Hepatitis B and C virus infection among adult women in Jilin Province, China: an urban-rural comparison in prevalence of infection markers

Twin seroepidemiological surveys on prevalence of hepatitis B and C virus (HBV and HCV, respectively) infection were conducted on 100 adult women in total, 50 each in the provincial capital of Changchun and in a farming village in the vicinity in Jilin Province, northeast China. Positivity to three markers on HBV (ie HBsAg+, anti-HBs+, and anti-HBc+) was examined by RIA methods, and to one on HCV (anti-HCV+) by EIA. The results were evaluated in combination with two foregoing studies in Shandong and Shaanxi Provinces, and with special reference to possible urban-rural differences in prevalence. The prevalence of HBsAg+ cases was rather low (ie 9% when two groups were combined), but that of anti-HBs+ and anti-HBc+ cases was high, being 50% and 45%, respectively. Thus, the rate of HBV+ cases was 62%. The rate for HCV+ cases was 3%. The comparison of the prevalence between the city group and the village group showed that the rates for anti-HBs+ and HBV+ were significantly or marginally higher in the former group than in the latter, respectively. The HCV+ prevalence rate for the city group (4%) also tended to be higher than the corresponding rates for the village group (2%), although the difference was statistically insignificant. When evaluated together with the observation in Shandong and Shaanxi Provinces, it appears possible to generalize that the HBV infection prevalence is not higher and probably lower in rural areas than in urban areas, and that such may also be the case for the HCV infection prevalence.     

Moiréless correlations in ABCA graphene

Atomically thin van der Waals materials stacked with an interlayer twist have proven to be an excellent platform toward achieving gate-tunable correlated phenomena linked to the formation of flat electronic bands. In this work we demonstrate the formation of emergent correlated phases in multilayer rhombohedral graphene––a simple material that also exhibits a flat electronic band edge but without the need of having a moiré superlattice induced by twisted van der Waals layers. We show that two layers of bilayer graphene that are twisted by an arbitrary tiny angle host large (micrometer-scale) regions of uniform rhombohedral four-layer (ABCA) graphene that can be independently studied. Scanning tunneling spectroscopy reveals that ABCA graphene hosts an unprecedentedly sharp van Hove singularity of 3–5-meV half-width. We demonstrate that when this van Hove singularity straddles the Fermi level, a correlated many-body gap emerges with peak-to-peak value of 9.5 meV at charge neutrality. Mean-field theoretical calculations for model with short-ranged interactions indicate that two primary candidates for the appearance of this broken symmetry state are a charge-transfer excitonic insulator and a ferrimagnet. Finally, we show that ABCA graphene hosts surface topological helical edge states at natural interfaces with ABAB graphene which can be turned on and off with gate voltage, implying that small-angle twisted double-bilayer graphene is an ideal programmable topological quantum material.

Two-dimensional (2D) van der Waals heterostructures with an interlayer twist have provided a new avenue for observing emergent tunable many-body electron phenomena. Recent experimental realizations include twisted bilayer graphene (tBG) near the so-called “magic angle” of 1.1° (1–3), twisted double-bilayer graphene (tDBG) (4–6), ABC trilayer graphene on near-perfectly aligned hexagonal boron nitride (hBN) (ABC-tLG/hBN) (7, 8) and transition-metal dichalcogenide heterostructures (9–12) [with predictions on a variety of other systems (13, 14)]. All of these systems host an interplay of two phenomena––the presence of one or more van Hove singularities (which we colloquially refer to as “flat bands” henceforth) at low energy where the density of states is sharply peaked, and the existence of a moiré pattern that creates a unit cell that is about a hundred times larger than the carbon–carbon nearest-neighbor distance in graphene. The large number of electrons with quenched kinetic energy make the flat bands conducive to interaction-driven phases (15). The enlarged moiré unit cell is thought to reduce both the flat-band bandwidth and the interaction energy scales, and also introduces easily accessible integer fillings that create Mott-like insulating states (1–12), the relation of which to nearby superconductivity is debated. A natural question that arises from all of these works is whether the moiré pattern is a necessary condition for the observation of correlated many-body phases, or whether it is simply sufficient to further reduce the flat-band bandwidth and hence the kinetic energy in the heterostructure.In this regard, multilayer rhombohedral (ABC) graphene offers a different perspective toward achieving a flat-band edge without the use of a moiré potential (16). Indeed, in a seminal work (17), it was theoretically shown that the low-energy band structure of multilayer rhombohedral graphene has a sharply peaked density of state (DOS), with the band structure E(k)∝kN (where N is the number of layers) at low energy in the nearest-neighbor hopping approximation. This implies a peak in the DOS at charge neutrality in this material for N>2, with an appreciable fraction of the entire band within this peak (18). Indeed, this physics is already at play in ABC-tLG/hBN (7, 8), where some of the flatness of the bands comes from the intrinsic band structure of ABC graphene, which is then further flattened and isolated by the moiré pattern from the hBN alignment. A facile alternative to flatten the bandwidth without introducing a moiré potential is to simply increase the number of layers of the rhombohedral stacked graphene. Unfortunately, isolating rhombohedral stacked graphene of any thickness is extremely difficult as it is less energetically favorable than the multilayer counterpart, Bernal stacked graphene. Since the difference between rhombohedral and Bernal graphene is simply a lattice shift, and the interlayer van der Waals forces are weak, it is well known that rhombohedral graphene reverts to the Bernal form when samples are processed with heat, pressure, or while performing lithography (19). In this work, we show that twisting two sheets of tDBG by a tiny (<0.1°) angle is a simple and robust method to create large area (up to micrometer-scale) rhombohedral graphene of four-layer thickness (ABCA graphene). We present gate-tunable scanning tunneling microscopy and spectroscopy (STM/STS) measurements at 5.7 K on these regions. We show that correlated phases can be achieved without the need for a moiré pattern and that rhombohedral graphene has unique topological properties.     

Value of intraoperative transesophageal echocardiography in preventing serious complications during valvular surgery. A report of four cases

The value of routine transesophageal echocardiography (TEE) was confirmed by the detection of rare and potentially serious complications in four of 136 patients (2.9%) undergoing valvular surgery. In case 1, one leaflet of a St. Jude Medical (SJM) valve implanted in the mitral position was stuck in the closed position; normal valve function was restored by 90 degrees rotation of the prosthesis. In case 2, moderate regurgitation was observed after mitral valve replacement with a Carpentier-Edwards pericardial bioprosthesis. The mitral valve was replaced with a SJM valve; regurgitation was proved due to a suture loop jamming. In case 3, perivalvular leakage was detected after aortic valve replacement for infective endocarditis; an additional suture stopped the leakage. In case 4, a foreign body was observed in the left atrium after aortic valve replacement for calcified aortic stenosis. The left atrium was re-opened, and a free-floating portion of the calcified native aortic valve was identified and removed. Routine intraoperative TEE in valve surgery permits the identification and management of potentially serious complications before discontinuing cardiopulmonary bypass.     

The complete optical spectrum of liquid water measured by inelastic x-ray scattering

Interaction of light with matter is of paramount importance in nature. The most fundamental property of a material in relation to light is its oscillator strength distribution, i.e., how strongly it absorbs light as a function of wavelength. Once the oscillator strength distribution is determined precisely for a wide enough energy range, the optical constants such as absorbance and reflectance as well as a number of other properties of the material, some of which are seemingly unrelated to photoabsorption, can be deduced. Most important of all is the fact that the interaction of matter with fast charged particles can be described by its complete optical spectra [Inokuti, M. (1986) Photochem. Photobiol. 44, 279-285]. Despite their importance, however, the complete optical spectra of volatile liquids including water have never been obtained accurately because of experimental difficulties inherent in vacuum UV spectroscopy. Inelastic x-ray scattering spectroscopy can provide quantitative data equivalent to those from vacuum UV absorption spectra. Herein, we show the complete optical spectrum of liquid water determined by making use of intense monochromatic x-rays supplied by the wiggler line X21 of the National Synchrotron Light Source.     

Immunization of simian immunodeficiency virus-infected rhesus monkeys with soluble human CD4 elicits an antiviral response.

Since the CD4 molecule is a high-affinity cell-surface receptor for the human immunodeficiency virus (HIV), it has been suggested that a soluble truncated form of CD4 may compete with cell-surface CD4 for HIV binding and thus be of use in the therapy of AIDS. We have utilized the simian immunodeficiency virus of macaques (SIVmac)-infected rhesus monkeys to explore another possible therapeutic application of CD4 in AIDS--the use of recombinant soluble CD4 (rsCD4) as an immunogen. SIVmac-infected rhesus monkeys immunized with human rsCD4 developed not only an anti-human CD4 but also an anti-rhesus monkey CD4 antibody response. Coincident with the generation of this antibody response, SIVmac could not be isolated easily from peripheral blood lymphocytes and bone marrow macrophages of these animals. Furthermore, the decreased number of both granulocyte/macrophage and erythrocyte colonies grown from the bone marrow of these immunized monkeys rose to normal levels. These findings suggest that a modified human CD4 molecule serving as an immunogen might elicit an antibody response in man that could induce a beneficial therapeutic response in HIV-infected individuals.     

Two elderly cases of nocturnal onset stroke with stenosis of carotid arteries during the treatment of hypertension

Two hypertensive elderly patients developed ischemic stroke during night-time after blood pressure reduction using antihypertensive drugs. Case 1 was a 67-year-old man and his blood pressure had been controlled at 120–140/55–80 mmHg by the administration of amlodipine besilate (5 mg per day). At 04:00 hours on 25 August 2000, he experienced left hemiparalysis and was brought to the hospital within 1 h of onset. He had severe stenosis of the right internal carotid artery. His left hemiparalysis showed stepwise worsening, and atherectomy of carotid artery was performed. Ambulatory blood pressure monitoring after the operation demonstrated that his systolic blood pressure fell to a minimum of 74 mmHg while he was asleep. Case 2 was a 69-year-old man who had developed nasal bleeding due to blood pressure elevation of 240/80 mmHg in January 2000. Strict blood pressure control using long-acting nifedipine (40 mg per day) and lisinopril (20 mg per day) was initiated. After his blood pressure had been controlled at 130–140/60–80 mmHg, he suffered sudden left hemiparesis at 01:00 on 4 November 2000, showing complete obstruction of the right internal carotid artery. In a patient with carotid artery stenosis, nocturnal hypotension can cause an ischemic stroke. Ambulatory blood pressure monitoring and carotid ultrasound detecting carotid stenosis would be useful to identify patients with a high risk of stroke among elderly hypertensive patients treated with antihypertensive medication.