Relevance. The administration of antibiotics in implantology is indicated to prevent suppurative inflammation conditions. Two regimens are commonly used: a single preoperative dose or prolonged postoperative antibiotic administration. Due to ethical constraints, certain parameters of antibiotic efficacy cannot be directly evaluated within clinical trials. These include the status of the implant-mandibular segment microbiome and the histological parameters of the tissue's inflammatory response at the implant site.Materials and methods. This study employed a miniature pig model comprising 10 males. The cohort was equally divided into two groups of five animals each. Group 1 received a single preoperative dose of amoxicillin/clavulanic acid 2 ml per 20 kg body weight. Group 2 received the same initial dose prior to implantation, followed by a daily postoperative dose of amoxicillin/clavulanic acid at 1 ml per 20 kg body weight for five days. Each animal received six dental implants. An implant site microbiological test was performed pre-surgery, on Day 1, 3, 7 and 14 post-surgery. Core needle biopsies for histological examination of the tissues were performed on the same postoperative days.Results. Microbiological testing revealed that Group 2 exhibited lower levels of Streptococcus spp. on Day 3 (p = 0.04) and Porphyromonas spp. on Day 7 (p = 0.04). Group 1 demonstrated reduced levels of Fusobacterium spp. on Day 1 (p = 0.02) and Porphyromonas spp. both pre-surgery (p = 0.04) and on Day 1 (p = 0.012). Comparative analysis of histological assays from the implant sites indicated identical tissue inflammatory responses, regardless of the antibiotic prophylaxis regimen.Conclusion. Both the single-dose and the prolonged antibiotic prophylaxis regimens, using amoxicillin/clavulanic acid for dental implantation, demonstrated similar histological patterns of tissue inflammation at the implant site, along with comparable microbiota profiles within the implant site. The oral mucosa exhibited an increased population of Staphylococcus spp. and Streptococcus spp., which might contribute to the development of resistant strains, as well as Candida spp., potentially increasing the risk of candidiasis infection onset.

The stockwork gold-sulphide-quartz ores of the Pavlik deposit (North-East of Russia) are formed mainly by homogeneous, low saline (9.4—4.3 wt. % eq. NaCl), essentially water-chloride fluid at temperatures of 275о–330оC and a fluid pressure of 600—1840 bar. The fluid is characterized by a sufficiently high CO2 and a reduced methane content – the ratio of CO2 / CH4 = 17—37.3. In the fluid, among the cations, the main role is played by: Na and Ca, and K and Mg are in a subordinate amount. In addition, many trace elements were detected in the fluid composition: As, Li, Rb, Cs, Mo, Ag, Sb, Cu, Zn, Cd, Pb, U, Ga, Ge, Ti, Mn, Fe, Co, Ni, V, Cr, Y, Zr, Sn, Ba, W, Au, Hg and REE. The obtained data allow us to assume a decrease in the depth of ore formation during the formation of the deposit by 4—5 km due to the rise of the ore-bearing block. Attention is drawn to the low fluid pressures for a number of samples (330—140 bar), which may be associated with a separate stage of mineral formation. The ore-forming fluid of the Pavlik deposit in composition, temperatures and pressures shows similarities with the fluids of the neighboring Natalka and Rodionovsky deposits and has a great similarity with typical fluids of orogenic gold deposits. The information given in the article is of great practical importance for regional predictive metallogenic constructions, prospecting and evaluation of gold deposits.

Millions of people worldwide suffer from musculoskeletal damage, thus using the largest proportion of rehabilitation services. The limited self-regenerative capacity of bone and cartilage tissues necessitates the development of functional biomaterials. Magnetoactive materials are a promising solution due to clinical safety and deep tissue penetration of magnetic fields (MFs) without attenuation and tissue heating. Herein, electrospun microfibrous scaffolds were developed based on piezoelectric poly(3-hydroxybutyrate) (PHB) and composite magnetic nanofillers [magnetite with graphene oxide (GO) or reduced GO]. The scaffolds' morphology, structure, mechanical properties, surface potential, and piezoelectric response were systematically investigated. Furthermore, a complex mechanism of enzymatic biodegradation of these scaffolds is proposed that involves (i) a release of polymer crystallites, (ii) crystallization of the amorphous phase, and (iii) dissolution of the amorphous phase. Incorporation of Fe3O4, Fe3O4-GO, or Fe3O4-rGO accelerated the biodegradation of PHB scaffolds owing to pores on the surface of composite fibers and the enlarged content of polymer amorphous phase in the composite scaffolds. Six-month biodegradation caused a reduction in surface potential (1.5-fold) and in a vertical piezoresponse (3.5-fold) of the Fe3O4-GO scaffold because of a decrease in the PHB β-phase content. In vitro assays in the absence of an MF showed a significantly more pronounced mesenchymal stem cell proliferation on composite magnetic scaffolds compared to the neat scaffold, whereas in an MF (68 mT, 0.67 Hz), cell proliferation was not statistically significantly different when all the studied scaffolds were compared. The PHB/Fe3O4-GO scaffold was implanted into femur bone defects in rats, resulting in successful bone repair after nonperiodic magnetic stimulation (200 mT, 0.04 Hz) owing to a synergetic influence of increased surface roughness, the presence of hydrophilic groups near the surface, and magnetoelectric and magnetomechanical effects of the material.

THE AIM OF THE STUDY:Was to determine the presence of an amoxicillin-based antibiotic in bone implant biopsies by Raman spectroscopy in an experiment.MATERIALS AND METHODS:Experimental animals (n=10, a miniature pig of the Svetlogorsk breed) were divided into 2 groups of 5 animals. Groups 1 and 2 were injected with amoxicillin 2 ml per 20 kg of body weight 30 minutes before dental implantation surgery, then group 2 was additionally injected with 1 ml per 20 kg of body weight for 5 days. Each animal has 6 implants installed. On the 1st, 3rd, 7th, 14th day, an implant-bone biopsy was removed from each animal, micro-preparations were made and Raman spectroscopy was performed to assess the peak matching of the Raman spectrum.RESULTS:In animals of the 1st and 2nd groups, the main peak of the Raman spectrum, which is closest to the values of the antibiotic spectrum of interest to us, is located closer to 1448 cm-1 and 1446 cm-1, respectively. At the same time, in both observations, the peaks relate to the spectrum of bone tissue, which cannot indicate the content of an antibiotic in the drug.CONCLUSION:No scattering spectra corresponding to the antibiotic molecule were found in any animal from both groups, regardless of the mode of administration and dosage of amoxicillin. The detected peaks corresponded to bone tissue without an antibiotic.

For the first time, the results of modern studies of the earth's crust based on gravity data from the GOCE satellite Project are used for a comparative regional metallogenic analysis of the geodynamic settings of the formation of polymetallic deposits in Western Europe and the Mediterranean segment of the Tethys belt. It is shown that exhalative sulfide deposits (SEDEX) and cuprous sandstones and shales (SSC) are mainly located in the earth's crust with a predominant development of the lower “basalt” layer of the earth's crust. Pyrite copper and lead-zinc deposits in volcanogenic rocks (VMS), as well as some occurrences of the SEDEX type, are found in supra-subduction island-arc and accretionary crustal settings with a predominant development of the middle “granite” layer. Lead-zinc ores of the Mississippi type (MVT) are localized in deep pericratonic sedimentary basins with petroleum-bearing specialization on the shelf and continental slope, regardless of the stratification of the earth's crust. The results obtained can be used for regional forecasting and metallogenic constructions, prospecting and assessment of new deposits.

For the first time by the method of scanning electron microscopy, REE mineralization studies are conducted in alkaline rhyolites of the Pechalninskii ore field (Northeast Russia), a potentially large-volume source of HREEs. It is shown using the methods of electron microprobe analysis and cathodoluminescence that microcrystalline aggregates of pyroxenes and/or amphiboles in alkaline rhyolites contain the finest inclusions of REE segregations (5–7 µm). Using SEM, it is determined that the largest segregation is cerium phosphate. Concentrically zonal and radial-fibrous REE segregations are revealed in the relics of titanomagnetite crystals by EDS. The first ones are represented by silicates enriched with Y and REEs and the content of each REE varies regularly from the center to the edge. The radial-fibrous aggregates are represented by oxides and/or carbonates containing REEs (La, Ce, and Nd predominate). The results obtained can be used in the development of enrichment technology.

Placer deposits had (and for a number of components still have) an important role in providing strategic types of mineral resource base for both Russia and the world as a whole. Placers have a number of advantages that make them in demand by the mining industry: relatively shallow (often accessible for open-pit mining) occurrence, disintegrated state of productive deposits, simplicity of enrichment processes (mainly gravitational systems), as well as the possibility of rapid involvement in exploitation, which significantly reduces payback period for investments. All this is even more relevant for modern Russia, when, in the shortest possible time, in conditions of a shortage of credit resources, it is necessary to implement a program of import substitution and provide the country with scarce types of strategic mineral raw materials, such as gold, platinum group metals, tin, rare metals, titanium, chromium, diamonds.

Based on the research carried out on the territory of the Arctic zone of Russia the authors have identified ore districts that are promising for the discovery and development of Pb-Zn deposits, among which only one large Pavlovskoe deposit (Novaya Zemlya Archipelago) is at the development stage. More than 20 facilities are dispersed in the Murmansk and Arkhangelsk regions, the Yamalo-Nenets Autonomous Area, Taimyr, the Republic of Sakha (Yakutia) and the Chukotka Autonomous Area. They outline that most of the ore districts are located in the 100-km zone of economic accessibility (high priority of mineral resources development) to the Northern Sea Route. Within the three-ore districts, it is possible to form new mining clusters, including several nearby deposits. The authors indicate prospects for the discovery of new deposits as well as challenges in the development of the mineral resource base of the considered ore regions: lack of infrastructure, arctic climate, remoteness, and the need for a large volume of geological exploration.

The Republic of Guinea has outstanding mineral resources. An analysis of current data has shown that in the near future this country will maintain its leading position in the world in the extraction and export of bauxite, as well as increase the production and export of alumina. Guinea has significant potential to develop large and rich iron ore deposits, but the development of this industry is hampered by the lack of infrastructure and an unstable geopolitical situation. Gold mining is successfully developing in the Siguiri ore region, where new promising deposits are discovered almost every year and new mines are put into operation. Guinea’s diamond deposits are among the most famous in West Africa and the world as a whole. However, the fall in global diamond prices in recent years has led to a slowdown in exploration, a lack of major discoveries and, consequently, a reduction in exports.

This paper considers geological, mineralogical, and geochemical features of the epithermal Au‒Ag mineralization at the Televeem volcanic dome uplift (VDU) which complicates the Verkhne-Pykarvaam volcano-tectonic depression (VTD) in the Central Chukchi sector of the Okhotsk–Chukchi volcanogenic belt (OCVB). The structure of this ore occurrence is due to its localization within the eponymous VDU. The main vein zone (MVZ) of the Televeem ore occurrence, as wide as 500 m, extends for 2.5 km in the north–south direction. Along the MVZ direction, en-echelon proximal quartz–adularia veins are successively replaced with zones of thin streaks and brecciation in secondary quartzites and argillisites. The gold concentrations in these rocks vary between 1.4 and 17.3 g/t, that of gold is between 7.6 and 144.6 g/t. The ores contain abundant brecciated, framboidal lamellar, geode, and fine streaky structures. The more frequent ore minerals are pyrite, arsenopyrite, acanthite, grey ores of the freibergite–tetrahedrite series, stephanite, polybasite, low-fineness native gold (fineness varies in the range 249–532‰), and titanite. The amount of ore minerals in veins does not commonly exceed 0.5

Copper mineralization in the Magadan region (North-East of Russia) has been established in quartz-chloritoid and chlorite shales of the middle and upper Riphean of the Prikolymsky terrane. Compared to the upper crust, copper shales of the Oroek deposit are noticeably enriched in a narrow range of trace elements: Cu, Ag, Au, Rh, and Se, with enrichment factors ranging from 10-fold (Se, Rh) to 100-fold (Ag, Au) and even 1000-fold (Cu) suggesting, apparently, their synchronous involvement in ore formation. In addition, the studied samples are slightly enriched in Cd, Li, Co, Zn, V, U, Sc, Y, and REE. Copper shales show relatively flat rare earth element (REE) patterns similar to the chondrite-normalized pattern having no distinct positive or negative Eu anomalies and dominated by light lanthanides. The Ce/Ce* and Eu/Eu* values indicate that ore formation proceeded under oxidizing conditions. The obtained geochemical data show that the Riphean host rocks could serve as a source of trace elements and REE ore-forming fluids. In the ores, covellin and chalcocite are the main copper minerals; less common are roxbyite, idaite, nukundamite, spioncopite, chalcopyrite, silver-bearing (Ag about 1 wt. %) bornite and yarrovite, as well as native gold. Fluid inclusions in quartz suggest that copper mineralization was formed at temperatures of 212–190 °C and a pressure of 1 kbar, from hydrothermal solutions of medium salinity (from 13.8 to 12.4 wt. % eq. NaCl) and high density (0.95–0.98 g/cm3) saturated with chlorides of Ca, Mg, and K. The copper shales of the Prikolymsky terrane differ from sedimentary copper and copper shales of the African Belt by low Co and Ni contents and from the Kupfershifer by low concentrations of Pb and Zn. The obtained results can be used for prognosticating new deposits.

Trachyriolites and komendites of the Pechalninsky ore field contain high potentially industrial concentrations of a number of rare metals and REE. The enrichment coefficients vary from several times (Zn, Ga, LREE) to tens (Be, Y, Zr, Nb, Rb and heavy HREE). The REE distribution indicates a uniform enrichment of the HREE relative to the LREE, with a ratio (La/Yb)N in the range from 0.16–1.01). All samples show strongly negative Eu anomalies, with values of Eu/Eu* – 0.13. A comparative analysis with similar objects known in the world in alkaline volcanites has shown that the Pechalninsky ore field can become an unconventional large-volume source of HREE.

The role of metallic nano- and microparticles in the development of inflammation has not yet been investigated. Soft tissue biopsy specimens of the bone bed taken during surgical revisions, as well as supernatants obtained from the surface of the orthopedic structures and dental implants (control), were examined. Investigations were performed using X-ray microtomography, X-ray fluorescence analysis, and scanning electron microscopy. Histological studies of the bone bed tissues were performed. Nanoscale and microscale metallic particles were identified as participants in the inflammatory process in tissues. Supernatants containing nanoscale particles were obtained from the surfaces of 20 units of new dental implants. Early and late apoptosis and necrosis of immunocompetent cells after co-culture and induction by lipopolysaccharide and human venous blood serum were studied in an experiment with staging on the THP-1 (human monocytic) cell line using visualizing cytometry. As a result, it was found that nano- and microparticles emitted from the surface of the oxide layer of medical devices impregnated soft tissue biopsy specimens. By using different methods to analyze the cell–molecule interactions of nano- and microparticles both from a clinical perspective and an experimental research perspective, the possibility of forming a chronic immunopathological endogenous inflammatory process with an autoimmune component in the tissues was revealed.

An Erratum to this paper has been published: https://doi.org/10.1134/S1075701523340019

The article considers the geochemical features of unconventional mineralization in secondary quartzite’s of the Kyplatap ore occurrence, located on the southeastern flank of the volcanic dome structure (VDS) of the same name, complicating the Palyavaam-Pykarvaam volcanotectonic depression (VTD) in the Chaun zone of the Central Chukotka sector of the Okhotsk-Chukotka volcanic Belt (OChVB). The Kyplatap VDS was formed due to the intrusion into the Late Cretaceous Alkaquun volcanites of a large laccolith-like subvolcanic body composed of rhyolite-trachyriolite-trachydacites. Based on the geochemical studies of the Kyplatap ore occurrence, the authors compiled a representative database of geochemical data, including the results of analyses of express-RFA, PKSA and XSA with coordinates and composition of ores and rocks. Correlation analysis of the database showed a positive relationship between Au and Ag, as well as Sb for ore mineralization, and a negative correlation of these elements with the association of the rock group of elements (Ti, Y, Zr, Nb and Yb) that were removed during ore formation. The authors also distinguished the second rock group of elements (K, Ga, Sn, Ba, V, W, Pb, Sc, La and B), characterized by medium and weak correlation of the first group of elements. They calculated the coefficients of enrichment and deficiency of ore-forming elements for the samples taken within the ore zones of the Kyplatap ore occurrence. The extreme enrichment group includes elements Au, Ag, Sb, Bi, As, the average contents of which are 100 times or more, and the minimum concentrations are at least 2-10 times higher than the average contents in the upper crust. The normal enrichment group includes elements S, Sn, Cu, Zn, Mn, Mo and Pb, the average contents of which are 2-10 times, and the maximum concentrations are 5-100 times higher than the average concentrations of the upper crust. The obtained values of the enrichment coefficients indicate a sufficiently intensive metensomatoses and ore formation within the Kyplatap ore occurrence.

Results of modern studies of the earth’s crust based on the gravitational data of the GOCE satellite have been used for the first time in a comparative metallogenic analysis of the geodynamic settings of the formation of polymetallic deposits in the folded frame of the Siberian and East European platforms. It is shown that deposits of the sedimentary exhalative deposits (SEDEX) type are more often located in the earth’s crust with the dominating development of the lower “basaltic” layer. Pyrite copper and lead–zinc volcanogenic massive sulfide (VMS) deposits, as well as some manifestations of the SEDEX type, occur in supra-subduction island-arc and accretionary settings in the crust with the dominating development of the middle “granitic” layer. Pb-Zn ores of the Mississippi Valley type (MVT) are localized in deep pericratonic sedimentary oil and gas basins on the shelf and continental slope, with no spatial relationship to the stratification of the earth’s crust. The Ag polymetallic mineralization of Taimyr and the Western Verkhoyansk region are confined to deep pericratonic rift troughs on the passive continental margin. They have a similar ore-bearing environment and can be combined into a single silver polymetallic Taimyr–Western Verkhoyansk belt. The results confirm the prospects of Pb-Zn deposits in Central and Eastern Taimyr and also in the Saurey ore region (Polar Urals), indicating the need for their further research.

This paper considers the conditions of formation for dominantly silver mineralization in the Kyplatap Volcanic Field (KVF), the Chaun Zone, the Central Chukchi Sector, and the Okhotsk-Chukchi Volcanogenic Belt (OChVB). New data are provided for the composition, distribution, and concentrations of trace elements, including REEs, in ore-bearing metasomatites. Appreciable enrichment of the samples in REEs, the dominance of light lanthanoids over heavy ones, very low Eu/Sm ratios ( ≪ 1 ), and low slopes of the near-chondrite spectra involving obvious europium minima, are all typical of the KVF epithermal mineralization system. The values of Ce/Ce* vary between small negative and moderate positive values (between 0.81 and 1.38), while Eu/Eu* varies between 0.28 and 0.7. This combination of Ce/Ce* and Eu/Eu* indicates oxidizing conditions that prevailed during mineralization. The results of thermometric and cryometric studies in fluid inclusions in quartz revealed the fact that the ore-forming fluid contained chlorides of Na, Mg, and K, the epithermal mineralization was deposited by homogeneous hydrothermal fluids with salt concentrations (0.3–6.2 wt

This article discusses the results of comprehensive studies of Sb-As ores of the Lojan deposit, located in the north-east of the Republic of North Macedonia (RSM), near the border with Serbia. 5 types of Sb-As ores have been identified: breccated realgar-auripigment ores, realgar breccias, breccated antimonite ores, massive, almost monomineral realgar ores, as well as realgar-antimonite nest-shaped ores. The ores are characterized not only by an unusual paragenesis of nickel, arsenic and antimony minerals, but also by a very close fusion of antimonite, realgar and collomorphic quartz. A wide range of elements in ores (As, Sb, Cr, Ti, Mn, Ni, Mo, Co, Ag, Tl, U, etc.) is apparently due to the combination of mineralization in ores of several different-time parageneses. As a result of thermometric studies of fluid inclusions in quartz, Thom vary from 180 OC to 220 OC (the average value is 201 OC). Studies of the isotopic composition of sulfur in antimonite and realgar have shown rather narrow ranges of δ34S values from -5.19 to -0.26 and from -4.80 to 1.92, respectively, which indicates an endogenous source of sulfur. The results obtained allow us to attribute the Lojan deposit to the epithermal class

The paper presents data on quartz-hosted fluid inclusions in commercial ores of various type (veinlet−disseminated and vein) of the Verninskoe gold deposit. The ores of various types were found out to significantly vary in the values of some of their physicochemical parameters of the fluids and in the composition of these fluids. The fluids that formed the gold veins have a somewhat higher initial temperature (356–246°C), a higher density of carbon dioxide in gas inclusions (1.00–0.84 g/cm3), and a higher fluid pressure (3170–1390 bar) than those of the fluids that formed the veinlet–disseminated ores (330–252°C, 0.87–0.54 g/cm3, and 1960–570 bar, respectively). The fluids that formed the gold veins were enriched in CО2, Sr, Ag, Ga, Ge, Mn, Fe, Ni, Sn, Ba, and REE, whereas the fluids that formed veinlet–disseminated mineralization were richer in HCO_3^ - , Br, Sb, V, and Au. This situations may be explained by the interaction of the deep fluid with the terrigenous host rocks in the course of ore deposition. When vein quartz crystallized in relatively wide fractures, the fluid interacted with host rocks and changed not as much as when the veinlet−disseminated ores were formed in narrow fractures. The initial parameters of the fluid that formed the vein quartz were thus the closest to the characteristics of the fluid that transported the ore components, and the comparison of these data with the parameters of the fluids that formed the veinlet–disseminated mineralization demonstrates that they changed in the course of ore deposition. The mineral-forming fluids likely came from a deep-sitting source, and the mineral-forming processes may have involve granitoid-derived fluids.

The Birkachan deposit in the Middle Paleozoic Kedonsky Volcanic Belt (KVB) is unique in Northeast Russia for its stockwork epithermal Au–Ag ores. The deposit is located in the northeastern part of the Gurnik volcanotectonic depression, in the Kedonsky segment of the KVB. The deposit is localized in the lying side of a large sublatitudinal thrust fault, due to which it was overlain in the Jurassic–Early Cretaceous by allochthon rocks and, therefore, was slightly eroded, as evidenced by the preserved fragments of the argillisite cap. The ore-bearing Gurnik sequence is composed of felsic tuffs and lavas with intercalations of ignimbrites. The main ore-bearing zone of the Birkachan deposit is 4.5 km long and 200–300 m wide consists of several echelon-like vein zones of northeast strike, falling to the southeast at angles of 55°–70°. Most of the ore bodies are linear stockworks. Single, lenticular rich ore bodies represented by mineralized breccias have been found at deep horizons. In the section, the system of ore bodies of the Birkachan deposit forms a fan-shaped structure. The main textures of ores are vein-disseminated, breccia, and rhythmically banded. The ores are enriched in comparison with the upper continental crust in a rather narrow range of elements (Au, Ag, Sb, As, Mo, W, and Li) and are poor in rare-earth elements, among which light lanthanides predominate. The sulfide grade of ores is 0.1–0.5%. The vein minerals in ores are dominated by quartz, sericite, and siderite. Among the ore minerals, pyrite dominates, with fahlore, native gold and chalcopyrite, and minerals of the series acanthite → Se–acantite → naumannite, pearceite, and Se–pearceite being less common. The average fineness value of native gold is 643‰. The parameters of mineral-forming solutions correspond to typical medium-temperature fluids of epithermal low-sulfidized deposits: homogenization temperature of 93–291°С, salt concentration of 0.2–7.0 wt % eq. NaCl, and fluid density of 0.71–0.99 g/cm 3 . The main indicators of fluid composition are CO 2 /CH 4 = 15.8–23.6, Na/K = 2.3–4.3, and K/Rb = 2007. The prospects for increasing the reserves of Au and Ag are associated with further study and exploration of the flanks and deep horizons of the deposit.