Short‐wave infrared light imaging measures tissue moisture and distinguishes superficial from deep burns

Existing clinical approaches and tools to measure burn tissue destruction are limited resulting in misdiagnosis of injury depth in over 40% of cases. Thus, our objective in this study was to characterize the ability of short‐wave infrared (SWIR) imaging to detect moisture levels as a surrogate for tissue viability with resolution to differentiate between burns of various depths. To accomplish our aim, we constructed an imaging system consisting of a broad‐band Tungsten light source; 1,200‐, 1,650‐, 1,940‐, and 2,250‐nm wavelength filters; and a specialized SWIR camera. We initially used agar slabs to provide a baseline spectrum for SWIR light imaging and demonstrated the differential absorbance at the multiple wavelengths, with 1,940 nm being the highest absorbed wavelength. These spectral bands were then demonstrated to detect levels of moisture in inorganic and in vivo mice models. The multiwavelength SWIR imaging approach was used to diagnose depth of burns using an in vivo porcine burn model. Healthy and injured skin regions were imaged 72 hours after short (20 seconds) and long (60 seconds) burn application, and biopsies were extracted from those regions for histologic analysis. Burn depth analysis based on collagen coagulation histology confirmed the formation of superficial and deep burns. SWIR multispectral reflectance imaging showed enhanced intensity levels in long burned regions, which correlated with histology and distinguished between superficial and deep burns. This SWIR imaging method represents a novel, real‐time method to objectively distinguishing superficial from deep burns.     

The first case of combined heart-liver transplantation in a patient with alveolar echinococcosis

We report a rare case of liver alveolar echinococcosis with an invasion of the hepaticocaval confluence, inferior vena cava, pericardium, right atrium, atrial septum, and superior vena cava, and its successful treatment by combined heart-liver transplantation.     

Magnetically Induced Transparency in Media with Helical Dichroic Structure

In our paper, the magneto-optical properties of a dichroic cholesteric liquid crystal layer with large values of magneto-optical parameter g and low values of dielectric permittivity were investigated. The solutions of the dispersion equation and their peculiarities were investigated in detail. The specific properties of reflection, transmission, absorption, rotation, ellipticity spectra and also the spectra of ellipticity and azimuth of eigen polarization were investigated. The existence of a tunable linear and nonreciprocal transmission band was shown.     

Noninvasive Assessment of the Fractional Flow Reserve with the CT FFRc 1D Method: Final Results of a Pilot Study

Background:Until recently, Russia did not utilize noninvasive fractional flow reserve (FFR) assessment. We developed an automated algorithm for noninvasive assessment of FFR based on a one-dimensional (1D) mathematical modeling.Objective:The research aims to evaluate the diagnostic accuracy of this algorithm.Methods:The study enrolled 80 patients: 16 of them underwent 64-slice computed tomography – included retrospectively, 64 – prospectively, with a 640-slice CT scan. Specialists processed CT images and evaluated noninvasive FFR. Ischemia was confirmed if FFR < 0.80 and disproved if FFR ≥ 0.80. The prospective group of patients was hospitalized for invasive FFR assessment as a reference standard. If ischemic, patients underwent stent implantation. In the retrospective group, patients already had invasive FFR values.Statistical analysis was performed using GraphPad Prism 8. We compared two methods using a Bland–Altman plot and per-vessel ROC curve analysis. Considering the abnormality of distribution by the Kolmogorov-Smirnov test, we have used Spearman’s rank correlation coefficient.Results:During data processing, three patients of the retrospective and 46 patients of the prospective group were excluded. The sensitivity of our method was 66.67% (95% CI: 46.71–82.03); the specificity was 78.95% (95% CI: 56.67–91.49), p = 0.0052, in the per-vessel analysis. In per-patient analysis, the sensitivity was 69.57% (95% CI: 49.13–84.40); the specificity was 87.50% (95% CI: 52.91–99.36), p = 0.0109. The area under the ROC curve in the per-vessel analysis was 77.52% (95% CI: 66.97–88.08), p < 0.0001.Conclusion:The obtained indices of sensitivity, specificity, PPV, and NPV are, in general, comparable to those in other studies. Moreover, the noninvasive values of FFR yielded a high correlation coefficient with the invasive values. However, the AUC was not high enough, 77.52 (95% CI: 66.97–88.08), p < 0.0001. The discrepancy is probably attributed to the initial data heterogeneity and low statistical power.     

Prospects for Electrical Performance Tuning in Ca3Co4O9 Materials by Metallic Fe and Ni Particles Additions

This work further explores the possibilities for designing the high-temperature electrical performance of the thermoelectric Ca₃Co₄O₉ phase, by a composite approach involving separate metallic iron and nickel particles additions, and by employing two different sintering schemes, capable to promote the controlled interactions between the components, encouraged by our recent promising results obtained for similar cobalt additions. Iron and nickel were chosen because of their similarities with cobalt. The maximum power factor value of around 200 μWm⁻¹K⁻² at 925 K was achieved for the composite with the nominal nickel content of 3% vol., processed via the two-step sintering cycle, which provides the highest densification from this work. The effectiveness of the proposed approach was shown to be strongly dependent on the processing conditions and added amounts of metallic particles. Although the conventional one-step approach results in Fe- and Ni-containing composites with the major content of the thermoelectric Ca₃Co₄O₉ phase, their electrical performance was found to be significantly lower than for the Co-containing analogue, due to the presence of less-conducting phases and excessive porosity. In contrast, the relatively high performance of the composite with a nominal nickel content of 3% vol. processed via a two-step approach is related to the specific microstructural features from this sample, including minimal porosity and the presence of the Ca₂Co₂O₅ phase, which partially compensate the complete decomposition of the Ca₃Co₄O₉ matrix. The obtained results demonstrate different pathways to tailor the phase composition of Ca₃Co₄O₉-based materials, with a corresponding impact on the thermoelectric performance, and highlight the necessity of more controllable approaches for the phase composition tuning, including lower amounts and different morphologies of the dispersed metallic phases.     

The ringed esophagus

Abdominal Radiology -     

Water oxidation by photosystem II is the primary source of electrons for sustained H2 photoproduction in nutrient-replete green algae

The unicellular green alga Chlamydomonas reinhardtii is capable of photosynthetic H₂ production. H₂ evolution occurs under anaerobic conditions and is difficult to sustain due to 1) competition between [FeFe]-hydrogenase (H₂ase), the key enzyme responsible for H₂ metabolism in algae, and the Calvin–Benson–Bassham (CBB) cycle for photosynthetic reductants and 2) inactivation of H₂ase by O₂ coevolved in photosynthesis. Recently, we achieved sustainable H₂ photoproduction by shifting algae from continuous illumination to a train of short (1 s) light pulses, interrupted by longer (9 s) dark periods. This illumination regime prevents activation of the CBB cycle and redirects photosynthetic electrons to H₂ase. Employing membrane-inlet mass spectrometry and H218O, we now present clear evidence that efficient H₂ photoproduction in pulse-illuminated algae depends primarily on direct water biophotolysis, where water oxidation at the donor side of photosystem II (PSII) provides electrons for the reduction of protons by H₂ase downstream of photosystem I. This occurs exclusively in the absence of CO₂ fixation, while with the activation of the CBB cycle by longer (8 s) light pulses the H₂ photoproduction ceases and instead a slow overall H₂ uptake is observed. We also demonstrate that the loss of PSII activity in DCMU-treated algae or in PSII-deficient mutant cells can be partly compensated for by the indirect (PSII-independent) H₂ photoproduction pathway, but only for a short (<1 h) period. Thus, PSII activity is indispensable for a sustained process, where it is responsible for more than 92% of the final H₂ yield.

Many species of green algae have [FeFe]-hydrogenases (H₂ases) (1) that catalyze the reversible reduction of protons to molecular hydrogen:2H++2e−⇄H2.[1]Since [FeFe]-H₂ases are extremely O₂-sensitive (2), reaction 1 typically proceeds under anoxic conditions. With respect to H₂ metabolism, Chlamydomonas reinhardtii is the most studied alga. This alga possesses two [FeFe]-H₂ases in the chloroplast, HYDA1 and HYDA2 (3, 4). In the light, they accept electrons from photosynthetically reduced ferredoxin (FDX1) (5), while in the dark electrons come from the activity of pyruvate ferredoxin oxidoreductase (PFR1) (6). PFR1 catalyzes the oxidation of pyruvate to acetyl-CoA, and its activity is linked to H₂ase via FDX1 (7). Since [FeFe]-H₂ases interact with the photosynthetic electron transport chain at the level of ferredoxin, they may accept electrons originating both from water oxidation via the photosystem II (PSII)-dependent pathway (“direct water biophotolysis”) and from the degradation of organic substrates via a PSII-independent mechanism (“indirect water biophotolysis” or “indirect pathway”) (8). In the latter case, the reductants are supplied to the plastoquinone (PQ) pool by the type II NADPH dehydrogenase (NDA2), thus bypassing PSII (9, 10).The release of H₂ leads to a loss of metabolic energy. In healthy, actively growing C. reinhardtii cultures, H₂ production is therefore only a temporal phenomenon observed during dark anoxia and upon subsequent onset of illumination (11). In contrast to dark fermentation, H₂ photoproduction is a very efficient process that proceeds for only a short period of time (from a few seconds to a few minutes). Two theories have been developed to explain the short duration. The first is based on the oxygen sensitivity of H₂ases (12, 13). In the light, algae accumulate O₂ that is produced by water oxidation at PSII (14). As a result, H₂ photoproduction may cease over time (14, 15), and the duration of this process is reported to shorten with increased light intensity (16). Because of the negative correlation between the rates of H₂ photoproduction and O₂ evolution, the inhibition of H₂ases by O₂ is frequently quoted as the primary reason for the rapid loss in H₂ photoproduction after the onset of illumination (17).Alternatively, the loss in the H₂ photoproduction efficiency during illumination could be explained by the light-induced induction of competitive pathways, which may drain reducing equivalents away from the [FeFe]-H₂ase enzyme (18, 19). Candidates for this role are the Mehler-like reaction driven by flavodiiron proteins (FDPs) (15, 20, 21) and the Calvin–Benson–Bassham (CBB) cycle (22). Compelling evidence for the competition between these two pathways and H₂ production has been accumulated in recent studies (23–25). As CO₂ fixation provides the strongest sink for photosynthetic reductants, it should play a major role in the cessation of H₂ photoproduction in algae when the CBB cycle is active (19, 22).For preventing competition between the [FeFe]-H₂ases and the CBB cycle, we recently devised a pulse-illumination protocol that allows H₂ production in nutrient-replete algal cultures for up to 3 d (23). To achieve this, we specifically selected the duration of light pulses in the light/dark sequence to avoid activation of the CBB cycle, thus allowing for the redirection of photosynthetic electrons toward the [FeFe]-H₂ases. Typically, a train of 1- to 6-s light pulses interrupted by 9-s dark periods is sufficient for sustained H₂ photoproduction in C. reinhardtii cultures (23, 25). Our protocol thus differs from earlier pulse-illumination approaches that aimed at preventing the accumulation of O₂ in the cultures (26).While we could demonstrate competition of [FeFe]-H₂ase with FDPs (25), the origin of reductants for H₂ photoproduction in the pulse-illuminated algae remained unclear. The relatively high efficiency of the process suggests the involvement of water oxidation by PSII, and consequently the simultaneous production of H₂ and O₂. Although widely proposed in the current literature (8, 24), the presence of the direct water biophotolysis in H₂-producing green algae has not yet been proven by direct experimental data.In the present study, we provide clear evidence for the presence of PSII-dependent oxidation of ¹⁸O-labeled water H218O with concomitant evolution of ¹⁶O₂ and ^16,18O₂ during H₂ photoproduction in the pulse-illuminated green alga C. reinhardtii under anoxic conditions. O₂ evolution is balanced by light-dependent and light-independent respiration that sustains the anoxic condition. We also demonstrate that the loss of PSII activity in algae can be partly compensated by the PSII-independent H₂ photoproduction pathway. Nevertheless, the activity of PSII is indispensable for the sustained process, where it contributes to more than 92% of the final H₂ yield.     

Safety and immunogenicity of live attenuated influenza reassortant H5 vaccine (phase I–II clinical trials)

Objective Our studies aimed to evaluate in clinical trials the safety and immunogenicity of an H5 live influenza vaccine candidate obtained using classical reassortment techniques from a low pathogenicity avian influenza (LPAI) A/Duck/Potsdam/1402‐6/86(H5N2) virus and the cold‐adapted (ca) donor strain A/Leningrad/134/17/57(H2N2). Methods During Phase I–II clinical trials, volunteers received intranasally two doses of reassortant influenza vaccine strain A/17/Duck/Potsdam/86/92 (H5N2) 21 days apart. Clinical examination of all vaccinees was conducted 7 days post‐vaccination. Serum antibody responses were measured by hemagglutination‐inhibition and microneutralization and local antibodies were estimated using an enzyme‐linked immunosorbent assay test. Results The vaccine was safe and of low reactogenicity with no febrile reactions. After revaccination 47·1–54·8% of subjects showed ≥fourfold seroconversions of Hamagglutination inhibition (HAI) antibodies to the hemagglutinin (HA) antigen of the A/17/Duck/Potsdam/86/92 (H5N2) virus and 29·4–30·8% were seroconverted to the HA antigen of the reverse genetics reassortant A/Indonesia/05/2005 × PR8 IBCDC‐RG (H5N1). Virus‐neutralizing antibody levels in sera of volunteers were similar to those shown in HAI test. The virus‐specific nasal IgA antibody response after two vaccine doses demonstrated significant increases of ≥fourfold rise SIgA antibodies (65%) geometrical mean titers (16·0) and a rise in SIgA antibodies (2·8) compared with one dose. Conclusion The live attenuated influenza vaccine candidate prepared using the LPAI A(H5N2) strain was well tolerated and elicited serum and local immune responses. There was evident cross‐reactivity to the A(H5N1) strain in the HAI test.