Peutz-Jeghers syndrome without STK11 mutation may correlate with less severe clinical manifestations in Chinese patients.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is an autosomal dominant genetic disease with skin mucosal pigment spots and gastrointestinal (GI) multiple hamartoma polyps as clinical characteristics. At present, it is considered that the germline mutation of STK11 gene is the genetic cause of PJS. However, not all PJS patients can be detected STK11 germline mutations. The specific clinical characteristics of these PJS patients without STK11 mutation is an interesting clinical question. Or, like wild type GI stromal tumor, whether these PJS without STK11 mutation are also called PJS is worth discussing. Therefore, we designed the study to understand the clinical characteristics of these PJS patients without STK11 mutation. AIM: To investigates whether PJS patients with known STK11 mutations have a more severe spectrum of clinical phenotypes compared to those without. METHODS: A total of 92 patients with PJS admitted to the Air Force Medical Center from 2010 to 2022 were randomly selected for study. Genomic DNA samples were extracted from peripheral blood samples, and pathogenic germline mutations of STK11 were detected by high-throughput next-generation gene sequencing. Clinical-pathologic manifestations of patients with and without STK11/LKB1 mutations were compared. RESULTS: STK11 germline mutations were observed in 73 patients with PJS. Among 19 patients with no detectable STK11 mutations, six had no pathogenic germline mutations of other genes, while 13 had other genetic mutations. Compared with PJS patients with STK11 mutations, those without tended to be older at the age of initial treatment, age of first intussusception and age of initial surgery. They also had a lower number of total hospitalizations relating to intussusception or intestinal obstruction, and a lower load of small intestine polyps. CONCLUSION: PJS patients without STK11 mutations might have less severe clinical-pathologic manifestations than those with.

Clinical features, diagnosis, and treatment of Peutz-Jeghers syndrome: Experience with 566 Chinese cases.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is a clinically rare disease with pigmented spots on the lips and mucous membranes and extremities, scattered gastrointestinal polyps, and susceptibility to tumors as clinical manifestations. Effective preventive and curative methods are still lacking. Here we summarize our experience with 566 Chinese patients with PJS from a Chinese medical center with regard to the clinical features, diagnosis, and treatment. AIM: To explore the clinical features, diagnosis, and treatment of PJS in a Chinese medical center. METHODS: The diagnosis and treatment information of 566 cases of PJS admitted to the Air Force Medical Center from January 1994 to October 2022 was summarized. A clinical database was established covering age, gender, ethnicity, family history, age at first treatment, time and sequence of appearance of mucocutaneous pigmentation, polyp distribution, quantity, and diameter, frequency of hospitalization, frequency of surgical operations, etc. The clinical data was retrospectively analyzed using SPSS 26.0 software, with P < 0.05 considered statistically significant. RESULTS: Of all the patients included, 55.3% were male and 44.7% were female. Median time to the appearance of mucocutaneous pigmentation was 2 years, and median time from the appearance of mucocutaneous pigmentation to the occurrence of abdominal symptoms was 10 years. The vast majority (92.2%) of patients underwent small bowel endoscopy and treatment, with 2.3% having serious complications. There was a statistically significant difference in the number of enteroscopies between patients with and without canceration (P = 0.004, Z = -2.882); 71.2% of patients underwent surgical operation, 75.6% of patients underwent surgical operation before the age of 35 years, and there was a statistically significant difference in the frequency of surgical operations between patients with and without cancer (P = 0.000, Z = -5.127). At 40 years of age, the cumulative risk of intussusception in PJS was approximately 72.0%, and at 50 years, the cumulative risk of intussusception in PJS was approximately 89.6%. At 50 years of age, the cumulative risk of cancer in PJS was approximately 49.3%, and at 60 years of age, the cumulative risk of cancer in PJS was approximately 71.7%. CONCLUSION: The risk of intussusception and cancer of PJS polyps increases with age. PJS patients ≥ 10 years old should undergo annual enteroscopy. Endoscopic treatment has a good safety profile and can reduce the occurrence of polyps intussusception and cancer. Surgery should be conducted to protect the gastrointestinal system by removing polyps.

Issues in deep peak regulation for circulating fluidized bed combustion: Variation of NOx emissions with boiler load.

In order to improve the consumption of renewable energies, certain amounts of circulating fluidized bed (CFB) boiler units should assume the task of deep peak regulation. However, the effect of CFB boiler load on pollutant emissions such as NOx still needs to be clarified. In this paper, the NOx emission characteristics of two industrial-scale CFB boilers within a wide load range (35%-100%) were further analyzed by using a comprehensive one-dimensional, two-phase CFB mathematical model. Simulation results reveal that, when the load ratio decreases, the NOx emission decreases first and then increases. The non-monotonic variation trend is also confirmed by the operational data collected from the SC-350 boiler. However, for different boilers, the load ratio corresponding to the turning point of NOx emission may be different, e.g., for the 135 MWe super high steam pressure boiler, it is about 40%, while for the 350 MWe supercritical boiler is 50%. On the one hand, the decrease in boiler load leads to a decline in the furnace temperature, which contributes to reducing NOx emission due to the decrease of volatile yields, the lower conversion rate of Vol-N to NOx, and the enhancement of the overall NO reduction on chars. On the other hand, at low loads, the excess air coefficient is generally set to high values, and air staging is weakened, resulting in adverse effects on the NOx emission control. In addition, when the CFB boiler operates at low loads, the solid circulation loop performance usually worsens, and the heat loss caused by incomplete combustion may increase. This study points out that high NOx emission is an unavoidable issue in the process of deep peak regulation for CFB boilers.

Feasibility Study of Grinding Circulating Fluidized Bed Ash as Cement Admixture.

With the widespread application of circulating fluidized bed (CFB) combustion technology, the popularity of CFB ash (CFBA) has increased dramatically and its production and large-scale utilization have become increasingly important. In the context of carbon neutrality peaking, using CFBA as a cement admixture as an effective method of resource utilization not only reduces the pressures caused by carbon emissions in the cement industry but also solves the environmental problems caused by CFBA depositing. However, the formation conditions of CFBA are worse than those of traditional pulverized coal boilers. CFB ash is the combustion product of coal at 850 °C-950 °C, and the characteristics of CFBA usually include a loose and porous structure with many amorphous substances. Furthermore, it has the disadvantages of large particle size, high water-demand ratio, and low activity index when it is directly used as a cement admixture. In this study, CFBA (including fly ash (CFBFA) and bottom ash (CFBBA)) produced by a CFB boiler without furnace desulfurization with limestone was used as a cement admixture material, and the effect of grinding on the fineness, water-demand ratio, and activity index of CFBA were studied. The experimental results showed that the grinding effect could significantly reduce the fineness and water-demand ratio of CFBA as a cement mixture and improve the activity index. With the increase in the grinding time, the water-demand ratio of CFBA first decreased and then increased. CFBBA ground for 10 min and CFBFA ground for 4 min can reduce the water-demand ratio of CFBA by up to 105% and increase the compressive strength of 28-day-old CFBA cement by 7.05%. The grinding process can ensure that CFBA meets the Chinese standards for a cement admixture and realize the resource utilization of CFBA.

Diffuse invasive signet ring cell carcinoma in total colorectum caused by ulcerative colitis: A case report and review of literature.

BACKGROUND: Diffuse invasive signet ring cell carcinoma of the colorectum is extremely rare clinically. This type of colorectal cancer has certain clinical, pathological and biological characteristics that are different from ordinary colorectal cancer. CASE SUMMARY: A 31-year-old young woman was admitted to the hospital for nearly 1 wk due to recurrent symptoms of mucopurulent bloody stools and abdominal distension. Preoperative colonoscopy showed a ring-shaped intestinal wall mass 10 cm from the rectum to the anus. Three pieces of tumor tissue were removed for examination. The pathological results showed rectal mucinous adenocarcinoma. The patient underwent laparoscopic exploration under general anesthesia, and then laparoscopic total colorectal resection, ileal pouch-anal anastomosis and ileostomy were performed. The patient was switched to a FOLFOX + cetuximab regimen. After the fifth cycle, the patient was unable to tolerate further treatment due to tumor progression and multiple organ dysfunction, and died at the end of May 2020. Overall survival was 7 mo. CONCLUSION: Carcinogenesis of ulcerative colitis is different from sporadic colon cancer, and the overall prognosis is extremely poor.

Detection and analysis of common pathogenic germline mutations in Peutz-Jeghers syndrome.

BACKGROUND: Different types of pathogenic mutations may produce different clinical phenotypes, but a correlation between Peutz-Jeghers syndrome (PJS) genotype and clinical phenotype has not been found. Not all patients with PJS have detectable mutations of the STK11/LKB1 gene, what is the genetic basis of clinical phenotypic heterogeneity of PJS? Do PJS cases without STK11/LKB1 mutations have other pathogenic genes? Those are clinical problems that perplex doctors. AIM: The aim was to investigate the specific gene mutation of PJS, and the correlation between the genotype and clinical phenotype of PJS. METHODS: A total of 24 patients with PJS admitted to the Air Force Medical Center, PLA (formerly the Air Force General Hospital, PLA) from November 1994 to January 2020 were randomly selected for inclusion in the study. One hundred thirty-nine common hereditary tumor-related genes including STK11/LKB1 were screened and analyzed for pathogenic germline mutations by high-throughput next-generation sequencing (NGS). The mutation status of the genes and their relationship with clinical phenotypes of PJS were explored. RESULTS: Twenty of the 24 PJS patients in this group (83.3%) had STK11/LKB1 gene mutations, 90% of which were pathogenic mutations, and ten had new mutation sites. Pathogenic mutations in exon 7 of STK11/LKB1 gene were significantly lower than in other exons. Truncation mutations are more common in exons 1 and 4 of STK11/LKB1, and their pathogenicity was significantly higher than that of missense mutations. We also found SLX4 gene mutations in PJS patients. CONCLUSION: PJS has a relatively complicated genetic background. Changes in the sites responsible for coding functional proteins in exon 1 and exon 4 of STK11/LKB1 may be one of the main causes of PJS. Mutation of the SLX4 gene may be a cause of genetic heterogeneity in PJS.

K2CO3-Impregnated Al/Si Aerogel Prepared by Ambient Pressure Drying for CO2 Capture: Synthesis, Characterization and Adsorption Characteristics.

A new potassium-based adsorbent for CO2 capture with Al aerogel used as support is proposed in this work. The adsorbents with different surface modifiers (tetraethyl orthosilicate (TEOS) and trimethyl chlorosilane (TMCS)) and different K2CO3 loadings (10%, 20%, 30% and 40%) were prepared by sol-gel and iso-volume impregnation processes with ambient pressure drying. The CO2 adsorption performance of the adsorbents were tested by a fixed-bed reactor, and their adsorption mechanisms were studied by scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and X-ray fluorescence spectrometry (XRF). Furthermore, the adsorption kinetics and the cycling performance were investigated. The results show that using TEOS to modify the wet gel can introduce SiO2 to increase the strength of the skeleton. On the basis of TEOS modification, TMCS can further modify -OH, thus effectively avoiding the destruction of aerogel structure during ambient drying and K2CO3 impregnation. In this work, the specific surface area and specific pore volume of Al aerogel modified by TEOS + TMCS are up to 635.32 cm2/g and 2.43 cm3/g, respectively. The aerogels without modification (Al-B), TEOS modification (Al/Si) and TEOS + TMCS modification (Al/Si-TMCS) showed the best CO2 adsorption performance at 20%, 30% and 30% K2CO3 loading, respectively. In particular, the CO2 adsorption capacity and K2CO3 utilization rate of Al/Si-TMCS-30K are as high as 2.36 mmol/g and 93.2% at 70 degrees Celsius (°C). Avrami's fractional order kinetic model can well fit the CO2 adsorption process of potassium-based adsorbents. Al-B-20K has a higher apparent activation energy and a lower adsorption rate during the adsorption process. After 15 adsorption-regeneration cycles, Al/Si-TMCS-30K maintain a stable CO2 adsorption capacity and framework structure, while the microstructure of Al/Si-30K is destroyed, resulting in a decrease in its adsorption capacity by nearly 30%. This work provides key data for the application of Al aerogel in the field of potassium-based adsorbent for CO2 capture.

The Different Effects of Organic Amines on Synthetic Metal Phosphites/Phosphates.

Four metal phosphites/phosphates crystal materials C8N4H34Al2P4O18 (1), C3N2H17GaP2O8 (2), H5In2P3O10 (3), and H9In2P3O13 (4) have been solvothermally synthesized by organic amines in the presence of mixed solvents. Structural analyses indicate that compound 1 and 2 show one-dimensional (1D) chain structures; compound 3 and 4 are three-dimensional (3D) inorganic open-framework indium phosphites. Organic amines show different mechanisms in the four compounds. The 2,2'-bipyridine organic amine acts as a template source and it breaks down small molecules, which enter into the structure of compound 1. For compound 2, 1,2-propanediamine has a role as protonated template and it forms a hydrogen bond with the inorganic skeleton structure. As for compound 3 and 4 without the organic template, the benzylamine and 2,2'-bipyridine mainly serve as structure-directing agent. Especially, compound 3 has an odd seven-ring channel, and compound 4 contains 3D intersecting six-ring, eight-ring, and 10-ring channels. X-ray diffraction (XRD), scanning electron microscopy (SEM), CHN, inductive coupled plasma (ICP), Infrared (IR), and thermal gravimetric (TG) analyze the four compounds.

Increased Inhibition Effect of Antrodin C from the Stout Camphor Medicinal Mushroom, Taiwanofungus camphoratus (Agaricomycetes), on A549 through Crosstalk between Apoptosis and Autophagy.

Antrodin C was obtained from Taiwanofungus camphoratus mycelia. The inhibition effect of antrodin C on A549 lung adenocarcinoma cells was evaluated by plate clone formation, wound healing, cell cycle, activated caspase-3, Bax, P53, Bcl-2, and RAPR activities as well as reactive oxygen species release. Plate clone formation assay revealed that antrodin C could significantly inhibit the viability of A549 cells in vitro. Wound healing assay revealed that cell migration was inhibited by exposure to antrodin C at concentrations of 50 and 80 µg/mL. Flow cytometry revealed that antrodin C increased the percentages of cells in the G0/G1 phase at concentrations of 50 and 80 µg/mL and the apoptosis was related to upregulation of caspase-3, Bax, P53 expression, downregulation of Bcl-2, RAPR expression, and the release of reactive oxygen species in the A549 cells. CQ or RAPA could significantly promote or inhibit the inhibition effect on A549 proliferation induced by antrodin C, which suggests that the autophagy played a cytoprotective role on inhibition proliferation of A549 induced by antrodin C. These results indicated that the combination of pro-apoptosis agents and anti-autophagy agents may be a useful strategy in enhancing the anticancer efficacy in non-small cell lung cancer.

Effects of the Limestone Particle Size on the Sulfation Reactivity at Low SO2 Concentrations Using a LC-TGA.

Limestone particle size has a crucial influence on SO2 capture efficiency, however there are few studies on the sulfation reactivity, which covers a broad range of particle sizes at low SO2 concentrations. In this paper, a large-capacity thermogravimetric analyzer (LC-TGA) was developed to obtain the sulfur removal reaction rate under a wide range of particle sizes (3 µm-600 µm) and SO2 concentrations (250 ppm-2000 ppm), and then compared with the results of a traditional fixed bed reactor and a commercial TGA. The experimental results showed that the LC-TGA can well eliminate the external mass transfer and obtain a better measurement performance. Both the final conversion and the reaction rate reduced with the decreasing of SO2 concentration, but ultrafine limestone particles still showed the good sulfation reactivity even at 250 ppm SO2. An empirical sulfation model was established based on the experimental results, which can well predict the sulfation process of different limestone particle sizes at low SO2 concentrations. The model parameters have a strong negative correlation against the particle size, and the fit of the reaction order of SO2 was found to be about 0.6. The model form is very simple to incorporate it into available fluidized bed combustion models to predict SO2 emission.

Numerical Assessment on Rotation Effect of the Stagnation Surface on Nanoparticle Deposition in Flame Synthesis.

The effect of rotation of the stagnation surface on the nanoparticle deposition in the flame stabilizing on a rotating surface (FSRS) configuration was numerically assessed using CFD method. The deposition properties including particle trajectories, deposition time, temperature and surrounding O2 concentration between the flame and stagnation surface were examined. The results revealed that although flame position is insensitive to the surface rotation, the temperature and velocity fields are remarkably affected, and the deposition properties become asymmetric along the burner centerline when the surface rotates at a fast speed (rotational speed ω ≥ 300 rpm). Particles moving on the windward side have similar deposition properties when the surface rotates slowly, but the off-center particles on the leeward side have remarkable longer deposition time, lower deposition temperature, and lower surrounding O2 concentration, and they even never deposit on the surface when the surface rotates at a high speed. The rotation effect of the stagnation surface can be quantitatively described by an analogous Karlovitz number (Ka'), which is defined as the ratio of characteristic residence time of moving surface to the aerodynamics time induced by flame stretch. For high quality semiconducting metal oxide (SMO) films, it is suggested that Ka' ≥ 1 should be kept.

Antrodin C, an NADPH Dependent Metabolism, Encourages Crosstalk between Autophagy and Apoptosis in Lung Carcinoma Cells by Use of an AMPK Inhibition-Independent Blockade of the Akt/mTOR Pathway.

The current study aims to explore the possible anti-lung carcinoma activity of ADC as well as the underlying mechanisms by which ADC exerts its actions in NSCLC. Findings showed that ADC potently inhibited the viability of SPCA-1, induced apoptosis triggered by ROS, and arrested the cell cycle at the G2/M phase via a P53 signaling pathway. Interestingly, phenomena such as autophagosomes accumulation, conversion of the LC3-I to LC3-II, etc., indicated that autophagy could be activated by ADC. The blockage of autophagy-augmented ADC induced inhibition of cell proliferation, while autophagy activation restored cell death, indicating that autophagy had a protective effect against cell death which was induced by ADC treatment. Meanwhile, ADC treatment suppressed both the Akt/mTOR and AMPK signaling pathways. The joint action of both ADC and the autophagy inhibitor significantly increased the death of SPCA-1. An in vitro phase I metabolic stability assay showed that ADC was highly metabolized in SD rat liver microsomes and moderately metabolized in human liver microsomes, which will assist in predicting the outcomes of clinical pharmacokinetics and toxicity studies. These findings imply that blocking the Akt/mTOR signaling pathway, which was independent of AMPK inhibition, could activate ADC-induced protective autophagy in non-small-cell lung cancer cells.

Compound of Stout Camphor Medicinal Mushroom, Taiwanofungus camphoratus (Agaricomycetes), Induces Protective Autophagy in SPCA-1 Cells through AMPK Inhibition-Independent Blockade of the Akt/mTOR Pathway.

Our previous study showed that By-1, a maleimide derivative isolated from Taiwanofungus camphoratus, could induce reactive oxygen species-triggered apoptosis and G2 cell cycle arrest through a caspase-dependent pathway and also induced protective autophagy in human lung cancer SPCA-1 cells. Here, we further examined the autophagy flux and detected related proteins by Western blot analysis and fluorescence activated cell sorting, and we sought to find the exact role and underlying pathway of autophagy in SPCA-1 cells. Our results showed that By-1 treatment activated autophagy flux in SPCA-1 cells, which further confirmed that autophagy was induced by By-1 treatment in our previous study. Autophagy activator rapamycin restored cell death from By-1 treatment (21.32%) and verified that autophagy played a protective role in By-l-treated cells. Meanwhile, By-1 treatment suppressed the Akt-mammalian target of rapamycin (mTOR) pathway and the AMP-activated protein kinase (AMPK) pathway. Taken together, these findings indicate that By-1 induced protective autophagy in SPCA-1 cells through AMPK inhibition-independent blockade of the Akt/mTOR pathway.

Must Peutz-Jeghers syndrome patients have the LKB1/STK11 gene mutation? A case report and review of the literature.

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disease, which is characterized by mucocutaneous pigmentation and multiple gastrointestinal hamartoma polyps. The germline mutation of LKB1/STK11 gene on chromosome 19p13.3 is considered to be the hereditary cause of PJS. However, must a patient with PJS have the LKB1/STK11 gene mutation? We here report a case of a male patient who had typical manifestations of PJS and a definite family history, but did not have LKB1/STK11 gene mutation. By means of high-throughput sequencing technology, only mutations in APC gene (c.6662T > C: p.Met2221Thr) and MSH6 gene (c.3488A > T: p.Glu1163Val) were detected. The missense mutations in APC and MSH6 gene may lead to abnormalities in structure and function of their expression products, and may result in the occurrence of PJS. This study suggests that some other genetic disorders may cause PJS besides LKB1/STK11 gene mutation.

Autophagy Inhibition Enhances SPCA-1 Cell Proliferation Inhibition Induced by By-1 from the Stout Camphor Medicinal Mushroom, Taiwanofungus camphoratus (Agaricomycetes).

Taiwanofungus camphoratus has been reported to have antitumor effects against various cancer cells. The aim of this study was to investigate the direct inhibitory effect of By-1 (3-isobutyl-l-methoxy-4-[4'-(3-methylbut-2-enyloxy)phenyl]-1H-pyrrole-2,5-dione), a compound from spent broth from submerged cultures of T. camphoratus, on human lung adenocarcinoma cells and to determine the molecular mechanism underlying this effect. The growth-inhibitory assay and colony formation assay showed that cell viability was significantly decreased. A By-1 concentration of 300 µmol/L caused 73.55% cell death and at a concentration of 240 µmol/L led to a 58% reduction in the number of colonies. The wound-healing assay showed that the distance of migration was 0.3 times shorter than that of untreated cells. Flow cytometry revealed that By-1 could suppress DNA synthesis, cause cell cycle arrest at the S phase, and induce apoptosis in a reactive oxygen species-dependent manner. Furthermore, the expression of caspase-3 and P53 was 4 times higher than that in untreated cells, and the antiapoptotic protein Bcl-2 was decreased 2 times compared with the protein in untreated cells. It is interesting to note that apoptosis and autophagy were both induced during treatment with By-1, and autophagy inhibition decreased cell proliferation. By-1 potently inhibited the growth of SPCA-1 cells by inducing cell cycle arrest and apoptosis. The combination of proapoptosis agents and antiautophagy agents could effectively enhance anticancer efficacy, which may be a new strategy in treating non-small cell lung cancer.

Antitumor Effect of By-1 from Spent Broth from Submerged Cultures of Stout Camphor Medicinal Mushroom, Taiwanofungus camphoratus (Higher Basidiomycetes), on A549 Adenocarcinoma Cells.

By-1 was obtained from spent broth from submerged cultures of Taiwanofungus camphoratus. This report evaluates the effects of By-1 on plate clone formation, wound healing, cell cycle, activated caspase-3 expression, and ROS release in A549 lung cancer cells. The result of plate clone formation assay revealed that By-1 could dramatically inhibit the viability of A549 cells in vitro. The inhibitory effect of By-1 on cell migration was tested using a wound healing assay. Proliferation rates of A549 cells were significantly inhibited following exposure to By-1 (12.5, 50, and 80 µg/mL). Flow cytometry revealed that the extracts increased, in a concentration-dependent manner, the number of cells in the G0/G1 phases of the cell cycle. The results of the caspase-3 experiment suggested that By-1 could induce A549 cells apoptosis, and this apoptosis was related to the release of reactive oxygen species by the A549 cells. All these results indicate that By-1 has potential in anti-lung cancer drug development.

Idiopathic abdominal cocoon syndrome with unilateral abdominal cryptorchidism and greater omentum hypoplasia in a young case of small bowel obstruction.

Abdominal cocoon syndrome (ACS) is a rare cause of intestinal obstruction due to total or partial encapsulation of the small intestine by a fibrocollagenous membrane. Idiopathic ACS with abdominal cryptorchidism and greater omentum hypoplasia is even rarer clinically. We successfully treated a 26-year-old male case of small bowel obstruction with acute peritonitis. He was finally diagnosed with idiopathic ACS with unilateral abdominal cryptorchidism and greater omentum hypoplasia during exploratory laparotomy. He then underwent enterolysis, cryptorchidectomy, and appendectomy. He recovered gradually from the operations and early postoperative inflammatory ileus. There has been no recurrence of intestinal obstruction since the operation, and he is still in follow-up. We analyzed his clinical data and retrospectively reviewed the literature, and our findings may be helpful for the clinical diagnosis and treatment on ACS.

Effects of the updated national emission regulation in China on circulating fluidized bed boilers and the solutions to meet them.

The advantage of circulating fluidized bed (CFB) boilers in China is their ability to utilize low rank coal with low cost emission control. However, the new National Emission Regulation (NER) issued in early 2012 brings much more stringent challenges on the CFB industries, which also causes much attention from other countries. Based on the principle of a CFB boiler and previous operating experience, it is possible for the CFB boilers to meet the new NER and maintain the advantage of low cost emission control, while, more influences should be considered in their design and operation. To meet the requirement of the new NER, the fly ash collector should adopt a bag house or combination of electrostatic precipitator and bag filter to ensure dust emissions of less than 30 mg · Nm(-3). For SO2 emission control, the bed temperature should be strictly lower than 900 °C to maintain high reactivity and pores. The limestone particle size distribution should be ranged within a special scope to optimize the residence time and gas-solid reaction. At the same time, the injecting point should be optimized to ensure fast contact of lime with oxygen. In such conditions, the desulfurization efficiency could be increased more than 90%. For lower sulfur content fuels (<1.5%, referred value based on the heating value of standard coal of China), increasing Ca/S enough could decrease SO2 emissions lower than that of the new NER, 100 mg · Nm(-3). For fuels with sulfur content higher than 1.5%, some simplified systems for flue gas desulfurization, such as flash dryer absorber (FDA), are needed. And the NOx emissions of a CFB can be controlled to less than 100 mg · Nm(-3) without any equipment at a bed temperature lower than 900 °C for fuels with low volatiles content (<12%), while for fuels with high volatiles, selective non-catalytic reduction (SNCR) should be considered. Due to the unique temperature in CFB as well as the circulating ash, the efficiency of SNCR could reach as high as 70%. The Hg emission of CFB is very low for the new NER due to its innate property.

Chitosan-DNA microparticles as mucosal delivery system: synthesis, characterization and release in vitro.

BACKGROUND: Mucosal immunity is important to defense against dental caries. To enhance mucosal immunity, a DNA vaccine mucosal delivery system was prepared by encapsulating anticaries DNA vaccine (plasmid pGJA-P/VAX) in chitosan under optimal conditions and the characteristics of the microparticles was investigated. Furthermore, the release properties and protective action of microparticles for plasmid were studied in vitro. METHODS: Plasmid loaded chitosan microparticles were prepared by complex coacervation. Three factors, concentration of DNA, sodium sulfate, and the chitosan/DNA ratios in complexes [better expressed as N/P ratio: the number of poly nitrogen (N) per DNA phosphate (P)] influencing preparation were optimized by orthogonal test. The characteristics of microparticles were evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). DNA release rate of microparticles in similar gastro fluid (SGF) or similar intestinal fluid (SIF) at 37 degrees C was determined by ultraviolet spectrophotometry. RESULTS: High encapsulation efficiency (96.8%) was obtained with chitosan microparticles made under optimal conditions of 50 mmol/L Na2SO4, 200 microg/ml DNA and N/P ratio of 4. The size of particles was about 4 to 6 microm. The encapsulation process did not destroy the integrity of DNA. When incubated with SIL, after a release of about 10% in the first 60 minutes, no further DNA was released during the following 180 minutes. When incubated with SGL, the microparticles released a small burst (about 11%) in the first 60 minutes, and then slowly released at a constant, but different rate. CONCLUSIONS: These chitosan microparticles showed suitable characteristics in vitro for mucosal vaccination and are therefore a promising carrier system for DNA vaccine mucosal delivery.