The primary goals of this study were to identify the influence of temperature and drying time on pretreated cassava flour, as well as the optimal settings for the factors and to analyze the microstructure of cassava flour. The experiment was designed using the response surface methodology with central composite design and the superimposition approach in order to assess the effect of drying temperature (45.85-74.14 °C) and drying time (3.96-11.03 h) and the optimal drying conditions of the cassava flour investigated. Soaking and blanching were applied as pretreatments to freshly sliced cassava tubers. The value moisture content of cassava flour was between 6.22% and 11.07%, whereas the observed whiteness index in cassava flour ranged from 72.62 to 92.67 in all pretreated cassava flour samples. Through analysis of variance, each drying factor, their interaction, and all squared terms had a substantial impact on moisture content and whiteness index. The optimized values for drying temperature and drying time for each pretreated cassava flour were 70 °C and 10 h, respectively. The microstructure showed a non-gelatinized, relatively homogeneous in size and shape sample with pretreatment soaked in distilled water at room temperature. These study results are relevant to the development of more sustainable cassava flour production.

• Klíčová slova
• blanching, cassava flour, central composite design, soaking, superimposition,
• Publikační typ
• časopisecké články MeSH

In this study, we optimized a method for the determination of free amino acids in Nicotiana tabacum leaves. Capillary electrophoresis with contactless conductivity detector was used for the separation of 20 proteinogenic amino acids in acidic background electrolyte. Subsequently, the conditions of extraction with HCl were optimized for the highest extraction yield of the amino acids because sample treatment of plant materials brings some specific challenges. Central composite face-centered design with fractional factorial design was used in order to evaluate the significance of selected factors (HCl volume, HCl concentration, sonication, shaking) on the extraction process. In addition, the composite design helped us to find the optimal values for each factor using the response surface method. The limits of detection and limits of quantification for the 20 proteinogenic amino acids were found to be in the order of 10-5 and 10-4 mol l-1, respectively. Addition of acetonitrile to the sample was tested as a method commonly used to decrease limits of detection. Ambiguous results of this experiment pointed out some features of plant extract samples, which often required specific approaches. Suitability of the method for metabolomic studies was tested by analysis of a real sample, in which all amino acids, except for L-methionine and L-cysteine, were successfully detected. The optimized extraction process together with the capillary electrophoresis method can be used for the determination of proteinogenic amino acids in plant materials. The resulting inexpensive, simple, and robust method is well suited for various metabolomic studies in plants. As such, the method represents a valuable tool for research and practical application in the fields of biology, biochemistry, and agriculture.

• Klíčová slova
• Amino acids, Capillary electrophoresis, Central composite design, Factorial design, Response surface method, Tobacco,
• MeSH
• aminokyseliny izolace a purifikace   MeSH
• elektroforéza kapilární metody   MeSH
• listy rostlin chemie   MeSH
• tabák chemie   MeSH
• teoretické modely MeSH
• Publikační typ
• časopisecké články MeSH
• validační studie MeSH
• Názvy látek
• aminokyseliny MeSH

Three types of chiral stationary phase were used to achieve chromatographic resolution of enantiomers of rac-11-dihydrooracin (DHO), the principal metabolite of a potential cytostatic drug oracin. Chiralcel OD-R as a chiral stationary phase with mobile phase comprising acetonitrile (modifier) and sodium perchlorate (buffering component) proved to be the most suitable system. Chemometric optimisation based on the Box-Wilson central composite design was employed to find the optimum resolution. The optimum factor space was defined by three parameters: temperature, modifier concentration and buffer concentration. Newly designed chromatographic response functions based on a combination of resolution R(S) and retention time of the last component eluted t(RL) were employed to evaluate the resolution with regard to quality and quantity. Optimum values predicted from those models of response surfaces were in excellent agreement with the experimental results. The chromatographic resolution of DHO enantiomers is suitable for xenobiochemical studies on stereoselectivity and stereospecificity of biotransformation enzymes.

• MeSH
• ethanolaminy analýza   chemie   izolace a purifikace   metabolismus   MeSH
• isochinoliny analýza   chemie   izolace a purifikace   metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• reprodukovatelnost výsledků MeSH
• řízení kvality MeSH
• roztoky chemie   MeSH
• senzitivita a specificita MeSH
• stereoizomerie MeSH
• techniky kombinatorické chemie metody   MeSH
• teplota MeSH
• vysokoúčinná kapalinová chromatografie přístrojové vybavení   metody   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• validační studie MeSH
• Názvy látek
• ethanolaminy MeSH
• isochinoliny MeSH
• oracine MeSH Prohlížeč
• roztoky MeSH

BACKGROUND: The present study focused on the production of L-asparaginase using Solid State Fermentation (SSF) by Myroides gitamensis. METHODS: Initially, five significant parameters (Carbon source; Nitrogen source, temperature, pH and incubation period) were identified that affect the production process of L-asparaginase using Classical One Factor at a Time (OFAT) optimization. An optimized L-asparaginase specific activity obtained by OFAT was recorded as 85.7 IU. Central Composite Design (CCD) was also employed successively to optimize the multiple parameters at a time and their results were compared. RESULTS: Maximum L-asparaginase enzyme specific activity obtained by CCD method was 295.6 IU under the hold values of carbon source (wheat bran) 12 g/L, nitrogen source (yeast extract) 7 g/L, temperature 37°C, pH=7.5 and incubation period 47 hr. Upon validation, the obtained results proved that there was a good relation existing between the experimental and the predicted model (p<0.05). L-asparaginase activity was enhanced in statistical method up to 3.4 folds compared to that of classical method. CONCLUSION: Utilization of wheat bran as a low cost carbon source in SSF for the production of L-asparaginase enzyme makes the process economical and in turn reduces the environmental pollution by biotransformation to commercially useful bio product.

• Klíčová slova
• Biotransformation, Bran, Environmental pollution, Fermentation, L-asparaginase, Myroides gitamensis, Wheat,
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: Restorative treatment of anterior teeth is often required as the final step of orthodontic therapy to optimize the esthetics and function. This case report presents a direct minimally invasive approach for post-orthodontic recontouring of anterior teeth using the composite injection technique with a digital workflow. CLINICAL CONSIDERATIONS: The extraction of central incisors with short roots was indicated to resolve maxillary anterior crowding. The gained space was closed with lateral incisors, and it was necessary to recontour them and canines to resemble central and lateral incisors, respectively. The restorations were digitally designed, and a transparent silicone index was fabricated from a 3D-printed cast of the digital wax-up. After lateral incisors and canines were bonded with a universal adhesive in the etch-and-rinse mode, a highly filled injectable composite resin was applied into the index. The restorative treatment was preceded by gingivectomy using an Er:YAG laser and home bleaching. CONCLUSIONS: In cases where more complex recontouring of anterior teeth is necessary, the composite injection technique could be a suitable alternative to indirect restorations, because it is straightforward, cost-effective, and does not require any preparation. The digital workflow simplified and expedited the treatment while contributing to its precision. CLINICAL SIGNIFICANCE: Post-orthodontic recontouring using direct composite restorations is well accepted by patients due to low cost and non-invasiveness. However, in complicated cases, the free-hand technique is time-consuming and technique-sensitive. The presented composite injection technique with a digital workflow significantly simplifies and expedites the composite placement while predictably enhancing the treatment outcome.

• Klíčová slova
• CAD/CAM, bleaching, digital dentistry, operative dentistry, periodontics/orthodontics,
• MeSH
• estetika stomatologická MeSH
• lidé MeSH
• průběh práce * MeSH
• řezáky MeSH
• složené pryskyřice MeSH
• trvalá zubní náhrada * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• složené pryskyřice MeSH

In this article, optimization of BGE for simultaneous separation of inorganic ions, organic acids, and glutathione using dual C4 D-LIF detection in capillary electrophoresis is presented. The optimized BGE consisted of 30 mM 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid, 15 mM 2-amino-2-hydroxymethyl-propane-1,3-diol, and 2 mM 18-crown-6 at pH 7.2 and allowed simultaneous separation of ten inorganic anions and cations, three organic acids and glutathione in 20 min. The samples were injected hydrodynamically from both capillary ends using the double-opposite end injection principle. Sensitive detection of anions, cations, and organic acids with micromolar LODs using C4 D and simultaneously glutathione with nanomolar LODs using LIF was achieved in a single run. The developed BGE may be useful in analyses of biological samples containing analytes with differing concentrations of several orders of magnitude that is not possible with single detection mode.

• Klíčová slova
• Capillary electrophoresis, Contactless conductivity detection, Dual detection, Laser induced fluorescence detection, Saliva,
• MeSH
• dechové testy metody   MeSH
• design vybavení MeSH
• elektrická vodivost MeSH
• elektroforéza kapilární metody   MeSH
• fluorescenční spektrometrie metody   MeSH
• glutathion analýza   izolace a purifikace   MeSH
• ionty analýza   izolace a purifikace   MeSH
• kyseliny karboxylové analýza   izolace a purifikace   MeSH
• lidé MeSH
• limita detekce MeSH
• lineární modely MeSH
• reprodukovatelnost výsledků MeSH
• slzy chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glutathion MeSH
• ionty MeSH
• kyseliny karboxylové MeSH

OBJECTIVE: To evaluate the influence of different types of modifications with resin on fatigue resistance and failure behavior of CAD-CAM resin nano ceramic (RNC) restorations for maxillary first premolars. METHODS: Sixty standardized resin composite root dies received CAD-CAM RNC endocrowns (n=30) and crowns (n=30) (Lava Ultimate, 3M Espe). Restorations were divided into six groups: full anatomic endocrowns (group A) and crowns (group D), buccal resin veneered endocrowns (group B) and crowns (group E) and buccal resin veneered endocrowns (group C) and crowns (group F) with a central groove resin filling. A nano-hybrid resin composite was used to veneer the restorations (Filtek Supreme, 3M Espe). All specimens were first submitted to thermo-mechanical cyclic loading (1.7Hz, 49N, 600000 cycles, 1500 thermo-cycles) and then submitted to cyclic isometric stepwise loading (5Hz) until completion of 105000 cycles or failure after 5000 cycles at 200N, followed by 20000 cycles at 400N, 600N, 800N, 1000N and 1200N. In case of fracture, fragments were analyzed using SEM and modes of failure were determined. Results were statistically analyzed by Kaplan-Meier life survival analysis and log rank test (p=0.05). RESULTS: The differences in survival between groups were not statistically significant, except between groups D and F (p=0.039). Endocrowns fractured predominantly with a mesio-distal wedge-opening fracture (82%). Partial cusp fractures were observed above all in crowns (70%). Analysis of the fractured specimens revealed that the origin of the fracture was mainly at the occlusal contact points of the stepwise loading. SIGNIFICANCE: Veneering of CAD-CAM RNC restorations has no influence on their fatigue resistance except when monolithic crowns are modified on their occlusal central groove.

• Klíčová slova
• CAD/CAM, Endocrown, Endodontically treated teeth, Fatigue, Fractography, Lava Ultimate, Veenering,
• MeSH
• analýza zatížení zubů MeSH
• design s pomocí počítače * MeSH
• složené pryskyřice MeSH
• zubní korunky * MeSH
• zubní porcelán * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• složené pryskyřice MeSH
• zubní porcelán * MeSH

Nanosized drug crystals have been reported with enhanced apparent solubility, bioavailability, and therapeutic efficacy compared to microcrystal materials, which are not suitable for parenteral administration. However, nanocrystal design and development by bottom-up approaches are challenging, especially considering the non-standardized process parameters in the injection step. This work aims to present a systematic step-by-step approach through Quality-by-Design (QbD) and Design of Experiments (DoE) for synthesizing drug nanocrystals by a semi-automated nanoprecipitation method. Curcumin is used as a drug model due to its well-known poor water solubility (0.6 µg mL-1, 25 °C). Formal and informal risk assessment tools allow identifying the critical factors. A fractional factorial 24-1 screening design evaluates their impact on the average size and polydispersity of nanocrystals. The optimization of significant factors is done by a Central Composite Design. This response surface methodology supports the rational design of the nanocrystals, identifying and exploring the design space. The proposed joint approach leads to a reproducible, robust, and stable nanocrystalline preparation of 316 nm with a PdI of 0.217 in compliance with the quality profile. An orthogonal approach for particle size and polydispersity characterization allows discarding the formation of aggregates. Overall, the synergy between advanced data analysis and semi-automated standardized nanocrystallization of drugs is highlighted.

• Klíčová slova
• design space, nanocrystals, orthogonal characterization, response surface methodology, solvent–antisolvent precipitation,
• MeSH
• automatizace MeSH
• krystalizace MeSH
• kurkumin chemie   MeSH
• léčivé přípravky chemie   MeSH
• nanočástice * chemie   MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kurkumin MeSH
• léčivé přípravky MeSH

We have developed a new microextraction technique for equilibrium, non-exhaustive analyte preconcentration from aqueous solutions into organic solvents lighter than water. The key point of the method is application of specially designed and optimized bell-shaped extraction device, BSED. The technique has been tested and applied to the preconcentration of selected volatile and semi volatile compounds which were determined by gas chromatography/mass spectrometry in spiked water samples. The significant parameters of the extraction have been found using chemometric procedures and these parameters were optimized using the central composite design (CCD) for two solvents. The analyte preconcentration factors were in a range from 8.3 to 161.8 (repeatability from 7 to 14%) for heptane, and 50.0-105.0 (repeatability from 0 to 5%) for tert-butyl acetate. The reproducibility of the technique was within 1-8%. The values of limits of detection and determination were 0.1-3.3 ng mL(-1) for heptane and 0.3-10.7 ng mL(-1) for tert-butyl acetate. The new microextraction technique has been found to be a cheap, simple and flexible alternative to the common procedures, such as SPME or LLME. This BSED-LLME technique can also be combined with other separation methods, e.g., HPLC or CE.

• MeSH
• chemické látky znečišťující vodu analýza   izolace a purifikace   MeSH
• design vybavení MeSH
• mikroextrakce kapalné fáze přístrojové vybavení   metody   MeSH
• minerální vody analýza   MeSH
• pitná voda analýza   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• reprodukovatelnost výsledků MeSH
• voda analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• minerální vody MeSH
• pitná voda MeSH
• voda MeSH

This paper introduces a complex novel concept and methodology for the creation of personalized biomedical appliances 3D-printed from certified biocompatible photopolymer resin Dental LT Clear (V2). The explained workflow includes intraoral and CT scanning, patient virtualization, digital appliance design, additive manufacturing, and clinical application with evaluation of the appliance intended for patients with cranio-facial syndromes. The presented concept defines virtual 3D fusion of intraoral optical scan and segmented CT as sufficient and accurate data defining the 3D surface of the face, intraoral and airway morphology necessary for the 3D design of complex personalized intraoral and extraoral parts of the orthopedic appliance. A central aspect of the concept is a feasible utilization of composite resin for biomedical prototyping of the sequence of marginally different appliances necessary to keep the pace with the patient rapid growth. Affordability, noninvasiveness, and practicality of the appliance update process shall be highlighted. The methodology is demonstrated on a particular case of two-year-old infant with Pierre Robin sequence. Materialization by additive manufacturing of this photopolymer provides a highly durable and resistant-to-fracture two-part appliance similar to a Tübingen palatal plate, for example. The paper concludes with the viability of the described method and material upon interdisciplinary clinical evaluation of experts from departments of orthodontics and cleft anomalies, pediatric pneumology and phthisiology, and pediatric otorhinolaryngology.

• Klíčová slova
• 3D printed orthopedic appliance, CT, Infants, Tübingen palatal plate, airway obstruction, biocompatible photopolymer resin, craniofacial anomalies, micrognathia, orthodontics,
• Publikační typ
• časopisecké články MeSH