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We study the Callan–Gross ratio R=dσL/dσT in heavy-quark pair leptoproduction, lN→l′QQ¯X, as a probe of linearly polarized gluons inside unpolarized proton, where dσT (dσL) is the differential cross section of the γ⁎N→QQ¯X process initiated by a transverse (longitudinal) virtual photon. Note first that the maximal value for the quantity R allowed by the photon-gluon fusion with unpolarized gluons is large, about 2. We calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer–Mulders function, h1⊥g, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum value of the ratio R depends strongly on the gluon polarization; it varies from 0 to Q24m2 depending on h1⊥g. We conclude that the Callan–Gross ratio in heavy-quark pair leptoproduction is predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the longitudinal and transverse components of the charm and bottom production cross sections at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton. Keywords: QCD, Heavy-quark leptoproduction, Callan–Gross ratio, Proton spin

We study the azimuthal cos⁡φ and cos⁡2φ asymmetries in heavy-quark pair leptoproduction, lN→l′QQ¯X, as probes of linearly polarized gluons inside unpolarized proton, where the azimuth φ is the angle between the lepton scattering plane (l,l′) and the heavy quark production plane (N,Q). First, we determine the maximal values for the cos⁡φ and cos⁡2φ asymmetries allowed by the photon–gluon fusion with unpolarized gluons; these predictions are large, (3−1)/2 and 1/3, respectively. Then we calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer–Mulders function, h1⊥g, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum values of the azimuthal distributions depend strongly on the gluon polarization; they vary from 0 to 1 depending on h1⊥g. We conclude that the azimuthal cos⁡φ and cos⁡2φ asymmetries in heavy-quark pair leptoproduction are predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the azimuthal distributions in charm and bottom production at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton. Keywords: QCD, Heavy-quark leptoproduction, Azimuthal asymmetries, Proton spin

We present the QCD predictions for the azimuthal cos⁡2φ asymmetry in charm leptoproduction for the kinematics of the COMPASS experiment at CERN. The asymmetry is predicted to be large, about 15%. The radiative corrections to the QCD predictions for the cos⁡2φ distribution are estimated to be small, less than 10%. Our calculations show that the azimuthal asymmetry in charm production is well defined in pQCD: it is stable both perturbatively and parametrically, and practically insensitive to theoretical uncertainties in the input parameters. We analyze the nonperturbative contributions to the cos⁡2φ distribution due to the gluon transverse motion in the target and the c-quark fragmentation. Because of the c-quark low mass, the nonperturbative contributions are expected to be sizable, about (30–40)%. We conclude that extraction of the azimuthal asymmetries from available COMPASS data will provide valuable information about the transverse momentum dependent distribution of the gluon in the proton and the c-quark hadronization mechanism. Finally, we discuss the cos⁡2φ asymmetry as a probe of the gluonic analogue of the Boer–Mulders function, h1⊥g, describing the linear polarization of gluons inside unpolarized proton.

Background. Features of etiology, disadvantages of classical methods of therapy, as well as complications that arise, especially in the elderly, create the need to use new drugs and methods in the treatment of inflammatory periodontal diseases. They should have a detrimental effect on the microflora of dental plaque, help improve the hygienic condition of the oral cavity, cause a minimum number of side effects when taken for a long time, and help normalize microcirculatory processes. Recently, biologically active algae compounds have been increasingly introduced into therapy. Their chemical structure is different from modern antibiotics, so drugs based on microalgae, having the above qualities, can be an effective alternative in the treatment of bacterial infections. The purpose of the study is to identify the effectiveness of treating periodontitis in elderly patients using a chlorella suspension. Materials and methods. A study was conducted of the dynamics of the effectiveness of the effect of a chlorella suspension on the state of the microvasculature of periodontal tissues and the control of plaque formation in elderly patients. To evaluate clinical data, a hygiene index was determined for all patients - Green, Vermillion simplified index (OHIS) (1964). Laser Doppler flowmetry technology was used to diagnose the condition of the microcirculatory tissue system of the periodontium. Results. It was found that the studied indicators, which were determined before treatment, on the 14th day and 6 months after the end of therapy, demonstrated an improvement in the hygienic state of the oral cavity and a decrease in the inflammatory process in tissues due to the use of a chlorella suspension in the treatment of periodontitis in elderly patients. Conclusions. The use of chlorella in the treatment of periodontitis in elderly patients can significantly improve the condition of the periodontal microvasculature and the level of oral hygiene. These methods are non-invasive and have no contraindications for elderly patients.

The results of morphology and topography of the greater palatine foramen and the greater palatine canal, and their practical application in clinical practice are presented. A systematic literature search was performed using PubMed, eLibrary, and HAC databases. Effective anesthesia in dentistry can be achieved using local anesthesia methods. The success of anesthesia in the posterolateral parts of the upper jaw depends on an accurate knowledge of the anatomy of this area. The review of the anatomy and morphology of the greater palatine foramen and the greater palatine canal as the target point for conducting analgesia, the anatomical structure of the neurovascular bundle passing in the greater palatine canal, the thickness of the mucous membrane of the palate in its various sections. Techniques of regional anesthesia through the greater palatine canal are considered. It is noted that when carrying out this type of anesthesia, it is necessary to take into account the length, shape of the greater palatine canal, the angle of inclination of the needle to the injection point, (taking into account individual characteristics and under the control of conebeam computed tomography). As a result of the analysis, it was found that the choice of a certain type of surgical intervention depends on the clinical situation. However, to date, neither in domestic nor in foreign literature there is no single point of view about the anatomy and morphology of the greater palatine foramen and the greater palatine canal, which emphasizes the extreme urgency of further research of these anatomical formations.

The dimensional characteristics of the greater palatine foramen are of great importance in clinical practice during the blockade of the pterygoid ganglion through the greater palatine foramen, in addition, the greater palatine foramen is an important anatomical landmark for the collection of palatine donor tissue, reconstruction of the orofacial region of an oncological patient. Analgesia, taking into account the morphometry of the greater palatine foramen and the greater palatine canal, is the key to the maximum analgesic effect and the least likelihood of complications. That is why determining the location and dimensional characteristics of the greater palatine foramen with a preserved dentition and in the absence of teeth is relevant. The purpose of this study was to analyze the location of the greater palatine foramen in relation to other anatomical landmarks according to the literature. As a result of the analysis, it was found that most researchers recommend using large molars of the upper jaw as landmarks with a full dentition, and in the absence of teeth, the distance to the median seam of the palate, to the posterior border of the palate, to the posterior nasal spine can be used as landmarks.

Background. The purpose of the research is to study the anatomical features of the greater palatine foramen and the greater palatine canal in women of the first adulthood period. Materials and methods. The object of the study is 132 women of the first adulthood period (from 21 to 35 years). We studied the size characteristics of the greater palatine foramen and its shape; the size characteristics of the greater palatine canal and its shape. Results. It was found that the medio-distal diameter of the greater palatine foramen was 3.02 ± 0.63 mm on the right; 3.04 ± 0.64 mm on the left; the antero-posterior diameter was 4.99 ± 0.72 mm on the right, and 5.09 ± 0.74 mm on the left. The mediodistal diameter of the greater palatine foramen on the left is statistically significantly larger than on the right by 0.7 %; the antero-posterior diameter of the greater palatine foramen on the left is larger than on the right by 2 % (p < 0.01). 11 forms of the greater palatine foramen were identified: oval, elongated in the antero-posterior direction; oval, elongated in the medio-distal direction; rounded; semicircular; teardrop-shaped; ovoid; triangular; crescent-shaped; helical; diamond-shaped; bean-shaped. Mostly, the oval shape of the greater palatine foramen was revealed, elongated in the antero-posterior direction, less often-helical. The length of the greater palatine canal was 31.9 ± 2.7 mm on the right; 30.3 ± 2.9 mm on the left. It was found that the length of the greater palatine canal on the right is statistically significantly greater than on the left by 2.7 % (p < 0.01). Bilateral differences in the diameters of the greater palatine canal in the upper, middle, and lower third were statistically unreliable (p > 0.05). 6 forms of the greater palatine canal were identified: sickle-shaped; wave-shaped; hourglass shape; funnel shape with a bend in the lower third; channel straight and zigzag shape. Mostly, the sickle-shaped form of the greater palatine canal was detected, less often-the funnel-shaped channel with a bend in the lower third. Conclusions. The greater palatine canal and the greater palatine foramen have pronounced variability in size and shape. The greater palatine canal has pronounced bilateral differences in length; the greater palatine foramen has pronounced bilateral differences in medio-distal and antero-posterior diameters.

Background. The purpose of the research is to study the morphological features of the pterygopalatine canal and the pterygopalatine foramen in men of the mature age’s first period. Materials and methods. The object of the study was 129 men of the mature age’s first period (from 20 to 35 years). The parameters of the craniofacial complex, the size and shape of the greater palatine foramen and the greater palatine canal were studied. Results. It is established that the pterygopalatine foramen and the pterygopalatine canal have a pronounced variability in size and shape. Conclusion. The highest values of Medio-distal and anterior-posterior diameters of a pterygopalatine foramenand the length of the pterygopalatine canal l was statistically significantly higher in the group eurobotopen, the smallest in the group lipoprotei. Bilateral differences Mediodistal and anterior-posterior diameters of the pterygopalatine foramen and the length of the pterygopalatine canal in all groups as for the facial index Garson was statistically significant (p > 0,05). The most common form of a pterygopalatine foramen – oval, elongated in the front-rear direction (30–52 %), least often – helical (3–4 %), sickle (1–4 %). The most common form of the pterygopalatine canal is sickle – shaped (33–52 %), the most rare form is funnel – shaped with a bend in the lower third (3–7 %).