Effect of carbon-rich biochar on mechanical properties of PLA-biochar composites

Agricultural biomass residues are emerged from harvesting and processing of agricultural crops. When the crop production increases, a large amount of biomass residues is produced and remained after cutting of peel, bunch, straw and stalk of crops. In this work, agricultural biomass residues (cassava rhizome, durian peel, pineapple peel and corncob) were selected as feedstock for carbon-rich biochar (CRB) production using a facile pyrolysis method. Proximate analysis and thermogravimetric analysis (TGA) were used to characterize biomass feedstock. The results showed that the percentage of fixed carbon in biomass feedstock ranged between 11.91% and 17.51%. Characteristic differences of the CRB were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The carbon content in the CRB was found to significantly depend on biomass origin. Interestingly, cassava rhizome, which has a higher percentage of fixed carbon, is a superior precursor for CRB production. The study of different pyrolysis temperature indicated that the carbon content of cassava rhizome derived CRB is increased with pyrolysis temperature. The tensile properties of composite between poly(lactic acid) PLA and different types of biomass-derived CRB were investigated. PLA composite incorporated with a higher carbon content-CRB tended to exhibit improved mechanical properties. Specifically, the elastic modulus and impact energy of PLA/CRB composite specimens increased remarkably with the incorporation of CRB powder. The current research indicates that CRB prepared from agricultural biomass residues could be a sustainable material for utilization in PLA biocomposites.     

Dermatotoxicology of sulfur mustard: Historical perspectives from World War I

Sulfur mustard has been used as a chemical warfare agent for the past century. After its introduction by the Germans in World War I, investigators quickly began studying its impact on the human body including its deleterious effects on skin. This review focuses on two groups in particular who conducted experiments from 1917 to 1918: the United States Army at the American University Experiment Station Laboratories and Torald Sollmann at Western Reserve University. Through this work, these researchers proved far ahead of their time by anticipating dermatologic phenomena not described in the literature until later in the twentieth century. These include regional variation of percutaneous penetration, effect of vehicle on penetration and predicting immunologic contact urticaria. The work conducted by these researchers set the groundwork for much of twentieth century dermatotoxicology.     

不同剂量硫磺熏蒸对党参化学成分的影响

目的 研究不同剂量硫磺熏蒸对党参化学成分的影响及硫熏党参贮藏不同时间化学成分的变化,为党参饮片的科学炮制及质量评价提供参考。方法 不同剂量硫磺熏蒸党参并贮藏期12个月,采用UV及HPLC方法测定党参多糖、5-羟甲基糠醛、党参炔苷等化学成分的变化。结果 硫磺熏蒸对党参多糖的影响较小,最高剂量（2.0%）硫熏,放置12个月,多糖含量降低5.83%;对5-羟甲基糠醛、党参炔苷的影响大,最高剂量（2.0%）硫熏,放置12个月,5-羟甲基糠醛含量增加83.27%,党参炔苷含量降低54.09%。结论 硫熏对党参化学成分有显著影响。应严格控制药材加工处理及炮制过程中硫磺的使用,确保中药材及饮片的质量。     

电感耦合等离子体-质谱法测定注射用益气复脉(冻干)中的硫元素

目的 采用电感耦合等离子体-质谱（ICP-MS）法建立注射用益气复脉（冻干）中硫元素的含量测定方法。方法 以微波消解法处理样品,硝酸为消解试剂,样品经微波消解后,以锗（Ge）元素为内标元素,采用ICP-MS法测定药液中硫元素的量。结果 硫元素质量浓度在1～15 μg/mL内线性关系良好（r=0.999 0）;准确度试验（n=6）平均回收率为95.4%,RSD值为5.9%;结论 该方法简便、快速、准确,可用于测定注射用益气复脉（冻干）中硫元素的含量,为其质量控制、安全性评价提供一定参考。     

N‐Acetylcysteine as a chemical scavenger for sulfur mustard: New insights by mass spectrometry

The vesicant sulfur mustard (SM) is a banned chemical warfare agent. Although, SM has been used in combat since WWI, there is no causal therapy currently available. Accordingly, development and investigation of antidotes and scavengers targeting SM are of high clinical relevance. N‐acetylcysteine (NAC) was shown to mitigate symptoms of SM intoxications in vitro and in vivo. However, it is still unclear whether the beneficial effects of NAC are only due to physiological processes or also due to chemical scavenging of SM. Therefore, in this study, we examined the scavenging potential of NAC toward SM. Co‐incubations of SM and different NAC concentrations in human serum were performed to monitor diverse adducts (covalent reaction products) of human serum albumin (HSA), NAC, and SM. After proteolytic cleavage of HSA with proteinase K the alkylated tripeptide hydroxyethylthioethyl‐CysProPhe (HETE‐CPF) and the disulfide bridged tripeptide NAC‐CPF were detected. Samples were analyzed by microbore liquid chromatography–electrospray ionization–high‐resolution tandem‐mass spectrometry (μLC‐ESI MS/HR MS). Furthermore, degradation kinetics of SM in phosphate buffered saline were measured in the presence and absence of NAC. Although NAC‐CPF was identified and characterized for the first time by mass spectrometry and reaction products of NAC and SM were detected and identified by MS/HR MS, analyses clearly documented minor reactivity not significantly contributing to reduction of SM concentrations. Therefore, we conclude that chemical scavenging of SM by NAC does not play the key role in NAC therapy of SM poisoning.     

Association between oral malodor and adult periodontitis: a review

BACKGROUND: Bad breath has a significant impact on our daily social life to those who suffer from it. The majority of bad breath originates within the oral cavity. However, it is also possible that it can come from other sources such as gastric-intestine imbalance. The term "oral malodor" is used to describe a foul or offensive odor emanating from the oral cavity, in which proteolysis, metabolic products of the desquamating cell, and bacterial putrefaction are involved. Recent evidence has demonstrated a link between oral malodor and adult periodontitis. The process of developing bad breath is similar to that noted in the progression of gingivitis/periodontitis. Oral malodor is mainly attributed to volatile sulfur compounds (VSC) such as hydrogen sulfide, methyl mercaptan and dimethyl sulfide. The primary causative microbes are gram-negative, anaerobic bacteria that are similar to the bacteria causing periodontitis. These bacteria produce the VSC by metabolizing different cells/tissues (i.e., epithelial cells, leukocytes, etc.) located in saliva, dental plaque, and gingival crevicular fluid. Tongue surface is composed of blood components, nutrients, large amounts of desquamated epithelial cells and bacteria, suggesting that it has the proteolytic and putrefactive capacity to produce VSC. One of the challenges in dealing with oral malodor is to identify a reliable test for detecting bad breath. AIMS: The purposes of this review article were: (1) to correlate the relationship between oral malodor and adult periodontitis; (2) to analyze current malodor tests and discuss available treatment regimens.     

Volatile sulfur compounds in mouth air from clinically healthy subjects and patients with periodontal disease

Volatile sulfur compounds (VSC) in mouth air were estimated by gas chromatography. The amount of VSC and the methyl mercaptan/ hydrogen sulfide ratio were significantly increased in patients with periodontal disease. These two parameters also increased in proportion to the bleeding index and probing depth. A study was also done on the effect of removal of tongue coating on VSC concentrations in mouth air from patients with periodontal involvement. VSC and the methyl mercaptan/hydrogen sulfide ratio were reduced to 49% and 35%, respectively, by removal of the tongue coating. The average amount of tongue coating removed from patients with periodontal disease was significantly higher than from controls (90.1 mg vs. 14.6 mg, p < 0.01). Estimated production of VSC from tongue coating was 4 times higher than the control value, and the methyl mercaptan/hydrogen sulfide ratio was also markedly increased. However, a saliva putrefaction study suggested that saliva does not contribute to the elevated ratio of methyl mercaptan in mouth air. These results strongly suggest that, in addition to periodontal pockets, tongue coating has an important role in VSC production, in particular leading to an elevated concentration of methyl mercaptan, which is more pathogenic than hydrogen sulfide.