DapF stabilizes the substrate-favoring conformation of RppH to stimulate its RNA-pyrophosphohydrolase activity in Escherichia coli.

mRNA decay is an important strategy by which bacteria can rapidly adapt to their ever-changing surroundings. The 5'-terminus state of mRNA determines the velocity of decay of many types of RNA. In Escherichia coli, RNA pyrophosphohydrolase (RppH) is responsible for the removal of the 5'-terminal triphosphate from hundreds of mRNAs and triggers its rapid degradation by ribonucleases. A diaminopimelate epimerase, DapF, can directly interact with RppH and stimulate its hydrolysis activity in vivo and in vitro. However, the molecular mechanism remains to be elucidated. Here, we determined the complex structure of DapF-RppH as a heterotetramer in a 2:2 molar ratio. DapF-bound RppH exhibits an RNA-favorable conformation similar to the RNA-bound state, suggesting that association with DapF promotes and stabilizes RppH in a conformation that facilitates substrate RNA binding and thus stimulates the activity of RppH. To our knowledge, this is the first published structure of an RNA-pyrophosphohydrolysis complex in bacteria. Our study provides a framework for further investigation of the potential regulators involved in the RNA-pyrophosphohydrolysis process in prokaryotes.

Structural insights into operator recognition by BioQ in the Mycobacterium smegmatis biotin synthesis pathway.

BACKGROUND: Biotin is an essential cofactor in living organisms. The TetR family transcriptional regulator (TFTR) BioQ is the main regulator of biotin synthesis in Mycobacterium smegmatis. BioQ represses the expression of its target genes by binding to a conserved palindromic DNA sequence (the BioQ operator). However, the mechanism by which BioQ recognizes this DNA element has not yet been fully elucidated. METHODS/RESULTS: We solved the crystal structures of the BioQ homodimer in its apo-form and in complex with its specific operator at 2.26 Šand 2.69 Šresolution, respectively. BioQ inserts the N-terminal recognition helix of each protomer into the corresponding major grooves of its operator and stabilizes the formation of the complex via electrostatic interactions and hydrogen bonding to induce conformational changes in both the DNA and BioQ. The DNA interface of BioQ is rich in positively charged residues, which help BioQ stabilize DNA binding. We elucidated the structural basis of DNA recognition by BioQ for the first time and identified the amino acid residues responsible for DNA binding via further site-directed mutagenesis. GENERAL SIGNIFICANCE: Our findings clearly elucidate the mechanism by which BioQ recognizes its operator in the biotin synthesis pathway and reveal the unique structural characteristics of BioQ that are distinct from other TFTR members.

[Comparison of national standard GB/T 31774 and international standard ISO 18668 for Chinese medicines coding system].

Coding rules for Chinese medicines and their codes (GB/T 31774-2015) was issued by General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China (AQSIQ) and Standardization Administration of the People's Republic of China (SAC) in 2015. Coding system for Chinese medicines (ISO 18668-1, 2, 3 and 4) series were issued one after another by International Organization for Standardization in 2016 and 2017. In this paper, the comparative study on the GB/T 31774 and ISO 18668-1, 2, 3 to 4 would be conducted to expound the similarities and differences among them. This essay aims at promoting the application of national and international standards of coding system in production and operation enterprises and the medical institutions of traditional Chinese medicine (TCM), reducing their repetitive investment to meet the Chinese medicine import and export trade requirement in future. Moreover, it provides the cornerstone and support for TCM standardization, and makes Chinese medicines standard gain dominance in field of international TCM standards, occupying the high ground of international market in the traditional medicine field of the world. It may promote the "Internet + TCM service" in our country, and let the Chinese medicine industry go out of the country and into the world to contribute to human health.

Molecular Engineering of Pyrido[3,4-b]pyrazine-Based Donor-Acceptor-π-Acceptor Organic Sensitizers: Effect of Auxiliary Acceptor in Cobalt- and Iodine-Based Electrolytes.

Due to the ease of tuning its redox potential, the cobalt-based redox couple has been extensively applied for highly efficient dye-sensitized solar cells (DSSCs) with extraordinarily high photovoltages. However, a cobalt electrolyte needs particular structural changes in the organic dye components to obtain such high photovoltages. To achieve high device performance, specific requirements in the molecular tailoring of organic sensitizers still need to be met. Besides the need for large electron donors, studies of the auxiliary acceptor segment of donor-acceptor-π-acceptor (D-A-π-A) organic sensitizers are still rare in molecular optimization in the context of cobalt electrolytes. In this work, two novel organic D-A-π-A-type sensitizers (IQ13 and IQ17) have been developed and exploited in cobalt- and iodine-based redox electrolyte DSSCs, specifically to provide insight into the effect of π-bridge modification in different electrolytes. The investigation has been focused on the additional electron-withdrawing acceptor capability with grafted long alkoxy chains. Optoelectronic transient measurements have indicated that IQ17 containing a pyrido[3,4-b]pyrazine moiety bearing long alkoxyphenyl chains is more suitable for application in cobalt-based DSSCs.

The expression levels of transcription factors T-bet, GATA-3, RORγt and FOXP3 in peripheral blood lymphocyte (PBL) of patients with liver cancer and their significance.

OBJECTIVES: To investigate the expression of transcriptional factors (TFs) T-bet, GATA-3, RORγt and FOXP in peripheral blood mononuclear cells (PBMC) of patients with hepatocellular carcinoma (HCC) and to evaluate the correlation between the imbalances of Th1/Th2, Th17/Treg at the expression levels and liver cancer Methods: The peripheral venous blood was drawn from 20 HCC-patients (HCC-group) and 20 health participants (C-group). The expression levels of Th1, Th2 and Th17 and the major Treg-specific TFs T-bet, GATA-3, RORγt and FOXP3 in the PBMC were measured with quantitative real-time PCR(RT-qPCR). RESULTS: The mRNA level of Th1-specific TF T-bet in HCC-group was significantly lower than that of C-group (52.34±34.07 VS 104.01±56.00, P<0.01); the mRNA level of Th2-specifc TF, GATA-3, in HCC group was significantly higher than that in C-group (1.38±1.15 VS 0.58±0.65, P<0.05) and T-bet mRNA/GATA-3 mRNA ratio was significantly lower in HCC-group than in C-group (86.01±116.71 VS 461.88±708.81, P<0.05). The mRNA level of Th17-specific TF RORγt in HCC-group was significantly higher than that of C-group (72.32±32.82 VS 33.07±22.86, P<0.01). Treg-specific TF FOXP3 mRNA level was significant higher in HCC-group than in C-group (3.17±1.59 VS 1.39±1.13, P<0.01) CONCLUSION: T-bet mRNA level was reduced whereas GATA-3 mRNA level was increased and T-bet/GATA-3 ratio was significantly reduced in PBMC, indicating that Th1/Th2 ratio was of imbalance at TF levels in PBMC of HCC, displaying Th2 thrift phenomena. The mRNA levels of RORγt and FOXP3 in PBMC of HCC were significantly increased, indicating the existence of a predominant phenomenon of Th17- and Treg-expressing PBMC in HCC.

Quantitative Evaluation of Female Pattern Hair Loss in Chinese Women: A Preliminary Study.

BACKGROUND: The common grading systems for female pattern hair loss (FPHL), such as Ludwig and Savin scales, are subjective to visual inspection. To provide a more objective evaluation of baldness, the authors have developed a method to calculate baldness quantitatively through a computer-aided imaging system (CAIS). OBJECTIVE: To investigate the use of CAIS on Chinese women with FPHL. MATERIALS AND METHODS: Thirty-eight Chinese women with FPHL (Savin Scale I-2 to II-2) were recruited. A total of 215 photographs were taken. The central balding areas (CBAs) were calculated after exposure correction by CAIS for comparison with clinical staging. RESULTS: The average CBA was 9,391.12 mm in all patients, 3,828.84 mm in Type I-2, 5,880.38 mm in I-3, 8,267.44 mm in I-4, 12,999.26 mm in II-1, and 15,979.71 mm in II-2. The values of CBA correlated with clinical staging using Savin scales. A 7.53% difference was found in the calculated CBA by exposure correction. CONCLUSION: The CAIS allows physicians to evaluate the severity of baldness more accurately through quantitative calculation, rather than qualitative visual observation. The values of the CBA measured by the CAIS, used in conjunction with the present grading systems, may be more precise and efficient to evaluate the severity of FPHL.

Influence of the donor size in D-π-A organic dyes for dye-sensitized solar cells.

We report two new molecularly engineered push-pull dyes, i.e., YA421 and YA422, based on substituted quinoxaline as a π-conjugating linker and bulky-indoline moiety as donor and compared with reported IQ4 dye. Benefitting from increased steric hindrance with the introduction of bis(2,4-dihexyloxy)benzene substitution on the quinoxaline, the electron recombination between redox electrolyte and the TiO2 surface is reduced, especially in redox electrolyte employing Co(II/III) complexes as redox shuttles. It was found that the open circuit photovoltages of IQ4, YA421, and YA422 devices with cobalt-based electrolyte are higher than those with iodide/triiodide electrolyte by 34, 62, and 135 mV, respectively. Moreover, the cells employing graphene nanoplatelets on top of gold spattered film as a counter electrode (CE) show lower charge-transfer resistance compared to platinum as a CE. Consequently, YA422 devices deliver the best power conversion efficiency due to higher fill factor, reaching 10.65% at AM 1.5 simulated sunlight. Electrochemical impedance spectroscopy and transient absorption spectroscopy analysis were performed to understand the electrolyte influence on the device performances with different counter electrode materials and donor structures of donor-π-acceptor dyes. Laser flash photolysis experiments indicate that even though the dye regeneration of YA422 is slower than that of the other two dyes, the slower back electron transfer of YA422 contributes to the higher device performance.

DWT-based segmentation method for coronary arteries.

This work presents a new method for segmenting coronary arteries automatically in computed tomography angiography (CTA) data sets. The method automatically isolates heart and coronary arteries from surrounding structures and search for the probable location of coronary arteries by 3D region growing. Based on the dilation of the probable location, discrete wavelet transformation (DWT) and λ - mean operation complete accurate detection of coronary arties. Finally, the proposed method is tested on clinical CTA data-sets. The results on clinical datasets show that the proposed method is able to extract each branch of arteries when comparing to commercial software GE Healthcare and delineated ground truth.

Prognostic value of human papillomavirus cell-free DNA in cervical cancer patients: A systematic review and meta-analysis.

OBJECTIVE: This meta-analysis aimed to investigate the association between circulating human papillomavirus (HPV) cell-free DNA and oncological outcomes of cervical cancer patients. METHODS: Searches were performed in MEDLINE, Embase, and CENTRAL from their inception until 26 November 2023. Inclusion criteria were: (1) pathologically confirmed cervical cancer with available HPV test results; (2) detection of HPV cell-free DNA was performed in serum/plasma before or at end of treatment; (3) studies reported oncological outcomes of cervical cancer patients according to the levels of HPV cell-free DNA. Data extraction and study quality assessment were performed independently by two authors. Pooled hazard ratios and 95% confidence intervals were calculated using the inverse-variance method for survival outcomes. RESULTS: Five studies were finally included in this meta-analysis. Blood samples were collected from 167 patients before treatment, with 150 individuals available for analysis at the end of treatment. Furthermore, 82 patients with available samples at 3 months post-treatment were included in the analysis. The pooled results indicated a significant association between positive HPV cell-free DNA at end of treatment and worse progression-free survival in patients with cervical cancer (pooled hazard ratio: 5.49; 95 % confidence interval: 2.85-10.58; I2: 0 %). Similar findings were observed in patients with detectable HPV cell-free DNA at 3 months post-treatment (pooled hazard ratio: 7.86; 95 % confidence interval: 3.32-18.60; I2: 0 %). However, the detection of HPV cell-free DNA before treatment was not significantly associated with progression-free survival (pooled hazard ratio: 0.97; 95 % confidence interval: 0.55-1.71; I2: 0 %). CONCLUSION: Cervical cancer patients testing positive for HPV cell-free DNA at the end of treatment or 3 months post-treatment displayed significantly poorer oncological outcomes compared to those testing negative. Thus, personalized monitoring of HPV cell-free DNA holds promise as a prognostic biomarker for patients with cervical cancer.

Survival after minimally invasive radical hysterectomy with protective colpotomy for early-stage cervical cancer: A systematic review and meta-analysis.

Minimally invasive surgery on treatment of early-stage cervical cancer is debatable. Traditional approaches of colpotomy are considered responsible for an inferior oncological outcome. Evidence on whether protective colpotomy could optimize minimally invasive technique and improve prognoses of women with early-stage cervical cancer remains limited. We produced a systematic review and meta-analysis to compare oncological outcomes of the patients treated by minimally invasive radical hysterectomy with protective colpotomy to those treated by open surgery according to existing literature. We explored PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov from inception to December 2022. Inclusion criteria were: (1) randomized controlled trials or observational studies published in English, (2) studies comparing minimally invasive radical hysterectomy with protective colpotomy to abdominal radical hysterectomy in early-stage cervical cancer, and (3) studies comparing survival outcomes. Two reviewers performed the screening, data extraction, and quality assessment independently. A total of 8 retrospective cohort studies with 2020 women were included in the study, 821 of whom were in the minimally invasive surgery group, and 1199 of whom were in the open surgery group. The recurrence-free survival and overall survival in the minimally invasive surgery group were both similar to that in the open surgery group (pooled hazard ratio, 0.88 and 0.78, respectively; 95% confidence interval, 0.56-1.38 and 0.42-1.44, respectively). Minimally invasive radical hysterectomy with protective colpotomy on treatment of early-stage cervical cancer had similar recurrence-free survival and overall survival compared to abdominal radical hysterectomy. Protective colpotomy could be a guaranteed approach to modifying minimally invasive technique.

Effects of combining multiple dose reduction techniques on coronary computed tomography angiography.

BACKGROUND: Coronary computed tomography angiography (CCTA) is the preferred non-invasive examination method for coronary heart disease. However, the radiation from computed tomography has become a concern since public awareness of radiation hazards continue to increase. AIM: To explore the value of multiple dose reduction techniques for CCTA. METHODS: Consecutive normal and overweight patients were prospectively divided into two groups: Group A1, patients who received multiple dose reduction scans (n = 82); and group A2, patients who received conventional scans (n = 39). The scan parameters for group A1 were as follows: Isocentric scan, tube voltage = 80 kV, and tube current control using 80% smart milliampere. The scan parameters for group A2 were as follows: Normal position, tube voltage = 100 kV, and smart milliampere. RESULTS: The average effective doses (EDs) for groups A1 and A2 were 1.13 ± 0.35 and 3.36 ± 1.30 mSv, respectively. There was a statistically significant difference in ED between the two groups (P < 0.01). Furthermore, noise was significantly lower, and both signal-to-noise ratio and contrast signal-to-noise ratio were higher in group A2 when compared to group A1 (P < 0.01). Moreover, the subjective image quality (IQ) scores were excellent in both groups, in which there was no significant difference in subjective IQ score between the two groups (P = 0.12). CONCLUSION: Multiple dose reduction scan techniques can significantly decrease the ED of patients receiving CCTA examinations for clinical diagnosis.

Magnetic Resonance Imaging Features and Misdiagnosis of Spinal Epidural Cavernous Hemangioma.

OBJECTIVE: Spinal epidural cavernous hemangiomas (SECHs) are rare, and merely a few have previously been described in case reports. The present study aims to explore the magnetic resonance imaging (MRI) features of SECHs and analyze the causes of their preoperative misdiagnosis. METHODS: The present retrospective study included 11 patients (three male and eight female patients, mean age ± standard deviation: 47.55±17.39 years old) with histopathologically confirmed SECH between January 2015 and April 2021. The MRI features of SECH were analyzed by two radiologists. RESULTS: The cervical, thoracic and thoracolumbar segments were involved in 2, 7 and 2 patients, respectively. All lesions grew along the long axis of the spine. The tumors were shuttle-shaped in six patients, oval in two patients, pseudopodia-shaped in one patient, clamp-shaped in one patient, and growing outward along the intervertebral foramen in one patient. Nine SECHs had relatively uniform isointense or hypointense T1-weighted imaging (T1WI) and hyperintense T2-weighted imaging (T2WI) signals. On the T2WI, filamentary low-signal shadows (i.e., the hairline or grid sign) with significant contrast enhancement and asymptotic strengthening were observed. Two SECHs had mixed high and low signals on T1WI and T2WI, with significant heterogeneous enhancement, hemorrhage, and hemosiderin deposition. The SECH was misdiagnosed as meningioma, neurofibromatosis and schwannoma in 1, 1 and 4 patients, respectively, while this was not diagnosed in one patient. The preoperative diagnosis was correct in merely approximately 36% of patients. Among the four patients with a correct preoperative diagnosis, hemosiderin deposition was found in three patients and small tortuous vascular shadows were found in one patient. CONCLUSION: SECH presents as a long spindle-shaped mass, and the "'pen cap sign" is common at the lesion edges. SECH also exhibits a hairline or grid sign on T2WI. Furthermore, some lesions present with hemorrhage and hemosiderin deposition. Therefore, the hairline, grid sign and hemosiderin deposition are valuable diagnostic features of SECH.

Constructing organic D-A-π-A-featured sensitizers with a quinoxaline unit for high-efficiency solar cells: the effect of an auxiliary acceptor on the absorption and the energy level alignment.

Four organic D-A-π-A-featured sensitizers (TQ1, TQ2, IQ1, and IQ2) have been studied for high-efficiency dye-sensitized solar cells (DSSCs). We employed an indoline or a triphenylamine unit as the donor, cyanoacetic acid as the acceptor/anchor, and a thiophene moiety as the conjugation bridge. Additionally, an electron-withdrawing quinoxaline unit was incorporated between the donor and the π-conjugation unit. These sensitizers show an additional absorption band covering the broad visible range in solution. The contribution from the incorporated quinoxaline was investigated theoretically by using DFT and time-dependent DFT. The incorporated low-band-gap quinoxaline unit as an auxiliary acceptor has several merits, such as decreasing the band gap, optimizing the energy levels, and realizing a facile structural modification on several positions in the quinoxaline unit. As demonstrated, the observed additional absorption band is favorable to the photon-to-electron conversion because it corresponds to the efficient electron transitions to the LUMO orbital. Electrochemical impedance spectroscopy (EIS) Bode plots reveal that the replacement of a methoxy group with an octyloxy group can increase the injection electron lifetime by a factor of 2.4. IQ2 and TQ2 can perform well without any co-adsorbent, successfully suppress the charge recombination from TiO(2) conduction band to I(3)(-) in the electrolyte, and enhance the electron lifetime, resulting in a decreased dark current and enhanced open circuit voltage (V(oc)) values. By using a liquid electrolyte, DSSCs based on dye IQ2 exhibited a broad incident photon-to-current conversion efficiency (IPCE) action spectrum and high efficiency (η=8.50 %) with a short circuit current density (J(sc)) of 15.65 mA cm(-2), a V(oc) value of 776 mV, a fill factor (FF) of 0.70 under AM 1.5 illumination (100 mW cm(-2)). Moreover, the overall efficiency remained at 97% of the initial value after 1000 h of visible-light soaking.

A Novel Prognostic Model Based on Seven Necroptosis-Related miRNAs for Predicting the Overall Survival of Patients with Lung Adenocarcinoma.

Lung adenocarcinoma (LUAD) remains one of the leading causes of cancer-related deaths worldwide. This study is aimed at constructing a risk scoring model based on necroptosis-related miRNAs to predict prognosis of LUAD. Expression profile of miRNA in LUAD was downloaded from The Cancer Genome Atlas (TCGA) database. We screened the differentially expressed necroptosis-related miRNAs between LUAD patients and normal samples, thus constructed a seven miRNA-based risk stratification on the basis of the TGCA cohort. This risk stratification was prove to be effective in predicting the overall survival (OS) of patients with LUAD. Furthermore, we constructed a nomogram model based on the combination of risk characteristics and clinicopathological features, which was also prove to be accurate and efficient in predicting OS of LUAD patients. Functional enrichment analyses on the targeted genes of these miRNAs with prognostic value were carried out. Results indicated that these targeted genes were closely related to the development and metastasis of tumors. In summary, our research has developed a prognostic model based on the expression of miRNAs related to necroptosis. This model might be used to predict the prognosis of LUAD accurately, which might be helpful in improving treatment efficacy of LUAD.

Surface restructuring of a perovskite-type air electrode for reversible protonic ceramic electrochemical cells.

Reversible protonic ceramic electrochemical cells (R-PCECs) are ideally suited for efficient energy storage and conversion; however, one of the limiting factors to high performance is the poor stability and insufficient electrocatalytic activity for oxygen reduction and evolution of the air electrode exposed to the high concentration of steam. Here we report our findings in enhancing the electrochemical activity and durability of a perovskite-type air electrode, Ba0.9Co0.7Fe0.2Nb0.1O3-δ (BCFN), via a water-promoted surface restructuring process. Under properly-controlled operating conditions, the BCFN electrode is naturally restructured to an Nb-rich BCFN electrode covered with Nb-deficient BCFN nanoparticles. When used as the air electrode for a fuel-electrode-supported R-PCEC, good performances are demonstrated at 650 °C, achieving a peak power density of 1.70 W cm-2 in the fuel cell mode and a current density of 2.8 A cm-2 at 1.3 V in the electrolysis mode while maintaining reasonable Faradaic efficiencies and promising durability.

Bacterial MazF/MazE toxin-antitoxin suppresses lytic propagation of arbitrium-containing phages.

Temperate phages dynamically switch between lysis and lysogeny in their full life cycle. Some Bacillus-infecting phages utilize a quorum-sensing-like intercellular communication system, the "arbitrium," to mediate lysis-lysogeny decisions. However, whether additional factors participate in the arbitrium signaling pathway remains largely elusive. Here, we find that the arbitrium signal induces the expression of a functionally conserved operon downstream of the arbitrium module in SPbeta-like phages. SPbeta yopM and yopR (as well as phi3T phi3T_93 and phi3T_97) in the operon play roles in suppressing phage lytic propagation and promoting lysogeny, respectively. We further focus on phi3T_93 and demonstrate that it directly binds antitoxin MazE in the host MazF/MazE toxin-antitoxin (TA) module and facilitates the activation of MazF's toxicity, which is required for phage suppression. These findings show events regulated by the arbitrium system and shed light on how the interplay between phages and the host TA module affects phage-host co-survival.

Mechanistic insights into the regulation of plant phosphate homeostasis by the rice SPX2 - PHR2 complex.

Phosphate (Pi) starvation response (PHR) transcription factors play key roles in plant Pi homeostasis maintenance. They are negatively regulated by stand-alone SPX proteins, cellular receptors for inositol pyrophosphate (PP-InsP) nutrient messengers. How PP-InsP-bound SPX interacts with PHRs is poorly understood. Here, we report crystal structures of the rice SPX2/InsP6/PHR2 complex and of the PHR2 DNA binding (MYB) domain in complex with target DNA at resolutions of 3.1 Å and 2.7 Å, respectively. In the SPX2/InsP6/PHR2 complex, the signalling-active SPX2 assembles into a domain-swapped dimer conformation and binds two copies of PHR2, targeting both its coiled-coil (CC) oligomerisation domain and MYB domain. Our results reveal that the SPX2 senses PP-InsPs to inactivate PHR2 by establishing severe steric clashes with the PHR2 MYB domain, preventing DNA binding, and by disrupting oligomerisation of the PHR2 CC domain, attenuating promoter binding. Our findings rationalize how PP-InsPs activate SPX receptor proteins to target PHR family transcription factors.

Corrigendum to "Scaffolds of bioactive glass (Bioglass®) combined with recombinant human bone morphogenetic protein -9 (rhBMP-9) for tooth extraction site preservation" [Heliyon 8 (1) (January 2022) e08796].

[This corrects the article DOI: 10.1016/j.heliyon.2022.e08796.].

AimR Adopts Preexisting Dimer Conformations for Specific Target Recognition in Lysis-Lysogeny Decisions of Bacillus Phage phi3T.

A bacteriophage switches between lytic and lysogenic life cycles. The AimR-AimP-AimX communication system is responsible for phage lysis-lysogeny decisions during the infection of Bacillus subtilis. AimX is a regulator biasing phage lysis, AimR is a transcription factor activating AimX expression, and AimP is an arbitrium peptide that determines phage lysogeny by deactivating AimR. A strain-specific mechanism for the lysis-lysogeny decisions is proposed in SPbeta and phi3T phages. That is, the arbitrium peptide of the SPbeta phage stabilizes the SPbeta AimR (spAimR) dimer, whereas the phi3T-derived peptide disassembles the phi3T AimR (phAimR) dimer into a monomer. Here, we find that phAimR does not undergo dimer-to-monomer conversion upon arbitrium peptide binding. Gel-filtration, static light scattering (SLS) and analytical ultracentrifugation (AUC) results show that phAimR is dimeric regardless of the presence of arbitrium peptide. Small-angle X-ray scattering (SAXS) reveals that the arbitrium peptide binding makes an extended dimeric conformation. Single-molecule fluorescence resonance energy transfer (smFRET) analysis reveals that the phAimR dimer fluctuates among two distinct conformational states, and each preexisting state is selectively recognized by the arbitrium peptide or the target DNA, respectively. Collectively, our biophysical characterization of the phAimR dynamics underlying specific target recognition provides new mechanistic insights into understanding lysis-lysogeny decisions in Bacillus phage phi3T.

Enhancements on Flame Resistance by Inorganic Silicate-Based Intumescent Coating Materials.

Flame-retardant coatings have drawn much attention in recent years. In this study, an inorganic sodium silicate-based intumescent flame-resistance coating with an excellent flameproof properties is developed by mainly utilizing sodium silicate as the ceramizable binder, via hydrolysis and self-condensation reaction. Fly ash, metakaoline, and wollastonite behave as supplement cementing materials. Major formulation encompasses the combination of the ammonium polyphosphate and pentaerythritol as the flame-retardant additives, and aluminum hydroxide or expandable graphite as the intumescence-improving filler agents. Expandable graphite was found to play an important role in the eventual performance of flame-resistance testing. The results showed that solid interaction forces can be formed between metakaoline and sodium silicate, resulting in a similar material to geopolymer with excellent physical properties. After high-temperature flame testing, a densely complex protective layer of carbon-char created on top of the robust silicon dioxide networks offers notable flame resistance. An optimal ratio in this inorganic intumescent coating contains sodium silicate-metakaoline (weight ratio = 9:1)-ammonium polyphosphate and pentaerythritol, aluminum hydroxide (3, 3, 10 wt.%)-expandable graphite (1 wt.%), which can create 4.7 times higher expansion ratio compared with neat sodium silicate matrix. The results of flame testing demonstrate only 387.1 °C and 506.3 °C on the back surface of steel substrate after one and three hours flaming (>1000 °C) on the other surface, respectively, which could meet the requirements according to the level of fire rating.