GC Pattern Research Articles

Intron-capture RNA-seq reveals the landscape of intronic RNAs in Arabidopsis

Intronic RNAs have been overlooked for a long time: They are functional, but treated as “junk.” In this work, we designed a new sequencing strategy to investigate intronic RNAs. By using intron-capture RNA-seq, we systematically analyzed the intronic RNAs in Arabidopsis by zooming into the intronic regions an order of magnitude deeper than in previous work. Our key findings include: (1) Intron-capture RNA-seq is a much more efficient approach to analyze intronic RNAs than total RNA-seq and mRNA-seq. (2) We identified three types of intronic RNAs, and found that the GC pattern differs significantly between the introns with and without intronic RNAs. (3) We detected many hidden elements in introns, including circular RNAs, splice junctions, and transcripts that have previously been overlooked. (4) The expression of these intronic RNAs varies during the time course of pathogen infection, which indicates that an unknown mechanism may exist for these RNAs. (5) We also demonstrated that most of intronic RNAs are detectable in both Arabidopsis and rice, suggesting that these non-coding molecules are conserved. Taken together, this work proposes an efficient strategy to analyze intronic RNAs, and provides an unprecedented view of this essential component in biological pathways.

Accuracy of the Different Materials Used to Fabricate a Verification Jig of Implant-Supported Fixed Complete Dental Prostheses: An In Vitro Study

Introduction The passive fit of a full arch implant-supported prosthesis is one of the elements influencing implant success. Achieving the passive fit of a prosthesis requires verification of the master cast before the fabrication of the framework. A verification jig is a common way to verify the implant master cast and ensure the accuracy of the implant impression and produced cast. Different materials can be used to fabricate verification jigs, and each material exhibits different dimensional changes. In this study, we compared the accuracies of verification jig materials by 3D assessment. Materials and methods A type IV stone cast with four implant analogs was constructed and used as a control. Verification jigs were constructed from five different materials, and test casts were made from these jigs and poured using low expansion stone (type IV), resulting in five groups (n=5). All test casts and the control cast were scanned using a lab scanner. The scans of test casts were superimposed on that of the control cast for 3D accuracy assessment. The distortion of the implant analogs was recorded using Geomagic Design X and GeomagicControlX software (3D Systems, Rock Hill, South Carolina, USA). Statistical differences in the 3D accuracies between the five groups were analyzed using the Kruskal-Wallis test. Result The photopolymerizable resin group had a mean value of 23.16 (± 0.88) µm; the composite group had a mean value of 46.72 (± 2.122) µm; the GC pattern group had a mean of 23.51 (± 0.736) µm; the type III stone group had a mean of 19.84 (± 1.017) µm; the type IV stone group had a mean of 18.72 (± 0.819) µm. The Kruskal-Wallis test indicated that there were statistically significant differences between groups 2 (composite), 4 (type III stone), and 5 (type IV stone). Conclusion The most accurate cast was produced by type IV stone, followed by type III stone, photopolymerizable resin, GC pattern, and composite in order of decreasing accuracy. Within the limitations of the study, a material with low distortion and high accuracy is recommended when fabricating verification jigs of implant-supported complete dental prostheses.

Comparison of the Accuracy of Fixture-Level Implant Impression Making with Different Splinting Techniques.

Objectives The impression-taking technique is one of the most critical factors that not only prevents the shrinkage caused by polymerization but also enhances the accuracy of implant impressions. Also, choosing the right time of taking impressions after splinting implants is one of the important criteria that affects the impression-taking technique. Accordingly, the present study aimed to evaluate the accuracy of different splint methods for implant impressions made at different times. Methods In this in vitro study, a two-piece metallic index was prepared, and the patient's jaw was simulated by placing self-cured acrylic resin in the lower part of the index. Then, two holes were made in the acrylic resin at a specific distance from each other, and the analogs were placed in these holes. Splinting of impression copings was carried out with autopolymerized acrylic resin (GC Pattern resin LS, GC America Inc., USA), and an open tray impression approach was performed. Thirty-six casts in three groups (n = 12) were fabricated from the acrylic model. After scanning the casts, the impression accuracy was compared between the three study groups by measuring the distance between the outer portions of the scan bodies screw-retained on implant analogs inside the cast using the Exocad software (2015.07 version). Group 1: splinting impression copings with autopolymerized acrylic resin and impression making immediately after the setting time (4 minutes); group 2: splinting and impression procedure after 17 minutes with splint sectioning and reconnection; group 3: splinting and impression procedure after 24 hours with splint sectioning and reconnection. The data were analyzed using SPSS 17 using the Kruskal–Wallis test. Results The mean distance measured in group 1 was 19.14 ± 0.029 mm, which was significantly lower than the main model. The distances were 19.15 ± 0.039 and 19.159 ± 0.33 mm in groups 2 and 3, respectively. These two groups were not significantly different from the main model. Moreover, the mean distance measured in the three impression techniques was similar. Conclusions There was no significant difference in the measurements between group 2, group 3, and the main model. Therefore, dentists can make an impression after 17 minutes to reduce chair time.

Chemical composition of the essential oil and headspace of Satureja montana L.

Volatile constituents of Satureja montana L. collected from a natural habitat in the southern region of Bosnia and Herzegovina were isolated by steam distillation and headspace sampling. The relative abundance of volatile compounds from the air-dried fragrant plant was analysed by GC-MS using two columns of different polarity. A total of 28 compounds were identified, constituting 93.5% of the essential oil composition. The GC pattern of headspace was different from that prepared by steam distillation. The former consisted of 14 compounds that made up 84.1% of the components identified. Both samples were dominated by oxygenated monoterpenes ranging from 55.2% for headspace of the plant material to 75.5% for the steam-distilled oil. Eleven alcohols represented the most diverse chemical class in the volatile oil (71.8%), as well as seven alcohols detected in the headspace (57.3%). GC-MS analysis of the volatiles indicates that S. montana belongs to linalool chemotype with its relative content of 38.7% for the essential oil and 23.7% for the headspace. With linalool as the most abundant constituent, the other major components were -terpineol (14.7%) in the essential oil, and cis-sabinene hydrate (21.8%) and p-cymene (17.9%) in the headspace sample. The results prove that the combined approach in the extraction of volatile compounds is reliable for the analysis of the aroma of complex herbal samples.

NI-18 INVASIONS OF WHITE MATTER AS A PROGNOSTIC FACTOR IN LOW GRADE GLIOMAS

INTRODUCTIONGliomatosis cerebri (GC), which was characterized by widespread infiltration of the brain involving three lobes, was deleted in the 2016 WHO classification. However, it is known that gliomas with GC growth pattern have a poor prognosis even in low histological grading. In this study, we focused on tumor invasion into white matter fibers. We analyzed the MRI findings focusing on white matter fibers and compared in patients with histologically proven low grade gliomas (LGGs) with GC pattern and localized LGGs.METHODThe patients can be classified into four groups according to the range of tumor invasion in T2-weighted image as follows: group 1, more than 3 lobes (n=6); group 2, 1 or 2 lobes infiltrate the basal ganglia (n=5); group 3, multicentric (n=2) and group 4 (n=12), localized. In reference to the human brain white matter atlas, the infiltration to the major white matter fibers (uncinate fasciculus, genu &splenium of corpus callosum, inferior fronto-occipital fasciculus, superior& inferior longitudinal fasciculus) was examined.RESULTSTwenty-five patients (median 39.5 years) were included in the study. Of these, 20 patients were histologically diagnosed with diffuse astrocytomas, and 5 patients with oligodendrogliomas. The infiltrations into ifo, slf, and ilf of white matter fibers were a poor prognostic factor. The number of infiltrating white matter fibers correlated significantly with the Kaplan-Meier survival curve.CONCLUSIONSThe 2016 WHO classification defines diagnostic entities by combining molecular and histological information and remove GC as a distinct glioma entity. LGGs with GC pattern should be considered to be detected in different types of histologically and molecularly defined gliomas. As the patient numbers analyzed here were small, and larger series reproducing these results would be desirable. MRI findings particularly focusing on infiltration of LGGs into white matter fibers might be important to estimate the prognosis of patients.

Shrinkage characteristics of a novel lower contractile acrylic pattern resin.

Forming models and brazing parts, both of which require high accuracy, are greatly affected the polymerization shrinkage of pattern resin. In 2018, a lower-shrinkage autopolymerizing pattern resin (PRK) was introduced. In this work, we compared the rate of polymerization shrinkage between PRK with that of three autopolymerizing resins -GC Pattern Resin (GPR), Pi-Ku Plast (PIK), and Fixpeed (FIX)- as controls. The shrinkage percentages at 10 min were 7.26±0.88 for PRK, 10.78±2.28 for GPR, 8.03±1.08% for PIK, and 7.46±1.25 for FIX. The shrinkage of PRK was significantly lower than that of GPR. The lower-shrinkage autopolymerizing resin contains some multifunctional monomer and indicated that the amount of monomer was accordingly reduced from the result of polymer size and abundance ratio. Our results suggested that the monomer component and the polymer particle size were factors that contribute to reducing contraction of the resins.

Gene Evolutionary Trajectories and GC Patterns Driven by Recombination in Zea mays.

Recombination occurring during meiosis is critical for creating genetic variation and plays an essential role in plant evolution. In addition to creating novel gene combinations, recombination can affect genome structure through altering GC patterns. In maize (Zea mays) and other grasses, another intriguing GC pattern exists. Maize genes show a bimodal GC content distribution that has been attributed to nucleotide bias in the third, or wobble, position of the codon. Recombination may be an underlying driving force given that recombination sites are often associated with high GC content. Here we explore the relationship between recombination and genomic GC patterns by comparing GC gene content at each of the three codon positions (GC1, GC2, and GC3, collectively termed GCx) to instances of a variable GC-rich motif that underlies double strand break (DSB) hotspots and to meiocyte-specific gene expression. Surprisingly, GCx bimodality in maize cannot be fully explained by the codon wobble hypothesis. High GCx genes show a strong overlap with the DSB hotspot motif, possibly providing a mechanism for the high evolutionary rates seen in these genes. On the other hand, genes that are turned on in meiosis (early prophase I) are biased against both high GCx genes and genes with the DSB hotspot motif, possibly allowing important meiotic genes to avoid DSBs. Our data suggests a strong link between the GC-rich motif underlying DSB hotspots and high GCx genes.

Dimensional stability of two solder index materials.

Objectives:This study aimed to compare the dimensional accuracy of two indexing materials, an acrylic resin (GC pattern resin) and a castable composite (Bredent). The effect of time lapse until investment was also investigated.Materials and Methods:Two standardized brass dies 15 mm apart were prepared and then 20 identical coping-bar assemblies were designed and fabricated by a rapid prototyping device. Each bar was sectioned at the center, and indices were fabricated from an acrylic resin or castable composite (n = 10 per group). The distances between the reference points were measured with a digital microscope at ×80 magnifications at 15 min, 60 min, and 24 h after indexing. Data were statically analyzed using repeated-measure ANOVA (α = 0.05).Results:The distance between the reference points without the coping being joined was considered as the baseline measurement (control group). The mean distance was 19.30 ± 0.04 mm between the reference points where the copings were not joined. When indexed with acrylic resin, the mean ± standard deviation (SD) dimensions were 19.27 ± 0.087 mm (15 min), 19.25 ± 0.09 mm (60 min), and 18.98 ± 0.1 mm (24 h). The mean ± SD dimensions for composite were 19.29 ± 0.087 mm (15 min), 19.28 ± 0.08 mm (60 min), and 19.26 ± 0.08 mm (24 h). All tested groups showed significant differences compared to the control group except when it was indexed with composite and where the distances were measured after 15 and 60 min (P > 0.05).Conclusions:The most accurate indexed-assemblies belonged to castable composite at 15 and 60 min.

Comparison of implant cast accuracy of multiple implant impression technique with different splinting materials: An in vitro study.

Introduction:An accurate and passive fit of implant framework prosthesis, as well as the successful surgical operation is suggested as one of the critical requirements for long-term implant success.Objective:The purpose of this in vitro study was to evaluate the accuracy of the master cast using open tray impression technique with conventional and novel splinting materials.Methodology:A mandibular reference model with four ADIN implants was done. Ten custom trays were fabricated using the light curable resin sheets. Medium body polyether impression material was used. These trays were randomly divided between the two groups, with five trays in each group. Impression techniques were divided into two groups namely: Group A: Direct impression technique with open tray impression copings splinted with autopolymerizing acrylic resin (GC pattern resin). Group B: Direct impression technique with open tray impression copings splinted with Pro-temp TM 4 (bis-GMA) syringable temporization material. Thus, final impressions were made. Total of 10 master casts were fabricated. Evaluation of casts using Dynascope-Vision Engineering, TESA microhite two- dimension and coordinate measuring machine were used.Results:Statistical comparisons were made using ANOVA test and post-hoc test. Same amount of deviation values obtained with resin splinted and bis-GMA splinted impression copings.Conclusion:The master cast obtained by both the splinting material exhibits no difference from the reference model. So bis-GMA can be used, which is easy to handle, less time consuming, less technique sensitive, rigid, and readily available material in clinics.

Comparison of polymerization shrinkage of pattern resins

The dimensional stability, in particular polymerization shrinkage, of pattern resins affects the accuracy of implant prosthesis fabrication. Recently introduced photopolymerizing pattern resins are easy to use, but their shrinkage needs to be determined and compared with traditional autopolymerizing pattern resins. The purpose of the study was to compare the polymerization shrinkage of photopolymerizing pattern resins with autopolymerizing pattern resins. Two autopolymerizing (DuraLay, GC Pattern resin) and 2 photopolymerizing (Primopattern LC Gel, Primopattern LC Paste) pattern resins were tested. The sample size was 10 for each group. Polymerization shrinkage was determined by measuring the change in area dimensions with image analysis. The percentage of volumetric shrinkage was calculated, and the results were statistically analyzed with ANOVA, followed by the Student-Newman-Keuls post hoc test (α=.05). The volumetric shrinkage values (%; mean ±standard deviation) for GC Pattern Resin were 5.72 ±0.89; for DuraLay, 5.07 ±1.36; for Primopattern LC Gel, 5.42 ±1.83; and for Primopattern LC Paste, 7.43 ±0.62. The volumetric shrinkage of the Primopattern LC Paste was significantly higher than that of the other 3 materials. The photopolymerizing pattern resin in gel form (Primopattern LC Gel) had a similar shrinkage value to the autopolymerizing pattern resins (DuraLay and GC Pattern Resin). However, the photopolymerizing pattern resin in paste form (Primopattern LC Paste) shrank significantly more than the other 3 materials tested.

Comparison of Accuracy of Direct Implant Impression Technique using Different Splinting Materials

ABSTRACT Introduction The accuracy of an impression remains critical factor in achieving passive fit of an implant framework. The accuracy of the master cast would depend on the type of impression material, the implant impression technique and accuracy of die material. The different impression techniques advocated in the literature for implant impressions include direct (open tray) and indirect (closed tray) techniques. Direct technique use square impression copings that are picked up in the impressions which were used in this study. Objective To evaluate the accuracy of direct impression made with resin splinted and bis-GMA splinted open-tray impression coping. Thus to compare the accuracy of impressions obtained using different splinting materials. Materials and Methods A wax mandibular reference model was fabricated and four implants were placed in the mandibular anterior region using surveyor and acrylized with clear heat cure acrylic resin using injection molding technique. Spaced primary cast was fabricated with a uniform thickness of space about 2 mm. Ten custom trays were fabricated using the light curable resin sheets. Medium body polyether impression material was used. Pentamix was used to get a uniform mix. These trays were randomly divided among the two groups, with five trays in each group. Impression techniques were divided into two groups namely: Group A - direct impression technique with open tray impression copings splinted with autopolymerizing acrylic resin (GC pattern resin), group B - direct impression technique with open tray impression copings splinted with Protemp TM4 (bis- GMA) syringable temporisation material. Thus, final impressions were made. Total of 10 master casts were fabricated. Evaluation of casts using Dynascope-Vision engineering, Tesa Microhite 2D and coordinate measuring machine were used. Results Statistical comparisons were made using ANOVA test and post-hoc test. Same amount of deviation values obtained with resin splinted and bis-GMA splinted impression copings. The difference in the values might be because of the variation in the rigidity of the materials used. Conclusion Both the splinting material exhibit similar accuracy in impression, so bis-GMA can be used, which is easy to handle, less time consuming, less technique sensitive, rigid and readily available material in clinics, instead of resin splinted material which is technique sensitive, more time consuming and cumbersome. How to cite this article Selvaraj S, Mohan J, Simon P, Dorairaj J. Comparison of Accuracy of Direct Implant Impression Technique using Different Splinting Materials. Int J Prosthodont Restor Dent 2014;4(3):82-89.

Gas Chromatography-Mass Spectrometric Analysis of Forensic Drug Flunitrazepam upon Exposure to UV Irradiation

The environment may affect the forensic drug evidences in crime scene and is able to produce impurities, which contain vital information for tracing their origin of manufacture and can be used to provide link in crime scene investigation. In this work the response of forensic drug flunitrazepam to the UV irradiation was investigated by gas chromatography-mass spectrometry. We found the substantial change in GC pattern involving multiple GC peaks, indicating the complex reaction of degradation in flunitrazepam upon UV irradiation. GCMS analysis identified one of the GC components to be amino-flunitrazepam. The new GC peaks and the GC pattern change may serve as “chemical signatures” of flunitrazepam. Such information may promote the identification of the forensic drug flunitrazepam as a “chemical fingerprint” in forensic sciences.

P53 and p21waf1— Expression by Immunohistochemistry in Diffuse Large B-Cell Lymphoma Has a Strong and Independent Impact on Survival of Patients with Germinal Center Phenotype.

Over-expression of P53-related protein detected by immunohistochemistry (IHC) and absence of p21waf1— expression, the main downstream target following P53 activation, are useful surrogate markers in identifying diffuse large B-cell lymphoma (DLBCL) patients with mutated P53-gene. Following recent studies on gene expression, tissue micro-array technology has been shown to represent a reliable technique in discriminating DLBCL with germinal center B-cell like (GC), or post- germinal center (non-GC) origin.We analyzed 80 consecutive patients with de-novo DLBCL, homogeneously treated with cure-intent (CHOP-like regimens +/− Rituximab) in a single Institution, for expression of p53/p21waf1—, with regard to the expression of GC (CD10+, bcl-6+/mum-1−/CD138−), and post-germinal center (CD10−, mum-1+, CD138+) IHC markers. Cases with 50% or more p53-positive neoplastic cells were defined as p53+++. All patients were provided with complete clinical information. Median age of our patients was 50 years, AAS was III or IV in half of patients, IPI was high or int/high in 36%. Median follow-up for survivors was 77 months. A p53+++/p21waf1— phenotype (corresponding to loss of function of the P53-gene) was detected in 19 of 80 patients (23%), while a GC phenotype characterized 42 patients (52%). Patients with P53+++/p21waf1— phenotype were more frequently resistant to induction therapies (p<0.0001) and had a significantly lower 5-year Progression Free Survival (PFS, 27% vs 48%, p=0.01). Patients with GC phenotype were associated with a better 5-year PFS than non-GC patients (57% vs 26%, p=0.02). When analysis was restricted to the 42 patients with GC phenotype, p53+++/p21waf1— phenotype could discriminate 28% of patients with PFS of 26% vs 68% of patients with GC pattern and other p53/p21waf1— phenotypes (p=0.005). In contrast, the outcome of patients with a non-GC phenotype was not modified by p53/ p21waf1— expression. At multivariate analysis, p53+++/p21waf1— phenotype, non-GC phenotype, and high IPI resulted the strongest independent factors in worsening PFS of our patients. Combining such adverse prognostic factors we could identify 60% of patients with an extremely poor prognosis (5-year PFS of 28%).Our results strongly point to the usefulness of a combined molecular and clinical approach for prognostic considerations in DLBCL, and should be validated in larger series.

Statistical properties of nucleotides in human chromosomes 21 and 22

In this paper the statistical properties of nucleotides in human chromosomes 21 and 22 are investigated. The n -tuple Zipf analysis with n = 3, 4, 5, 6, and 7 is used in our investigation. It is found that the most common n -tuples are those which consist only of adenine (A) and thymine (T), and the rarest n -tuples are those in which GC or CG pattern appears twice. With the n -tuples become more and more frequent, the double GC or CG pattern becomes a single GC or CG pattern. The percentage of four nucleotides in the rarest ten and the most common ten n -tuples are also considered in human chromosomes 21 and 22, and different behaviors are found in the percentage of four nucleotides. Frequency of appearance of n -tuple f ( r ) as a function of rank r is also examined. We find the n -tuple Zipf plot shows a power-law behavior for r < 4 n −1 and a rapid decrease for r > 4 n −1 . In order to explore the interior statistical properties of human chromosomes 21 and 22 in detail, we divide the chromosome sequence into some moving windows and we discuss the percentage of ξη ( ξ , η = A, C, G, T) pair in those moving windows. In some particular regions, there are some obvious changes in the percentage of ξη pair, and there maybe exist functional differences. The normalized number of repeats N 0 ( l ) can be described by a power law: N 0 ( l ) ∼ l − μ . The distance distributions P 0 ( S ) between two nucleotides in human chromosomes 21 and 22 are also discussed. A two-order polynomial fit exists in those distance distributions: log P 0 ( S ) = a + bS + cS 2 , and it is quite different from the random sequence.

The effect of time lapse on the accuracy of two acrylic resins used to assemble an implant framework for soldering

Statement of problem There are insufficient data on the accuracy of resin indexing materials for the assembly of implant prostheses in vivo. Material and methods This in vitro study assessed the fit of an implant framework with the use of 2 common acrylic resins. Purpose A standardized type IV gold alloy cast framework with 3 stainless steel implant replicas secured to 3 premachined gold cylinders placed 200 mm apart using a parallelometer was fabricated on a flat type IV stone model. Wax was placed around the center of each bar section, and a silicone matrix was fabricated to enable the same quantity of material to be used for each assembly. Each bar was sectioned at the center of the matrix, and indices (n=20) were fabricated from Duralay and GC Pattern acrylic resins. The materials were allowed to polymerize for 15 minutes before the assemblies were removed from the model. Frameworks were visually assessed for fit after an additional 15 minutes, after 2 hours, and after 24 hours, using the Sheffield 1-screw test. Observational outcomes are presented indicating visually perceived fit relative to the type of indexing resin. Results Both indexing materials were judged to be visually accurate at the 15-minute time interval only. Conclusion Within the limitations of this in vitro study, both resin-indexed implant assemblies were judged visually accurate for fit 15 minutes after polymerization but not at subsequent test intervals.

Verification jig for implant-supported prostheses: A comparison of standard impressions with verification jigs made of different materials

Statement of Problem. Implant verification jigs are routinely used during the fabrication of implant-supported prostheses. The dimensional accuracy of these jigs is unknown. Purpose. The purposes of this study were to (1) compare the dimensional accuracy of verification jigs with that of conventional impression procedures and (2) measure the dimensional accuracy of 3 resin materials used to fabricate verification jigs. Material and Methods. Thirty verification jigs and 20 impressions were made of 3 externally hexed Steri-Oss implants in a master stone base according to the following groups (n = 10 per group): (Group 1) Jig: GC pattern resin; (Group 2) Jig: Duralay resin; (Group 3) Jig: Triad gel resin; (Group 4) Impression: closed-tray impression copings; and (Group 5) Impression: open-tray impression copings. A stone base was fabricated for each experimental jig and impression. Master stone base and experimental stone bases were measured with the following methods: X and Y coordinates of each implant center were obtained with a traveling microscope by averaging the X and Y coordinates of the implant external hex corners. The origins of the coordinates during measurement of each base were arbitrary. Distances between implant center points were calculated by use of the Pythagorean theorem. Vertical measurements (Z-plane) were obtained with a digital caliper at the 2 terminal-implant locations. Interimplant distances and vertical measurements were subtracted from those of the master base, and the resultant distortion values were analyzed with analysis of variance and Tukey Studentized range tests. Statistical significance was set at P<.05. Results. Verification jigs were not significantly more accurate than standard impression procedures. Open-tray impressions showed a significantly greater vertical distortion (Z-R location: 262 ± 158 μm; P=.0001; Z-L location 333 ± 189; P=.0001) compared with the other groups. Triad gel jigs showed a significantly greater distortion in one interimplant distance (C-L) than closed-tray impressions (P=.04), whereas Duralay jigs exhibited significant greater distortion than closed-tray and open-tray impressions in the interimplant distance R-C (P=.006). Although not significantly different from other groups, the closed-tray group showed the lowest mean distortion values in all measurements. Conclusion. Within the limitations of this study, the accuracy provided by verification jigs was not significantly superior to standard impression procedures. The results suggest that jig fabrication does not improve the dimensional accuracy of stone casts. Open-tray impressions showed a significantly greater inaccuracy in the vertical plane. (J Prosthet Dent 2002;88:329-36.)

Technique to help verify the accuracy of a stone cast for fabrication of a multiple-unit fixed prosthesis

J Prosthet Dent 2002;87:462-3.

Identification of plant and animal glues in museum objects by GC-MS, after catalytic hydrolysis of the proteins by the use of a cation exchanger, with simultaneous separation from the carbohydrates.

A method is described which enables the group-separation of proteinaceous binding media from vegetable glues (carbohydrates), and simultaneous hydrolysis of the proteins in mixtures of both. The mixtures of the binders are suspended in aqueous-ethanolic solvent with the H+ form of a strong cation exchanger and treated at elevated temperature in sealed vials. The polypeptides are cleaved by H+-catalysed hydrolysis. On abstraction the amino acids are transformed into the ammonium ions by the protons, and the cations are adsorbed by the exchanger resin. The amino acids are removed from solution in this way, thus suppressing interfering reactions with other binders, e.g. humin formation with carbohydrates. Clear and colourless solutions were obtained with all mixtures of vegetable and animal glues. Two fractions can be obtained after separation of the solid resin from the liquid supernatant - the resin fraction with the adsorbed amino acids, and the aqueous-ethanolic solution with the carbohydrates. In each of these fractions the two classes of binder can be identified separately by GC-MS; this avoids the occurrence of unresolved GC peaks and superimposed mass spectra. The method has been used to identify the binder found between fabric layers of a Burgundian liturgical vestment of the Order of the Golden Fleece from the first half of the 15th century, the Cope of the Virgin Mary. With the aid of the GC pattern obtained, and the mass spectra of the main peaks, which were identified as glucopyranose anomers, the binding medium was identified as starch.

矯正治療中において下顎を中心位に位置づけるための一考察

R. H. Roth and others have incorporated mandibular function analysis using C.P.I. (Condylar Position Indicator) and Axi-Path Recorder as part of orthodontic diagnosis to achieve the treatment goal of establishing centric occlusion with the condyles seated in centric relation. Their approach is to stabilize the mandibular position with a splint prior to orthodontic treatment in patients with unstable mandibular positions due to Temporo-Mandibular Disorder, major CO-CR discrepancy based on C.P.I. data, or facial asymmetry. The treatment procedures are simplified by utilizing the Straight Wire Appliance or SWA with necessary anatomical information built into the brackets, which are directly bonded to tooth surfaces. This comprehensive system integrating all the steps from diagnosis to treatment has improved the accuracy, reliability and simplicity of orthodontic treatment, contributing greatly to the advancement of modern orthodontics.However, the loss of mandibular stability during orthodontic treatment is unavoidable due to difficulty of wearing a splint with an orthodontic appliance. This paper introduces the mini occlusal splint developed by the authors to compensate for this shortcoming.The patient had no midline deviation initially. The C. P. I. data showed no discrepancy. There was no difference in the amount of cuspid overjet between the right and left sides. Space closure was accomplished equally on both sides. However, the midline deviation was noticed with a difference in the amount of cuspid overjet between the two sides at the time of space closure or 6 months after the beginning of orthodontic treatment. The midline deviation increased further 9 months into treatment. The most probable cause was “mandibular displacement.” However, the patient was in the midst of maxillary anterior retraction, making it difficult to wear a regular splint. The mini occlusal splints were bonded onto the occlusal surfaces with an adhesive resin so that a maximum number of teeth could come into equal occlusal contact in CR. The mandibular position was stabilized and the midline deviation was eliminated approximately 3 months after the placement of the occlusal splints.1. GC pattern resin is mixed. Pour in a small amount of water and mix to the consistency of a dough.2. Take an anterior bite with the resin. Trim the resin to leave shallow indentations of incisal edges of the lower anterior teeth. Replace it in the mouth to check its reproducibility.3. Take posterior bites with a quick-cure resin. Mark an outline of each splint and the tooth number on the upper side of the posterior bite and lower cusp tips on the bottom side with an indelible pen. Trim the resin to leave only cusp tip indentations. Grind each splint along the recorded outline.4. Bond the splints to the occlusal surfaces of the upper molars.1) It is very important to make a differential diagnosis to determine if the problem is skeletal or not. For this purpose, it is necessary to achieve a stable mandibular position prior to orthodontic treatment with a centric splint.2) This case effectively demonstrates the effectiveness of the mini occlusal splints when midline deviation is caused by mandibular displacement.3) In our practice, 30 patients have developed TMD symptoms during orthodontic treatment. The symptoms were eliminated in 28 patients of these patients.

The Production of Pelargonium graveolens Oil by Shoot and Plant Tissue Culture

ABSTRACT The production of essential oil from Pelargonium graveolens by plant tissue culture was investigated. Since the essential oil could not be obtained by callus culture, shoot culture was investigated. Sterile plants were induced from intact plants by using solid medium with appropriate hormones. Young shoots which also were obtained from sterile plants, were well cultivated in liquid medium by a method of agitating with air. The odor of the essential oil obtained from cultured shoots was found to be similar to that of the natural essential oil. Furthermore, the GC pattern of the volatile compounds in the essential oil from cultured shoots was similar to that of natural essential oil. The content of citronellol, a major constituent of natural Pelargonium leaf oil, was slightly less in the cultured shoots than in the intact plant.