Colorectal cancer lymph node staining by activated carbon nanoparticles suspension in vivo or methylene blue in vitro

AIM:To investigate whether activated carbon nanoparticles suspension(ACNS) or methylene blue(MB) can increase the detected number of lymph nodes in colorectal cancer.METHODS:Sixty-seven of 72 colorectal cancer patients treated at our hospital fulfilled the inclusion criteria of the study which was conducted from December 2010 to February 2012.Seven patients refused to participate.Eventually,60 patients were included,and randomly assigned to three groups(20 in each group):ACNS group(group A),MB group(group B) and non-stained conventional surgical group(group C).In group A,patients received subserosal injection of 1 mL ACNS in a 4-quadrant region around the mass.In group B,the main artery of specimen was identified and isolated after the specimen was removed,and 2 mL MB was slowly injected into the isolated,stretched and fixed vessel.In group C,no ACNS and MB were injected.All the mesentery lymph nodes were isolated and removed systematically by visually inspecting and palpating the adipose tissue.RESULTS:No difference was observed among the three groups in age,gender,tumor location,tumor diameter,T-stage,degree of differentiation,postoperative complications and peritoneal drainage retention time.The total number of detected lymph nodes was 535,476 and 223 in the three groups,respectively.The mean number of detected lymph nodes per patient was significantly higher in group A than in group C(26.8 ± 8.4 vs 12.2 ± 3.2,P < 0.001).Similarly,there were significantly more lymph nodes detected in group B than in group C(23.8 ± 6.9 vs 12.2 ± 3.2,P < 0.001).However,there was no significant difference between group A and group B.There were 50,46 and 32 metastatic lymph nodes dissected in 13 patients of group A,10 patients of group B and 11 patients of group C,without significant differences among the three groups.Eleven of the 60 patients had insufficient number of detected lymph nodes(< 12).Only one patient with T 4a rectal cancer had 10 lymph nodes detected in group B,the other 10 patients were all from group C.Based on the different diameter categories,the number of detected lymph nodes in groups A and B was significantly higher than in group C.However,there was no statistically significant difference between group A and group B.The metastatic lymph nodes were not significant different among the three groups.Similarly,tumor location,T stage and tumor differentiation did not affect the staining results.Body mass index was a minor influencing factor in the two different staining methods.The stained lymph nodes can easily be identified from the mesenteric adipose tissues,and the staining time for lymph nodes was not significantly different compared with unstained group.None of the patients in groups A and B had drug-related complications.CONCLUSION:Both activated carbon nanoparticles suspension in vivo and methylene blue in vitro can be used as tracers to increase the detected number of lymph nodes in colorectal cancer.

Lymph Node Mapping with Carbon Nanoparticles and the Risk Factors of Lymph Node Metastasis in Gastric Cancer

The study aimed to examine the applicability of carbon nanoparticles as a tracer for lymph node mapping and the related factors of lymph node and No.8p subgroup metastasis in patients with gastric cancer.Clinical data of 50 patients with gastric cancer,who had not received treatment preoperatively and underwent gastrectomy in Department of Gastrointestinal Surgery,Wuhan Union Hospital,between October 2014 and August 2015,were retrospectively analyzed.These patients were found to have no distant metastasis preoperatively.Thirty-five out of 50 patients were subjected to lymphatic mapping technique using carbon nanoparticles as the tracer,and the rest 15 cases did not experience the lymphatic mapping and served as controls.The sensitivity,specificity,false positive rate and false negative rate were calculated according to the number of lymph nodes,and the staining and metastasis condition of lymph nodes.The diagnostic value of carbon nanoparticles on metastatic lymph nodes was evaluated.The relationship between the metastasis of lymph nodes or subgroup No.8p lymph nodes and clinicopathologic features was analyzed by χ^2-test or Fisher＇s exact test.All patients underwent D2 surgery（lymph node dissection including all the group 1 and group 2 nodes） plus the dissection of the subgroup No.8p lymph nodes.It was found that the average number of harvested lymph nodes in lymphatic mapping technique group（45.7±14.5） was greater than that in control group（39.2±11.7）,but the difference was not significantly different（P=0.138〉0.05）.The success rate,the accuracy,sensitivity,specificity and false negative rate was 97%,57%,28%,62% and 72% respectively.The metastasis of lymph nodes was correlated to the depth of cancer invasion（T stage）（P=0.004〈0.05）,and the metastasis of No.8p lymph nodes was correlated to the extent of lymph node involvement（N stage）（P=0.007〈0.05）.Six cases had lymph node metastasis in subgroup No.8p,and their TNM stages and clinical stages were as follows：T1N2M0 ⅡA,T3N3M0 ⅢB,T4 a N3M0 ⅢC,T4 a N3M0 ⅢC,T4 a N3M0 ⅢC,and T4 b N3M0 ⅢC.In conclusion,our study indicated that carbon nanoparticles failed to show good selectivity for metastatic lymph nodes;the result of lymphatic mapping does not achieve a satisfactory performance;the incidence of lymph node metastasis may increase,accompanying with the increase of the depth of cancer invasion;No.8p lymph node metastasis tends to occur for gastric carcinoma patients with the extent of lymph node metastasis over N2 stage.

Amyloid-β peptide aggregation and the influence of carbon nanoparticles

Soluble peptides or proteins can self-aggregate into insoluble, ordered amyloid fibrils under appropriate conditions. These amyloid aggregates are the hallmarks of several human diseases ranging from neurodegenerative disorders to sys- temic amyloidoses. In this review, we first introduce the common structural features of amyloid fibrils and the amyloid fibrillation kinetics determined from experimental studies. Then, we discuss the structural models of Alzheimer＇s amyloid- β （Aβ） fibrils derived from solid-state nuclear magnetic resonance spectroscopy. On the computational side, molecular dynamics simulations can provide atomic details of structures and the underlying oligomerization mechanisms. We finally summarize recent progress in atomistic simulation studies on the oligomerization of β （including full-length Af and its fragments） and the influence of carbon nanoparticles.

Targeted delivery of docetaxel to the metastatic lymph nodes:A comparison study between nanoliposomes and activated carbon nanoparticles

The objective of this study is to compare the targeting ability of activated carbon nanoparticles and nanoliposomes,which are used as carriers for delivering docetaxel(DTX)to the metastatic lymph nodes.In this study,we first prepared the DTX-loaded activated carbon nanoparticles(DTX-AC-NPs)by modifying the activated carbon with nitric acid oxidation and absorbing DTX in the concentrated nitro-oxide nanocarbon.We then prepared DTX-loaded nanoliposomes(DTX-LPs)by the proliposome method.The physiochemical properties of DTX-AC-NPs and DTX-LPs were carefully evaluated in vitro.The metastatic lymph node uptake and the injection site retention were investigated by analyzing the DTX concentration in metastatic lymph nodes and injection sites.The result showed that DTX-AC-NPs and DTX-LPs with suitable and stable physicochemical properties could be used for in vivo lymph node targeting studies.DTX-AC-NPs significantly increased DTX-AUC_((0-24)) and prolonged DTX-retention in metastatic lymph nodes compared to DTX-LPs and non-modified activate carbon in vivo.This study demonstrated activated carbon nanoparticles may be potential intralymphatic drug delivery system to preferentially target regional metastatic lymph nodes.

Identification of the Parathyroid Gland with Vasculature by Intraoperative Carbon Nanoparticles

Background: We aimed to investigate the ability of carbon nanoparticles to identify parathyroid glands with vasculature during thyroid surgery. Material and methods: Totally 42 patients with various thyroid diseases were selected for the prospective research of carbon nanoparticle injection used in thyroidectomy. Another 42 patients without receiving carbon nanoparticle injection were selected as the control group. All cases underwent total or subtotal bilateral thyroidectomy. Before the ligation of the superior and inferior poles of the thyriod lobes, 0.1 mL of a carbon nanoparticle suspension was injected into the two poles. Important tissues such as the recurrent laryngeal nerve, parathyroid gland with blood supply and the inferior thyroid artery were identified and protected. Results: The parathyroid glands with vasculature were not stained and thus remained the primary color in all cases, while abnormal thyroid tissues were stained black. After 5 minutes, thyroid lobes were injected with the carbon nanoparticle suspension and the original color of parathyroid glands was unchanged. Even the parathyroids with blood supply can be identified and protected. The number of parathyroid glands for autotransplantation was one in the test group and six in the control group. At one day after the thyroid surgery, hypocalcemia became detectable in four patients of the test group and in five of the control group. Twenty-four instances of hypoparathyroidism occurred at 1 day after surgery in the control group, while ten instances in the test group. Conclusion: Intraoperatvie carbon nanoparticle suspension injection is an effective and safe technique for guiding thyroid surgery. The carbon nanoparticle suspension plays an important role in identifying the vasculatural parathyroid glands, while protecting the physiologic function of the parathyroid glands during surgery.

Orientation in Nematic Liquid Crystals Doped with Orange Dyes and Effect of Carbon Nanoparticles

Some properties of nematic liquid crystal E7 doped with two disperse orange dyes used together and effect of addition of carbon nanoparticles （single walled carbon nanotube or fullerene C60） on them were studied. Two dyes （disperse orange 11 and 13） having high solubility and order parameter were used as co-dopants. A notable increase in order parameter was obtained comparing to that of liquid crystal doped with single dye. When carbon nanoparticles were used as dopant, a decrease in order parameter was observed at low temperatures while it increased at high temperatures. When applied voltage changed, the order parameter abruptly increased in its threshold value and saturated in higher voltages as expected. An appreciable change in textures was not observed with addition of dopants. This addition gave rise to an increase in nematic-isotropic phase transition temperatures compared with that of pure liquid crystal.

Conductive hydrogels incorporating carbon nanoparticles:A review of synthesis,performance and applications

As one of the most rapidly expanding materials,hydrogels have gained increasing attention in a variety of fields due to their biocompatibility,degradability and hydrophilic properties,as well as their remarkable adhesion and stretchability to adapt to different surfaces.Hydrogels combined with carbon-based materials possess enhanced properties and new functionalities,in particular,conductive hydrogels have become a new area of research in the field of materials science.This review aims to provide a comprehensive overview and up-to-date examination of recent developments in the synthesis,properties and applications of conductive hydrogels incorporating several typical carbon nanoparticles such as carbon nanotubes,graphene,carbon dots and carbon nanofibers.We summarize key techniques and mechanisms for synthesizing various composite hydrogels with exceptional properties,and represented applications such as wearable sensors,temperature sensors,supercapacitors and human-computer interaction reported recently.The mechanical,electrical and sensing properties of carbon nanoparticles conductive hydrogels are thoroughly analyzed to disclose the role of carbon nanoparticles in these hydrogels and key factors in the microstructure.Finally,future development of conductive hydrogels based on carbon nanoparticles is discussed including the challenges and possible solutions in terms of microstructure optimization,mechanical and other properties,and promising applications in wearable electronics and multifunctional materials.

Endoscopic ultrasound-guided injection of carbon nanoparticles suspension to label rectal cancer before neoadjuvant chemoradiotherapy:a retrospective cohort study

Background:Localization of the primary tumor and ensuring safe distal surgical margins(DSMs)following neoadjuvant chemoradiotherapy(nCRT)are challenging in locally advanced rectal cancers(LARCs).This study investigated the effectiveness of carbon nanoparticles suspension(CNS)for labeling the primary tumor and allowing precise tumor resection after nCRT.Methods:Clinicopathological data of LARC patients who underwent nCRT followed by laparoscopic radical anal preservation surgery at our center between January 2018 and February 2023 were prospectively collected.The patients were divided into the CNS tattooed(CNS)and non-tattooed(control)groups.In the CNS group,CNS was injected in four quadrants on the anal side 1 cm away from the lower tumor margin.DSMs were determined through intraoperative distal rectal examination in the control group and observation of CNS tattoos in the CNS group.DSM lengths and positive DSM rates were compared between the two groups to analyse the feasibility and effectiveness of CNS for labeling LARCs before nCRT.Results:There was no statistically significant difference in the basic demographic data,effectiveness of nCRT,or post-operative recovery rates between the two groups(all P>0.05).In the CNS group,CNS tattoos were observed on the outside of the rectal wall,with an overall efficiency of 87.1%(27/31).The CNS group had fewer positive DSMs and safer DSM lengths(2.73±0.88 vs 2.12±1.15 cm,P=0.012)than the control group(P<0.05).Conclusions:Endoscopic ultrasound-guided injection of CNS tattoos before nCRT could effectively label the LARCs,ensuring safe DSMs during anus-preserving surgeries(Chictr.org.cn No.:ChiCTR2300068991).

Toxicological and Life-Cycle Perspectives on Waste-Derived Nanoparticles

Many nanoparticles have been created over the last few decades using a variety of techniques and used to develop environmental technology, including water treatment, the detection of persistent contaminants, and soil and water remediation. The studies of alternative inputs for nanoparticle production as well as the use of green synthesis techniques are driven by the field of materials science and engineering’s growing interest in increasing the sustainability of the processes involved in their production. In this paper, we begin by providing an overview of the fundamental principles of producing nanoparticles from different sources, such as plastic, electronic, metal, and industrial waste. We elaborate on key facts of waste identification as a workable input for the treatment and recovery of metal and carbon-based nanoparticles. We next go over several controlling factors that play a role in creating nanoparticles, pointing out probable conclusions as we go. Then, we show some instances of waste-derived nanoparticles used in a proof-of-concept experiment of technology for applications in water quality and safety. Before scaling up production and implementing waste-derived nanoparticles, there are several present problems from the toxicological and life-cycle perspectives that must be taken into account.

Astonishingly distinct lubricity difference between the ionic liquid modified carbon nanoparticles grafted by anion and cation moieties

The astonishingly distinct lubricity difference between the ionic liquid modified carbon nanoparticles grafted by anion and cation moieties(A-g-CNPs and C-g-CNPs)was well established as additives of polyethylene glycol(PEG200).The peripheral anion moieties and positively charged inner parts of C-g-CNPs could successively absorb onto the friction interfaces by electrostatic interactions to form the organic-inorganic electric double layer structures,tremendously boosting the lubricity of PEG200.Contrarily,the preferentially electrostatic adsorption of negatively charged inner parts but repulsion of the peripheral cation moieties determined the weak embedded stability of A-g-CNPs between the friction interfaces,even impairing the lubricity of PEG200.This work can offer solidly experimental and theoretical guidance for designing and developing the high-performance nanoadditives modified by ionic molecules.

A novel nanofluid of modified carbon black nanoparticles for enhanced oil recovery in low permeability reservoirs

A novel nanofluid of modified carbon black(MCB)nanoparticles was initially developed for enhanced oil recovery(EOR)in low permeability reservoirs.The MCB nanoparticles were obtained via a three-step reaction involving modification by oxidation,acyl chlorination,and activated grafting.MCB nano-particles were spherically dispersed,with an average size of 72.3 nm.Compared with carbon black(CB)nanoparticles,dispersed MCB nanoparticles can effectively reduce the oil-water interfacial tension(IFT)to 10^(-2)mN/m and change the surface wettability of sand particles.Based on the results of core flooding experiments,the MCB nanoparticles exhibited a better EOR capacity than surfactants and CB nano-particles,and the final oil recovery was significantly increased by 27.27%.The core scanning test showed that the MCB nanoparticles could plug high permeability channels by adsorbing onto the surfaces of sand particles and forming larger aggregates that bridge across pores or throats,resulting in a higher swept volume.The synergistic effects of improved swept volume and oil displacement efficiency were the EOR mechanisms of the MCB nanoparticles.The studies indicate that these MCB nanoparticles have excellent potential for EOR in low permeability reservoirs.

Multicolor Luminescent Carbon Nanoparticles： Synthesis, Supramolecular Assembly with Porphyrin, Intrinsic Peroxidase-Like Catalytic Activity and Applications

Luminescent carbon nanoparticles （CNPs） are newcomers to the world of nanomaterials and have shown great impact in health and environmental applications as well as being promising building blocks for future nanodevices because of their fascinating photoluminescence and potential to serve as nontoxic replacements for traditional heavy-metals-based quantum dots. Herein, fluorescent CNPs have been prepared from candle soot by re fluxing with HNO3 and subsequently separated by a single centrifugation. The CNPs can be represented by the empirical formula C1Ho.677Oo.586No.o15Nao.069, and have a size of 20-100 nm, height of 3.0 nm, lifetime of 7.31 ns ＋ 0.06 ns and quantum yield of -1.7%. Further studies demonstrate that： （1）the as-prepared CNPs exhibit excellent stability in biological media and their luminescence intensity does not change with ionic strength or pH in the physiological and pathological range of pH 4.5-8.8; （2） CNPs can act as electron donors and transporters and porphyrin can assemble onto CNPs through electrostatic and ^-stacking interactions to form porphyrin-CNPs supramolecular composites; （3）CNPs have strong intrinsic peroxidase-like activity. Based on this intrinsic peroxidase activity, a simple, cheap, and highly selective and sensitive colorimetric and quantitative assay has been developed for the detection of glucose levels. This assay has been used to analyze real samples, such as diluted blood and fruit juice.

Surface chemistry of carbon nanoparticles functionally select their uptake in various stages of cancer cells

Relationship of the surface physicochemical characteristics of nanoparticles with their interactions with biological entities may provide critical information for nanomedicinal application. Here, we report the systematic synthesis of sub-50 nm carbon nanoparticles （CNP） presenting neutral, anionic, and cationic surface functionalities. A subset of CNPs with -10, 20, and 40 nm hydrodynamic sizes were synthesized with neutral surface headgroups. For the first time, the cellular internalization of these CNPs was systematically quantified in various stages of breast cancer cells （early, late, and metastatic）, thereby providing a parametric assessment of charge and size effects. Distinct activities were observed when these systems interacted with cancer cells in various stages. Our results indicated that metastatic breast cancer could be targeted by a nanosystem presenting anionic phosphate groups. On the contrary, for patients in late stage of cancer, drugs could be delivered with sulfonate functionalized carbon nano- particles, which have higher probability of intracellular transport. This study will facilitate the better understanding of nanoparticle-biological entity interaction, and the integration of this knowledge with pathophysiology would promote the engineering of nanomedicine with superior likelihoods of crossing the endocytic ＂barrier＂ for drug delivery inside cancerous cells.

Preparation of highly luminescent nitrogen and sulfur co-doped carbon nanoparticles for iron(Ⅲ)ions detection and cell imaging

Highly photoluminescent nitrogen and sulfur co-doped carbon nanoparticles（CNPs） ca. 56 nm have been prepared through a green one-step hydrothermal synthesis route by using millet powder as carbon sources, in which the nitrogen and sulfur co-doping improves the photoluminescent efficiency of the CNPs. The as-prepared CNPs display excellent fluorescent properties and low biotoxicity with a relatively high quantum yield of 30.4%, which have been applied for bioimaging and highly sensitive and selective detection of iron（III） ions.

Stainless steel cloth modified by carbon nanoparticles of Chinese ink as scalable and high-performance anode in microbial fuel cell

Microbial fuel cells(MFCs) have various potential applications.However,anode is a main bottleneck that limits electricity production performance of MFCs.Herein,we developed a novel anode based on a stainless steel cloth(SC) modified with carbon nanoparticles of Chinese ink(Cl) using polypyrrole(PPy)as a building block(PPy/Cl/SC).After modification,PPy/Cl/SC showed a 30% shorten in start-up time(36.4 ± 3.3 h vs.52.3± 1.8 h),33% increase in the maximum current(12.4 ± 1.4 mA vs.9.3± 0.95 mA),and2.3 times higher in the maximum power density of MFC(61.9 mW/m^(2) vs.27.3 mW/m^(2)),compared to Ppy/SC.Experimental results revealed that carbon nanoparticles were able to cover SC uniformly,owing to excellent dispersibility of carbon nanoparticles in Cl.The attachment of carbon nanoparticles formed a fluffy layer on SC increased the electrochemically-active surface area by 1.9 times to 44.5 cm^(2).This enhanced electron transfer between the electrode and bacteria.Further,embedding carbon nanoparticles into the PPy layer significantly improved biocompatibility as well as changed functional group contents,which were bene ficial to bacteria adhesion on electrodes.Taking adva ntage of high mechanical strength and good conductivity,a large-size PPy/Cl/SC was successfully prepared(50×60 cm^(2))demonstrating a promising potential in practical applications.This simple fabrication strategy offers a new idea of developing low cost and scalable electrode materials for high-performance energy harvesting in MFCs.

Pt nanoparticles entrapped in ordered mesoporous carbons:An efficient catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives

Pt nanoparticles entrapped in ordered mesoporous CMK-3 carbons with p6mm symmetry were prepared using a facile impregnation method, and the resulting materials were characterized using X-ray diffraction spectroscopy, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The Pt nanoparticles were highly dispersed in the CMK-3 with 43.7% dispersion. The Pt/CMK-3 catalyst was an effective catalyst for the liquid-phase hydrogenation of nitrobenzene and its derivatives under the experimental conditions studied here. The Pt/CMK-3 catalyst was more active than commercial Pt/C catalyst in most cases. A highest turnover frequency of 43.8 s-1 was measured when the Pt/CMK-3 catalyst was applied for the hydrogenation of 2-methyl-nitrobenzene in ethanol under optimal conditions. It is worthy of note that the Pt/CMK-3 catalyst could be recycled easily, and could be reused at least fourteen times without any loss in activity or selectivity for the hydrogenation of nitrobenzene in ethanol.

A green synthesis of carbon nanoparticles from honey and their use in real-time photoacoustic imaging

Imaging sentinel lymph nodes （SLN） could provide us with critical information about the progression of a cancerous disease. Real-time high-resolution intrao- perative photoacoustic imaging （PAI） in conjunction with a near-infrared （NIR） probe may offer opportunities for the immediate imaging for direct identification and resection of SLN or collecting tissue samples. In this work a commercially amenable synthetic methodology is revealed for fabricating luminescent carbon nanoparticles with rapid clearance properties. A one-pot ＂green＂ technique is pursued, which involved rapid surface passivation of carbon nanopartides with organic macromolecules （e.g., polysorbate, polyethyleneglycol） in solvent-free conditions. Interestingly, the naked carbon nanoparticles are derived for the first time, from commercial food grade honey. Surface coated particles are markedly smaller （-7 nm） than previously explored particles （gold, single-walled carbon nanotubes, copper） for SLN imaging. The results indicate an exceptionally rapid signal enhancement （-2 min） of the SLN. Owing to their strong optical absorption in the NIR region, tiny size and rapid lymphatic transport, this platform offers great potential for faster resection of SLN and may lower complications caused in axillary investigation by mismarking with dyes or low-resolution imaging techniques.

Tailoring the Meso-Structure of Gold Nanoparticles in Keratin-Based Activated Carbon Toward High-Performance Flexible Sensor

Flexible biosensors with high accuracy and reliable operation in detecting pH and uric acid levels in body fluids are fabricated using well-engineered metaldoped porous carbon as electrode material.The gold nanoparticles@N-doped carbon in situ are prepared using wool keratin as both a novel carbon precursor and a stabilizer.The conducting electrode material is fabricated at 500℃ under customized parameters,which mimics A-B type(two different repeating units) polymeric material and displays excellent deprotonation performance(pH sensitivity).The obtained pH sensor exhibits high pH sensitivity of 57 mV/pH unit and insignificant relative standard deviation of 0.088%.Conversely,the composite carbon material with sp^2 structure prepared at 700℃ is doped with nitrogen and gold nanoparticles,which exhibits good conductivity and electrocatalytic activity for uric acid oxidation.The uric acid sensor has linear response over a range of 1-150 μM and a limit of detection 0.1 μM.These results will provide new avenues where biological material will be the best start,which can be useful to target contradictory applications through molecular engineering at mesoscale.

Synthesis and characterization of carbon-coated cobalt ferrite nanoparticles

Cobalt ferrite nanoparticles（CFNPs） were prepared via a reverse micelle method. The CFNPs were subsequently coated with carbon shells by means of thermal chemical vapor deposition（TCVD）. In this process, acetylene gas（C2H2） was used as a carbon source and the coating was carried out for 1, 2, or 3 h at 750℃. The Ar/C2H2 ratio was 10：1. Heating during the TCVD process resulted in a NP core size that approached 30 nm; the thickness of the shell was less than 10 nm. The composition, structure, and morphology of the fabricated composites were characterized using X-ray diffraction, simultaneous thermal analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and selected-area diffraction. A vibrating sample magnetometer was used to survey the samples＇ magnetic properties. The deposited carbon shell substantially affected the growth and magnetic properties of the CFNPs. Micro-Raman spectroscopy was used to study the carbon coating and revealed that the deposited carbon comprised graphite, multiwalled carbon nanotubes, and diamond-like carbon. With an increase in coating time, the intensity ratio between the amorphous and ordered peaks in the Raman spectra decreased, which indicated an increase in crystallite size.

Apparent 1^st order rate constant of photodegradation of formaldehyde by carbon containing TiO2 nanoparticles

The apparent 1^st order rate constant of photodegradation of formaldehyde by carbon containing TiO2 nanoparticles has been investigated by numerical integration of mass transfer equation with measured degradation degree using a tubular photoreactor. The carbon containing TiO2 nanoparticles are synthesized by the oxidation of TiCl4 in propane/air flame CVD process with futile fraction up to 0.3 and carbon mass fractions up to 0.22, respectively. Thin TiO2 film is coated on the wall of the tubular reactor by sedimentation method. Effects of rutile mass fraction and carbon content have been examined on the apparent 1 ^st order rate constant and results show that, at 570ppm of formaldehyde loaded air stream, 80% relative humidity and about 100nm thin TiOa film, the 1^st order rate constant increases with increasing rutile mass fraction up to 0.3, occurs a maximum at the carbon content of about 5% by weight and is about 2.5 times of that at carbon content about zero or above 10%.