were decrease and the rest two kinds of ions were increase. ROC analysis gave the area under the curve (AUC) of 0.943. CONCLUSIONS: This pilot study shows that the ionic characteristics of exhaled VOCs detected by PTR-MS may be used to differentiate between the esophageal cancer patients and the healthy people. Although the breath tests for more patients are needed to confirm such results, the present work indicates that the PTR-MS may be a promising method in the esophageal cancer screening.

Correlation between Plasma Level of Monocyte Chemotactic Protein 1 and Acute Aortic Dissection.

OBJECTIVE: To investigate the potential association between monocyte chemotactic protein 1(MCP-1)in plasma and acute aortic dissection(AAD). METHODS: A total of 110 patients with Stanford type A AAD who had received emergent surgical treatment in Xiangya hospital from September 2011 to September 2014 were enrolled in as the study group;meanwhile,110 patients with simple hypertension who had received treatment in department of cardiology were chosen as the control group. The plasma level of MCP-1 was measured and then compared between these two groups. RESULTS: The plasma level of MCP-1 in the study group was(257.79±86.52)pg/ml,which was significantly higher than that in control group [(136.57±48.84)pg/ml](P<0.001). CONCLUSION: There may be a correlation between plasma MCP-1 level and AAD.

Chest wall tumors: Diagnosis, treatment and reconstruction.

The aim of the present study was to determine a suitable procedure for the treatment of chest wall neoplasms with less potential risk and an increased rate of survival. Fifty patients with suspected chest wall malignancies were analyzed using various preliminary investigation tools. Whole-chest scanning was performed in all the patients. The patients were subsequently subjected to biopsies for further confirmation of the neoplasm. All such patients were then treated with a surgical approach and radiation therapy, with a follow-up period lasting up to six years. The majority of the patients showed improved survival rates relative to conventional therapies. The survival rates of patients suffering from osteosarcoma (78%) were higher those of patients with rhabdomyosarcoma (73%) and malignant small round cell tumors (64%). The survival and the mortality rates of the patients with synovial sarcoma and fibrosarcoma were the same. This study, which was conducted on a small group of patients, has provided guidance for further studies on tumors of the chest wall, which may, in turn, increase the longevity of affected patients.

Inhibition of microRNA-101 attenuates hypoxia/reoxygenation­induced apoptosis through induction of autophagy in H9c2 cardiomyocytes.

Autophagy is a cellular self­catabolic process responsible for the degradation of proteins and organelles. Autophagy is able to promote cell survival in response to stress, and increased autophagy amongst cardiomyocytes has been identified in conditions of heart failure, starvation and ischemia/reperfusion. However, the detailed regulatory mechanisms underlying autophagy in heart disease have remained elusive. MicroRNAs (miRNAs) have been implicated in the regulation of autophagy in cells under stress. In the present study, the protective effect of miRNA (miR)­101 on hypoxia/reoxygenation (H/R)­induced cardiomyocyte apoptosis was investigated. It was revealed that H/R induced apoptosis in H9c2 cardiomyocytes, accompanied by a downregulation of miR­101 expression. Further investigation identified Ras­related protein Rab­5A (RAB5A) as a direct target of miR­101. RAB5A was previously reported to be involved in autophagy; therefore, the present study further focused on the role of miR­101 in the regulation of autophagy under H/R and found that the inhibition of miR­101 attenuated H/R­induced apoptosis, at least partially, via the induction of autophagy. In conclusion, the results of the present study revealed a beneficial effect of miR­101 inhibition on H/R­induced apoptosis in cardiomyocytes, indicating that miR­101 inhibition may present a potential therapeutic agent in the treatment or prevention of heart diseases.

High peak power Q-switched Er:YAG laser with two polarizers and its ablation performance for hard dental tissues.

An electro-optically Q-switched high-energy Er:YAG laser with two polarizers is proposed. By using two Al(2)O(3) polarizing plates and a LiNbO(3) crystal with Brewster angle, the polarization efficiency is significantly improved. As a result, 226 mJ pulse energy with 62 ns pulse width is achieved at the repetition rate of 3 Hz, the corresponding peak power is 3.6 MW. To our knowledge, such a high peak power has not been reported in literature. With our designed laser, in-vitro teeth were irradiated under Q-switched and free-running modes. Results of a laser ablation experiment on hard dental tissue with the high-peak-power laser demonstrates that the Q-switched Er:YAG laser has higher ablation precision and less thermal damage than the free-running Er:YAG laser.