Bicyklo[4.4.0]dekan. Metoda oznaczania w powietrzu na stanowiskach pracy

Bicyclo[4.4.0]decane (BCD), also known as decalin, is a colorless liquid with the scent of camphor, menthol and naphthalene. This substance can be fatal if swallowed or entered a respiratory tract. It can cause severe skin burns and eye damage, and is toxic if inhaled. The aim of this study was to develop a method for determining BCD in workplace air, which will allow the determination of its concentrations at the level of 5 mg/m3 . The method was based on adsorption of BCD vapors on activated carbon, desorption with acetone solution in carbon disulfide and chromatographic analysis of the obtained solution. The study was performed with a gas chromatograph (GC) with a flame ionization detector (FID) equipped with a DB-VRX capillary column (60 m × 0.25 mm, 1.4 µm). The method was validated in accordance with the requirements of Standard No. EN 482. The method allows the determination BCD in workplace air in the concentration range 5–200 mg/m3 . The method for determining BCD has been recorded in the form of an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Akrylonitryl. Metoda oznaczania w powietrzu na stanowiskach pracy Anna Jeżewska, Agnieszka Woźnica

Acrylonitrile (AN) is highly flammable, colorless liquid with an unpleasant odor. Acrylonitrile is used in industry to produce polyacrylonitrile (PAN) and its copolymers. Acrylonitrile can cause cancer. The aim of this study was to develop a method for determining acrylonitrile in workplace air which will allow determination of its concentrations at the level of 0.1 mg/m3 . The method was based on adsorption of acrylonitrile vapors on activated carbon, desorption with acetone solution in carbon disulfide and chromatographic analysis of the obtained solution. The study was performed using a gas chromatograph (GC) with a flame ionization detector (FID) equipped with a DB-VRX capillary column (60 m × 0.25 mm, 1.4 µm). The method was validated in accordance with the requirements of Standard No. EN 482. The method allows the determination of acrylonitrile in workplace air at the concentration range from 0.1 to 2 mg/m3. The method for determining acrylonitrile has been recorded in the form of an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

History, Anatomy, Histology, and Embryology of the Ventricles and Physiology of the Cerebrospinal Fluid

Cerebrospinal fluid is an essential, clear, and colorless liquid for the homeostasis of the brain and neuronal functioning. It circulates in the brain ventricles, the cranial and spinal subarachnoid spaces. The mean cerebrospinal fluid volume is 150 ml, with 125 ml in subarachnoid spaces and 25 ml in the ventricles. Cerebrospinal fluid is mainly secreted by the choroid plexuses. Cerebrospinal fluid secretion in adults ranges between 400 and 600 ml per day and it is renewed about four or five times a day. Cerebrospinal fluid is mainly reabsorbed from arachnoid granulations. Any disruption in this well-regulated system from overproduction to decreased absorption or obstruction could lead to hydrocephalus.

Circulation of Cerebrospinal Fluid (CSF)

Circulation of cerebrospinal fluid (CSF) is a clear, colorless liquid that circulates between the ventricular system and the subarachnoid space. In addition to its function as a natural cushion for the brain, CSF provides the circulation of metabolic products, hormones, and neurotransmitters. Moreover, it has tasks such as maintaining the homeostatic balance of the central nervous system, protecting the brain against mechanical injuries, preventing direct contact of the brain with the extracellular region. It also has a role in maintaining cerebral interstitial fluid (ISF) homeostasis and neuronal regulation. Normal CSF production, its circulation, and absorption have a critical role for the development and functioning of the brain. In an average adult person, roughly 150 ml of CSF circulates at any given moment. The ventricular part accounts for about 17% of the total volume of fluid, with the rest located in the subarachnoid cisterns and space. CSF is produced at a rate of about 0.3–0.4 mL/min, translating to 18–25 mL/H and 430–530 mL/day.

N-Methylformamide. Documentation of proposed values of occupational exposure limits (OELs)

N-Methylformamide is a colorless liquid with an ammoniacal odor, used as a solvent and an intermediate for chemical reactions. There are no data on occupational exposure in Poland. N-Methylformamide is very well absorbed into the human body. The LD50 values for N-methylformamide administered to animals in various routes are similar (2600 ÷ 4000 mg/kg bw). After single or short-term administration of the compound in doses of 100 ÷ 1200 mg/kg bw. worsening symptoms of liver damage have been observed. No-observed adverse effect concentration (NOAEC) was established at 120 mg/m3 (two-week inhalation exposure in rats). Increase of hepatotoxic effect of N-methylformamide were observed at concentrations of 320 mg/m3 and 980 mg/m3. There are no data on sub-chronic, chronic and carcinogenic effects of the compound in laboratory animals. N-Methylformamide was not mutagenic and genotoxic. It caused embryotoxic and teratogenic effects. The NOAEC value (120 mg/m3) was used as the basis for determining the MAC (maximum acceptable concentration) value for N-methylformamide, and the MAC value for N-methylformamide was calculated at 3.3 mg/m3. There are no basis to determine the short-term value (STEL) and biological limit value (BLV). It has been proposed to label the compound as "Ft" (toxic for reproduction) and "skin" (skin absorption of the substance may be as important as inhalation exposure). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering

Caged structural water molecules emit tunable brighter colors by topological excitation

Intrinsically, free water molecules are colorless liquid. If it is colorful, why and how does it emit the bright colors? We provided direct evidences that, when water was trapped into...

HAZOP and ALOHA Analysis of Acetone

A potential hazard can happen because of a technical and personal failures, natural disasters, terrorist attacks, and fires. The potential hazards can be dangerous for human health and environment, also cause economic losses. In an industrial plant, prevention and control of these consequences have an importancy. Hazard and Operability Analysis (HAZOP) is a technique for a system evaluation and determination of risk management of hazards. In particular, HAZOP is used in order to determine potential hazards in a system and operability problems. Moreover, Areal Location of Hazardous Atmosphere (ALOHA) is the potential hazard modelling programme, which is used to plan chemical emergencies. Acetone, a colorless liquid also known as propanone, is a solvent used in manufacture of plastics and other industrial products. The most hazardous property of acetone is its flammability. Acetone is a solvent widely used in the chemical industries and stored in large volumes, therefore, acetone is an important source of danger for chemical processes.  In this study, acetone was investigated to be a hazardous chemical using HAZOP and ALOHA software in order to prevent and control a big hazardous event in an industrial plant. 

Pathomorphological characteristics of viral hemorrhagic disease of rabbits

The dead animals have a pathomorphological picture with a brightly expressed hemorrhagic diathesis, in many organs there is venous stasis. Blood does not clot for several hours, and at autopsy of organs (heart, lungs, liver, kidneys) it is poured in significant amounts into the body cavity. Macroscopically, the most significant changes are observed in the respiratory system. The lungs are blood-filled, intensely swollen and unevenly colored, have a grayish-pink color with single or multiple spotted and spotted hemorrhages under the pleura. Red or almost colorless liquid flows down from the incision surface, foamy exudate is released from the bronchi when pressed on. There are no patterns in the localization of pathomorphological changes in any part of the lungs (apical, cardiac, diaphragmatic): all parts are damaged at once, or mainly in one or another part. The walls of the trachea, nasal cavities, to a lesser extent the larynx are distinctly hemorrhagic. Their red color is more often caused by venous hyperemia. The lumen of the trachea and larynx is filled with red or colorless foamy fluid. Changes in the liver are constant, but not always the same type and are due to the degree of its blood supply, which causes a change in color, amount and consistency. In the first hours after the death of the animal, the liver is usually completely blood-filled, enlarged, easily torn, has a reddish-brown color with a yellowish tinge in the central parts of the lobes. The capillary network of the body looks like red streaks and dots of irregular shape. Spotted hemorrhages are sometimes observed under the capsule of the organ. The gallbladder contains some bile, its mucous is rough, a bit exfoliated. The spleen is increased in size by 1.5–3 times, swollen, dark cherry in color with a typical purple tinge. The kidneys are completely blood-filled, reddish-brown and increased in several times. The thymus is slightly reddened, often with multiple spotted or spotted hemorrhages in the chest. Lymph nodes are pulpy, grayish-pink, rarely red, not significantly changed in size. The heart (especially its right half) is filled with a large amount of black and red blood, increased in size , the walls of the ventricles are stretched, thin, have flabby consistency. Multiple spotted and spotted hemorrhages under the epicardium and endocardium are common. Changes in the gastrointestinal tract characterize catarrhal (rarely catarrhal-hemorrhagic) inflammation, sometimes hemorrhage in the duodenum and rectum, exfoliation of the gastric mucosa. In the form of hemorrhage, pathological and anatomical changes are found in the uterus and adrenal glands, in the form of congestive hyperemia – in the genitals, goiter, brain.

Microbial Diversity of Acetic Acid Producing Bacteria from Protein-Rich Residues

Background: Acetic acid bacteria (AAB) are concrete sets of organism which act as precursor for acetic acid production. Acetic acid is a colorless liquid with strong pungent and sour smell. It is synthesized from oxidation of ethanol by AAB. Vast studies have been made from sugary sources in the isolation of AAB. Aim: The needs to study and utilize our protein-rich residues (PRR) for AAB presence spurn this study. Place and Duration of Study: Department of Microbiology, University of Port Harcourt, between June and December 2018. Methodology: The samples (beans, groundnut and powdered milk) used in this study were surface-sterilized, homogenized, pre-enriched (in balsam medium) and serially diluted with inoculum size (0.1ml) inoculated on sterilized glucose yeast peptone agar, Mannitol agar and low glycemic index (LGI) media and incubated at 30oC for 48 h using the spread plate technique. A total of 11 bacterial isolates were obtained and screened for acetic acid production in brain heart infusion and yeast glucose ethanol acetic acid broth at 30oC for 14 days and positive isolates were identified by titration method. AAB isolates with the highest acetic acid concentration were selected for molecular identification and further studies. Results: Two Acetic acid bacteria identified in this study were Acetobacter and Gluconobacter. The result of this study indicated that Acetobacter had acetic acid concentration of 3.6g/100ml while Gluconobacter had 1.8g/100 ml. However, molecular identification highlighted Acetobacter as Bacillus cereus with Genbank accession number MK 332142; whereas Gluconobacter was Stenotrophomonas maltophilia MK 332143. The neighbor-joining phylogenetic tree and bioinformatics revealed B. cereus and S. maltophilia as 97% and 96% similarity index, 854 and 883 nucleotide sequencing letters as well as 450 and 410 base pairs. Conclusion: This finding implied that “S. maltophilia” and “B. cereus” are predominant Acetic acid bacteria in spoilt beans and groundnut; and can act as potential strains with industrial importance to man and environment.

Methyl Linoleate Synthesis From Cotton Seeds Oil : Optimization Study

Methyl esters are derivatives of triglycerides (oils or fats) that can be produced through esterification and transesterification process. One example of the methyl esters are widely used as an industrial raw material is methyl linoleate. Methyl linoleate is a colorless liquid with molecular formula C19H34O2. Methyl linoleate is a fatty acid ester and has a lot of common use as biodiesel ingredient, textiles, in medical research, emulsifiers and lubricants. The raw materials commonly used for the synthesis of methyl esters are palm oil, coconut oil, soybean oil, and others. But these oils are edible oil materials, so that in this case the raw materials that will be used is the cotton seed that has not been exploited well. The optimization reaction of the methyl linoleate synthesis through enzymatic transesterification from cotton (Ceiba pentandra L.) seed oils and methanol by Response Surface Methodology (RSM) was carried out. Immobilized lipase (lipozymeTL IM) used as catalyst. This research aims to optimize the reaction by observing variety of conditions that are influenced by several variables, such asreaction time, molar ratio, the amount of enzyme and the reaction temperature. Design Expert v.7 software used to view the interaction between the variables via RSM. The mathematical equations and statistical methods showed that the optimum condition of the enzymatic transesterification was obtained at 0.15 gram of amount of the enzyme, the ratio of cotton seed oils: methanol of 1: 2.05 (g/g), a reaction time of 14 hours and a temperature of 49.95 oC with the predicted and actual percentages yield of 37.87 and 38.24%, respectively. The model recommended for obtaining optimum results is a quadratric model with a R-squared value of 0.6957. Keywords: Methyl linoleate, Cotton seed oils, Lipozyme, Optimization study, Design Expertv.7