Effect of baicalin on eradicating biofilms of bovine milk derived Acinetobacter lwoffii.

BACKGROUND: Acinetobacter lwoffii (A.lwoffii) is a serious zoonotic pathogen that has been identified as a cause of infections such as meningitis, bacteremia and pneumonia. In recent years, the infection rate and detection rate of A.lwoffii is increasing, especially in the breeding industry. Due to the presence of biofilms, it is difficult to eradicate and has become a potential super drug-resistant bacteria. Therefore, eradication of preformed biofilm is an alternative therapeutic action to control A.lwoffii infection. The present study aimed to clarify that baicalin could eradicate A.lwoffii biofilm in dairy cows, and to explore the mechanism of baicalin eradicating A.lwoffii. RESULTS: The results showed that compared to the control group, the 4 MIC of baicalin significantly eradicated the preformed biofilm, and the effect was stable at this concentration, the number of viable bacteria in the biofilm was decreased by 0.67 Log10CFU/mL. The total fluorescence intensity of biofilm bacteria decreased significantly, with a reduction rate of 67.0%. There were 833 differentially expressed genes (367 up-regulated and 466 down-regulated), whose functions mainly focused on oxidative phosphorylation, biofilm regulation system and trehalose synthesis. Molecular docking analysis predicted 11 groups of target proteins that were well combined with baicalin, and the content of trehalose decreased significantly after the biofilm of A.lwoffii was treated with baicalin. CONCLUSIONS: The present study evaluated the antibiofilm potential of baicalin against A.lwoffii. Baicalin revealed strong antibiofilm potential against A.lwoffii. Baicalin induced biofilm eradication may be related to oxidative phosphorylation and TCSs. Moreover, the decrease of trehalose content may be related to biofilm eradication.

Pseudomonas aeruginosa biofilm dispersion by the mouse antimicrobial peptide CRAMP.

Pseudomonas aeruginosa (P. aeruginosa) is a known bacterium that produces biofilms and causes severe infection. Furthermore, P. aeruginosa biofilms are extremely difficult to eradicate, leading to the development of chronic and antibiotic-resistant infections. Our previous study showed that a cathelicidin-related antimicrobial peptide (CRAMP) inhibits the formation of P. aeruginosa biofilms and markedly reduces the biomass of preformed biofilms, while the mechanism of eradicating bacterial biofilms remains elusive. Therefore, in this study, the potential mechanism by which CRAMP eradicates P. aeruginosa biofilms was investigated through an integrative analysis of transcriptomic, proteomic, and metabolomic data. The omics data revealed CRAMP functioned against P. aeruginosa biofilms by different pathways, including the Pseudomonas quinolone signal (PQS) system, cyclic dimeric guanosine monophosphate (c-di-GMP) signalling pathway, and synthesis pathways of exopolysaccharides and rhamnolipid. Moreover, a total of 2914 differential transcripts, 785 differential proteins, and 280 differential metabolites were identified. A series of phenotypic validation tests demonstrated that CRAMP reduced the c-di-GMP level with a decrease in exopolysaccharides, especially alginate, in P. aeruginosa PAO1 biofilm cells, improved bacterial flagellar motility, and increased the rhamnolipid content, contributing to the dispersion of biofilms. Our study provides new insight into the development of CRAMP as a potentially effective antibiofilm dispersant.

L-Arginine protects mouse Leydig cells against T-2 toxin-induced apoptosis in vitro.

To explore the protective mechanism of L-arginine against T-2 toxin-induced apoptosis in mouse Leydig cells, we investigated whether L-arginine can prevent T-2 toxin-induced apoptosis in mouse Leydig cells and explored the underlying mechanisms. Leydig cells were isolated and cultured with control, T-2 toxin (10 nM), L-arginine (0.25, 0.5, and 1.0 mM), and T-2 toxin (10 nM T-2 toxin) + L-arginine (0.25, 0.5, or 1.0 mM) for 24 h. Cells and supernatants were harvested to examine proliferation of the cells, the apoptosis rate, activity of caspase-3 and mitochondria, and the gene expression levels of Bcl-2, Bax, PARP, and caspase-3. Results showed that proliferation and mitochondrial activity of Leydig cells were inhibited by administration of T-2 toxin. Bcl-2 gene expression levels was decreased, while the gene expression levels of Bax and PARP were increased, which could trigger mitochondria-mediated apoptosis, activate downstream caspase-3, and then increased caspase-3 at both activity and gene expression levels. The expression of the Bcl-2 gene was upregulated and the expression of Bax, caspase-3, and PARP gene were downregulated when L-arginine was added to the cultured cells. The results of this study showed that L-arginine could block T-2 toxin-induced apoptosis in mouse Leydig cells by regulating specific intracellular death-related pathways.

Cytotoxic glutarimide-containing polyketides isolated from Streptomyces sp. JCM 4793.

Glutarimide-containing polyketides usually exhibit anti-fungi activity, which was well exampled by cycloheximide. In our work, three new polyketide structures, 12-amidestreptimidone (1), 12-carboxylstreptimidone (2) and 3-(5S,8R)-(2-amino-2-oxoethyl-2'-methoxy-2'-oxoethyl)-8,10-dimethyl-7-oxododeca-5-hydroxy-9E,11-diolefin (3) were isolated from Streptomyces sp. JCM 4793. 3 without the glutarimide moiety is not active against fungi as expected, while 1 bearing the amide moiety is much more active than its carboxylic form 2. Here we report the isolation, structural elucidation, antifungal activity, and proposed biosynthesis pathway of 1-3.

Five new limonoids isolated from Walsura robusta.

Five new toosendanin limonoids with highly oxidative furan ring walsurobustones A-D (1-4), and one new furan ring degraded limonoid walsurobustone E (5) together with one known compound toonapubesic acid B (6) were isolated from the leaves of Walsura robusta. Their structures were elucidated by NMR and MS data. Especially, the absolute configuration of toonapubesic acid B (6) was confirmed by X-ray diffraction study. Compounds 1-6 exhibited good cytotoxicity against the cancer cell lines HL-60, SMMC-7721, A-549, MCF-7, and SW480.

Codon preference optimization increases prokaryotic cystatin C expression.

Gene expression is closely related to optimal vector-host system pairing in many prokaryotes. Redesign of the human cystatin C (cysC) gene using the preferred codons of the prokaryotic system may significantly increase cysC expression in Escherichia coli (E. coli). Specifically, cysC expression may be increased by removing unstable sequences and optimizing GC content. According to E. coli expression system codon preferences, the gene sequence was optimized while the amino acid sequence was maintained. The codon-optimized cysC (co-cysC) and wild-type cysC (wt-cysC) were expressed by cloning the genes into a pET-30a plasmid, thus transforming the recombinant plasmid into E. coli BL21. Before and after the optimization process, the prokaryotic expression vector and host bacteria were examined for protein expression and biological activation of CysC. The recombinant proteins in the lysate of the transformed bacteria were purified using Ni(2+)-NTA resin. Recombinant protein expression increased from 10% to 46% based on total protein expression after codon optimization. Recombinant CysC purity was above 95%. The significant increase in cysC expression in E. coli expression produced by codon optimization techniques may be applicable to commercial production systems.

Field electron emission from hydrogen plasma treated nano-ZnO thin films.

A nano-Zno films are deposited on the Mo film/ceramic substrates by using the electron beam vapor deposition technique. Then a hydrogen plasma treated method is used to improve the characteristics of ZnO thin films by microwave plasma chemical vapor deposition system. Effects of process parameters on morphologies and structures of the ZnO thin films are detected and analysed by field emission scanning electron microscopy, X-ray diffraction spectrum and energy dispersive spectrum. The experimental result indicates that the hydrogen plasma treated techniques can essentially reduce the surface resistance and improve the field emission current density of the nano-ZnO thin films. For the hydrogen plasma treated sample, its field emission current density can increased more than three times at 2.2 V/microm electric field condition.

[Using plant extracts and their active ingredients to inhibit bacterial biofilms].

Numerous studies have reported that the resistance of biofilm bacteria to antibiotics can be up to 10-1 000 fold higher than that of planktonic bacteria. Bacterial biofilms are reported to be responsible for more than 80% of human microbial infection, posing great challenges to the healthcare sector. Many studies have reported that plant extracts and their active ingredients can inhibit the formation and development of bacterial biofilms, including reducing biofilm biomass and the number of viable bacteria in biofilms, as well as eradicating mature biofilms. This review summarized the plant extracts and their active ingredients that are inhibitory to bacterial biofilms, and analyzed the underpinning mechanisms. This review may serve as a reference for the development of plant drugs to prevent and treat biofilm infections.

[Bacterial biofilms: novel strategies for intestinal colonization by probiotics].

Probiotics can improve the microecological balance of the body and have special effects in promoting nutrient absorption, controlling intestinal infections, and regulating immune function. However, there are problems such as difficult colonization in the gastrointestinal environment and low oral bioavailability. Bacterial biofilms are organized bacterial cells that adhere to an abiotic or biotic surface and are enclosed in extracellular polymeric substances of exopolysaccharides (EPS), extracellular DNA (eDNA), proteins and lipids, with a three-dimensional spatial structure. Probiotics with the help of bacterial biofilms have obvious advantages over planktonic bacteria in stress resistance, combating pathogens and modulating the host's immune function, which provides a new research idea for the development of probiotics. This paper expounded on the advantages of probiotics with the help of bacterial biofilms, and focused on introducing substances that could promote the formation of probiotic biofilms and the mechanisms, and the safety of probiotic biofilms. Currently, research on probiotic biofilms is still in its infancy, and this paper is expected to provide references for future research in this field.

[(99)Tc(m)-MIBI exercise stress single photon emission computed tomography myocardial perfusion imaging of patients with myocardial bridge].

OBJECTIVE: To observe the exercise single photon emission computed tomography (SPECT) myocardial perfusion imaging of patients with myocardial bridge and assess the association between myocardial ischemia and extent of myocardial systolic compression. METHODS: Seventeen patients with myocardial bridge diagnosed by coronary angiogram were included and underwent exercise SPECT myocardial perfusion imaging. RESULTS: Abnormal SPECT perfusion imaging was evidenced in 12 out of 17 patients with myocardial bridge (2 out of 6 patients with systolic compression induced stenosis < 50%, 3 out of 4 patients with systolic compression induced stenosis between 50% - 75% and 7 out of 7 patients with the systolic compression induced stenosis between 75% - 100%). CONCLUSION: Exercise stress SPECT myocardial perfusion imaging could detect myocardial ischemia in patients with myocardial bridge and abnormal perfusion is positively related to the extent of systolic compression induced stenosis.

The FAM171A2 gene is a key regulator of progranulin expression and modifies the risk of multiple neurodegenerative diseases.

Progranulin (PGRN) is a secreted pleiotropic glycoprotein associated with the development of common neurodegenerative diseases. Understanding the pathophysiological role of PGRN may help uncover biological underpinnings. We performed a genome-wide association study to determine the genetic regulators of cerebrospinal fluid (CSF) PGRN levels. Common variants in region of FAM171A2 were associated with lower CSF PGRN levels (rs708384, P = 3.95 × 10-12). This was replicated in another independent cohort. The rs708384 was associated with increased risk of Alzheimer's disease, Parkinson's disease, and frontotemporal dementia and could modify the expression of the FAM171A2 gene. FAM171A2 was considerably expressed in the vascular endothelium and microglia, which are rich in PGRN. The in vitro study further confirmed that the rs708384 mutation up-regulated the expression of FAM171A2, which caused a decrease in the PGRN level. Collectively, genetic, molecular, and bioinformatic findings suggested that FAM171A2 is a key player in regulating PGRN production.

Exploring barriers to implementation of smoking policies: a qualitative study on health professionals from three county-level hospitals.

OBJECTIVE: This study was to identify factors limiting the implementation of smoking policies in county-level hospitals. METHODS: We conducted qualitative interviews (17 focus groups discussions and 6 one-to-one in depth interviews) involving 103 health professionals from three target county-level hospitals. A combination of purposive and convenience sampling was used to recruit subjects and gain a broad range of perspectives on issues emerging from ongoing data-analysis until data saturation occurred. The transcripts were analyzed for themes and key points. RESULTS: The main themes that emerged suggested that both smokers and non-smokers viewed smoking very negatively. However, it was clear that, underlying this acceptance of the health risks of smoking, there was a wide range of beliefs. Most of the health professionals pointed out that, as smoking was legal, addictive, and influenced by social norms, currently it was almost unrealistic to expect all smokers to give up smoking or not to smoke in the hospitals. Furthermore, they were concerned about the potentially detrimental effects of providing counseling advice to all smokers on the interpersonal relationship among colleagues or between doctors and patients. In addition, low level of employee participation influenced the sustainable implementation of smoking policies. CONCLUSIONS: Simply being aware of the health risks about smoking did not necessarily result in successful implementation of the smoking policies. Application of comprehensive intervention strategies such as implementing smoking policies in public places at the county level, creating supportive environments, promoting community participation, and conducting health education, may be more effective.

[The current status of passive smoking in Chinese families and associated factors].

OBJECTIVE: To understand the prevalence of passive smoking in Chinese families and discuss its associated factors, as to providing scientific evidence for establishing tobacco control measures in China. METHOD: Cross-sectional survey: from June to September, 2004, we randomly selected six counties in three different provinces ( Mianzhu and Xichong of Sichuan Province; Anyi and Hukou of Jiangxi Province; Xinan and Yanshi of Henan Province) and performed face-to-face questionnaire survey on citizens between 18 and 69 years old. All the data were double independently input by professional data entry company to ensure data accuracy. The prevalence of home passive smoking exposure in families with different demographic characteristics was described by using prevalence, and the possible correlated factors of home passive smoking exposure as independent variables, multiple factors were analyzed using Logistic Stepwise Regression Analysis method. RESULTS: The analysis on 8142 nonsmokers revealed that the rate of passive smoking was 28.42%, with 27.38% of male and 28.93% of female suffering from passive smoking. All 87.19% of the smokers would smoke in front of their families. As many as 42.14% of the nonsmokers would offer cigarettes to their guests, while about 46.82% of the nonsmokers would suggest smokers to smoke outdoor. Home restriction on tobacco was extremely rare and only 6.33% of all the families completely forbade smoking. Multivariate logistic regression analysis of non-conditions revealed that, there was a lower level of involuntary tobacco smoke exposure in female, older age group, lower education level, divorced, or widowed families. There was no difference in involuntary tobacco smoke exposure between town dwellers and county dwellers, but such difference did exist in different districts. CONCLUSION: The three provinces under investigation should have severe involuntary tobacco smoking exposure. Gender, age, literacy level, occupation and region should be all factors that influence the status of involuntary tobacco smoking exposure in different families. There is a high percentile that smokers would smoke in front of their families and kids and a relative low pressure against smoking from nonsmokers. Cigarette offering is very prevalence. The knowledge and attitude about passive smoking should be separated from the situation of passive smoking exposure.

Effects of estradiol on depressive-like behavior of ovariectomized rats and its possible mechanism / 解剖学报

Objective To examine the effect of estradiol (E2) treatment on ovariectomy (OVX) induced depressive-like behavior and possible mechanism by measuring inflammatory biomarkers levels oi interleukin-6 (IL-6) and tumor necrosis tactor-(x (TNF-ot) and brain-derived neurotrophic factor (BDNF) expression in amygdaia nucleus. Methods Thirty nine healthy aduit 缶male SD rats were randomly divided into three groups : sham operation group (SO), ovariectomized group (OVX) and ovariectomized estradiol treatment group (OVX + E2). After 6 weeks of E2 treatment, depressive like behavior was evaluated by opening field test (OFT) and sugar water preference test (SPT). The levels of inflammatory factors IL-6 and TNF-a in amygdala were measured by ELESA, and the expression of BDNF in rat amygdala was detected by immunohistochemical staining. Results The result of the SPT showed that OVX significantly decreased the sugar intake and sugar preference rate of rats, and E2 treatment significantly increased sugar water intake and sugar water preference rate of rats. The result of the OFT showed that OVX significantly decreased the numbers of crossing and rearing of rats, and reduced the time spent in the centre ; E2 treatment significantly increased the numbers of crossing and rearing of rats, and prolonged the time spent in the centre. ELESA and immunohistochemical analysis found the levels of IL-6 and TNF-a in amygdala increased significantly, while the average absorbance (AA) of BDNF in the amygdala reduced significantly (P<0.01 respectively) of rats in OVX group when compared with the SO group. And the levels of IL-6 and TNF-a in amygdala decreased significantly (P<0.01 respectively), while the A4 of BDNF increased significantly (P< 0.05) in the amygdala of rats in the OVX+EX group when compared with the OVX group. The difference was statistically significant. Conclusion E2 treatment improved depression-like behavior of OVX rats is partly due to increased antiinflammatory and activated the BDNF expression in amygdaloid nucleus, thus enhancing the neuroprotective effect of OVX rats.

Effects of treadmill exercise on learning and memory of the vascular dementia rats and its mechanism / 解剖学报

Objective To observe the effects of 4-week low intensity treadmill exercise on the learning and memory, amino acid levels and the protein expression of protein kinase A ( PKA) , cyclic adenosine monophosphate response element binding protein( CREB) and brain-derived neurotrophic factor(BDNF) in the prefrontal cortex (PFC) of the vascular dementia (VD) rats. Methods Thirty-nine SD rats were randomly allocated to 3 groups, sham group (sham, n= 13) , vascular dementia group (VD, n= 13) and vascular dementia treaded with exercise group (VD + EX, n= 13). Chronic cerebral ischemia model in VD group and VD+EX group rats were established by permanent ligation of bilateral, then VD+EX group rats were submitted to 4-week low intensity treadmill exercise. After exercise, spatial learning and memory ability were evaluated by Moms water maze test ( MWM ) , glutamic ( Glu ) and gamma-aminobutyric acid (GABA) levels in the PFC were measured by high performance liquid chromatography( HPLC) ; the protein expression of PKA, CREB and BDNF in the PFC of rats were detected by Western blotting. Results The result of the MWM showed the average escape latency of rats in the VD group on the 1 -5 days was significantly higer than sham group, the time to first find the original platform was significantly prolonged and the platform crossings decreased significantly ( P 0. 05 ) between the two groups. Conclusion Four-week low-intensity running exercise improves the learning and memory ability of VD rats through enhancing the Glu level and activating PKA-CREB-BDNF signaling in the PFC of rats.

Toxicity evaluation of zinc oxide nanoparticles in vitro and in vivo on cornea / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe the toxic effects of zinc oxide nanoparticles(ZnO NPs)on cornea by constructing intoxicated model in vivo and in vitro.METHODS:Human corneal epithelial cells(HCEpiC)were cultured in vitro and exposed to different concentrations(0.5, 5, 12.5, 25, 50, 100, 250 μg/mL)of ZnO NPs for 24h. The cell culture medium without nano-solution was used as the blank control group. The viability of the cells was assessed by MTT assay. Three different concentrations(25, 50 and 100 μg/mL)of ZnONPs dispersions were exposed to the conjunctival sac of anesthetized mice three times a day for 7d consecutively. The phosphate buffered saline(PBS)eye group was the PBS control group. Corneal morphology was observed on 1, 3, 5 and 7d, and the eyes were removed on 8d for various laboratory examinations, including corneal pathological changes and expression levels of inflammatory factors(TNF-α, IL-6).RESULTS:After treatment of HCEpiC cells with different concentrations of ZnO NPs for 24h, the MTT results showed that Zno NPs cause damage to cells at 0.5 μg/mL, and the cell survival rate was about 80%(P&#x003C;0.05). Half of the cells were killed at a dose of 5 μg/mL, the damaging effect on cells in the concentration range of 5～250 μg/mL was concentration-dependent(P&#x003C;0.0001). After 7d of conjunctival capsule spotting in mice, dot-like staining of fluorescein was seen in the 25 μg/mL ZnO NPs and 50 μg/mL ZnO NPs groups. Localized circular fluorescein stained areas were seen in the corneas of the 100 μg/mL ZnO NPs group. HE staining showed that the corneal epithelial layer, stromal layer thickness and stromal layer immune cell number did not change significantly in the 25 μg/mL and 50 μg/mL ZnO NPs groups(all P&#x003E;0.05), while the corneal epithelial layer thinned, the corneal stromal layer thickened and the stromal layer immune cells increased significantly in the 100 μg/mL ZnO NPs group(all P&#x003C;0.05). Immunohistochemical staining showed that the number of corneal stromal immune cells producing TNF-α and IL-6 and the mean integral optical density(IOD)values of TNF-α and IL-6 were significantly higher in the 100 μg/mL ZnO NPs group than in the PBS control group(P&#x003C;0.05), and the degree of inflammation response was concentration-dependent. Compared with the PBS control group, no significant increase in immune cell count and IOD values in the 25 μg/mL ZnO NPs and 50 μg/mL ZnO NPs groups(P&#x003E;0.05).CONCLUSION:The toxic damaging effect of ZnO NPs on the cornea was confirmed from both in vitro and in vivo, which provided a theoretical basis for the ocular safety evaluation of ZnO NPs.

The mechanism of S100A7 inducing the migration and invasion in cervical cancer cells / 中华肿瘤杂志

Objective: To investigate the mechanism of S100A7 inducing the migration and invasion in cervical cancers. Methods: Tissue samples of 5 cases of cervical squamous cell carcinoma and 3 cases of adenocarcinoma were collected from May 2007 to December 2007 in the Department of Gynecology of the Affiliated Hospital of Qingdao University. Immunohistochemistry was performed to evaluate the expression of S100A7 in cervical carcinoma tissues. S100A7-overexpressing HeLa and C33A cells were established with lentiviral systems as the experimental group. Immunofluorescence assay was performed to observe the cell morphology. Transwell assay was taken to detect the effect of S100A7-overexpression on the migration and invasion of cervical cancer cells. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to examine the mRNA expressions of E-cadherin, N-cadherin, vimentin and fibronectin. The expression of extracellular S100A7 in conditioned medium of cervical cancer cell was detected by western blot. Conditioned medium was added into Transwell lower compartment to detect cell motility. Exosomes were isolated and extracted from the culture supernatant of cervical cancer cell, the expressions of S100A7, CD81 and TSG101 were detected by western blot. Transwell assay was taken to detect the effect of exosomes on the migration and invasion of cervical cancer cells. Results: S100A7 expression was positively expressed in cervical squamous carcinoma and negative expression in adenocarcinoma. Stable S100A7-overexpressing HeLa and C33A cells were successfully constructed. C33A cells in the experimental group were spindle shaped while those in the control group tended to be polygonal epithelioid cells. The number of S100A7-overexpressed HeLa cells passing through the Transwell membrane assay was increased significantly in migration and invasion assay (152.00±39.22 vs 105.13±15.75, P<0.05; 115.38±34.57 vs 79.50±13.68, P<0.05). RT-qPCR indicated that the mRNA expressions of E-cadherin in S100A7-overexpressed HeLa and C33A cells decreased (P<0.05) while the mRNA expressions of N-cadherin and fibronectin in HeLa cells and fibronectin in C33A cells increased (P<0.05). Western blot showed that extracellular S100A7 was detected in culture supernatant of cervical cancer cells. HeLa cells of the experimental group passing through transwell membrane in migration and invasion assays were increased significantly (192.60±24.41 vs 98.80±47.24, P<0.05; 105.40±27.38 vs 84.50±13.51, P<0.05) when the conditional medium was added into the lower compartment of Transwell. Exosomes from C33A cell culture supernatant were extracted successfully, and S100A7 expression was positive. The number of transmembrane C33A cells incubated with exosomes extracted from cells of the experimental group was increased significantly (251.00±49.82 vs 143.00±30.85, P<0.05; 524.60±52.74 vs 389.00±63.23, P<0.05). Conclusion: S100A7 may promote the migration and invasion of cervical cancer cells by epithelial-mesenchymal transition and exosome secretion.

Passive smoking in China: contributing factors and areas for future interventions.

OBJECTIVE: To reduce tobacco consumption and exposure to passive smoking in China. METHODS: Discussion consisting of 80 focus groups and 35 interviews were held in three rural intervention counties of Jiangxi, Henan, and Sichuan Provinces. Participants came from hospitals, schools, rural areas, and urban areas. RESULTS: Tobacco use and exposure to passive smoking were widely prevalent in the investigated schools, hospitals, county towns, and rural areas. Knowledge of the risks for passive smoking on health is lacking, especially in rural areas. Barriers to the control of tobacco use in public places include reluctance of administrators to implement tobacco control policies, lack of consistent policies, difficulties with regulations and enforcement, and reluctance of non-smokers to exercise their right to clean air. CONCLUSION: To curb the current tobacco epidemic in China, tobacco control efforts must focus on reducing exposure to passive smoking. A strategy should be formulated to reduce the factors that contribute to tobacco use and exposure to passive smoking.