Direct transfer of graphene onto flexible substrates.

In this paper we explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate, which needs to be removed afterward. Various substrates of general interest in research and industry were studied in this work, including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate's hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate current processes and open up directions for applications of chemical vapor deposition graphene on flexible substrates. A broad range of applications can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene.

Familial isolated primary hyperparathyroidism/hyperparathyroidism-jaw tumour syndrome caused by germline gross deletion or point mutations of CDC73 gene in Chinese.

OBJECTIVE: Hyperparathyroidism-jaw tumour syndrome (HPT-JT) and familial isolated primary hyperparathyroidism (FIHP) are two subtypes of familial primary hyperparathyroidism, which are rarely reported in Chinese population. Here, we reported three FIHP families and one HPT-JT family with long-term follow-up and genetic analysis. DESIGN AND METHODS: A total of 22 patients, from four FIHP/HPT-JT families of Chinese descent, were recruited and genomic DNA was extracted from their peripheral blood lymphocytes. Direct sequencing for MEN1, CDC73, CASR gene was conducted. Reverse transcription PCR (RT-PCR) and quantitative real-time PCR (qRT-PCR) were used to study the effect of splice site mutations and gross deletion mutations. Immunohistochemistry was performed to analyse parafibromin expression in parathyroid tumours. Genotype-phenotype correlations were assessed through clinical characteristics and long-term follow-up data. RESULTS: Genetic analysis revealed four CDC73 germline mutations that were responsible for the four kindreds, including two novel point mutation (c.157 G>T and IVS3+1 G>A), one recurrent point mutation (c.664 C>T) and one deletion mutation (c.307+?_513-?del exons 4, 5, 6). RT-PCR confirmed that IVS3+1 G>A generated an aberrant transcript with exon3 deletion. Immunohistochemical analysis demonstrated reduced nuclear parafibromin expression in tumours supporting the pathogenic effects of these mutations. CONCLUSIONS: This study supplies information on mutations and phenotypes of HPT-JT/FIHP syndrome in Chinese. Screening for gross deletion and point mutations of the CDC73 gene is necessary in susceptible subjects.

In vitro protoscolicidal effects of high-intensity focused ultrasound enhanced by a superabsorbent polymer.

Echinococcus granulosus, the etiologic agent of cystic echinococcosis in humans and other animal hosts, is distributed worldwide. Echinococcosis is an increasing public health and socioeconomic concern. The present work evaluated whether or not a superabsorbent polymer (SAP) could enhance the damage efficacy of high-intensity focused ultrasound (HIFU) on the viability of E. granulosus protoscolices in vitro. HIFU of 100 W acoustic power and 0.01 g superabsorbent polymer were used to treat 5,000 protoscolices in 2-ml protoscolices suspension. After different HIFU exposure time (5, 10, 20, 30, 40, 50, and 60 s, respectively), the temperature of protoscolices suspension was taken, and the treated protoscolices were stained by trypan-blue exclusion assay, and their structures were observed by light microscopy. To better understand the biological mechanisms responsible for the deaths of protoscolices, the activity of succinate dehydrogenase (SDH) of the protoscolices treated with HIFU was examined. The temperature of protoscolices suspension treated with HIFU rose slowly, and the death rate of protoscolices was 73.7 % in the group of HIFU treatment time of 40 s; however, with the same HIFU treatment time of 40 s, the temperature of protoscolices suspension in the group of HIFU combined with SAP rose quickly, and the death rate of protoscolices was 100 %. The same protoscolicidal effect (100 %) of HIFU of 100 W acoustic power combined with SAP was also observed in the groups of HIFU treatment time of 50 and 60 s, respectively. The dead protoscolices were stained to blue, shrunken and black calcareous corpuscles, and disordered and decreasing hooks though of intact membrane, as well as some protoscolices lost hooks and tore open on membrane were observed. In the group of HIFU combined with SAP, it was found that the superabsorbent polymer was surrounded by the spoiled, and the destruction of protoscolices was much stronger than in the group of HIFU. The dead protoscolices exhibited the reduction or absence of SDH staining intensity in the parenchymal cell and calcareous corpuscles after HIFU irradiation, where a large number of necrotic cells were evident. These results suggested that HIFU could induce the damage and loss of viability of protoscolices; SAP could enhance the HIFU energy focused and cause more severe destruction efficacy on protoscolices; and mitochondrial energetic function is involved in the regulation of cell-death pathways of protoscolices.

Synthesis of monolayer hexagonal boron nitride on Cu foil using chemical vapor deposition.

Hexagonal boron nitride (h-BN) is very attractive for many applications, particularly, as protective coating, dielectric layer/substrate, transparent membrane, or deep ultraviolet emitter. In this work, we carried out a detailed investigation of h-BN synthesis on Cu substrate using chemical vapor deposition (CVD) with two heating zones under low pressure (LP). Previous atmospheric pressure (AP) CVD syntheses were only able to obtain few layer h-BN without a good control on the number of layers. In contrast, under LPCVD growth, monolayer h-BN was synthesized and time-dependent growth was investigated. It was also observed that the morphology of the Cu surface affects the location and density of the h-BN nucleation. Ammonia borane is used as a BN precursor, which is easily accessible and more stable under ambient conditions than borazine. The h-BN films are characterized by atomic force microscopy, transmission electron microscopy, and electron energy loss spectroscopy analyses. Our results suggest that the growth here occurs via surface-mediated growth, which is similar to graphene growth on Cu under low pressure. These atomically thin layers are particularly attractive for use as atomic membranes or dielectric layers/substrates for graphene devices.

Integrated microfluidic immunoassay for the rapid determination of clenbuterol.

An integrated microfluidic immunoassay system was established for high throughput analysis of clenbuterol. This system consisted of an integrated microchip and a linear confocal laser induced fluorescence (LIF) scanner. The microchip was composed of three layers: a fluidic channel layer, a PDMS membrane layer and a pneumatic control layer. The multi-layer chip was integrated with 36 pneumatic micro-valves and multiple micro-pumps to realize the flexible reagent delivery, facilitating the automatic assays with less consumption of samples and reduced analysis time. The homemade LIF scanner was able to simultaneously detect multi-channels and provide the potential capability of high throughput assays. The performance of the system was demonstrated by the determination of clenbuterol, one of the most widely used beta-agonists. Under the optimal conditions, the linear range and the limit of detection of clenbuterol were 0 approximately 5.0 ng mL(-1) and 0.088 ng mL(-1), respectively. The recovery rates determined with pig urine samples of 1.0 ng mL(-1) and 2.0 ng mL(-1) were 98.74% and 102.51% (n = 3), respectively. The total detection time was less than 30 min. The system had the potential application for rapid detection of multiple beta-agonists in clinical, pharmaceutical and chemical analyses.

[Impact of volatile sulphur compounds in periodontal pockets on initial periodontal therapy].

OBJECTIVE: To investigate the relationship of volatile sulphur compounds((VSC)levels in periodontal pockets with severity of periodontitis, and the impact of VSC on the result of initial periodontal therapy. METHODS: Twenty-five patients with chronic periodontitis(CP)(13 males and 12 females with average age of 35) were included in this study. Clinical periodontal parameters, plaque index, probing depth(PD), attachment loss(AL), and bleeding on probing(BOP) were recorded before and 3 months after the initial therapy. VSC levels were measured with a portable monitor in a digital score ranging from 0.0 to 5.0. All of 5 054 sites for 840 teeth were included in this study. RESULT: Before treatment the percentage of VSC-positive sites was 17.1%, 52.3% and 86.0% for shallow (PD<3 mm), moderate(PD 4-6 mm) and deep (PD>7 mm) pocket, respectively (P<0.001). In most VSC-positive sites the VSC levels were<1.0. Percentage of sites with a high VSC levels was significantly different among three groups (P<0.01). All clinical parameters in VSC-negative sites were reduced significantly following the initial therapy. The reduction of PD and AL in VSC-positive sites by treatment was less marked than that in VSC-negative sites. CONCLUSION: VSC in periodontal pockets may be a potential indicator for detecting severity of CP and a useful predictor for therapeutic success.

[Investigation on level and influencing factors of first aid knowledge among dentists in Sichuan province].

OBJECTIVE: The study aims to investigate the cognition degree and influencing factors of first aid knowledge among dentists in Sichuan province, and to provide suggestions for the training of oral clinician. METHODS: A questionnaire was designed for this study. It included the basic situation of population, first aid knowledge level, emergency situation often encountered in stomatology clinic, first aid training situation, learning approach and attitude of first aid knowledge, etc. This questionnaire was used to investigate the dentists of medical institutions in various cities in Sichuan province. The survey results was statistical analyzed. RESULTS: There were 245 valid questionnaires. 1) The level of first aid knowledge of dentists was generally lower in Sichuan province. Work department and other departments work experience were the influencing factors of knowledge level of first aid knowledge among dentists. 2) 87.3% of dentists believed that it was very necessary to master the knowledge of first aid, but in the event of an emergency situation, 73.5% of dentists only can find other doctors to guide themselves to help. 3) The most common way to learn first aid knowledge was through work experience and medical school's first aid course. CONCLUSIONS: Dentists should strengthen the learning and training to improve the first aid skill.

Suppression of Tumor Energy Supply by Liposomal Nanoparticle-Mediated Inhibition of Aerobic Glycolysis.

Aerobic glycolysis enables cancer cells to rapidly take up nutrients (e.g., nucleotides, amino acids, and lipids) and incorporate them into the biomass needed to produce a new cell. In contrast to existing chemotherapy/radiotherapy strategies, inhibiting aerobic glycolysis to limit the adenosine 5'-triphosphate (ATP) yield is a highly efficient approach for suppressing tumor cell proliferation. However, most, if not all, current inhibitors of aerobic glycolysis cause significant adverse effects because of their nonspecific delivery and distribution to nondiseased organs, low bioavailability, and a narrow therapeutic window. New strategies to enhance the biosafety and efficacy of these inhibitors are needed for moving them into clinical applications. To address this need, we developed a liposomal nanocarrier functionalized with a well-validated tumor-targeting peptide to specifically deliver the aerobic glycolysis inhibitor 3-bromopyruvate (3-BP) into the tumor tissue. The nanoparticles effectively targeted tumors after systemic administration into tumor-bearing mice and suppressed tumor growth by locally releasing 3-BP to inhibit the ATP production of the tumor cells. No overt side effects were observed in the major organs. This report demonstrates the potential utility of the nanoparticle-enabled delivery of an aerobic glycolysis inhibitor as an anticancer therapeutic agent.

Application of solvent modified PEDOT:PSS to graphene electrodes in organic solar cells.

Graphene has been proposed as a promising transparent conducting electrode material in organic photovoltaic (OPV) solar cells to substitute the widely used indium tin oxide (ITO). Various studies have reported OPV devices with graphene electrodes showing comparable performances to ITO-based OPV cells. However, the fabrication reliability or device yield has not been widely discussed. In our investigation it was found that graphene-based OPVs tend to have much lower device yield than the ITO-based ones if similar fabrication processes are used. One possible reason could be due to the challenge faced in obtaining a uniform coating of PEDOT:PSS hole injection layer (HIL) on graphene. In fact, several attempts have been made to overcome this challenge. In this work, we report a facile method of solvent modification of PEDOT:PSS to achieve a homogeneous coating on graphene. A significant enhancement in the device yield was observed as compared to devices using normal aqueous solution based PEDOT:PSS; nevertheless, it was still only ∼50%. Further improvement was made by adding an additional electron blocking layer (EBL), molybdenum trioxide, after the coating of PEDOT:PSS. The observation in this work calls for further investigation to understand the role played by the HIL or EBL in graphene-based OPV devices.

Transumbilical single-incision laparoscopic fundoplication: a new technique for liver retraction using cyanoacrylate.

BACKGROUND/AIM: Single-incision laparoscopic fundoplication is not widespread because of its technical difficulty. An additional stay suture or retractor is often needed for liver retraction during the procedure. Here, we share our 7 cases to demonstrate the feasibility of transumbilical single-incision laparoscopic fundoplication with a new technique for liver retraction without any stay suture or retractor. PATIENTS AND METHODS: From March 2010 to October 2011, 3 patients with achalasia underwent a transumbilical single-incision laparoscopic Heller-Dor operation, and 4 patients with hiatus hernia underwent transumbilical single-incision laparoscopic hernioplasty and Nissen fundoplication. The procedures were attempted transumbilically by using three rigid trocars (one was 10 mm, and two were 5 mm) inserted through the 2-cm umbilicus incision. Conventional laparoscopic instruments were used. Adequate retraction of the liver was achieved by binding the lateral left lobe of the liver to the diaphragm with cyanoacrylate. RESULTS: The pneumoperitoneal time was 115-170 minutes, and blood loss was 15-50 mL. There were no intra- or postoperative complications. The hospital stay was under 6 days for all patients. The umbilical incision healed well with satisfactory cosmetic effect. CONCLUSIONS: The transumbilical single-incision laparoscopic technique in the treatment of achalaisa and hiatus hernia is feasible for an experienced laparoscope surgeon with excellent cosmetic effect. Cyanoacrylate, when used as described, offers a safe and simple solution to the problem of liver retraction, thus obviating the need for a stay suture or liver retractor.

Organic solar cells with graphene electrodes and vapor printed poly(3,4-ethylenedioxythiophene) as the hole transporting layers.

For the successful integration of graphene as a transparent conducting electrode in organic solar cells, proper energy level alignment at the interface between the graphene and the adjacent organic layer is critical. The role of a hole transporting layer (HTL) thus becomes more significant due to the generally lower work function of graphene compared to ITO. A commonly used HTL material with ITO anodes is poly(3,4-ethylenedioxythiophene) (PEDOT) with poly(styrenesulfonate) (PSS) as the solid-state dopant. However, graphene's hydrophobic surface renders uniform coverage of PEDOT:PSS (aqueous solution) by spin-casting very challenging. Here, we introduce a novel, yet simple, vapor printing method for creating patterned HTL PEDOT layers directly onto the graphene surface. Vapor printing represents the implementation of shadow masking in combination with oxidative chemical vapor deposition (oCVD). The oCVD method was developed for the formation of blanket (i.e., unpatterened) layers of pure PEDOT (i.e., no PSS) with systematically variable work function. In the unmasked regions, vapor printing produces complete, uniform, smooth layers of pure PEDOT over graphene. Graphene electrodes were synthesized under low-pressure chemical vapor deposition (LPCVD) using a copper catalyst. The use of another electron donor material, tetraphenyldibenzoperiflanthene, instead of copper phthalocyanine in the organic solar cells also improves the power conversion efficiency. With the vapor printed HTL, the devices using graphene electrodes yield comparable performances to the ITO reference devices (η(p,LPCVD) = 3.01%, and η(p,ITO) = 3.20%).

Synthesis and characterization of hexagonal boron nitride film as a dielectric layer for graphene devices.

Hexagonal boron nitride (h-BN) is a promising material as a dielectric layer or substrate for two-dimensional electronic devices. In this work, we report the synthesis of large-area h-BN film using atmospheric pressure chemical vapor deposition on a copper foil, followed by Cu etching and transfer to a target substrate. The growth rate of h-BN film at a constant temperature is strongly affected by the concentration of borazine as a precursor and the ambient gas condition such as the ratio of hydrogen and nitrogen. h-BN films with different thicknesses can be achieved by controlling the growth time or tuning the growth conditions. Transmission electron microscope characterization reveals that these h-BN films are polycrystalline, and the c-axis of the crystallites points to different directions. The stoichiometry ratio of boron and nitrogen is close to 1:1, obtained by electron energy loss spectroscopy. The dielectric constant of h-BN film obtained by parallel capacitance measurements (25 µm(2) large areas) is 2-4. These CVD-grown h-BN films were integrated as a dielectric layer in top-gated CVD graphene devices, and the mobility of the CVD graphene device (in the few thousands cm(2)/(V·s) range) remains the same before and after device integration.

Selective molecular transport through intrinsic defects in a single layer of CVD graphene.

We report graphene composite membranes with nominal areas more than 25 mm(2) fabricated by transfer of a single layer of CVD graphene onto a porous polycarbonate substrate. A combination of pressure-driven and diffusive transport measurements provides evidence of size-selective transport of molecules through the membrane, which is attributed to the low-frequency occurrence of intrinsic 1-15 nm diameter pores in the CVD graphene. Our results present the first step toward the realization of practical membranes that use graphene as the selective material.

Solution chemistry of self-assembled graphene nanohybrids for high-performance flexible biosensors.

We report the preparation of free-standing flexible conductive reduced graphene oxide/Nafion (RGON) hybrid films by a solution chemistry that utilizes self-assembly and directional convective-assembly. The hydrophobic backbone of Nafion provided well-defined integrated structures, on micro- and macroscales, for the construction of hybrid materials through self-assembly, while the hydrophilic sulfonate groups enabled highly stable dispersibility ( approximately 0.5 mg/mL) and long-term stability (2 months) for graphene. The geometrically interlocked morphology of RGON produced a high degree of mechanical integrity in the hybrid films, while the interpenetrating network constructed favorable conduction pathways for charge transport. Importantly, the synergistic electrochemical characteristics of RGON were attributed to high conductivity (1176 S/m), facilitated electron transfer (ET), and low interfacial resistance. Consequently, RGON films obtained the excellent figure of merit as electrochemical biosensing platforms for organophosphate (OP) detection, that is, a sensitivity of 10.7 nA/microM, detection limit of 1.37 x 10(-7) M, and response time of <3 s. In addition, the reliability of RGON biosensors was confirmed by a fatigue test of 100 bending cycles. The strategy described here provides insight into the fabrication of graphene and hybrid nanomaterials from a material perspective, as well as the design of biosensor platforms for practical device applications.

Some thoughts on the existence of ion and water channels in highly dense and well-ordered CH3-terminated alkanethiol self-assembled monolayers on gold.

Through extensive and systematic reviewing of literatures, this paper presents some thoughts on the existence of ion and water channels in highly dense and well-ordered CH(3)-terminated alkanethiol self-assembled monolayers (C(n)SH-SAMs) on gold: (1) based on the combinational effect of "the van der Waals interaction between the neighbor hydrocarbon chains", "the framework size of C(n)SH molecule" and "the surface lattice structure of C(n)SH-SAMs on gold", a simple ideal model of the close-packed C(n)SH-SAMs is proposed for the first time. The channel with an appropriate diameter of about 3A ( approximately 3A) existing in SAMs on Au is deduced, which is found large enough for ions and water molecules to permeate; (2) through summarizing the literature reports for various experiments (e.g. scan microscopy techniques and electrochemical methods, etc.), the existence of the ion and water channels ( approximately 3A) in close-packed C(n)SH-SAMs is verified; (3) furthermore, the effect of the ions and water molecules permeation on the studies of the SAMs' electron tunneling process is discussed. This simple ideal model of the close-packed C(n)SH-SAMs established by us may clarify the controversies about the permeation mechanism of ions and water molecules in C(n)SH-SAMs.

Large area, few-layer graphene films on arbitrary substrates by chemical vapor deposition.

In this work we present a low cost and scalable technique, via ambient pressure chemical vapor deposition (CVD) on polycrystalline Ni films, to fabricate large area ( approximately cm2) films of single- to few-layer graphene and to transfer the films to nonspecific substrates. These films consist of regions of 1 to approximately 12 graphene layers. Single- or bilayer regions can be up to 20 mum in lateral size. The films are continuous over the entire area and can be patterned lithographically or by prepatterning the underlying Ni film. The transparency, conductivity, and ambipolar transfer characteristics of the films suggest their potential as another materials candidate for electronics and opto-electronic applications.

Superwetting nanowire membranes for selective absorption.

The construction of nanoporous membranes is of great technological importance for various applications, including catalyst supports, filters for biomolecule purification, environmental remediation and seawater desalination. A major challenge is the scalable fabrication of membranes with the desirable combination of good thermal stability, high selectivity and excellent recyclability. Here we present a self-assembly method for constructing thermally stable, free-standing nanowire membranes that exhibit controlled wetting behaviour ranging from superhydrophilic to superhydrophobic. These membranes can selectively absorb oils up to 20 times the material's weight in preference to water, through a combination of superhydrophobicity and capillary action. Moreover, the nanowires that form the membrane structure can be re-suspended in solutions and subsequently re-form the original paper-like morphology over many cycles. Our results suggest an innovative material that should find practical applications in the removal of organics, particularly in the field of oil spill cleanup.

[A pilot study on relationship of periodontal status, serum level of interleukin-1beta and delivery outcomes in pregnant women].

OBJECTIVE: To evaluate the associations between periodontal conditions, serum level of interleukin-1beta (IL-1beta) and delivery outcomes in pregnant women with a diagnosis of threatened premature labor(TPL). METHODS: Eighty systemically healthy pregnant women were enrolled in the study. The case group was composed of 40 pregnant women hospitalized with the diagnosis of TPL (TPL group) and the control group was composed of 40 normal pregnant women (Non-TPL group). Periodontal examinations included assessments of plaque index (PLI), clinical attachment loss (CAL), probing depth (PD), bleeding index (BI) and the percent of periodontitis sites (PD >3 mm, CAL > or =2 mm). The serum level of IL-1beta was determined using commercially available enzyme-linked immunoassays. RESULTS: (1) Fourteen of forty subjects of TPL group delivered premature labor infants (TPL-TB group), and twenty-six subjects delivered natural labor infants (TPL-PB group). No infants were delivered as premature labor infants in non-TPL group. There were significant differences in gestational age at delivery, birth weight, PLI, percentage of periodontitis sites and IL-1beta levels between the non-TPL group and TPL group or between the TPL-TB group and TPL-PB group (P < 0.05). (Significant negative correlation were observed between the gestational age at delivery and percentage of periodontitis sites as well as serum IL-1beta levels (P < 0.05). And significant positive correlation were observed between percentage of periodontitis site and serum IL-1beta levels (P < 0.05). CONCLUSION: Periodontal inflammation might be one of the pathogenesis of preterm birth.

[Analysis of periodontal status in pregnant women with a diagnosis of threatened premature labor].

PURPOSE: To evaluate the associations between periodontal conditions and delivery outcomes in pregnant women with a diagnosis of threatened premature labor (TPL). METHODS: Eighty systemically healthy pregnant women were enrolled in the study. The case group was composed of 40 pregnant women hospitalized with the diagnosis of TPL and the control group was composed of 40 normal pregnant women. Periodontal examinations included assessments of plaque index (PLI), clinical attachment loss (CAL), probing depth (PD), bleeding index (BI) and the percentage of periodontitis sites (PD > 3 mm, CAL > or = 2mm). The serum level of IL-6 was determined using commercially available enzyme-linked immunoassays (ELISA). The data were analyzed with SPSS11.0 software package for chi2 test, Student's t test and Pearson correlation analysis. RESULTS: 40 subjects were clarified as TPL and 14 as TPL-PB. 26 TPL women subsequently delivered TB infants. No infants were delivered as PB in 40 subjects clarified as non-TPL. There were no significant differences in the mean ages and gestational age at examination between the non-TPL and TPL groups or between the TPL-TB, and TPL-PB groups. There were significant differences in gestational age at delivery and birth weight between the non-TPL and TPL groups or between the TPL-TB, and TPL-PB groups (P < 0.05). The mean PLI, percentage of periodontitis sites and IL-6 levels were significantly higher in the TPL group than those of the non-TPL group. The mean PLI, BI, and percentage of periodontitis sites were significantly higher in the TPL-PB group than those of the TPL-TB group. Significant negative correlations were observed between the gestational age at delivery and percentage of periodontitis sites as well as BI (P < 0.05). CONCLUSION: Periodontal inflammation might be involved in the pathogenesis of preterm birth.

[Associations between periodontal status and delivery outcomes in pregnant women with a diagnosis of threatened premature labor].

OBJECTIVE: To evaluate the association between periodontal conditions and delivery outcomes in pregnant women with a diagnosis of threatened premature labor (TPL). METHODS: Eighty systemically healthy pregnant women were enrolled in the study. Forty of these were pregnant women hospitalized with the diagnosis of TPL, and 40 normal pregnant women served. TPL was control clarified as TPL-PB (14 women) and TPL-TB (26 women) based on the delivery outcomes. No infants were delivered as PB in the control with non-TPL. Periodontal examinations included assessments of plaque index (PLI), clinical attachment loss (CAL), probing depth (PD), bleeding index (BI) and the percentage of periodontitis sites (PD > 3 mm, CAL >or= 2 mm). The serum level of TNF-alpha was determined using commercially available enzyme-linked immunoassays (ELISA). RESULTS: The mean PLI (0.94 +/- 0.05), percentage of periodontitis sites (2.93%) and TNF-alpha levels [14.81 ng/L (13.40 - 15.64 ng/L)] were significantly higher in the TPL group than in the non-TPL group [0.59 +/- 0.03, 1.32% and 11.47 ng/L (10.82 - 12.86) ng/L] (P < 0.001). The mean PLI (0.96 +/- 0.06), BI (2.99 +/- 0.14), percentage of periodontitis sites (3.61%) and TNF-alpha levels [18.35 ng/L (15.47 - 31.94) ng/L] were significantly higher in the TPL-PB group than in the TPL-TB group [0.66 +/- 0.04, 2.76 +/- 0.12, 2.25% and 13.70 ng/L (12.64 - 14.80 ng/L)]. Significant negative correlations were observed between the gestational age at delivery and percentage of periodontitis sites as well as serum TNF-alpha levels (P < 0.05). And significant positive correlations were observed between percentage of periodontitis site and serum TNF-alpha levels (P < 0.05). CONCLUSIONS: Periodontal inflammation might be involved in the pathogenesis of preterm birth.