SAF System Research Articles

Vlerësimi i aftësisë obturuese të pastave me bazë të bioqeramikës në mbushjen e kanalit të rrënjës së dhëmbit pas përpunimi me SAF sistem - studim in vitro

The aim of this study was to determine the penetration of MTA Fillapex paste (Angelus, Londrina, PR, Brazil) into the dentin tubules in root canals obturated with lateral con- densation gutta-percha technique in the presence or ab- sence of smear layer. For this in vitro study, 30 human man- dibular premolars extracted for periodontological reasons were tested. After removing the crown at the enamel-ce- ment junction, and after root canal access the preparation was done with Self-adjusting File instruments (ReDent-No- va, Ra’anana, Israel). The irrigation was done with sodi- um hypochlorite 2.6% (1st group), as well as with sodium hypochlorite 2.6% and EDTA (2nd group). The root canal obturation paste used for these two experimental groups was MTA Fillapex paste in combination with gutta-percha lateral condensation method. After this the samples were sectioned at a distance of 4, 8 and 12 mm from the apex. Penetration of root canal paste into dentinal tubuli was determined by confocal laser microscopy. The obtained re- sults reported a higher penetration of pasts in the dentine tubuli in coronal and middle thirds, while regarding the re- moval of the smear layer, it was reported that its removal allows greater depth of filling in the dentinal tubuli after preparation with SAF system, as well as obturated with the gutta-percha lateral condensation technique.

The effect of experimental conditions in root dentin microcracks detection by micro-computed tomography

The aim of the study was to assess the effect of different experimental conditions on registration of microcracks by means of micro-computed tomography. Twenty roots of permanent lower incisors were instrumented with SAF system, filled with a single-cone technique and retreated with the Pro Taper Universal Retreatment system. Each sample was measured in dry, water, and moist conditions. The dry scanning was done after drying of the roots for a period of 4 h in ambient conditions followed by a second observation in wet environment after 48 h of rehydrating in distilled water. A time scan was performed to measure the dentin shrinkage while drying the samples in the tomograph’s device compartment. All roots underwent complex inhomogeneous shrinkage and deformation due to the internal stress upon dehydration. This deformation opened the existing cracks to an extent above the current resolution of today’s laboratory computed tomography scanners. Contrary, rehydration of the dentin reversed the deformation thus closing some of the cracks below the computed tomography resolution making them undetectable. The first dehydration of dentin may be a source of cracks initiation itself.

Machine‐Learning Characterization of Tectonic, Hydrological and Anthropogenic Sources of Active Ground Deformation in California

AbstractTectonic, hydrological and industrial processes coexist in the dynamic natural environments. However, our knowledge of ground deformation associated with tectonic, hydrological and anthropogenic processes and their interactions remains limited. California represents a natural laboratory that hosts the San Andreas fault system, Central Valley and other aquifer systems, and extensive human extraction of natural resources. The attendant multi‐scale ground deformation that has been mapped using Copernicus Sentinel‐1 Synthetic Aperture Radar (SAR)‐satellite constellation from four ascending and five descending tracks during 2015–2019. We consider the secular horizontal surface velocities and strain rates, constrained from GNSS measurements and tectonic models, as proxies for tectonic processes, and seasonal displacement amplitudes from interferometric SAR (InSAR) time series as proxies for hydrological processes. We synergize 23 types of multidisciplinary datasets, including ground deformation, sedimentary basins, precipitation, soil moisture, topography, and hydrocarbon production fields, using a machine learning algorithm–random forest, and we succeed in predicting 86%–95% of the representative data sets. High strain rates along the SAF system mainly occur in areas with a low‐to‐moderate vegetation fraction (∼0.3), suggesting a correlation of rough/high‐relief coastal range morphology and topography with the active faulting, seasonal and orographic rainfall, and vegetation growth. Linear discontinuities in the long‐term, seasonal amplitude and phase of the surface displacement fields coincide with some fault strands, the boundary zone between the sediment‐fill Central Valley and bedrock‐dominated Sierra Nevada, and the margins of the inelastically deforming aquifer in the San Joaquin Valley, suggesting groundwater flow interruptions, contrasting elastic properties, and heterogeneous hydrological units.

Evaluation of microcrack formation during root canal preparation using hand, rotary files and self-adjusting file in primary teeth: An in vitro study.

Background. Pediatric endodontics is a field with constant evolution, resulting in the shifting of paradigms from the use of conventional hand files to rotary files for biomechanical preparation in primary teeth. Biomechanical preparation plays a crucial role in the success of root canal treatment. Primary teeth need special attention since they differ from permanent teeth in root canal morphology. Cleaning and shaping of the canals damage the root dentin, leading to dentinal cracks. Newer techniques for root canal preparation, including Ni-Ti rotary files and SAF system, have been developed for use in pediatric endodontics to overcome the drawbacks of conventional methods. The present study compared dentinal defects formed by rotary systems in primary teeth.Methods. Eighty primary teeth were included. The teeth were decoronated with a diamond disc. All the roots were inspected for any pre-existing cracks or craze lines under transmitted light under a stereomicroscope. The specimens were then divided into four groups (n=20): group 1: control, group 2: hand files (HF), group 3: ProTaper files, and group IV: SAF files. The samples were instrumented according to the group they were assigned to. Results. The HF and SAF groups exhibited fewer microcracks. Dentinal microcracks were observed in roots prepared with rotary ProTaper files. There were significant differences between HF/SAF and rotary files (P <0.05). Conclusion. Stainless steel hand K-files and SAF instruments resulted in fewer dentinal damage than the ProTaper Universal files. SAF exhibited satisfactory results with minimal or no crack formation.

Seed germination and performance of sunflower seedlings submitted to produced water

ABSTRACT The use of produced water becomes an option in the irrigation of non-food crops with potential for biofuel production. However, its effects on different stages of plant development and mainly on seed germination should be known. The study was conducted to evaluate the performance of sunflower seedlings subjected to different types of produced water. An experimental design in a factorial scheme was adopted to evaluate 3 cultivars (Catissol 01, Embrapa 122 and IAC Iaramã) and 6 types of water (distilled water - control, public-supply water, water resulting from the water and oil separation process - WOS, filtration in sand filter - SAF, filtration in sand + charcoal filter - SCF, and filtration in sand + osmosis filter - SOF). In addition, the substrate was moistened with polyethylene glycol (PEG) solutions, simulating the osmotic potentials of the evaluated waters, and a sensitivity test was conducted with lettuce seeds under conditions similar to those adopted for sunflower. The cv. Catissol showed higher percentages of germination and vigor of seedlings, regardless of the water used. There was a trend of reduction in germination and vigor of seedlings with the use of produced water treated with the WOS, SAF and SCF systems. All water potentials simulated by PEG solutions reduced the germination and vigor of lettuce seeds, and the effect was more pronounced for the WOS system. SOF was the only one capable of making the produced water non-toxic to sunflower seeds and lettuce seedlings.

Micro CT Analysis of Hard Tissue Debris Accumulation Created by SAF vs. ProTaper systems

Background and objectives: Hard tissue debris is deposited routinely during root canal system instrumentation. A new instrument had been marketed with the aim of optimum shaping of all parts of the canal system, however, no information present about the amount of debris removal compared to conventional rotary system. This study investigated the amount of debris accumulated when the canal instrumented by SAF compared with ProTaper by using high resolution computed tomography (micro CT). Methods: Twenty extracted single canalled teeth were utilized for this study; and randomly divided into 2 groups. In the first group, the root canals were prepared by using protaper rotary system till F2 and the root canal irrigated with 1ml of normal saline after each instrument. The root canals in the second group were prepared using SAF for 4min, with continuous irrigation (normal saline). After rescanning, the percentage value of total canal volume filled with hard tissue debris was calculated. Results: For protaper instrumentation, a mean of 0.35% of the total canal system volume was filled with hard-tissue debris which was lesser than that of SAF system where a mean of 0.42 % vol. was obtained. However, there was non-significant difference between them (p=0.218) with in favor of the SAF system. Conclusion: Root canal preparation with SAF-system resulted in more and effective hard tissue debris accumulation compared with protaper rotary files.

Histopathology, grading and staging of nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the liver disease associated with obesity, diabetes and the metabolic syndrome. Although steatosis is a key histological feature, liver biopsies of patients with NAFLD can show a wide range of other findings, including portal and lobular inflammation, ballooning and apoptotic hepatocellular injury, Mallory-Denk bodies, megamitochondria and fibrosis. Nonalcoholic steatohepatitis (NASH) is a progressive subtype of NAFLD first defined by analogy to alcoholic hepatitis. The characteristic finding in NASH is ballooning hepatocellular injury. The fibrosis pattern is distinctive, with perisinusoidal fibrosis around the central veins being the first manifestation of fibrosis. Young children may have an alternate pattern of progressive NAFLD characterized by a zone 1 distribution of steatosis, inflammation and fibrosis. Several grading and staging systems exist for use in natural history studies and clinical trials, each with some advantages and disadvantages. These include the Brunt system, the NASH CRN system and the SAF system. Each of these systems has been applied to clinical studies permitting correlation of laboratory and demographic observations with histological findings.

Effect of ProTaper Gold, Self-Adjusting File, and XP-endo Shaper Instruments on Dentinal Microcrack Formation: A Micro–computed Tomographic Study

IntroductionThe aim of the present study was to evaluate the frequency of dentinal microcracks observed after root canal preparation with ProTaper Universal (PTU; Dentsply Tulsa Dental Specialties, Tulsa, OK), ProTaper Gold (PTG; Dentsply Tulsa Dental Specialties), Self-Adjusting File (SAF; ReDent Nova, Ra'anana, Israel), and XP-endo Shaper (XP; FKG Dentaire, La Chaux-de-Fonds, Switzerland) instruments using micro–computed tomographic (CT) analysis. MethodsForty extracted human mandibular premolars having single-canal and straight root were randomly assigned to 4 experimental groups (n = 10) according to the different nickel-titanium systems used for root canal preparation: PTU, PTG, SAF, and XP. In the SAF and XP groups, the canals were first prepared with a K-file until #25 at the working length, and then the SAF or XP files were used. The specimens were scanned using high-resolution micro–computed tomographic imaging before and after root canal preparation. Afterward, preoperative and postoperative cross-sectional images of the teeth were screened to identify the presence of dentinal defects. For each group, the number of microcracks was determined as a percentage rate. The McNemar test was used to determine significant differences before and after instrumentation. The level of significance was set at P ≤ .05. ResultsThe PTU system significantly increased the percentage rate of microcracks compared with preoperative specimens (P < .05). No new dentinal microcracks were observed in the PTG, SAF, or XP groups. ConclusionsRoot canal preparations with the PTG, SAF, and XP systems did not induce the formation of new dentinal microcracks on straight root canals of mandibular premolars.

Apical extrusion of debris in four different endodontic instrumentation systems: A meta-analysis.

Background:All endodontic instrumentation systems tested so far, promote apical extrusion of debris, which is one of the main causes of postoperative pain, flare ups, and delayed healing.Objectives:Of this meta-analysis was to collect and analyze in vitro studies quantifying apically extruded debris while using Hand ProTaper (manual), ProTaper Universal (rotary), Wave One (reciprocating), and self-adjusting file (SAF; vibratory) endodontic instrumentation systems and to determine methods which produced lesser extrusion of debris apically.Methodology:An extensive electronic database search was done in PubMed, Scopus, Cochrane, LILACS, and Google Scholar from inception until February 2016 using the key terms “Apical Debris Extrusion, extruded material, and manual/rotary/reciprocating/SAF systems.” A systematic search strategy was followed to extract 12 potential articles from a total of 1352 articles. The overall effect size was calculated from the raw mean difference of weight of apically extruded debris.Results:Statistically significant difference was seen in the following comparisons: SAF < Wave One, SAF < Rotary ProTaper.Conclusions:Apical extrusion of debris was invariably present in all the instrumentation systems analyzed. SAF system seemed to be periapical tissue friendly as it caused reduced apical extrusion compared to Rotary ProTaper and Wave One.

Supplementary Steps for Removing Hard Tissue Debris from Isthmus-containing Canal Systems

IntroductionThe purpose of this ex vivo study was to evaluate the percentage reduction of accumulated hard tissue debris (AHTD) in the mesial root canal system of mandibular molars under different final irrigation regimens by means of micro–computed tomographic imaging. MethodsSixty curved mesial roots of mandibular molars with 2 independent canals joint apically by an isthmus (Vertucci type II) were selected. Specimens were scanned at a resolution of 12.5 μm, anatomically matched, and distributed into 3 groups (n = 20) according to the preparation protocol: Self-Adjusting File (SAF; ReDent Nova, Ra'anana, Israel), Reciproc (VDW GmbH, Munich, Germany), and Revo-S (Micro-Mega, Besançon, France) systems. Then, each group was subdivided into 2 subgroups (n = 10) according to the final irrigation protocol with the SAF or EndoVac system (Discus Dental, Culver City, CA). The percentage volume and percentage reduction of AHTD after root canal preparation and final irrigation protocols were statistically compared using 1-way analysis of variance, the paired sample and the independent Student's t tests. The level of significance was set at 5%. ResultsWithin groups, the mean percentage volume was significantly reduced after the final irrigation procedures in either the SAF (from 1.52%–1.78% to 1.01%–1.20%) or EndoVac (from 2.11%–2.23% to 1.31%–1.52%) subgroups (P < .05). In the experimental groups, the mean percentage reduction of AHTD ranged from 29.15%–39.90% after the irrigation protocols, with no statistical difference between groups (P > .05). ConclusionsNone of the irrigation approaches succeeded in rendering the mesial root canal system free of AHTD. A similar percentage reduction of AHTD was achieved after final irrigation protocols using either the SAF or EndoVac system.

Effect of finishing instrumentation using NiTi hand files on volume, surface area and uninstrumented surfaces in C‐shaped root canal systems

To assess the effect of 90°-oscillatory instrumentation with hand files on several morphological parameters (volume, surface area and uninstrumented surface) in C-shaped root canals after instrumentation using a single-file reciprocation system (Reciproc; VDW, Munich, Germany) and a Self-Adjusting File System (SAF; ReDent Nova, Ra'anana, Israel). Twenty mandibular second molars with C-shaped canals and C1 canal configurations were divided into two groups (n=10) and instrumented with Reciproc and SAF instruments. A size 30 NiTi hand K-file attached to a 90°-oscillatory motion handpiece was used as final instrumentation in both groups. The specimens were scanned using micro-computed tomography after all procedures. Volume, surface area increase and uninstrumented root canal surface were analysed using CTAn software (Bruker-microCT, Kontich, Belgium). Also, the uninstrumented root canal surface was calculated for each canal third. All values were compared between groups using the Mann-Whitney test and within groups using the Wilcoxon's signed-rank test. Instrumentation with Reciproc significantly increased canal volume compared with instrumentation with SAF. Additionally, the canal volumes were significantly increased after 90°-oscillatory instrumentation (between and within group comparison; (P<0.05)). Regarding the increase in surface area after all instrumentation protocols, statistical analysis only revealed significant differences in the within groups comparison (P<0.05). Reciproc and SAF instrumentation yielded an uninstrumented root canal surface of 28% and 34%, respectively, which was not significantly different (P>0.05). Final oscillatory instrumentation significantly reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% (SAF; P<0.05). The apical and middle thirds exhibited larger uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation (P<0.05). The Reciproc and SAF system were associated with similar morphological parameters after instrumentation of mandibular second molars with C-shaped canals except for a higher canal volume increase in the Reciproc group compared to the SAF. Furthermore, the final use of 90°-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation.

Apical debris extrusion associated with oval shaped canals: a comparative study of WaveOne vs Self-Adjusting File.

The aim was to evaluate ex vivo apical debris extrusion associated with WaveOne and Self-Adjusting File instruments when used in oval canals. Twenty-four extracted human mandibular premolars with oval-shaped canals were assigned in two equal groups. Following coronal cavity preparation, a glide path was created. Group A was subjected to canal preparation using a WaveOne primary file, which was used along with syringe and needle irrigation and 10mL of 2.4% NaOCl solution, followed by flushing with 10mL of 17% EDTA solution, activation with EndoActivator for 1min and final flushing with 10mL of 2.4% NaOCl solution, and activation for 30s. Group B, the SAF system was used with continuous simultaneous irrigation, provided by the system's pump. The irrigant was supplied at 5mL/min, alternating every minute between 2.4% NaOCl solution and 17% EDTA solution, over a total of 4min followed by final flushing with 10mL of 2.4% NaOCl solution. Extruded apical debris from each root canal was collected into a preweighed glass vial and dried. The mean weight of the debris from each group was assessed and analyzed statistically. Both systems resulted in apical debris extrusion. The WaveOne system was associated with a statistically significant greater mean mass of apically extruded debris (2.18 ± 0.44mg) than the SAF system (0.49 ± 0.33mg, permutation-based Wilcoxon test, p < 0.001). Both WaveOne and the SAF systems were associated with apical debris extrusion. The amount of debris extruded by the WaveOne system was 4.4 times greater than that extruded by the SAF system. The results of the present ex vivo comparative study cannot be directly applied to the clinical situation. Difference between both groups remains completely unclear; maybe the amount of extrusion is harmless in both groups or similarly deleterious for the periradicular tissues in both groups or may be dose-related to the amount of the extruded material.

Incidencia de sistemas agroforestales con Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg. sobre propiedades físicas de suelos de lomerío en el departamento de Caquetá, Colombia

En los municipios Belén de los Andaquies, Florencia y El Doncello (departamento de Caquetá, Colombia), se colectaron muestras de suelo en lomerío bajo cinco tipos de cobertura (Bosque secundario, Arreglo Agroforestal &lt;em&gt;H. brasiliensis&lt;/em&gt; Muell asociado con frutales y/o frutales, Arreglo Agroforestal con H. brasiliensis Muell y rastrojo, H. brasiliensis Muell en monocultivo y Pastura nativa), con el fin de determinar la incidencia que tienen los sistemas agroforestales con Hevea brasiliensis sobre las propiedades físicas de los suelos. Se encontró que el comportamiento de las variables profundidad del horizonte A, compactación, densidad real y humedad gravimétrica es similar en suelos bajo monocultivo de H. brasiliensis y bajo pastura nativa. El efecto positivo de la especie H. brasiliensis en sistemas agroforestales con frutales y con rastrojos se evidenció en las variables profundidad del horizonte A, densidad aparente, compactación y porosidad total, las cuales se comportaron en forma similar a las de suelos bajo bosque secundario. En general se observa la incidencia de los arreglos agroforestales sobre la modificación de variables físicas del suelo en el piedemonte amazónico.

Micro CT Analysis of Amount of Dentin Removal Created by SAF vs. ProTaper Systems

Micro CT Analysis of Amount of Dentin Removal Created by SAF vs. ProTaper Systems

Composition, Alteration, and Texture of Fault-Related Rocks from Safod Core and Surface Outcrop Analogs: Evidence for Deformation Processes and Fluid-Rock Interactions

We examine the fine-scale variations in mineralogical composition, geochemical alteration, and texture of the fault-related rocks from the Phase 3 whole-rock core sampled between 3,187.4 and 3,301.4 m measured depth within the San Andreas Fault Observatory at Depth (SAFOD) borehole near Parkfield, California. This work provides insight into the physical and chemical properties, structural architecture, and fluid-rock interactions associated with the actively deforming traces of the San Andreas Fault zone at depth. Exhumed outcrops within the SAF system comprised of serpentinite-bearing protolith are examined for comparison at San Simeon, Goat Rock State Park, and Nelson Creek, California. In the Phase 3 SAFOD drillcore samples, the fault-related rocks consist of multiple juxtaposed lenses of sheared, foliated siltstone and shale with block-in-matrix fabric, black cataclasite to ultracataclasite, and sheared serpentinite-bearing, finely foliated fault gouge. Meters-wide zones of sheared rock and fault gouge correlate to the sites of active borehole casing deformation and are characterized by scaly clay fabric with multiple discrete slip surfaces or anastomosing shear zones that surround conglobulated or rounded clasts of compacted clay and/or serpentinite. The fine gouge matrix is composed of Mg-rich clays and serpentine minerals (saponite ± palygorskite, and lizardite ± chrysotile). Whole-rock geochemistry data show increases in Fe-, Mg-, Ni-, and Cr-oxides and hydroxides, Fe-sulfides, and C-rich material, with a total organic content of >1 % locally in the fault-related rocks. The faults sampled in the field are composed of meters-thick zones of cohesive to non-cohesive, serpentinite-bearing foliated clay gouge and black fine-grained fault rock derived from sheared Franciscan Formation or serpentinized Coast Range Ophiolite. X-ray diffraction of outcrop samples shows that the foliated clay gouge is composed primarily of saponite and serpentinite, with localized increases in Ni- and Cr-oxides and C-rich material over several meters. Mesoscopic and microscopic textures and deformation mechanisms interpreted from the outcrop sites are remarkably similar to those observed in the SAFOD core. Micro-scale to meso-scale fabrics observed in the SAFOD core exhibit textural characteristics that are common in deformed serpentinites and are often attributed to aseismic deformation with episodic seismic slip. The mineralogy and whole-rock geochemistry results indicate that the fault zone experienced transient fluid–rock interactions with fluids of varying chemical composition, including evidence for highly reducing, hydrocarbon-bearing fluids.

Assessment of Apically Extruded Debris Produced by the Self-Adjusting File System

IntroductionThis study was designed to quantitatively evaluate the amount of apically extruded debris by the Self-Adjusting-File system (SAF; ReDent-Nova, Ra’anana, Israel). Hand and rotary instruments were used as references for comparison. MethodsSixty mesial roots of mandibular molars were randomly assigned to 3 groups (n = 20). The root canals were instrumented with hand files using a crown-down technique. The ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) and SAF systems were used according to the manufacturers' instructions. Sodium hypochlorite was used as an irrigant, and the apically extruded debris was collected in preweighted glass vials and dried afterward. The mean weight of debris was assessed with a microbalance and statistically analyzed using 1-way analysis of variance and the post hoc Tukey multiple comparison test. ResultsHand file instrumentation produced significantly more debris compared with the ProTaper and SAF systems (P < .05). The ProTaper system produced significantly more debris compared with the SAF system (P < .05). ConclusionsUnder the conditions of this study, all systems caused apical debris extrusion. SAF instrumentation was associated with less debris extrusion compared with the use of hand and rotary files.

Salinia revisited: a crystalline nappe sequence lying above the Nacimiento fault and dispersed along the San Andreas fault system, central California

Salinia revisited: a crystalline nappe sequence lying above the Nacimiento fault and dispersed along the San Andreas fault system, central California

Self-Adjusting File Cleaning-Shaping-Irrigation System Optimizes the Filling of Oval-shaped Canals with Thermoplasticized Gutta-percha

IntroductionThis study aimed to compare the filling ability of carrier-based thermoplasticized gutta-percha in flat-oval canals prepared using either rotary ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland) or the Self-Adjusting File system (SAF) (ReDent-Nova, Ra'anana, Israel). MethodsThirteen pairs of mandibular incisors were selected from a random collection. The teeth in each pair had single root canals with a flat-oval cross-section and similar sizes and dimensions. Teeth from each pair were randomly assigned to 1 of 2 experimental groups. One group was instrumented using the ProTaper NiTi system, whereas the SAF system was used in the other. Root filling was performed with Thermafil obturators (Dentsply Tulsa Dental Products, Tulsa, OK), and teeth were sectioned at 6, 5, 4, and 3 mm from the apex; the cut surface was subjected to morphometric measurement to establish the percent gutta-percha–filled area (PGFA) for each section. The Wilcoxon matched-pairs signed rank test was used to assess the effect of the 2 preparation methods on the PGFA. ResultsThe median PGFA in the ProTaper group was 77.5%, whereas the median PGFA was 90.5% in the SAF group (P < .05). In the SAF-instrumented group, 17.8% of the specimens had a PGFA ≥95% compared with only 5.8% of the ProTaper-instrumented specimens (P < .05). ConclusionsInstrumentation of the flat-oval canals with the SAF system led to a significantly higher PGFA compared with ProTaper instrumentation with syringe and needle irrigation.

The non-covalent decoration of self-assembling protein fibers

The design of self-assembling fibers presents challenges in basic science, and has potential for developing materials for applications in areas such as tissue engineering. A contemporary issue in the field is the construction of multi-component, functionalized systems. Previously, we have developed peptide-based fibers, the SAF system, that comprises two complementary peptides, which affords considerable control over assembly and morphology. Here we present a straightforward route to functionalizing the SAFs with small molecules and, subsequently, other moieties. This is achieved via non-covalent recruitment of charged peptide tags, which offers advantages such as further control, reversibility, and future prospects for developing recombinant tags. We demonstrate the concept by appending fluorescent labels and biotin (and thence gold nanoparticles) to the peptides, and visualising the resulting decorated SAFs by light and electron microscopy. The peptide tags bind in the n m–μ m range, and show specificity compared with control peptides, and for the SAFs over similar α-helix-based peptide fibers.

Doolittle multivariate calibration algorithm and analysis of W, Mo, Ti–SAF system

Being an accurate and stable algorithm, Doolittle Decomposition Algorithm (DDA) was first introduced into the chemistry field. The basic principle of Doolittle Multivariate Calibration Algorithm (DMCA) was investigated, and the chromogenic system of W, Mo, Ti–SAF with overlapping absorption peaks was analyzed by DMCA. The computational relative standard deviation with DMCA is within ± 8.0% which was better than the result of K-Matrix (within ± 10.0%), the comparison indicated the superiority of Doolittle Decomposition Algorithm in the concentration analyzing. It was demonstrated that DDA can avoid matrix inverting, reduce the orders of matrixes and speed up the operation of matrixes. So it has bright prospects in chemometrics.