Paraffin Removal Research Articles

Microbial Prevention of Wax Deposition in Crude Oil

Microorganisms were obtained by separation and purification experiment from waxy oil production wells in Daqing Oilfield. The paraffin removal strain was named for S1, and the biological surfactant strain was named for G1. Microscopic and morphological examinations showed strain S1 was to be Bacillus Subtilis and strain G1 was to be Bacillus Cereus. As an indicator of the degradation of paraffin, strain S1 and strain G1 were added in different proportions, the optimum proportion was 5:2. In this proportion the degradation rate of paraffin could reach to 64%, the prevention rate of paraffin could reach to 55%. By experiment after mixed bacteria group treatment, the viscosity of crude oil reduced from 36.9mPa•s to 27.8mPa•s, the reduction rate of viscosity was 24.7%, and the freezing point of crude oil reduced by 3.6°C, paraffinic hydrocarbons of crude oil were degraded.

Simulation Analysis Study on the Flow Field of the Collar in Sucker Rod

During oil well production, it was a serious phenomenon of wax deposition on the parts such as oil production system section break.For the fluid flow problem of the collar in sucker rod, the research of this thesis applies Flunt software to perform numerical simulation of the flow conditions under different outputs, and presents relevant velocity vector and velocity nephogram of the crude oil at the collar in sucker rod. Through analysis, it was believed that the wax deposition could not be efficiently settled only by high fluid velocity raised by output increase, and the relevant technical measures were proposed to prevent wax deposition, providing the theoretical thesis for paraffin removal and control at oil well.

Efficient DNA Extraction for HPV Genotyping in Formalin-Fixed, Paraffin-Embedded Tissues

DNA from archived FFPE can be used for papillomavirus genotyping, but potential problems include paraffin as a physical barrier, DNA cross-linking, and PCR inhibitors. To address these complications, we combined a commercially available DNA isolation kit (Qiagen DNeasy) with a heat treatment and evaluated the resulting DNA with regards to HPV typing. DNA was extracted from 10-μm sections from 150 FFPE cancer samples. One protocol followed the manufacturer's recommendation, including paraffin removal by xylene and tissue lysis at 56°C. A second section was directly incubated at 120°C and subsequently lysed at 65°C. After spin-column purification, both extracts were tested with a linear array HPV genotyping assay. Additionally, cellular DNA yield, HPV16 DNA copies, and PCR inhibitors were assessed by real-time qPCR assays. Inadequate linear array HPV genotyping assay results were significantly more frequent (P = 0.0003) in xylene-treated (29/150, 19.3%) than in heat-treated extracts (8/150, 5.3%). HPV detection also differed, with 94/150 (62.7%) and 110/150 (73.3%) positive results, respectively (P = 0.0026). The heat method also yielded more PCR-amplifiable cellular DNA (8.2-fold; P < 0.001) and HPV16 copies (6.5-fold; P = 0.009), although PCR inhibitors also had a greater effect (P = 0.035). Aggressive heat treatment demonstrated an advantage over traditional xylene purification protocols, resulting in higher DNA yields and increased sensitivity for HPV testing.

Leishmania sp. identification by PCR associated with sequencing of target SSU rDNA in paraffin-embedded skin samples stored for more than 30 years

Paraffin-embedded samples commonly stored at educational and research institutions constitute tissues banks for follow-up or epidemiological studies; however, the paraffin inclusion process involves the use of substances that can cause DNA degradation. In this study, a PCR protocol was applied to identify Leishmania strains in 33 paraffin-embedded skin samples of patients with American cutaneous leishmaniasis. DNA was obtained by the phenol-chloroform protocol following paraffin removal and then used in PCR or nested PCR based on the nucleotide sequence of the small subunit ribosomal RNA (SSU rDNA). The amplicons obtained were cloned and sequenced to determine the single nucleotide polymorphism that distinguishes between different Leishmania species or groups. This assay allowed to distinguish organisms belonging to the subgenus Viannia and identify L. (Leishmania) amazonensis and L. (L.) chagasi of the Leishmania subgenus. Of the 33 samples, PCR and nested PCR identified 91% of samples. After sequencing the PCR product of 26 samples, 16 were identified as L. (L.) amazonensis, the other 10 contain organisms belonging to the L. (Viannia) sub-genus. These results open a huge opportunity to study stored samples and promote relevant contributions to epidemiological studies.

DNA extraction from formalin-fixed laryngeal biopsies: Comparison of techniques

Conclusion: PCR-quality DNA could be extracted from formalin-fixed paraffin-embedded (FFPE) samples with amplicons of at least 390 bp. Paraffin removal was not a necessary step. Proteinase K digestion was as efficient as the commercial kit for DNA extraction with a lower cost. Objectives: To compare different DNA extraction protocols for FFPE samples and to describe the suitability of the extracted DNA for PCR reactions. Methods: For deparaffinization the following techniques were compared: alkaline heat, xylene, and no removal. For DNA extraction, proteinase K digestion and organic extraction were compared. A commercial extraction kit was included as standard. DNA quality was assessed by PCR amplification of the HFE gene, for amplicons of 208 and 390 bp. Results: Extraction with the commercial kit and proteinase K digestion were more efficient than other techniques, with no statistical difference between them for both amplicons. The proteinase K digestion buffer had a cost of U$ 0.2 per sample and the commercial kit of U$7 per sample.

Selective Paraffin Removal from Ethane/Ethylene Mixtures by Adsorption into Aluminum Methylphosphonate-α: A Molecular Simulation Study

Most adsorbent materials used for olefin/paraffin separation show preferential adsorption of the olefin. Recently, the material aluminum methylphosphonate polymorph alpha (AlMePO-alpha) was found to be able to selectively adsorb the paraffin instead of the olefin, from an ethyl chloride/vinyl chloride mixture (Herdes, C.; Valente, A.; Lin, Z.; Rocha, J.; Coutinho, J. A. P.; Medina, F.; Vega, L. F. Langmuir 2007, 23, 7299). However, several questions remain still open regarding the reasons for this selective paraffin adsorption, as well as the suitability of AlMePO-alpha as adsorbent for other olefin/paraffin separations. In this work, the adsorption of ethane/ethylene mixtures by AlMePO-alpha is investigated using grand canonical Monte Carlo simulations in order to determine the effect of molecular interactions, size, and shape on the selective adsorption. For this purpose three different force fields have been used for the fluids, investigating the effect of the molecular details of the fluid on the adsorption behavior. All three force fields gave the same qualitative behavior. It was found that AlMePO-alpha is also able to selectively adsorb the paraffin from ethane/ethylene mixtures. Moreover, ethane molecules arrange exactly in the same way in the adsorbent material as ethyl chloride, with the methyl groups directed toward each other, although ethane has much smaller dynamic diameter compared to ethyl chloride. Therefore, a key factor determining the selectivity is found to be the molecular interaction between the methyl group of AlMePO-alpha and the methyl group of the paraffin.

Vertical Transmission ofPneumocystis jiroveciiin Humans

Vertical Transmission of<i>Pneumocystis jirovecii</i>in Humans

Direct Analysis and MALDI Imaging of Formalin-Fixed, Paraffin-Embedded Tissue Sections

Formalin fixation, generally followed by paraffin embedding, is the standard and well-established processing method employed by pathologist. This treatment conserves and stabilizes biopsy samples for years. Analysis of FFPE tissues from biopsy libraries has been, so far, a challenge for proteomics biomarker studies. Herein, we present two methods for the direct analysis of formalin-fixed, paraffin-embedded (FFPE) tissues by MALDI-MS. The first is based on the use of a reactive matrix, 2,4-dinitrophenylhydrazine, useful for FFPE tissues stored less than 1 year. The second approach is applicable for all FFPE tissues regardless of conservation time. The strategy is based on in situ enzymatic digestion of the tissue section after paraffin removal. In situ digestion can be performed on a specific area of the tissue as well as on a very small area (microdigestion). Combining automated microdigestion of a predefined tissue array with either in situ extraction prior to classical nanoLC/MS-MS analysis or automated microspotting of MALDI matrix according to the same array allows the identification of both proteins by nanoLC-nanoESI and MALDI imaging. When adjacent tissue sections are used, it is, thus, possible to correlate protein identification and molecular imaging. These combined approaches, along with FFPE tissue analysis provide access to massive amounts of archived samples in the clinical pathology setting.

A Role for the G12 Family of Heterotrimeric G Proteins in Prostate Cancer Invasion

Many studies have suggested a role for the members of the G12 family of heterotrimeric G proteins (Galpha12 and Galpha13) in oncogenesis and tumor cell growth. However, few studies have examined G12 signaling in actual human cancers. In this study, we examined the role of G12 signaling in prostate cancer. We found that expression of the G12 proteins is significantly elevated in prostate cancer. Interestingly, expression of the activated forms of Galpha12 or Galpha13 in the PC3 and DU145 prostate cancer cell lines did not promote cancer cell growth. Instead, expression of the activated forms of Galpha12 or Galpha13 in these cell lines induced cell invasion through the activation of the RhoA family of G proteins. Furthermore, inhibition of G12 signaling by expression of the RGS domain of the p115-Rho-specific guanine nucleotide exchange factor (p115-RGS) in the PC3 and DU145 cell lines did not reduce cancer cell growth. However, inhibition of G12 signaling with p115-RGS in these cell lines blocked thrombin- and thromboxane A2-stimulated cell invasion. These observations identify the G12 family proteins as important regulators of prostate cancer invasion and suggest that these proteins may be targeted to limit invasion- and metastasis-induced prostate cancer patient mortality.

The Roles of Two Clip Domain Serine Proteases in Innate Immune Responses of the Malaria Vector Anopheles gambiae

The malaria vector Anopheles gambiae is capable of multiple immune responses against Plasmodium ookinetes. Accumulating evidence in several insect species suggests the involvement of serine protease cascades in the initiation and coordination of immune responses. We report molecular and reverse genetic characterization of two mosquito clip domain serine proteases, CLIPB14 and CLIPB15, which share structural similarity to proteases involved in prophenoloxidase activation in other insects. Both CLIPs are expressed in mosquito hemocytes and are transcriptionally induced by bacterial and Plasmodium challenges. Functional studies applying RNA interference revealed that both CLIPs are involved in the killing of Plasmodium ookinetes in Anopheles. Studies on parasite melanization demonstrated an additional role for CLIPB14 in the prophenoloxidase cascade. We further report that both CLIPs participate in defense toward Gram-negative bacteria. Our findings strongly suggest that clip domain serine proteases serve multiple functions and play distinctive roles in several immune pathways of A. gambiae.

Paraffin removal from tissue sections for digestion and PCR analysis.

Paraffin removal from tissue sections for digestion and PCR analysis.

A Fundamental Study on Vietnamese Crude Oil Refining. Normal Paraffin Separation and Utilization.

Vietnamese crude oil such as Bach Ho has a high paraffin content, and it must be processed in a different manner from ordinary crudes to obtain maximum fuel products. In this paper, we discuss the following: characteristics of Vietnamese crudes and distillates; experimental data on normal paraffin removal from distillates (mainly gas-oil fraction) to meet product specifications; and the applications of recovered normal paraffins. Design analysis and economics study are also conducted to illustrate the feasibility of the projects. In order to produce on-spec gas-oil from Bach Ho crude, normal paraffin extraction process using molecular sieve has been selected, and LAB (Linear Alkyl Benzene) and SAS (Sodium Alkane Sulfonate) productions from the recovered normal paraffins are discussed.

Staining Paraffin Embedded Sections of Scald of Barley before Paraffin Removal

Staining of paraffin embedded sections with periodic acid-Schiff reagent and fast green before paraffin removal resulted in differentiation of barley seed and leaf tissue from fungal structures of Rhynchosporium secalis. Crystal violet, toluidine blue O and aniline blue also successfully stained fungal structures of R. secalis in barley leaf tissues. Staining of embedded sections before paraffin removal allows simple processing of a series of sections, saves time and reduces solvent consumption.

Comparison of Deparaffinization Agents for an Automated immunostainer

AbstractTwo xylene substitutes (a terpene and an isoparaffinic hydrocarbon) were compared to xylene as the deparaffinization agent in an automated immunostainer. Human kidney tissue was stained for cytokeratin with amino-ethyl carbazole as the chromogen. There was no discernable difference in either staining intensity, background staining, or effectiveness of paraffin removal among the 3 clearing agents. There also were no differences among these parameters when the slides were reviewed after 8 mo storage in the dark, with the exception of the staining intensity, whichdiminishedequally withal1 clearing agents. The occupational, environmental, and regulatory aspects of these 3 clearing agents are discussed. (The J Histotechnol 16:367, 1993)

Starch Removal from Potato Tuber Sections

Heating plant sections at 90 C with 0.5% aqueous ammonium oxalate is required to remove pectins. When applied to tissues rich in starch such as potato, this step produces heavy dextrinization of the starch which hinders subsequent evaluation of the extinction values of the cell walls. To overcome this a method has been devised to brush away the starch granules from the sections with a thin paint brush, just after paraffin removal by xylene. The slide is then processed as usual: pectins are removed by heat treatment, cell walls are stained with PAS and the stain intensity can be evaluated by photometry.

Formation Damage Related to Hot Oiling

Summary Hot oil has been used to remove paraffin deposits almost as long as oil has been produced. It is still the most widely used procedure for paraffin removal in use today because of its relative simplicity of application, immediate results, and low cost per application. These apparent benefits have obscured the damage that hot oil can cause when used to clean downhole production equipment. Formation damage caused by hot oiling is related to the physical characteristics of the oil used, the source of the oil, the formation temperature, and the hot-oil process. Potential problems are discussed and suggestions made to minimize or to eliminate them. Laboratory tests are presented for determining whether a crude will cause formation damage during hot oiling. Case histories of successful cleaning of hot-oil formation damage are also given.

Temperature profiles during heated liquid injection

An analytical model for heated liquid injection into an oil well has been developed. The model couples heat convection and conduction in the well annulus with transient radial heat conduction in the surrounding formations to calculate injected fluid temperature as a function of time and depth. The model is verified by comparison of simulated temperature profiles with field case studies of hot oil injection for paraffin removal. A method is provided for calculation of the maximum depth at which annular injection of heated liquid can be used for paraffin removal.

Well- and Formation-Damage Removal With Nonacid Fluids

Well damage, in the form of various impediments to fluid flow through the formation rock, can reduce or completely eliminate production or injection rates of the well. Prevention and/or removal of well damage have consequently become a major field of study and concentration within the petroleum industry. Although acid solutions have been used for well-damage removal since before the turn of the century, there are situations in which acid is not the best choice for damage removal. The most obvious condition under which acid is not applicable is where the damaging mechanism is not appreciably soluble in acid solutions. Use of acid here would be a waste of time and material.