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1.  Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models 
PLoS ONE  2014;9(4):e93535.
This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.
doi:10.1371/journal.pone.0093535
PMCID: PMC3979699  PMID: 24714065
2.  The Real Code of Leonardo da Vinci 
Current Cardiology Reviews  2008;4(1):60-62.
Leonardo da Vinci was born in Italy. Among the researchers and scientists, he is favourably known for his remarkable efforts in scientific work. His investigations of atherosclerosis judiciously combine three separate fields of research. In 1506, he finished his masterpiece, painting of Mona Lisa. A careful clinical examination of the famous painting reveals a yellow irregular leather-like spot at the inner end of the left upper eyelid and a soft bumpy well-defined swelling of the dorsum of the right hand beneath the index finger about 3 cm long. This is probably the first case of familial hypercholesterolemia (FH). The FH code of Leonardo da Vinci was given immense consideration by scientists like Carl Muller, who described the xanthomas tuberosum and angina pectoris. On the contrary, Akira Endo searched for microbial metabolites that would inhibit HMG-CoA reductase, the rate-limiting enzyme in the synthesis of cholesterol and finally, Michael Brown and Joseph Goldstein published a remarkable series of elegant and insightful papers in the 70s and 80s. They established that the cellular uptake of low-density lipoprotein (LDL) essentially requires the LDL receptor. In conclusion: this was the real Code of Leonardo da Vinci.
doi:10.2174/157340308783565401
PMCID: PMC2774586  PMID: 19924278
Familial hypercholesterolemia; Leonardo da Vinci.
3.  On the trail of Leonardo 
A night course taken almost 25 years ago sparked an interest in Leonardo da Vinci that has become a passion for a London, Ont., neurosurgeon. Dr. Rolando Del Maestro now boasts one of the largest collections of da Vinci artifacts in North America.
PMCID: PMC1229105  PMID: 9538858
4.  Microbiological Analysis of Surfaces of Leonardo Da Vinci's Atlantic Codex: Biodeterioration Risk 
Following the discovery of discoloration on some pages of the Atlantic Codex (AC) of Leonardo da Vinci kept in the Biblioteca Ambrosiana in Milan, some investigations have been carried out to verify the presence of microorganisms, such as bacteria and fungi. To verify the presence of microorganisms a noninvasive method of sampling has been used that was efficient and allowed us to highlight the microbial facies of the material that was examined using conventional microbiological techniques. The microclimatic conditions in the storage room as well as the water content of the volume were also assessed. The combined observations allowed the conclusion that the discoloration of suspected biological origin on some pages of AC is not related to the presence or current attack of microbial agents.
doi:10.1155/2014/214364
PMCID: PMC4276117  PMID: 25574171
5.  Leonardo da Vinci and the origin of semen 
It is well known that Leonardo da Vinci made several drawings of the human male anatomy. The early drawings (before 1500) were incorrect in identifying the origin of semen, where he followed accepted teaching of his time. It is widely thought that he did not correct this mistake, a view that is reflected in several biographies. In fact, he made a later drawing (after 1500) in which the description of the anatomy is remarkably accurate and must have been based on careful dissection. In addition to highlighting this fact, acknowledged previously in only one other source, this article reviews the background to Leonardo's knowledge of the relevant anatomy.
doi:10.1098/rsnr.2014.0021
PMCID: PMC4213433  PMID: 27494016
Leonardo da Vinci; semen; male anatomy
6.  Amid the possible causes of a very famous foxing: molecular and microscopic insight into Leonardo da Vinci's self‐portrait 
Summary
Leonardo da Vinci's self‐portrait is affected by foxing spots. The portrait has no fungal or bacterial infections in place, but is contaminated with airborne spores and fungal material that could play a role in its disfigurement. The knowledge of the nature of the stains is of great concern because future conservation treatments should be derived from scientific investigations. The lack of reliable scientific data, due to the non‐culturability of the microorganisms inhabiting the portrait, prompted the investigation of the drawing using non‐invasive and micro‐invasive sampling, in combination with scanning electron microscope (SEM) imaging and molecular techniques. The fungus E urotium halophilicum was found in foxing spots using SEM analyses. Oxalates of fungal origin were also documented. Both findings are consistent with the hypothesis that tonophilic fungi germinate on paper metabolizing organic acids, oligosaccharides and proteic compounds, which react chemically with the material at a low water activity, forming brown products and oxidative reactions resulting in foxing spots. Additionally, molecular techniques enabled a screening of the fungi inhabiting the portrait and showed differences when different sampling techniques were employed. Swabs samples showed a high abundance of lichenized Ascomycota, while the membrane filters showed a dominance of A cremonium sp. colonizing the drawing.
doi:10.1111/1758-2229.12313
PMCID: PMC4959533  PMID: 26111623
7.  The trabecula septomarginalis (Leonardo’s cord) in abnormal ventriculo-arterial connections: anatomic and morphogenetic implications 
Background
The abnormal ventriculo-arterial connections in atrio-ventricular concordance and situs solitus with two well developed ventricles include the range from tetralogy of Fallot throughout the different forms of double outlet right ventricle to transposition of great arteries.
The infundibular septum and the trabecula septomarginalis are the fundamental anatomical landmarks for the segmental analysis.
In these abnormalities there is a pathological progressive counter-clockwise rotation of the infundibular septum which divorces from the antero-superior limb of the trabecula septomarginalis and achieves his identity. Is there any anatomical evidence of a simultaneous abnormal counter-clockwise rotation of the trabecula septomarginalis?
Methods
Malposition of great arteries is a generic term since all relationships have to be expected.
We present specimens with anatomical evidence of a progressive counter-clockwise rotation from 0° to about 180°of the plane passing throughout the trabecula septomarginalis’s limbs.
Results
We can observe sequentially:
1. Malformations in which the posterior limb of the trabecula septomarginalis is committed to the ventriculo infundibular fold: (tetralogy of Fallot, double outlet right ventricle with sub-aortic ventricular septal defect, truncus arteriosus and doubly committed ventricular septal defect);
2. Malformations in which the posterior limb of the trabecula septomarginalis is committed to the infundibular septum (double outlet right ventricle with sub-pulmonary ventricular septal defect, transposition of great arteries).
Conclusions
1. The sequential-segmental analysis identify all the morphologies.
2. The trabecula septomarginalis plane presents a progressive counter-clockwise twist on the long axis.
3. Since the trabeculated portions of the ventricles are the oldest developmental components, our observations support the hypothesis that the abnormal ventriculo-arterial connections could be in relation with a pathological myocardial process during early cardio-genesis.
We are promoting new studies to investigate our anatomical observations.
doi:10.1186/1749-8090-9-71
PMCID: PMC4014757  PMID: 24750982
Ventriculo-arterial connections; Trabecula septomarginalis; Infundibular septum; Ventricular septum; Ventriculo-infundibular fold
8.  Leonardo Zamudio Villanueva 
International Orthopaedics  2013;37(12):2545-2546.
doi:10.1007/s00264-013-2119-7
PMCID: PMC3843187  PMID: 24122046
11.  International Symposium on Leonardo da Vinci 
Medical History  1966;10(3):294-295.
PMCID: PMC1033613
15.  Leonardo da Vinci's views on arteriosclerosis. 
Medical History  1973;17(3):304-308.
Images
PMCID: PMC1081478  PMID: 4601167
16.  First International Conference between West and East—Leonardo and Lao-Tze. Western Science Meets Eastern Wisdom. Experiences of Scientists and Intellectuals for the Creation of a New Paradigm of Modern Science 
The Conference was organized and supported by: Nei Dan School (European School of Internal Martial Arts), NIB (Laboratory of Molecular Biology and Stem Cell Bioengineering, National Institute of Biostructures and Biosystems, Institute of Cardiology, S.Orsola-Malpighi Hospital, Bologna), WACIMA (Worldwide Association Chinese Internal Martial Arts), Arti D’Oriente (Magazine of Eastern culture and traditions), Nuovo Orizzonte (Taiji Quan School in Florence), Samurai (Journal on Martial Arts), and Pinus (First National Institute for the Unification of Medical Strategies). Nei Dan School (www.taichineidan.com, neidan@libero.it) was in charge of the organization. Future meetings of the Centro studi ‘Tao and Science’ will take place in spring 2007 in Firenze and in October 2007 in Bologna. For information: E-mail: neidan@libero.it; web site: www.taichineidan.com, www.taoandscience.com
doi:10.1093/ecam/nem039
PMCID: PMC2249746  PMID: 18317548
east and west; neuroscience; modern science; Taiji
21.  Anatomy and Leonardo da Vinci. 
Images
PMCID: PMC2588719  PMID: 11501715
23.  LEONARDO THE ANATOMIST 
California Medicine  1956;84(5):374.
PMCID: PMC1531832
24.  Leonardo Da Vinci 
PMCID: PMC1822503  PMID: 14945040
25.  LEONARDO DA VINCI'S INFLUENCE ON RENAISSANCE ANATOMY 
Medical History  1964;8(4):360-370.
PMCID: PMC1033412  PMID: 14230140

Results 1-25 (451)