Mitigation of carbon steel biocorrosion using a green biocide enhanced by a nature-mimicking anti-biofilm peptide in a flow loop

Biocorrosion, also called microbiologically influenced corrosion (MIC), is a common operational threat to many industrial processes. It threatens carbon steel, stainless steel and many other metals. In the bioprocessing industry, reactor vessels in biomass processing and bioleaching are prone to MIC. MIC is caused by biofilms. The formation and morphology of biofilms can be impacted by fluid flow. Fluid velocity affects biocide distribution and MIC. Thus, assessing the efficacy of a biocide for the mitigation of MIC under flow condition is desired before a field trial. In this work, a benchtop closed flow loop bioreactor design was used to investigate the biocide mitigation of MIC of C1018 carbon steel at 25 °C for 7 days using enriched artificial seawater. An oilfield biofilm consortium was analyzed using metagenomics. The biofilm consortium was grown anaerobically in the flow loop which had a holding vessel for the culture medium and a chamber to hold C1018 carbon steel coupons. Peptide A (codename) was a chemically synthesized cyclic 14-mer (cys-ser-val-pro-tyr-asp-tyr-asn-trp-tyr-ser-asn-trp-cys) with its core 12-mer sequence originated from a biofilm dispersing protein secreted by a sea anemone which possesses a biofilm-free exterior. It was used as a biocide enhancer. The combination of 50 ppm (w/w) THPS (tetrakis hydroxymethyl phosphonium sulfate) biocide + 100 nM (180 ppb by mass) Peptide A resulted in extra 1-log reduction in the sulfate reducing bacteria (SRB) sessile cell count and the acid producing bacteria (APB) sessile cell count compared to 50 ppm THPS alone treatment. Furthermore, with the enhancement of 100 nM Peptide A, extra 44% reduction in weight loss and 36% abatement in corrosion pit depth were achieved compared to 50 ppm THPS alone treatment.

Pediatric Retinal Detachment in Homozygous Protein C Deficiency: Genetic and Phenotypic Description of a Single Family

Homozygous protein C deficiency is a rare hypercoagulability disorder. This study describes the ocular manifestations and the genetic background in a family with two affected children. This is a retrospective review of ophthalmic examinations, investigations, genetic testing, and blood work-up of two children with homozygous protein C deficiency from a single family. A family with a positive history of consanguineous marriage was found to have two affected children with homozygous protein C deficiency. Abnormal visual behavior was the presenting symptom. Both children had bilateral total tractional retinal detachments at presentation. Skin manifestations included episodes of discoloration and bruising. Laboratory work-up revealed absent protein C activity. Genetic testing confirmed the presence of a homozygous pathogenic mutation in protein C gene (NM_000312.3: c.1297G>A: p.Gly433Ser). Homozygous protein C deficiency should be considered in the differential diagnosis of early-onset tractional retinal detachment in infancy. Although rare, the ophthalmologist may be the first to encounter the condition, and treatment with protein C replacement or anticoagulants may be life-saving. Examination under anesthesia with fluorescein angiography and laser treatment early in life may be warranted to preserve vision. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:293-296.].

Adult-Onset Still's Disease After the ChAdOx1 nCoV-19 Vaccine

Adult-onset Still's disease (AOSD) is a rare autoimmune disorder without clear etiology. It is known that genetic and infectious causes trigger diseases. AOSD cases have been reported after coronavirus disease 2019 (COVID-19) infection and post influenza vaccine.

Here, we report this challenging case of adult-onset Still's disease in a patient who recently received the ChAdOx1 nCoV-19 vaccine (Oxford-AstraZeneca).

Effect of immunosuppressive therapy on oxygen saturation and diameter of retinal vessels in initial onset acute uveitis associated with Vogt-Koyanagi-Harada disease

PURPOSE

To demonstrate changes in oxygen saturation and calibre of retinal vessels in initial-onset acute uveitis associated with Vogt-Koyanagi-Harada (VKH) disease at baseline and during immunosuppressive therapy.

METHODS

In this prospective study, 22 patients (44 eyes) were studied. Retinal oximetry measurements were performed using the noninvasive spectrophotometric retinal oximeter (Oxymap T1) at baseline and at 1-3 months, 4-6 months, 5-7 months and more than 9 months after treatment.

RESULTS

At baseline, mean logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) was 1.12 ± 0.78 (Snellen equivalent, 20/265). Arteriolar and venular oxygen saturations were 108 ± 7% and 70 ± 9%, respectively and calibres of arterioles and venules were 12.1 ± 1.1 pixels and 16.9 ± 1.4 pixels, respectively. At 4-6 months of follow-up, logMAR BCVA was almost maximum (0.08 ± 0.1, Snellen equivalent 20/24; p < 0.001) and thereafter remained almost unchanged. After immunosuppressive therapy, arteriolar and venular oxygen saturation values continued to decrease up to >9 months of follow-up (92 ± 7% and 56 ± 10%, respectively; p < 0.001 for both arterioles and venules). Similarly, arteriolar and venular calibres continued to decrease up to >9 months of follow-up to 11.4 ± 0.9 pixels (p = 0.006) and 15.6 ± 1.3 pixels (p = 0.001), respectively.

CONCLUSIONS

Eyes with initial-onset acute uveitis associated with VKH disease have increased oxygen saturation and calibres of retinal vessels at baseline. Immunosuppressive therapy normalizes these changes and in a similar pattern improves BCVA.

Familial Retinal Arterial Macroaneurysms with Peripheral Retinal Ischemia: A Characterization on Ultra-Widefield Fluorescein Angiography

Retinal arterial macroaneurysm with supravalvular pulmonic stenosis (RAMSVPS), also known as familial retinal arterial macroaneurysm syndrome, is an autosomal recessive disorder associated with many life-threatening complications. The disease is characterized by progressive multiple retinal arterial macroaneurysms, retinal arterial beading, and recurrent vitreous hemorrhage. Here, we describe the first case of RAMSVPS associated with peripheral ischemia evident on ultra-widefield fluorescein angiography. A 23-year-old otherwise healthy woman presented to our ophthalmology emergency room with a 1-week history of right eye floaters and decreased vision. Dilated fundoscopic examination showed right eye vitreous and preretinal hemorrhage with bilateral active and involuted retinal arterial macroaneurysms, arterial beading, and sclerosed vessels. Ultra-widefield fluorescein angiography demonstrated multiple macroaneurysms on the optic discs and along the major retinal arteries in addition to significant peripheral retinal ischemia in both eyes. Echocardiography showed severe supravalvular pulmonic stenosis that required urgent pulmonary valvuloplasty. Indeed, peripheral retinal ischemia is an additional finding in RAMSVPS.

Phenotypic delineation of the retinal arterial macroaneurysms with supravalvular pulmonic stenosis syndrome

Retinal arterial macroaneurysms with supravalvular pulmonic stenosis (RAMSVPS), also known as Familial Retinal Arterial Macroaneurysms (FRAM) syndrome, is a very rare multisystem disorder. Here, we present a case series comprising ophthalmologic and systemic evaluation of patients homozygous for RAMSVPS syndrome causative IGFBP7 variant. New clinical details on 22 previously published and 8 previously unpublished patients are described. Age at first presentation ranged from 1 to 34 years. The classical feature of macroaneurysms and vascular beading involving the retinal arteries was universal. Follow up extending up to 14 years after initial diagnosis revealed recurrent episodes of bleeding and leakage from macroaneurysms in 55% and 59% of patients, respectively. The majority of patients who underwent echocardiography (18/23) showed evidence of heart involvement, most characteristically pulmonary (valvular or supravalvular) stenosis, often requiring surgical correction (12/18). Four patients died in the course of the study from complications of pulmonary stenosis, cerebral hemorrhage, and cardiac complications. Liver involvement (usually cirrhosis) was observed in eight patients. Cerebral vascular involvement was observed in one patient, and stroke was observed in two. We conclude that RAMSVPS is a recognizable syndrome characterized by a high burden of ocular and systemic morbidity, and risk of premature death. Recommendations are proposed for early detection and management of these complications.

Fate of benzotriazole and 5-methylbenzotriazole in recycled water recharged into an anaerobic aquifer: column studies

The fate of benzotriazole (BTri) and 5-methylbenzotriazole (5-MeBT) was investigated under anaerobic conditions at nano gram per litre concentrations in large-scale laboratory columns to mimic a managed aquifer recharge replenishment strategy in Western Australia. Investigations of BTri and 5-MeBT sorption behaviour demonstrated mobility of the compounds with retardation coefficients of 2.0 and 2.2, respectively. Degradation processes over a period of 220 days indicated first order biodegradation of the BTri and 5-MeBT under anaerobic aquifer conditions after a biological lag-time of approximately 30-60 days. Biodegradation half-lives of 29 ± 2 and 26 ± 1 days for BTri and 5-MeBT were respectively observed, with no threshold effect to biodegradation observed at the 200 ng L(-1). The detection of degradation products provided further evidence of BTri and 5-MeBT biodegradation. These results suggested that if BTri and 5-MeBT were present in recycled water recharged to the Leederville aquifer, biodegradation during aquifer passage is likely given sufficient aquifer residence times or travel distances between recycled water injection and groundwater extraction.

Benzotriazole and 5-methylbenzotriazole in recycled water, surface water and dishwashing detergents from Perth, Western Australia: analytical method development and application

A simplified and sensitive liquid chromatography mass spectrometry (LC-MS) method without requiring sample pre-concentration was successfully developed for detecting the occurrence of ultra-low (ng L(-1)) concentrations of benzotriazole (BTri), and its derivative 5-methyl benzotriazole (5-MeBT) in various Western Australian environmental water samples. The method detection limit was 2 ng L(-1), providing similar detection limits to other more process intensive methods where pre-concentration using solid phase extraction (SPE) was employed. The method was used to assess the occurrence of BTri and 5-MeBT in wastewater and surface water samples. Over a period of 12 months, BTri and 5-MeBT concentrations in secondary treated wastewater were measured, with the highest BTri and 5-MeBT concentrations observed during winter months at 78 ng L(-1) and 21 ng L(-1), respectively. The method was also used to assess the removal efficiency of BTri and 5-MeBT through an advanced water recycling plant (AWRP). While BTri was more persistent than 5-MeBT, both compounds were removed from the AWRP to <10 ng L(-1) (BTri) and <2 ng L(-1) (5-MeBT), with reverse osmosis (RO) providing the most effective treatment process for their removal.