Transcriptome alterations in zebrafish gill after exposure to different sizes of microplastics.

Most studies on microplastics (MPs) focused on gut, liver, and brain, and MPs toxicity was size-dependent, but less has been reported on gill. Here, zebrafish were exposed to three sizes of MPs (45-53 µm, 90-106 µm, and 250-300 µm). Next, comparative transcriptome analysis and determination of physiological indices were performed in zebrafish gills to elucidate the size-associated toxicity of MPs to fish gills. Compared with the control, 60, 344, and 802 differentially expressed genes (DEGs) were identified after exposure to 45-53 µm, 90-106 µm, and 250-300 µm MPs for 5 days, respectively. More DEGs in treatment with bigger MPs suggested that bigger MPs might induce more changes in zebrafish gills than smaller ones. These DEGs were significantly enriched in the FoxO signaling, cellular senescence, circadian rhythm and p53 signaling pathways. Besides, 90-106 µm and 250-300 µm MPs treatments inhibited the cell cycle and prevented the apoptosis. The GSH content significantly increased after MPs exposure, suggesting the induction of oxidative stress. AChE and Na+/K+-ATPase activities were significantly lowered in all MPs treatments than in the control, suggesting the inhibition of neurotransmission and ion regulation. These changes might negatively influence the normal functioning of gills, such as osmoregulation, ion regulation, and respiration.

The time-dependent variations of zebrafish intestine and gill after polyethylene microplastics exposure.

Microplastics (MPs) are common environmental contaminants that present a growing health concern due to their increasing presence in aquatic and human systems. However, the mechanisms behind MP effects on organisms are unclear. In this study, zebrafish (Danio rerio) were used as an in vivo model to investigate the potential risks and molecular mechanisms of the toxic effects of polyethylene MPs (45-53 µm). In the zebrafish intestine, 6, 5, and 186 genes showed differential expression after MP treatment for 1, 5, and 10 days, respectively. In the gills, 318, 92, and 484 genes showed differential expression after MP treatment for 1, 5, and 10 days, respectively. In both the intestine and the gills, Gene Ontology (GO) annotation showed that the main enriched terms were biological regulation, cellular process, metabolic process, cellular anatomical entity, and binding. KEGG enrichment analysis on DEGs revealed that the dominant pathways were carbohydrate metabolism and lipid metabolism, which were strongly influenced by MPs in the intestine. The dominant pathways in the gills were immune and lipid metabolism. The respiratory rate of gills, the activity of SOD and GSH in the intestine significantly increased after exposure to MPs compared with the control (p < 0.05), while the activity of SOD did not change in the gills. GSH activity was only significantly increased after MP exposure for 5 days. Also, the MDA content was not changed in the intestine but was significantly decreased in the gills after MP exposure. The activity of AChE significantly decreased only after MPs exposure for 5 days. Overall, these results indicated that MPs pollution significantly induced oxidative stress and neurotoxicity, increased respiratory rate, disturbed energy metabolism and stimulated immune function in fish, displaying an environmental risk of MPs to aquatic ecosystems.

Association Between Helicobacter pylori Infection and Risk of Periodontal Diseases in Han Chinese: A Case-Control Study.

BACKGROUND: This study was performed to test the association between Helicobacter pylori (HP) and periodontal disease (PD). MATERIAL/METHODS: This was a case-control study in a comprehensive hospital, including all patients with newly diagnosed PD between 2012 and 2014 as cases and all patients without PD as controls, thorough periodontal examinations. Those who tested positive for HP were examined by means of polymerase chain reaction. Single and multivariate logistic regression was used to analyze the data using SPSS 19.0 software. RESULTS: This case-control study included 212 Han Chinese non-smoking adults. The results indicated that HP-positive status significantly increased the risk of PD (2.63 times higher (odds ratio [OR]=2.63; 95% confidence interval [CI]=1.48-4.67). After adjustment for age, sex, level of education, physical exercise, body mass index, and history of alcohol and diabetes mellitus, this association remained significantly (OR=2.82, 95% CI=1.55-5.13). CONCLUSIONS: PD might be associated with HP infection in adults and HP infection may be a significant and independent risk factor for PD.

Autosomal recessive GJA1 (Cx43) gene mutations cause oculodentodigital dysplasia by distinct mechanisms.

Oculodentodigital dysplasia (ODDD) is mainly an autosomal dominant human disease caused by mutations in the GJA1 gene, which encodes the gap junction protein connexin43 (Cx43). Surprisingly, there have been two autosomal recessive mutations reported that cause ODDD: a single amino acid substitution (R76H) and a premature truncation mutation (R33X). When expressed in either gap junctional intercellular communication (GJIC)-deficient HeLa cells or Cx43-expressing NRK cells, the R76H mutant trafficked to the plasma membrane to form gap junction-like plaques, whereas the R33X mutant remained diffusely localized throughout the cell, including the nucleus. As expected, the R33X mutant failed to form functional channels. In the case of the R76H mutant, dye transfer studies in HeLa cells and electrical conductance analysis in GJIC-deficient N2a cells revealed that this mutant could form functional gap junction channels, albeit with reduced macroscopic and single channel conductance. Alexa 350 dye transfer studies further revealed that the R76H mutant had no detectable negative effect on the function of co-expressed Cx26, Cx32, Cx37 or Cx40, whereas the R33X mutant exhibited significant dominant or trans-dominant effects on Cx43 and Cx40 as manifested by a reduction in wild-type connexin gap junction plaques. Taken together, our results suggest that the trans-dominant effect of R33X together with its complete inability to form a functional channel may explain why patients harboring this autosomal recessive R33X mutant exhibit greater disease burden than patients harboring the R76H mutant.

pH-sensitive nano-polyelectrolyte complexes with arthritic macrophage-targeting delivery of triptolide.

Since pro-inflammatory macrophages take on a critical significance in the pathophysiology of rheumatoid arthritis (RA), the therapeutics to affect macrophages may receive distinct anti-RA effects. However, the therapeutic outcomes are still significantly impeded, which is primarily due to the insufficient drug delivery at the arthritic site. In this study, the macrophage-targeting and pH stimuli-responsive nano-polyelectrolyte complexes were designed for the efficient targeted delivery of triptolide (TP/PNPs) on the arthritic site. The anionic and cationic amphiphilic copolymers, i.e., hyaluronic acid-g-vitamin E succinate (HA-VE) and the quaternized poly (ß-amino ester) (QPBAE-C18), were prepared and then characterized. The result indicated that TP/PNPs with the uniform particle size of âˆ¼ 175 nm exhibited the high drug loading capacity and storage stability based on the polymeric charge interaction, in which DLC and DEE of TP/PNPs were obtained as 11.27 ± 0.44 % and 95.23 ± 2.34 %, respectively. Mediated by the "ELVIS" effect of NPs, CD44 receptor-mediated macrophage targeting, and pH-sensitive endo/lysosomal escape under the "proton sponge" effect, TP/PNPs exhibited the enhanced cellular internalization and cytotoxicity while mitigating the inflammation of LPS-activated RAW 264.7 cells. Even after 96-hour after administration, PNPs were preferentially accumulated in the inflammatory joints in a long term. It is noteworthy that after treatment for 14 days with 100 µg/kg of TP, TP/PNPs significantly facilitated arthritic symptom remission, protected cartilage, and mitigated inflammation of antigen-induced arthritis (AIA) rats, whereas the systematic side-effects of TP were reduced. In this study, an effective drug delivery strategy was proposed for the treatment of RA.

[A clinical study on reparation of orbital blowout fracture by bridge hydroxylapatite artificial bone].

OBJECTIVE: To explore a minimally invasive technique with hydroxylapatite artificial bone to repair the orbital blowout fracture. METHODS: Twenty-one cases of orbital blowout fracture from March 2008 to April 2010 were enrolled. And the fractures were repaired with a bridge of hydroxylapatite artificial bone under a nasal endoscope. During a regular 6-month follow-up, anatomic and functional recovery was evaluated. RESULTS: There was neither postoperative visual loss nor infection in all cases. At 3 months post-operation, diplopia vanished completely (n = 17), remained in peripheral vision (n = 2), existed in primary ocular position (n = 2) and the deviation of eyeball (n = 1). At Month 3, diplopia in peripheral vision or in primary position and the deviation of eyeball showed no improvement. Compared with the uninjured side, enophthalmos: ≤ 2 mm (n = 18), > 2 mm (n = 2) and > 4 mm (n = 1). The passive traction test was positive in one case. On computed tomograph (CT) scanning, there was no bone dislocation or slippage in all cases. CONCLUSION: The surgical efficacy is excellent. The technique of combining the advantages of endoscopic sinus approach and hydroxyapatite artificial bone is worth a wider popularization.

[Cockayne syndrome].

Cockayne syndrome is a rare autosomal recessive disease. This paper reports a case of Cockayne syndrome confirmed by gene analysis. The baby (male, 7 years old) was referred to Peking University Third Hospital with recurrent desquamation, pigmentation and growth and development failure for 6 years, and recurrent dental caries and tooth loss for 2 years. Physical examination showed very low body weight, body length and head circumference, yellow hair, a lot of fawn spots on the face, skin dry and less elastic, and subcutaneous lipopenia. He had an unusual appearance with sunken eyes, sharp nose, sharp mandible, big auricle and dental caries and tooth loss. Crura spasticity and ataxia with excessive tendon reflexion, and ankle movement limitation while bending back were observed. He had slured speech. The level of serum insulin like growth factor I was low, and the results of blood and urinary amino acid analysis suggested malnutrition. The results of blood growth hormone, thyroxin, parathyroxin, liver function, renal function, lipoprotein profile and blood glucose and electrolytes were all within normal limit. An electronic hearing examination showed moderate neural hearing loss. The sonogram of eyes revealed small eye axis and vitreous body opacity of right side. MRI of brain revealed bilateral calcification of basal ganglia and generalized cerebral and cerebellar atrophy, and brainstem and callus were also atrophic. Genetic analysis confirmed with CSA gene mutation. So the boy was definitely diagnosed with Cockayne syndrome. He was discharged because of no effective treatment.

Algal density affects the influences of polyethylene microplastics on the freshwater rotifer Brachionus calyciflorus.

Most previous researches focused on the toxicity of polystyrene microplastics (MPs) to marine organisms, but less on polyethylene MPs and freshwater zooplanktons. The present study aims to elucidate the toxicity of polyethylene (PE) MPs (diameter = 10-22 µm) to the typical freshwater rotifer Brachionus calyciflorus. Firstly, fluorescent microscope observation showed that rotifers could ingest PE MPs and accumulate them in their digestive tracts. Life-table experiments revealed that exposure to 0.5 × 103, 2.5 × 103, and 1.25 × 104 particles/mL PE MPs significantly reduced net reproductive rate and intrinsic rate of pollution increase of rotifers under algal densities (Scenedesmus obliquus) of 0.1 × 106, and 0.5 × 106 cells/mL, but no significant effects were observed under 2.5 × 106 cells/mL algal density. These results showed that PE MPs suppressed the reproduction of rotifer and this negative effect could be alleviated by increasing food supply. The swimming linear speed of rotifers significantly decreased with increasing MP concentrations. The activities of superoxide dismutase and Na+-K+-ATPase significantly decreased in treatments with high concentration of PE MPs under 0.1 × 106 cells/mL algal density, but did not change significantly in MP treatments under 0.5 × 106 and 2.5 × 106 cells/mL, compared to the control. Glutathione peroxidase activity significantly increased in treatments with 1.25 × 104 particles/mL and 2.5 × 103 particles/mL under 0.1 × 106 and 0.5 × 106 cells/mL algal density, respectively, but did not change significantly in all MP treatments under 2.5 × 106 cells/mL. Exposure to PE MPs might lower the gathering capacity of algae, induce oxidative stress, trigger cell membrane damages and disturb energy metabolism in rotifers, which can explain the PE MPs toxicity to rotifer reproduction.

[Characteristics and Health Risk Assessment of Heavy Metals in PM2.5 Under Winter Haze Conditions in Central China: A Case Study of Huanggang, Hubei Province].

To explore the pollution characteristics and potential health risks of heavy metals in PM2.5 on haze days in Central China, PM2.5 samples were collected from the Huanggang monitoring station, a regional observation point in Central China, between January 13 and 24, 2018. The contents of Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sn, and Pb in PM2.5 were analyzed by inductively coupled plasma mass spectrometry(ICP-MS), and the enrichment factor method was used to determine the potential risk based on the exposure model recommended by the Environmental Protection Administration(EPA). The results showed that during the observation period, the concentrations of Zn in PM2.5 were highest, and the concentrations of the carcinogens As and Cd were higher than the secondary standard limits of China's ambient air quality standard(GB 3095-2012), with 70% of these elemental concentrations accounting for the largest proportion in the middle haze period. The enrichment factor analysis showed that Cd, Sn, Co, Pb, and Zn were the most abundant elements, especially during the middle haze period, and were mostly derived from transportation and coal combustion. The results of the human health risk assessment showed that exposure via hand-mouth feeding was the main non-carcinogenic risk, and the exposure and non-carcinogenic risks of children were significantly higher than those of adults. Pb poses a non-carcinogenic risk to children, while heavy metals in PM2.5 pose no non-carcinogenic risks to adults and carcinogenic heavy metals pose no carcinogenic risks.

Improvement of the bioavailability of curcumin by a supersaturatable self nanoemulsifying drug delivery system with incorporation of a hydrophilic polymer: in vitro and in vivo characterisation.

OBJECTIVES: The current study was focused on preparing curcumin (CUR) supersaturated self-nano-emulsion (PI-CUR-SNEDDS) using hydrophilic polymer and to study the influence of polymer precipitation inhibitor on the physicochemical and biopharmaceutical properties of the PI-CUR-SNEDDS. METHODS: PI-CUR-SNEDDS were prepared using hydrophilic polymer in order to maintain the supersaturation of CUR in nano-emulsion solution, artificial gastrointestinal fluid (AGF), and the precipitates formed, and characterised by in vitro dispersion tests, in vitro intestinal absorption and in vivo pharmacokinetic and compared with CUR-SNEDDS. KEY FINDINGS: PI-CUR-SNEDDS prepared with 2% hydroxypropyl methylcellulose 55-60 (HPMC55-60) as precipitation inhibitor (PI) significantly improved the viscosity, physical stability and CUR's equilibrium solubility of nanoemulsion. HPMC55-60 and CUR interact in AGF through intermolecular interactions, form hydrogen bonds, and produce amorphous precipitates. Compared with CUR-SNEDDS, the proportion of CUR in the hydrophilic phase increased by about 3-fold, and apparent permeability coefficient (Papp) in duodenum, jejunum, ileum, and colon increased by 2.30, 3.65, 1.54 and 2.08-fold, respectively, and the area under the plasma concentration-time curve0-12h of PI-CUR-SNEDDS also increased by 3.50-fold. CONCLUSIONS: Our results suggested that HPMC55-60 maintained the CUR supersaturation state by forming hydrogen bonds with CUR, increasing the solution's viscosity and drug solubilisation, thus improving the absorption and bioavailability of CUR.

C2 pedicle screw and plate combined with C1 titanium cable fixation for the treatment of atlantoaxial instability not suitable for placement of C1 screw.

STUDY DESIGN: A method of atlantoaxial stabilization using individual fixation of the C1 posterior arch and the C2 pedicle with C2 pedicle screws and plates combined with C1 titanium cables is described. In addition, the clinical results of this method on 8 patients are described. OBJECTIVE: To describe the method and the clinical and radiographic results for posterior C1-C2 fixation with a combined implant system. SUMMARY OF BACKGROUND DATA: Stabilization of the atlantoaxial complex is a challenging procedure because of the unique anatomy of this region. Fixation by plate or rod and C1 and C2 screw and structural bone grafting leads to excellent fusion rates. The technique is technically demanding and has a potential risk of the injuries to the vertebral artery, the internal carotid artery, spinal cord, and hypoglossal nerves. In addition, how to stabilize the atlantoaxial complex in the cases not suitable for placement of C1 screw is not described in the literature. To address these limitations, a method of C1-C2 fixation has been developed: bilateral insertion of C2 pedicle screws and rolling of C1 titanium cable through the posterior arch of atlas and the cranial hole of the plate, followed by C1-C2 plate fixation. METHODS: From February 2003 to March 2006, 8 patients with atlantoaxial instability and not suitable for placement of C1 screw were included in this study: 5 cases of broken C1 pedicle screw trajectory and 3 cases of C1 anatomic anomalies. Skull traction was performed in each patient preoperatively. The pedicle screws were inserted into C2 pedicles in the direction as its axis. C1 titanium cable was rolled superior to lower through posterior arch of atlas in the cases not suitable for placement of C1 screw. The C1-C2 plate was slightly bent to fit the upper cervical contour. Hyperflexion alignment of the atlantoaxial complex was corrected by application of extension force created by tightening of the nut on the pedicle screws and the C1 titanium cable, which was passed through the cranial hole of the plate. Morselized autogenous cancellous iliac grafts were placed on the surface of the posterior arches of both atlas and axis. All patients were assessed clinically for neurologic recovery by Odom's method. RESULTS: There were 5 males and 3 females with a mean age of 37.8 years (range, 17 to 59 y). There were 2 cases of old odontoid fracture, 2 cases fresh odontoid fracture (Aderson II C), 2 cases atlas transverse ligament laxation, 2 cases atlas transverse ligament rupture, and in these cases, 5 cases had failed placement of C1 screw because of broken C1 pedicle screw trajectory and 3 cases not suitable for placement of C1 screw because of anatomic anomalies. There were no spinal cord and vertebral artery and nerve injury after surgery. Follow-up duration was from 18 to 55 months with the average of 29 months. The plant bones all fused and there were no internal fixation rupture and mobility. All the patients showed improvement. CONCLUSIONS: C2 pedicle screw and plate combined with C1 titanium cable could be used to treat atlantoaxial instability in the cases not suitable for placement of C1 screw.

[Role of adenosine triphosphate-sensitive potassium channel in hydrogen sulfide-induced inhibition of high glucoseinduced osteoblast damage].

OBJECTIVE: The aim of this study is to identify the role of adenosine triphosphate-sensitive potassium channel (KATP) in hydrogen sulfide (H2S)-induced inhibition of high glucose (HG)-induced osteoblast damage. METHODS: Osteoblasts from rat mandible were cultured and identified. The osteoblasts were then treated with HG, H2S, KATP channel opener pinacidil (Pia), and KATP channel blocker glibenclamide (Gli). Western blot method was performed to detect the expression of KATP channel protein. CCK8, reverse transcriptase polymerase chain reaction (RT-PCR) , and image analysis were used to determine the effects of H2S-KATP on the proliferation, differentiation, and mineralization of osteoblasts. RESULTS: The expression of KATP channel protein in osteoblasts was significantly decreased under the influence of HG. H2S pretreatment significantly inhibited HG on KATP channel protein down-regulation. Moreover, H2S pretreatment significantly inhibited the effect of HG on the proliferation of osteoblasts, thereby preventing HG-induced inhibition of osteoblasts differentiation and mineralization. Meanwhile, the KATP channel blocker effectively blocked the H2S on osteoblasts and had a protective effect. CONCLUSIONS: Through the KATP channel, H2S inhibited osteoblasts damage induced by HG.

Systematic comparison of biologically active foreign ions-codoped calcium phosphate microparticles on osteogenic differentiation in rat osteoporotic and normal mesenchymal stem cells.

Osteoporosis is a disease characterized by structural deterioration of bone tissue, leading to skeletal fragility with increased fracture risk. Calcium phosphates (CaPs) are widely used in bone tissue engineering strategies as they have similarities to bone apatite except for the absence of trace elements (TEs) in the CaPs. Bioactive glasses (BGs) have also been used successfully in clinic for craniomaxillofacial and dental applications during the last two decades due to their excellent potential for bonding with bone and inducing osteoblastic differentiation. In this study, we evaluated the osteogenic effects of the ionic dissolution products of the quaternary Si-Sr-Zn-Mg-codoped CaP (TEs-CaP) or 45S5 Bioglass® (45S5 BG), both as mixtures and separately, on rat bone marrow-derived mesenchymal stem cells (rOMSCs & rMSCs) from osteoporotic and normal animals, using an MTT test and Alizarin Red S staining. The materials enhanced cell proliferation and osteogenic differentiation, especially the combination of the BG and TEs-CaP. Analysis by quantitative PCR and ELISA indicated that the expression of osteogenic-specific genes and proteins were elevated. These investigations suggest that the TEs-CaP and 45S5 BG operate synergistically to create an extracellular environment that promotes proliferation and terminal osteogenic differentiation of both osteoporotic and normal rMSCs.

[Promotion of Porphyromonas gingivalis to viral disease].

Chronic periodontitis is one of the most common oral diseases in humans, the main recognized pathogenic bac-terium of which is the Porphyromonas gingivalis. Various types of viruses have been detected in periodontal disease in situ, and the joint action of viral and bacterial pathogens infection mechanism are complicated. Porphyromonas gingivalis has the characteristics resulting from the interaction with a variety of bacterium viruses, which may be the reason for chronic perio-dontitis being a protracted disease associated with a variety of systemic diseases. In this paper, we reviewed the relationship between Porphyromonas gingivalis and viral diseases to provide a new idea for the treatment of patients with periodontal disease and viral infections.

[A clinical study on blood pressure changes before and after tooth extraction in 649 elderly patients].

PURPOSE: To investigate the safety of tooth extraction under ECG monitoring in 649 senile patients with hypertension by observing the blood pressure changes during operation. METHODS: The patients were divided into hypertension group and non-hypertension group. ECG monitoring was carried out during extraction. Blood pressure changes were monitored and recorded. The data was statistically analyzed with SPSS 18.0 software package. RESULTS: The patients' blood pressure in the two groups increased as a result of tooth extraction, and the change was more obvious in patients with hypertension. When blood pressure was controlled to normal range, there was no significant difference in blood pressure between the hypertension group and non-hypertension group. The increase of blood pressure of patients taking ß-receptor blockers was minimal. CONCLUSIONS: Preoperative blood pressure control is important for reducing surgical risk in patients with hypertension during ECG monitoring extraction.

[Genetic analysis of 32 microsatellite loci in 13 families of Wuzhishan pig by multiplex PCR and gene scanning technique].

Wuzhishan pig is one of the rare and endangered breeds in china. They have the following characteristics such as :light body weight and small size, early sexually maturity, high meat quality and genetic identification with 6 approximately 8 pares litter size,body weight of born 0.3 approximately 0.4 kg, 15 approximately 16 kg at 6 month old, 35 kg at 2 years old, and so on. They may be used for laboratory utilization, comparative studies on human medical model, embryonic engineering, nutrition metabolism, sensitivity test on virus and bacteria, skin brut and tranfer, removing lipid, teeth and mouth cavity diseases, studies on cardiovascular model and evaluation of new medicine products. The polymorphisms of 32 microsatellites in 13 families of Wuzhishan pig in Hainan were Analysed. Number of alleles in each family was counted, mean heterozygosity and polymorphism Information content(PIC) were calculated. The results showed that number of alleles was 13.66, mean heterozygosity was 0.559 while polymorphism information content was 0.731. This revealed that genetic diversity is abundant in Wuzhishan pig in Hainan. These results have instructional significance for preserving breeds, selection and breeding, development and utilization of Wuzhishan pig in Hainan.

Comparison of Subgingival and Peri-implant Microbiome in Chronic Periodontitis.

OBJECTIVES: To analyse the microbia composition of 10 healthy dental implants and 10 chronic periodontitis patients. METHODS: Subgingival plaque and peri-implant biofilm were sampled at the first molar site before and after implant restoration. The analysis was conducted by 454-prosequencing of bacterial V1 to V3 regions of 16S rDNA. RESULTS: Chronic periodontitis subjects showed greater bacterial diversity compared with implant subjects. The relative abundance of sixteen genera and twelve species differed significantly between implant and chronic periodontitis subjects. The genera Catonella, Desulfovibrio, Mogibacterium, Peptostreptococcus and Propionibacterium were present in higher abundance in chronic periodontitis subjects, while implant subjects had higher proportions of Brevundimonas and Pseudomonas species. CONCLUSIONS: Our results demonstrate that implant restoration changes the oral microbiota. The analysis suggests that periodontal bacteria can remain for a prolonged period of time at non-dental sites, from where they can colonise the peri-implant.

[Effect of oral alloy post and core on magnetic resonance imaging].

OBJECTIVE: This study aims to observe and compare the influences of the casting alloy post and cores on magnetic resonance imaging (MRI). METHODS: Six casting alloy post and sores were fabricated for the experimental groups, and zirconia post and core served as the control. The seven types of post and cores were of the same size and shape. Each post and core was orally fastened to a volunteer and then imaged with sequences of T1-weighted spin echo imaging (SE-T1WI), T2-weighted turbo spin-echo imaging (TSE-T2WI), and diffusion weighted imaging (DWI). RESULTS: Cobalt chromium alloy post and core generated severe artifacts, whereas gold palladium alloy post and core generated no obvious artifacts, and no difference was observed between the zirconia and the gold palladium alloy post and cores (P > 0.05). The pure titanium alloy post and core produced mild artifacts. The post and cores of the titanium, nickel-cadmium, and gold platinum alloys generated moderate artifacts with no significant differences (P > 0.05). CONCLUSION: Different metal post and cores have different influences on MRI. With the exception of that generated by cobalt chromium alloy, the artifact generated by the single-alloy post and core does not influence the image of the normal head and neck.

A novel method for rapid determination of total solid content in viscous liquids by multiple headspace extraction gas chromatography.

This work demonstrates a novel method for rapid determination of total solid content in viscous liquid (polymer-enriched) samples. The method is based multiple headspace extraction gas chromatography (MHE-GC) on a headspace vial at a temperature above boiling point of water. Thus, the trend of water loss from the tested liquid due to evaporation can be followed. With the limited MHE-GC testing (e.g., 5 extractions) and a one-point calibration procedure (i.e., recording the weight difference before and after analysis), the total amount of water in the sample can be determined, from which the total solid contents in the liquid can be calculated. A number of black liquors were analyzed by the new method which yielded results that closely matched those of the reference method; i.e., the results of these two methods differed by no more than 2.3%. Compared with the reference method, the MHE-GC method is much simpler and more practical. Therefore, it is suitable for the rapid determination of the solid content in many polymer-containing liquid samples.

Effect of soft tissue thickness on the morphology of lip in orthodontic treatment / Efecto del grosor del tejido blando en la morfología del labio en el tratamiento de ortodoncia

The aim of this study was to evaluate the effect of soft tissue thickness of upper lip on lip retraction in orthodonticaltreated females and identify the ratio of maxillary incisor retraction to upper lip retraction. Pre- and post-treatment lateral cephalograms of 100 adults were examined to measure the lip thickness in upper lip and establish the classification standard. All subjects were treated with 4 first premolar extractions followed by upper central incisors retraction. Pre- and post-treatment lateral cephalograms of 19 patients were reviewed to determine the changes of the upper lip and incisor positions through landmarks displacement. An independent-samples t test and one-way analysis of variance were performed. The correlations between maxillary incisor retraction and upper lip retraction were explored by the Pearson correlation method. P-values<0.05 were considered statistically significant. The lip thickness of adult male patients was greater than that of adult female patients. The average ratio of maxillary incisor retraction to upper lip repositioning was 1.6:1,1.9:1 and 2.2:1 in the thin lips group, normal lips group and thick lips group, respectively. Gender differences exist in the thickness of upper lip. Horizontal changes of the maxillary incisor showed a significant correlation to horizontal changes of the upper lip (P<0.001).There were negative correlations between the thickness of upper lip and the ratio between change in maxillary incisor protrusion and change in upper lip protrusion.

El objetivo de este estudio fue evaluar el efecto del grosor de los tejidos blandos del labio superior, sobre la retracción del labio en mujeres tratadas con ortodoncia e identificar la proporción de retracción del diente incisivo maxilar con respecto a la retracción del labio superior. Se examinaron cefalogramas laterales, previos y posteriores al tratamiento de 100 adultos, para medir el grosor del labio superior y establecer un estándar de clasificación. Todos los sujetos fueron tratados con 4 extracciones de los primeros premolares seguidas de retracción de los incisivos centrales superiores. Se revisaron los cefalogramas laterales, previos y posteriores al tratamiento de 19 pacientes, para determinar los cambios del labio superior y las posiciones de los incisivos a través del desplazamiento de los puntos de referencia. Se realizó una prueba t de muestras independientes y un análisis de varianza de una vía. Las correlaciones entre la retracción del incisivo maxilar y la retracción del labio superior se exploraron mediante el método de correlación de Pearson. Los valores de p<0,05 fueron considerados estadísticamente significativos. El grosor de los labios de los pacientes adultos masculinos fue mayor que el de las pacientes adultas. La relación promedio de la retracción del incisivo maxilar al reposicionamiento del labio superior fue de 1,6:1,1; 9:1 y 2,2:1 en el grupo de labios delgados, grupo de labios normales y grupo de labios gruesos, respectivamente. Existen diferencias de sexo en el grosor del labio superior. Los cambios horizontales del incisivo maxilar mostraron una correlación significativa con los cambios horizontales del labio superior (P<0,001). Hubo correlaciones negativas entre el grosor del labio superior y la relación entre el cambio en la protuberancia del incisivo maxilar y el cambio en la protrusión del labio superior.