Search Results (15)

The aim of this study was to develop three-dimensional anatomical models of dogs with congenital extrahepatic portosystemic shunts (CEPSs) using 3D printing, as well as to detail their development process and compare the final models to volume rendering (VR) derived from computed tomography (CT) scans. CT scans in the Digital Imaging and Communications in Medicine (DICOM) format of two canine patients were used—one with splenocaval deviation and the other with right gastrocaval deviation. The images were segmented using 3DSlicer software, generating 3D files in Standard Tessellation Language (STL) format, which were then subjected to refinement and mesh adjustment using Blender software. The models were printed on a J750™ Digital Anatomy™ printer, followed by post-processing in a 2% sodium hydroxide solution for 72 h, with subsequent rinsing to remove support resin residues. The printed models showed colored anatomical structures, including the liver; spleen; kidneys; part of the arterial, venous, and portal circulations; and CEPSs. For comparison purposes, VR of the scans was recreated in the RadiAnt DICOM Viewer software. Despite some limitations of the segmentation software, the 3D-printed models effectively represented the anatomy of the patients and the CEPSs, demonstrating good equivalence to the VR. Full article

This paper examines the intellectual property (IP) challenges introduced by 3D printing, a transformative technology enabling widespread innovation, but also raising critical legal questions. It focuses on three main areas: (1) IP issues associated with 3D printing hardware, (2) copyright and licensing complexities related to downloadable 3D files, and (3) IP concerns for commercialized 3D printed items. Through a comprehensive review, the paper highlights how existing IP frameworks struggle to keep pace with the flexibility and accessibility inherent in 3D printing. Proposed solutions, such as blockchain for secure design tracking and enhanced digital rights management (DRM), point towards a more controlled future for digital design protection. Additionally, the study underscores the need for international cooperation to harmonize IP laws, facilitating more effective cross-border enforcement. This work aims to contribute to the ongoing dialogue on IP rights in 3D printing, proposing adaptive strategies to support legal clarity while fostering technological advancement. Full article

Although Three-dimensional (3D) printers have legitimate applications in various fields, they also present opportunities for misuse by criminals who can infringe upon intellectual property rights, manufacture counterfeit medical products, or create unregulated and untraceable firearms. The rise of affordable 3D printers for general consumers has exacerbated these concerns, making it increasingly vital for digital forensics investigators to identify and analyze vital artifacts associated with 3D printing. In our study, we focus on the identification and analysis of digital forensic artifacts related to 3D printing stored in both Linux and Windows operating systems. We create five distinct scenarios and gather data, including random-access memory (RAM), configuration data, generated files, residual data, and network data, to identify when 3D printing occurs on a device. Furthermore, we utilize the 3D printing slicing software Ultimaker Cura version 5.7 and RepetierHost version 2.3.2 to complete our experiments. Additionally, we anticipate that criminals commonly engage in anti-forensics and recover valuable evidence after uninstalling the software and deleting all other evidence. Our analysis reveals that each data type we collect provides vital evidence relating to 3D printing forensics. Full article

With the continuous advancement of information technology, a growing number of works, including articles, paintings, and music, are being digitized. Digital content can be swiftly shared and disseminated via the Internet. However, it is also vulnerable to malicious plagiarism, which can seriously infringe upon the rights of creators and dampen their enthusiasm. To protect creators’ rights and interests, a sophisticated method is necessary to authenticate digital intellectual property rights. Traditional authentication methods rely on centralized, trustworthy organizations that are susceptible to single points of failure. Additionally, these methods are prone to network attacks that can lead to data loss, tampering, or leakage. Moreover, the circulation of copyright information often lacks transparency and traceability in traditional systems, which leads to information asymmetry and prevents creators from controlling the use and protection of their personal information during the authentication process. Blockchain technology, with its decentralized, tamper-proof, and traceable attributes, addresses these issues perfectly. In blockchain technology, each node is a peer, ensuring the symmetry of information. However, the transparent feature of blockchains can lead to the leakage of user privacy data. Therefore, this study designs and implements an Ethereum blockchain-based intellectual property authentication scheme with privacy protection. Firstly, we propose a method that combines elliptic curve cryptography (ECC) encryption with digital signatures to achieve selective encryption of user personal information. Subsequently, an authentication algorithm based on Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (zk-SNARK) is adopted to complete the authentication of intellectual property ownership while encrypting personal privacy data. Finally, we adopt the InterPlanetary File System (IPFS) to store large files, solving the problem of blockchain storage space limitations. Full article

Background: Digital technology has been introduced in prosthodontics, and it has been widely used in denture duplication instead of a conventional denture duplication technique. However, research comparing different denture duplication techniques and how they affect the fitting accuracy of the denture base is scarce. Objectives: The aim was to assess the impact of duplication techniques on the accuracy of the fitting surface of computer-aided design and manufacturing (CAD-CAM) milled, 3D-printed, and injection-molded complete denture bases (CDBs). Methodology: This study involved fabricating a mandibular complete denture base with three marked dimples as reference marks (A, B, and C at the incisive papilla, right molar, and left molar areas) using a conventional compression molded technique. This denture was then scanned to generate a standard tessellation language (STL) file; after that, it was duplicated using three different techniques (milling, 3D printing, and injection molding) and five denture base resin materials—two milled CAD-CAM materials (AvaDent and IvoBase), two 3D-printed materials (NextDent and HARZ Labs), and one injection-molded material (iFlextm). Based on the denture base type, the study divided them into five groups (each with n = 10). An evaluation of duplication accuracy was conducted on the fitting surface of each complete denture base (CDB) using two assessment methods. The first method was a two-dimensional evaluation, which entailed linear measurements of the distances (A–B, A–C, and B–C) between reference points on both the scanned reference mandibular denture and the duplicated dentures. Additionally, a three-dimensional superimposition technique was employed, involving the overlay of the STL files of the dentures onto the reference denture’s STL file. The collected data underwent statistical analysis using a one-way analysis of variance and Tukey’s pairwise post hoc tests. Results: Both evaluation techniques showed significant differences in fitting surface accuracy between the tested CDBs (p ˂ 0.001), as indicated by one-way ANOVA. In addition, the milled CDBs (AvaDent and IvoBase) had significantly higher fitting surface accuracy than the other groups (p ˂ 0.001) and were followed by 3D-printed CDBs (NextDent and HARZ Labs), while the injection-molded (iFlextm) CDBs had the lowest accuracy (p ˂ 0.001). Conclusions: The duplication technique of complete dentures using a CAD-CAM milling system produced superior fitting surface accuracy compared to the 3D-printing and injection-molded techniques. Full article

Purpose: To report the rate of ocular torsion in children with horizontal strabismus or orthophoria. Methods: A retrospective study design was used. Nineteen children were included in the study, including seven girls, aged 4–16 years. All patients were examined for strabismus and 12 were scheduled for surgical intervention. All participants had digital fundus photos (DRSplus, Padova, Italy) of both eyes at presentation, and 5 of 12 also had fundus photos following the strabismus operation. Patient files were reviewed for age, demographic data, type of strabismus, clinical symptoms and signs, orthoptic exams, subjective and objective reports of torsion, inferior oblique overaction, and V pattern. Fundus photos were analyzed for torsion by ImageJ software [ImageJ 1.54f, National Institute of Health, USA]. The disc-foveal angle was calculated for ocular torsion. Disc-foveal angle was defined as the angle formed between a line passing through the center of the optic disc to the fovea and another horizontal line passing through the center of the optic disc, using fundus photographs. Results: Of the 19 children, 18 had horizontal strabismus: 9 with exotropia and 9 with esotropia. One child was orthophoric with torsional strabismus. Inferior oblique overaction was detected in all but 3 children, while V pattern was documented in 10. Visual acuity was reduced (under 6/12) in four eyes of four children. None were symptomatic for ocular torsion. Although extorsion was documented clinically in 3 of 19 children, it was measurable on fundus photos in all patients before surgery with a mean of 8.7 ± 8.5 degrees and 8.5 ± 9.7 degrees in the right and left eyes, respectively. The mean extorsion in both eyes was 19.7 ± 10.1 degrees and improved to a mean of 15.3 ± 7.9 degrees in the children who were operated on and had documented postoperative fundus photographs. Conclusions: Extorsion was detected on fundus photos at a significantly higher rate than in clinical examination. Notably, inferior oblique overaction was mainly associated with torsion. This study demonstrated that torsion is underdiagnosed in clinical examinations, as the children are often asymptomatic, but fundus photos which are easily obtained can improve its detection. Full article

With the advent of the digital age, traditional lifestyle activities, such as reading books, referencing recipes, and enjoying music, have progressively transitioned from offline to online. However, numerous issues plague the conventional approach to digital copyright protection. This is especially true in the realm of recipe protection, where the rights and interests of original creators are inadequately safeguarded due to the widespread dissemination of a large number of recipes on the Internet. This primarily stems from the high costs of gathering evidence, incomplete coverage of evidence collection, and the inability to identify and halt infringement activities in a timely manner during the process of traditional digital copyright protection. Therefore, this study designs and implements a blockchain-based digital recipe copyright protection scheme to address the issues of insufficient legal evidence and cumbersome processes in traditional digital copyright protection. First, we enhance standard short text similarity calculation method SimHash, boosting the accuracy of text similarity detection. We then utilize the decentralization, immutability, time-stamping, traceability, and smart contract features of blockchain technology for data privacy protection. We employ the Interplanetary File System (IPFS) to store raw data, thereby ensuring user privacy and security. Lastly, we improve the proxy voting node selection in the existing delegated proof of stake (DPOS) consensus mechanism. According thorough evaluation and empirical analysis, the scheme effectively improves the accuracy of text similarity detection. Simultaneously, the enhanced DPOS mechanism effectively rewards nodes with excellent performance and penalizes nodes exhibiting malicious behavior. In this study, we successfully designed and implemented an innovative digital recipe copyright protection scheme. This scheme effectively enhances the accuracy of text similarity detection; ensures the privacy and security of user data; and, through an enhanced DPOS mechanism, rewards well-performing nodes while penalizing those exhibiting malicious behavior. Full article

This study aimed to investigate the accuracy of gingival thickness measurement by two methods of clinical evaluation and intraoral ultrasonography. The gingival thickness was measured in the midbuccal area of the right maxillary lateral incisor and first molar teeth in 30 individuals. For clinical measurement, a #15 K-file with rubber stops was vertically inserted 2 mm apical to the gingival margin and the length of the file in the tissue was measured using a digital caliper. Ultrasonographic measurement was performed using an intraoral probe on the gingival surface in the midbuccal area, at the entry point of the file. Statistical analysis was performed by paired t-test, correlation coefficient, and receiver operating characteristic (ROC) curve (α = 0.05). In the anterior region, the mean gingival thicknesses using ultrasonography (1.517 ± 0.293 mm) and clinical evaluation (1.610 ± 0.272 mm) were not significantly different (p = 0.434). In the posterior region, the mean gingival thicknesses were significantly different between ultrasonography (1.372 ± 0.442 mm) and clinical evaluation (1.626 ± 0.310 mm) (p = 0.006). The area under ROC curve values for ultrasonographic measurements in the anterior and posterior regions were 0.681 and 0.597, respectively. The use of ultrasonography with an intraoral probe has acceptable accuracy for the determination of gingival thickness, especially for the anterior regions. Full article

Objectives: Few studies have evaluated the marginal fit of computer-aided design—computer-aided manufacturing (CAD-CAM) monolithic zirconia crowns fabricated through completely digital workflow; however, the internal fit of these restorations is not well known. The purpose of this in vitro study was to evaluate the marginal and internal fit of monolithic zirconia crowns fabricated by using digital workflow, including intraoral scanner (IOS) scans, and compare the results to those of a semi-digital workflow, which combined conventional impressions, poured casts, and extraoral scanner (EOS) scanning. Materials and methods: A typodont right mandibular first molar was prepared for a complete-coverage ceramic crown and scanned using an IOS. The conventional impressions of the preparation were also made, and stone casts were poured and scanned by using an EOS. Virtual models were generated for both workflows, and identical virtual anatomic contour crowns were designed using CAD software. Monolithic zirconia crowns were fabricated for both IOS (ZI; n = 10) and EOS (ZE; n = 10) groups. The silicon replica technique was used to evaluate the marginal and internal fit of the crowns. Measurements were made at 13 points on buccolingual and mesiodistal cross-sections per specimen with a ×6.5 to ×50 zoom stereo microscope. The results from both groups were statistically compared using the Independent Samples t-tests and the Mann–Whitney U test (α = 0.05). Results: Mean gap values at all measurement locations for ZE were significantly higher than those for ZI (p ≤ 0.002). Overall mean values ranged between 29 and 43 µm (median: 28–42 µm) for ZI and 42 and 75 µm (median: 43–77 µm) for ZE. Conclusion: Completely digital workflow through intraoral scans provided significantly better marginal and internal fit for CAD-CAM monolithic zirconia crowns compared with the semi-digital workflow, where stone casts obtained from conventional impressions were scanned with an EOS. Yet, both workflows provided an acceptable marginal and internal fit for CAD-CAM monolithic zirconia molar crowns (<120 µm). Clinical Relevance: Completely digital workflow using IOS scans may be advantageous for the fabrication of CAD-CAM monolithic zirconia crowns as favorable results can be obtained with less material waste and potentially shortened overall treatment time as the impression files can be transferred to the production facility electronically. The results need to be corroborated with clinical studies. Full article

The relevance of this study stems from the fact that the development of a market for financial instruments can significantly expand lending opportunities for small- and medium-sized businesses. While research on the impact of tokenization on financial markets is extensive, literature provides virtually no description of mathematical models that can be used in the design and development of information systems issuing tokenized financial instruments. Thus, the study aims to develop mathematical models representing the transformation of the over-the-counter (OTC) securities market induced by the tokenization of underlying assets. The development of crowdlending platforms is gradually transforming the financial market landscape. The key change trends consist in transactional fragmentation both on the demand and supply sides. This paper proposes a mathematical model of internal transformation occurring in the OTC financial market, which describes the process of managing rights to underlying assets during their issuance and circulation. The model is built by analogy with the Harrison–Ruzzo–Ullman (HRU) model, applying the same principles to the relations of economic agents in exercising access rights to underlying assets as those that regulate access rights to files. The research novelty of the presented model consists in the formalization of financial market transformation occurring in the context of asset tokenization, which significantly expands the mathematical apparatus of digital financial transactions. This paper also proposes a mathematical model of competitive tokenization-induced transformation occurring in the OTC financial market, which describes transaction costs associated with attracting investment in the OTC financial market and the market for tokenized assets. In addition, the barriers of the OTC financial market and the stock market are described indicating the supply and demand trends in the context of transformation occurring in the OTC financial market under the influence of underlying asset tokenization. The novelty of this model lies in the mathematical formalization of the investment attraction process in the market for tokenized assets. The theoretical value of the developed models consists in the confirmation of significantly expanded supply capabilities of tokenized assets on the graph showing the dependence of asset returns on invested capital. Full article

We report on the exemplified realization of a digital to physical process chain for a patient individualized osteosynthesis plate for the tarsal bone area. Anonymized patient-specific data of the right feet were captured by computer tomography, which were then digitally processed to generate a surface file format (standard tessellation language, STL) ready for additive manufacturing. Physical realization by selective laser melting in titanium using optimized parameter settings and post-processing by stress relief annealing results in a customized osteosynthesis plate with superior properties fulfilling medical demands. High fitting accuracy was demonstrated by applying the osteosynthesis plate to an equally good 3D printed bone model, which likewise was generated using the patient-specific computer tomography (CT) data employing selective laser sintering and polyamid 12. Proper fixation has been achieved without any further manipulation of the plate using standard screws, proving that based on CT data, individualized implants well adapted to the anatomical conditions can be accomplished without the need for additional steps, such as bending, cutting and shape trimming of precast bone plates during the surgical intervention. Beyond parameter optimization for selective laser melting, this exemplified digital to physical process chain highlights the potential of additive manufacturing for individualized osteosynthesis. Full article

(1) Background: Occlusal vertical dimension (OVD) in the optimal maxillo–mandibular relationship is an important parameter to establish when complex dental rehabilitation has to be done. The optimal method to measure OVD is still a challenge in everyday practice. The aim of the present study was to test the reliability of the correlation between OVD and some anthropometric and cephalometric methods described in the literature. The validity of OVD registration using a facial scanner was also assessed. (2) Materials and Methods: 150 dentate participants, aged 20–25 years, were randomly selected using sealed envelopes. Anthropometric measurements between specific standard points were performed: Subnasion–Prementon (Sn–PM) and Subnasion–Gnation (Sn–Gn) in maximum intercuspation and in the rest mandibular position, right and left pupil to the corresponding chelion. The cephalometric measurements registered were the lower facial angle and the angle between mandibular and Frankfurt planes. The distance Sn–Gn in maximum intercuspation was compared to all other parameters. Facial scanning, with a mobile phone and installed dedicated application, was performed on ten subjects, randomly selected using the same method among the participants, and the obtained 3D files were analyzed. The digital measurements were compared, for validity, to the clinical measurements. Pearson’s correlation coefficient was used, for comparing clinical Sn–Gn in maximum intercuspation position to the other parameters. (3) Results: A strong agreement between all measured anthropometric parameters of the facial scan and clinical contact measurement method was registered. None of the measured parameters could predict the exact OVD. (4) Conclusions: In the limits of our study, the facial scanning could be used for predictable registration of OVD and the stored digital information could be preserved through life and use for oral rehabilitation. However, if OVD needs to be determined, several measurement methods, including cephalometric measurements, need to be used simultaneously to reach a final decision. Full article

The copyright of data is a key point that needs to be solved in spatial data infrastructure for data sharing. In this paper, we propose a decentralized digital rights management model of spatial data, which can provide a novel way of solving the existing copyright management problem or other problems in spatial data infrastructure for data sharing. An Ethereum smart contract is used in this model to realize spatial data digital rights management function. The InterPlanetary File System is utilized as external data storage for storing spatial data in the decentralized file system to avoid data destruction that is caused by a single point of failure. There is no central server in the model architecture, which has a completely decentralized nature and it makes spatial data rights management not dependent on third-party trust institutions. We designed three spatial data copyright management algorithms, developed a prototype system to implement and test the model, used the smart contract security verification tool to check code vulnerabilities, and, finally, discussed the usability, scalability, efficiency, performance, and security of the proposed model. The result indicates that the proposed model not only has diversified functions of copyright management compared with previous studies on the blockchain-based digital rights management, but it can also solve the existing problems in traditional spatial data infrastructure for data sharing due to its characteristics of complete decentralization, mass orientation, immediacy, and high security. Full article

The access economy business model has been applied to a wide range of digital goods and services such as software, movies, music, and books. The digital platforms that manage transactions between buyers and sellers enable product rights owners to define product usage rights with a great deal of precision. In this paper, music product usage rights for digital consumption and platform attributes of music streaming systems are discussed and a model for digital music streaming system adoption and digital piracy is presented. The results of a quasi-experiment suggest that the perceived freedom to tryout, modify, and share digital music products contribute to both perceived usefulness and perceived enjoyment of a product format and the music streaming system. In turn, perceived usefulness and perceived enjoyment lead to the intention to adopt a music streaming system. The perceived usefulness of a music streaming system is associated with a reduction of pirating intention. Full article

River basin delineation can be inappropriate to determine surface water availability in a country, even if it is established by its water authority. This is because the effect of agricultural and urban infrastructure in runoff direction is ignored, and the anthropogenic changes in hydrography and topography features distort the runoff. This situation is really important because water rights are granted based on volumes that are not physically accessible. The existence of this problem is demonstrated through a case of study: the Culiacan River Basin in Mexico. To overcome such a situation, this study poses criteria to revise official river basin configurations and to delineate new river basins based on digital elevation models, vector files of agricultural infrastructure, and extensive field verification. Significant differences were noticed in surface water availability calculated under distinct river basin delineations. Full article