Rapid quasi-periodic oscillations in the relativistic jet of BL Lacertae.

Blazars are active galactic nuclei (AGN) with relativistic jets whose non-thermal radiation is extremely variable on various timescales1-3. This variability seems mostly random, although some quasi-periodic oscillations (QPOs), implying systematic processes, have been reported in blazars and other AGN. QPOs with timescales of days or hours are especially rare4 in AGN and their nature is highly debated, explained by emitting plasma moving helically inside the jet5, plasma instabilities6,7 or orbital motion in an accretion disc7,8. Here we report results of intense optical and γ-ray flux monitoring of BL Lacertae (BL Lac) during a dramatic outburst in 2020 (ref. 9). BL Lac, the prototype of a subclass of blazars10, is powered by a 1.7 × 108 MSun (ref. 11) black hole in an elliptical galaxy (distance = 313 megaparsecs (ref. 12)). Our observations show QPOs of optical flux and linear polarization, and γ-ray flux, with cycles as short as approximately 13 h during the highest state of the outburst. The QPO properties match the expectations of current-driven kink instabilities6 near a recollimation shock about 5 parsecs (pc) from the black hole in the wake of an apparent superluminal feature moving down the jet. Such a kink is apparent in a microwave Very Long Baseline Array (VLBA) image.

Blazar spectral variability as explained by a twisted inhomogeneous jet.

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.

[Modern trends in combined treatment of hemorrhoids: topical form Tribenoside + Lidocaine and phlebotonic Ginkgo biloba + Troxerutin + Heptaminol]. / Sovremennye trendy v kombinirovannom lechenii gemorroya: primenenie mestnoi formy tribenozid + lidokain i sistemnogo venotoniziruyushchego preparata ginkgo biloba + trokserutin + geptaminol.

Acute hemorrhoids are the most common reason for referring to coloproctologist in people of working age. In the modern world, food culture and lifestyle are the most prominent factors leading to the risk of hemorrhoids. In the 21st century, it is hard to overestimate an importance of potential employability and active social role regarding socio-economic well-being. This thesis applies to patients suffering from proctological diseases, and those with hemorrhoids prevail among these ones. Minimally invasive treatment and pharmacotherapy defined primary needs of patients, i.e. treatment should be quick, safe and effective. Favorable treatment outcomes are possible only in pathogenetic therapy. In this review, we will define the priorities in effective combined treatment of hemorrhoids.

[Common sense of diosmin administration in combined treatment of hemorrhoids]. / Zdravyi smysl primeneniia diosmina v kombinirovannom lechenii gemorroia.

Flavonoids are herbal medicines and widely used for chronic venous diseases and hemorrhoids. Flavonoid diosmin in both micronized and non-micronized form is a part of various drugs. According to literature data, flavonoids are able to reduce venous stasis, suppress local inflammation, improve venous tone and lymphatic outflow. It should be noted that biological models of in vivo trials have certain limitations while available data of different researches are contradictory. However, flavonoids were recommended for hemorrhoids in view of meta-analysis of 14 trials comparing flavonoids (diosmin, micronized purified flavonoid fraction and rutosides) with placebo in 1514 patients with hemorrhoids and Cochrane review of 24 randomized controlled trials (2,334 participants). These drugs should be administered as a part of complex therapy. At the same time, there is no conclusive evidence to prefer only one of these medicines. There are also no data confirming the benefits of daily dosage of 3000 mg per day of micronized fraction of flavonoids compared with 1800 mg of purified diosmin per day for treatment of acute hemorrhoids.

[Sphincter-sparing treatment of anal fissure]. / Sfinkterosokhraniaiushchaia taktika lecheniia patsientov s anal'noi treshchinoi.

Surgical treatment of the anal fissure is associated with unreasonably high risks of delayed development of fecal incontinence to gas or liquid stool. Standardized sphincter-preserving therapy, based on the pharmacological reduction of increased internal anal sphincter tone (chemical sphincterotomy) allows to improve significantly the results of the non-surgical approach of treating one of the most common pathology in proctological practice. Our work presents a retrospective analysis of the treatment of 295 patients with anal fissure treated with diltiazem ointment, nifedipine ointment, nitroglycerin ointment and botulinum toxin A. Significant improvement or disappearance of complaints was noted in 84% of patients. The use of botulinum toxin A was successfull in 10 out of 11 patients without the need of surgical intervention. High efficiency (91% of patients) of the sphincter-preserving approach with a significant decrease in the need for aggressive surgical manipulation allows to decrease sphincterotomy rate and reduces the risk of delayed fecal incontinence.

[Complications of the 'open' surgeries for severe acute pancreatitis]. / Oslozhneniia 'otkrytykh' operatsii pri tiazhelom ostrom pankreatite.

INTRODUCTION: With the unsuccessfulness of an intensive therapy and minimally invasive interventions in severe acute pancreatitis they resort to the 'open' surgical interventions. It is important to know about the classification of complications of such surgeries, the frequency of occurrences, the recognition peculiarities and the determination of a treatment plan for the practical surgery. AIM: The optimization of the usage of 'open' surgeries for patients with severe acute pancreatitis. MATERIAL AND METHODS: An 'open' surgery has been performed on 322 patients for 25 years, 102 (31.6%) of them had different complications, 35 (34%) of them died. The intraoperative, early and 'seamed' complications have been allocated. The rational treatment concepts of the complications of 'open' surgeries, which are special for their diversity and paired with tactical and technical difficulties, have been developed. CONCLUSION: The main reasons for the development of complications of 'open' surgeries for severe acute pancreatitis are the destruction of the wall of the main pancreatic duct, parapancreatitis, the intervention of a hollow organ or a vessel of trunk in a purulent lesion. As a rule, mentioned changes appear due to the long-team course of severe acute pancreatitis.