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Background The World Health Organization (WHO) strongly suggests using corticosteroids in patients with severe coronavirus disease 2019 (COVID-19). Similarly, a large randomized controlled clinical trial (RCT) in the UK found that dexamethasone effectively reduced the mortality rate in severe COVID-19 patients. However, the safety profile of corticosteroids has been a controversial area of study. Case description A case of a COVID-19 patient is described and the clinical characteristics are observed as the mildly symptomatic patient progresses into a critically ill patient and during their dramatic improvement with corticosteroid therapy in the early stage of the deterioration process with COVID-19 pneumonia. Conclusion The most suitable timing and dosage for the use of corticosteroids to maximize its effect during the worsening of COVID-19 pneumonia are discussed. One of the main pathophysiological hypotheses for severe COVID-19 patients is related to cytokine storm and virus load, which can be effectively treated with corticosteroid therapy.

Background Ankle syndesmosis injury is difficult to diagnose accurately at the initial visit. Missed diagnosis or improper treatment can lead to chronic complications. Complete syndesmosis injury with a concomitant rupture of the interosseous membrane (IOM) is more unstable and severe. The relationship between this type of injury and Maisonneuve injury, in which the syndesmosis is also injured, has not been discussed in the literature previously. Case summary A 16-year-old patient sustained left medial malleolar fracture, and the associated inferior tibiofibular syndesmotic instability was overlooked. After open reduction and internal fixation of the medial malleolar fracture, inferior tibiofibular syndesmosis diastasis with IOM rupture was detected by auxiliary imaging. Secondary surgical intervention was performed to reduce anatomically and fix with two trans-syndesmosis screws. Twelve weeks later, the screws were removed. At the 6-mo follow-up, the patient gained full range of motion of the ankle. Conclusion Complete syndesmosis injury with IOM rupture should be considered Maisonneuve-type injury. Open reduction and internal fixation could obtain good outcomes.

X-ray metrology, including the metrological calibration of X-ray detectors, optical elements and sources, is important for many frontier science, such as X-ray astronomy, EUV-lithography, plasma physics. Among many types of X-ray sources, synchrotron-radiation is considered perfect for X-ray metrology, mainly due to that arbitrarily X-rays specifications can be tailored to meet the demands of metrological calibration of X-ray detectors and optical elements. As a consequence, many metrology beamlines around the world are built, upgrading or to be constructed, including the metrology sector to be constructed at High Energy Photon Source (HEPS). One reasonable way to access good metrological data is using a stable X-ray beam, which means that beam position as well as flux should be as constant as possible and the beamline configuration should be simple and robust to reduce the uncertainty from beamline itself. In addition, the spectral purity of monochromatic X-rays is another crucial factor for X-ray metrology, which means stray X-rays and harmonic X-rays must be as low as possible. Many measures are taken to satisfy these requirements. An optical design of the metrology sector optimized for synchrotron-radiation-based- metrology is described here. The metrology sector, ranging from 50 eV to 20 keV, will be set up to meet the growing needs of X-ray metrology in China. All beamlines’ configurations are simple and easy to use, with an acceptable ratio of high-order harmonics and stray X-rays, which can be under 1% in the entire energy range.

Six Cd(II)/Mn(II)/Co(II)/Ni(II)/Zn(II) coordination complexes are formulated as [Cd2(X2−)2(μ3-O)2/3]n (1), [Mn2(X2−)2(μ3-O)2/3]n (2), {[Co1.5(Y4−)0.5(4,4′-bpy)1.5(OH−)]·2H2O}n (3), {[Ni(X2−)(4,4′-bpy)(H2O)2]·4H2O}n (4), [Zn(m-bdc2−)(bebiyh)]n (5), and [Cd(5-tbia2−)(bebiyh)]n (6) (H2X = 3,3′-(2,3,5,6-tetramethyl-1,4-phenylene) dipropionic acid. H4Y = 2,2′-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene) dimalonic acid, bebiyh = 1,6-bis(2-ethyl-1H-benzo[d]imidazol-1-yl)hexane, m-H2bdc = 1,3-benzenedicarboxylic acid, and 5-H2tbia = 5-(tert-butyl)isophthalic acid) were obtained by hydrothermal reactions and structurally characterized. Complexes 1 and 2 have a 6-connected 3D architecture and with several point symbols of (36·46·53). Complex 3 features a 5-connected 3D net structure with a point symbol of (5·69). Complex 4 possesses a 4-connected 2D net with a vertex symbol of (44·62). Complex 5 is a 3-connected 2D network with a point symbol of (63). Complex 6 is a (3,3)-connected 2D network with a point symbol of (63)2. In addition, complexes 1 and 4 present good photoluminescence behaviors. The electronic structures of 1 and 4 were investigated with the density functional theory (DFT) method to understand the photoluminescence behaviors.

Bronchopneumonia is a disease of the respiratory tract. It leads to other complications and endangers life and health. Long non-coding RNA (lncRNA) participates in the occurrence and development of bronchopneumonia. Nuclear paraspeckle assembly transcript 1 (NEAT1) plays a key role in inflammatory diseases, but the function of NEAT1 in bronchopneumonia remains unclear.RT-qPCR and Western blotting were performed to determine genes and proteins expressions. MTT was applied to test cell viability. Cell apoptosis was detected by flow cytometry. RIP was used to investigate the correlation between NEAT1 and miR-155-5p. The interaction between miR-155-5p and NEAT1 or MyD88 was evaluated by the dual-luciferase reporter gene.NEAT1 and MyD88 were upregulated in BEAS-2B cells by LPS, while miR-155-5p was downregulated. Knockdown of NEAT1 inhibited LPS-induced BEAS-2B cells growth inhibition by inhibiting the apoptosis. In addition, NEAT1 silencing suppressed LPS-induced inflammatory responses in BEAS-2B cells via suppression of TNF-α, IL-1β, IL-6, and IL-18. Meanwhile, NEAT1 is directly bound to miR-155-5p to regulate MyD88/NF-κB axis, and overexpression of miR-155-5p increased cell proliferation and suppressed inflammatory factors expression levels and cell apoptosis. Furthermore, sh-NEAT1-induced inhibition of BEAS-2B cells injury was partially reversed by miR-155-5p inhibitor or MyD88 overexpression.NEAT1 silencing suppressed LPS-induced BEAS-2B cells injury and inflammation by the mediation of miR-155-5p/MyD88/NF-κB axis. Thus, our study might shed new light on exploring the new strategies for the treatment of bronchopneumonia.

Background Langerhans cell histiocytosis (LCH) is a rare condition wherein Langerhans cells proliferate abnormally, adversely impacting organs including lymph nodes, bones, skin, lungs, and pituitary gland. The LCH disease course varies widely among patients from a self-limiting condition to one that progresses rapidly and culminates in death. It is uncommon for multisystem LCH to be observed in adults. Herein we describe a woman suffering from multi-system LCH involvement. Case summary A 37-year old Chinese woman was admitted to the hospital in June 2019 suffering from dyspnea that had progressed over the course of 5 years. Her medical history included: central diabetes insipidus (DI) that had been treated via radiotherapy, desmopressin acetate, and bromocriptine; bilateral pneumothorax with two surgeries having been performed to remove bullae; and autoimmune hepatitis that had been unsuccessfully treated using a combination of methylprednisolone and mycophenolate mofetil. A chest computed tomography (CT) scan revealed the presence of multiple pulmonary cysts of varying sizes. We re-analyzed right pulmonary bullae samples that had been removed in 2014, performed a systematic 18F-FDG PET/CT analysis, and convened a multidisciplinary medical team to diagnose and treat this patient. As a result, we were able to eventually diagnose this patient with LCH that was not associated with BRAF-V600E mutations. Conclusion We hope to emphasize the importance of systemic evaluation and of cooperation between multidisciplinary physicians with the goal of improving awareness and detection of this orphan disease.

The dendrite arm spacing in the continuous casting slab of Mn13 steel under different casting speeds was measured using the metallographic microscope. Meanwhile, a heat transfer model was established by the Pro-cast software. The relationship between the dendrite arm spacing and casting speed in continuous casting slab of Mn13 steel was studied and described by a function expression. The results provide an important theoretical basis for the development and optimization of continuous casting production process of high-manganese steel and help to improve the quality of continuous casting slab of high-manganese steel. Under the experimental conditions, the suitable casting speed is about 0.9 m/min. The secondary dendrite spacing maintains a relatively stable low-amplitude increase trend, and it is beneficial to obtain a higher proportion of equiaxed crystals.

Absolute measurement of radiant power in the X-ray region is essential for many applications in astrophysics, spectroscopy, and X-ray diagnostics. This paper presents a dependable method of absolute measurement of radiant power for synchrotron radiation monochromatized X-rays. A free-air ionization chamber was examined closely and employed as the detector in the present work. Its measuring principle was discussed, and the correction factors were determined. Absolute measurement of radiant power for synchrotron radiation monochromatized X-rays in the region of 6–20 keV was performed using the free-air ionization chamber at Beijing Synchrotron Radiation Facility. As a verification and an important application, photodiodes were calibrated against the free-air ionization chamber. Relative standard uncertainties of absolute measurement using free-air ionization chamber are about 1%. Calibration of photodiodes within the photon energy range from 6 to 20 keV has relative standard uncertainties below 1.5%. The free-air ionization chamber is qualified to be used in many disciplines to support the measurement of optical radiation.

Nonwoven nanowire network fabrics of the material class La1−xSrxMnO3 (LSMO) with x = 0.2 were fabricated employing a sol-gel-process via electrospinning and a subsequent thermal treatment process based on thermal gravity analysis results. Investigations by means of scanning electron microscopy revealed an average diameter of the resulting nanowires of around 230 nm and a length of more than 100 μm. The chemical phases of the samples have been confirmed via X-Ray diffraction. The nanowires are polycrystalline with an average grain size of about 25 nm obtained from transmission electron microscopy. Analyses of the electronic transportation properties and of the magnetoresistive (MR) effects of the nanowire samples were carried out by a four probe measurement inside a bath cryostat in fields up to 10 T. Measurements of magnetization in the temperature range 2 K

The paper shows fundamental possibility of processing of gold-bearing technogenic raw materials using the method of electric explosion. A series of experiments using a laboratory and pilot-production high-voltage pulsed discharge (HVPD) installation for the processes of enrichment of gold-bearing mineral raw materials of Komsomolsk mine tailings in Kemerovo region is conducted with a relatively low energy electrical discharge in the pulse of up to 112.5 Joules and the cost of electric power of about 1.5 kW/ton of raw material, that allows complete destruction of clay components agglomerations to less than 0.045 mm (micron and submicron sizes). Solid minerals such as quartz are simultaneously destroyed by defects in the grains and withdrawn from the installation with water, thus increasing gold degree of the concentrate. The results of particle-size and X-ray structural analyses of gold-bearing mineral raw materials of Komsomolsk mine tailings in Kemerovo region obtained by the method of electric explosion are discussed.

BackgroundBrain metastasis mainly originates from lung cancer. Napsin A and TTF-1 factors have frequently been detected in lung adenocarcinoma cases. Brain metastasis tumors with napsin A and TTF-1 positive are easily classified as lung adenocarcinoma origin. However, some thyroid cancers also exhibit these clinical features. Besides, lung is the most common metastasis of undifferential thyroid cancer. Therefore, it requires development of novel diagnostic tools to aid in distinguishing between pulmonary and thyroid origin.Patient FindingsWe reported a case that was initially diagnosed as brain metastatic lung cancer based on immunohistochemistry results. Analysis of next-generation sequencing (NGS) data from the brain lesion revealed that the cancer may have originated from the thyroid. We detected combo mutations in TERT promoter mutation, RET fusion and TP53, which are common in undifferential thyroid cancer (UTC), but rare for lung cancer. These results, coupled with identification of PAX8, indicated that this patient had UTC. Additionally, her three sons, despite being asymptomatic, were all diagnosed with papillary thyroid carcinoma.SummaryThe patient received anlotinib treatment and showed good clinical outcomes. One month after anlotinib treatment, the pulmonary nodules were found to be controlled, and the thyroid tumor drastically reduced, and tracheal compression relieved. She continued anlotinib treatment for the following two months, but died one month later because the treatment stopped owing to financial reasons. All her sons underwent total thyroidectomy with lymph node dissection.ConclusionsAlthough NGS has been reported to assist in diagnosis of the origin of some tumors, this is the first evidence of NGS for the determination of the origin of thyroid tumors. To our knowledge, this is the first time that a combination of multiple mutations has been used to help determine the origin of a tumor, compared with the previous single mutant gene. Moreover, this is the first evidence on the use of anlotinib for treatment of UTC with distant metastasis. Besides, all three sons of the patient had thyroid carcinoma in subsequent examinations, indicating high-risk for familial non-medullary thyroid cancer in UTC patients and necessity for performing thyroid ultrasound testing in other family members.

Municipal wastewater methanogenesis is one of the ways to utilize municipal wastewater resources.In this study, a biofilter used to treat actual municipal wastewater was employed to investigate the methanogenesis in a pilot-scale reactor. The method of rapid start-up, the influence of temperature on the reactor performance, and the changes in the microbial structure were investigated in the pilot-scale study. The rapid start-up of the biofilter reactor was achieved by the combination of intermittent and continuous operations. The effluent concentration of SCOD was 60 mg ·L

Background: The World Health Organization (WHO) recommends using corticosteroids in patients with severe coronavirus disease 2019 (COVID-19) and acute respiratory distress syndrome (ARDS), and a large randomized controlled clinical trial in the UK found that dexamethasone was effective in reducing the number of deaths in patients with severe COVID-19.Case presentation: Herein, we described a case of COVID-19 with the clinical characteristics of the mild-symptomatic stage deteriorating to a critically ill state, who showed dramatic improvement with corticosteroids in the early stage of worsening of COVID-19 pneumonia.Discussion: This article further discusses the most suitable timing and dosage of corticosteroid to maximize its effect during the worsening of COVID-19 pneumonia.Learning points:• One of the main pathophysiological hypotheses for severe COVID-19 pneumonia is related to cytokine storm and viral load.• The clinical factors should be considered as the initial sign of a cytokine storm, and corticosteroid therapy may be useful in these patients.

Objectives Little is known about the roles of integral membrane proteins beyond channels, carriers or receptors in meiotic oocytes. The transmembrane protein Fam70A was previously identified as a likely “female fertility factor” in Fox3a‐knockout mouse ovaries where almost all follicles underwent synchronous activation and the mice became infertile very early. However, whether Fam70A functions in oocyte meiosis remains unknown. Therefore, the present study aimed to address this question. Materials and Methods Co‐immunoprecipitation, immunogold labelling‐electron microscopy, co‐localization and yeast two‐hybrid assays were used to verify the interaction. Antibody or small interfering RNA transfection was used to deplete the proteins. Immunofluorescence, immunohistochemistry and live tracker staining were used to examine the localization or characterize phenotypes. Western blot was used to examine the protein level. Results Fam70A was enriched in oocyte membranes important for normal meiosis. Fam70A depletion remarkably disrupted spindle assembly, chromosome congression and first polar body extrusion, which subsequently increased aneuploidy and abnormal fertilization. Moreover, Fam70A directly bound Wnt5a, the most abundant Wnt member within oocytes. Depletion of either Fam70A or Wnt5a remarkably increased adenomatous polyposis coli (APC), which stabilizes active β‐catenin and microtubules. Consequently, depletion of either Fam70A or Wnt5a remarkably increased p‐β‐catenin (inactive form) and acetylated tubulin, while APC knockdown remarkably decreased these two. Furthermore, Fam70A depletion remarkably reduced Akt phosphorylation. Conclusions Fam70A regulates meiosis and quality of mouse oocytes through both canonical and non‐canonical Wnt5a signalling pathways.

To explore the regularity of traditional Chinese patent medicines for the treatment of hyperlipidemia recorded in Newly Edited National Chinese Traditional Patent Medicines,the Composition Principles of Chinese Patent Drugs,New Drug Conversion Standard,the Compilation of National Standard for Traditional Chinese Medicines and Chinese Pharmacopoeia. Researchers extracted the information of prescriptions from these cases according to the inclusion and exclusion criteria. Then microsoft excel 2010 was used to conduct frequency statistics and count the frequency of traditional Chinese medicine. SPSS Clementine( ver.12. 0) and SPSS( ver. 18. 0)were adopted respectively for frequency analysis,association rules analysis,cluster analysis and factor analysis. Besides,KMO test and Bartlett spherical test were performed for factor adaptation test. Finally,a total of 173 traditional Chinese medicines were included,involving 94 Chinese patent medicine prescriptions. The frequency results of traditional Chinese medicine showed that there were 33 kinds of high-frequency traditional Chinese medicine,mainly including those for tonifying medicine,activating blood and resolving stasis and blood-stasis,and clearing damp. The association rules analysis found out 12 association rules of drug pairs,3-herb pairs of 25 and4-herb pairs of 6. Totally 11 medicine groups with relevance were respectively extracted by cluster analysis. KMO test and Bartlett spherical test indicated that the method was suitable for factor analysis and 11 common factors were respectively extracted by factor analysis. The association rules reflected the therapeutic method for tonify the liver and kidney,activating blood and resolving stasis. Cluster analysis and factor analysis showed the therapeutic method of Qi-enriching and Yin-nourishing,and the factor analysis focused more on removing blood stasis and dampness. The decision tree with hawthorn as the dependent variable reflects the importance of alisma orientalis and fructus schisandrae in the drug matching. In conclusion,data mining technique can comprehensively analyze the regularity of prescriptions of traditional Chinese patent medicine for hyperlipidemia,and is helpful for guiding the development of Chinese patent medicines and the clinical practice of traditional Chinese medicine.

Grain size is one of the key microstructural factors that control the mechanical properties of steels. The present work aims to extend the theories of grain refinement which were established for cast light alloys to steel systems. Using a designed Fe-4 wt pct Si alloy (all-ferrite structure during whole solidification process), the solute effect on grain refinement/grain coarsening in ferritic systems was comprehensively investigated. Experimental results showed that boron (B), which is associated with the highest Q value (growth restriction factor) in ferrite, significantly refined the as-cast structure of the Fe-4 wt pct Si alloy. Cu and Mo with low Q values had no effect on grain refinement. However, although Y and Zr have relatively high Q values, addition of these two solutes led to grain coarsening in the Fe-4Si alloy. Understanding the results in regards to the growth restriction factor and the driving force for the solidification led to the conclusion that in addition to the grain growth restriction effect, the changes of thermodynamic driving force for solidification due to the solute addition also played a key role in grain refinement in ferritic alloys.

A new grain refiner, LaB6, was identified for ferritic steels based on the crystallographic calculation using the edge-to-edge matching model. Addition of 0.5 wt pct LaB6 led to a reduction of the average grain size from 765 to 92 μm and the proportion of the columnar structure from 35 to 8 pct in an as-cast Fe-4Si ferritic alloy. Although LaB6 was supposed to act as an active inoculant for δ-ferrite, thermodynamic calculation indicated that LaB6 is not thermodynamically stable in the melt of the Fe-4Si alloy. It was subject to decompose into La and B solutes. Consequently, both La and B reacted with Fe, O and S, forming different compounds. Microstructural examination at room temperature observed La2SO2 and La2O3 particles within the ferrite grains and Fe2B along the grain boundaries in the samples. Through EBSD analysis, a reproducible orientation relationship between ferrite and La2SO2 was identified. In addition, the edge-to-edge matching calculation also predicted the high potency for La2SO2 to be an effective nucleant for δ-ferrite. It was considered that the grain refinement of LaB6 was attributed to the enhanced heterogeneous nucleation of δ-ferrite by La2SO2, and the solute effect of B due to the high Q-value in ferrite.

In this paper, we review the background and the recent development of the swimming pool-type low temperature heating reactor (SPLTHR). Particularly, we introduce the recent progress on the research of the technical feasibility, the economy, and the safety of the SPLTHR. Our conclusion suggests that the SPLTHR is mature in technique and competitive in economy. Moreover, it has an excellent inherent safety. We also propose a plan for the industry development of the SPLTHR.

Objective New therapeutic agents in combination with the standard Stupp protocol (a protocol about the temozolomide combined with radiotherapy treatment with glioblastoma was research by Stupp R in 2005) were assessed to evaluate whether they were superior to the Stupp protocol alone, to determine the optimum treatment regimen for patients with newly diagnosed glioblastoma. Patients and methods We implemented a search strategy to identify studies in the following databases: PubMed, Cochrane Library, EMBASE, CNKI, CBM, Wanfang, and VIP, and assessed the quality of extracted data from the trials included. Statistical software was used to perform network meta-analysis. Results The use of novel therapeutic agents in combination with the Stupp protocol were all shown to be superior than the Stupp protocol alone for the treatment of newly diagnosed glioblastoma, ranked as follows: cilengitide 2000 mg/5/week, bevacizumab in combination with irinotecan, nimotuzumab, bevacizumab, cilengitide 2000 mg/2/week, cytokine-induced killer cell immunotherapy, and the Stupp protocol. In terms of serious adverse effects, the intervention group showed a 29% increase in the incidence of adverse events compared with the control group (patients treated only with Stupp protocol) with a statistically significant difference (RR = 1.29; 95%CI 1.17–1.43; P 0.001). The most common adverse events were thrombocytopenia, lymphopenia, neutropenia, pneumonia, nausea, and vomiting, none of which were significantly different between the groups except for neutropenia, pneumonia, and embolism. Conclusions All intervention drugs evaluated in our study were superior to the Stupp protocol alone when used in combination with it. However, we could not conclusively confirm whether cilengitide 2000 mg/5/week was the optimum regime, as only one trial using this protocol was included in our study.

Osteosarcoma is the most common aggressive sarcoma of the bone in children and adolescents. It is characterized by a high level of genetic instability and recurrent DNA deletions and amplifications. microRNAs (miRNAs) play a key role in cancer initiation, progression and metastasis; however, the potential role of miRNAs in osteosarcoma remains largely unknown. In the present study, miR-433 was shown to be overexpressed in osteosarcoma tissues compared with normal human osteoblasts. Transfection of miR-433 mimics into osteosarcoma cell lines significantly decreased apoptosis by targeting programmed cell death 4, a tumor suppressor that is involved in apoptosis. In contrast, inhibition of miR-433 enhanced apoptosis. Furthermore, in vivo miR-433 overexpression inhibited the apoptosis of tumor cells and increased tumor growth. The results of the present study suggested that miR-433 is a potential molecular target for osteosarcoma therapy.

For the first time, single-crystal (SC), vertically-oriented and high-density electrospun ultrafine nanofiber/fibre bundles (NFBs) were achieved by the controlled postcalcination of as-spun fibers. The formation of high-density SC strontium carbonate (i.e. SrCO3) nanoneedles (NNs) quasi-vertically grown with an average diameter of ∼20 nm, several micrometers long that stand perpendicular to the growth surface, is demonstrated. Furthermore, under electron-beam irradiation, an individual as-calcined SC SrCO3 NN undergoes sequential structural transitions from the [110] SC—to—polycrystalline—to—[102] SC SrCO3 NN, which was revealed by in situ transmission electron microscopy. Photoluminescence quenching over the full solar spectrum range was observed in the as-calcined vertically-oriented SrCO3 NFBs.

An anthracene vapor-assisted inverse transport growth mechanism of unsupported ultrathin two-dimensional (2D) superconducting single-crystal niobium (Nb) and niobium diselenide (NbSe2) nanoplates (thickness ∼2.5 nm) using anthracene and NbSe2 powders as precursors is reported. Besides the whisker-like counterparts, the anthracene vapor hierarchical invasion into NbSe2 leads to 2D Nb nanoplates with a {110} surface and 2D few-layered {0001} NbSe2 nanoplates grown in the high-temperature residual region, while sub-millimeter selenium whiskers are found in the low-temperature transporting region. Direct magnetization measurements demonstrated that superconductivity at ∼3.3 K was clearly observed in the unsupported ultrathin Nb and NbSe2 nanoplates. These findings may offer a new way to produce freestanding single-crystal 2D superconductors and elemental 2D metallic nanoplates.

A vertically-oriented growth of the monolithic ZnO nanocrystals (NCs)-on-nanoneedle (NN) single-crystalline (SC) hybrids is presented with intrinsic nanoscale complexity, consisting of spatially homogeneously distributed ultrahigh-density (2.0 × 104 μm−2) on-site homoepitaxial growth of 4 nm ZnO NCs on the surface of vertically oriented high-density (8 × 108 cm−2) SC [100] ZnO NNs. The electron-beam stimulated “self-additive on-surface oxidation-limited growth” at room temperature is proposed for the on-site growth of numerous ZnO NCs on the (0001) facets of a single ZnO NN. Compared with heterojunctions, the unprecedented compact monolithic ZnO NCs-on-NN SC hybrids, growing from the inside out, may hold great promise for enhanced photovoltaic performance (e.g., electron mobility) of ZnO NC-sensitized solar cells.