Background: Novel antidepressant drugs are increasingly used by women of child bearing age. However, potentially harmful effects on fetus and newborn remain unknown. Methods: Case report and literature review. Results: We present preterm twins whose mother was treated with venlafaxine, a nonselective serotonin reuptake inhibitor, throughout pregnancy until delivery. The twins developed neonatal necrotizing enterocolitis. Conclusion: The question whether there might be a correlation between maternal serotonin reuptake inhibitor therapy and neonatal necrotizing enterocolitis is discusse

Treichel, Markus

Schwendener Scholl, Katharina

Kessler, Ulf

Joeris, Alexander

Nelle, Mathias

JOURNAL OF ENGINEERING & PROCESSING MANAGEMENT

RERO DOC Digital Library

World J Pediatr, Vol 5 No 1 . February 15, 2009 .  www.wjpch.com65NEC following maternal venlafaxine treatmentCase reportAuthor Affi liations: Department of Neonatology (Treichel M, Schwendener Scholl K, Nelle M) and Department of Surgical Pediatrics (Kessler U, Joeris A), Children's Hospital, University of Berne, Berne, SwitzerlandCorresponding Author: Ulf Kessler, Department of Surgical Pediatrics, Inselspital, 3010 Berne, Switzerland (Tel: +41 31 6329223; Fax: +41 31 6329292; Email: ulf.kessler@insel.ch)doi:10.1007/s12519-009-0013-6©2009, World J Pediatr. All rights reserved.Background: Novel antidepressant drugs are increasingly used by women of child bearing age. However, potentially harmful effects on fetus and newborn remain unknown.Methods: Case report and literature review.Results: We present preterm twins whose mother was treated with venlafaxine, a nonselective serotonin reuptake inhibitor, throughout pregnancy until delivery. The twins developed neonatal necrotizing enterocolitis.Conclusion: The question whether there might be a correlation between maternal serotonin reuptake inhibitor therapy and neonatal necrotizing enterocolitis is discussed.World J Pediatr 2009;5(1):65-67Key words: antidepressive agents;                   necrotizing enterocolitis;                   nonselective serotonin reuptake inhibitor;                    pregnancy;                   venlafaxineIntroductionVenlafaxine (Efexor®) is a nonselective serotonin reuptake inhibitor (nSSRI). It is supposedly a potent serotonin and norepinephrine reuptake inhibitor and a weak inhibitor of dopamine reuptake. It is commonly used in the therapy of depression and panic disorders. Venlafaxine is metabolized in the liver and is mainly eliminated by the kidneys. In adults the average elimination half life of venlafaxine is 5 hours and that of its active metabolite O-desmethylvenlafaxine 11 hours. In neonates the elimination half life is unknown.Reproduction studies in rats and rabbits given venlafaxine at doses up to 2.5 to 4 times the maximum recommended human daily dose did not reveal teratogenicity.[1] When rats were given the maximum dose during pregnancy through weaning, there was a decrease in pup weight and an elevated number of stillbirths and pup deaths during the fi rst 5 days of lactation.[1]Einarson et al[2] compared 150 pregnant women using venlafaxine to 150 women exposed to selective serotonin reuptake inhibitors (SSRIs) and 150 women exposed to nonteratogenic agents. There were no signifi cant differences in the rate of abortions, gestational age at birth, live births, birth weights, and major malformations. Withdrawal symptoms of newborn infants after exposure to SSRI and nSSRI are well-described.[3,4]Case reportWe present dichorial diamniotic twins who both developed necrotizing enterocolitis (NEC) on the 6th day of life. They were delivered by cesarean section at a gestational age of 33+2 weeks due to persistent vaginal bleeding and contractions secondary to placenta praevia marginalis. The fi rst two trimesters of pregnancy were uneventful. The mother was hospitalized for the fi rst time in the 31st week of pregnancy because of vaginal bleeding. Because of an infection with Chlamydia trachomatis, she was treated with azithromycin (zithromax®) for 4 days. She received betamethasone (celestone chondrose®) 12 mg twice in 24 hours to enhance fetal lung maturity. Furthermore the mother was treated with venlafaxine (Efexor®) throughout pregnancy at a single dosage of 75 mg per day until delivery because of depression.Twin A was born with a birthweight of 1700 g (15th percentile). He had Apgar scores of 6 at 1 minute, 7 at 5 minutes, and 8 at 10 minutes. The umbilical arterial cord pH was 7.22.The baby was intubated in the fi rst hour of life Is there a correlation between venlafaxine therapy duringpregnancy and a higher incidence of necrotizing enterocolitis?Markus Treichel, Katharina Schwendener Scholl, Ulf Kessler, Alexander Joeris, Mathias NelleBerne, SwitzerlandWorld J Pediatr, Vol 5 No 1 . February 15, 2009 . www.wjpch.com66World Journal of PediatricsCase reportbecause of respiratory insuffi ciency and supplemental oxygen requirement. He was extubated successfully on the second day of life. Feeding was started on the fi rst postnatal day with maltodextrin® and breast milk. Enteral feeds with breast milk and preterm formula were gradually increased by about 20 ml/kg per day until the feeding volume reached 100 ml/kg per day on the 5th postnatal day.On the 6th day of life, the child showed signs of necrotizing enterocolitis (NEC) with abdominal distension and bloody stool. Conservative management consisted of withholding oral feeds for 3 days and intravenous antibiotics, amikacine and amoxicilline for 5 and 7 days, respectively. Apart from clostridium diffi cile toxin in the stool specimen, blood and stool cultures were negative. The abdominal X-ray revealed no signs of pneumoperitoneum or pneumatosis intestinalis (Bell's stage I). Feeds were well-tolerated afterwards. Twin B was born with a birthweight of 1980 g (30th percentile). He had Apgar scores of 4 at 1 minute, 5 at 5 minutes, and 8 at 10 minutes. The umbilical arterial cord pH was 7.24.Twin B was also ventilated on his fi rst day of life for respiratory insuffi ciency and supplemental oxygen requirement. Enteral feeds were also started on the fi rst day of life with maltodextrin® and breast milk. As in twin A, enteral feeds with breast milk and preterm formula were gradually increased by about 20 ml/kg per day until the feeding volume reached 80 ml/kg per day on the 5th postnatal day.On the 6th day, he developed abdominal distension, signs of peritonitis, bloody stool and gastric residuals. Conservative therapy with intravenous antibiotics (amikacine and amoxicilline) and stop of oral feeding was initiated. The abdominal X-ray showed intestinal pneumatosis, but no pneumoperitoneum (Bell's stage IIb). Because of further clinical deterioration under conservative management he underwent surgery on the 10th day of life. A long segment bowel necrosis with several perforations was found. Terminal ileum, right colon and the proximal transverse colon were resected, and enterostomy was performed. Culture of peritoneal fl uid, blood and stool remained negative. Feeding was started on the third postoperative day. On the 22nd day of life the baby had to undergo a second operation because of stomal stenosis. The stoma was closed at the age of fi ve months when he weighed 3000 g. At laparotomy we found colonic stenosis. At several levels a complete luminal obliteration of the remaining transverse colon and of the proximal part of the descending colon was seen and confi rmed by histological examination. The remaining transverse and proximal descending colons were resected and an anastomosis between ileum and descendent colon was created. The postoperative course was uneventful and the patient was discharged 10 days after stoma closure.DiscussionWe presented dichorial diamniotic twins with a gestational age of 33+2 weeks who both developed necrotizing enterocolitis on the 6th day of life. Their mother was treated with venlafaxine, a nonselective serotonin reuptake inhibitor, throughout pregnancy until delivery. The question is whether therapy with venlafaxine during pregnancy is associated with a higher incidence of NEC or not. To date no clear association has been described in the literature, although neonatal withdrawal symptoms are well described.[3,4] Both twins required mechanical ventilation, although they had mild signs of hyaline membrane disease only. Surfactant therapy was not necessary and ventilatory requirements were moderate. It might be speculated that respiratory insuffi ciency could be secondary from maternal venlafaxine therapy. However only two cases of respiratory disease have been reported in association with venlafaxine treatment in adults.[5,6]We found a case report describing two term neonates whose mothers were treated with a selective serotonin reuptake inhibitor (paroxetine) throughout pregnancy.[7] The babies developed NEC on the 3rd and 4th day of life respectively. The uncommon occurrence of NEC in term neonates raises the question of whether serotonin reuptake inhibitors, selective or not, increase the risk for microcirculatory failure, possibly causing NEC. SSRI reduces platelet serotonin by inhibiting its uptake. This occasionally causes platelet dysfunction and bleeding.[8] Stiskal et al[7] speculated that increased platelet function as a rebound phenomenon may predispose the neonate to a hypercoagulable state. Since platelet activating factor plays a central role in the pathogenesis of NEC, disturbed platelet function is supposed to be mainly involved in disease progression.[9] Cocaine functions as a reuptake inhibitor of norepinephrine and dopamine amongst other neurotransmitters. Maternal cocaine use causes vasoconstriction that can result in placental abruption and perinatal stroke.[10] This assumption is mainly based on case reports, but the study of Heier et al[10] reported that 17% of full-term infants born to cocaine users had evidence of cortical infarction. Furthermore, cocaine exposure can lead to diminished gut blood-supply and thereby contribute to the pathogenesis of World J Pediatr, Vol 5 No 1 . February 15, 2009 .  www.wjpch.com67NEC following maternal venlafaxine treatmentCase reportNEC. Two studies confi rmed the contributory role of cocaine abuse during pregnancy in the etiology, time of onset, and extent of neonatal NEC.[11,12]Nonselective serotonin reuptake inhibitors as venlafaxine may have a similar mechanism of action to cocaine. It might be speculated that the inhibition of norepinephrine reuptake causes vasoconstriction in the intestine and hence ischemia that can lead to necrosis.In the present case, prematurity certainly is an independent and essential risk factor for NEC. The correlation between enterocolitis and the venlafaxine therapy is speculative but possible and should be kept in mind when treating pregnant women and particularly when caring for newborns exposed to venlafaxine in utero.Funding: None.Ethical approval: Not needed.Competing interest: None declared.Contributors: Treichel M wrote the main body of the article under the supervision of Schwendener Scholl K and Kessler U. Kessler U and Joeris A provided advice on medical aspects. Nelle M is the guarantor.References1 Product information. Effexor® (venlafaxine hydrochloride) Tablets. Wyeth Pharmaceuticals Inc., 2008. www.wyeth.com/content/showlabeling.asp?id=99 (accessed July, 2008).2 Einarson A, Fatoye B, Sarkar M, Lavigne SV, Brochu J, Chambers C, et al. Pregnancy outcome following gestational exposure to venlafaxine: a multicenter prospective controlled study. Am J Psychiatry 2001;158:1728-1730.3 Costei AM, Kozer E, Ho T, Ito S, Koren G. Perinatal outcomes following third trimester exposure to paroxetine. Arch Pediatr Adolesc Med 2002;156:1129-1132.4 De Moor RA, Mourad L, ter Haar J, Egberts AC. Withdrawal symptoms in a neonate following exposure to venlafaxine during pregnancy. Ned Tijdschr Geneeskd 2003;147:1370-1372.5 Melien O, Skaali T, Myhr K, Brors O. Venlafaxine and asthma. Nord J Psychiatry 2005;59:538-540.6 Turner RC, Nelson JE, Roberts BT, Gillam DM. Venlafaxine associated interstitial penumonitis. Pharmacotherapy 2005;25: 626-629.7 Stiskal JA, Kulin N, Koren G, Ho T, Ito S. Neonatal paroxetine withdrawal syndrome. Arch Dis Child Fetal Neonatal Ed 2001;84:F134-135.8 Nair GV, Gurbel PA, O'Connor CM, Gattis WA, Murugesan SR, Serebruany VL. Depression, coronary events, platelet inhibition and serotonin reuptake inhibitors. Am J Cardiol 1999;84:321-323.9 Muguruma K, Gray PW, Tjoelker LW, Johnston JM. The central role of PAF in necrotizing enterocolitis development. Adv Exp Med Biol 1997;407:379-382.10 Heier LA, Carpanzano CR, Mast J, Brill PW, Winchester P, Deck MD. Maternal cocaine abuse: the spectrum of radiologic abnormalities in the neonatal CNS. AJNR Am J Neuroradiol 1991;12:951-956.11 Lopez SL, Taeusch HW, Findlay RD, Walther FJ. Time of onset of necrotizing enterocolitis in newborn infants with known prenatal cocaine exposure. Clin Pediatr (Phila) 1995;34:424-428.12 Czyrko C, Del Pin CA, O'Neill JA Jr, Peckham GJ, Ross AJ 3rd. Maternal cocaine abuse and necrotizing enterocolitis: outcome and survival. J Pediatr Surg 1991;26:414-418.Received September 24, 2007Accepted after revision May 7, 2008

Is there a correlation between venlafaxine therapy during pregnancy and a higher incidence of necrotizing enterocolitis?

Prrenjas clay mineral is found in southeast Albania and has a high content on bentonite. The influence of the sulphuric acid activation on the composition, structure and surface properties of Prrenjas clay mineral is investigated in this study by means of elemental chemical analysis, X-Ray Diffractometry, IR Spectroscopy and gas adsorption-desorption measurement. H&nbsp;2SO&nbsp;4&nbsp;concentrations of 0.143 M, 0.232 M, 0.371 M, 0.537 M, 0.734 M, 0.927 M and 1.456 M were used in the treatment of samples. The treatment by increasing the acid concentration brings the leaching of Al&nbsp;3+, Fe&nbsp;2+, Mg&nbsp;2+&nbsp;from the clay structure. The specific surface area and the pore volume of the clay samples increases respectively from 83 m&nbsp;2/g and 0.069 cm&nbsp;3/g for the untreated clay to 420 m&nbsp;2/g and 0.384 cm&nbsp;3&nbsp;/g for the clay mineral treated with 1.456 M H&nbsp;2SO&nbsp;4&nbsp;solution. New mesopores were created during the acid activation mainly in the range of 2 – 8 nm. For the samples treated with 0.927 M and 1.456 M solutions the increase in specific surface area and pore volume is very high. The cationic exchange capacity decreases steadily with the concentration of H&nbsp;2SO&nbsp;4&nbsp;used for the treatment

Mele, A.

Taraj, K.

Korpa, A.

Journal of Engineering & Processing Management (EPM)

_____________________________________________________________________________________ Journal of Engineering & Processing Management|  37      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa DOI: 10.7251/EEMEN1507037M UDK: 552.527  Scientific paper  ACID ACTIVATION OF PRRENJAS CLAY MINERAL  Altin Mele1, Krenaida Taraj2, Arjan Korpa1 altin.mele@fshn.edu.al  1University of Tirana, Faculty of Natural Sciences, 1016 Tirana, Albania    2Albanian University, Rruga “Kajo Karafili”, Faculty of Medicine, 1016 Tirana, Albania   Abstract Prrenjas clay mineral is found in southeast Albania and has a high content on bentonite. The influence of the sulphuric acid activation on the composition, structure and surface properties of Prrenjas clay mineral is investigated in this study by means of elemental chemical analysis, X-Ray Diffractometry, IR Spectroscopy and gas adsorption-desorption measurement. H2SO4 concentrations of 0.143 M, 0.232 M, 0.371 M, 0.537 M, 0.734 M, 0.927 M and 1.456 M were used in the treatment of samples. The treatment by increasing the acid concentration brings the leaching of Al3+, Fe2+, Mg2+ from the clay structure. The specific surface area and the pore volume of the clay samples increases respectively from 83 m2/g and 0.069 cm3/g for the untreated clay to 420 m2/g and 0.384 cm3/g for the clay mineral treated with 1.456 M H2SO4 solution. New mesopores were created during the acid activation mainly in the range of 2 – 8 nm. For the samples treated with 0.927 M and 1.456 M solutions the increase in specific surface area and pore volume is very high. The cationic exchange capacity decreases steadily with the concentration of H2SO4 used for the treatment. Keywords: clay mineral, acid activation, surface properties  1. INTRODUCTION Clay minerals are natural products of a wide range of applications. Their surface properties as specific surface area (SBET) and pore volume (V) and the cation exchange capacity (CEC) are the main parameters promoting their broad application in many industries. Clay minerals are use as catalysts [1 -3], catalyst carriers [4 – 6] and also in the beverage technology [7].     _____________________________________________________________________________________ Journal of Engineering & Processing Management|  38      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa  Nanotechnology, environment protection and water purification are promising future application fields of clay minerals. Bentonites are use in their natural or modified form (after acid, alkali, organic or thermal treatment). The acid modification, known as acid activation, has been investigated by several authors using hydrochloric acid [8-11] or sulfuric acid [12-15], to change the surface properties and smectite structure of the bentonites influencing their adsorption and catalytic properties [8,12].   This study was focused on the optimization of the sulfuric acid activation process in order to improve the surface properties of the Prrenjas clay mineral by preserving the CEC.    2. EXPERIMENTAL PART  2.1. Materials and methods Clay mineral from Prrenjas region in southeast Albania (bentonite) were treated with sulfuric acid (96%, Fluka) solutions of different molar concentrations of 0.143 M, 0.371 M, 0.734 M, 0.927 M and 1.456 M. The impurities were separated by decantation. Typically, 10 g of bentonite were dispersed in 1 L of distilled water and left to precipitate for 24 h. A fraction was separated, which corresponds to 2/3 of the height of the upper limit and left to dry in air. Such prepared bentonites were labeled P/M, P denote Prrenjas bentonite whereas M is the molarity of H2SO4, respectively (P/0.143, P/0.371, P/0.734, P/0.927 and P/1.456).  2.2. Acid activation For the H2SO4 acid treatment, 5 g of previously purified Prrenjas bentonite was dispersed in 50 mL of 0.143 M, 0.371 M, 0.734 M, 0.927 M and 1.456M H2SO4. The dispersion was heated for 3 hours at 90ºC under stirring as shown in the figure 1 and flushed with distilled water to a negative reaction to the sulfate ion, which was checked by BaCl2. The bentonites were dried at room temperature.  2.3. Characterization Chemical analyses were performed second the ASTM C114 standard [16], where the procedures for the determination of the oxides SiO2, Al2O3, Fe2O3, MgO, CaO, SO3 are described. Cation exchange capacity (CEC) was determined by the methylene blue (MB) adsorption method. For that 100 cm3 of distilled water and 0.5 g dried clay mineral are mixed under stirring in an Erlenmeyer flask. The dispersion is titrated with a MB 12.5 mM solution and MB cation is exchanged for the other cations in between of the clay layers. The equilibrium is controlled through the color of solution in contact with the clay as described in detail in [17].  _____________________________________________________________________________________ Journal of Engineering & Processing Management|  39      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa  The bentonite mineral composition was checked by X-ray powder diffraction (XRD) employing the SIEMENS D5000 automated system. The diffractograms were recorded using Cu Kα = 1.5406 Å radiation, setting the current of 20 mA and voltage of 35 kV (Ni filter). X-ray powder diagrams were collected in the 2θ range from 3 to 80º.  FT-IR spectra were recorded on a Thermo Scientific Nicolet 6700 (ATR) in the 4000–400 cm−1 region. Specific surface area tests were undertaken by determining the adsorption and desorption nitrogen isotherms at liquid nitrogen temperature (−196ºC). Before measurement, the sample was degassed at 120ºC and vacuumed over 24 hours. The achieved vacuum was measured with a Pirani vacuum gauge (measurement range 0.001 − 1 mbar). The analysis entailed determination of the sample specific surface area using the BET equation. Pore volume was determined based on the Gurwitsch’s rule, from the volume of liquid nitrogen adsorbed at the equilibrium pressure p = 920 mbar in the adsorption isotherm.  3. RESULTS AND DISCUSSION  3.1. Variation of chemical composition with the H2SO4 activation Table 1 shows the chemical composition and CEC of untreated and treated bentonites with 0.143 M, 0.371 M, 0.734 M, 0.927 M and 1.456 M H2SO4 solutions. By increasing the sulfuric acid concentration there was an increase in SiO2 content. The bentonite activation caused an increase of the SiO2 content due to remobilization of octahedral cations [18]. Octahedral cations shifted into the solution while the silicon, owning to its insolubility, remained and increased its content with the H2SO4 concentration. The SiO2 to the sum of the other metal oxides ratio (SiO2/ƩMxOy) increases from 1.239 to 4.073. One can observe from these analyses that the increase of sulfuric acid molarity provoked flushing of the interlayer cations Ca2+ and Mg2+ whose positions are occupied by the H+ ions. With the raise of sulfuric acid concentration the clay mineral shows a gradual decrease of the cation exchange capacity (CEC) from 82.5 to 45.5 mmol(eq)/100 g.  Impact of acid on structural characteristics XRD of the Prrenjas clay mineral is shown in Figure 2. The clay mineral displays peaks belonging to the mineral montmorillonite and non-clay mineral quartz (Figure 2). Is shown that the sulfuric acid activation of bentonite caused evident structural changes. The intensity of the indexed peaks (001), (003) and (006) was reduced with the increase of H2SO4 concentration treatment with 6 M acid. The XRD showed gradual dissolving of the octahedral sheets by treatment with 0927 M and 1.456 M of H2SO4. The disappearance of the M (001) peak shows the exfoliation of the mineral.   _____________________________________________________________________________________ Journal of Engineering & Processing Management|  40      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa  The structural changes that evolve the Prrenjas clay mineral samples are monitored by FTIR spectroscopy (Figure 3). The spectra show changes in the 4000–400 cm−1 region as described in previous papers [1, 15, 19, 20]. Namely, the most intensive band at 977 cm-1 is attributed to Si–O stretching vibrations of the tetrahedral sheets, have not been affected by acid treatment. The band Si-O-Al (500 – 520 cm-1) is the most sensitive one indicating the remaining Al3+ in the octahedral sheets. It decreases steadily with the increase of acid concentrations showing the leaching of Al3+. The bands of the region 600 – 700 cm-1 shows vertical vibrations of cations (R-O-Si) in the octahedral sheets with (R = Al, Mg, Fe) and also disappears after treatment with high acid concentration. In 1632 cm-1 and its overtone in 3264 cm-1 (overlapped by adsorptions of other vibrations which forms a broad band 3700 – 3200 cm-1) there are vibrations of the water molecules of mineral. They becomes smaller with the increase of acid concentration because the mineral loses its hydrophilic cations. The adsorption in 3660cm-1 is explained by vibrations of OH groups coordinated cations of Fe2+, Al3+ and Mg2+, and almost disappears with the increasing acid concentration.    3.2. Impact of acid on the surface properties of Prrenjas clay mineral The adsorption isotherms given as a share of the adsorbed nitrogen in the function of the relative pressure (at −196ºC) are shown in Figure 4. The specific surface area of Prrenjas clay mineral rises with the increase of molarity of the H2SO4. Based on the presented adsorption isotherms, the specific surface area of untreated and treated clay samples was calculated using the BET equation. The obtained values are shown in Table 2. In Prrenjas clay mineral there is a considerable change in the specific surface area and porosity specially after the treatment with 0.927 M and 1.456 M H2SO4. Differences occur due to the change in the montmorillonite structure and the same changes were observed in the XRD and IR analyses.  4. CONCLUSION According to structural and textural characteristics, the Prrenjas clay mineral untreated or treated with H2SO4 acid, due to its large surface area, can be used as good adsorbents and catalysts in many industries. Acid activation increased the surface area of the clay samples examined up to 420 m2/g. With the change of the chemical composition, structural and textural characteristics of sheets, a high specific surface area was created and a low cation exchange capacity was observed. Acid processing caused a quick loss of exchangeable Ca2+ and Mg2+ from the solid phase.     _____________________________________________________________________________________ Journal of Engineering & Processing Management|  41      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa  Using higher concentration of acid than 0.734 M, the removal of further Mg2+ and Al3+ and Fe2+ from octahedral sites leads to an increase of amorphous Si. It was concluded that reducing the layer charge occurred with decreasing cation exchange capacity and follows an increase in specific surface area and pore volume with increasing acid concentration.      Figure 1. Schematic design of the acid activation appratus.           _____________________________________________________________________________________ Journal of Engineering & Processing Management|  42      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa   Figure 2. XRD diagrams of untreated Prrenjas clay mineral (top) and P/0.143, P/0.371, P/0.734, P/0.927 and P/1.456 M respectively in the top-down order. The letter M is for identifying the montomillonite peaks, the peak at 2θ=26º belongs to quartz impurities.   Figure 3. FT-IR spectra of the untreated (down) and H2SO4 treated Prrenjas clay mineral P/0.143, P/0.371, P/0.734, P/0.927, P/1.456 M respectively in the down-top order.      _____________________________________________________________________________________ Journal of Engineering & Processing Management|  43      Volume 7, No. 1, 2015 A. Mele, K. Taraj, A. Korpa   Figure 4. adsorption isotherms of nitrogen at T=77 K on untreated and H2SO4 activated Prrenjas clay mineral samples.  Table 1. Chemical composition (wt. %), ratio SiO2 to the sum of other metal oxides content and CEC (mmol(eq)/100 g) of untreated and H2SO4 treated Prrenjas clay mineral Clay mineral SiO2 Al2O3 Fe2O3 CaO MgO SO3 SiO2 / ƩMxOy CEC untreated 47.05 13.4 14.97 2.7 9.58 0.11 1.239 82.5 P/0.143 47.49 12.52 15.53 0.85 7.83 0.15 1.323 74.25 P/0.371  49.15 9.55 16.04 0.96 7.12 0.23 1.502 68.75 P/0.734  51.74 9.31 14.16 0.89 6.10 1.15 1.901 65.25 P/0.927 59.26 6.95 10.11 0.55 4.97 0.12 2.429 57 P/1.456 65.54 6.82 5.32 1.10 3.95 0.35 4.073 45.5  Table 2. Specific surface area and pore volume for untreated and H2SO4 treated Prrenjas clay mineral samples Prrenjas clay mineral samples Specific surface area (m2/g) Pore volume  (cm3/kg) untreated 83.75 69.27 P/0.143 110.4 86.2 P/0.371 200 128 P/0.734 265 200 P/0.927 380 325 P/1.456 420 384 _____________________________________________________________________________________ Journal of Engineering & Processing Management|  44      Volume 7, No. 1, 2015 REFERENCES  [1] Steudel, L.F. Batenburg, H.R. Fischer, P.G. Weidler, K. Emmerich, Appl. Clay Sci. 44, 2009, 105–115. [2]  J.M. Adams, Appl. Clay Sci. 2, 1987, 309–342. [3]  A. Vaccari, Appl. Clay Sci. 14, 1999, 161–198. [4]  W. Teng-You, P. Yuan-Feng, L. Guo-Qing, T. Zhang-Fa, X. Hui-Ning, Environ. Eng. Sci. 27, 2010, 531–535. [5] C.N. Rhodes, M. Franks, G.M.B. Parkes, D.R. Brown, J. Chem. Soc. Chem. Comm. 12, 1991, 804–807. [6]  C.N. Rhodes, D.R. Brown, J. Chem. Soc. Faraday Trans. 88, 1992, 2269–2274. [7]  G.E. Christidis, P.W. Scott, A.C. Dunham, Appl. Clay Sci. 12, 1997, 329–347. [8]  J. Ravichandran, B. Sivasankar, Clays Clay Miner. 45, 1997, 854–858. [9]  P. Komadel, D. Schmidt, J. Madejova, B. Čičel, Appl. Clay Sci. 5, 1990, 113–122. [10]  J. Madejova, J. Budjak, M. Janek, P. Komadel, Spectrochim. Acta A 54, 1998, 1397–1406. [11]  H. Palkova, J. Madejova, D. Righi, Clays Clay Miner. 51, 2003, 133–142. [12]  P. Komadel, M. Janek, J. Madejova, A. Weekes, C. Breen, J. Chem. Soc. Faraday Trans. 93, 1997, 4207–4210. [13]  C. Breen, J. Madejova, P. Komadel, J. Mater. Chem. 5, 1995, 469–474. [14]  H.N.M. Onal, Y. Sarikaya, Food Chem. 105, 2007, 156–163. [15]  B. Tyagi, C.D. Chudasama, R.V. Jasra, Spectrochim. Acta A 64, 2006, 273–278. [16]  ASTM Standard C114. http://www.astm.org/Standards/C114.htm [17]  Kahr, G. and F.T. Madsen. Applied Clay Sci., 9, 1995, 327-336. [18]  J.L. Venaruzzo, C. Volzone, M.L. Rueda, J. Ortiga, Micropor. Mesopor. Mater. 56, 2002, 73–80. [19]  V.C. Farmer (Ed.), The Infrared Spectra of Minerals, Mineralogical Society, London,1974, pp. 331–358. [20]  K. Emmerich, F.T. Madsen, G. Kahr, Clays Clay Miner. 47 (1999) 591–604.           

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ACID ACTIVATION OF PRRENJAS CLAY MINERAL

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Is there a correlation between venlafaxine therapy during pregnancy and a higher incidence of necrotizing enterocolitis?

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