Z. Georgiev - Academia.edu (original) (raw)

Papers by Z. Georgiev

Research paper thumbnail of Immunohistochemical study on antigen-presenting cells in healthy and carious human teeth

Bratislava Medical Journal, 2018

Class II major histocompatibility complex (MHC) antigen-presenting cells are associated with the ... more Class II major histocompatibility complex (MHC) antigen-presenting cells are associated with the early phase of the immune response. We have studied the distribution of class II-expressing cells in developing, healthy and carious human teeth to clarify, when human pulp acquires an immunologic defense potential and how this reacts to dental caries. Antigen-expressing cells were identifi ed immunohistochemically with the following monoclonal antibodies: HLA-DR-for dendritic cells and CD68-for macrophages. In the pulp of unerupted developing teeth, HLA-DR-positive cells were distributed mainly in and around the odontoblast layer. A few CD68 positive cells were located more coronary around the blood vessels. In erupted teeth, HLA-DR-positive cells were located, for the most part, just beneath the odontoblast layer. CD68 positive cells were also located coronary, mainly around the blood vessels. Superfi cial caries lesions caused an aggregation of HLA-DR-positive cells and macrophages in the dental pulp corresponding to the lesion. These fi ndings showed that: (1) human teeth are already equipped with an immunological defense potential prior to eruption; (2) in the initial stage of caries infection, an immuno-response mediated by class-II-expressing cells is initiated in human dental pulp (Fig. 8, Ref. 33).

Research paper thumbnail of Time-Controlled and FinFET Compatible Sub-Bandgap References using Bulk-Diodes

IEEE Transactions on Circuits and Systems II: Express Briefs, 2019

This brief presents an innovative technique for precise reference generation based on “digital-al... more This brief presents an innovative technique for precise reference generation based on “digital-alike” operation. The bias of pn-junctions is defined trough pulse timings, while respective PTAT and CTAT signals are sampled from the voltage-decay of a capacitor. The greatly simple structures offer intrinsic supply robustness and use charge sharing or addition, to achieve large reverse-bandgap levels. Here, we employ the bulk-to-substrate diode of any baseline process combined with charge-pump function, instead of BJT devices. Two different circuit ideas were designed in 16-nm FinFET, with ultra-low power requirements. The first version achieves an untrimmed <inline-formula> <tex-math notation="LaTeX">$3\sigma $ </tex-math></inline-formula>-accuracy of ±0.82%, realizing 235-mV reference output down to 0.85-V supply. A second IP carries lowest complexity using a single diode only: it consumes 21 nA at <inline-formula> <tex-math notation="LaTeX">$1680~\mu \text{m}^{2}$ </tex-math></inline-formula> active area, and provides larger levels of Vref ~370 mV at merely ±2.7 mV total spread from silicon data. Unlike prior art, the compact reverse bandgaps do not require typical analog structures, like resistors, matched biasing, or differential amplifiers.

Research paper thumbnail of Evaluation of buffer capa city of saliva in caries-free and caries-active children

Prilozi / Makedonska akademija na naukite i umetnostite, Oddelenie za biološki i medicinski nauki = Contributions / Macedonian Academy of Sciences and Arts, Section of Biological and Medical Sciences, 2013

The aim of this study was to evaluate the relationship between the physicochemical properties of ... more The aim of this study was to evaluate the relationship between the physicochemical properties of saliva, such as buffering capacity, in caries-free and caries-active children. Eighty children aged 12-14 years were included in this study. They were divided into two groups: a caries-free and a caries-active group, with 40 children in each group. Material for biochemical testing of saliva - a sample was taken from all subjects at different time intervals: 5, 30 and 60 minutes after the daily meal. The examined parameters were followed in the same examinees in a sample of saliva taken in the morning before consuming any food or implementation of oral hygiene: they represent basic information compared with the results of the examination. The concentration of salivary bicarbonates was determined by the enzyme method of continuous measurement. Salivary concentration of bicarbonates, measured fasting in the morning (basic values) in the caries-free group, ranging in limits from 6.60 to 9.70...

Research paper thumbnail of Immunohistochemical study on antigen-presenting cells in healthy and carious human teeth

Bratislava Medical Journal, 2018

Class II major histocompatibility complex (MHC) antigen-presenting cells are associated with the ... more Class II major histocompatibility complex (MHC) antigen-presenting cells are associated with the early phase of the immune response. We have studied the distribution of class II-expressing cells in developing, healthy and carious human teeth to clarify, when human pulp acquires an immunologic defense potential and how this reacts to dental caries. Antigen-expressing cells were identifi ed immunohistochemically with the following monoclonal antibodies: HLA-DR-for dendritic cells and CD68-for macrophages. In the pulp of unerupted developing teeth, HLA-DR-positive cells were distributed mainly in and around the odontoblast layer. A few CD68 positive cells were located more coronary around the blood vessels. In erupted teeth, HLA-DR-positive cells were located, for the most part, just beneath the odontoblast layer. CD68 positive cells were also located coronary, mainly around the blood vessels. Superfi cial caries lesions caused an aggregation of HLA-DR-positive cells and macrophages in the dental pulp corresponding to the lesion. These fi ndings showed that: (1) human teeth are already equipped with an immunological defense potential prior to eruption; (2) in the initial stage of caries infection, an immuno-response mediated by class-II-expressing cells is initiated in human dental pulp (Fig. 8, Ref. 33).

Research paper thumbnail of Time-Controlled and FinFET Compatible Sub-Bandgap References using Bulk-Diodes

IEEE Transactions on Circuits and Systems II: Express Briefs, 2019

This brief presents an innovative technique for precise reference generation based on “digital-al... more This brief presents an innovative technique for precise reference generation based on “digital-alike” operation. The bias of pn-junctions is defined trough pulse timings, while respective PTAT and CTAT signals are sampled from the voltage-decay of a capacitor. The greatly simple structures offer intrinsic supply robustness and use charge sharing or addition, to achieve large reverse-bandgap levels. Here, we employ the bulk-to-substrate diode of any baseline process combined with charge-pump function, instead of BJT devices. Two different circuit ideas were designed in 16-nm FinFET, with ultra-low power requirements. The first version achieves an untrimmed <inline-formula> <tex-math notation="LaTeX">$3\sigma $ </tex-math></inline-formula>-accuracy of ±0.82%, realizing 235-mV reference output down to 0.85-V supply. A second IP carries lowest complexity using a single diode only: it consumes 21 nA at <inline-formula> <tex-math notation="LaTeX">$1680~\mu \text{m}^{2}$ </tex-math></inline-formula> active area, and provides larger levels of Vref ~370 mV at merely ±2.7 mV total spread from silicon data. Unlike prior art, the compact reverse bandgaps do not require typical analog structures, like resistors, matched biasing, or differential amplifiers.

Research paper thumbnail of Evaluation of buffer capa city of saliva in caries-free and caries-active children

Prilozi / Makedonska akademija na naukite i umetnostite, Oddelenie za biološki i medicinski nauki = Contributions / Macedonian Academy of Sciences and Arts, Section of Biological and Medical Sciences, 2013

The aim of this study was to evaluate the relationship between the physicochemical properties of ... more The aim of this study was to evaluate the relationship between the physicochemical properties of saliva, such as buffering capacity, in caries-free and caries-active children. Eighty children aged 12-14 years were included in this study. They were divided into two groups: a caries-free and a caries-active group, with 40 children in each group. Material for biochemical testing of saliva - a sample was taken from all subjects at different time intervals: 5, 30 and 60 minutes after the daily meal. The examined parameters were followed in the same examinees in a sample of saliva taken in the morning before consuming any food or implementation of oral hygiene: they represent basic information compared with the results of the examination. The concentration of salivary bicarbonates was determined by the enzyme method of continuous measurement. Salivary concentration of bicarbonates, measured fasting in the morning (basic values) in the caries-free group, ranging in limits from 6.60 to 9.70...