Ultra-broadband high-resolution microdroplet spectrometers for the near infrared

By stabilizing the evaporation dynamics of a microliter fluorocarbon droplet, we demonstrate a fast-scan optofluidic Fourier transform (FT) spectrometer on the tip of an optical fiber operating in the 1000-2000 nm window with a resolution of 3.5 cm^-1 (i.e., <1 nm at 1560 nm). Compared with other FT near-infrared (NIR) small-scale spectrometers reported in the literature, the fluorocarbon droplet spectrometer shows the largest wavelength span and span/resolution ratio, allowing spectral analysis of broadband or narrowband radiation to be easily performed. Our results open the way for the practical application of droplet spectrometers as advanced optofluidic NIR analyzers with small size and low cost that are capable of operating in harsh environments, even in the absence of electrical power sources.

Outcomes and Stability of Anterior Open Bite Treatment with Skeletal Anchorage in Non-Growing Patients and Adults Compared to the Results of Orthognathic Surgery Procedures: A Systematic Review

The objective of this review is to evaluate, on the basis of the available literature, if anterior open bite (AOB) can be successfully treated with the intrusion of molar teeth using skeletal anchorage in non-growing patients and adults and if this treatment modality provides comparable results to those obtained by orthognathic surgery procedures.

METHODS

A systematic review of published data in major databases from 2000 to 2021 was performed.

RESULTS

In total, 92 articles were included in title and abstract screening, and only 16 articles (11 concerning AOB correction by molar intrusion with skeletal anchorage, and five considering AOB treatment by orthognathic surgical intervention) qualified for thorough data extraction and analysis.

CONCLUSIONS

On the basis of this review, it seems to be possible to obtain successful results for AOB treatment in non-growing patients and adults by means of the intrusion of molar teeth with skeletal anchorage. However, due to the different methods of assessing treatment outcomes used by different authors, it is not possible to state conclusively whether the treatment of AOB by means of molar intrusion with skeletal anchorage provides long-term results that are comparable to orthognathic surgery procedures.

Light pressure in droplet micro-resonators excited by free-space scattering

A droplet optical resonator is a unique environment to investigate light-matter interaction and optomechanics in liquids. Here, we report on light pressure effects derived from whispering gallery modes excited in a liquid-polymer droplet micro-resonator by free-space laser scattering. From the nonlinear resonance spectrum observed in the visible, we provide evidence of photon pressure exerted at the liquid-air boundary and quantify it with a coherent physical model. Our findings pave the way to studies on micro-rheology and nonlinear optofluidics, where droplets serve as miniature liquid laboratories.

A self-operating broadband spectrometer on a droplet

Small-scale Fourier transform spectrometers are rapidly revolutionizing infrared spectro-chemical analysis, enabling on-site and remote sensing applications that were hardly imaginable just few years ago. While most devices reported to date rely on advanced photonic integration technologies, here we demonstrate a miniaturization strategy which harnesses unforced mechanisms, such as the evaporation of a liquid droplet on a partially reflective substrate. Based on this principle, we describe a self-operating optofluidic spectrometer and the analysis method to retrieve consistent spectral information in spite of the intrinsically non-reproducible droplet formation and evaporation dynamics. We experimentally realize the device on the tip of an optical fiber and demonstrate quantitative measurements of gas absorption with a 2.6 nm resolution, in a 100 s acquisition time, over the 250 nm span allowed by our setup's components. A direct comparison with a commercial optical analyzer clearly points out that a simple evaporating droplet can be an efficient small-scale, inexpensive spectrometer, competitive with the most advanced integrated photonic devices.

Metallic skeletons as reinforcement of new composite materials applied in orthopaedics and dentistry

Purpose: The article concerns the development of completely new groups of composite materials that can be used to produce functional replacements for damaged bones or teeth. Design/methodology/approach: A selective laser sintering was used to produce the reinforcement of those materials from titanium and its Ti6Al4V alloy in the form of skeletons with pores with adjustable geometric features. The matrix of those materials is either air or crystallised from the liquid AlSi12 or AlSi7Mg0.3 alloys condition after prior vacuum infiltration or human osteoblast cells from the hFOB 1.19 (Human ATCC - CRL - 11372) culture line. Findings: The porous material may be used for the non-biodegradable scaffold. After implantation into the body in the form of an implant-scaffold one, it allows the natural cells of the patient to grow into the pores of the implant, and it fuses with the bone or the appropriate tissue over time. The essential part of the implant-scaffold is the porous part inseparably connected with the core of solid materials. Into pores can grow living cells. Research limitations/implications: Biological-engineering composite materials in which natural cells were cultured in the pores in the laboratory next are combined as an artificial material with the natural cells of the patient in his/her body. Practical implications: The hybrid technologies of the all group of those materials were obtained and optimised. Numerous structure research was carried out using the most modern research methods of contemporary materials engineering, and mechanical tests and biological research involving the cultivation of natural cells were realised. Originality/value: The results of the research indicate the accuracy of the idea of implementing a new group of biological-engineering materials and the wide possibilities of their application in regenerative medicine.

Opto-mechanical oscillator in a nanoliter droplet

Droplets are very simple physical systems, whereby surface tension shapes liquids into ideal opto-mechanical devices. This has recently enabled low-viscosity liquid samples to serve as miniature acoustic resonators harnessing optical generation of bulk vibrations, capillaries, or surface waves. Uniquely, a simple room-temperature pendant droplet can be activated as a hypersound-laser emitter when illuminated by a free-space, low-power visible laser thanks to stimulated Brillouin scattering of optical and acoustic whispering-gallery modes. Here, we demonstrate continuous operation of a liquid polymer opto-mechanical resonator and characterize its quality factor and long-term frequency stability. Our results point to the feasibility of all-liquid micro-mechanical oscillators working in the 50-100 MHz range. The stimulated generation of high-quality surface waves on nanoliter droplets gives momentum to new optical schemes for characterization of material viscous-elastic properties, laboratory investigation of atmospheric phenomena, and mass sensing for direct analysis of biological fluids based on ultrasound-hypersound coherent generation and detection.

Selected toxic and essential heavy metals in impacted teeth and the surrounding mandibular bones of people exposed to heavy metals in the environment

BACKGROUND

The elemental composition of bones and teeth can allow exposure to heavy metals in the environment to be estimated. The aim of this study was to determine whether impacted mandibular teeth and the surrounding bones can be used as biomonitoring media to assess exposure to heavy metals.

METHODS

The research materials were 67 impacted lower third molars and samples of the cortical bone removed when the wisdom teeth were surgically extracted. The samples were from people living in two areas with different environmental concentrations of heavy metals. The cadmium, chromium, copper, iron, lead, manganese, and zinc concentrations in the samples were determined by atomic absorption spectrometry with flame atomization.

RESULTS

The cadmium and lead concentrations in the impacted third molars and the bones surrounding the teeth were significantly higher for people living in the relatively polluted Ruda Slaska region than for people living in Bielsko-Biala region. Significantly higher chromium, copper, manganese, and zinc concentrations were found in the bones surrounding the impacted teeth from people living in Ruda Slaska than in the bones surrounding the impacted teeth from people living in Bielsko-Biala. The cadmium concentrations in impacted teeth and the surrounding bones were significantly positively correlated.

CONCLUSION

The results indicated that impacted mandibular teeth and the surrounding mandibular bones may reflect the exposure of people to cadmium and lead in the environment. This conclusion, however, must be verified in future research projects designed to exclude the possibility of additional dietary, occupational, and other types of exposure to heavy metals.

Mode-splitting cloning in birefringent fiber Bragg grating ring resonators

In this Letter, we report the theoretical model and the experimental evidence of a mode-splitting cloning effect due to the resonant coupling between modes having different polarizations in weakly birefringent fiber Bragg grating (FBG) ring resonators. This modal coupling depends on the fiber birefringence and the FBG reflectivity. In the ideal case of the absence of birefringence, a single split-mode resonant structure can be observed in the resonator transmission spectrum due to the degeneracy removal of the two counter-propagating modes. In the presence of FBG birefringence, a secondary split doublet resulting in a clone of the initial one is generated. The described effect can be exploited for spectroscopic-sensing applications based on more complex split-mode dynamics.

Fiber Bragg grating laser sensor with direct radio-frequency readout

A fiber Bragg grating (FBG)-coupled ring laser sensor is demonstrated. In the proposed configuration the interrogating source, the sensing head and the readout instrument are integrated in a single fiber-optic device. An FBG inserted within a bidirectional fiber ring couples the two counterpropagating modes of the cavity, generating a splitting of the resonant wavelengths proportional to the FBG reflectivity. When the cavity gain is brought beyond threshold, the two peaks of the split resonances simultaneously lase, leading to a beat note in the emission spectrum whose frequency tracks any small shift of the FBG reflectivity spectrum. Such a beat note can be simply monitored by a frequency counter, without the need for an optical spectrometer, allowing to significantly reduce size and costs of the sensor setup. The sensing performance compares well to the state-of-the-art thermo-mechanical fiber sensors.

Laser-frequency locking to a whispering-gallery-mode cavity by spatial interference of scattered light

We present a simple and effective method for frequency locking a laser source to a free-space-coupled whispering-gallery-mode cavity. The scheme relies on the interference of spatial modes contained in the light scattered by the cavity, where low- and high-order modes are simultaneously excited. A dispersion-shaped signal proportional to the imaginary component of the resonant optical field is simply generated by spatial filtering of the scattered light. Locking of a diode laser to the equatorial modes of a liquid droplet resonator is demonstrated using this scheme, and its performance is compared to the Pound-Drever-Hall technique. This new approach makes laser-frequency locking straightforward and shows a number of advantages, including robustness, low cost, and no need for sophisticated optical and electronic components.

Influence of aging solutions on wear resistance and hardness of selected resin-based dental composites

PURPOSE

The purpose of this study was to investigate the effect of different plasticizing aging solutions on wear resistance and hardness of selected universal resin-based dental composites.

METHODS

Three light cured (one nanofilled, two microhybride) and one hybride chemical cured composites were aged at 37 °C for 48 h in distillated water, ethyl alcohol solution or Listerine mouthwash. After aging the microhardness tests were carried out and then tribological tests were performed in the presence of aging solution at 37 °C. During wear testing coefficients of friction were determined. The maximal vertical loss in micrometers was determined with profilometer.

RESULTS

Aging in all liquids resulted in a significant decrease in hardness of the test materials, with the largest values obtained successively in ethanol solution, mouthwash and water. The effect of the liquid was dependent on the particular material, but not the type of material (interpreted as the size of filler used). Introduction of mouthwash instead of water or ethanol solution resulted in a significant reduction in the coefficient of friction. The lowest wear resistance was registered after aging in ethanol and for the chemical cured hybrid composite, but the vertical loss was strongly material dependent.

CONCLUSIONS

The effect of different aging solution, including commercial mouthrinse, on hardness and wear was material dependent, and cannot be deduced from their category or filler loading. There is no simple correlation between hardness of resin-based dental composites and their wear resistance, but softening of particular composites materials during aging leads to the reduction of its wear resistance.

Enhanced spectral response of π-phase shifted fiber Bragg gratings in closed-loop configuration

The transmission spectrum of a ring resonator enclosing a π-phase shifted fiber Bragg grating (π-FBG) shows a spectral feature at the Bragg wavelength that is much sharper than resonance of the π-FBG alone, and that can be detected with a simple integrated cavity output technique. Hence, the resolution of any sensor based on the fitting of the π-FBG spectral profile can be largely improved by the proposed configuration at no additional fabrication costs and without altering the sensor robustness. A theoretical model shows that the resolution enhancement attainable in the proposed closed-loop geometry depends on the quality factor of the ring resonator. With a commercial grating in a medium-finesse ring, a spectral feature 12 times sharper than the π-FBG resonance is experimentally demonstrated. A larger enhancement is expected in a low-loss, polarization maintaining setup.

Split-mode fiber Bragg grating sensor for high-resolution static strain measurements

We demonstrate a strain sensor with very high sensitivity in the static and low frequency regime based on a fiber ring cavity that includes a π phase-shifted fiber Bragg grating. The grating acts as a partial reflector that couples the two counter-propagating cavity modes, generating a splitting of the resonant frequencies. The presence of a sharp transition within the π phase-shifted fiber Bragg grating's spectral transmittance makes this frequency splitting extremely sensitive to length, temperature, and the refractive index of the fiber in the region where the grating is written. The splitting variations caused by small mechanical deformations of the grating are tracked in real time by interrogating a cavity resonance with a locked-carrier scanning-sideband technique. The measurable strain range and bandwidth are characterized, and a resolution of 320  pϵ/Hz(1/2) at 0 Hz is experimentally demonstrated, the highest achieved to date with a fiber Bragg grating sensor.

The study of barium concentration in deciduous teeth, impacted teeth, and facial bones of Polish residents

The study determines the concentration of Ba in mineralized tissues of deciduous teeth, permanent impacted teeth, and facial bones. The study covers the population of children and adults (aged 6-78) living in an industrial area of Poland. Teeth were analyzed in whole, with no division into dentine and enamel. Facial bones and teeth were subjected to the following preparation: washing, drying, grinding in a porcelain mortar, sample weighing (about 0.2 g), and microwave mineralization with spectrally pure nitric acid. The aim of the study was to determinate the concentration of Ba in deciduous teeth, impacted permanent teeth, and facial bones. The concentration of barium in samples was determined over the ICP OES method. The Ba concentration in the tested bone tissues amounted to 2.2-15.5 μg/g (6.6 μg/g ± 3.9). The highest concentration of Ba was present in deciduous teeth (10.5 μg/g), followed by facial bones (5.2 μg/g), and impacted teeth (4.3 μg/g) (ANOVA Kruskal-Wallis rank test, p = 0.0002). In bone tissue and impacted teeth, Ba concentration increased with age. In deciduous teeth, the level of Ba decreased with children's age.

High-sensitivity ring-down evanescent-wave sensing in fiber resonators

We report on optical-fiber cavity ring-down spectroscopy (CRDS) in the liquid phase using a laser emitting at telecommunication wavelengths. A fiber-ring cavity, comprising a short evanescent-wave coupler for radiation-matter interaction, is used as a sensor while its resonance modes are frequency locked to the laser. Exploiting the intrinsic sensitivity and noise immunity of the CRDS technique, we show that liquid absorption can be detected down to a level that is nearly a factor of 20 above the shot noise limit. We provide a thorough comparison between the experimental results and various noise contributions and address different expressions that can be used to calculate the shot noise equivalent absorbance. As a proof of principle, polyamine detection in aqueous solutions is carried out demonstrating a minimum detectable absorbance of 1.8×10(-7)  Hz(-1/2), which, to our knowledge, is the best sensitivity limit reported to date for evanescent-wave sensors.

Localized strain sensing with fiber Bragg-grating ring cavities

We report the theoretical description and the experimental demonstration of an optical resonator formed by inserting a Fiber Bragg Grating (FBG) in a closed fiber loop. The spectral characteristics of such a resonator strongly depend on the reflectivity of the FBG. In the wavelength region where the FBG reflectivity R is negligible, the system behaves like a conventional ring resonator. On the other hand, when R is not vanishing, a split-mode structure can be observed, associated to the degeneracy removal of two counterpropagating resonant modes. The magnitude of the mode splitting can be used to sense small variations of the FBG physical parameters, such as length, temperature or group index. An example of strain sensing with this setup is reported, showing that the mode splitting is sensitive to a mechanical strain applied to the FBG, while it is almost insensitive to a strain applied to any other point of the resonator. This peculiar feature allows to perform cavity-enhanced, local strain measurements with a reduced sensitivity to environmental perturbations, which represents an important improvement in the framework of the fiber-optic sensors.

Two-tone frequency-modulation spectroscopy in off-axis cavity

As opposed to a conventional optical resonator, an off-axis-aligned cavity is able to transmit without distortion radiation modulated at a frequency even far above the cavity bandpass. This allows us to implement a simple spectroscopic technique that combines the cavity path-length enhancement of integrated cavity output spectroscopy (ICOS) and the noise reduction associated with radio-frequency modulation (FM). An FM-ICOS spectrometer is demonstrated for the first time using a two-tone modulation technique. The performance is compared to the traditional ICOS by examining the acetylene absorption at 1543.77 nm. A signal-to-noise ratio improvement by a factor 3.5 is found with our proof-of-concept setup. Larger improvements are expected in a more optimized setup.

Surface plasmon resonance optical cavity enhanced refractive index sensing

We report on a method for surface plasmon resonance (SPR) refractive index sensing based on direct time-domain measurements. An optical resonator is built around an SPR sensor, and its photon lifetime is measured as a function of loss induced by refractive index variations. The method does not rely on any spectroscopic analysis or direct intensity measurement. Time-domain measurements are practically immune to light intensity fluctuations and thus lead to high resolution. A proof of concept experiment is carried out in which a sensor response to liquid samples of different refractive indices is measured. A refractive index resolution of the current system, extrapolated from the reproducibility of cavity-decay time determinations over 133 s, is found to be about 10(-5) RIU. The possibility of long-term averaging suggests that measurements with a resolution better than 10(-7) RIU/√Hz are within reach.

Absolute frequency measurement of molecular transitions by a direct link to a comb generated around 3-microm

A 3-microm continuous-wave difference-frequency source is directly referenced to a mid-infrared optical frequency comb synthesizer by measuring their beat-note signal by a fast HgCdTe detector. Absolute frequency metrology of molecular vibration spectra is demonstrated by locking the 3-microm coherent radiation to the nearest comb tooth and tuning the comb mode spacing across the Doppler-broadened absorption profile of a CH(4) ro-vibrational transition.

Non-collinear quasi phase matching and annular profiles in difference frequency generation with focused Gaussian beams

We present and experimentally test a simple model for difference frequency generation (DFG) in periodically-poled crystals with gaussian pumping beams. Focusing of input beams originates several non-collinear quasi-phase-matching configurations of the interacting wavevectors, which contribute to the idler output field. In this picture, we accurately describe a number of effects, such as the occurrence of annular idler intensity profiles and the asymmetric trend of DFG power vs temperature. Finally, we quantitatively test the model by means of an indirect measurement of the crystal poling period.

Do the levels of selected metals differ significantly between the roots of carious and non-carious teeth?

Since the metals deposited in teeth during formation and mineralization processes are to a large extent retained, human teeth receive a considerable attention as the indicators of the heavy metal exposure. The use of permanent teeth is limited because the extraction of healthy permanent teeth just for this purpose is hardly acceptable. As the issue of the loss of elements from a carious lesion in the coronal part of a tooth remains controversial, the valuable material could only be the root of carious and fractured permanent teeth. However, to ensure the validity of the results, it should be ascertained that the levels of certain toxic and essential elements do not differ significantly between the roots of non-carious and carious teeth, and therefore this is the aim of this project. The levels of cadmium, chromium, copper, iron, manganese, lead, zinc, potassium, sodium, calcium and magnesium were determined in the roots of 344 permanent teeth (189 carious and 155 caries-free teeth) from the residents of Ruda Slaska, Poland, aged 18 to 34. No statistically significant difference between the concentration of these metals in the roots of non-carious and carious teeth was found. This finding applies to both the general population and after the grouping by donor's gender and tooth type. The concentration of lead, iron, calcium and manganese in the roots of non-carious and carious teeth exhibited dependence upon tooth type, as well as the concentration of potassium in the roots of carious teeth. Since the mineral composition of the roots of permanent teeth is similar for the non-carious, as well as the carious teeth, they can be indiscriminately selected for the tests required by a research project, as they will produce the comparable results. However, in the case of lead, iron, calcium, potassium and manganese, the comparison should be made after grouping by tooth type.

Characteristics of maxillofacial injuries resulting from road traffic accidents--a 5 year review of the case records from Department of Maxillofacial Surgery in Katowice, Poland

Background

In spite of employing numerous devices improving the safety in motor vehicles, traffic accidents are still among the main reasons of maxillofacial injuries. The maxillofacial injuries remain the serious clinical problem because of the specificity of this anatomical region. The knowledge of etiologic factors and mechanisms of injuries can be helpful in a satisfactory trauma prevention. The aim of this study was to find out the incidence and the pattern of maxillofacial injuries resulting from traffic accidents in the patients treated in the Department of Maxillofacial Surgery (Silesian Medical Academy in Katowice, Poland) from January 2001 to December 2005.

Methods

The material consisted of 1024 case records of patients with maxillofacial injuries treated in the Maxillofacial Surgery Department of Silesian Medical Academy. The detailed analysis was carried out on the case records of 198 patients in the age of 3 to 68 with maxillofacial injuries resulting from traffic accidents. On the basis of data from a history, examination on admission, consultations and radiological examinations, patients' age and gender, we obtained the information on a pattern of injury and detailed description of an accident (the date and the time of an accident, the role of the patient in an accident).

Results

The traffic accidents were the cause of 19,93% maxillofacial injuries in the analyzed period of time. Most of the patients had injuries to the soft tissues of the face (22,21%), followed by tooth and alveolar process injuries (20,71%) and mandibular fractures (18,69%). All the types of injuries were more common in men than in women. The majority of the patients were car drivers followed by car passengers, pedestrians, cyclists and motor cyclists. The peak age of the patients was between 18 to 25 years. The prevalent number of accidents resulting in injuries to this region took place in spring, especially between noon and 4 PM.

Conclusion

Our results exhibit that road traffic accidents remain among the main reasons of maxillofacial injuries following the traumas resulting from assaults and interpersonal violence. This succession of etiologic factors is in accordance with the data from the most developed countries. The relatively high incidence of injuries resulting from traffic accidents indicates the necessity to reinforce legislation aimed to prevent road traffic crashes and thus to reduce maxillofacial injuries among children and adults.

[Malignant lymphoma or inflammation? Diagnostic and treatment difficulties--2 cases report]

Soft and hard tissue in the oral cavity can be the first coexisting place of systemic diseases manifestation. The aim of this study was to report the diagnostic and treatment difficulties in two patients with malignant lymphomas. The first case was a 66-year-old woman who had undergone surgery procedures connected with radiotherapy and chemotherapy because of malignant lymphoma in nasal cavity in 2001 year. In 2002 she was treated in our department after finding tumor in oral cavity, also diagnosed as malignant lymphoma. The second patient was a 58-year-old man who had undergone an operation (surgery) by reason of maxillary inflammation tumor in 2002 year. On the next year he underwent an operation of removal cervical lymp nodes because of malignant lymphoma. In 2004 year he underwent surgery on account of maxillary tumor suspected by malignant lymphoma, which was diagnosed as inflammation. Conclusions. In differentiation tumors of head and neck one should take an account of lymphoma malignant. The similar clinic and radiological symptoms and laboratory results of malignant lymphomas and inflammations of head and neck can cause the late diagnosis and aggravate the prognosis of this severe disease.

Combining a difference-frequency source with an off-axis high-finesse cavity for trace-gas monitoring around 3 microm

High-sensitivity spectroscopy of methane around 3 microm was carried out by means of a 5.5-mW cw difference-frequency generator in conjunction with a high finesse cavity in off-axis alignment. By cavity-output integration a minimum detectable absorption coefficient of 5.7*10-9 cm-1Hz-1/2 was achieved, which compares well with results already reported in the literature. Detection of methane in natural abundance was also performed in ambient air, for different values of total pressure, allowing direct concentration measurements via evaluation of the integrated absorbance of the spectra. In particular, at atmospheric pressure, a minimum detectable concentration of 850 parts per trillion by volume (pptv)*Hz-1/2 was demonstrated.

[Effect of passive smoking on the level of selected metals in deciduous teeth]

The cigarette smoke is a significant source of heavy metals, which after being absorbed into the human organism, may be accumulated in a calcified tissue. The accumulation process may be also a result of a passive exposure to the cigarette smoke. As the hard tissues of deciduous teeth are relatively stable in chemical composition, they are widely used as the indicators of the exposure to heavy metals in children. This project is aimed to estimate the effect of passive smoke on the levels of selected toxic and essential elements in deciduous teeth. The research material consisted of 386 deciduous teeth. Out of this, 205 teeth were from the children exposed to the cigarette smoke in the apartments. The levels of cadmium, copper, iron, manganese, lead, zinc, calcium and magnesium were determined using atomic absorption spectrometer with flame atomization. It was concluded that the exposure to the cigarette smoke in children is a factor producing the changes in the levels of selected toxic and essential elements in deciduous teeth. This particularly results in the higher levels of cadmium, copper, lead and zinc, which are the permanent constituents of the cigarette smoke, and the lower levels of manganese, calcium and magnesium. Moreover, the disturbed gradient of lead levels dependent on the tooth type is observed in the children exposed to the cigarette smoke in the apartments.

[Smoking and drug use among students of selected univerities]

Smoking, drinking alcohol and drugs are still actual social and health problems in Poland and in the world as well. Conducted studies, considering health behaviours among children and youth, indicate high percentage (between 20-30%) of smokers in mentioned population, depending on age, gender and environment. Health effects caused by smoking occur usually in adulthood as smoking related diseases, despite the addiction leading to the health problem begins earlier, even in childhood. Statistics, considering drinking alcohol and drugs abuse among young people are also frightening. The aim of the study was to evaluate and compare the state of knowledge about harmful effects of smoking, drinking alcohol and drugs use among students of Silesian Medical University, Silesian University of Technology and Academy of Physical Education and to evaluate and compare health attitudes towards mentioned addictions among students of different Universities. 315 students at age between 19-24 years took part in the study and filled in the anonymous questionnaire prepared by authors. Surveyed population included 108 students of Silesian Medical University, 110 students of Silesian University of Technology and 97 students of Academy of Physical Education in Katowice. Knowledge, presented by all students, about harmful effects of smoking, drinking alcohol and drugs use is not put into practice and does not result in healthy behaviours in examined part of life style. Students of Silesian Medical University demonstrate the highest state of knowledge about drugs. Students of Academy of Physical Education in Katowice have the most improper behaviours in the area of addictions. There is a necessity of preparing and spreading efficacious prophylactic programmes in order to raise awareness about the harmfulness of smoking, drinking and drugs use.

Dynamics of changes in vascular endothelial growth factor (VEGF) expression and angiogenesis in stress-induced gastric ulceration in rats

Angiogenesis and VEGF play a major role in many repair processes such as healing of gastric ulceration. The present study was undertaken to assess the dynamics of changes in VEGF expression and angiogenesis in stress-induced gastric ulcers in rats. Acute gastric ulceration was induced using a water-immersion and restraint stress method. The VEGF expression, angiogenesis, size of area and depth of ulcers in gastric specimens were evaluated. The study shows that as early as one day after the development of ulcers there is a significant increase in both the expression of the VEGF protein and the number of newly formed microvessels, while an abrupt decrease in VEGF expression, observed on the fifth day, results in a decreased intensity of angiogenesis. Moreover, it has been demonstrated that the increase in VEGF expression and angiogenesis is accompanied by a reduction in the size of area and depth of stress-induced ulcers in rats. Six days after ulcer development both VEGF expression and angiogenesis return to normal levels.

[The effect of tobacco smoking on occurrence of precancerous lesions and cancers of oral cavity--literature reviews and own experiences]

Tobacco smoking results in many serious health problems. It exhibits also significant influence on oral health and is linked with occurrence of oral precancers and cancers. In this paper, on the basis of literature review and own experiences, we tried to prove the close relationship between tobacco smoking and occurrence of oral precancers, their malignant transformations and therapeutic effects. We pointed out on significantly higher cancer occurrence in this region among smokers. We emphasized the role of physicians, whose professional interest was focused on oral health, in prophylaxis of oral cancers and advising patients smoking cessation.

[Evaluation of knowledge and health attitude towards cigarette smoking, alcohol and drugs use among students]

Cigarette smoking, drinking alcohol and drug use are important epidemiological problems affecting state of health. Negative effects of these unhealthy behaviors are commonly known and result in many socioeconomic consequences. Despite relatively good knowledge about harm-fullness of cigarette smoking a percentage of smokers in polish population is still high, especially in young population, and hesitates between 20-30% depending on age, sex and socioeconomic conditions. Negative health attitude towards smoking, drinking alcohol and drug use among young people requires further education and promotion in this area. Aim of the study was evaluation of knowledge about harmful effects of smoking, drinking alcohol and drug use among students of Silesian University of Technology and evaluation of health attitudes towards smoking, drinking alcohol and drug abuse in examined population. 109 students of Silesian University of Technology at age between 19-24 years took part in the study and filled the anonymous questionnaire prepared by authors. The study revealed that 8% of Silesian University of Technology students smoke cigarettes regularly. 15% of students declare smoking occasionally despite most of them know negative effects of such smoking. Almost 80% do not smoke at all. In opinion of 66,7% passive model of smoking is as harmful as the active one. Relatively many (8%) of examined students admit drinking alcohol regularly. Only 15% do not drink alcohol. 35% of students declare taking a drug, at least once during entire life, and some of examined consider marihuana as not addictive. High knowledge about harmful effects of smoking among students results in a relatively low percentage of inveterate smokers. Despite knowledge about harmfulness of drinking alcohol and drug abuse proper healthy behaviors in this area are not put into practice in examined motion in order to reduce unhealthy behaviors among young people.

[Influence of smoking tobacco on the condition of dentition and occurence of periodontal diseases in patients of the Clinic of Maxillo-Facial Surgery at the Silesian Medical Academy in Katowice]

Popularity of smoking cigarettes in the Polish society is a widely known and discussed subject. Negative effects of smoking cigarettes as well as passive expose to the tobacco smoke are often described. Still, only a few publications focus on the frequency of a smoking habit among patients of clinics and facial and maxillary surgery wards as well as its influence on condition of their oral cavities. It is obvious that these people should particularly avoid smoking cigarettes due to the deterioration of the oral cavity hygiene, substantial differences in healing wounds and induction of neo-plastic changes. The goal of the survey was examining the frequency of the smoking habit among patients of the Departmental Outpatient Clinic of Maxillo-Facial Surgery at the Silesian Medical Academy in Katowice, the assessment of influence of the smoking habit on the oral cavity condition and hygiene. The survey covered 50 patients have been selected at random and they are all treated in the Departmental Outpatient Clinic of Maxillo-Facial Surgery at the Silesian Medical Academy in Katowice. The patients' age was from 21 to 64. In the group being surveyed, 17 patients (34% of the whole) admitted to the smoking habit. 7 patients, the so-called "heavy smokers", admitted to smoking more than 5 cigarettes a day (this group equalled 14% of the whole). Ten patients (20% of the whole) were moderate smokers who smoked fewer than 5 cigarettes a day. In spite of efforts of managing physicians, advertisements supporting a healthy lifestyle, and discouraging information on packets of cigarettes, fighting the habit is very difficult and it does not always lead to giving up smoking.

[Effect of cigarette smoking on coexistence of cadmium and zinc in retained wisdom teeth]

The change in coexistence pattern of elements (antagonism-synergism) in conditions of excessive level of toxic element is observed in many biological samples. The aim of this study was to establish the cadmium and zinc content in hard tissues of retained wisdom teeth of smokers and non-smokers and to find out if active exposure to cigarette smoke has an influence on coexistence of both metals in these tissues. Material consisted of 127 retained wisdom teeth (65 from smokers and 62 from non-smokers). Cadmium and zinc contents were determined by means of atomic absorption spectrometry. We found out that retained wisdom tooth from smokers exhibited higher cadmium and zinc contents compared to non-smokers' teeth. Moreover, coexistence pattern of cadmium and zinc in teeth depends on exposure to heavy metals and exhibits strong synergism in smokers.

[Lead and cadmium occurrence in deciduous teeth of children exposed to cigarette smoke in apartments]

The aim of this study was to find out if children's exposure to tobacco smoke in the apartments influences the lead and cadmium content and the values of Pb/Ca and Cd/Ca ratios in hard tissues of their deciduous teeth. Material consisted of 71 shed deciduous teeth; 37 from children in the age of 6 to 13 years additionally exposed to tobacco smoke in the apartments and 34 from children in the same age, whose apartments were free of tobacco smoke. Lead, cadmium and calcium content was determined by means of flame atomic absorption spectrometry. Deciduous teeth of children additionally exposed to tobacco smoke in the apartments exhibited higher lead and cadmium content and higher values of Pb/Ca and Cd/Ca ratios, which indicated significant accumulation of these metals, when compared to deciduous teeth of children whose apartments were free of tobacco smoke.

[Cigarette smoking practices in patients with malignant neoplasms of the oral cavity and jaws]

The aim of this study was to estimate the cigarette smoking practices in patients with malignant neoplasms of the oral cavity and jaws, who were treated in the Outpatient Department of the Maxillofacial Department of Silesian Medical Academy in Katowice from january 2000 to june 2004. It was found that significant number of patients (100% of men and 72.72% of women) with oral squamous cell carcinoma had been smoking in the period of time preceding appearance of neoplasm. The men smoked more cigarettes a day and started smoking in a younger age than women. Gender factor did not influence significantly the period of time from starting of smoking practices to the appearance of neoplasm. The patients with the other types of neoplasms denied cigarette smoking.