Synthesis of Multifunctional Organic Molecules via Michael Addition Reaction to Manage Perovskite Crystallization and Defect.

Additive engineering plays a pivotal role in achieving high-quality light-absorbing layers for high-performance and stable perovskite solar cells (PSCs). Various functional groups within the additives exert distinct regulatory effects on the perovskite layer. However, few additive molecules can synergistically fulfill the dual functions of regulating crystallization and passivating defects. Here, we custom-synthesized 2-ureido-4-pyrimidone (UPy) organic small molecules with diverse functional groups as additives to modulate crystallization and defects in perovskite films via the Michael addition reaction. Theoretical and experimental investigations demonstrate that the -OH groups in UPy exhibit significant effects in fixing uncoordinated Pb2+ ions, passivation of lead-iodide antisite defects, alleviating hysteresis, and reducing non-radiative recombination. Furthermore, the enhanced C=O and -NH2 motifs interact with the A-site cation via hydrogen bonding, which relieves residual strain and adjusts crystal orientation. This strategy effectively controls perovskite crystallization and passivates defects, ultimately enhancing the quality of perovskite films. Consequently, the open-circuit voltage of the UPy-based p-i-n PSCs reaches 1.20 V, and the fill factor surpasses 84%. The champion device delivers a power conversion efficiency of 25.75%. Remarkably, the unencapsulated device maintained 96.9% and 94.5% of its initial efficiency following 3,360 hours of dark storage and 1,866 hours of 1-sun illumination, respectively.

[Cloning, expression and characterization of a lipase gene, lipC24, from Burkholderia sp. ZYB002].

OBJECTIVE: We cloned a lipase gene, lipC24, from Burkholderia sp. ZYB002 and characterized the recombinant lipase LipC24. METHOD: Based on the known genomic DNA sequence from Burkholderia cecapia JK321, we designed a pair of specific primers for the lipC24 gene and then obtained the full length of lipC24 gene. The lipC24 gene fragment enconding the mature peptide LipC24 was then subcloned into expression plasmid, pACYC-Duet-lipB, and expressed in E. coli. The recombinant protein, LipC24, was purified to homogeneity by HisTrap HP chromatography column and HiTrap DEAE FF chromatography column. RESULTS: We expressed the lipC24 gene from Burkholderia sp. ZYB002 in E. coli Origami 2(DE3). Nucleotide sequencing revealed that the lipC24 gene had an open reading frame of 1317 bp, and the deduced amino acid sequence of LipC24 corresponded to 438 amino acid residues, including a conserved -G-X1-S-X2-G- motif. The relative molecular weight of the purified LipC24 was about 45 kDa. The purified LipC24 displayed hydrolysis activity to various 4-nitrophenyl esters and substrate preference for the medium chain length 4-nitrophenyl-esters. The optimal temperature was 40°C and the optimal pH was 7.5. The lipase was stable between pH 7.0 and 8.0 for 24 hours. However, the half-life was only 16 min at 40°C. CONCLUSION: The LipC24 was a 45 kDa protein, a mesotherm and neutral lipase.

Transparent Recombination Layers Design and Rational Characterizations for Efficient Two-Terminal Perovskite-Based Tandem Solar Cells.

Two-terminal (2T) perovskite-based tandem solar cells (TSCs) arouse burgeoning interest in breaking the Shockley-Queisser (S-Q) limit of single-junction solar cells by combining two subcells with different bandgaps. However, the highest certified efficiency of 2T perovskite-based TSCs (33.9%) lags behind the theoretical limit (42-43%). A vital challenge limiting the development of 2T perovskite-based TSCs is the transparent recombination layers/interconnecting layers (RLs) design between two subcells. To improve the performance of 2T perovskite-based TSCs, RLs simultaneously fulfill the optical loss, contact resistance, carrier mobility, stress management, and conformal coverage requirements. In this review, the definition, functions, and requirements of RLs in 2T perovskite-based TSCs are presented. The insightful characterization methods applicable to RLs, which are inspiring for further research on the RLs both in 2T perovskite-based two-junction and multi-junction TSCs, are also highlighted. Finally, the key factors that currently limit the performance enhancement of RLs and the future directions that should be continuously focused on are summarized.

Tailoring component incorporation for homogenized perovskite solar cells.

Deep-level traps at the buried interface of perovskite and energy mismatch problems between the perovskite layer and heterogeneous interfaces restrict the development of ideal homogenized films and efficient perovskite solar cells (PSCs) using the one-step spin-coating method. Here, we strategically employed sparingly soluble germanium iodide as a homogenized bulk in-situ reconstruction inducing material preferentially aggregated at the perovskite buried interface with gradient doping, markedly reducing deep-level traps and withstanding local lattice strain, while minimizing non-radiative recombination losses and enhancing the charge carrier lifetime over 9 µs. Furthermore, this gradient doping assisted in modifying the band diagram at the buried interface into a desirable flattened alignment, substantially mitigating the energy loss of charge carriers within perovskite films and improving the carrier extraction equilibrium. As a result, the optimized device achieved a champion power conversion efficiency of 25.24% with a fill factor of up to 84.65%, and the unencapsulated device also demonstrated excellent light stability and humidity stability. This work provides a straightforward and reliable homogenization strategy of perovskite components for obtaining efficient and stable PSCs.

Large-n quasi-phase-pure two-dimensional halide perovskite: A toolbox from materials to devices.

Despite their excellent environmental stability, low defect density, and high carrier mobility, large-n quasi-two-dimensional halide perovskites (quasi-2DHPs) feature a limited application scope because of the formation of self-assembled multiple quantum wells (QWs) due to the similar thermal stabilities of large-n phases. However, large-n quasi-phase-pure 2DHPs (quasi-PP-2DHPs) can solve this problem perfectly. This review discusses the structures, formation mechanisms, and photoelectronic and physical properties of quasi-PP-2DHPs, summarises the corresponding single crystals, thin films, and heterojunction preparation methods, and presents the related advances. Moreover, we focus on applications of large-n quasi-PP-2DHPs in solar cells, photodetectors, lasers, light-emitting diodes, and field-effect transistors, discuss the challenges and prospects of these emerging photoelectronic materials, and review the potential technological developments in this area.

Efficient and Stable ß-CsPbI3 Solar Cells through Solvent Engineering with Methylamine Acetate Ionic Liquid.

CsPbI3, an all-inorganic perovskite material with suitable band gap and excellent thermal stability, has garnered significant attention for its potential in perovskite solar cells (PSCs). However, CsPbI3 is susceptible to phase changes from photoactive to photoinactive in humid environments. Hence, it is crucial to achieve controllable growth of CsPbI3 perovskite thin films with the desired ß-crystal phase and compact morphology for efficient and stable PSCs. Herein, MAAc was used as a solvent for the CsPbI3 precursor to fabricate ß-CsPbI3 perovskite. An intermediate compound of CsxMA1-xPbIxAc3-x was initially formed in the MAAc solution, and during annealing, the MA+ and Ac- ions were replaced by Cs+ and I- ions, respectively. Furthermore, the incorporation of strong C═O···Pb coordination stabilized the black-phase ß-CsPbI3 and facilitated the growth of crystals with a narrow vertical orientation and large grain size. As a result, the PSCs with an efficiency of 18.9% and improved stability (less than 10% decay after 2000 h of storage in N2 and less than 30% decay after 500 h of storage in humid air without any encapsulation) were achieved.

Unraveling the Role of Chloride in Vertical Growth of Low-Dimensional Ruddlesden-Popper Perovskites for Efficient Perovskite Solar Cells.

Recently, low-dimensional Ruddlesden-Popper (LDRP) perovskite-based solar cells (PSCs) have been extensively studied because of their robust stability. However, because of the poor conductivity of the organic spacer, the charge transport across the spacers in the LDRP perovskite is considerably poor, and thus regulation of the growth orientation of LDRP cells is of primary importance. So far, the key role of organic cations in controlling the growth orientation of LDRP films has been widely studied, but the impact of halogens has not been sufficiently investigated. Herein, we demonstrate the important role of halogens in determining the characteristics of benzylamine (BZA)-based LDRP perovskite films, where different BZAX salts (X = Cl, Br, I) are adopted. Compared to Br and I, Cl is shown to prominently enlarge the grain size, promote the vertical orientation, reduce the trap state density, and prolong the carrier lifetime of LDRP film, and all these merits effectively accelerate the carrier transport within the film. As a result, a PSC device based on BZACl delivers a champion PCE of 17.25% with much improved device stability. This work unravels the vital role of Cl in regulating the crystallization process of LDRP films, which provides a facile approach for boosting the performance of LDRP-based PSCs.

In Situ Interfacial Passivation of Sn-Based Perovskite Films with a Bi-functional Ionic Salt for Enhanced Photovoltaic Performance.

Environment-friendly Tin (Sn)-based perovskite solar cells (PSCs) have lately made significant development, showing tremendous promise in addressing the hazardous problems associated with Pb-based PSCs. However, even in N2 atmospheres, the thermodynamic stability of Sn-based perovskite films and long-term stability of Sn-based PSCs are demonstrated to be poor due to the presence of interfacial defect trap states. Here, we demonstrate the post-treatment of Sn-based perovskite films with ethylenediamine formate (EDAFa2) ion salt, serving as a bi-functional interface layer to in situ passivate the interfacial defect and improve the stability of Sn2+ by creating a thermodynamic chemical environment pathway. Moreover, the presence of EDAFa2 is shown to promote the interfacial energy level alignment, which is beneficial for the charge extraction at the interface. As a result, PSC devices with a bi-functional interface achieve a champion power conversion efficiency (PCE) as high as 9.40% and enhanced stability, retaining ∼95% of the original PCE stored in a N2 environment after ∼1960 h without encapsulation. This work highlights the significant role of an interfacial design in efficient and stable Sn-based PSCs.

Preparation of anionic polyelectrolyte modified magnetic nanoparticles for rapid and efficient separation of lysozyme from egg white.

Poly(sodium 4-styrenesulfonate) modified magnetic nanoparticles (PSS-MNPs) were successfully synthesized and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, vibrating sample magnetometry, and Fourier-transform infrared spectrometry. The PSS-MNPs were found to enable effective separation of lysozyme from egg white. The impacts of solution pH, ionic strength, and contact time on the adsorption process were investigated. The adsorption kinetic data were well fitted using a pseudo-second-order kinetic model and the adsorption equilibrium can be reached in 3 min. The adsorption isotherm data could be well described by the Langmuir equation. The maximum adsorption capacity of PSS-MNPs for lysozyme was calculated to be 476.2 mg g(-1) according to the Langmuir adsorption isotherm. The fast and efficient adsorption of lysozyme by PSS-MNPs was mainly based on electrostatic interactions between them. The adsorbed lysozyme can be eluted using 20mM phosphate buffer (pH 7.0) containing 1.0M NaCl with a recovery of 96%. The extracted lysozyme from egg white demonstrated high purity, retaining about 90.7% of total lysozyme activity.

Cationic polyelectrolyte functionalized magnetic particles assisted highly sensitive pathogens detection in combination with polymerase chain reaction and capillary electrophoresis.

Pathogenic bacteria cause significant morbidity and mortality to humans. There is a pressing need to establish a simple and reliable method to detect them. Herein, we show that magnetic particles (MPs) can be functionalized by poly(diallyl dimethylammonium chloride) (PDDA), and the particles (PDDA-MPs) can be utilized as adsorbents for capture of pathogenic bacteria from aqueous solution based on electrostatic interaction. The as-prepared PDDA-MPs were characterized by Fourier-transform infrared spectroscopy, zeta potential, vibrating sample magnetometry, X-ray diffraction spectrometry, scanning electron microscopy, and transmission electron microscopy. The adsorption equilibrium time can be achieved in 3min. According to the Langmuir adsorption isotherm, the maximum adsorption capacities for E. coli O157:H7 (Gram-negative bacteria) and L. monocytogenes (Gram-positive bacteria) were calculated to be 1.8×10(9) and 3.1×10(9)cfumg(-1), respectively. The bacteria in spiked mineral water (1000mL) can be completely captured when applying 50mg of PDDA-MPs and an adsorption time of 5min. In addition, PDDA-MPs-based magnetic separation method in combination with polymerase chain reaction and capillary electrophoresis allows for rapid detection of 10(1)cfumL(-1) bacteria.

[An experimental study(II) on the inhibition of prostatic hyperplasia by extract of seeds of Brassica alba].

OBJECTIVE: To study the active components and their functionary mechanism of the extract of Brassica alba seeds, which inhibits experimental mice prostatic hyperplasia. METHOD: Prostatic hyperplasia of castrated male mice induced by testosterone propionate, the penetrability of capillary vessel of mice skin induced by histamine and the endermic flesh bud of rat induced by filter paper were used as experimental models. Sinalbin and beta-sitosterol separated from seeds of Brassica alba were used to test the activities. RESULT: Sinalbin and beta-sitosterol(16.0 mg.kg-1.d-1 and 8.0 mg.kg-1.d-1) could significantly inhibit mice prostatic hyperplasia induced by testosterone propionate and activity of serum acid phosphatase(P < 0.01 or P < 0.05), Sinalbin(16.0 mg.kg-1.d-1)could significantly inhibit the hyperplasia of endermic flesh bud in rat induced by filter paper(P < 0.05), beta-sitosterol(16.0 mg.kg-1.d-1 and 8.0 mg.kg-1.d-1) could significantly decrease the penetrability of capillary vessel of mice skin induced by histamine. CONCLUSION: Sinalbin and beta-sitosterol have anti-androgen and anti-inflammation activities.

[An experimental study(I) on the inhibition of prostatic hyperplasia with extract of seeds of Brassica alba].

OBJECTIVE: To study the effective fraction of the extract of seeds of Brassica alba, which inhibits experimental mice prostatic hyperplasia. METHOD: An experimental model of prostatic hyperplasia of castrated male mice induced by testosterone propionate was made. Fractions I, II and III were prepared by extracting the seeds of Brassica alba successively with ether, ethanol and water under reflux. Total extract was prepared by extracting the seeds of Brassica alba with 60% ethanol under reflux. The total extract and the three fractions were used to test the activities. RESULT: Total extract, fractions I and II could not only significantly inhibit mice prostatic hyperplasia induced by testosterone propionate and activity of serum acid phosphatase, but also decrease wet weight of preputial glands, while fraction III is inactive. CONCLUSION: Extract from seeds of Brassica alba can significantly inhibit mice prostatic hyperplasia induced by exterior hormone, possessing an activity of anti-androgen. Fractions I and II show an equivalent activity of total extract, which indicate that these fractions contain active components of seeds of Brassica alba which can inhibit prostatic hyperplasia.

[Laryngotracheal reconstruction in children with subglottic stenosis].

OBJECTIVE: To study the effect of laryngotracheal reconstruction (LTR) in children with subglottic stenosis (SGS), and to discuss the indications and the risks of intraoperative and postoperative treatment of LTR. METHODS: From September 2008 to February 2010, 5 children (4 girls and 1 boy, aged 4 to 6 years) were treated by LTR. Among the 5 children, there were 2 congenital SGS and 3 acquired SGS. One had mild grade III SGS, 3 had severe grade III SGS, and one had grade IV SGS. One child with mild III SGS was treated by single-stage LTR, and the rest four children were treated by double-stage LTR. The surgical technique consisted of cricoid lamina midline vertical incision, rib cartilage graft interposition and endotracheal tube (ETT) stenting for 2 to 3 weeks. RESULTS: Four children with grade III SGS were de-cannulated 3 months after operation, and the child with grade IV SGS got de-cannulated 6 months after operation. Of all children, rib cartilage graft grower well, and the size of subglottis were amplified by grade III SGS to grade I SGS, and grade IV SGS to grade II SGS. All children obtained stable airway. One child with grade IV SGS who had hoarseness got effective phonation during follow-up 2 years after operation. CONCLUSIONS: LTR is a safe and effective treatment for pediatric subglottic stenosis. The important factors of successful operation are correct assessment and evaluation of the severity and overall medical status and selection of suitable surgical techniques.

Lingual thyroglossal duct cyst with recurrence after cystectomy or marsupialization under endoscopy: diagnosis and modified Sistrunk surgery.

OBJECTIVE: To explore the radiologic characteristics of lingual thyroglossal duct cyst relevant to diagnosis. In addition, to probe the feasibility of modified Sistrunk surgery for patients who experience recurrence after cystectomy or marsupialization under endoscopy. STUDY DESIGN: Retrospective. METHODS: Seven patients, three male and four female, who had been diagnosed with lingual thyroglossal duct cysts, had received cystectomy or marsupialization under endoscopy between one and eight times with cyst recurrence soon after every operation. All of these cases were evaluated by CT before proceeding with the latest modified Sistrunk surgery. During surgery, we routinely used methylene blue to trace the cysts, and then we used an enlarged Sistrunk procedure for such cases. RESULTS: The CT images demonstrated that there were cysts located posteriorly to the tongue that had a close relationship with the hyoid bone and the foramen cecum. In addition, the results of the pathological examinations were consistent with thyroglossal duct cysts. During the postoperative follow up of 18 to 31 months, the patients did not show any symptoms or signs of recurrence. The results of their most recent examinations, two by laryngoscopy and five by CT scan, did not reveal any abnormality in their pars laryngea pharyngis. CONCLUSIONS: CT could differentiate lingual thyroglossal duct cysts from the other cysts occurring at the lingual root. For those patients with lingual thyroglossal duct cysts that recur after cystectomy or marsupialization under endoscopy, the modified Sistrunk operation could be a suitable treatment option.

[Construction of Aspergillus niger lipase mutants with oil-water interface independence].

Based on previous bioinformational analysis results, two Aspergillus niger lipase (ANL) mutants, ANL-Ser84Gly and ANL-Asp99Pro were constructed to screen ANL mutants with oil-water interface independence. ANL-Ser84Gly still displayed a pronounced interfacial activation, while ANL-Asp99Pro displayed no interfacial activation. The specific activity of ANL-Ser84Gly towards p-nitrophenyl palmitate (-myristate, -laurate and -decanoate) decreased by 29.8% (53.1, 60.1 and 77.1, respectively) than that of ANL, while the specific activity of ANL-Asp99Pro towards p-nitrophenyl palmitate increased by 2.2-fold. The mutation in the hinge region at both sides of the lid domain also destabilized various secondary structure factors of ANL-S84G and ANL-D99P, which resulted in a substantial decrease in thermostability. The achievement to construct oil-water interface-independent ANL mutants would help to further understand lipase interfacial activation mechanism.

[Expression and purification of recombinant human interleukin 4 in Escherichia coli].

Human interleukin 4 (IL-4) cDNA was optimized and synthesized according to E. coli preferred codon. A recombinant expression plasmid pET-30a (+)/rhIL-4 was constructed with the target cDNA inserted between Nde I and EcoR I sites, which can translate the mature IL-4 protein with an extra methionine residue at N-terminal. The expression vector was transformed into E. coli BL21 (DE3). The rhIL-4 protein was expressed in the inclusion body. By using the optimized fermentation conditions, the high expression level was achieved with the expression level as high as 35% of total protein obtained. A purification strategy has been designed which includes Q-Sepharose and SP-Sepharose ion-exchange chromatography and dialysis renaturation. The rhIL-4 was purified with the purity more than 98% and the yield of 40 mg per liter fermentation culture achieved. Western blot proved that the purified protein is IL-4. Amino acid sequencing revealed that N-terminal 16 residue sequence is identical to the theoretical sequence. Biological activity assay on TF-1 cells demonstrated that the rhIL-4 is active with an activity of 2.5 x 10(6) AU/mg. This study promises large scale production of rhIL-4.