In Situ Observations of Interstellar Pickup Ions from 1 au to the Outer Heliosphere.

Interstellar pickup ions are an ubiquitous and thermodynamically important component of the solar wind plasma in the heliosphere. These PUIs are born from the ionization of the interstellar neutral gas, consisting of hydrogen, helium, and trace amounts of heavier elements, in the solar wind as the heliosphere moves through the local interstellar medium. As cold interstellar neutral atoms become ionized, they form an energetic ring beam distribution comoving with the solar wind. Subsequent scattering in pitch angle by intrinsic and self-generated turbulence and their advection with the radially expanding solar wind leads to the formation of a filled-shell PUI distribution, whose density and pressure relative to the thermal solar wind ions grows with distance from the Sun. This paper reviews the history of in situ measurements of interstellar PUIs in the heliosphere. Starting with the first detection in the 1980s, interstellar PUIs were identified by their highly nonthermal distribution with a cutoff at twice the solar wind speed. Measurements of the PUI distribution shell cutoff and the He focusing cone, a downwind region of increased density formed by the solar gravity, have helped characterize the properties of the interstellar gas from near-Earth vantage points. The preferential heating of interstellar PUIs compared to the core solar wind has become evident in the existence of suprathermal PUI tails, the nonadiabatic cooling index of the PUI distribution, and PUIs' mediation of interplanetary shocks. Unlike the Voyager and Pioneer spacecraft, New Horizon's Solar Wind Around Pluto (SWAP) instrument is taking the only direct measurements of interstellar PUIs in the outer heliosphere, currently out to ∼ 47 au from the Sun or halfway to the heliospheric termination shock.

Shocks in the Very Local Interstellar Medium.

Large-scale disturbances generated by the Sun's dynamics first propagate through the heliosphere, influence the heliosphere's outer boundaries, and then traverse and modify the very local interstellar medium (VLISM). The existence of shocks in the VLISM was initially suggested by Voyager observations of the 2-3 kHz radio emissions in the heliosphere. A couple of decades later, both Voyagers crossed the definitive edge of our heliosphere and became the first ever spacecraft to sample interstellar space. Since Voyager 1's entrance into the VLISM, it sampled electron plasma oscillation events that indirectly measure the medium's density, increasing as it moves further away from the heliopause. Some of the observed electron oscillation events in the VLISM were associated with the local heliospheric shock waves. The observed VLISM shocks were very different than heliospheric shocks. They were very weak and broad, and the usual dissipation via wave-particle interactions could not explain their structure. Estimates of the dissipation associated with the collisionality show that collisions can determine the VLISM shock structure. According to theory and models, the existence of a bow shock or wave in front of our heliosphere is still an open question as there are no direct observations yet. This paper reviews the outstanding observations recently made by the Voyager 1 and 2 spacecraft, and our current understanding of the properties of shocks/waves in the VLISM. We present some of the most exciting open questions related to the VLISM and shock waves that should be addressed in the future.

Alfvénic velocity spikes and rotational flows in the near-Sun solar wind.

The prediction of a supersonic solar wind1 was first confirmed by spacecraft near Earth2,3 and later by spacecraft at heliocentric distances as small as 62 solar radii4. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy5-7. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams8. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii9-11, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age12-14.

[ENDOCYTOSCOPY--NOVEL ENDOSCOPIC DIAGNOSTICS APPROACH: PRINCIPLES AND PROCEDURE].

Endocytoscopy is one of the most novel endoscopic diagnostic procedures, providing optical magnification up to 1150 times of gastrointestinal and respiratory tract mucosa. Such approach allows real-time tissue and cellular structure visualization. Endocytoscopy, along with confocal laser endomicroscopy, can be considered as "optical biopsy" in vivo. Of course, endocytoscopy currently is experimental diagnostic method, all available endocytoscopes are prototypes. According to published data, endocytoscopy can be used in precancerous conditions and early intramucosal cancer diagnostics in esophagus, stomach, colon and bronchial tree. Different types of endocytoscopes are used for examinations: some of them are baby-scopes, with fixed magnification 570-1150 times, introduced into accessory channel of the therapeutic parent-endoscope, others--are integrated type, providing scalable magnification from 80 to 380 times. As for traditional pathology ex vivo, for endocytoscopy mucosal cell nuclei stain is needed. For vital staining during endocytoscopy methylene blue, toluidine blue and crystal violet in different concentrations are more often used. In cases of squamous-cell dysplasia or cancer, it is recommended to use 1% methylene blue solution, whereas in intestinal type metaplasia, dysplastic changes and cancer (Barrett's esophagus, P. Correa precancerous cascade, colon adenomas), 1% toluidine blue is preferred. With endocytoscopy, after vital staining, we can visualize and estimate mucosa tissue and cell characteristics: papillae, crypt and gland shapes and sizes, their integrity (tissue markers); cell nuclei size and shape, polarity and nuclear dye intensity (cell markers).

[ENDOCYTOSCOPY--NEW TYPE OF ENDOSCOPIC EXAMINATION OF LOWER GASTROINTESTINAL AND RESPIRATORY TRACT].

Majority of published data describing endocytoscopic examination of upper gastrointestinal tract mucosa, but in recent publications, it is reported, that endocytoscopy is suitable for small bowel, colon, respiratory tract and even peritoneum "optical biopsy". In number of articles possibilities of celiac sprue diagnostics with endocytoscopy is discussed, but small-bowel endocytoscopy is limited, due to absence of endocytoscopes, compatible with enteroscopes. More widely endocytoscopy is used in colon, mostly in lateral-spreading adenomas diagnostics. Prof. S-E. Kudo developed endocytoscopic classification of colonic mucosa changes, used for differential diagnostics and lesion mapping, describing hyperplasia, adenomas with different grades of intraepithelial neoplasia, non-invasive and invasive cancer. Some authors reported about good possibilities of endocytoscopy in inflammatory bowel disease diagnostics. Most of data, related to respiratory tract endocytoscopic examination, focused on precancerous conditions and early pharyngeal and lung cancer, and the preliminary results are promising, but, unfortunately, for now, endocytoscopy in bronchial tree is limited, due to lack of thin endocytoscopes. According to some article data, it is possible to use endocytoscopy not only in gastrointestinal and respiratory tract, but also in optical confirmation of peritoneal tumor dissemination in gastric and ovarian cancer patients, and--in bladder mucosa examination.

[Endoscopic stenting of malignant stenosis in the cervical esophagus].

OBJECTIVE: to define the optimal approach for self-expanding metal stents (SEMS) installing in the cervical esophagus in cases of malignant stenosis and to select the optimal types of stents for this tumor location. MATERIALS: From 2004 to 2013 in P.A. Herzen Moscow Cancer Research Institute in 24 patients with cervical esophagus tumor stenosis endoscopic stenting was performed. 70% of installed stents were Choo Cervical (M.I. Tech, Korea), 13%--unspecialized Choo and Hanaro stents (M.I. Tech, Korea), and 17%--Gianturco-Z stents (Wilson-Cook, Ireland). Main contraindication for cervical esophagus stenting was location of the tumor margin less than 1 cm from the upper esophageal sphincter. In 21% of cases, endoscopic stenting was performed under combined fluoro- and endoscopic guidance, in 79%-- using only endoscopic approach. RESULTS: Technical success of stent placement was achieved in all patients; SEMS was installed at the previously defined level. The accuracy of stenting was not depended from the type of guidance procedure. The most intensive pain was observed in cases with "not specialized" stents with diameter of 18, 20 or 22 mm. Average pain level in such patients was 4.54 points (VAS). In the subgroup with "cervical" stents average pain intensity was not exceed 3 points. Chronic pain syndrome lasts lifelong in 17% of patients. CONCLUSION: The procedure of SEMS positioning under endoscopic guidance with individual selection of stent type allows restoring oral nutrition in patients with severe tumor stenosis of the cervical esophagus.

The heliosphere's interstellar interaction: no bow shock.

As the Sun moves through the local interstellar medium, its supersonic, ionized solar wind carves out a cavity called the heliosphere. Recent observations from the Interstellar Boundary Explorer (IBEX) spacecraft show that the relative motion of the Sun with respect to the interstellar medium is slower and in a somewhat different direction than previously thought. Here, we provide combined consensus values for this velocity vector and show that they have important implications for the global interstellar interaction. In particular, the velocity is almost certainly slower than the fast magnetosonic speed, with no bow shock forming ahead of the heliosphere, as was widely expected in the past.

Comparison of Interstellar Boundary Explorer observations with 3D global heliospheric models.

Simulations of energetic neutral atom (ENA) maps predict flux magnitudes that are, in some cases, similar to those observed by the Interstellar Boundary Explorer (IBEX) spacecraft, but they miss the ribbon. Our model of the heliosphere indicates that the local interstellar medium (LISM) magnetic field (B(LISM)) is transverse to the line of sight (LOS) along the ribbon, suggesting that the ribbon may carry its imprint. The force-per-unit area on the heliopause from field line draping and the LISM ram pressure is comparable with the ribbon pressure if the LOS approximately 30 to 60 astronomical units and B(LISM) approximately 2.5 microgauss. Although various models have advantages in accounting for some of the observations, no model can explain all the dominant features, which probably requires a substantial change in our understanding of the processes that shape our heliosphere.

Global observations of the interstellar interaction from the Interstellar Boundary Explorer (IBEX).

The Sun moves through the local interstellar medium, continuously emitting ionized, supersonic solar wind plasma and carving out a cavity in interstellar space called the heliosphere. The recently launched Interstellar Boundary Explorer (IBEX) spacecraft has completed its first all-sky maps of the interstellar interaction at the edge of the heliosphere by imaging energetic neutral atoms (ENAs) emanating from this region. We found a bright ribbon of ENA emission, unpredicted by prior models or theories, that may be ordered by the local interstellar magnetic field interacting with the heliosphere. This ribbon is superposed on globally distributed flux variations ordered by both the solar wind structure and the direction of motion through the interstellar medium. Our results indicate that the external galactic environment strongly imprints the heliosphere.