Composition and Nano-Periodic Structure of Compounds Formed by the Reaction of Molybdenum and Tungsten Heteropolyanions with Cationic Surfactants

Keggin heteropolyanions (HPAns) of structure [PMo 12 O 40 ] 3– and [PW 12 O 40 ] 3– have been allowed to react in acidic media at room temperature with some cationic surfactants of the quaternary ammonium or primary amine type to yield meso-structured insoluble salts with the general formulae Am 3 [PM 12 O 40 ], Etn 3 [PM 12 O 40 ] 2 , Etn 3 [PM 12 O 40 ] 2 •nEtnCl 2 or Am n H 7-n [PM 11 O 39 ]•xH 2 O, where Am and Etn are, respectively, mono- and di-cationic surfactant species, M is Mo or W and n can vary in the range 0 to ∼3. All of the materials obtained possessed nano-periodic structures whose maximum d 100 parameters ranged from 26 Å to 36 Å, exhibiting lamellar, tetragonal, hexagonal or cubic meso structures depending on the synthesis conditions employed and the nature of the surfactant and HPAns used. The values of the highest d 100 parameter obtained for the substances prepared were generally in line with the length of the hydrophobic tail in the surfactant molecule but less dependent on the nature of the metal (Mo or W) when the latter was incorporated in a Keggin anion. However, the structure of the materials was considerably influenced by the pH value of the reaction medium and the P/M ratio when transformation of the Keggin anions into lacunary or other anions was possible

Synthesis and Characterization of Ti—MCM-41-Type Mesoporous Molecular Sieves with High Titanium Contents

By employing a sodium silicate + titanium tetrabutoxide + trimethylmyristylammonium bromide system, it has been possible to obtain mesoporous titanosilicate Ti–MCM-41-type molecular sieves containing systematically varying titanium contents. The samples obtained possessed a high BET specific surface area and exhibited the perfect hexagonal mesoporous structure characteristic for MCM-41 materials even when the titanium fraction present was as great as 20 mol%. It has been shown that most of the titanium can be expelled from the structure when the materials are treated with sulphuric acid solution. However, such treatment does not destroy their inherent hexagonal structure, thereby suggesting that the titanium is preferentially localized in the mesopore surface layer. The structure/sorption properties of the materials were investigated by X-ray diffraction methods and by the adsorption of n-hexane and water vapour. A possible mechanism for the formation of such MCM-41-type molecular sieves is proposed which suggests that the use of organometallic ethers M(OR) n , accompanied by ether solubilization with organic micellar templates, leads to the preferential localization of M in the mesopore surface

Nanometals in energetic systems: Achievements and future

The characterization of nanometals that are mostly produced by electrical explosion of wires and a comprehensive survey of their usage in different energetic systems are presented. The greatest attention is devoted to nanoaluminum, which is the most common representative of nanometals. The improved kinetic characteristics of chemically reacting systems typical for nanometals (such as burning and detonation rate enhancement for propellants, explosives, and thermites) are studied, and novel paths for chemical reactions are opened (such as nitrides formation in oxygenated media and the catalytic effect on the decomposition of energetic materials). A poor correlation between the powder properties and the slow oxidation parameters was found as a result of very wide scatter in the nanometals characteristics. The burning rate enhancement factor (K) was analyzed for nanoaluminum-loaded solid propellants. The most promising energetic systems are nanometal-loaded solid fuels that are HTPB and ice based with chemically inert matrices

Injury to the posterior cruciate ligament: biomechanics, diagnosis, treatment and prevention of secondary osteoarthritis

The literature was reviewed for reports on the pathogenesis, diagnosis and treatment of injuries to the posterior cruciate ligament (PCL). PCL is the largest intra-articular ligament in the knee joint and has good tensile mechanical properties. Optimal diagnosis and appropriate treatment strategies for PCL injury are discussed. Nonoperative treatment of isolated PCL injuries is associated with a significant risk of degeneration of the knee structures and impaired function. A comprehensive line of PCL reconstruction options are offered for the surgical approach to PCL reconstruction to restore functional joint stability in the knee. Literature data on protective effect of glucosamine, chondroitin sulfate in the prevention of secondary knee osteoarthritis caused by PCL ruptures were reviewed. © 2020 © Korolev A.V., Afanasyev A.P., Il'in D.O., Gerasimov D.O., Ryazantsev M.S., Kadantsev P.M., 202

Adsorptive Properties of Template-Containing Silica-Based MCM-41 and MCM-50 Materials

Template-containing silica-based MCM-41 and MCM-50 materials have been shown to have microporous adsorbent properties, with the characteristic adsorption energy in such micropores being strongly dependent on the molecular mass of the adsorptives employed. The total adsorption volume was found to decrease as the molar volume of the adsorptive increased. A model explaining the peculiarities of the adsorptive properties of the template-containing materials is proposed

Stabilization of acromioclavicular joint using DogBone dynamic system (Arthrex): A literature review and long-term follow-up

Objectives The purpose of the study was to evaluate long-term follow-ups of stabilized acromioclavicular joint (ACJ) dislocations using button dynamic system applied via arthroscopic technique or mini-open. Material and methods The review included follow-ups of 40 patients (39 males, 1 female) who underwent 40 ACJ stabilization procedures with Arthrex DogBone button between 2014 and 2017 using arthroscopy (n = 28) or mini-open technique (n = 12). The mean age of the patients was 34 years (range, 15 to 59 years). Patient reported outcomes were evaluated with UCLA shoulder rating scale, American Shoulder and Elbow Surgeons (ASES) shoulder score and the Constant Shoulder Score (CSS). Coraco- Clavicular Distance (CCD) was measured on pre- and postoperative anteroposterior views. Postoperative AP view was used to measure Clavicular Tunnel Distance (CTD). Arthroscopy patients had available preoperative radiographs (n = 21), postoperative radiographs (n = 26) and patient reported outcomes (n = 18). Mini open group had available preoperative radiographs (n = 2), postoperative radiographs (n=8) and patient reported outcomes (n = 8). Results One hundred percent of Arthroscopy/Mini open (26/26) cases were rated as excellent and good on UCLA shoulder rating scale at a long-term follow-up. One hundred percent of Arthroscopy patients (18/18) were rated as excellent and good; 75 % (6/8) of Mini-open cases evaluated as excellent and 25 % (2/8) as good on ASES shoulder score. Sixty seven percent of Arthroscopy (12/18) patients were rated as excellent and 33 % (6/18) as good; 62 % (5/8) of Mini open cases evaluated as excellent and 38 % (3/8) as good. Neither fair nor poor results were observed in both groups. No statistically significant differences were detected in median scores between Arthroscopy and Miniopen groups (p > 0.05). Preoperative radiographs showed Tossy grade IV dislocation (n = 3) and Tossy grade III (n = 20). Distal clavicle fracture was diagnosed in 2 cases. Median preoperative CCD radiologically measured 15.5 mm in both groups (n = 23). Median postoperative CCD and CTD radiologically measured 6.12 mm and 28.9 mm in both groups (n = 35), correspondingly. Decrease in postoperative CCD was significantly different (p = 0.0003). No statistically significant differences in postoperative CCD were detected between Arthroscopy and Miniopen groups (p > 0.05). Statistically significant differences in preoperative CCD were observed in both groups (n = 15) using weight-bearing/no weight-bearing AP views (P = 0.0009). Conclusion Stabilization of dislocated ACJ with dynamic systems is the method of choice providing excellent and good outcomes rated by UCLA rating scale, ASES shoulder score and CSS at long-term follow-up. One-stage surgical treatment is an advantage of dynamic systems with no need of construct removal. Standard and weighted stress radiographs of the involved side indicate to ACJ injury in comparison with contralateral side. Further research is needed for a longer term follow-up with the bone reduction maintained with dynamic system. © Ryazantsev M.S., Il'in D.O., Rybin K.E., Magnitskaya N.E., A.P. Afanasyev, Logvinov A.N., Korolev A.V., 2018

Infection after Arthroscopic Cuff Tear Repair (Case Report)

Septic shoulder arthritis following arthroscopic surgery is a rare complication, according to the literature it arises from 0.006% to 2,1% of cases. We report on a case of 58 y.o. patient, admitted to our setting 10 days after arthroscopic intervention on the right shoulder joint in another hospital. Based on clinical, laboratory and instrumental assessment septic shoulder arthritis was diagnosed. Arthroscopic lavage and debridement surgery with bioabsorbable antibacterial agent implantation was performed. Long term follow-up in 6 months showed good results with full range of motion, absence of pain and elimination of infection

Damage of the knee posterior cruciate ligament: biomechanics, basic diagnostics, treatment and secondary osteoarthritis prevention directions [Povrezhdeniya zadnei krestoobraznoi svyazki: biomekhanika, osnovnye napravleniya diagnostiki, lecheniya i profilaktiki vtorichnogo osteoartrita]

The analysis of literature data was performed on the pathogenesis, diagnosis and treatment of injuries of the posterior cruciate ligament (PCL) of the knee joint. PCL is the largest intra-articular ligament of the knee joint, can withstand the maximum loads compared with other ligaments. It was noted that, in general, in cases of damage to the PCL, it is necessary to use a set of diagnostic methods, and the basic principles for the choice of optimal treatment plan for this patient. It considered the results of the conservative treatment of PCL partial ruptures, and it is indicated that this approach increases the risk of degenerative anatomical structures and functional disorders of the joint. It was noted that it is advisable to conduct surgical treatment to restore the stability of the knee joint and normalize function, while a number of methods for the reconstruction of PCL have been proposed to date. The usage of chondroprotectors for prevention of the secondary osteoarthrosis of the knee joint affected by posterior cruciate ligament rupture was analyzed in the literature data.Проведен анализ литературных данных об особенностях патогенеза, диагностики и лечения повреждений задней крестообразной связки коленного сустава (ЗКС). ЗКС является самой большой внутрисуставной связкой коленного сустава, выдерживающей максимальную нагрузку по сравнению с другими связками. Отмечено, что в целом при повреждениях ЗКС необходимо использование комплекса методов диагностики. Проанализированы основные принципы выбора тактики лечения данной категории пациентов. Рассмотрены результаты консервативного лечения частичных разрывов ЗКС, при этом указано, что такой подход увеличивает риск дегенерации анатомических структур и функциональных нарушений сустава. Целесообразно выполнение хирургического лечения для восстановления стабильности коленного сустава и нормализации его функции, при этом к настоящему времени предложен ряд методов реконструкции ЗКС. Проанализированы литературные данные о применении препаратов группы хондропротекторов для профилактики вторичных остеоартрозных изменений коленного сустава на фоне разрыва задней крестообразной связки

ТРАНСПАТЕЛЛЯРНАЯ РЕКОНСТРУКЦИЯ МЕДИАЛЬНОЙ ПАТЕЛЛОФЕМОРАЛЬНОЙ СВЯЗКИ АУТОТРАНСПЛАНТАТОМ ИЗ СУХОЖИЛИЯ ПОЛУСУХОЖИЛЬНОЙ МЫШЦЫ

Purpose of the study - to evaluate surgical treatment outcomes of the patients with chronical patella instability who underwent double bundle transpatellar reconstruction of medial patella-femoral ligament (MPFL) by a semitendinous tendon autograft. Material and methods. 26 patients with minimal 12 months follow up were included into the study. In all cases semitendinous tendon autograft was inserted through a vertical tunnel in the patella, formed in a loop, and fixed in femoral tunnel by a biodegradable screw. Preoperative MRIs were used to evaluate trochlear dysplasia type by D. Dejour classification, tibial tubercle to trochlear groove distance (TT-TG) and Insall-Salvati ratio. Postoperative x-rays were used to measure femoral tunnel angle (FTA), postoperative MRIs - to measure diameter of patella tunnel (d_Pat), distance from tunnel to medial border of patella (MPM) and diameter of tunnel in medial femoral condyle (d_Fem). Functional outcomes were evaluated by Kujala Score, Lysholm and IKDC, also the authors assessed the level of sports activity prior to and after the surgery. Results. Age median of the patients at the moment of procedure was 22 years. MRI data prior to surgery reported that the majority of patients suffered from B type of trochlear dysplasia, median TT-TG distance was 14.6 mm, median Insall-Salvati ratio was 1.1 mm. Postoperative x-rays and MRIs demonstrated median FTA of 18 degrees, d_Pat median 5.4 mm, MPM median - 7.0 mm, d_Fem median - 8.2 mm, no implant migrations were observed. Subjective assessment scores demonstrated excellent outcomes: Kujala Score - 96, IKDC - 87.4, Lysholm - 91. No secondary dislocations during follow up were reported, 48% of patients returned to sports on the pre-surgery or higher level, 52% of patients returned to sports with decreased activity. Conclusion. Transpatellar reconstruction of MPFL by semitendinous tendon autograft proved to be the efficient treatment method of chronical patella instability.Цель исследования — оценить результаты хирургического лечения пациентов с хронической нестабильностью надколенника, которым была выполнена двухпучковая транспателлярная реконструкция медиальной пателлофеморальной связки (MPFL) аутотрансплантатом из сухожилия полусухожильной мышцы. Материал и методы. В исследование были включены 26 пациентов с минимальным сроком послеоперационного наблюдения 12 мес. Во всех случаях аутотрансплантат из сухожилия полусухожильной мышцы проводили через вертикальный канал в надколеннике, формируя «петлю», и фиксировали в канале бедренной кости при помощи биодеградируемого винта. На предоперационных МРТ оценивали тип дисплазии блока бедренной кости по классификации D. Dejour, расстояние между бугристостью большеберцовой кости и блоком бедренной кости (TT-TG) и индекс Insall — Salvati. На послеоперационных рентгенограммах измеряли угол наклона бедренного канала (FTA), на послеоперационных МРТ измеряли диаметр канала в надколеннике (d_Pat), расстояние от канала до медиального края надколенника (MPM) и диаметр канала в медиальном мыщелке бедренной кости (d_Fem). Функциональные результаты оценивали с использованием опросников Kujala Score, IKDC и Lysholm, определяли уровень спортивной активности до и после операции. Результаты. Медиана возраста пациентов на момент хирургического лечения составила 22 года. По данным МРТ, перед операцией у большинства пациентов был зафиксирован тип В дисплазии блока бедренной кости, медиана расстояния TT-TG составила 14,6 мм, медиана индекса Insall — Salvati — 1,1 мм. По данным послеоперационных рентгенограмм и МРТ, медиана FTA составила 18°, медиана d_Pat — 5,4 мм, медиана MPM — 7,0 мм, медиана d_Fem — 8,2 мм, миграции имплантатов не наблюдалось. Субъективные опросники показали отличные результаты: Kujala Score — 96 баллов, IKDC — 87,4 балла, Lysholm — 91 балл. Повторных вывихов за период наблюдения не отмечалось, 48% пациентов вернулись к спорту на прежних и более высоких уровнях, 52% вернулись к спорту, однако снизили уровень активности. Заключение. Транспателлярная реконструкция MPFL аутотрансплантатом из сухожилия полусухожильной мышцы является эффективным методом лечения хронической нестабильности надколенника