Novel Extrapolymeric Substances Biocoating on Polyvinylidene Fluoride Membrane for Enhanced Attached Growth of Navicula incerta.

Cell adhesion is always the first step in biofilm development. With the emergence of attached cultivation systems, this study aims to promote a cost-effective approach for sustainable cultivation of microalgae, Navicula incerta, by pre-coating the main substrates, commercial polyvinylidene fluoride (PVDF) membranes with its own washed algal cells and self-produced soluble extracellular polymeric substances (EPS) for strengthened biofilm development. The effects of pH value (6 to 9), cell suspension volume (10 to 30 mL), and EPS volume (10 to 50 mL) were statistically optimized by means of response surface methodology toolkit. Model outputs revealed good agreement with cell adhesion data variation less than 1% at optimized pre-coating conditions (7.20 pH, 30 mL cell suspension volume, and 50 mL EPS volume). Throughout long-term biofilm cultivation, results demonstrated that EPS pre-coating substantially improved the attached microalgae density by as high as 271% than pristine PVDF due to rougher surface and the presence of sticky exopolymer particles. Nutrients absorbed via the available EPS coating from the bulk medium made the immobilized cells to release less polysaccharides on an average of 30% less than uncoated PVDF. This work suggests that adhesive polymer binders derived from organic sources can be effectively integrated into the development of high-performance novel materials as biocoating for immobilized microalgae cultivation.

Bio-coatings in permeated cultivation systems: Unprecedented impacts on microalgal monoculture growth and organic matter yield.

Bio-coating, a recent and promising approach in attached microalgal cultivation systems, has garnered attention due to its efficiency in enhancing immobilized algal growth, particularly in submerged cultivation systems. However, when the cells are cultured on thin solid microporous substrates that physically separate them from the nutrient medium, it remains unclear whether the applied bio-coatings still have a significant impact on algal growth or the subsequent rates of algal organic matter (AOM) release. Therefore, this current work investigated the role of bio-coatings on the microalgal monoculture growth of one freshwater species, Chlorella vulgaris ESP 31, and one marine species, Cylindrotheca fusiformis on a hydrophilic substrate, polyvinylidene fluoride membrane in a permeated cultivation system. Wide range of bio-coating sources were adapted, with the result demonstrating that bacteria-derived coating promoted algal growth by as high as 140% when compared with the control group for both species. Interestingly, two distinct adaptation mechanisms were observed between the species, with only C. fusiformis demonstrating a positive correlation between cell growth and AOM productivity, particularly in its extracellularly bound fractions. It is worth noting that despite this specific fraction exhibiting the lowest content among all; it displayed significant relevance in terms of AOM productivity. High extracellular protein-to-polysaccharide ratio (>5.7 fold) quantified on bacterial intracellular exudate-coated membranes indirectly revealed an underlying symbiotic microalgal-bacterial interaction. This is the first study showing how bio-coating influenced AOM yield without any physical interaction between microalgae and bacteria. It further confirms the practical benefits of bio-coating in attached cultivation systems.

A review on microalgal-bacterial co-culture: The multifaceted role of beneficial bacteria towards enhancement of microalgal metabolite production.

Mass microalgal-bacterial co-cultures have come to the fore of applied physiological research, in particularly for the optimization of high-value metabolite from microalgae. These co-cultures rely on the existence of a phycosphere which harbors unique cross-kingdom associations that are a prerequisite for the cooperative interactions. However, detailed mechanisms underpinning the beneficial bacterial effects onto microalgal growth and metabolic production are rather limited at the moment. Hence, the main purpose of this review is to shed light on how bacteria fuels microalgal metabolism or vice versa during mutualistic interactions, building upon the phycosphere which is a hotspot for chemical exchange. Nutrients exchange and signal transduction between two not only increase the algal productivity, but also facilitate in the degradation of bio-products and elevate the host defense ability. Main chemical mediators such as photosynthetic oxygen, N-acyl-homoserine lactone, siderophore and vitamin B12 were identified to elucidate beneficial cascading effects from the bacteria towards microalgal metabolites. In terms of applications, the enhancement of soluble microalgal metabolites is often associated with bacteria-mediated cell autolysis while bacterial bio-flocculants can aid in microalgal biomass harvesting. In addition, this review goes in depth into the discussion on enzyme-based communication via metabolic engineering such as gene modification, cellular metabolic pathway fine-tuning, over expression of target enzymes, and diversion of flux toward key metabolites. Furthermore, possible challenges and recommendations aimed at stimulating microalgal metabolite production are outlined. As more evidence emerges regarding the multifaceted role of beneficial bacteria, it will be crucial to incorporate these findings into the development of algal biotechnology.

Membrane surface roughness promotes rapid initial cell adhesion and long term microalgal biofilm stability.

In biofilm membrane photobioreactors development, conscientious works revolving around the effect of external environment factors on microalgal biofilm growth were assessed but more comparative research about the role of carrier surfaces properties such as surface roughness is necessary. Thus, commercial polyethersulfone (PES) membranes with two different molecular-weight-cut-offs (1 kDa and 30 kDa) were selected as the main representatives of surface roughness in a 20 days long-term biofilm cultivation experiment under dynamic flow condition for the biofilm evolvement of three benthic diatoms (Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta). Results depicted that rougher 30 kDa PES enable higher cell attachment degree for C. fusiformis (25.85 ± 2.75 × 109 cells m-2), followed by A. coffeaeformis (11.86 ± 2.76 × 109 cells m-2) and N. incerta (10.10 ± 0.65 × 109 cells m-2). Bounded extracellular polymeric substances (bEPS) gathered were relatively higher than soluble EPS (sEPS) while bEPS accumulated at least 10% higher on smooth 1 kDa PES than rough 30 kDa PES for the purpose of enhancing the biofilm disruption resistivity under liquid flow. Moreover, cell adhesion mechanism was proposed via computational fluid dynamics in parallel with EPS analysis. Copious amount of asperities and stagnant zones present on rough 30 kDa surfaces accelerated biofilm development and the consistency of the results have a great valence for interpretation of microalgal biofilm lifestyle on porous surfaces.

Implementing routine blood-borne virus testing for HCV, HBV and HIV at a London Emergency Department - uncovering the iceberg?

UK guidelines recommend routine HIV testing in high prevalence emergency departments (ED) and targeted testing for HBV and HCV. The 'Going Viral' campaign implemented opt-out blood-borne virus (BBV) testing in adults in a high prevalence ED, to assess seroprevalence, uptake, linkage to care (LTC) rates and staff time taken to achieve LTC. Diagnosis status (new/known/unknown), current engagement in care, and severity of disease was established. LTC was defined as patient informed plus ⩾1 clinic visit. A total of 6211/24 981 ED attendees were tested (uptake 25%); 257 (4.1%) were BBV positive (15 co-infected), 84 (33%) required LTC. 100/147 (68%) HCV positives were viraemic; 44 (30%) required LTC (13 new, 16 disengaged). 26/54 (48%) HBV required LTC (seven new, 11 disengaged). 16/71 (23%) HIV required LTC (10 new, five disengaged). 26/84 (31%) patients requiring LTC had advanced disease (CD4 1, Fibroscan F3/F4 or liver cancer), including five with AIDS-defining conditions and three hepatocellular carcinomas. There were five BBV-related deaths. BBV prevalence was high (4.1%); most were HCV (2.4%). HIV patients were more successfully and quickly LTC than HBV or HCV patients. ED testing was valuable as one-third of those requiring LTC (new, disengaged or unknown status patients) had advanced disease.

[The situation of social support and its relationship with antenatal depression among 1 075 Zhejiang primiparas in their third trimesters].

Objective: To investigate the situation of social support (SS), and explore its relationship with antenatal depression (AD) among Zhejiang primiparas in their third trimesters. Methods: From March to August 2016, a cross-sectional study was conducted and the questionnaire was used at the outpatient consulting room of one maternity hospital in Hangzhou. Inclusion criteria includes the primiparas over 18 years old, gestation from 30 to 36 weeks, been able to understand and complete the questionnaires independently, no family history and history of mental disorders and no use of psychotropic drugs, without serious illness and so on. Exclusion criteria was that the primiparas were unable to complete all the contents of the questionnaire and of poor compliance. 1 150 questionnaires were actually given out, and 1 075 questionnaires were valid, so the valid rate was 93.48%. AD was evaluated by the Edinburgh Postnatal Depression Scale (EPDS) and SS was evaluated by the Perceived Social Support Scale (PSSS). SS between the non-AD group and the AD group was compared. The correlation between SS and AD was analyzed. Binary logistic regression model was used to assess the relationship between SS and AD. The level of SS was divided by average scores, groups lower than the average score was defined as the low-score group, groups higher than the average score was defined as the high-score group. Results: The prevalence of AD (score≥9) was 27.3% (293/1 075) among Zhejiang primiparas in their third trimesters. The scores of family support, friend support and other support, and the total score of SS among the non-AD group were 24.80±2.83, 23.40±3.00, 21.91±3.54 and 70.11±7.92, respectively, which were higher than those in the AD group (22.71±3.88, 21.45±3.59, 19.95±3.97, 64.10±10.01), (t values were 8.43, 8.29, 7.83 and 9.25, respectively, P<0.001 for all). The scores of family support, friend support and other support, and the total score of SS were negatively correlated with AD (rs values were-0.26,-0.25,-0.22 and-0.28, respectively, P<0.001 for all). Compared with low-score group, the scores of family support, friend support and other support, and the total score of SS among the high-score group had a lower risk of antenata depression among primiparas in their third trimesters, OR(95%CI) values were 0.56 (0.41-0.77), 0.66(0.47-0.92), 0.57(0.41-0.79) and 0.36(0.27-0.48), respectively. Conclusion: The prevalence of AD among Zhejiang primiparas was relatively high, and AD was negatively associated with SS level. We suggest adding SS in community pregnancy health management service in the future.

[Relationship between multi-slice spiral CT angiography imaging features and in-hospital death of patients with aortic dissection].

Objective: To explore the imaging manifestations of multi-slice spiral CT angiography (CTA) and relationship with in-hospital death in patients with aortic dissection (AD). Methods: The clinical data of 429 patients with AD who underwent CTA in Zhongshan Hospital of Fudan University between January 2009 and January 2016 were retrospectively analyzed. AD patients were divided into 2 groups, including operation group who underwent surgery or interventional therapy (370 cases) and non-operation group who underwent medical conservative treatment(59 cases). The multi-slice spiral CTA imaging features of AD were analyzed, and multivariate logistic regression analysis was used to investigate the relationship between imaging manifestations and in-hospital death in AD patients. Results: There were 12 cases (3.24%) of in-hospital death in operation group, and 28 cases (47.46%) of in-hospital death in non-operation group(P<0.001). AD involved different vascular branches. Multi-slice spiral CTA can clearly show the dissection of true and false lumen, and intimal tear was detected in 363 (84.62%) cases, outer wall calcification was revealed in 63 (14.69%) cases, and thrombus formation was present in 227 (52.91%) cases. The multivariate logistic regression analysis showed that the number of branch vessels involved (OR=1.374, 95%CI 1.081-1.745, P=0.009) and tearing false lumen range(OR=2.059, 95%CI 1.252-3.385, P=0.004) were independent risk factors of in-hospital death in AD patients, and the number of branch vessels involved (OR=1.600, 95%CI 1.062-2.411, P=0.025) was independent risk factor of in-hospital death in the operation group, while the tearing false lumen range (OR=2.315, 95%CI 1.019-5.262, P=0.045) was independent risk factor of in-hospital death of non-operation group. Conclusions: Multi-slice spiral CTA can clearly show the entire AD, true and false lumen, intimal tear, wall calcification and thrombosis of AD patients. The number of branch vessels involved and tearing false lumen range are the independent risk factors of in-hospital death in AD patients.

[Value of bedside echocardiography in diagnosis and risk assessment of in-hospital death for patients with Stanford type A aortic dissection].

Objective: To investigate the value of bedside echocardiography in diagnosis and risk assessment of in-hospital death of patients with Stanford type A aortic dissection. Methods: The clinical data of 229 patients with Stanford type A aortic dissection diagnosed by CT angiography in Zhongshan Hospital affiliated to Fudan University between January 2009 and January 2016 were retrospectively analyzed. The patients were divided into survival group(191 cases)and non-survival group(38 cases)according to presence or absence of in-hospital death. The bedside echocardiography features were analyzed, and influence factors of in-hospital death were determined by multivariate logistic regression analysis. Results: (1) Compared with the survival group, the non-survival group had lower surgery rate (60.52%(23/38) vs. 85.34%(163/191), P<0.01). Age, gender and Debakey classification were similar between survival group and death group (all P>0.05). (2) The bedside echocardiography results showed that prevalence of aortic valve involvement(65.79%(25/38) vs.34.03%(65/191), P<0.01) and severe aortic regurgitation (44.74%(17/38) vs. 14.14%(27/191), P<0.01) were significantly higher in non-survival group than in survival group. The non-survival group had larger aortic root diameter than the survival group ((55.5±6.4)mm vs. (42.3±7.8)mm, P<0.01). There were no significant differences in pericardial effusion, expansion of aortic sinus, and left ventricular ejection fraction between survival group and non-survival group (all P>0.05). (3) The multivariate logistic regression analysis showed that aortic valve involvement(OR=3.275, 95%CI 1.290-8.313, P<0.05), aortic root diameter(OR=1.202, 95%CI 1.134-1.275, P<0.01), and surgery (OR=0.224, 95%CI 0.079-0.629, P<0.01) were independent risk factors for in-hospital death in patients with Stanford type A aortic dissection. Conclusions: Bedside echocardiography has significant diagnostic value for Stanford type A aortic dissection. Aortic valve involvement, enlargement of aortic root diameter and without surgery are independent risk factors for patients with Stanford type A aortic dissection.

Incorporating HIV/hepatitis B virus/hepatitis C virus combined testing into routine blood tests in nine UK Emergency Departments: the "Going Viral" campaign.

OBJECTIVES: Routine HIV screening is recommended in those UK hospitals and primary care settings where the HIV prevalence is > 0.2%. For hepatitis B virus (HBV) and hepatitis C virus (HCV), however, testing is targeted at at-risk groups. We investigated the prevalence of these blood-borne viruses (BBVs) during a routine testing pilot in UK Emergency Departments (EDs). METHODS: During the "Going Viral" campaign (13-19 October 2014), nine UK EDs in areas of high HIV prevalence offered routine tests for HIV, HBV and HCV to adults having blood taken as part of routine care. Patients who tested positive were linked to care. RESULTS: A total of 7807 patients had blood taken during their ED visit; of these, 2118 (27%) were tested for BBVs (range 9-65%). Seventy-one BBV tests were positive (3.4%) with 32 (45.1%) new diagnoses. There were 39 HCV infections (15 newly diagnosed), 17 HIV infections (six newly diagnosed), and 15 HBV infections (11 newly diagnosed). Those aged 25-54 years had the highest prevalence: 2.46% for HCV, 1.36% for HIV and 1.09% for HBV. Assuming the cost per diagnosis is £7, the cost per new case detected would be £988 for HCV, £1351 for HBV and £2478 for HIV. CONCLUSIONS: In the first study in the UK to report prospectively on BBV prevalence in the ED, we identified a high number of new viral hepatitis diagnoses, especially hepatitis C, in addition to the HIV diagnoses. Testing for HIV alone would have missed 54 viral hepatitis diagnoses (26 new), supporting further evaluation of routine BBV testing in UK EDs.

Astrovirus VA1/HMO-C: an increasingly recognized neurotropic pathogen in immunocompromised patients.

BACKGROUND: An 18-month-old boy developed encephalopathy, for which extensive investigation failed to identify an etiology, 6 weeks after stem cell transplant. To exclude a potential infectious cause, we performed high-throughput RNA sequencing on brain biopsy. METHODS: RNA-Seq was performed on an Illumina Miseq, generating 20 million paired-end reads. Nonhost data were checked for similarity to known organisms using BLASTx. The full viral genome was sequenced by primer walking. RESULTS: We identified an astrovirus, HAstV-VA1/HMO-C-UK1(a), which was highly divergent from human astrovirus (HAstV 1-8) genotypes, but closely related to VA1/HMO-C astroviruses, including one recovered from a case of fatal encephalitis in an immunosuppressed child. The virus was detected in stool and serum, with highest levels in brain and cerebrospinal fluid (CSF). Immunohistochemistry of the brain biopsy showed positive neuronal staining. A survey of 680 stool and 349 CSF samples identified a related virus in the stool of another immunosuppressed child. CONCLUSIONS: The discovery of HAstV-VA1/HMO-C-UK1(a) as the cause of encephalitis in this case provides further evidence that VA1/HMO-C viruses, unlike HAstV 1-8, are neuropathic, particularly in immunocompromised patients, and should be considered in the differential diagnosis of encephalopathy. With a turnaround from sample receipt to result of <1 week, we confirm that RNA-Seq presents a valuable diagnostic tool in unexplained encephalitis.

Immune deficiency: changing spectrum of pathogens.

Current UK national standards recommend routine bacteriology surveillance in severe antibody-deficient patients, but less guidance exists on virology screening and viral infections in these patients. In this retrospective audit, we assessed the proportion of positive virology or bacteriology respiratory and stool samples from patients with severe, partial or no immune deficiency during a 2-year period. Medical notes were reviewed to identify symptomatic viral infections and to describe the course of persistent viral infections. During the 2-year period, 31 of 78 (39·7%) severe immune-deficient patients tested had a positive virology result and 89 of 160 (55.6%) had a positive bacteriology result. The most commonly detected pathogens were rhinovirus (12 patients), norovirus (6), Haemophilus influenzae (24), Pseudomonas spp. (22) and Staphylococcus aureus (21). Ninety-seven per cent of positive viral detection samples were from patients who were symptomatic. Low serum immunoglobulin IgA levels were more prevalent in patients with a positive virology sample compared to the total cohort (P = 0·0078). Three patients had persistent norovirus infection with sequential positive isolates for 9, 30 and 16 months. Virology screening of symptomatic antibody-deficient patients may be useful as a guide to anti-microbial treatment. A proportion of these patients may experience persistent viral infections with significant morbidity.

High prevalence of hepatitis C (HCV) in the emergency department (ED) of a London hospital: should we be screening for HCV in ED attendees?

An unlinked anonymous study was conducted to estimate the prevalence of hepatitis C virus (HCV) infection in emergency department (ED) attendees at a London Hospital. Nine hundred and ninety-seven samples collected over a 12-day period were tested for HCV antibody (Ab) and reactive samples were further tested for HCV RNA. The HCV seroprevalence was 2·6% (26/997) with 1·2% (12/997) HCV RNA positive. A peak HCV RNA-positive prevalence of 4·8% (3/63) was found in males aged 35-44 years, this was compared to 0% (0/136) in males aged <35 years (P = 0·0614) and 1·4% (4/278) in males aged ⩾45 years (P = 0·2415). Assuming the cost for HCV Ab is £6 and HCV RNA is £40 per test, screening ED attendees aged 25-54 years would cost £360 per viraemic infection and identify 82% of those who were HCV RNA positive, yielding the most favourable cost/benefit ratio. HCV screening of ED attendees aged 25-54 years in this population could be an effective way of identifying patients and limit onward transmission.

Whole-genome enrichment and sequencing of Chlamydia trachomatis directly from clinical samples.

BACKGROUND: Chlamydia trachomatis is a pathogen of worldwide importance, causing more than 100 million cases of sexually transmitted infections annually. Whole-genome sequencing is a powerful high resolution tool that can be used to generate accurate data on bacterial population structure, phylogeography and mutations associated with antimicrobial resistance. The objective of this study was to perform whole-genome enrichment and sequencing of C. trachomatis directly from clinical samples. METHODS: C. trachomatis positive samples comprising seven vaginal swabs and three urine samples were sequenced without prior in vitro culture in addition to nine cultured C. trachomatis samples, representing different serovars. A custom capture RNA bait set, that captures all known diversity amongst C. trachomatis genomes, was used in a whole-genome enrichment step during library preparation to enrich for C. trachomatis DNA. All samples were sequenced on the MiSeq platform. RESULTS: Full length C. trachomatis genomes (>95-100% coverage of a reference genome) were successfully generated for eight of ten clinical samples and for all cultured samples. The proportion of reads mapping to C. trachomatis and the mean read depth across each genome were strongly linked to the number of bacterial copies within the original sample. Phylogenetic analysis confirmed the known population structure and the data showed potential for identification of minority variants and mutations associated with antimicrobial resistance. The sensitivity of the method was >10-fold higher than other reported methodologies. CONCLUSIONS: The combination of whole-genome enrichment and deep sequencing has proven to be a non-mutagenic approach, capturing all known variation found within C. trachomatis genomes. The method is a consistent and sensitive tool that enables rapid whole-genome sequencing of C. trachomatis directly from clinical samples and has the potential to be adapted to other pathogens with a similar clonal nature.

Diagnosing HIV infection in patients presenting with glandular fever-like illness in primary care: are we missing primary HIV infection?

OBJECTIVES: The aim of the study was to examine the prevalence of HIV infection in patients presenting in primary care with glandular fever (GF)-like illness. METHODS: Samples from primary care submitted for a GF screen between April 2009 and June 2010 were identified. Samples without an HIV request were anonymized and retrospectively tested using a 4th-generation HIV antigen/antibody screening test. Reactive samples were further confirmed by an HIV antibody only test, with or without a p24 antigen assay. Antibody avidity testing based on the Recent HIV Infection Testing Algorithm (RITA) was used to identify individuals with evidence of recent acquisition (within 4-5 months). RESULTS: Of 1046 GF screening requests, concomitant HIV requests were made in 119 patients. Excluding one known positive patient, 2.5% (three of 118) tested HIV positive. Forty-five (4.3%) had a subsequent HIV test through another consultation within 1 year; of these, 4.4% (two of 45) tested positive. Of the remaining 882 patients, 694 (78.7%) had samples available for unlinked anonymous HIV testing, of which six (0.9%) tested positive. The overall HIV prevalence was 1.3% (11 of 857), with 72.7% (eight of 11) of cases missed at initial primary care presentation. Four of the nine (44.4%) available positive samples had evidence of recent acquisition, with three (75.0%) missed at initial primary care presentation. CONCLUSION: Low levels of HIV testing in patients presenting in primary care with GF-like illness are resulting in a significant number of missed HIV and seroconversion diagnoses. Local policy should consider adopting an opt-out strategy to include HIV testing routinely within the GF-screening investigation panel.

Bio-coatings as immobilized microalgae cultivation enhancement: A review.

Bio-coatings serve as artificial scaffolds for immobilizing microalgae to facilitate cell concentration and harvesting. It has been used as an additional step to enhance the natural microalgal biofilm cultivation and to promote new opportunities in artificially-immobilize cultivation technology of microalgae. This technique is able to enhance biomass productivities, enable energy and cost saving, water volume reduction and ease of biomass harvesting since the cells are physically isolated from the liquid medium. However, scientific discoveries of bio-coatings for process intensification are still lacking and their working principles remained unclear. Therefore, this critical review aims to shed light on the advancement of cell encapsulation systems (hydrogel coating, artificial leaf, bio-catalytic latex coating, and cellular polymeric coating) over the years and aid in the selection of appropriate bio-coating techniques for various applications. Discussion on the different preparation routes of bio-coatings, as well as the exploration towards the potential of bio-based coating materials such as natural/synthetic polymers, latex binders, and algal organic matters are also included, with a focus on sustainable pursuits. This review also presents in-depth investigations into the environmental applications of bio-coatings in wastewater remediation, air purification, carbon bio-fixation, and bio-electricity. The field of bio-coating in microalgae immobilization gives rise to a new ecofriendly strategy with scalable cultivation footprint and a balanced environmental risk aligning with the United Nation's Sustainable Development Goals with potential towards the contribution of Zero Hunger, Clean Water and Sanitation, Affordable and Clean Energy, and Responsible Consumption and Production.

A microscale system for in situ investigation of immobilized microalgal cell resistance against liquid flow in the early inoculation stage.

In attached microalgae cultivation systems, cell detachment due to fluid hydrodynamic flow is not a subject matter that is commonly looked into. However, this phenomenon is of great relevance to optimizing the operating parameters of algae cultivation and feasible reactor design. Hence, this current work miniaturizes traditional benchtop assays into a microfluidic platform to study the cell detachment of green microalgae, Chlorella vulgaris, from porous substrates during its early cultivation stage under precisely controlled conditions. As revealed by time lapse microscopy, an increase in bulk flow velocity facilitated nutrient transport but also triggered cell detachment events. At a flow rate of 1000 µL min-1 of growth medium for 120 min, the algal cell coverage was up to 5% lower than those at 5 µL min-1 and 50 µL min-1. In static seeding, the evolution of attached cell resistance toward liquid flows was dependent on hydrodynamic zones. The center zone of the microchannel was shown to be a "comfortable zone" of the attached cells to sequester nutrients effectively at lower medium flow rates but there was a profile transition where outlet zones favored cell attachment the most at higher flow rates (1.13 times higher than the center zone for 1000 µL min-1). Besides, computational fluid dynamics (CFD) simulations illustrated that the focusing band varied between cross-sections and depths, while the streamline was the least concentrated along the side walls and bottom plane of the microfluidic devices. It was intriguing to learn that cell detachment was not primarily happening along the symmetry streamline. Insight gained from this study could be further applied in the optimization of operating conditions of attached cultivation systems whilst preserving laminar flow conditions.

Microalgal extract as bio-coating to enhance biofilm growth of marine microalgae on microporous membranes.

Microalgal biofilm is a popular platform for algal production, nutrient removal and carbon capture; however, it suffers from significant biofilm exfoliation under shear force exposure. Hence, a biologically-safe coating made up of algal extracellular polymeric substances (EPS) was utilized to secure the biofilm cell retention and cell loading on commercial microporous membrane (polyvinylidene fluoride), making the surfaces more hydrophobic (contact angle increase up to 12°). Results demonstrated that initial cell adhesion of three marine microalgae (Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta) was enhanced by at least 1.3 times higher than that of pristine control within only seven days with minimized biofilm exfoliation issue due to uniform distribution of sticky transparent exopolymer particles. Bounded extracellular polysaccharide gathered was approximately 23% higher on EPS-coated membranes to improve the biofilm's hydraulic resistance, whereas bounded extracellular protein would only be substantially elevated after the attached cells re-accommodate themselves onto the EPS pre-coating of themselves. In accounting the rises of hydrophobic protein content, biofilm was believed to be more stabilized, presumably via hydrophobic interactions. EPS biocoating would generate a groundswell of interest for bioprocess intensifications though there are lots of inherent technical and molecular challenges to be further investigated in future.

Uncovering the role of algal organic matter biocoating on Navicula incerta cell deposition and biofilm formation.

Spontaneous natural biofilm concentrates microalgal biomass on solid supports. However, the biofilm is frequently susceptible to exfoliation upon nutrient deficiency, particularly found in aged biofilm. Therefore, this study highlights a novel biofilm cultivation technique by pre-depositing the algal organic matters from marine diatom, Navicula incerta onto microporous polyvinylidene fluoride membrane to further strengthen the biofilm developed. Due to the improvement in membrane surface roughness and hydrophobicity, cells adhered most abundantly to soluble extrapolymeric substances-coated (sEPS) (76×106±16×106 cells m-2), followed by bounded EPS-coated (57.67×106±0.33×106 cells m-2), internally organic matter (IOM)-coated (39.00×106±5.19×106 cells m-2), and pristine control the least (6.22×106±0.77×106 cells m-2) at 24th h. Surprisingly, only bEPS-coated membrane demonstrated an increase in cell adhesion toward the end of the experiment at 72 h. The application of the bio-coating has successfully increased the rate of cell attachment by at least 45.3% upon inoculation and achieved as high as 89.9% faster attachment at 72 hours compared to the pristine control group. Soluble polysaccharides and proteins might be carried along by the cells adhering onto membranes hence resulting in a built up of EPS hydrophobicity (>70% in average on bio-coated membranes) over time as compared with pristine (control) that only recorded an average of approximately 50% hydrophobicity. Interestingly, cells grown on bio-coated membranes accumulated more internally bounded polysaccharides, though bio-coating had no discernible impact on the production of both externally and internally bounded protein. The collective findings of this study reveal the physiological alterations of microalgal biofilms cultured on bio-coated membranes.

Performance of the GeneXpert CT/NG assay compared to that of the Aptima AC2 assay for detection of rectal Chlamydia trachomatis and Neisseria gonorrhoeae by use of residual Aptima Samples.

There are currently no commercially available molecular assays for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in rectal swabs with regulatory approval. We compared the Cepheid GeneXpert CT/NG assay with the GenProbe Aptima Combo2 assay, using 409 rectal swabs. Using Aptima as the gold standard, the sensitivity, specificity, and positive and negative predictive values of GeneXpert for the detection of C. trachomatis and N. gonorrhoeae were 86%, 99.2%, 92.5%, and 98.4% and 91.1%, 100%, 100%, and 98.6%, respectively. Despite significant dilution of samples prior to GeneXpert testing, the assay performed well with excellent specificity.

ARHAI: antiviral resistance.

Development of antiviral resistance is a particular concern for the Advisory Committee on Antimicrobial Resistance and Healthcare-Associated Infections (ARHAI). Over the last 4 years, considerable time has been devoted to examining the ability of the UK to monitor the presence and transmission of antiviral resistance. Resistances to antiviral agents in influenza virus, HIV and hepatitis B and C viruses were identified as the main targets. The emphasis is on a network of laboratories that are able to perform diagnostic tests for resistance and to participate in surveillance programmes with co-ordination either through a central reference facility in the HPA or a collaborative study group.