An approach to computer-aided design: a tool for mathematical modelling in biology and ecology.
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Animals↗
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Computer-aided gene design.
A computer program, which runs on MS-DOS personal computers, is described that assists in the design of synthetic genes coding for proteins. The goal of the program is the design of a gene which (i) contains as many unique restriction sites as possible and (ii) uses a specific codon usage. The gene designed according to the criteria above is (i) suitable for 'modular mutagenesis' experiments and (ii) optimized for expression. The program 'reverse-translates' protein sequences into degenerated DNA sequences, generates a map of potential restriction sites and locates sequence positions where unique restriction sites can be accommodated. The nucleic acid sequence is then 'refined' according to a specific codon usage to remove any degeneration. Unique restriction sites, if potentially present, can be 'forced' into the degenerated nucleic acid sequence by using 'priority codes' assigned to different restriction sequences.
Amino Acid Sequence↗
Computer analysis of interacting dopaminergic and cholinergic control mechanisms in the extrapyramidal system.
The experimental results of many authors suggest that the output activity of the extrapyramidal motor control system depends on a balance between the levels present of the chemical transmitters dopamine and acetylcholine. In this paper it is proposed that these results are best explained by two feedback regulatory systems interconnected with positive interaction--in the sense of the relative gain array (Bristol, 1966). Using the computer-aided design procedure CAIAD, a simple two-input two-output model is simulated so as to give responses similar to those observed when dopaminergic or cholinergic drugs are applied. The effect of reducing the gain in one control loop corresponds to the effect of lesioning part of the extrapyramidal system in the brain. In addition, the effect of an anti-schizophrenic drug such as haloperidol is interpreted as a disturbance input on one of the interacting paths.
Acetylcholine↗
Application of Three-Dimensionally Printed Surgical Guides in Precise Sacral Tumor Excision and Defect Reconstruction.
OBJECTIVE: Precise resection of sacral tumors remains technically demanding due to their deep anatomical location and close proximity to critical neurovascular structures. Conventional freehand techniques often result in suboptimal resection margins, excessive blood loss, and compromised lumbopelvic stability. This study evaluated whether patient-specific three-dimensional (3D)-printed guiding templates improve surgical accuracy and perioperative outcomes in sacral tumor resection and reconstruction. METHODS: Nineteen patients undergoing en bloc sacral tumor resection (S1-S3 involvement) with spinopelvic reconstruction (2006-2020) were retrospectively analyzed. Patients were divided into a 3D-printing group (n = 10) and a conventional freehand group (n = 9). In the 3D-printing group, computer-aided design and 3D-printed templates were used for osteotomy, screw placement, and defect reconstruction. Perioperative metrics, surgical accuracy, and complications were compared between groups using Welch's t-test and the Hodges-Lehmann method; oncologic events during follow-up were recorded descriptively. RESULTS: The 3D-printing group demonstrated significantly shorter operative time (456.5 ± 62.36 vs. 574.44 ± 114.58 min, p = 0.012), reduced blood loss (4081.40 ± 838.99 vs. 5090.0 ± 1059.67 mL, p = 0.034), and fewer fluoroscopic exposures (4.2 ± 0.79 vs. 10.0 ± 1.58, p < 0.001) compared with the conventional group. Osteotomy accuracy was also superior in the 3D-printing group, with significantly lower angular deviation (3.33° ± 0.45° vs. 6.79° ± 2.16°, p = 0.0012). Postoperative complication rates were comparable (30% vs. 44.4%, p = 0.649), but hospital stay was significantly shorter in the 3D-printing group (10.7 ± 2.71 vs. 18.11 ± 4.01 days, p < 0.001). CONCLUSION: Patient-specific 3D-printed guiding templates enhance precision in sacral tumor excision and reconstruction, improving surgical efficiency and perioperative safety. This computer-assisted, template-guided approach represents a valuable advancement for complex sacral oncologic surgery.
Humans↗
A systematic approach to thermal conductivity detector design I. Use of computer-aided data acquisition for the evaluation of cell contributions to peak shape.
The design of thermal conductivity detectors for open tubular gas chromatography was systematically investigated with the aid of modern digital data acquisition techniques. Two important factors in such a design are sensitivity and peak broadening. The latter factor was the principle thrust of this work and contributions to peak shape from both cell design and volume were analyzed by the method of statistical moments. Peak variance (the mean square displacement along the x-axis of a chromatographic peak) was shown to correlate directly with cell volume in cells of the same design but both variance and asymmetry were found to be design dependent.
Chromatography, Gas↗
Chairside computer-generated ceramic restorations: the Cerec third generation improvements.
Cerec chairside computer-generated ceramic restorations have well passed a five-year clinical observation period with convincing clinical success. The new system COS 2.1 allows an essentially automatic design of inlays, the construction of 3/4 and 4/5 cusp protection onlays, and individually-shaped aesthetic laminate veneers. The new E-drive grinding increases the machining capacity by factor 3 to 4, reduces edge roughness by 50%, and doubles machining precision. Cementation gap width at the cervical margin is 37-48 microns in normal-depth preparations and 54-76 microns in deep cavities. It is the purpose of this article to review the third generation improvements of this method.
Adult↗
Virtual surgical planning-assisted versus free-hand head and neck reconstruction: Systematic review, meta-analysis, and a novel classification.
Virtual surgical planning (VSP)-assisted reconstruction is increasingly used as an alternative to conventional free-hand (FH) techniques in mandibular and maxillary free-flap reconstruction. This systematic review and meta-analysis compared clinical outcomes and proposed a Reconstruction Complexity-Completeness classification. PubMed/MEDLINE, Scopus, Web of Science, Google Scholar, and reference lists were searched from inception to 20 June 2026. Comparative studies were eligible. Risk of bias was assessed using RoB 2 or the Newcastle-Ottawa Scale. Random-effects meta-analyses used restricted maximum likelihood estimation and Hartung-Knapp adjustment. Forty-two studies included 2763 patients (1204 VSP; 1559 FH). VSP significantly reduced operative time (33 studies; MD -64.75 min, 95% CI -83.51 to -46.00), ischemia time (15 studies; MD -37.40 min, 95% CI -48.97 to -25.82), and hospital stay (16 studies; MD -1.75 days, 95% CI -3.43 to -0.08). VSP was associated with significantly lower odds of bony non-union (OR 0.31, 95% CI 0.16-0.59) and malocclusion (OR 0.14, 95% CI 0.03-0.64), whereas flap loss, surgical site infection, and plate exposure did not differ significantly. VSP-assisted reconstruction was associated with improved operative efficiency, shorter hospitalization, and lower odds of bony non-union and malocclusion, while no statistically significant differences were detected in flap loss, surgical site infection, or plate exposure. The proposed classification may support complexity-adjusted reporting and comparison.
Humans↗
Clinical performance of two lithium disilicate CAD/CAM materials in posterior Class II inlay restorations: A 48-month randomised split-mouth clinical trial.
OBJECTIVES: To compare the clinical performance of Amber Mill (AM) and IPS e.max CAD (EM) lithium disilicate computer-aided design/computer-aided manufacturing (CAD/CAM) materials in posterior Class II inlay restorations and characterise their baseline properties. METHODS: Thirty-four adults received paired AM and EM posterior Class II inlays (68 restorations) in a triple-blind randomised split-mouth trial followed for 48 months. Restorations were evaluated at baseline and annually using revised World Dental Federation (FDI) criteria, with fracture and retention as the primary endpoint. Baseline characterisation included flexural strength, shear bond strength, translucency parameter, and scanning electron microscopy. McNemar, Wilcoxon signed-rank, Friedman, one-way analysis of variance, Tukey post hoc, and inter-rater agreement analyses were used. RESULTS: At 48 months, 18 paired participants were available for primary analysis. Failures occurred in 2 of 18 AM restorations and in 3 of 18 EM restorations, corresponding to success rates of 88.9% and 83.3%, respectively, with no significant between-material difference (McNemar p = 1.000). No catastrophic bulk ceramic fracture was observed. Secondary FDI scores remained mostly within the clinically acceptable range; marginal staining deteriorated over time in both groups (p < .001) without significant between-material differences. Baseline material testing showed significant material- and translucency-dependent differences in flexural strength, shear bond strength, and translucency. CONCLUSIONS: Within the limitations of the 48-month follow-up and the tested Class II inlay indication, AM showed clinical performance comparable to EM. Observed clinical complications were related to retention or marginal/interface behaviour. CLINICAL SIGNIFICANCE: For posterior Class II lithium disilicate CAD/CAM inlays, medium-term complications were mainly retention/interface-related, suggesting adhesive-interface durability may be as important as baseline ceramic strength.
Humans↗
Selective Macrocyclic WEE1 Kinase Inhibitors with Strong Efficacy against Patient-Derived Colorectal Cancer Organoids.
Macrocyclization can enhance the selectivity of acyclic compounds toward structurally similar biological targets such as kinases. WEE1 regulates cellular homeostasis and is a promising target in oncology. The clinical candidate AZD1775 (1) failed to progress past Phase II trials because of patient tolerability issues, likely due to off-target inhibition of polo-like kinase 1 (PLK1). Herein, a computer-aided drug design approach was conducted to develop a macrocycle based on the 1-WEE1 X-ray cocrystal structure. Significantly enhanced WEE1 inhibitory selectivity over PLK1 was determined for leading macrocycle 2, which also demonstrated broader kinome-wide selectivity. Patient-derived organoids from colorectal cancer (CRC) peritoneal and liver metastases, treated with 2, demonstrated comparably strong or enhanced anticancer efficacy compared to that of 1. Against patient-matched normal colon vs primary CRC organoids, 2 potently and selectively treated CRC, as well as enhanced DNA damage compared to 1. Finally, the X-ray cocrystal structure of 2 bound to WEE1 validated its computationally predicted bioactive binding mode.
Humans↗
HIF1A+CSF3R+ neutrophils-dominated hypoxic niche induced metabolic reprogramming for neoadjuvant therapy resistance in NSCLC.
BACKGROUND: Non-small cell lung cancer (NSCLC) is one of the frequently occurring cancers characterized by molecular heterogeneity and multiple immune cell infiltration patterns, which are associated with treatment sensitivity and resistance. However, the specific microenvironmental cells and their mechanisms that lead to treatment resistance in patients need to be explored in greater depth. METHODS: On the basis of patients receiving neoadjuvant therapy in our center, a multicenter, multicohort NSCLC spatial transcriptome, single-cell transcriptome, T-cell receptor repertoire sequencing, bulk RNA transcriptome, phosphorylated proteome, genome mutation, and clinical data were included for a comprehensive assessment of the therapeutic and prognostic impact of HIF1A+ CSF3R+ neutrophils in NSCLC. In vitro experiments validated the functional phenotype of HIF1A+ CSF3R+ neutrophils and co-localization interactions with other cellular subpopulations. Gradient boosting machine (GBM) constructed region of interest (ROI) models for evaluation. Computer-aided drug design (CADD) was used to predict targeted small molecule drugs, and in vivo mouse models were constructed to assess the effectiveness of the combination treatment regimen. RESULTS: Centered on HIF1A+ CSF3R+ neutrophils, recruited exhausted T cells and stromal cells form a hypoxic niche within the tumor region, which was enriched in non-response patients. ROI composed of these specific cellular subpopulations, associated with senescence and glycolysis, accurately predicting NSCLC progression, prognosis, and microenvironment composition. CADD analysis identified that platycodin-D2 specifically targeted CSF3R, reducing HIF1A expression and inhibiting neutrophil activity. Combining navitoclax, platycodin-D2 with anti-programmed cell death protein 1 (PD-1) significantly suppressed tumor proliferation and improved the immunosuppressive microenvironment. CONCLUSION: Our study emphasized the role of HIF1A+ CSF3R+ neutrophils in immunotherapeutic resistance of NSCLC, constructed a microenvironmental immune dysregulation network in a hypoxic ecological niche with HIF1A+ CSF3R+ neutrophils as the center. Platycodin-D2 specifically targeted HIF1A+ CSF3R+ neutrophils, enhancing the efficacy of anti-PD-1 therapy in NSCLC.
Humans↗
Bringing prosthetics into the 21st century.
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Artificial Limbs↗
A computer-aided interactive procedure to improve nurse-training programmes.
Nurses represent the largest single resource in terms of numbers of staff employed as well as the revenue cost within the National Health Service. As trainee nurses constitute about 30% of the nursing staff and in some cases provide more than 60% of the bedside care, the effective design of nurse training programmes must receive considerable analytic attention. A computer-aided interactive procedure is described which enables senior nursing administrators to evaluate and improve, from service point of view, a given nurse training programme.
Computers↗
Evaluation of computer-aided monitoring of patients after heart surgery.
The medical and economic benefits of a computer-aided monitoring system were evaluated in a prospective, randomized study of 810 patients after open-heart surgery. The design of the study separated benefits of systematized postoperative care from benefits unique to the computer system and established measurable criteria by which computer-aided monitoring systems could be objectively evaluated. Criteria for comparison included the rapidity, safety, and smoothness of convalescence and time spent for various nursing activities. The study showed that the computer-aided monitoring system did not provide discernible medical benefits nor favorably affect nursing activities. Downtime of the system averaged 1 day per week. Reliability and accuracy of the system were inadequate and the benefit/cost ratio was low. Future development of computer-aided monitoring systems for open cardiac surgery should stress reliability, accuracy and relevance of the monitored measurements.
Cardiac Surgical Procedures↗
Preventable anesthesia mishaps: a study of human factors.
A modified critical-incident analysis technique was used in a retrospective examination of the characteristics of human error and equipment failure in anesthetic practice. The objective was to uncover patterns of frequently occurring incidents that are in need of careful prospective investigation. Forty-seven interviews were conducted with staff and resident anesthesiologists at one urban teaching institution, and descriptions of 359 preventable incidents were obtained. Twenty-three categories of details from these descriptions were subjected to computer-aided analysis for trends and patterns. Most of the preventable incidents involved human error (82 per cent), with breathing-circuit disconnections, inadvertent changes in gas flow, and drug-syringe errors being frequent problems. Overt equipment failures constituted only 14 per cent of the total number of preventable incidents, but equipment design was indictable in many categories of human error, as were inadequate experience and insufficient familiarity with equipment or with the specific surgical procedure. Other factors frequently associated with incidents were inadequate communication among personnel, haste or lack of precaution, and distraction. Results from multi-hospital studies based on the methodology developed could be used for more objective determination of priorities and planning of specific investments for decreasing the risk associated with anesthesia.
Accident Prevention↗
A physiological analysis of walking in the American lobster (Homarus americanus).
The normal, unrestrained, forward walking of the lobster was studied with a closed-circuit television system and a video-tape recorder. A frame-by-frame analysis was undertaken and measurements made of unilateral stepping sequences, contralateral and ipsilateral phase relations between pairs of legs, the movements at the leg joints primarily involved in stepping and their differences in each of the four pereiopods. The order of stepping was expressed in terms of the probability of any leg following any other leg and it was found that while there is a preferred order, there is considerable variation from the dominant pattern. The commonest deviations from the dominant gait are those involving the simplest types of re-ordering of the sequence. Pairs of contralateral legs show a strong tendency to alternate but all phase relations can occur. Similarly, while the ipsilateral legs show preferred phase relations, all possible relations do occur. The four pereiopods from anterior to posterior were found to have respectively, a pulling action, a combined pulling and rowing action, a rowing action and a combined pushing and rowing action. The same parameters of stepping were recorded from animals walking on a transparent, driven treadmill and, as no significant differences were found in comparisons with results from freely moving animals, subsequent results were obtained from animals walking on the treadmill where more detailed study and manipulation could readily be made. The stepping action of the third pereiopod during forwards walking involves major movements about two joints whereas the other pereiopods move about three joints. Detailed study of the intra-leg activity was therefore confined to the third pereiopod where the simpler action considerably simplified the problems involved in collecting and analysing data. Measurements were made of the angles swept out by the joints of the third pereiopod during movement. Electromyograms were recorded from the six muscles primarily responsible for these movements and from movement transducers placed at the joints. The duration of the movements and of the bursts of acitivity in the muscles and the interrelation between different muscle bursts were measured and a computer-aided analysis made to determine the characteristic features of the inter-burst relations during stepping. While there is considerable variability from step to step, the overall activity is relatively phase-constant over a wide range of stepping frequencies. When some of the key parameters of normal walking had been characterized, changes designed to alter the sensory input to the system were imposed.
Animals↗
[Mechanical studies on the dental bridges by the finite element method. (1)--An abutment tooth model-- (author's transl)].
Biomechanical considerations are very important to design a prosthetic appliance; however, there have been no satisfactory quantitative studies of such problems, mainly because theoretical and experimental models are unable to represent exactly the natural conditions in the mouth. The finite element method has been successfully applied in each field of applied mechanics and found to be effective for the structural analysis of the biological systems, for it has the advantage of greater versatility for modelling. Accordingly, this analytical, computer-aided method was applied to the dental bridges to evaluate the loads transmitted to the abutment tooth and the stress distributions in the supporting tissues. As the preliminary study a two-dimensional model was constructed to simulate the tooth subject to a vertical and a horizontal load and a moment at the coronal portion. The stress distributions in the tooth and the periodontal membrane and the force distributions on the socket wall were calculated for three load conditions. The tooth mobility and the center-of-rotation position were compared with actual data available in some literatures and the characteristics of tooth support were discussed in terms of three spring constants.
Dental Abutments↗
Computer-aided diagnosis of "dyspepsia".
Experience with computer-aided diagnosis of "dyspepsia" in a consecutive prospective series of 212 patients coming to surgery is described. Analysis is concentrated upon 122 patients who presented to an outpatient clinic de novo for diagnosis. During their first (outpatient) hospital contact, a firm diagnosis was made in just over half of these patients (though where made, it was usually correct). After full investigation, the diagnostic accuracy (prior to operation) was 92.6%. Using data elicited solely from the house surgeon's interview at the time of admission, the computer's overall diagnostic accuracy was 87.7%. The cost of each new computer diagnosis was around 25 new pence ($0.60). and the time taken was about 5 minutes. In a further small series designed to discriminate between organic and functional dyspepsia, the computer correctly assigned all but 1 of 23 patients with organic disease to the correct disease category. However, almost half of 33 patients with x-ray negative dyspepsia were predicted by the computer to have organic lesions. Time alone will tell whether the computer is a better early predictor of eventual organic disease than currently available radiologic methods.
Bayes Theorem↗
Bayesian statistics: a guided tour.
An overview of Bayesian statistical decision theory is presented in the tutorial spirit. A section on fundamental principles is followed by selected applications of the Bayesian approach to parameter estimation, pattern recognition, image processing, computer-aided medical diagnosis, optimal diagnostic test selection, and radiotherapy treatment planning.
Decision Making↗