The removal of three kinds of occlusal veneers by Er: Yag laser / 华西口腔医学杂志

OBJECTIVES@#This study aimed to remove occlusal veneers of varied thicknesses and compositions by Er:Yag laser in vitro and analyze the interfacial microstructure between veneers and tooth that irradiated by laser, by which experimental evidence could be provided to support the non-invasive removal of occlusal veneerby laser.@*METHODS@#Fresh mandibular premolars extracted for orthodontic requirements were collected for tooth preparation. Three kinds of ceramic materials (Vita Suprinity, Vita Mark Ⅱ, and Upcera Hyramic) were selected to fabricate occlusal veneer with different thicknesses (1.0, 1.5, and 2.0 mm). One week later, Er:Yag laser (2.5 W and 3.5 W) was used to irradiate and remove the occlusal veneer and recorded the timespan. After the removal operation, the micro-morphologies of samples were examined by scanning electron microscope.@*RESULTS@#Upcera Hyramic veneer failed to be removed (>20 min); the operation span at 2.5 W, Vita Suprinity (96.0 s±16.0 s) was longer than Vita MarkⅡ(84.5 s±19.5 s) in the 1.0 mm group (P<0.05), and Vita Suprinity (246.5 s±13.5 s) was longer than Vita MarkⅡ(170.0 s±14.0 s) in the 1.5 mm group (P<0.05). At 3.5 W, Vita Suprinity (381.0 s±24.0 s) was longer than Vita MarkⅡ(341.5 s±26.5 s) in the 2.0 mm group.@*CONCLUSIONS@#Increasing laser power could shorten the operation span and facilitate the removal of occlusal veneers with the same thickness and composition. The occlusal veneer was sustained when insufficient laser power was applied. With the same laser power and ceramic thickness, laser penetration could interfere with the integral of the ceramic structure when the laser interacted with the bonding layer. With the same ceramic composition and laser power, the operation span and laser power increased with the thickness of the occlusal veneer. However, the laser was incapable of removing occlusal resin veneer directly.

Determining age of high-explosive to support nuclear warhead dismantlement verification.

The future international nuclear disarmament may involve the dismantlement of nuclear warheads. After the dismantlement of a nuclear warhead, the separated explosive needs authentication that it comes from the dismantled nuclear warhead. In this paper, the Monte Carlo numerical simulation method was used to study the feasibility and result of determining the source of the explosive by analyzing the nuclide abundances of the explosive and determining the age of the explosive (calculated since the explosive was placed in the nuclear warhead). First, the JMCT software was used to analyze the nuclei produced by the neutron reactions in the explosive of the nuclear warhead. As a result, it was found that 14C is the most promising to be used to determine the source of the explosive. Second, the relationships between the average abundance of 14C and the age of the explosive, the spatial distribution of the 14C abundance in the explosive were calculated by using the JMCT software. Finally, it is found that, compared to the WgPu warheads (nuclear warheads with weapons-grade plutonium cores), the 14C abundances of the explosives of the WgU warheads (nuclear warheads with weapons-grade uranium cores) are much lower (the ages of the explosives are the same), and it is more difficult to measure the latter; for the WgPu warheads with the structures based on Model 3 and Model 4 (the warhead models employed were proposed by Steve Fetter), it can be determined that whether the separated explosives come from the dismantled nuclear warheads or are common ones (or the fake ones prepared by the verified party) after the dismantlement of the nuclear warheads by measuring the 14C abundances in the explosives (including the average abundances and the spatial distributions of the abundances) and determining the ages of the explosives, which realizes the source authentication of the explosives.

Effects of parecoxib sodium and fentanyl multimodal analgesia on immune functions in patients undergoing hepatectomy for hepatocellular carcinoma / 中华普通外科杂志

Objective To investigate the effects of multimodal analgesia of parecoxib and fentanyl on perioperative immune functions in patients of hepatocellular carcinoma (HCC).Methods Eighty HCC patients scheduled for hepatectomy were randomly divided into two groups:parecoxib sodium combined with fentanyl group (group P,40 cases) and fentanyl group (group C,40 cases).The percentages of CD3 +,CD4+,CD8+,CD4+/CD8+ T cells,CD3-CD16+ CD56+ (NK),interleukin-4 (IL-4),interferon-γ (IFN-γ) and the ratio of IFN-γ/IL-4 were detected at the following time points:30 minutes before induction of anesthesia (T0),at the end of the surgery (T1),24 h after surgery (T2) and 72 h after surgery (T3).The analgesic effects were estimated by visual analogue scale (VAS) after surgery.Total fentanyl consumption and adverse effects were also recorded.Results The percentages of CD3 + T cells were significantly lower in group C than that in group P at T2 (t =2.155,P ＜0.05).The percentages of NK in group P were recovered nearly to baseline (T0) at T2,which was higher than that of group C (t =2.791,P ＜0.05).In group C,the percentages of CD3 + T cells and NK has not recovered to baseline at T3 (respectively t =3.065,3.231,P ＜ 0.05).In group P,IL-4 serum levels were significantly lower than those in group C,while IFN-γ serum levels were significantly higher than those in group C at T2 (respectively t =2.173,2.100,P ＜0.05).From T2 to T3,the ratio of IFN-γ/IL-4 significantly increased in group P than those in group C (respectively t =3.259,2.203,P ＜ 0.05).VAS scores at rest and on cough in group P were significantly lower than those in group C at 2 h,6 h,12 h and 24 h after operation (respectively t =8.661,9.726,9.147,7.109,P＜0.05;t =8.569,9.614,9.144,8.509,P＜0.05).The total fentanyl consumption in group P was lower than that in group C (t =2.636,P ＜ 0.05).There were no significant differences regarding the incidence of adverse effects between the two groups.Conclusions Perioperative multimodal analgesia of parecoxib sodium combined with fentanyl enhances the analgesic efficacy,and reduces the dosage of opioid consumption,helps recover the cell immunity function of HCC patients after hepatectomy.

Advancement in researches of the effects of perioperative analgesia on immune function of cancer patients / 国际外科学杂志

Perioperative immunosuppression exists in cancer patients are as a result of their own disease,and postoperative pain inhibit immunological function.The effective postoperative analgesia can relieve the suppression of cell-mediated immunity,as well as reducing tumor recurrence and metastasis.However,diverse range of analgesic agents and techniques have a different impact on immune function.This article reviews the influence of various analgesic agents and techniques on the perioperative immune function of cancer patients so as to provide more suitable analgesia techniques,which is beneficial for regulating of immune balance,lessening tumor recurrence and improving prognosis.

Precision right hemihepatectomy combined with caudate lobectomy for the treatment of huge carcinoma in the caudate lobe / 中华消化外科杂志

Hepatectomy for huge hepatocellular carcinoma (HCC) is difficult due to its huge size and the compression and invasion to the surrounding tissues as well as the important vascular systems.Surgical resection of huge carcinoma in the caudate lobe is a big challenge for hepatobiliary surgeons because of its special location and complex anatomical structure.As the improvement of surgical techniques in recent years,especially the promotion of the concept of precision liver surgery,many surgeons begin to take the challenge of resection of huge HCC in the caudate lobe in a variety of ways.In April 2014,a male patient aged 58 years with huge HCC in the caudate lobe was admitted to the Anhui Provincial Hospital.Precision right hemihepatectomy combined with caudate lobectomy was performed on this patient without occlusion of the hepatic inflow,and the efficacy was satisfactory.The key techniques involved in this procedure were discussed in this article.

DNA methylation and hepatocellular carcinoma / 国际外科学杂志

Hepatocellular carcinoma is one of the most common cancer with a high incidence and mortality,representing a main type of primary liver cancer.However,the molecular and cellular mechanisms of hepatocellular carcinoma pathogenesis are still poorly understood.Traditionally,the development of hepatocellular carcinoma has been viewed as a process of transforming of normal cells into malignant driven by the genetic alterations in tumor-suppressor gene deactivation and pro-oncogene activation.In recent years,with the deeper understanding of tumor,it has been found that epigenetic alterations are closely related to the occurrence and the development of hepatocellular carcinoma.DNA methylation is one of the most common epigenetic events occurring in human genome,as well as the best studied of the epigenetic changes.This review focuses on the state-of-the-art advancements of DNA methylation in hepatocellular carcinoma.

Mesenchymal stem cells from mouse bone marrow are committed to differentiate into active melanocytes in vitro: an experimental study / 中华皮肤科杂志

Objective To explore the possibility of bone marrow mesenchymal stem cells (MSCs) differentiating into active melanocytes in vitro.Methods Bone marrow stromal cells were harvested from femoral marrow of 6-week-old black male C57BL/6 mice,and subjected to a primary culture.After 6-passage subculture,an induction medium containing hydrocortisone,recombinant human insulin,transferrin and fibroblast growth factor was used to induce the differentiation of MSCs into melanocytes.Inverted light microscopy was applied to observe the process of cell differentiation,transmission electron microscopy to observe melanosome formation and maturation,and immunocytochemistry to determine the expression of melanocyte-associated epitopes,and flow cytometry to analyze cell cycles and yield of differentiated melanocytes.Results The total number of MSCs was close to 109 after 6 passages of subculture,and immunofluorescent studies showed an expression rate of 94.3％ for CD44 and 82.3％ for CD105 in these MSCs.After 180-day cultivation in the induction medium,the MSCs showed a morphological similarity to melanocytes with an increase in dendrites,formation of melanosome-like structures,and cell growth cycle was shortened to 3-4 days.Brown/black cell sediments were visualized by naked eyes.Electron microscopy revealed that intracellular melanosomes were mainly in Ⅳ phase.Immunofluorescence studies of the differentiated melanocytes showed a positive staining for tyrosinase related protein-1 (TRP-1),TRP-2,and microphthalmia-associated transcription factor (MITF).Flow cytometric analysis showed that most of the melanocytes differentiated from the MSCs were in G1 and S phases,and TRP-1-positive melanocytes amounted to 80％ of gate cells.Conclusions Bone marrow MSCs can be largely differentiated into melanocytes with a close similarity to normal melanocytes in morphology,ultrastructure and specific epitopes and a certain degree of proliferative activity.