Potential use of dry powder of Vossia cuspidata (Roxb.) Griff. rhizomes and leaves in methylene blue dye remediation

Phytoremediation is a promising, cost-effective, and eco-friendly process for wastewater treatment. Herein, the dry biomasses of Vossia cuspidata (Roxb.) Griff. leaves (PL) and rhizomes including aerial stems (PR) were used to effectively remediate methylene blue (MB) dyes. Interestingly, the adsorption uptake and removal efficiency of MB by PR were higher than those of PL; exceeding 97 and 91% in 35 and 25 min for 0.1 and 0.4 g/L MB, respectively. The MB diffusion within the PL and PR was insignificant and the adsorption kinetics was principally controlled by the surface MB-adsorbent interaction, as consistently approved by the pseudo-second order kinetic model. In addition, the adsorption increased rapidly with the plant dosage with high dependence on the initial MB concentration. Moreover, the impact of shaking speed on the adsorption was minor but temperature played a critical role where the highest efficiencies were recorded at 30 and 40 °C on PL (91.9%) and PR (93.3%), respectively. The best removal efficiencies were attained with PR at pH 6, but with PL at pH 8. The Temkin isotherm could perfectly simulate the experimental data (R2 > 0.97); suggesting a linear decrease of the adsorption heat of MB with the plant coverage.

Boosted formic acid electro-oxidation on platinum nanoparticles and "mixed-valence" iron and nickel oxides

The modification of Pt nanoparticles (nano-Pt, assembled electrochemically onto a glassy carbon (GC) substrate) with hybrid multivalent nickel (nano-NiO_x) and iron (nano-FeO_x) oxide nanostructures was intended to steer the mechanism of the formic acid electro-oxidation (FAO) in the desirable dehydrogenation pathway. This binary modification with inexpensive oxides succeeded in mediating the reaction mechanism of FAO by boosting reaction kinetics "electron transfer" and amending the surface geometry of the catalyst against poisoning. The sequence of deposition was optimized where the a-FeO_x/NiO_x/Pt/GC catalyst (where "a" denotes a post-activation step for the catalyst at -0.5 V in 0.5 mol L^-1 NaOH) reserved the best hierarchy. Morphologically, while nano-Pt appeared to be spherical (ca. 100 nm in average diameter), nano-NiO_x appeared as flowered nanoaggregates (ca. 56 nm in average diameter) and nano-FeO_x (after activation) retained a plate-like nanostructure (ca. 38 nm in average diameter and 167 nm in average length). This a-FeO_x/NiO_x/Pt/GC catalyst demonstrated a remarkable catalytic efficiency (125 mA mg_Pt^-1) for FAO that was ca. 12.5 times that of the pristine Pt/GC catalyst with up to five times improvement in the catalytic tolerance against poisoning and up to -214 mV shift in the FAO's onset potential. Evidences for equipping the a-FeO_x/NiO_x/Pt/GC catalyst with the least charge transfer resistance and the highest stability among the whole investigated catalysts are provided and discussed.

Tailor-designed nanowire-structured iron and nickel oxides on platinum catalyst for formic acid electro-oxidation

This investigation is concerned with designing efficient catalysts for direct formic acid fuel cells. A ternary catalyst containing iron (nano-FeOx) and nickel (nano-NiOx) nanowire oxides assembled sequentially onto a bare platinum (bare-Pt) substrate was recommended for the formic acid electro-oxidation reaction (FAOR). While nano-NiOx appeared as fibrillar nanowire bundles (ca. 82 nm and 4.2 μm average diameter and length, respectively), nano-FeOx was deposited as intersecting nanowires (ca. 74 nm and 400 nm average diameter and length, respectively). The electrocatalytic activity of the catalyst toward the FAOR depended on its composition and loading sequence. The FeOx/NiOx/Pt catalyst exhibited ca. 4.8 and 1.6 times increases in the catalytic activity and tolerance against CO poisoning, respectively, during the FAOR, relative to the bare-Pt catalyst. Interestingly, with a simple activation of the FeOx/NiOx/Pt catalyst at −0.5 V vs. Ag/AgCl/KCl (sat.) in 0.2 mol L⁻¹ NaOH, a favorable Fe²⁺/Fe³⁺ transformation succeeded in mitigating the permanent CO poisoning of the Pt-based catalysts. Interestingly, this activated a-FeOx/NiOx/Pt catalyst had an activity 7 times higher than that of bare-Pt with an ca. −122 mV shift in the onset potential of the FAOR. The presence of nano-FeOx and nano-NiOx enriched the catalyst surface with extra oxygen moieties that counteracted the CO poisoning of the Pt substrate and electronically facilitated the kinetics of the FAOR, as revealed from CO stripping and impedance spectra.

A FeOx/NiOx/Pt catalyst was recommended for formic acid electro-oxidation; the essential anodic reaction in direct formic acid fuel cells.

Propitious Dendritic Cu2O-Pt Nanostructured Anodes for Direct Formic Acid Fuel Cells

This study introduces a novel competent dendritic copper oxide-platinum nanocatalyst (nano-Cu₂O-Pt) immobilized onto a glassy carbon (GC) substrate for formic acid (FA) electro-oxidation (FAO); the prime reaction in the anodic compartment of direct formic acid fuel cells (DFAFCs). Interestingly, the proposed catalyst exhibited an outstanding improvement for FAO compared to the traditional platinum nanoparticles (nano-Pt) modified GC (nano-Pt/GC) catalyst. This was evaluated from steering the reaction mechanism toward the desired direct route producing carbon dioxide (CO₂); consistently with mitigating the other undesired indirect pathway producing carbon monoxide (CO); the potential poison deteriorating the catalytic activity of typical Pt-based catalysts. Moreover, the developed catalyst showed a reasonable long-term catalytic stability along with a significant lowering in onset potential of direct FAO that ultimately reduces the polarization and amplifies the fuel cell's voltage. The observed catalytic enhancement was believed to originate bifunctionally; while nano-Pt represented the base for the FA adsorption, nanostructured copper oxide (nano-Cu₂O) behaved as a catalytic mediator facilitating the charge transfer during FAO and providing the oxygen atmosphere inspiring the poison's (CO) oxidation at relatively lower potential. Surprisingly, moreover, nano-Cu₂O induced a surface retrieval of nano-Pt active sites by capturing the poisoning CO via "a spillover mechanism" to renovate the Pt surface for the direct FAO. Finally, the catalytic tolerance of the developed catalyst toward halides' poisoning was discussed.

Adsorption/Desorption of H2 and O2 at a p-Cr2O3 Surface: Electrical Conductivity Studies

The behaviour of H2 and O2 flows over a porous p-Cr2O3 pellet have been studied by means of an in situ electrical conductivity technique. Changes in the electrical conductivity associated with such gas flows were attributed to changes in the concentration of positively charged holes in the material studied. In the presence of an H2 flow, the electrical conductivity of the p-Cr2O3 surface first increased and then decreased sharply. The initial increase was attributed to the chemisorption of H2 leading to surface hydroxylation. The formation of O–H bonds during this process resulted in a decrease in the electron density at the surface and thereby increased the contribution of positively charged holes towards the total conductivity. In contrast, the subsequent sharp decrease in conductivity was explained by the elimination of chemisorbed oxygen which had originally been adsorbed dissociatively at the surface. During this process, elimination of chemisorbed oxygen atoms led to the presence of electrons in the chromia lattice which generated a sharp decrease in the hole concentration via an electron–hole recombination process. In an O2 atmosphere, the conductivity of the deoxygenated chromia increased exponentially to a maximum value and then decreased until it reached a value similar to that for stoichiometric chromia. The increase in conductivity observed in this case was assigned to the adsorption of oxygen on the chromia surface while the subsequent decrease was attributed to hydrogen desorption.

The kinetics of the four processes observed, i.e. hydrogen adsorption, oxygen desorption, oxygen adsorption and hydrogen desorption, have been analyzed.

Novel fuel blends facilitating the electro-oxidation of formic acid at a nano-Pt/GC electrode

This paper addresses the promoting effect of the electrooxidation of formic acid (FAO) at a nano-Pt/GC electrode in the presence of selected low molecular weight alcohols (R–OH) as blending components.

Single-layer closure of typhoid enteric perforation: Our experience

BACKGROUND

Typhoid enteritis is rare in developed countries. The increasing prevalence of typhoid fever with enteric perforation in our environment is alarming. Peritonitis follows enteric perforation due to typhoid enteritis. Surgical treatments and repair of the perforated areas due to typhoid enteritis varies between institutions with high mortality and morbidity.

MATERIALS AND METHODS

We retrospectively studied the effects of single versus double layer intestinal closure after typhoid enteric perforation with peritonitis in 902 pediatric patients from September 2007 to April 2012. All the patients underwent laparotomy after resuscitation and antibiotic cover. The patients were divided into two groups: group A (n = 454) double layer closure and group B (n = 448) single layer closure.

RESULTS

There were 554 males and 348 females with male to female ratio 1.6:1. Ages of the patients were three years to 14 years with mean age at eight years and mode at nine years. The following clinical outcomes were recorded: burst abdomen 38 (8.3%) vs 3 (0.6%), enterocutaneous fistula formation 52 (11.4%) vs 8 (1.7%), superficial wound infection 215 (47.3%) vs 91 (20.3%), ligature fistula 13 (2.8%) vs 7 (1.5%), mean length of 29.4 ± 7.8 vs 45.3 ± 11.6.

CONCLUSION

Our results showed that single layer closure of the perforated ileum due to typhoid enteric perforation with peritonitis in children was effective by reducing complication rates.

Multiple familial trichoepithelioma: a case report and review of literature

OBJECTIVE

Multiple familial trichoepitheliomas are rare autosomal dominant skin disease that is rarely reported from this part of the world. The lesions resemble other types of skin diseases that present with papules and nodules.

PATIENT AND METHOD

This is case report of a patient who presented with multiple facial papules and nodules. He wanted treatment to improve his facial (cosmetic) appearance.

RESULTS

A 36 year old single male with a 25 years history of multiple facial papules and nodules. Similar lesions were present in other members of the family. He had several treatments including that for leprosy. Histologically the lesions showed keratinized stratified squamous epithelium overlying proliferating packets of basoloid cells with hyper chromatic nuclei, along with several keratin horn cysts and moderate stroma infiltrate of chronic inflammatory cells. Based on the history and the histology a diagnosis of multiple familial trichoepithelioma was made.

CONCLUSION

For a diagnosis of multiple familial trichoepithelioma to be made in patients presenting with multiple facial papules and nodules a high index of suspicion is needed. This is more so if there is a history of similar lesions in the family.

Expression of cyclooxygenase-2 and 12-lipoxygenase in human breast cancer and their relationship with HER-2/neu and hormonal receptors: impact on prognosis and therapy

BACKGROUND

A number of studies have shown over-expression of cox-2 in breast cancer. Also it has been recorded that human breast cancer expresses high level of cox-2 and 12-lipoxygenase which may be beneficial in future therapy plan for those patients.

AIMS

The present study aims to examine the level of transcripts of cox-2 and 12-lipoxygenase in Egyptian breast cancer patients and to compare between the expressions of both enzymes and TNM staging, hormone receptors status (including estrogen and progesterone) and HER2/neu expression.

MATERIALS AND METHODS

Total cellular RNA was extracted from 64 frozen tissue samples of breast carcinoma and their corresponding normal adjacent tissues. Cox-2 and 12-lipooxygenase expressions were detected using RT-PCR. Hormonal receptors as well as HER2/neu were detected immuno-histochemically for each patient.

RESULTS

About 47 and 62.5% of carcinoma samples showed over-expression of cox-2 and 12-lipooxygenase respectively as compared to their corresponding normal tissues. The results revealed that cox-2 significantly associated with TNM staging (P = 0.0047) and hormonal receptors status (P = 0.0201). The relationship between cox-2 and HER2/neu expression was close to a significant value (P = 0.0747). 12-lipooxygenase showed only significant association with TNM staging (P = 0.0076). Neither hormonal receptors nor HER2/neu showed significant association with this enzyme.

CONCLUSION

Elevated levels of cox-2 and 12-lipoxygenase expression were detected in human breast cancer. Also, the results revealed that cox-2 and 12-lipooxygenase mRNA expressions are associated with TNM staging in human breast cancer. Furthermore, there is an inverse association between cox-2 expression and hormonal receptor status. This observation may drive us to the possible role of those two enzymes in determining the plan of therapy of breast cancer patients.

Fabrication and Electrochemical Application of Three-Dimensional Gold Nanoparticles: Self-Assembly

Multilayers film of nanostructured citrate-stabilized gold particles (AuNPs) has been fabricated based on the layer-by-layer (LBL) technique using a self-assembled monolayer of 1,4-benzenedimethanethiol (BDMT). The formation of AuNPs and BDMT self-assemblies as alternative multilayers was confirmed by transmission electron microscopy (TEM), X-ray photoelectron spectroscope (XPS), and quartz crystal microbalance (QCM). The formation of uniform AuNP layers with an average monolayer thickness of 5-6 nm was obvious in the TEM images. The existence of BDMT molecules as cross linkers for the AuNPs' layers was proved by XPS measurements. The greater affinity of AuNPs' layers to bind BDMT molecules in comparison with the bare Au bulk electrode was revealed by QCM measurements. Electrochemically, the AuNPs' layers on the electrode surface did not only catalyze the reduction of oxygen (ca. 100-mV positive shift of the reduction peak potential compared with that at the bare Au bulk electrode) but also showed a fascinating nature of working as a renewed activated-electrode surface; a zigzag response was observed for oxygen reduction during alternative immobilization of BDMT and the AuNP layer. The self-assembly of a new AuNPs layer restored the catalytic activity that was entirely blocked by the preceding BDMT layer.

Cervical priming prior to operative hysteroscopy: a randomized comparison of laminaria versus misoprostol

BACKGROUND

We aimed to compare efficacy of intravaginal misoprostol versus endocervical laminaria tents prior to operative hysteroscopy in selected cases.

METHODS

A total of 144 patients with diagnosed intrauterine lesions scheduled for operative hysteroscopy were randomly allocated to two groups according to method of cervical priming prior to the procedure. Misoprostol 200 microg was inserted into the posterior fornix of the vagina for patients in group A (n=72), while laminaria tents were inserted intracervically in group B patients (n=72).

RESULTS

Both methods were effective for cervical dilatation with a mean cervical diameter of 7.5+/-1.2 and 7.6+/-1.2 mm respectively. There was no significant difference in the mean cervical diameter or the time required for cervical dilatation (51.6 versus 51.4 s respectively). In contrast, there was a significant difference between the groups with respect to the insertion difficulty and in doctors' and patients' assessments of the procedure.

CONCLUSIONS

Both misoprostol and laminaria were equally effective in inducing proper cervical priming prior to operative hysteroscopy with minimal time of cervical dilatation. Nevertheless, misoprostol may be superior due to easy application, reduced cost, and patient convenience and acceptability.

Incidence of spontaneous abortion in Bahrain before and after the Gulf War of 1991

OBJECTIVES

To determine the incidence of spontaneous abortions in the 5 years before and 5 years after the Gulf War of 1991 and to explore the possible causes that may have affected these changes. To analyze the clinical types, associated medical problems, morbidity, length of hospital stay and mortality rate of abortions.

DESIGN

Retrospective study for the period starting on 1 January 1987-31 December 1996.

SUBJECTS

The study involved 14,850 cases of abortions admitted into Salmaniya Medical complex during this period.

SETTING

The Salmaniya Medical Complex (SMC) is the main referral hospital in Bahrain.

METHODS

Analysis of medical records of patients admitted with diagnosis of abortion during this period.

RESULTS

By comparing the incidence of abortions in the 5 years before (1 January 1987-31 December 1991) and the 5 years after (1 January 1992-31 December 1996) the Gulf War a significant rise was observed--starting from 1992, reaching a peak in 1994, which then began to decline in 1996.

CONCLUSION

Several published reports from Iraq, Kuwait and now from Bahrain are suggestive of an increase in the incidence of abortion and adverse outcome of pregnancy after the Gulf War of 1991. The mechanism is not clear, i.e. whether this is affected by toxicity acquired through the food chain, the oil spillage, smoke pollution resulting from the burning of the Kuwaiti oil fields or stress and anxiety caused by the war.

Sickle cell disease in Bahrain: coexistence and interaction with glucose-6-phosphate dehydrogenase (G6PD) deficiency

The object was to determine the frequency of glucose-6-phosphate dehydrogenase in Bahraini individuals with HbS as compared to those without HbS. Haemolysates of erythrocytes from 310 Bahraini individuals attending Health Centres were obtained, electrophoresed on cellulose acetate at PH 8.2-8.6, and stained for G6PD. HbS was present in 125 individuals (study group) and in 185 only HbA was present (control group). G6PD deficiency (very low to undetectable) was identified in 59 samples (47 per cent) of the study group and 35 (19 per cent) of the control group. A positive correlation between G6PD deficiency and HbS is present in Bahraini individuals tested. This is similar to the situation in the Eastern Province of Saudi Arabia. We speculate that the observation could be explained on the basis of historic endemicity of Falciparum malaria in both regions on the East coast of the Saudi Peninsula.

Biochemical and electrophoretical studies of the effect of some chemosterilants on theenzymes of aedes aegypti (L.) larvae

In vivo effect of standard and prospective chemosterilants on some enzymes is reported. Colorimetric and histochemical findings indicate that alkaline phosphatase is inhibited by shikonin, hempa, tepa and shikonin angelate. Cholinesterase is inhibited by all the compounds while diphenol oxidase is not inhibited. These findings have been discussed in the light of the earlier observations.