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The practical applications of perovskite solar cells (PSCs) are limited by further improvement of their stability and performance. Additive engineering and interface engineering are promising medicine to cure this stubborn disease. Herein, an alkali metal fluoride as an additive is introduced into the tin oxide (SnO2) electron transport layer (ETL). The formation of coordination bonds of F- ions with the oxygen vacancy of Sn4+ ions decreases the trap-state density and improves the electron mobility; the hydrogen bond interaction between the F ion and amine group (FA+) of perovskite inhibits the diffusion of organic cations and promotes perovskite (PVK) stability. Meanwhile, the alkali metal ions (K+, Rb+, and Cs+) permeated into PVK fill the organic cation vacancies and ameliorate the crystal quality of PVK films. Consequently, a SnO2-based planar PSC exhibits a power conversion efficiency (PCE) of 20.24%, while the PSC modified by CsF achieves a PCE of 22.51%, accompanied by effective enhancement of stability and negligible hysteresis. The research results provide a typical example for low-cost and multifunctional additives in high-performance PSCs.

Hole transporting materials (HTMs) play an unparalleled role in heightening the stability and photovoltaic performance of perovskite solar cells (PSCs). The organic small molecule spiro-OMeTAD is frequently utilized for HTM in PSCs. However, the raw spiro-OMeTAD without dopant would be harmful to the development of highly efficient PSCs, due to its unsatisfied hole mobility and conductivity. Therefore, we introduce an inorganic dopant (chromium trioxide, CrO3) into the lithium-salt doped spiro-OMeTAD. Because of the exclamatory oxidizability of CrO3, it can accelerate the oxidation of spiro-OMeTAD and thereby enhancing the hole mobility of HTM. The introduction of CrO3 not only substantially decreases the density of defects, but also adjusts spiro-OMeTAD energy band, and thus effectively suppresses the hysteresis and improving stability of PSCs. In the end, we obtained a power conversion efficiency (PCE) as high as 22.6% after doping CrO3 in spiro-OMeTAD. The facile, low cost and outstanding photovoltaic performance render CrO3 an excellent dopant for HTMs in PSCs.

Similar to the recent COVID-19 pandemic, influenza A virus poses a constant threat to the global community. For the treatment of flu disease, both antivirals and vaccines are available with vaccines the most effective and safest approach. In order to overcome limitations in egg-based vaccine manufacturing, cell culture–based processes have been established. While this production method avoids egg-associated risks in face of pandemics, process intensification using animal suspension cells in high cell density perfusion cultures should allow to further increase manufacturing capacities worldwide. In this work, we demonstrate the development of a perfusion process using Madin-Darby canine kidney (MDCK) suspension cells for influenza A (H1N1) virus production from scale-down shake flask cultivations to laboratory scale stirred tank bioreactors. Shake flask cultivations using semi-perfusion mode enabled high-yield virus harvests (4.25 log10(HAU/100 μL)) from MDCK cells grown up to 41 × 106 cells/mL. Scale-up to bioreactors with an alternating tangential flow (ATF) perfusion system required optimization of pH control and implementation of a temperature shift during the infection phase. Use of a capacitance probe for on-line perfusion control allowed to minimize medium consumption. This contributed to a better process control and a more economical performance while maintaining a maximum virus titer of 4.37 log10(HAU/100 μL) and an infectious virus titer of 1.83 × 1010 virions/mL. Overall, this study clearly demonstrates recent advances in cell culture–based perfusion processes for next-generation high-yield influenza vaccine manufacturing for pandemic preparedness. Key points • First MDCK suspension cell–based perfusion process for IAV produciton was established. • “Cell density effect” was overcome and process was intensified by reduction of medium use and automated process control. • The process achieved cell density over 40 × 106 cells/mL and virus yield over 4.37 log10(HAU/100 μL). Supplementary Information The online version contains supplementary material available at 10.1007/s00253-020-11050-8.

Perovskite solar cells have developed rapidly in the past decades. However, there are large amounts of ionic defects at the surface and grain boundaries of perovskite films which are detrimental to both the efficiency and stability of perovskite solar cells. Here, an organic halide salt pyridinium iodide (PyI) is used in cation–anion-mixed perovskite for surface defect passivation. Different from the treatment with Lewis base pyridine (Py) which can only bind to the under-coordinated Pb ions, zwitterion molecule PyI can not only fill negative charged iodine vacancies, but also interact with positive charged defects. Compared with Py treatment, PyI treatment results in smoother surface, less defect densities and non-radiative recombination in perovskite, leading to an improved VOC, negligible J–V hysteresis and stable performance of devices. As a result, the champion PyI-treated planar perovskite solar cell with a high VOC of 1.187 V achieves an efficiency of 21.42%, which is higher than 20.37% of Py-treated device, while the pristine device without any treatment gets an efficiency of 18.83% at the same experiment conditions.

Influenza is a global public health issue leading to widespread morbidity and mortality with devastating economic loss annually. Madin-Darby Canine Kidney (MDCK) cell line has been a major cell line for influenza vaccine applications. Though many details of the host metabolic responses upon influenza A virus (IAV) infection have been documented, little is known about the metabolic reprogramming features of a hyper-productive host for IAV vaccine production. In this study, a MDCK cell clone H1 was shown to have a particular high productivity of 30 × 10

Subunit vaccines with high purity and safety are gradually becoming a main trend in vaccinology. However, adjuvants such as interferon-gamma (IFN-γ) are required to enhance immune responses of subunit vaccines due to their poor immunogenicity. The conjugation of antigen with adjuvant can induce more potent immune responses compared to the mixture of antigen and adjuvant. At the same time, the selection of linker, indispensable in the construction of the stable and bioactive fusion proteins, is complicated and time-consuming. The development of immunoinformatics and structural vaccinology approaches provides a means to address the abovementioned problem. Therefore, in this study, a E2-IFN-γ fusion protein with an optimal linker (E2-R2-PIFN) was designed by bioinformatics approaches to improve the immunogenicity of the classical swine fever virus (CSFV) E2 subunit vaccine. Moreover, the E2-R2-PIFN fusion protein was expressed in HEK293T cells and the biological effects of IFN-γ in E2-R2-PIFN were confirmed in vitro via Western blotting. Here, an alternative method is utilized to simplify the design and validation of the antigen-adjuvant fusion protein, providing a potential subunit vaccine candidate against CSFV. KEY POINTS: • An effective and simple workflow of antigen-adjuvant fusion protein design and validation was established by immunoinformatics and structural vaccinology. • A novel E2-IFN-γ fusion protein with an optimal linker was designed as a potential CSFV vaccine. • The bioactivity of the newly designed fusion protein was preliminarily validated through in vitro experiments.

The carrier non-radiative recombination and instability of device caused by the inherent defects are main factors limiting development of perovskite solar cells (PSCs). During the fabrication process of a PSC device, perovskite films often produce Pb0 and I0 defects. This paper reports a strategy for synergistic optimization of perovskite films by defects passivation and surface modification. The doping of phthalide (PT) in the Pb-rich (CH(NH2 )2 )1-x (CH3 NH3 )x PbI3 film can passivate lead cation defects, and the modification of 1-iodooctadecane (1-IO) can reduce halogen anion defects and improve stability of PSCs owing to its hydrophobicity. The PT and 1-IO optimized device achieves a power conversion efficiency (PCE) of 22.27%. The optimized PSCs remain 93.2% of the initial PCE when placed in air environment (relative humidity of 10%, 25 °C) more than 70 days. The PT and 1-IO synergistic optimization provides a novel strategy for improving the performance and stability of PSCs.

Titania (TiO2) has wide applications in the realm of perovskite solar cells (PSCs). Because high-temperature processing severely limits the application of flexible and tandem devices, it is signifi...

The introduction of upconversion materials as spectral converter into photovoltaic devices to harvest and convert near infrared photons to visible photons that can thus be absorbed by perovskite layer is a promising strategy for enhancing the performance of perovskite solar cells. Hence, β-NaYF4:Yb3+/Er3+/Sc3+@NaYF4 rare-earth doped upconversion nanoparticles with core-shell structure are synthesized. The doped rare-earth ions Yb3+ and Er3+ convert near infrared light to red and green light, and the Sc3+ ions enhance the upconversion luminescence efficiency, which broaden the absorption range of solar irradiation and generate extra photocurrent in the solar cells. The surface defects of β-NaYF4:Yb3+/Er3+/Sc3+ is passivated by the even NaYF4 shell, which results in the obvious enhancement in upconversion emission intensity. Consequently, the perovskite solar cell based on the rare-earth doped upconversion nanoparticle mesoporous layer achieves a high power conversion efficiency of 20.19%, while the device based on TiO2 mesoporous layer gets an efficiency of 17.44%.

Sialylation affects circulating half-life, charge distribution, and other biochemical properties of therapeutic glycoproteins. Loss of protein sialylation during glycoprotein-producing bioprocesses could lead to a low final protein sialylation level and bring negative effects on subsequent clinical efficacy. In this work, an Fc-fusion protein-producing Chinese hamster ovary cell fed-batch culture process was studied and insights into the loss of protein sialylation during the Fc-fusion protein production phase (days 5 to 13) were presented. The results showed that the decreased total sialic acid content was 13.84 μg/mg during the production phase, which accounted for 24% of the total sialic acid content on day 5. The lost sialic acids were predominantly from α 2-3 sialylation on N- and O-glycans. Through cell-free incubation and kinetics studies, it was found that the decreased sialic acid content caused by extracellular sialic acid degradation and incomplete glycan biosynthesis were 7.79 μg/mg and 6.05 μg/mg, respectively. The two processes had a nearly equal contribution to the loss of final product sialylation. Detailed characterizations revealed that decreases in sialic acid content were due either to extracellular sialic acid degradation via hydrolysis of α 2-3 sialic acids probably by released cytosolic sialidase or to a lack of galactosylated glycan availability for sialylation during late-stage glycosylation. Our work provides a better understanding of losses in protein sialylation during glycoprotein manufacturing.

Seasonal influenza epidemics occur both in northern and southern hemispheres every year. Despite the differences in influenza virus surface antigens and virulence of seasonal subtypes, manufacturers are well-adapted to respond to this periodical vaccine demand. Due to decades of influenza virus research, the development of new influenza vaccines is relatively straight forward. In similarity with the ongoing coronavirus disease 2019 pandemic, vaccine manufacturing is a major bottleneck for a rapid supply of the billions of doses required worldwide. In particular, egg-based vaccine production would be difficult to schedule and shortages of other egg-based vaccines with high demands also have to be anticipated. Cell culture-based production systems enable the manufacturing of large amounts of vaccines within a short time frame and expand significantly our options to respond to pandemics and emerging viral diseases. In this study, we present an integrated process for the production of inactivated influenza A virus vaccines based on a Madin-Darby Canine Kidney (MDCK) suspension cell line cultivated in a chemically defined medium. Very high titers of 3.6 log10 (HAU/100 µl) were achieved using fast-growing MDCK cells at concentrations up to 9.5 × 106 cells/ml infected with influenza A/PR/8/34 H1N1 virus in 1 L stirred tank bioreactors. A combination of membrane-based steric-exclusion chromatography followed by pseudo-affinity chromatography with a sulfated cellulose membrane adsorber enabled full recovery for the virus capture step and up to 80% recovery for the virus polishing step. Purified virus particles showed a homogenous size distribution with a mean diameter of 80 nm. Based on a monovalent dose of 15 µg hemagglutinin (single-radial immunodiffusion assay), the level of total protein and host cell DNA was 58 µg and 10 ng, respectively. Furthermore, all process steps can be fully scaled up to industrial quantities for commercial manufacturing of either seasonal or pandemic influenza virus vaccines. Fast production of up to 300 vaccine doses per liter within 4-5 days makes this process competitive not only to other cell-based processes but to egg-based processes as well.

Seasonal influenza infection waves occur both in northern and southern hemispheres every year. Despite the differences in influenza virus surface antigens and virulence of seasonal subtypes, manufacturers are well-adapted to respond to this periodical vaccine demand. Due to decades of influenza virus research, the development of new influenza vaccines is relatively straight-forward. Nevertheless, compared to the recent Covid-19 pandemic where a vaccine is not yet available, influenza vaccine manufacturing would be a major bottleneck for the rapid supply of billions of doses required worldwide. In particular, egg-based vaccine production would be difficult to schedule and shortages of other egg-based vaccines with high demands also have to be anticipated. Cell culture-based production systems enable manufacturing of large amounts of vaccines within a short time frame and expand significantly our options to respond to pandemics and emerging viral diseases. In this work, we present an integrated process for the production of inactivated influenza A virus vaccines based on a MDCK suspension cell line cultivated in a chemically defined medium. Very high titers of 3.6 log10(HAU/100 µL) were achieved using fast growing MDCK cells at concentrations up to 9.5 × 106 cells/mL infected with influenza A/PR/8/34 H1N1 virus in 1 L stirred tank bioreactors. A combination of two membrane-based chromatography steps enabled full recovery for the virus capture and up to 80 % recovery for the virus polishing step, respectively. Purified virus particles showed a homogenous size distribution around a mean diameter of 80 nm. Based on a monovalent dose of 15 µg hemagglutinin (SRID assay), the level of total protein was 58 µg and the level of host cell DNA contamination was below 10 ng. Furthermore, all process steps can be fully scaled up to industrial quantities for commercial manufacturing of either seasonal or pandemic influenza virus vaccines. Fast production of up to 300 vaccine doses per liter within 4 to 5 days makes this process competitive not only to other cell-based processes, but to egg-based processes as well.

Migraine is a disease whose aetiology and mechanism are not yet clear. Chuanxiong Rhizoma (CR) is employed in traditional Chinese medicine (TCM) to treat various disorders. CR is effective for migraine, but its active compounds, drug targets, and exact molecular mechanism remain unclear. In this study, we used the method of systems pharmacology to address the above issues. We first established the drug-compound-target-disease (D-C-T-D) network and protein-protein interaction (PPI) network related to the treatment of migraine with CR and then established gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The results suggest that the treatment process may be related to the regulation of inflammation and neural activity. The docking results also revealed that PTGS2 and TRPV1 could directly bind to the active compounds that could regulate them. In addition, we found that CR affected 11 targets that were more highly expressed in the liver or heart but were the lowest in the whole brain. It also expounds the description of CR channel tropism in TCM theory from these angles. These findings not only indicate that CR can be developed as a potential effective drug for the treatment of migraine but also demonstrate the application of systems pharmacology in the discovery of herbal-based disease therapies.

Mica epoxy insulation as used for generator stator windings is required to be improved as regards withstand electrical stress and heat dissipation. Replacement of epoxy resins by epoxy nanocomposites is a useful method to fulfil a purpose of such improvement. This paper is aimed to evaluate PD-initiated breakdown (BD) performances as one of the most crucial characteristics using simulated model specimens. Two constituent materials, i.e. mica tapes and resin layers were set as about 40 and 10 µm in thickness, respectively. EDX analysis shows that the model specimens include silica nanofillers properly dispersed in narrow nanocomposite regions and are suitable for PD initiated BD experiments. It was found that PD initiated BD lifetime was 2.8 times in nanocomposites than in neat epoxy under a rather high electric stress condition.

Arsenic is a toxic metalloid, which also compromises immunity and causes various immunological disorders. Exposure to arsenic exerts the immunosuppressive properties of dendritic cells (DCs). Autophagy is a self-renewal process of cells, which degrades damaged macromolecules and organelles through the lysosomal pathway. Thus, herein, we attempt to clarify the impacts of autophagy and the autophagy–lysosome pathway on arsenic-exposed DCs. Bone marrow-derived dendritic cells (BMDCs) were exposed to different concentrations of arsenic (0.25, 0.5 and 1 μM) with or without LPS stimulation. Initially, we observed that arsenic induced autophagosome accumulation, significantly enhanced the LC3 II and p62 expressions and down-regulated the p-mTOR protein levels. We also determined that arsenic-induced autophagy occurred via an mTOR pathway. The results further revealed that arsenic inhibited autophagic flux in LPS-stimulated BMDCs using the autophagy inhibitor chloroquine (CQ). Meanwhile, arsenic significantly decreased the number of lysosomes, protein expression of lysosomal-specific markers LAMP1 and LAMP2, and the protein levels of lysosomal cysteine cathepsins (CTSD and CTSL). Moreover, the overexpression of transcription factor EB (TFEB), the master transcriptional regulator of autophagy and lysosome biogenesis, partially relieved arsenic-inhibited lysosomal CTSD and CTSL expressions, recovered the disorder of autophagic flux, promoted the production of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-12, and reduced anti-inflammatory cytokine IL-10 secretion. In summary, our results support the idea that arsenic induces autophagy through an mTOR-dependent pathway in cultured BMDCs. Meanwhile, arsenic weakens the process of autophagic flux, which may be partially due to lysosomal dysfunction. Furthermore, we also suggest that TFEB can positively act on the autophagy–lysosome pathway and influence the expression of immunocytokines in DCs.

Hole-transport layer (HTL) plays a crucial role in the photovoltaic performance of perovskite solar cells (PSCs). In order to improve the function property of HTLs, we first use potassium permanganate (KMnO4) as a dopant for the oxidization of 2,2′,7,7′-tetrakis(N,N-p-dimethoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD). The reaction between KMnO4 and spiro-OMeTAD produces the oxidized-state spiro-OMeTAD, which enhances the conductivity and adjusts the energy level of HTL. The dual functions of KMnO4 dopant bring high photovoltaic performance of the devices. The planar PSC based on photoactive layer of mixed-cation–anion perovskite and hole-transport layer of spiro-OMeTAD doped with 1.0 mol % KMnO4 achieves a power conversion efficiency of 20.03%. Meanwhile, the hysteresis effect of the device is greatly suppressed. The simple and low-cost processing and significant performance improvement render this method promising.

The quality of the perovskite layer has an important influence on the photovoltaic performance and stability of perovskite solar cells. An appropriate additive can effectively improve the quality of perovskites. In this work, pyrrole is introduced into a cesium-containing triple cation perovskite precursor solution and this strategy is demonstrated to control the crystallinity of perovskite films. The pyrrole ring is hydrophobic, and its nitrogen atom (N) can combine with the lead–iodine (Pb–I) framework by coordinating with Pb ions or pyrrole forms hydrogen bonds with organic cations. XRD patterns and AFM images prove that pyrrole significantly affects the crystallinity and roughness of perovskite films. The pyrrole-modified device exhibits a champion power conversion efficiency of 20.07%, while the pristine device has an efficiency of 18.58% under the same conditions. This approach suggests an important direction for improving the film quality to reduce trap density and charge recombination.

Tyrosine (Tyr) is crucial to the maintenance of the monoclonal antibody (mAb) titers and quality attributes in fed-batch cultures of recombinant Chinese hamster ovary (rCHO) cells. However, the relation between tyrosine and these aspects is not yet fully defined. In order to further elucidate such a relation, two groups of fed-batch experiments with high tyrosine (H-T) or low tyrosine (L-T) additions producing an IgG1 monoclonal antibody against CD20 were implemented to investigate the intracellular and extracellular effects of tyrosine on the culture performance. It was found that the scarcity of tyrosine led to the distinctive reduction in both viable cell density and antibody specific production rate, hence the sharply reduced titer, possibly related to the impaired translation efficiency caused by the substrate limitation of tyrosine. In addition, alterations to the critical quality attributes were detected in the L-T group, compared to those in the H-T condition. Notable decrease in the contents of intact antibody was found under the L-T condition because of the elevated reductive level in the supernatant. Moreover, the aggregate content in the L-T condition was also reduced, probably resulting from the accumulation of extracellular cystine. In particular, the lysine variant content noticeably increased with tyrosine limitation owing to the downregulation of two carboxypeptidases, i.e., CpB and CpH. Overall, understanding the role of tyrosine in these aspects is fundamental to the increase of product titers and control of critical quality attributes in the monoclonal antibody production of rCHO cell fed-batch cultures. KEY POINTS: • Tyrosine is essential in the maintenance of product titers and the control of product qualities in high cell density cultivations in rCHO cell. • This study revealed the bottleneck of decreased qmAbupon the deficiency of tyrosine. • The impact of tyrosine on the critical product qualities and the underlying mechanisms were also thoroughly assessed.

Interfacial engineering is an efficient strategy for enhancing the performance of perovskite photovoltaic cells. Here, we present a novel method to modify the surface of TiO2 with thiourea. X-ray photoelectron spectroscopy indicates that thiourea treatment inactivates the TiO2 surface groups. Kelvin probe force microscopy and ultraviolet photoelectron spectra demonstrate an energy level downshift of the modified TiO2. Photoluminescence spectra reveal the reduced interface charge recombination and an improved charge transportation/extraction. Tafel and Nyquist plots elucidate a decrease of trap-state density and an increase of conductivity of the modified TiO2. Hence, the planar perovskite solar cell based on the TiO2 electron transport layer (ETL) modified with 0.1 M thiourea yields an efficiency of 19.18%, which is 7.5% larger than that of the device based on the pristine TiO2 ETL. The simple procedure and the significant performance improvement render this method promising.

Lead amine halide perovskite solar cells have been dominating photovoltaic research in this decade. The quality of the perovskite layer plays a significant role in the photovoltaic performance of planar perovskite devices, and solvent engineering is an effective method to improve the quality of the perovskite layer. Here, we introduce acetonitrile (ACN) as an effective solvent additive in the preparation of cation-anion-mixed perovskite of Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3. The morphology observation indicates that a large grain, compact and pinhole-free perovskite layer is obtained by ACN adding. Steady-state and time-resolved photoluminescence measurements demonstrate fewer defects and less carrier recombination in the perovskite layer with ACN adding. The planar perovskite solar cell with ACN adding achieves a power conversion efficiency of 19.15% with slight hysteresis and stable output, while the device without ACN adding gets an efficiency of 17.47% under the same experiment conditions. The simple and green preparation process and the significant improvement of the device performance render this method promising.

Sialic acid content generally affects many biochemical properties of therapeutic glycoproteins. More specific properties, such as charge distribution, circulating half-life and bioactivity, are directly impacted by sialic acid content. Undesirable loss of protein sialylation is commonly observed in CHO bioprocesses, and sialic acid degradation is one of the root causes. In this work, sialic acid degradation by extracellular sialidase was investigated in an Fc-fusion protein production bioprocess. First, cell-free incubation with the cell culture supernatant (CCS) collected at the end of culture revealed a 12.46% drop in sialic acid content by sialidase after 6 days of incubation, while other monosaccharides on the glycans remained stable. Then, potential factors that could affect the action of sialidase were studied, and a pH of over 7.05 was found to have a strong inhibitory effect on the degradation of sialic acid in the CCS. The results were further validated in bioreactors with different pH controls to demonstrate that a minimization of sialic acid loss could be achieved by controlling pH at higher values. Our work provides a simple and effective way to alleviate the decrease in sialic acid content and improves the understanding of the relationship between process control and product sialylation in CHO bioprocesses.

Organic-inorganic hybrid perovskite solar cells have become dominant topics on photovoltaic field in the past decade. The quality of the perovskite layer plays a crucial role in the photovoltaic performance of perovskite devices, and the solvent engineering is an attractive method for improving the quality of perovskite layer. Here, we introduce pyridine additive in the precursor mixed solution to prepare high quality cation-anion-mixed perovskite of Cs0.05 (MA0.17FA0.83)0.95Pb(I0·83Br0.17)3. The morphology observation indicates that a large grain, dense and pinhole-free perovskite film is obtained by pyridine adding. Photoluminescence and resistance measurements demonstrate that pyridine adding contribution to less defects and charge carrier recombination in the perovskite layer. The perovskite solar cell with pyridine adding achieves a power conversion efficiency of 19.03%, while the device without pyridine adding reaches an efficiency of 16.94% at the same experiment conditions. The simple and green procedure and significant improvement in the performance render this method promising.

Lead amine halide perovskite solar cells (PSCs) have become dominant photovoltaic research topic in this decade. Electron transport layer (ETL) play a crucial role on PSCs. Here, we use tin tetrachloride as Sn source to synthesize SnO2 nanocrystals in a simple hydrothermal method. The as-synthesized SnO2 is spin-coated on FTO substrate, and then sintered under low temperature to form the ETL of planar PSCs. The concentration of SnO2 spin-coating solution and sintering temperature have great influence on the ETL quality and charge transportation in PSCs. Through optimized treatment (0.15 M SnO2, 120 °C sintering), the high quality SnO2 ETL with a uniform coverage, appropriate thickness, less charge recombination and low resistance can be obtained. Based on the ETL, a planar PSC with FAxMA1−xPbI3 achieves a high power conversion efficiency (PCE) of 19.34%. In addition, the planar PSCs based on SnO2 exhibit a stable PCE output and slight hysteresis. These researches provide a low-cost, easy strategy to fabricate tin oxide, and present potential to replace traditional titanium oxide (TiO2) in PSCs in the future.

The electron transport layer (ETL) is one of the most important factors to determine the photovoltage (PV) performance of perovskite solar cells (PSCs), and defects and non-radiative recombination are the negative factors limiting the efficiency improvement of PSCs. Herein, using tin oxide (SnO2) as the electron transport layer and multiple functional groups organic molecule of 3-(formamidinothio)-1-propanesulfonic acid (FTPS) as additive of SnO2, we fabricated a high-effective SnO2-based planar PSC. The introduction of FTPS reduces the oxygen vacancy defects of SnO2 ETLs and accommodates perovskite crystal growth on it. The modification of FTPS improves the conductivity and the electron extraction ability of SnO2, mitigates the trap-state density and carrier non-radiative recombination at the interfaces of SnO2/perovskite. As a result, the PSC based on pristine SnO2 ETL obtains a power conversion efficiency (PCE) of 20.49%, while the champion device based on SnO2 + FTPS (0.3 mg/mL) ETL achieves an efficiency of 22.52% with insignificant hysteresis effect and excellent stability. This effective defect passivation strategy work provides a promising low-cost technology for the preparation of planar PSCs with high efficiency and stability.

As the composition of animal cell culture medium becomes more complex, the identification of key variables is important for simplifying and guiding the subsequent medium optimization. However, the traditional experimental design methods are impractical and limited in their ability to explore such large feature spaces. Therefore, in this work, we developed a NRGK (nonparametric regression with Gaussian kernel) method, which aimed to identify the critical components that affect product titres during the development of cell culture media. With this nonparametric model, we successfully identified the important components that were neglected by the conventional PLS (partial least squares regression) method. The superiority of the NRGK method was further verified by ANOVA (analysis of variance). Additionally, it was proven that the selection accuracy was increased with the NRGK method because of its ability to model both the nonlinear and linear relationships between the medium components and titres. The application of this NRGK method provides new perspectives for the more precise identification of the critical components that further enable the optimization of media in a shorter timeframe.

As one kind of promising next-generation photovoltaic devices, perovskite solar cells (PVSCs) have experienced unprecedented rapid growth in device performance over the past few years. However, the practical applications of PVSCs require much improved device long-term stability and performance, and internal defects and external humidity sensitivity are two key limitation need to be overcome. Here, gadolinium fluoride (GdF3 ) is added into perovskite precursor as a redox shuttle and growth-assist; meanwhile, aminobutanol vapor is used for Ostwald ripening in the formation of the perovskite layer. Consequently, a high-quality perovskite film with large grain size and few grain boundaries is obtained, resulting in the reduction of trap state density and carrier recombination. As a result, a power conversion efficiency of 21.21% is achieved with superior stability and negligible hysteresis.

Charge variants, especially acidic charge variants, in recombinant monoclonal antibodies are critical quality attributes, which can affect antibodies' properties in vitro and in vivo. Meanwhile, charge variants are cumulative effects of various post-translational modifications and chemical degradations on antibody. In this work, to investigate the effect of lowering culture pH in the stationary phase on acidic charge variant contents in fed-batch cultures and its mechanism, cell culture experiments in 2-L bioreactors were firstly performed to explore the changes in the charge distribution under the pH downshift condition using weak cation exchange chromatography. It is found that acidic charge variant contents were significantly decreased by pH downshift. Then, to reveal the mechanism by which the content of acidic charge variants is reduced under pH downshift condition, the variation of post-translational modifications and chemical degradations under the pH downshift condition was explored. Meanwhile, the structure of the acidic charge variants was characterized. Several analysis experiments including size exclusion chromatography, capillary electrophoresis-sodium dodecyl sulfate under non-reducing conditions, tryptic peptide map, and reduced antibody mass were applied in this study. The results show that the mechanism by which the content of acidic charge variants is reduced is that the contents of disulfide bond reduction, galactosylation, and asparagine deamination of the HC-N388 in the Fc domain were reduced by pH downshift.

The preparation of high-quality perovskite thin films with low grain boundaries and defect states plays an important role in determining the photovoltaic performance and stability of perovskite solar cells (PSCs). It has been proved that the inorganic CsPbBr3 perovskite material has unique stability. However, the wide band gap and small light absorption range limit the power conversion efficiency (PCE) of the corresponding devices. Here, we report that the addition of guanidine iodide (GAI) into CsPbBr3 precursor solution can greatly improve the quality of CsPbBr3 film, leading to inhibition of interfacial recombination, promotion of charge migration and reduction of trap state density. Ultimately, the planar PSC with GAI modified CsPbBr3 film yields a champion efficiency of 8.54%, much higher than the control one (6.56%).

The ionic nature of the perovskite material results in a great number of defects in the perovskite film which limits the efficiency and stability of perovskite solar cells. The passivation of the defects can effectively suppress the non-radiative recombination of carriers and improve the photovoltaic performance and stability of perovskite solar cells. In this paper, quinoline is introduced into the perovskite precursor solution. By adjusting the addition amount, it is found that quinoline can effectively induce the growth and orientation of perovskite crystals, consequently, improving the film quality and reduce defect density. The optimized device shows higher VOC (1.142 V) and FF (0.792), and achieved a champion power conversion efficiency of 20.87%. In addition, the hysteresis of the device is suppressed and the stability is improved. The results demonstrate that quinoline is an effective perovskite additive.

Hole transport materials (HTMs) play an important role in perovskite solar cells (PSCs). At present, the most frequent used HTM is spiro-OMeTAD. However, spiro-OMeTAD without dopants have low electrical conductivity and hole mobility. Therefore, the improvement of mobility and conductivity of hole transport layer (HTL) has become a crucial issue. Here, we introduce a dopant, thionyl chloride (SOCl2), to oxidize spiro-OMeTAD and generate more spiro-OMeTAD+. Under the same conditions, the optimized device doped with SOCl2 achieves a power conversion efficiency (PCE) of 20.76%, while the pristine one is only 18.13%. The doping of SOCl2 not only reduces the density of defect states at the interface between perovskite and HTL, but also suppresses the recombination of light-induced carriers. In addition, the stability of the PSCs based on SOCl2 is greatly improved, which can maintain 90% of the initial PCE for 31 days under ambient conditions. This work provides a simple and feasible strategy for dopant engineering of HTL to achieve efficient PSCs.