Effects of lactoferrin and lactoperoxidase-containing food on the oral microbiota of older individuals.

The oral microbiota influences health and disease states. Some gram-negative anaerobic bacteria play important roles in tissue destruction associated with periodontal disease. Lactoferrin (LF) and lactoperoxidase (LPO) are antimicrobial proteins found in saliva; however, their influence on the whole oral microbiota currently remains unknown. In this randomized, double-blinded, placebo-controlled study, the effects of long-term ingestion of LF and LPO-containing tablets on the microbiota of supragingival plaque and tongue coating were assessed. Forty-six older individuals ingested placebo or test tablets after every meal for 8 weeks. The relative abundance of bacterial species was assessed by 16S rRNA gene high-throughput sequencing. Most of the bacterial species in supragingival plaque and tongue coating that exhibited significant decreases in the test group were gram-negative bacteria, including periodontal pathogens. Decreases in the total relative abundance of gram-negative organisms in supragingival plaque and tongue coating correlated with improvements in assessed variables related to oral health, such as oral malodor and plaque accumulation. Furthermore, there was significantly less microbiota diversity in supragingival plaque at 8 weeks in the test group than in the placebo group and low microbiota diversity correlated with improvements in assessed variables related to oral health. These results suggest that LF and LPO-containing tablets promote a shift from a highly diverse and gram-negative-dominated to a gram-positive-dominated community in the microbiota of supragingival plaque and tongue coating. This microbial shift may contribute to improvements in oral health, including oral malodor and state of the gingiva.

Leaching behaviors of dissolved organic matter from face masks revealed by fluorescence EEM combined with FRI and PARAFAC.

Despite numerous studies investigating the occurrence and fate of microplastics, no effort has been devoted toward exploring the characteristics of dissolved organic matter (DOM) leached from face masks mainly made of plastics and additives used in large quantities during the COVID-19 pandemic. By using FTIR, UV-vis, fluorescence EEM coupling with FRI and PARAFAC, and kinetic models of leaching experiments, we explored the leaching behaviors of face mask-derived DOM (FM-DOM) from commonly used face masks including N95, KN95, medical surgical masks, etc. The concentration of FM-DOM increased quickly at early 0-48 h and reached equilibrium at about 48 h measured in terms of dissolved organic carbon and fluorescence intensity. The protein-like materials ranged from 80.32 % to 89.40 % of percentage fluorescence response (Pi,n) were dominant in four types of FM-DOM analyzed by fluorescence EEM-FRI during the leaching experiments from 1 to 360 h. Four fluorescent components were identified, which included tryptophan-like components, tyrosine-like components, microbial protein-like components, and fulvic-like components with fluorescence EEM-PARAFAC models. The multi-order kinetic model (Radj2 0.975-0.999) fitted better than the zero-order and first-order kinetic model (Radj2 0.936-0.982) for all PARAFAC components of FM-DOM based on equations derived by pseudo kinetic models. The leaching rate constants (kn) ranged from 0.058 to 30.938 and the half-life times (T1/2) ranged from 2.73 to 24.87 h for four FM-DOM samples, following the solubility order of fulvic-like components (C4) > microbial protein-like components (C3) > tryptophan-like components (C1) > tyrosine-like components (C2) for FM-DOM from four types of face masks during the leaching experiment from 0 to 360 h. These novel findings will contribute to the understanding of the underappreciated environment impact of face masks in aquatic ecosystems.

A structure-function relationship for the optical modulation of phenyl boronic acid-grafted, polyethylene glycol-wrapped single-walled carbon nanotubes.

Phenyl boronic acids (PBA) are important binding ligands to pendant diols useful for saccharide recognition. The aromatic ring can also function to anchor an otherwise hydrophilic polymer backbone to the surface of hydrophobic graphene or carbon nanotube. In this work, we demonstrate both functions using a homologous series of seven phenyl boronic acids conjugated to a polyethylene glycol, eight-membered, branched polymer (PPEG8) that allows aqueous dispersion of single-walled carbon nanotubes (SWNT) and quenching of the near-infrared fluorescence in response to saccharide binding. We compare the 2-carboxyphenylboronic acid (2CPBA); 3-carboxy- (3CPBA) and 4-carboxy- (4CPBA) phenylboronic acids; N-(4-phenylboronic)succinamic acid (4SCPBA); 5-bromo-3-carboxy- (5B3CPBA), 3-carboxy-5-fluoro- (5F3CPBA), and 3-carboxy-5-nitro- (5N3CPBA) phenylboronic acids, demonstrating a clear link between SWNT photoluminescence quantum yield and boronic acid structure. Surprisingly, quantum yield decreases systematically with both the location of the BA functionality and the inclusion of electron-withdrawing or -donating substituents on the phenyl ring. For three structural isomers (2CPBA, 3CPBA, and 4CPBA), the highest quantum yields were measured for para-substituted PBA (4CPBA), much higher than ortho- (2CPBA) and meta- (3CPBA) substituted PBA, indicating the first such dependence on molecular structure. Electron-withdrawing substituents such as nitro groups on the phenyl ring cause higher quantum yield, while electron-donating groups such as amides and alkyl groups cause a decrease. The solvatochromic shift of up to 10.3 meV was used for each case to estimate polymer surface coverage on an areal basis using a linear dielectric model. Saccharide recognition using the nIR photoluminescence of SWNT is demonstrated, including selectivity toward pentoses such as arabinose, ribose, and xylose to the exclusion of the expected fructose, which has a high selectivity on PBA due to the formation of a tridentate complex between fructose and PBA. This study is the first to conclusively link molecular structure of an adsorbed phase to SWNT optical properties and modulation in a systematic manner.

A method to extract cytokines and matrix metalloproteinases from Schirmer strips and analyze using Luminex.

PURPOSE: The Schirmer's test is commonly used in the clinic for the diagnosis of dry eye disease by measuring tear volume. This report describes a procedure which can be used to recover tears from the Schirmer strip for the measurement of multiple tear cytokines as well as matrix metalloproteinases (MMPs) by Luminex technology. METHODS: Cytokine and MMP recovery was determined by using spiked Schirmer strips presoaked with known cytokines or MMPs prepared in PBS with 1% BSA. In a clinical study, tears were collected from 5 subjects using Schirmer strips. Strips were stored on ice immediately after removal from the subject and stored dry at -20 °C for 16-24 h. Cytokines were extracted from the Schirmer strip in 0.5 M NaCl with 0.5% Tween-20. Concentrations of cytokines and MMPs in collected tear samples were analyzed by Luminex using both a 10-cytokine and a 5-MMP kit. RESULTS: The standard curves for the assay in both the kit assay buffer and extraction buffer were identical for 9 of the 10 cytokines and all 5 MMPs. In the clinical sample all the cytokines (interleukin 1α [IL-1α], IL-1ß, IL-1ra, IL-4, IL-6, IL-8, IL-10, IL-13, monocyte chemotactic protein-1 [MCP-1], and tumor necrosis factor-α [TNF-α]) and 5 MMPs (MMP-1, MMP-2, MMP-7, MMP-9, and MMP-10) tested were detected in at least 50% of the 10 subject samples. Recoveries from extracted Schirmer strips were >60% for 8 of the 10 cytokines and all MMPs. CONCLUSIONS: Numerous cytokines and MMPs were detected in the tear samples collected using the Schirmer strip, including many that have been implicated in ocular surface disease. This procedure may be used to evaluate the cytokine and MMP content in tear samples in clinical studies, especially for the evaluation of dry eye therapeutics. Because the Schirmer test is routine in the assessment of dry eye, this method offers the opportunity to evaluate both the quantity and quality of the tears.

Bionic mechanical design and SLM manufacture of porous Ti6Al4V scaffolds for load-bearing cancellous bone implants.

In order to repair the load-bearing cancellous bone defect of the human lower extremity, the development of a porous scaffold with high porosity, appropriate pore size, low elastic modulus and high fatigue strength has been faced with great challenges. In this study, the Ti6Al4V coaxial scaffolds with five types of beam angles and three types of pore sizes were designed using CAD and fabricated with the use of SLM. The porous characteristics and mechanical properties of scaffolds were investigated systematically. The results show that the porosity of the coaxial scaffolds is 63-69%, and the pore size is 480-700 µm. Meanwihle, the elastic modulus and compressive strength of the coaxial scaffolds were 1.08-1.85 GPa, 40-88 MPa, respectively. Moreover, the fatigue strength of the coaxial scaffolds with 500-40°, 600-40°, 700-40° were 1387, 1110 and 420 MPa, respectively. The pore size and porosity of the coaxial scaffolds in our study satisfied the size requirements for bone cells growth. Meanwhile, the low elastic modulus and high fatigue strength of the scaffolds also met the bio-mechanical bearing requirements of cancellous bone implants. Our study provided a reference for the design of biomimetic cancellous bone implants with good dynamic load-bearing mechanical properties.

The occurrence, severity degree, and associated risk factors of dental fluorosis among the 12-year-old schoolchildren in Jilin, China.

ABSTRACT: This study aims to describe the occurrence, severity degree, and correlated risk factors of dental fluorosis among the 12-year-old schoolchildren of Jilin, China.We conducted a cross-sectional, observational, and descriptive study among 960 12-year-old schoolchildren in Jilin. The Dean index was utilized to evaluate the severity degree of dental fluorosis. A questionnaire was sent to the guardians of children. Community fluorosis index was measured to estimate the importance of enamel fluorosis for the whole population's public health. The logistic regression analysis was also utilized to identify the correlation between fluorotic teeth and the independent variables.Nine hundred sixty children were assessed. Among them, 480 (50%) were female. 30.5% of subjects had dental fluorosis, 7.19% had very mild dental fluorosis, 10.73% experienced mild dental fluorosis, 9.58% suffered moderate dental fluorosis, and 3.02% encountered severe dental fluorosis. The overall community fluorosis index was 0.73. The results of logistic regression showed that schoolchildren who brushed teeth more frequently (OR: 2.012, 95% CI 1.767-2.342), deficiency of parental supervision (OR: 4.219, 95% CI 3.887-4.573), and lived in rural areas (OR: 2.776, 95% CI 2.163-3.489) were more correlated with enamel fluorosis. Moreover, schoolchildren whose mothers or fathers were of high education level (OR: 0.336, 95% CI 0.217-0.413 and 0.346, 95% CI 0.113-0.512) and only child (OR: 0.378, 95% CI 0.213-0.415) were protective factors for dental fluorosis.In the Jilin province of China, the risk indicators for dental fluorosis include rural areas, more frequency of brushing, low educational background of parents, and deficiency of parental supervision.

Multidecadal records of microplastic accumulation in the coastal sediments of the East China Sea.

Microplastics are an emerging hazard in the marine environment, and considered to eventually sink into sediments. An investigation into the long-term variation of microplastic accumulation in sediment cores is essential for understanding the historical trend of this contamination and its response to human activities. In this study, the multidecadal changes of microplastic abundances in two sediment cores from the inner shelf of the East China Sea (ECS) were revealed by two methods, i.e., a visual enumeration method based on scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and a quantitative method based on microplastic-derived carbon (MPC) abundances. The features of microplastics were determined via SEM-EDS and micro-Fourier transform infrared spectroscopy (µ-FTIR). The results reveal a multidecadal increasing trend of microplastic accumulation in the coastal sediments of the ECS since the 1960s, which may be jointly governed by the release of plastic wastes and oceanographic dynamics. Meanwhile, the breakpoint of the exponential growth of microplastics in the ECS occurs in 2000 AD, which well matches the rapid increasing of plastic production and consumption in China. Further, based on the MPC contents in sediments, the influence of microplastics on the quantitative evaluation of carbon storage in the ECS has been examined for the first time, revealing an insignificant (<2% before 2014 AD) but potentially-increasing (6.8% by 2025 AD) contribution of microplastics to carbon burial. Our results may provide the important data for evaluating and mitigating the impact of microplastics on the marine environment.

Fabrication of ultralong and electrically uniform single-walled carbon nanotubes on clean substrates.

We report the controlled growth of ultralong single-wall carbon nanotube (SWNT) arrays using an improved chemical vapor deposition strategy. Using ethanol or methane as the feed gas, monodispersed Fe-Mo as the catalyst, and a superaligned carbon nanotube (CNT) film as the catalyst supporting frame, ultralong CNTs over 18.5 cm long were grown on Si substrates. The growth rate of the CNTs was more than 40 mum/s. No catalyst-related residual material was found on the substrates due to the use of a CNT film as the catalyst supporting frame, facilitating any subsequent fabrication of SWNT-based devices. Electrical transport measurements indicated that the electrical characteristics along a single ultralong SWNT were uniform. We also found that maintaining a spatially homogeneous temperature during the growth process was a critical factor for obtaining constant electrical characteristics along the length of the ultralong SWNTs.

Expression of Dickkopf-related Protein 1 in Patients with Temporomandibular Osteoarthritis after Treatment with Hyaluronic Acid.

We previously reported that the increased expression of Dickkopf-related protein 1 (DKK1) is positively related to vascular endothelial growth factor in the synovial fluid from patients with temporomandibular joint disorders (TMDs). DKK1 is involved in angiogenic activities in the TMD synovium in vitro, but the expression of DKK1 after treatment of TMD-osteoarthritis (TMD-OA) with hyaluronic acid (HA) remains unknown. In this study, we assessed the expression of DKK1 in the synovial fluid of TMD-OA patients before and after treatment with HA via enzyme-linked immunosorbent assay. We also investigated the role of DKK1 in TMD-OA via immunohistochemical staining. The relationship between the expression of DKK1 and the clinicopathological characteristics was determined by Pearson analysis. The results showed that the expression of DKK1 was significantly decreased after treatment with HA. Correlation analyses indicated that the expression of DKK1 in the TMD-OA samples was closely correlated with mouth opening and pain. These findings suggest that DKK1 could play an important role in the pathogenesis and treatment of TMD. Reduction of the pain by HA treatment may be correlated with the decreased expression of DKK1.

Neonatal oral fluid as a transmission route for bifidobacteria to the infant gut immediately after birth.

Bifidobacteria are one of the most abundant bacterial groups in the infant gut microbiota and are closely associated with infant health and can potentially affect health in later life. However, the details regarding the source of bifidobacteria have yet to be completely elucidated. This study aimed to assess neonatal oral fluid (OF) as a transmission route for bifidobacteria to the infant gut during delivery. Neonatal OF and infant feces (IF) were collected immediately and one month after birth from 15 healthy vaginally delivered newborns. Bifidobacterium strains were isolated from OF and IF samples, and the similarity of strains between the OF-IF pairs was evaluated based on the average nucleotide identity (ANI) value. The 16S rRNA gene sequencing results revealed the presence of Bifidobacteriaceae at >1% relative abundance in all OF samples. Bifidobacterium strains were isolated from OF (9/15) and IF (11/15) samples, and those sharing high genomic homology (ANI values >99.5%) between the neonatal OF and IF samples were present in one-third of the OF-IF pairs. The results of this study indicate that viable bifidobacteria are present in neonatal OF and that OF at birth is a possible transmission route of bifidobacteria to the infant gut.

Chondroitin sulfate-polydopamine modified polyethylene terephthalate with extracellular matrix-mimetic immunoregulatory functions for osseointegration.

Optimal integration between the polyethylene terephthalate (PET) graft and host bone is a prerequisite to obtain a satisfactory outcome after graft implantation for ligament reconstruction. Recent studies indicate that complex biosignals including immunoregulation, cell recruitment, and osteogenic differentiation provided by the extracellular matrix (ECM) are conducive to promoting osseointegration. In the present study, a chondroitin sulfate (CS)/polydopamine-modified PET graft was developed to regulate the local immune microenvironment, guide stem cell behavior, and promote new bone formation. We found that CS-modified PET grafts significantly regulated the macrophage phenotype switching from M1 to M2 and promoted the expression of pro-repair cytokines including interleukin (IL)-4, IL-10 and transforming growth factor (TGF)-ß1. Moreover, the immunoregulatory function of CS-modified PET guided stem cell behaviors, including recruitment, adhesion, and proliferation, and enhanced the osteogenic differentiation of stem cells. In vivo experiments confirmed that CS-modified PET switched the local immune microenvironment status from pro-inflammatory to anti-inflammatory, up-regulated osteogenic marker expression, and promoted the bone regeneration process, so as to achieve graft-bone osseointegration. These results indicate that an ECM-biomimetic immunoregulatory coating is an effective approach to promote graft integration. This study proposes an effective strategy for an artificial graft to achieve graft-bone osseointegration through immunoregulatory osteogenesis.

Study on biocompatibility, tribological property and wear debris characterization of ultra-low-wear polyethylene as artificial joint materials.

Ultra-low-wear polyethylene (ULWPE) is a new type polyethylene made by experts who are from China petrochemical research institute, which is easy to process and implant. Preliminary test showed it was more resistant to wear than that of Ultra-high-molecular weight polyethylene (UHMWPE). The purpose of the research is to study biocompatibility, bio-tribological properties and debris characterization of ULWPE. Cytotoxicity test, hemolysis test, acute/chronic toxicity and muscular implantation test were conducted according to national standard GB/T-16886/ISO-10993 for evaluation requirements of medical surgical implants. We obtained that this novel material had good biocompatibility and biological safety. The wear performance of ULWPE and UHMWPE was evaluated in a pin-on-disc (POD) wear tester within two million cycles and a knee wear simulator within six million cycles. We found that the ULWPE was higher abrasion resistance than the UHMWPE, the wear rate of ULWPE by POD test and knee wear simulator was 0.4 mg/106cycles and (16.9 ±â€¯1.8)mg/106cycles respectively, while that of UHMWPE was 1.8 mg/106cycles and (24.6 ±â€¯2.4)mg/106cycles. The morphology of wear debris is also an important factor to evaluate artificial joint materials, this study showed that the ULWPE wear debris gotten from the simulator had various different shapes, including spherical, block, tear, etc. The morphology of worn surface and wear debris analysis showed that wear mechanisms of ULWPE were adhesion wear, abrasive wear and fatigue wear and other wear forms, which were consistent with that of UHMWPE. Thus we conclude that ULWPE is expected to be a lifetime implantation of artificial joint.

Hydrothermal assembly, structures, topologies, luminescence, and magnetism of a novel series of coordination polymers driven by a trifunctional nicotinic acid building block.

In this work, a trifunctional N,O-building block, 5-(4-carboxyphenoxy)nicotinic acid (H2cpna), that combines three distinct types of functional groups (COOH, N-pyridyl, and O-ether) was used for the hydrothermal assembly of thirteen new coordination compounds: [Co(µ3-Hcpna)2]n (1), [Mn(µ4-cpna)(H2O)]n (2), [Mn(µ4-cpna)(H2O)2]n (3), [Mn(µ-cpna)(2,2'-bipy)(H2O)2]n (4), {[Ni(µ3-cpna)(2,2'-bipy)(H2O)]2·H2O}n (5), {[Cd(µ3-cpna)(2,2'-bipy)]·2H2O}n (6), [Zn2(µ-cpna)2(2,2'-bipy)2] (7), [Cu(µ-cpna)(2,2'-bipy)(H2O)]n (8), {[Mn(µ-cpna)(phen)2]·6H2O}n (9), {[Ni(µ3-cpna)(phen)(H2O)]·H2O}n (10), [Zn2(µ-cpna)2(phen)2] (11), {[Pb(µ3-cpna)(phen)]·H2O}n (12), and [Ni(µ3-cpna)(4,4'-bipy)0.5(H2O)]n (13). These products were synthesized from the corresponding metal(ii) chlorides, H2cpna, NaOH, and optional N-donor supporting ligands or templates {bis(4-pyridyl)amine (bpa), 2,2'-bipyridine (2,2'-bipy), 4,4'-bipyridine (4,4'-bipy), or 1,10-phenanthroline (phen)}. Products 1-13 were characterized in the solid state by standard methods, including elemental and thermogravimetric analysis (TGA), IR spectroscopy, and powder (PXRD) and single-crystal X-ray diffraction. The structures of 1-13 feature distinct structural types, namely the 3D metal-organic frameworks (MOFs 1-3), the 2D coordination polymers (5, 6, 10, 12, and 13), the 1D coordination polymers (4, 8, and 9), and the 0D discrete cyclic dimers (7 and 11). Such a wide structural diversity of 1-13 is driven by various factors, including the type of the metal(ii) node, the deprotonation degree of H2cpna, and/or the type of supporting ligand or template. Notably, an addition of bpa can tune the structure of MOF 3 by the template effect. Topological classification of underlying metal-organic networks was performed, leading to several distinct topological nets: rtl (in 1), hxg-d-4-C2/m (in 2), sra (in 3), 2C1 (in 4, 8 and 9), fes (in 5, 10, and 12), hcb (in 6), and 3,4L83 (in 13). The magnetic behavior of 1-5, 8-10, and 13 was studied and theoretically modeled, disclosing antiferromagnetic interactions. The luminescence behavior of 6, 7, 11, and 12 was also investigated.

Risk factors for relapse of middle-stage squamous cell carcinoma of the submandibular region and floor of mouth: the importance of en bloc resection.

Our aim was to investigate retrospectively the rate of recurrence in the intervening region for middle-stage squamous cell carcinoma (SCC) of the tongue and identify the factors that predict relapse and prognosis. A total of 204 patients were included, 96 in the en bloc group and 108 in the control group. The groups were comparable. Two patients in the en bloc group (2%) and 12 in the control group (11%) developed recurrences in the intervening region. Kaplan-Meier analysis showed a reduction in the 5-year disease-specific survival once a recurrence had developed after the primary operation (77% compared with 14%, p<0.001). The en bloc group developed significantly fewer recurrences (2%) than the control group (11%) during the five years; p=0.037), and also had better 5-year disease-specific survival (80% compared with 66%, p=0.04). Cox's multivariate regression indicated that the pathological nodal status (p=0.016) and surgical technique (p=0.037) were independent predictive factors for the 5-year recurrence rate, as well as of 5-year disease-specific survival (p=0.001 and p=0.050, respectively). Recurrence in the intervening region is a negative prognostic factor for these patients, and we recommend en bloc resection as the management of choice for middle-stage SCC of the tongue.

Electrochemical study of a new methylene blue/silicon oxide nanocomposition mediator and its application for stable biosensor of hydrogen peroxide.

A novel organic-inorganic nanocomposite of methylene blue (MB) and silicon oxide was synthesized and characterized by TEM, FTIR, and UV-vis. The as-prepared material was able to transfer the electron of the MB to electrode and was different from other SiO2 spheres structurally. It can be used as mediator to construct a biosensor with horseradish peroxidase (HRP) coimmobilized in the gelatine matrix and cross-linked with formaldehyde. The resulting biosensor exhibited fast amperometric response and good stability to hydrogen peroxide (H2O2). The linear range for H2O2 determination was from 1 x 10(-5) to 1.2 x 10(-3) M, with a detection limit of 4 x 10(-6) M based on S/N = 3. Moreover, the lifetime is more than 3 months under dry conditions at 4 degrees C.

[Effects of gas composition and pressure on the intensity and quality of the plasma induced by a high-energy neodymium glass laser].

In this experiment, the effects of gas composition and pressure on the intensity and quality of the plasma induced by a high-energy neodymium glass laser were studied. The experimental results show that the spectral intensity of the plasma in the argon atmosphere is stronger than that in the air when the pressure is the same. For the steel alloy sample, the intensities of the emission spectrum reach the maximum values when the argon pressure is 0.8 x 10(5) Pa. The self-absorption phenomena of Al II 308.22 and Al II 309.27 nm lines strengthen with the increase of the pressure, and even serious self-reversal appears when the pressure is (0.8-0.9) x 10(5) Pa. The temperature of plasma also raises with the increase of the pressure. When the argon pressure is 0.93 x 10(5) Pa, t h e temperature is about 1500 K higher than that when the argon pressure is about 0.43 x 10(5) Pa.

[Study on analytic precision of laser microemission spectral analysis in argon atmosphere at reduced pressure].

According to mathematic statistics, data for laser microemission spectroscopic analysis were selected, which were collected with the use of CCD (charge-coupled device) in arg on atmosphere at reduced pressure. By selection, the effects of some factors, such as the difference of bore ablated on the sample surface by the laser, the distribution nonuniformity of element in the sample, and the fluctuation of output energy of the laser, etc. were reduced. The method that improves analytic precision of laser microemission spectroscopic analysis was studied. And quantitative analysis of Cu, Zn and Mg in aluminum alloy standard samples was performed, using the Cu (I) line at 324.7 nm, the Zn (I) line at 334.5 nm, and the Mg (I) line at 383.8 nm. The results show that the RSDs of relative intensity of the spectral lines of Cu, Zn, Mg are 1.80%, 4.35% and 6.29% respectively, and the RSDs of quantitative analysis of them are 10.1%, 6.98% and 8.17% respectively. The relative errors of the average of analysis of them are -3.76%, 3.62% and -1.62% respectively.

[Study on the emission spectra of aluminum plasma induced by high energy laser].

The intensities of emission spectra of laser-induced alloy aluminum plasma, with the use of a neodymium glass laser (laser pulse energy is about 25 J), were experimentally studied in argon atmosphere. The effects of atmosphere pressure, height from the observed location of the plasma to the sample surface, operating voltage, and power density of the laser on the signal intensities of emission spectra were discussed. Experimental results showed that the intensities of emission spectra are strongest under 88 kPa of gas pressure. With the increase of the height from the observed location of the plasma to the sample surface, the intensities of emission spectra decrease clearly. At the pressure of 88 kPa and the height of 1.5-2 mm, the emission spectra have maximum intensities. In addition, the spectral line intensities are enhanced significantly with the increase of operating voltage and power density.

Adenoid cystic carcinoma in the maxillary gingiva: a case report and immunohistochemical study.

Gingival adenoid cystic carcinoma (ACC) is a rare malignancy. We describe the diagnosis and treatment of a 43 year-old woman who presented with a persistent oral ulcer for approximately 1 year, and subsequent pain in the left posterior maxillary region. Clinical examination revealed an ulcer in the left upper molar gingiva, with swelling in the region from the second premolar to the third molar. X-ray images demonstrated the involvement of the maxillary alveolar bone. The histopathological and immunohistochemical features were diagnostic of ACC. ACC is often presented as a gingival lesion; thus, it may easily be neglected by patients. The identification of this tumor using specific pathological analyses prevents misdiagnosis and enables clinicians to determine the appropriate treatment. In this case, no recurrence or distant metastasis was observed after 2 years of follow-up.

Reduction-responsive drug delivery based on mesoporous silica nanoparticle core with crosslinked poly(acrylic acid) shell.

A novel reduction-responsive drug delivery system was successfully constructed with mesoporous silica nanoparticle (MSN) core as a drug carrier and poly(acrylic acid) (PAA) shell crosslinked by disulfide linkages as a drug release switcher. To keep the pore structure of MSN intact, PAA was covalently attached to the exterior surface of MSN before removing structure-template via radical polymerization. After removing structure-template and loading doxorubicin (DOX), the PAA shell was crosslinked by cystamine dihydrochloride through amidation reaction. The loading content and the entrapment efficiency of DOX could reach up to 40.2% and 80.4%, respectively. Because that the dissociation of disulfide linkage is reduction-responsive, the release behavior of DOX could be controlled by varying the concentration of reductant, and the release rate was 49.4% after 24h with the existence of 2 mM glutathione (simulated environment of cancer cells), about three times higher than that of without glutathione (corresponding to normal human cells), which was only 16.9%. The in vitro cell assays demonstrated that the disulfide linkages crosslinked MSN-PAA (MSN-PAA-crosslinked) was highly biocompatible and suitable to use as drug carrier, and the DOX loaded MSN-PAA-crosslinked showed remarkable cytotoxicity to HeLa cells (human cancer cells), and relatively lower cytotoxicity to 293 cells (human normal cells). These results imply that the MSN-PAA-crosslinked is a promising platform to construct reduction-responsive controlled drug delivery system for cancer therapy.