Multi-heterojunctioned plastics with high thermoelectric figure of merit.

Conjugated polymers promise inherently flexible and low-cost thermoelectrics for powering the Internet of Things from waste heat1,2. Their valuable applications, however, have been hitherto hindered by the low dimensionless figure of merit (ZT)3-6. Here we report high-ZT thermoelectric plastics, which were achieved by creating a polymeric multi-heterojunction with periodic dual-heterojunction features, where each period is composed of two polymers with a sub-ten-nanometre layered heterojunction structure and an interpenetrating bulk-heterojunction interface. This geometry produces significantly enhanced interfacial phonon-like scattering while maintaining efficient charge transport. We observed a significant suppression of thermal conductivity by over 60 per cent and an enhanced power factor when compared with individual polymers, resulting in a ZT of up to 1.28 at 368 kelvin. This polymeric thermoelectric performance surpasses that of commercial thermoelectric materials and existing flexible thermoelectric candidates. Importantly, we demonstrated the compatibility of the polymeric multi-heterojunction structure with solution coating techniques for satisfying the demand for large-area plastic thermoelectrics, which paves the way for polymeric multi-heterojunctions towards cost-effective wearable thermoelectric technologies.

The correlation between lung ultrasound scores and outcomes of high-flow nasal cannula therapy in infants with severe pneumonia.

OBJECTIVE: The study aimed to explore the effectiveness of bedside lung ultrasound (LUS) combined with the PaO2/FiO2 (P/F) ratio in evaluating the outcomes of high-flow nasal cannula (HFNC) therapy in infants with severe pneumonia. METHODS: This retrospective study analyzed the clinical data of 150 infants diagnosed with severe pneumonia and treated with HFNC therapy at our hospital from January 2021 to December 2021. These patients were divided into two groups based on their treatment outcomes: the HFNC success group (n = 112) and the HFNC failure group (n = 38). LUS was utilized to evaluate the patients' lung conditions, and blood gas results were recorded for both groups upon admission and after 12 h of HFNC therapy. RESULTS: At admission, no significant differences were observed between the two groups in terms of age, gender, respiratory rate, partial pressure of oxygen, and partial pressure of carbon dioxide. However, the P/F ratios at admission and after 12 h of HFNC therapy were significantly lower in the HFNC failure group (193.08 ± 49.14, 228.63 ± 80.17, respectively) compared to the HFNC success group (248.51 ± 64.44, 288.93 ± 57.17, respectively) (p < 0.05). Likewise, LUS scores at admission and after 12 h were significantly higher in the failure group (18.42 ± 5.3, 18.03 ± 5.36, respectively) than in the success group (15.09 ± 4.66, 10.71 ± 3.78, respectively) (p < 0.05). Notably, in the success group, both P/F ratios and LUS scores showed significant improvement after 12 h of HFNC therapy, a trend not observed in the failure group. Multivariate regression analysis indicated that lower P/F ratios and higher LUS scores at admission and after 12 h were predictive of a greater risk of HFNC failure. ROC analysis demonstrated that an LUS score > 20.5 at admission predicted HFNC therapy failure with an AUC of 0.695, a sensitivity of 44.7%, and a specificity of 91.1%. A LUS score > 15.5 after 12 h of HFNC therapy had an AUC of 0.874, with 65.8% sensitivity and 89.3% specificity. An admission P/F ratio < 225.5 predicted HFNC therapy failure with an AUC of 0.739, 60.7% sensitivity, and 71.1% specificity, while a P/F ratio < 256.5 after 12 h of HFNC therapy had an AUC of 0.811, 74.1% sensitivity, and 73.7% specificity. CONCLUSION: Decreased LUS scores and increased P/F ratio demonstrate a strong correlation with successful HFNC treatment outcomes in infants with severe pneumonia. These findings may provide valuable support for clinicians in managing such cases.

Iminyl-Radical-Mediated Formation of Covalent Au-N Bonds for Molecular Junctions.

The interaction between organic radicals and transition metals plays a crucial role in radical-mediated chemical reactions, functional devices, and biocatalysis. Characterizing such interactions, however, remains a long-standing challenge due to the inherently high reactivity of radical species. Here, using a scanning tunneling microscope breaking junction (STM-BJ) technique, we are able to detect the interaction mode between iminyl radicals and the gold surface at a single molecule level. We show that the free iminyl radicals generated through photochemical N-O bond homolysis of oxime esters react toward the gold electrode surface and produce covalent Au-N bonds. Intriguingly, we find that the Au-N bonding reactions lead to the formation of robust and highly conductive single-molecule junctions. These findings provide not only insights into the mechanism of iminyl-radical-involved reactions but also a facile photolysis method to create a new type of covalent electrode-molecule bonding contact for molecular devices.

Boosting the Thermoelectric Performance of the Doped DPP-EDOT Conjugated Polymer by Incorporating an Ionic Additive.

The thermoelectric (TE) performance of organic materials is limited by the coupling of Seebeck coefficient and electrical conductivity. Herein a new strategy is reported to boost the Seebeck coefficient of conjugated polymer without significantly reducing the electrical conductivity by incorporation of an ionic additive DPPNMe3 Br. The doped polymer PDPP-EDOT thin film exhibits high electrical conductivity up to 1377 ± 109 S cm-1 but low Seebeck coefficient below 30 µV K-1 and a maximum power factor of 59 ± 10 µW m-1 K-2 . Interestingly, incorporation of small amount (at a molar ratio of 1:30) of DPPNMe3 Br into PDPP-EDOT results in the significant enhancement of Seebeck coefficient along with the slight decrease of electrical conductivity after doping. Consequently, the power factor (PF) is boosted to 571 ± 38 µW m-1 K-2 and ZT reaches 0.28 ± 0.02 at 130 °C, which is among the highest for the reported organic TE materials. Based on the theoretical calculation, it is assumed that the enhancement of TE performance for the doped PDPP-EDOT by DPPNMe3 Br is mainly attributed to the increase of energetic disorder for PDPP-EDOT.

A microRNA sponge, LINC02193, promotes neutrophil activation by upregulating ICAM1 and is correlated with ANCA-associated vasculitis.

OBJECTIVE: To investigate the pathogenic role and underlying mechanisms of lncRNAs in antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). METHODS：: RNA-sequencing (RNA-seq) was applied to screen the expression profile of lncRNAs in peripheral leukocytes from 5 AAV patients and 5 healthy controls (HC). Candidate lncRNAs were preliminarily verified in peripheral leukocytes from 46 AAV patients and 35 HC by qRT-PCR. Then, the identified LINC02193 was further validated in peripheral neutrophils from 67 AAV patients, 45 HC and 64 disease controls. Correlation between LINC02193 levels and disease activity was analyzed. Then, a loss-of-function study was conducted to investigate the role of LINC02193 in neutrophils activation. Furthermore, bioinformatics analysis, dual luciferase reporter and RNA immunoprecipitation (RIP) assays were performed to explore the mechanism of LINC02193 regulating neutrophils activation. RESULTS: A total of 467 upregulated and 412 downregulated lncRNAs were identified in AAV patients. From top 5 upregulated lncRNAs, an elevation of LINC02193 was validated in a larger sample of AAV patients, and positively correlated with disease activity. Knockdown of LINC02193 inhibited ROS and NO production, NETs release and adhesion to endothelial cells of differentiated human promyelocytic leukaemia HL­60 cells (dHL-60), whereas overexpression of ICAM1 counteracted these effects. Mechanistic analysis demonstrated that LINC02193 acted as a miR-485-5p sponge to relieve the repressive effect of miR-485-5p on ICAM1, thus promoting ICAM1 expression. CONCLUSION: LINC02193, a novel lncRNA identified in AAV could function as competing endogenous RNAs (ceRNA) for miR-485-5p to promote ICAM1 expression and neutrophils activation, suggesting its potential as a therapeutic target of AAV.

PET vascular activity score for predicting new angiographic lesions in patients with Takayasu arteritis: a Chinese cohort study.

OBJECTIVE: To investigate the ability of 18F-fluorodeoxyglucose PET/CT to predict new lesions in Takayasu arteritis. METHODS: Eighty-two Chinese patients with newly diagnosed Takayasu arteritis were recruited. Their clinical characteristics, serum biomarkers and imaging results were recorded at baseline and every visit. They were followed up for at least 2 years. New angiographic lesions were evaluated by magnetic resonance angiography. Baseline PET vascular activity scores (PETVAS) for predicting new lesions were evaluated. RESULTS: At baseline, a moderate correlation was observed between PETVAS and ESR (r = 0.74, P < 0.01) and CRP level (r = 0.69, P < 0.01). Overall, 18 (22%) patients showed new lesions on imaging during a median follow-up time of 36 months. The median time to the first occurrence of new lesions was 18 months. Compared with patients without new lesions, the patients with new lesions included more female patients (67.2% vs 94.4%, P = 0.03), patients with higher ESR values (20 vs 49, P = 0.02) and patients with active disease (62.5% vs 94.4%, P < 0.01). Multivariate Cox regression analysis revealed PETVAS was an independent risk factor for new angiographic lesions (PETVAS ≥8, hazard ratio = 7.56; 95% CI 2.20, 26.01, P < 0.01) with adjustment of age, sex, chest pain, ESR and Physician Global Assessment. Furthermore, patients with PETVAS ≥8 at baseline were more likely to experience adverse events including arterial ischaemic events during the follow-up. CONCLUSION: PETVAS showed good performance in predicting new lesions in Takayasu arteritis.

Effect of wet-heparinized suction on the quality of mediastinal solid tumor specimens obtained by endoscopic ultrasound-guided fine-needle aspiration: a retrospective study from a single center.

BACKGROUND: Mediastinal lesions are diagnosed sometimes by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Wet-heparinized suction technique has been used to improve the quality of abdominal solid tumor samples obtained by EUS-FNA. The aim of the study is to assess the effect of wet-heparinized suction on the quality of mediastinal solid tumor samples and to evaluate the safety of the method. METHODS: The medical records, EUS-FNA records, pathologic data, and follow-up data between the patients who suspected mediastinal lesions with wet-heparinized suction and conventional suction were retrospectively and comparatively analyzed. Adverse events at 48 h and 1 week after EUS-FNA were evaluated. RESULTS: Wet-heparinized suction contributed to more tissue specimens (P < 0.05), superior tissue integrity (P < 0.05), and a longer length of white tissue core (P < 0.05). In addition, the more complete the tissue bar was, the higher the rate of successful sample (P < 0.05). Moreover, the total length of the white tissue bar at the first puncture was remarkably longer in the Experimental group (P < 0.05). No significant difference in red blood cell contamination in paraffin sections was found between the two groups (P > 0.05). There was no complication after discharge in both groups. CONCLUSION: Wet-heparinized suction can improve the quality of mediastinal lesion samples obtained by EUS-FNA and increase the success rate of sampling. In addition, it will not aggravate blood contamination in paraffin sections while ensuring a safe puncture.

Comparative Analysis of High-Flow Nasal Cannula Oxygen Therapy and Invasive Mechanical Ventilation in the Management of Severe Pneumonia: A Retrospective Study.

Background: Severe pneumonia continues to be a prominent cause of hospitalization and global mortality. There is ongoing debate regarding the effectiveness of different oxygen therapy modalities, particularly high-flow nasal cannula (HFNC) oxygen therapy and invasive mechanical ventilation (IMV), in the treatment of severe pneumonia. Objective: This study investigated the risk factors associated with mechanical ventilation in pediatric patients with severe pneumonia. Methods: This retrospective study included a cohort of 240 pediatric patients with severe pneumonia treated at Zhangzhou Hospital, affiliated with Fujian Medical University, from January 2019 to December 2020. Patients were categorized into two groups: the HFNC group and the IMV group. Comparative analysis was performed on general patient information, infection markers, arterial blood gas values, as well as the prevalence of underlying conditions and complications between the two groups. Multivariate logistic regression analysis was employed to identify the risk factors for invasive mechanical ventilation in children with severe pneumonia. Results: Patients in the HFNC group experienced shorter hospitalization durations, and the average age in this group was lower compared to the IMV group (P < .05). Upon admission, respiratory rate and heart rate were higher in the HFNC group compared to the IMV group (P < .05). The IMV group demonstrated higher oxygenation index (OI) and infection markers, while the pH level was lower in the IMV group than in the HFNC group (P < .05). The prevalence of underlying conditions and complications in the IMV group was significantly higher than in the HFNC group (P < .05). Basic conditions such as heart disease, prematurity, heart failure, low OI, toxic encephalopathy, and influenza virus infection were identified as risk factors for IMV. Conclusions: High-flow nasal cannula therapy has shown therapeutic efficacy in pediatric patients with severe pneumonia. However, children with underlying medical conditions may require prompt tracheal intubation and invasive mechanical ventilation.

Single-Cell RNA-Sequencing Reveals Peripheral T Helper Cells Promoting the Development of IgG4-Related Disease by Enhancing B Cell Activation and Differentiation.

Abnormal B cell differentiation plays a critical role in IgG4-related disease (IgG4-RD), but the underlying mechanism remains largely unknown. We investigated the cell landscape from three IgG4-RD retroperitoneal tissues and three control tissues using single-cell RNA-sequencing. Critical cell type or markers were further validated in the peripheral blood from the patients with IgG4-RD and healthy controls via flow cytometry as well as in the IgG4-RD and control tissue via immunofluorescence staining. The increases in B cells, plasma cells, and CD4+ T cells were found in IgG4-RD retroperitoneal tissue. Importantly, among CD4+ T cells, an increase in CD4+CXCR5-PD1hi peripheral T helper (Tph) cells with a high expression of IL-21 and TIGIT was discovered in IgG4-RD tissue, which was further validated in peripheral blood of the patients with IgG4-RD. The Tph cell and TIGIT+ Tph cell proportion were remarkably higher in active IgG4-RD patients and correlated with disease activity. Moreover, TIGIT+CD4+ cells were able to promote B cell differentiation via IL-21. Our study revealed that Tph cells are increased in IgG4-RD and probably play critical roles in B cell differentiation through TIGIT-IL-21 axis. Peripheral Tph cell and TIGIT+Tph cell are potential markers for IgG4-RD disease activity.

Treatment efficacy and safety of tofacitinib versus methotrexate in Takayasu arteritis: a prospective observational study.

OBJECTIVE: To compare the treatment efficacy and safety of tofacitinib (TOF) versus methotrexate (MTX) in Takayasu arteritis (TAK). METHODS: Fifty-three patients with active disease from an ongoing prospective TAK cohort in China were included in this study. Twenty-seven patients were treated with glucocorticoids (GCs) and TOF, and 26 patients were treated with GCs with MTX. The observation period was 12 months. Complete remission (CR), inflammatory parameter changes, GCs tapering and safety were assessed at the 6th, 9th and 12th month. Vascular lesions were evaluated at the 6th and 12th month, and relapse was analysed during 12 months. RESULTS: The CR rate was higher in the TOF group than in the MTX group (6 months: 85.19% vs 61.54%, p=0.07; 12 months: 88.46% vs 56.52%, p=0.02). During 12 months' treatment, patients in the TOF group achieved a relatively lower relapse rate (11.54% vs 34.78%, p=0.052) and a longer median relapse-free duration (11.65±0.98 vs 10.48±2.31 months, p=0.03). Average GCs dose at the 3rd, 6th and 12th month was lower in the TOF group than that in the MTX group (p<0.05). A difference was not observed in disease improvement or disease progression on imaging between the two groups (p>0.05). Prevalence of side effects was low in both groups (3.70% vs 15.38%, p=0.19). CONCLUSION: TOF was superior to MTX for CR induction, a tendency to prevent relapse and tapering of the GCs dose in TAK treatment. A good safety profile for TOF was also documented in patients with TAK.

FABP3 overexpression promotes vascular fibrosis in Takayasu's arteritis by enhancing fatty acid oxidation in aorta adventitial fibroblasts.

OBJECTIVE: To identify the role of fatty acid binding protein 3 (FABP3) in vascular fibrosis in Takayasu's arteritis (TAK) and to explore the underlying molecular mechanism. METHODS: The expression of FABP3 and extracellular matrix proteins (ECMs) were detected in aorta tissues from TAK patients (n = 12) and healthy controls (n = 8) by immunohistochemistry. The concentration of serum proteins was determined by ELISA. CCK8 and Ki67 staining were used to measure aorta adventitial fibroblast (AAF) proliferation. Widely targeted lipidomic profiling was used to screen for associated metabolic pathways. Changes in ECMs and fatty acid oxidation (FAO)-related enzymes were determined by RT-qPCR and Western blot. The interactions between FABP3 and these enzymes were explored with a co-immunoprecipitation (Co-IP) assay. RESULTS: The expression of FABP3 was increased in the thickened adventitia of TAK patients and was positively correlated with the serum expression of ECMs. FABP3 knockdown inhibited AAF proliferation and ECM production, whereas FABP3 overexpression enhanced these processes. Further analysis revealed that FABP3 upregulation promoted carnitine palmitoyltransferase 1A and carnitine/acylcarnitine carrier protein (CACT) expression, two key enzymes in FAO, as well as adenosine triphosphate (ATP) levels. FABP3 and CACT were co-localized in the adventitia and bound to each other in AAFs. Etomoxir reversed the enhanced FAO, ATP production, AAF proliferation and ECM production mediated by FABP3 upregulation. Treatment with 60 g/day curcumin granules for 3 months reduced the level of serum FABP3. Curcumin also inhibited vascular fibrosis by reducing FABP3-enhanced FAO in AAFs. CONCLUSION: Elevated FABP3 expression accelerated vascular fibrosis in TAK, which was likely mediated by promoting FAO in AAFs.

Biomass decomposition and heavy metal release from seaweed litter, Gracilaria lemaneiformis, and secondary pollution evaluation.

The seaweed Gracilaria lemaneiformis can bioremediate heavy metals and improve the environmental quality of mariculture zones. However, the seaweed litter that is produced in the growth and harvest processes becomes one of the important bottlenecks and causes secondary pollution that restricts the development of sustainable seaweed cultivation. Seaweeds exist widely in the coastal areas of the world and are cultivated on a large scale in Asia, but their decomposition process is rarely studied. Experiments that compared decaying dry (dead) and fresh (falling and dying) Gracilaria were conducted to quantify the differences in decomposition rates and heavy metal release in different physiological states. The heavy metals in the seawater and sediment were investigated. The litterbag technique under controlled laboratory conditions was used. The results indicated that the decomposition rates (k) and decay times in 50% (t50%) and 95% (t95%) values varied between dry and fresh Gracilaria. Fresh Gracilaria exhibited a weight loss rate of 15%, and the dry weight loss was 44%. The variations in MAIs (accumulation index of metals) and MR (release rate of metals) between the dry and fresh Gracilaria litters differed significantly, which provides evidence that metals are released back into the environment from Gracilaria litters. The contacted sediments could accelerate the heavy metal release from Gracilaria. Based on our estimates obtained from a 45 d experiment, at least 27.5％ of Cd, 16％ of Cu, 60.1％ of Pb, 72.3％ of Zn, 49.4％ of Fe, 38.6％ of Mn, 68.1％ of Cr, and 67.5％ of Ni present in the fresh Gracilaria and 37.4％ of Cd, 46.2％ of Cu, 77.7％ of Pb, 53.7％ of Zn, 42.7％ of Fe, 67.2％ of Mn, 75.1％ of Cr, and 73.5％ of Ni present in the dried Gracilaria were released back into the water when the biomass was left to decay. This study simulates and underscores that Gracilaria has an strong effect on the heavy metal cycles in marine environments and offers a theoretical basis for the development of sustainable seaweed industries in mariculture zones.

One-electron oxidation of TAT-motif triplex DNA and the ensuing Hoogsteen hydrogen-bonding dissociation.

One-electron oxidation of adenine (A) leads initially to the formation of adenine radical cation (A•+). Subsequent deprotonation of A•+ can provoke deoxyribonucleic acid (DNA) damage, which further causes senescence, cancer formation, and even cell death. However, compared with considerable reports on A•+ reactions in free deoxyadenosine (dA) and duplex DNA, studies in non-B-form DNA that play critical biological roles are rare at present. It is thus of vital importance to explore non-B-form DNA, among which the triplex is an emerging topic. Herein, we investigate the deprotonation behavior of A•+ in the TAT triplex with continuous A bases by time-resolved laser flash photolysis. The rate constants for the one-oxidation of triplex 8.4 × 108 M-1 s-1 and A•+ deprotonation 1.3 × 107 s-1 are obtained. The kinetic isotope effect of A•+ deprotonation in the TAT triplex is 1.8, which is characteristic of a direct release of the proton into the solvent similar to free base dA. It is thus elucidated that the A•+ proton bound with the third strand is most likely to be released into the solvent because of the weaker Hoogsteen H-bonding interaction and the presence of the highly mobile hydration waters within the third strand. Additionally, it is confirmed through Fourier transform infrared spectroscopy that the deprotonation of A•+ results in the dissociation of the third strand and disruption of the secondary structure of the triplex. These results provide valuable kinetic data and in-depth mechanistic insights for understanding the adenine oxidative DNA damage in the triplex.

Independent Generation and Time-Resolved Detection of 2'-Deoxyguanosin-N2-yl Radicals.

Guanine radicals are important reactive intermediates in DNA damage. Hydroxyl radical (HO. ) has long been believed to react with 2'-deoxyguanosine (dG) generating 2'-deoxyguanosin-N1-yl radical (dG(N1-H). ) via addition to the nucleobase π-system and subsequent dehydration. This basic tenet was challenged by an alternative mechanism, in which the major reaction of HO. with dG was proposed to involve hydrogen atom abstraction from the N2-amine. The 2'-deoxyguanosin-N2-yl radical (dG(N2-H). ) formed was proposed to rapidly tautomerize to dG(N1-H). . We report the first independent generation of dG(N2-H). in high yield via photolysis of 1. dG(N2-H). is directly observed upon nanosecond laser flash photolysis (LFP) of 1. The absorption spectrum of dG(N2-H). is corroborated by DFT studies, and anti- and syn-dG(N2-H). are resolved for the first time. The LFP experiments showed no evidence for tautomerization of dG(N2-H). to dG(N1-H). within hundreds of microseconds. This observation suggests that the generation of dG(N1-H). via dG(N2-H). following hydrogen atom abstraction from dG is unlikely to be a major pathway when HO. reacts with dG.

Degradation of Cytosine Radical Cations in 2'-Deoxycytidine and in i-Motif DNA: Hydrogen-Bonding Guided Pathways.

Radical cations of nucleobases are key intermediates causing genome mutation, among which cytosine C•+ is of growing importance because the ensuing cytosine oxidation causes GC → AT transversions in DNA replication. Although the chemistry and biology of steady-state C oxidation products have been characterized, time-resolved study of initial degradation pathways of C•+ is still at the preliminary stage. Herein, we choose i-motif, a unique C-quadruplex structure composed of hemiprotonated base pairs C(H)+:C, to examine C•+ degradation in a DNA surrounding without interference of G bases. Comprehensive time-resolved spectroscopy were performed to track C•+ dynamics in i-motif and in free base dC. The competing pathways of deprotonation (1.4 × 107 s-1), tautomerization (8.8 × 104 s-1), and hydration (5.3 × 103 s-1) are differentiated, and their rate constants are determined for the first time, underlining the strong reactivity of C•+. Distinct pathway is observed in i-motif compared with dC, showing the prominent features of C•+ hydration forming C(5OH)• and C(6OH)•. By further experiments of pH-dependence, comparison with single strand, and with Ag+ mediated i-motif, the mechanisms of C•+ degradation in i-motif are disclosed. The hydrogen-bonding within C(H)+:C plays a significant role in guiding the reaction flux, by blocking the tautomerization of C(-H)• and reversing the equilibrium from C(-H)• to C•+. The C radicals in i-motif thus retain more cation character, and are mainly subject to hydration leading to lesion products that can induce disruption of i-motif structure and affect its critical roles in gene-regulation.

Neutral-Eosin-Y-Photocatalyzed Silane Chlorination Using Dichloromethane.

Chlorosilanes are versatile reagents in organic synthesis and material science. A mild pathway is now reported for the quantitative conversion of hydrosilanes to silyl chlorides under visible-light irradiation using neutral eosin Y as a hydrogen-atom-transfer photocatalyst and dichloromethane as a chlorinating agent. Stepwise chlorination of di- and trihydrosilanes was achieved in a highly selective fashion assisted by continuous-flow micro-tubing reactors. The ability to access silyl radicals using photocatalytic Si-H activation promoted by eosin Y offers new perspectives for the synthesis of valuable silicon reagents in a convenient and green manner.

Photoinduced C-I bond homolysis of 5-iodouracil: A singlet predissociation pathway.

5-Iodouracil (5-IU) can be integrated into DNA and acts as a UV sensitive chromophore suitable for probing DNA structure and DNA-protein interactions based on the photochemical reactions of 5-IU. Here, we perform joint studies of time-resolved Fourier transform infrared (TR-FTIR) spectroscopy and ab initio calculations to examine the state-specific photochemical reaction mechanisms of the 5-IU. The fact that uracil (U) is observed in TR-FTIR spectra after 266 nm irradiation of 5-IU in acetonitrile and ascribed to the product of hydrogen abstraction by the uracil-5-yl radical (U·) provides experimental evidence for the C-I bond homolysis of 5-IU. The excited state potential energy curves are calculated with the complete active space second-order perturbation//complete active space self-consistent field method, from which a singlet predissociation mechanism is elucidated. It is shown that the initially populated 1(ππ*) state crosses with the repulsive 1(πσ*) or 1(nIσ*) state, through which 5-IU undergoes dissociation to the fragments of (U·) radical and iodine atom. In addition, the possibility of intersystem crossing (ISC) is evaluated based on the calculated vertical excitation energies. Although a probable ISC from 1(ππ*) state to 3(nOπ*) and then to the lowest triplet 3(ππ*) could occur in principal, there is little possibility for the excited state populations bifurcating to triplet manifold, given that the singlet state predissociation follows repulsive potential and should occur within dozens to hundreds of femtoseconds. Such low population of triplet states means that the contribution of triplet state to photoreactions of 5-IU should be quite minor. These results demonstrate clearly a physical picture of C-I bond homolysis of 5-IU and provide mechanistic illuminations to the interesting applications of 5-IU as photoprobes and in radiotherapy of cancer.

Bacillus thuringiensis subsp. sichuansis strain MC28 produces a novel crystal protein with activity against Culex quinquefasciatus larvae.

The Bacillus thuringiensis subsp. sichuansis MC28 strain produces spherical parasporal crystals during sporulation and exhibits remarkable insecticidal activity against dipteran and lepidopteran pests. We characterized a novel cry gene (cry69Aa1), which was found in the pMC95 plasmid of the MC28 strain. The cry69Aa1 gene was inserted into a shuttle vector (pSTK) and expressed in an acrystalliferous mutant B. thuringiensis HD73⁻. In this transformant, a large number of spherical parasporal crystals, which were toxic to Culex quinquefasciatus (Diptera), were formed.

Biomimetic nanocluster photoreceptors for adaptative circular polarization vision.

Nanoclusters with atomically precise structures and discrete energy levels are considered as nanoscale semiconductors for artificial intelligence. However, nanocluster electronic engineering and optoelectronic behavior have remained obscure and unexplored. Hence, we create nanocluster photoreceptors inspired by mantis shrimp visual systems to satisfy the needs of compact but multi-task vision hardware and explore the photo-induced electronic transport. Wafer-scale arrayed photoreceptors are constructed by a nanocluster-conjugated molecule heterostructure. Nanoclusters perform as an in-sensor charge reservoir to tune the conductance levels of artificial photoreceptors by a light valve mechanism. A ligand-assisted charge transfer process takes place at nanocluster interface and it features an integration of spectral-dependent visual adaptation and circular polarization recognition. This approach is further employed for developing concisely structured, multi-task, and compact artificial visual systems and provides valuable guidelines for nanocluster neuromorphic devices.

Nanoscale doping of polymeric semiconductors with confined electrochemical ion implantation.

Nanoresolved doping of polymeric semiconductors can overcome scaling limitations to create highly integrated flexible electronics, but remains a fundamental challenge due to isotropic diffusion of the dopants. Here we report a general methodology for achieving nanoscale ion-implantation-like electrochemical doping of polymeric semiconductors. This approach involves confining counterion electromigration within a glassy electrolyte composed of room-temperature ionic liquids and high-glass-transition-temperature insulating polymers. By precisely adjusting the electrolyte glass transition temperature (Tg) and the operating temperature (T), we create a highly localized electric field distribution and achieve anisotropic ion migration that is nearly vertical to the nanotip electrodes. The confined doping produces an excellent resolution of 56 nm with a lateral-extended doping length down to as little as 9.3 nm. We reveal a universal exponential dependence of the doping resolution on the temperature difference (Tg - T) that can be used to depict the doping resolution for almost infinite polymeric semiconductors. Moreover, we demonstrate its implications in a range of polymer electronic devices, including a 200% performance-enhanced organic transistor and a lateral p-n diode with seamless junction widths of <100 nm. Combined with a further demonstration in the scalability of the nanoscale doping, this concept may open up new opportunities for polymer-based nanoelectronics.