Nanographene with Multiple Embedded Heptagons: Cascade Radical Photocyclization.

Although heptagons are widely found in graphenic materials, the precise synthesis of nanocarbons containing heptagons remains a challenge, especially for the nanocarbons containing multiple-heptagons. Herein, we show that photo-induced radical cyclization (PIRC) can be used to synthesize multi-heptagon-embedded nanocarbons. Notably, a nanographene containing six heptagons (1) was obtained via a six-fold cascade PIRC reaction. The structure of 1 was clearly validated and showed a Monkey-saddle-shaped conformation. Experimental bond analysis and theoretical calculations indicated that the heptagons in 1 were non-aromatic, whereas the peripheral rings were highly aromatic. Compared to planar nanographene with the same number of π electrons, 1 had a similar optical gap due to a compromise between the decreased conjugation in the wrapped structure and enhanced electronic delocalization at the rim. Electrochemical studies showed that 1 had low-lying oxidation potentials, which was attributed to the nitrogen-doping.

Prognostic Significance of Pretreatment Prognostic Nutritional Index (PNI) in Patients with Nasopharyngeal Carcinoma: A Meta-Analysis.

OBJECTIVE: Previous studies have investigated the pretreatment prognostic nutritional index (PNI) as a prognostic factor in patients with nasopharyngeal carcinoma (NPC); however, the results remained inconsistent. We aimed to assess the prognostic value of PNI in patients with NPC through conducting meta-analysis. Methods: Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for low PNI of overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), loco-regional recurrence-free survival (LRFS), and cancer-specific survival (CSS). Results: Totally, eight studies involving 4299 patients were included in this meta-analysis. A low pretreatment PNI was associated with poor OS (HR = 1.86, 95% CI = 1.55-2.33, P < 0.001), DMFS (HR = 2.03, 95% CI = 1.69-2.44, P < 0.001), PFS (HR = 1.57, 95% CI = 1.31-1.90, P < 0.001), and CSS (HR = 2.29, 95% CI = 1.54-3.42, P < 0.001). The subgroup analysis showed that low PNI remained a significant factor for poor OS, DMFS, and PFS irrespective of treatment, country, and cutoff value of PNI. In addition, low PNI was correlated to female gender (OR = 1.35, 95% CI = 1.12-1.62, P = 0.002), older age (OR = 1.75, 95% CI = 1.17-2.62, P = 0.007), and T3-T4 stage (OR = 1.27, 95% CI = 1.06-1.53, P = 0.011). Conclusions: A low PNI was associated with poor survival outcomes in patients with NPC. Moreover, PNI could serve as an index to help guide clinical management for older patients.

Hemostatic Effect of Aminated Multiwalled Carbon Nanotubes/Oxidized Regenerated Cellulose Nanocomposites.

We have investigated the covalent conjugation of aminated multiwalled carbon nanotubes (MWCNTNH2)s with Oxidized Regenerated Cellulose (ORC) in order to enhance the hemostatic effect. The MWCNT-NH2s were prepared by functionalization of pristine MWCNTs (pMWCNTs) using amine groups. Neat ORC gauze and MWCNT-NH2s were reacted using glutamic acid as cross linking bridge. We investigated an amination of pMWCNTs as well as the dispersion of MWCNT-NH2s in the ORC gauze as matrix and their interfacial interactions by SEM and FT-IR. The results revealed that relatively strong interaction exists between aminated MWCNTs and the ORC macromolecules. The hydrophilicity test results in the significant increment of water uptake of MWCNT-NH2s/ORC composites with increasing the concentration of MWCNT-NH2s in composite. The in-vitro procoagulation test shows that the MWCNT-NH2s/ORC gauzes have significant procoagulant activity. The hemostatic evaluation of MWCNT-NH2s/ORC composites on rabbits shows that the aminated MWCNTs increase the rate of blood stopping and hence they decrease the blood loosing from injured sites. Hemostatic evaluation indicates that the MWCNT-NH2s/ORC gauze has a valuable hemostatic performance. The products of platelets release reaction, activated platelets glycoprotein and activated clotting enzymes were increased simultaneously. The mechanism of the hemostasis for MWCNT-NH2s/ORC gauze is discussed.

Gold modified polydopamine coated mesoporous silica nano-structures for synergetic chemo-photothermal effect.

Near infrared (NIR) responsive agents have attracted a great attention in nanomedicine due to their efficient photothermal effect (PTE) and eco-friendly nature. In our study, a novel kind of nanostructure were developed based on mesoporous silica nanoparticles (MSN) loaded doxorubicin(DOX) core and polydopamine-gold nanoparticles shell (PDA-AuNPs), the system was designed for combined chemo and photothermal therapy into one system. The designed nanostructure were thoroughly characterized to confirm their structure and to ensure their efficiency as cargo delivery system (DDS). The pH controlled release behavior of DOX from the designed nanostructures was investigated, approximately 60% of DOX was released over 48 h. Under NIR irradiation, the nanoparticles exhibited good photothermal stability and a high photothermal conversion efficiency of approximately 49%. Importantly, the MSN@DOX-PDA-AuNPs nanostructures showed a synergetic photo and chemotherapeutic effect, with the enhanced DOX release by 19% over 15 h and 15.42% over 250 min with 4 cycles of NIR laser irradiation. The combined chemo-photothermal in an acidic environment and under NIR irradiation was successfully proved.

High-Contrast SEM Imaging of Supported Few-Layer Graphene for Differentiating Distinct Layers and Resolving Fine Features: There is Plenty of Room at the Bottom.

For supported graphene, reliable differentiation and clear visualization of distinct graphene layers and fine features such as wrinkles are essential for revealing the structure-property relationships for graphene and graphene-based devices. Scanning electron microscopy (SEM) has been frequently used for this purpose where high-quality image contrast is critical. However, it is surprising that the effect of key imaging parameters on the image contrast has been seriously undermined by the graphene community. Here, superior image contrast of secondary electron (SE) images for few-layer graphene supported on SiC and SiO2 /Si is realized through simultaneously tuning two key parameters-acceleration voltage (Vacc ) and working distance (WD). The overlooked role of WD in characterizing graphene is highlighted and clearly demonstrated. A unified model of Vacc and WD dependence of three types of SE collected by the standard side-attached Everhart-Thornley (E-T) SE detector is conceptually developed for mechanistically understanding the improved mass thickness contrast for supported few-layer graphene. The findings reported here will have important implications for effective characterizations of atomically thick 2D materials and devices.

Synthesis and evaluation of water soluble pH sensitive poly (vinyl alcohol)-doxorubicin conjugates.

The accuracy of spatiotemporal control cargo delivery and release are primordial to enhance the therapeutic efficiency and decrease the undesirable effects, in this context a novel prodrug were developed based on biocompatible polyvinyl alcohol (PVA) substrate. PVA was conjugated to doxorubicin (PVA-DOX) via an acid-labile hydrazone linkage. PVA was first functionalized with acidic groups, then reacted with hydrazine hydrate to form an amide bond. The amine group of PVA hydrazide was linked to carbonyl group (C = O) of DOX to form a pH sensitive hydrazone bond. The molecular structure of the PVA-DOX was confirmed by FTIR, XPS, and 1H-NMR analysis methods. The degree of grafting were evaluated by TGA and confirmed by XPS, which reveals the successful bond attachment of DOX to PVA. Our findings confirm pH dependent DOX release from PVA-DOX prodrug with faster release rate in acidic environment (pH 5.0, pH 6.0) and slower release rate in neutral pH environment (pH 7.4). Compared to the primary DOX, our synthesized PVA-DOX conjugates could exhibit a promising therapeutic effect, high biocompatibility and zero premature release. The results prove the successful synthesis of PVA-DOX conjugates with high efficiency.

Functional polymer materials affecting cell attachment.

This review discusses the functional polymer materials effect on the cell adhesion. The applied polymer materials for the cell adhesion purpose was prepared based on organic fibers and biocompatible hydrogel. On the other hand, the active peptides are incorporated into the polymer materials substrate via the cysteine-containing peptides and N-hydroxysuccinimide-active group. Cancer cells and normal cells were presented for the selective adhesion via the introduced polymer materials substrate containing active peptides including Arginine-Glycine-Aspartic and Isoleucine-Lysine-Valine-Alanine-Valine sequence peptides. This selectivity is revealed by a significant cooperativity between specific and non-specific cell adhesion. This study is of a great impact for the design of the polymeric structures for cell attachment.

Spatio-temporal control strategy of drug delivery systems based nano structures.

The drug instability, toxicity and the barrier to the target area necessitate a suitable drug delivery system with an external or internal control of the release. Spatio-temporal control using a surface functionalized nano-carrier seems to be the best alternative for guided drug delivery and release. This manuscript provides a broad spectrum about the drug carrier interface modification to cover the need for temporal drug delivery control under neglect side effects. On the other hand, recent advances related to the drug vehicle are highlighted, besides physical (Electric field, magnetic field, light) or mechanical (Ultrasound, mechanical strain), chemical (pH, redox gradient, enzyme) stimuli mediated DDS. Precisely, the paper focus on the NIR light as an effective external stimulus for remotely-triggered DDS. NIR responsive drug delivery systems are considered as novel drug modality that ensures an eco-friendly spatiotemporal control and an administrated meditation. This study also investigated the NIIR spectroscopy (NIRS) combined with partial least square (PLS) for quantitative analysis of a polyvinyl alcohol based prodrug (PVA-DOX) in order to reveal the high potential of NIRS for drug release monitoring and the extraction of concise calibration models.

Non-contact analysis of the adsorptive ink capacity of nano silica pigments on a printing coating base.

Near infrared spectra combined with partial least squares were proposed as a means of non-contact analysis of the adsorptive ink capacity of recording coating materials in ink jet printing. First, the recording coating materials were prepared based on nano silica pigments. 80 samples of the recording coating materials were selected to develop the calibration of adsorptive ink capacity against ink adsorption (g/m2). The model developed predicted samples in the validation set with r2  = 0.80 and SEP = 1.108, analytical results showed that near infrared spectra had significant potential for the adsorption of ink capacity on the recording coating. The influence of factors such as recording coating thickness, mass ratio silica: binder-polyvinyl alcohol and the solution concentration on the adsorptive ink capacity were studied. With the help of the near infrared spectra, the adsorptive ink capacity of a recording coating material can be rapidly controlled.

Synthesis and properties of poly[p-(2,5-dihydroxy)-phenylenebenzobisoxazole] fiber.

The novel polymer poly[p-(2,5-dihydroxy)-phenylenebenzobisoxazole] (PBOH) fiber was synthesized in the presence of 2,5-dihydroxyterephthalicacid (DHTA) and 4,6-diamino-1,3-benzenediol in poly(phosphoric acid) (PPA) using typical polycondensation conditions. The crystalline solutions of liquid PBOH in PPA were spun into fibers using dry-jet wet spinning. Furthermore, the thermostability and mechanical properties of PBOH were compared with poly(p-phenylene-2,6-benzoxazole) (PBO) in order to investigate the relationship between the chain structure and properties. The results indicated that the thermal degradation temperature of PBOH was above 750K and the tensile strength of the PBOH fiber was 3.1GPa, which were much lower than those of PBO fiber. The compressive strength of PBOH fiber was 331 M Pa, which was slightly higher than that of PBO fiber. In addition, molecular simulation was employed to explain why the compressive strength of PBOH fiber did not increase significantly compared to PBO fiber.