This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
International Journal of Molecular Sciences, Dec 14, 2020
Evaluating agent intelligence is a fundamental issue for the understanding, construction and impr... more Evaluating agent intelligence is a fundamental issue for the understanding, construction and improvement of autonomous agents. New intelligence tests have been recently developed based on an assessment of task complexity using algorithmic information theory. Some early experimental results have shown that these intelligence tests may be able to distinguish between agents of the same kind, but they do not place very different agents, e.g., humans and machines, on a correct scale. It has been suggested that a possible explanation is that these tests do not measure social intelligence. One formal approach to incorporate social environments in an intelligence test is the recent notion of Darwin-Wallace distribution. Inspired by this distribution we present several new test settings considering competition and cooperation, where we evaluate the "social intelligence" of several reinforcement learning algorithms. The results show that evaluating social intelligence raises many issues that need to be addressed in order to devise tests of social intelligence.
the π/A hysteresis and of the elastic process contribution to π relaxation transients. Thus, MGS ... more the π/A hysteresis and of the elastic process contribution to π relaxation transients. Thus, MGS films of mammals with similar blinking frequency and TF stability have similar surface properties and stress relaxations unaltered by the interspecies MGS compositional variations. Such knowledge may impact the selection of animal mimics of human MGS and on a better understanding of lipid classes' impact on meibum functionality.
The biological half-life and final residue levels of buprofezin and teflubenzuron were examined i... more The biological half-life and final residue levels of buprofezin and teflubenzuron were examined in peaches over a 14-day cultivation period. The residue levels of buprofezin and teflubenzuron were analyzed by chromatographic method with recovery ranging from 84.0% to 96.6%. The biological half-lives of buprofezin and teflubenzuron were 4.88 and 11.49 days at the standard dose, and 4.40 and 10.86 days at a triple dose, respectively. The initial concentration of buprofezin exceeded the maximum residue limit (MRL) set in Korea, but the concentration decreased to below the MRL within 6 days after application. The initial and persisting concentrations of teflubenzuron were all below the prescribed MRL. The final residue levels of buprofezin and teflubenzuron were 0.17 and 0.10 mg•kg −1 following a standard single dose, and 0.20 and 0.23 mg•kg −1 following a triple dose, respectively. The final residue levels of buprofezin and teflubenzuron were also compared with the good agricultural practices standards of the United States and Italy.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
In a recent study, (Ewurum et al., 2021) wax (WE) and sterol esters (CE) from human meibum secret... more In a recent study, (Ewurum et al., 2021) wax (WE) and sterol esters (CE) from human meibum secretions (MGS) were separated and reconstituted with controlled WE/CE ratios (0%, 20%, 30%, 40%, 50%, 75% and 100% CE weight fractions). It was found that the alterations in the CE content of WE/CE mixtures modified the hydrocarbon chain conformation and packing of the mixture. A major question that emerges is whether the spectroscopic packing parameters determined for bulk meibum translate to a change in the performance of meibomian layers at the air/water interface, as it is the surface film functionality that is crucial for the performance of MGS at the ocular surface. The study of human meibum films with Langmuir surface balance was performed to access the surface properties at blink-like deformations of the film area. Surface pressure (π)-area (A) isocycles and stress relaxations were used to assess the layer's reorganization during area cycling and dilatational elasticity, respectively. The morphology of the films was monitored by Brewster angle microscopy. It was found that the increased order and chain melting temperature of the bulk samples correlated with a raise in the maximum surface pressure attained at minimal surface area and in the transient dilatational modulus of the meibomian layers. Such correlations may allow for development of an improved understanding between the bulk and surface properties of human meibum and of other natural and synthetic tear lipid films.
International Journal of Molecular Sciences, Jul 28, 2018
Elevated levels of acyl chain saturation of meibomian lipids are associated with vastly different... more Elevated levels of acyl chain saturation of meibomian lipids are associated with vastly different effects: from enhanced tear film (TF) stability in infants to shortened TF breakup time in meibomian gland disease patients. Thus it is important to study the effect of saturation on the surface properties of human meibum (MGS). Therefore, MGS films (1, 2, 3, 4, 5, 10, 25, 50, 67, and 100% saturation) were spread at the air/water interface of a Langmuir surface balance. The layers' capability to reorganize during dynamic area changes was accessed via the surface pressure (π)-area (A) compression isotherms and step/relaxation dilatational rheology studies. Film structure was monitored with Brewster angle microscopy. The raise in the % (at ≥10%) of saturation resulted in the formation of stiffer, thicker, and more elastic films at π ≥ 12 mN/m with the effects being proportional to the saturation level. At the same time, at low (≤10 mN/m) π the raise in saturation resulted in altered spreading and heterogeneous structure of MGS layers. The strong impact of saturation on MGS surface properties correlates with our recent spectroscopy study, which demonstrated that saturation induced increase of MGS acyl chain order, phase transition temperature, and cooperativity.
Tear film lipid layer (TFLL) stabilizes the air/tear surface of the human eye. Meibomian gland dy... more Tear film lipid layer (TFLL) stabilizes the air/tear surface of the human eye. Meibomian gland dysfunction (MGD) resulting in quantitative and qualitative modifications of TFLL major (>93%) component, the oily secretion of meibomian lipids (MGS), is the world leading cause of dry eye syndrome (DES) with up to 86% of all DES patients showing signs of MGD. Caused by intrinsic factors (aging, ocular and general diseases) and by extrinsic everyday influences like contact lens wear and extended periods in front of a computer screen, DES (resulting in TF instability, visual disturbances and chronic ocular discomfort) is the major ophthalmic public health disease of the present time affecting the quality of life of 10e30% of the human population worldwide. Therefore there is a pressing need to summarize the present knowledge, contradictions and open questions to be resolved in the field of TFLL composition/structure/ functions relationship. The following major aspects are covered by the review: (i) Do we have a reliable mimic for TFLL: MGS vs contact lens lipid extracts (CLLE) vs lipid extracts from whole tears. Does TFLL truly consist of lipids only or it is important to keep in mind the TF proteins as well?; (ii) Structural properties of TFLL and of its mimics in health and disease in vitro and in vivo. How the TFLL uniformity and thickness ensures the functionality of the lipid layer (barrier to evaporation, surface properties, TF stability etc.); (iii) What are the main functions of the TFLL? In this aspect an effort is done to emphasize that there is no single main function of TFLL but instead it simultaneously fulfills plethora of functions: suppresses the evaporation (alone or probably in cooperation with other TF constituents) of the aqueous tears; stabilizes (due to its surface properties) the air/tear surface at eye opening and during the interblink interval; and even acts as a first line of defense against bacterial invasion due to its detergency action on the bacterial membranes. An effort is done to highlight how the concept on the importance of TFLL and TF viscoelasticity transpires from old and new studies and what are its clinical implications. An attempt is made to outline the future hot directions of research into the field ranging from quest for molecules that can significantly alter TFLL properties to addressing open questions on the contribution of TFLL to the overall performance of the TF.
PurposeTo evaluate (i) the mucomimeticity of pharmaceutically applicable hydrophilic polymers (HP... more PurposeTo evaluate (i) the mucomimeticity of pharmaceutically applicable hydrophilic polymers (HP) as well as (ii) their interactions with human meibum films.MethodsFour HP were used‐hyaluronic acid (HA), cross‐linked hyaluronic acid (CHA), carboxymethyl cellulose (CMC) and gellan gum (GG)‐ at the concentrations of 0.0001, 0.001,0.01,0.05, 0.1%. HP mucomimeticity was probed by the formation of tear‐like ferning patterns (TFP) after HP solution drop evaporation. The interactions between HP and meibum at the air/water interface were examined in vitro at blink‐like compression/expansion of the film area by Langmuir surface balance. Surface pressure (π)‐area (A) isocycles and stress relaxations were used to assess the sample’s lateral elasticity and reorganization during area cycling. Films morphology was monitored by Brewster Angle Microscopy (BAM).ResultsSignificant differences were observed in the capability of HP to form ferning patterns: CHA (≥0.001%) > HA (≥0.01%) = CMC (≥0.01%) > GG (≥0.05%). CHA, HA, CMC and GG enhanced the uniform spreading of meibomian layers as well as their elasticity and rapid reorganization at blink like area cycling in concentration dependent manner. BAM micrographs revealed considerable thickening of the meibomian films in the presence of HP.ConclusionsThe combination of tear ferning and Langmuir surface balance studies allows to simultaneously evaluate the mucomimetic and the lipid interaction properties of HP. TFP forming polymers enhanced both (i) the uniform spreading and structure of meibomian layers and (ii) their dynamic surface properties. Cross‐linking HA was particularly efficient both in ferning pattern and meibomian film systems.
International Journal of Molecular Sciences, Jul 12, 2019
Elevated levels of acyl chain saturation of meibomian lipids are associated with enhanced tear fi... more Elevated levels of acyl chain saturation of meibomian lipids are associated with enhanced tear film (TF) stability in infants to shortened TF breakup time with meibomian gland dysfunction. Thus, the effect of saturation on the surface properties of human TF lipids (TFLs) using a Langmuir surface balance and Brewster angle microscopy was studied. Lipid phase transitions were measured using infrared spectroscopy. The raise in the % of saturation resulted in thicker, and more elastic films at π = 12 mN/m, with the effects being proportional to the saturation level. At the same time, at lower (≤10 mN/m) π, the raise in saturation resulted in an altered spreading and modified structure of TFL layers. The strong impact of saturation on TFL surface properties correlated with a saturation induced increase of the TFL acyl chain order, phase transition temperature, and lipid-lipid interactions. The native TFL order and π max were significantly greater, compared with native meibum collected from the same individual. Aggregation of lipids on the tear surface due to saturation was not as significant as it was for meibum. Although the surface pressure/area isotherms for TFL were similar for meibum, differences in rheology and phase transition parameters warrant the study of both.
To assess and compare short-term visual and optical quality and tear film stability between two d... more To assess and compare short-term visual and optical quality and tear film stability between two dual-focus (DF) prototype myopia control contact lenses (CLs) having different inner zone diameters. Methods: Twenty-eight myopic subjects were included in this randomised, double-masked crossover study. Refraction, best-corrected visual acuity (VA) and tear film stability were measured at baseline (i.e., when uncorrected). Subjects were then binocularly fitted with the DF CLs, with only the sensorial dominant eye being assessed. Lenses were of the same material and had inner zone diameters of either 2.1 mm (S design) or 4.0 mm (M design). Visual and physical short-term lens comfort, over-refraction, best-corrected VA, stereopsis at 40 cm, best-corrected photopic and mesopic contrast sensitivity (CS), size and shape of light disturbance (LD), wavefront aberrations, subjective quality of vision (QoV Questionnaire) and tear film stability were measured for each lens. Results: Both CL designs decreased tear film stability compared with baseline (p < 0.05). VA and photopic CS were within normal values for the subjects' age with each CL. When comparing lenses, the M design promoted better photopic CS for the 18 cycles per degree spatial frequency (p < 0.001) and better LD (p < 0.02). However, higher-order aberrations were improved with the S design (p = 0.02). No significant difference between the two CLs was found for QoV scores and tear film stability. Conclusions: Both DF CLs provided acceptable visual performance under photopic conditions. The 4.0 mm inner zone gave better contrast sensitivity at high frequencies and lower light disturbance, while the 2.1 mm central diameter induced fewer higher-order aberrations for a 5 mm pupil diameter. Both CLs produced the same subjective visual short-term lens comfort.
Alumina Toughened Zirconia (ATZ) combining the toughness of alumina with the durability of zircon... more Alumina Toughened Zirconia (ATZ) combining the toughness of alumina with the durability of zirconia are promising implant materials. The topography and wettability, i.e. major bioactivity determinants, of ATZ surfaces were enhanced by femtosecond-laser biomimetic texturing.
Osteodegenerative diseases are one of the main reasons for pain and impaired movement in adult an... more Osteodegenerative diseases are one of the main reasons for pain and impaired movement in adult animals. That provokes scientists and physicians to research successful and safe treatment with long last effect, witch may improve condition of the affected animals. The therapy with autologus, mesenchymal stem cells may be a new promising treatment that has a potential to change the progess of the disease.
The treatment with mesenchymal stem cells has proved to be effective in the field of regenerative... more The treatment with mesenchymal stem cells has proved to be effective in the field of regenerative medicine, especially regarding osteodegenerative diseases. Clinical efficiency of that treatment takes place due to the ability of adipose tissue derived mesenchymal stem cells (MSC) to differentiate into chondroblasts and to modulate immune system via interactions with certain cell populations. The emerging new data give rise to other possible implementation of MSC, such as treatment of spinal chord injuries and chronic renal failure. In this article we try to summarize the recent data in the fast developing field of MSC treatment. We also present a clinical case report of autologous mesenchymal stem cells transplantation in a 13 years old dog with osteoarthritis.
Parvoviruses represent the most important infectious agents that are responsible for severe to fa... more Parvoviruses represent the most important infectious agents that are responsible for severe to fatal disease in carnivores. This study reports the results of a 10-year molecular survey conducted on carnivores in Bulgaria (n = 344), including 262 dogs and 19 cats with gastroenteritis, and 57 hunted wild carnivores. Real-time polymerase chain reaction (qPCR), followed by virus characterization by minor groove binder (MGB) probe assays, detected 216 parvovirus positive dogs with a predominance of canine parvovirus type 2a (CPV-2a, 79.17%) over CPV-2b (18.52%) and CPV-2c (2.31%). Rottweilers and German shepherds were the most frequent breeds among CPV-positive pedigree dogs (n = 96). Eighteen cats were found to shed parvoviruses in their faeces, with most strains being characterized as FPLV (n = 17), although a single specimen tested positive for CPV-2a. Only two wild carnivores were parvovirus positive, a wolf (Canis lupus) and a red fox (Vulpes vulpes), both being infected by CPV-2a strains.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
International Journal of Molecular Sciences, Dec 14, 2020
Evaluating agent intelligence is a fundamental issue for the understanding, construction and impr... more Evaluating agent intelligence is a fundamental issue for the understanding, construction and improvement of autonomous agents. New intelligence tests have been recently developed based on an assessment of task complexity using algorithmic information theory. Some early experimental results have shown that these intelligence tests may be able to distinguish between agents of the same kind, but they do not place very different agents, e.g., humans and machines, on a correct scale. It has been suggested that a possible explanation is that these tests do not measure social intelligence. One formal approach to incorporate social environments in an intelligence test is the recent notion of Darwin-Wallace distribution. Inspired by this distribution we present several new test settings considering competition and cooperation, where we evaluate the "social intelligence" of several reinforcement learning algorithms. The results show that evaluating social intelligence raises many issues that need to be addressed in order to devise tests of social intelligence.
the π/A hysteresis and of the elastic process contribution to π relaxation transients. Thus, MGS ... more the π/A hysteresis and of the elastic process contribution to π relaxation transients. Thus, MGS films of mammals with similar blinking frequency and TF stability have similar surface properties and stress relaxations unaltered by the interspecies MGS compositional variations. Such knowledge may impact the selection of animal mimics of human MGS and on a better understanding of lipid classes' impact on meibum functionality.
The biological half-life and final residue levels of buprofezin and teflubenzuron were examined i... more The biological half-life and final residue levels of buprofezin and teflubenzuron were examined in peaches over a 14-day cultivation period. The residue levels of buprofezin and teflubenzuron were analyzed by chromatographic method with recovery ranging from 84.0% to 96.6%. The biological half-lives of buprofezin and teflubenzuron were 4.88 and 11.49 days at the standard dose, and 4.40 and 10.86 days at a triple dose, respectively. The initial concentration of buprofezin exceeded the maximum residue limit (MRL) set in Korea, but the concentration decreased to below the MRL within 6 days after application. The initial and persisting concentrations of teflubenzuron were all below the prescribed MRL. The final residue levels of buprofezin and teflubenzuron were 0.17 and 0.10 mg•kg −1 following a standard single dose, and 0.20 and 0.23 mg•kg −1 following a triple dose, respectively. The final residue levels of buprofezin and teflubenzuron were also compared with the good agricultural practices standards of the United States and Italy.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
In a recent study, (Ewurum et al., 2021) wax (WE) and sterol esters (CE) from human meibum secret... more In a recent study, (Ewurum et al., 2021) wax (WE) and sterol esters (CE) from human meibum secretions (MGS) were separated and reconstituted with controlled WE/CE ratios (0%, 20%, 30%, 40%, 50%, 75% and 100% CE weight fractions). It was found that the alterations in the CE content of WE/CE mixtures modified the hydrocarbon chain conformation and packing of the mixture. A major question that emerges is whether the spectroscopic packing parameters determined for bulk meibum translate to a change in the performance of meibomian layers at the air/water interface, as it is the surface film functionality that is crucial for the performance of MGS at the ocular surface. The study of human meibum films with Langmuir surface balance was performed to access the surface properties at blink-like deformations of the film area. Surface pressure (π)-area (A) isocycles and stress relaxations were used to assess the layer's reorganization during area cycling and dilatational elasticity, respectively. The morphology of the films was monitored by Brewster angle microscopy. It was found that the increased order and chain melting temperature of the bulk samples correlated with a raise in the maximum surface pressure attained at minimal surface area and in the transient dilatational modulus of the meibomian layers. Such correlations may allow for development of an improved understanding between the bulk and surface properties of human meibum and of other natural and synthetic tear lipid films.
International Journal of Molecular Sciences, Jul 28, 2018
Elevated levels of acyl chain saturation of meibomian lipids are associated with vastly different... more Elevated levels of acyl chain saturation of meibomian lipids are associated with vastly different effects: from enhanced tear film (TF) stability in infants to shortened TF breakup time in meibomian gland disease patients. Thus it is important to study the effect of saturation on the surface properties of human meibum (MGS). Therefore, MGS films (1, 2, 3, 4, 5, 10, 25, 50, 67, and 100% saturation) were spread at the air/water interface of a Langmuir surface balance. The layers' capability to reorganize during dynamic area changes was accessed via the surface pressure (π)-area (A) compression isotherms and step/relaxation dilatational rheology studies. Film structure was monitored with Brewster angle microscopy. The raise in the % (at ≥10%) of saturation resulted in the formation of stiffer, thicker, and more elastic films at π ≥ 12 mN/m with the effects being proportional to the saturation level. At the same time, at low (≤10 mN/m) π the raise in saturation resulted in altered spreading and heterogeneous structure of MGS layers. The strong impact of saturation on MGS surface properties correlates with our recent spectroscopy study, which demonstrated that saturation induced increase of MGS acyl chain order, phase transition temperature, and cooperativity.
Tear film lipid layer (TFLL) stabilizes the air/tear surface of the human eye. Meibomian gland dy... more Tear film lipid layer (TFLL) stabilizes the air/tear surface of the human eye. Meibomian gland dysfunction (MGD) resulting in quantitative and qualitative modifications of TFLL major (>93%) component, the oily secretion of meibomian lipids (MGS), is the world leading cause of dry eye syndrome (DES) with up to 86% of all DES patients showing signs of MGD. Caused by intrinsic factors (aging, ocular and general diseases) and by extrinsic everyday influences like contact lens wear and extended periods in front of a computer screen, DES (resulting in TF instability, visual disturbances and chronic ocular discomfort) is the major ophthalmic public health disease of the present time affecting the quality of life of 10e30% of the human population worldwide. Therefore there is a pressing need to summarize the present knowledge, contradictions and open questions to be resolved in the field of TFLL composition/structure/ functions relationship. The following major aspects are covered by the review: (i) Do we have a reliable mimic for TFLL: MGS vs contact lens lipid extracts (CLLE) vs lipid extracts from whole tears. Does TFLL truly consist of lipids only or it is important to keep in mind the TF proteins as well?; (ii) Structural properties of TFLL and of its mimics in health and disease in vitro and in vivo. How the TFLL uniformity and thickness ensures the functionality of the lipid layer (barrier to evaporation, surface properties, TF stability etc.); (iii) What are the main functions of the TFLL? In this aspect an effort is done to emphasize that there is no single main function of TFLL but instead it simultaneously fulfills plethora of functions: suppresses the evaporation (alone or probably in cooperation with other TF constituents) of the aqueous tears; stabilizes (due to its surface properties) the air/tear surface at eye opening and during the interblink interval; and even acts as a first line of defense against bacterial invasion due to its detergency action on the bacterial membranes. An effort is done to highlight how the concept on the importance of TFLL and TF viscoelasticity transpires from old and new studies and what are its clinical implications. An attempt is made to outline the future hot directions of research into the field ranging from quest for molecules that can significantly alter TFLL properties to addressing open questions on the contribution of TFLL to the overall performance of the TF.
PurposeTo evaluate (i) the mucomimeticity of pharmaceutically applicable hydrophilic polymers (HP... more PurposeTo evaluate (i) the mucomimeticity of pharmaceutically applicable hydrophilic polymers (HP) as well as (ii) their interactions with human meibum films.MethodsFour HP were used‐hyaluronic acid (HA), cross‐linked hyaluronic acid (CHA), carboxymethyl cellulose (CMC) and gellan gum (GG)‐ at the concentrations of 0.0001, 0.001,0.01,0.05, 0.1%. HP mucomimeticity was probed by the formation of tear‐like ferning patterns (TFP) after HP solution drop evaporation. The interactions between HP and meibum at the air/water interface were examined in vitro at blink‐like compression/expansion of the film area by Langmuir surface balance. Surface pressure (π)‐area (A) isocycles and stress relaxations were used to assess the sample’s lateral elasticity and reorganization during area cycling. Films morphology was monitored by Brewster Angle Microscopy (BAM).ResultsSignificant differences were observed in the capability of HP to form ferning patterns: CHA (≥0.001%) &gt; HA (≥0.01%) = CMC (≥0.01%) &gt; GG (≥0.05%). CHA, HA, CMC and GG enhanced the uniform spreading of meibomian layers as well as their elasticity and rapid reorganization at blink like area cycling in concentration dependent manner. BAM micrographs revealed considerable thickening of the meibomian films in the presence of HP.ConclusionsThe combination of tear ferning and Langmuir surface balance studies allows to simultaneously evaluate the mucomimetic and the lipid interaction properties of HP. TFP forming polymers enhanced both (i) the uniform spreading and structure of meibomian layers and (ii) their dynamic surface properties. Cross‐linking HA was particularly efficient both in ferning pattern and meibomian film systems.
International Journal of Molecular Sciences, Jul 12, 2019
Elevated levels of acyl chain saturation of meibomian lipids are associated with enhanced tear fi... more Elevated levels of acyl chain saturation of meibomian lipids are associated with enhanced tear film (TF) stability in infants to shortened TF breakup time with meibomian gland dysfunction. Thus, the effect of saturation on the surface properties of human TF lipids (TFLs) using a Langmuir surface balance and Brewster angle microscopy was studied. Lipid phase transitions were measured using infrared spectroscopy. The raise in the % of saturation resulted in thicker, and more elastic films at π = 12 mN/m, with the effects being proportional to the saturation level. At the same time, at lower (≤10 mN/m) π, the raise in saturation resulted in an altered spreading and modified structure of TFL layers. The strong impact of saturation on TFL surface properties correlated with a saturation induced increase of the TFL acyl chain order, phase transition temperature, and lipid-lipid interactions. The native TFL order and π max were significantly greater, compared with native meibum collected from the same individual. Aggregation of lipids on the tear surface due to saturation was not as significant as it was for meibum. Although the surface pressure/area isotherms for TFL were similar for meibum, differences in rheology and phase transition parameters warrant the study of both.
To assess and compare short-term visual and optical quality and tear film stability between two d... more To assess and compare short-term visual and optical quality and tear film stability between two dual-focus (DF) prototype myopia control contact lenses (CLs) having different inner zone diameters. Methods: Twenty-eight myopic subjects were included in this randomised, double-masked crossover study. Refraction, best-corrected visual acuity (VA) and tear film stability were measured at baseline (i.e., when uncorrected). Subjects were then binocularly fitted with the DF CLs, with only the sensorial dominant eye being assessed. Lenses were of the same material and had inner zone diameters of either 2.1 mm (S design) or 4.0 mm (M design). Visual and physical short-term lens comfort, over-refraction, best-corrected VA, stereopsis at 40 cm, best-corrected photopic and mesopic contrast sensitivity (CS), size and shape of light disturbance (LD), wavefront aberrations, subjective quality of vision (QoV Questionnaire) and tear film stability were measured for each lens. Results: Both CL designs decreased tear film stability compared with baseline (p < 0.05). VA and photopic CS were within normal values for the subjects' age with each CL. When comparing lenses, the M design promoted better photopic CS for the 18 cycles per degree spatial frequency (p < 0.001) and better LD (p < 0.02). However, higher-order aberrations were improved with the S design (p = 0.02). No significant difference between the two CLs was found for QoV scores and tear film stability. Conclusions: Both DF CLs provided acceptable visual performance under photopic conditions. The 4.0 mm inner zone gave better contrast sensitivity at high frequencies and lower light disturbance, while the 2.1 mm central diameter induced fewer higher-order aberrations for a 5 mm pupil diameter. Both CLs produced the same subjective visual short-term lens comfort.
Alumina Toughened Zirconia (ATZ) combining the toughness of alumina with the durability of zircon... more Alumina Toughened Zirconia (ATZ) combining the toughness of alumina with the durability of zirconia are promising implant materials. The topography and wettability, i.e. major bioactivity determinants, of ATZ surfaces were enhanced by femtosecond-laser biomimetic texturing.
Osteodegenerative diseases are one of the main reasons for pain and impaired movement in adult an... more Osteodegenerative diseases are one of the main reasons for pain and impaired movement in adult animals. That provokes scientists and physicians to research successful and safe treatment with long last effect, witch may improve condition of the affected animals. The therapy with autologus, mesenchymal stem cells may be a new promising treatment that has a potential to change the progess of the disease.
The treatment with mesenchymal stem cells has proved to be effective in the field of regenerative... more The treatment with mesenchymal stem cells has proved to be effective in the field of regenerative medicine, especially regarding osteodegenerative diseases. Clinical efficiency of that treatment takes place due to the ability of adipose tissue derived mesenchymal stem cells (MSC) to differentiate into chondroblasts and to modulate immune system via interactions with certain cell populations. The emerging new data give rise to other possible implementation of MSC, such as treatment of spinal chord injuries and chronic renal failure. In this article we try to summarize the recent data in the fast developing field of MSC treatment. We also present a clinical case report of autologous mesenchymal stem cells transplantation in a 13 years old dog with osteoarthritis.
Parvoviruses represent the most important infectious agents that are responsible for severe to fa... more Parvoviruses represent the most important infectious agents that are responsible for severe to fatal disease in carnivores. This study reports the results of a 10-year molecular survey conducted on carnivores in Bulgaria (n = 344), including 262 dogs and 19 cats with gastroenteritis, and 57 hunted wild carnivores. Real-time polymerase chain reaction (qPCR), followed by virus characterization by minor groove binder (MGB) probe assays, detected 216 parvovirus positive dogs with a predominance of canine parvovirus type 2a (CPV-2a, 79.17%) over CPV-2b (18.52%) and CPV-2c (2.31%). Rottweilers and German shepherds were the most frequent breeds among CPV-positive pedigree dogs (n = 96). Eighteen cats were found to shed parvoviruses in their faeces, with most strains being characterized as FPLV (n = 17), although a single specimen tested positive for CPV-2a. Only two wild carnivores were parvovirus positive, a wolf (Canis lupus) and a red fox (Vulpes vulpes), both being infected by CPV-2a strains.
Uploads
Papers by Petar Eftimov