Low-dissolved-oxygen nitrification in tropical sewage: an investigation on potential, performance and functional microbial community.

Intensive aeration for nitrification is a major energy consumer in sewage treatment plants (STPs). Low-dissolved-oxygen (low-DO) nitrification has the potential to lower the aeration demand. However, the applicability of low-DO nitrification in the tropical climate is not well-understood. In this study, the potential of low-DO nitrification in tropical setting was first examined using batch kinetic experiments. Subsequently, the performance of low-DO nitrification was investigated in a laboratory-scale sequential batch reactor (SBR) for 42 days using real tropical sewage. The batch kinetic experiments showed that the seed sludge has a relatively high oxygen affinity. Thus, the rate of nitrification was not significantly reduced at low DO concentrations (0.5 mg/L). During the operation of the low-DO nitrification SBR, 90% of NH4-N was removed. The active low-DO nitrification was mainly attributed to the limited biodegradable organics in the sewage. Fluorescence in-situ hybridisation and 16S rRNA amplicon sequencing revealed the nitrifiers were related to Nitrospira genus and Nitrosomonadaceae family. Phylogenetic analysis suggests 47% of the operational taxonomic units in Nitrospira genus are closely related to a comammox bacteria. This study has demonstrated active low-DO nitrification in tropical setting, which is a more sustainable process that could significantly reduce the energy footprint of STPs.

Haemorrhagic cerebral air embolism from an atrio-oesophageal fistula following atrial fibrillation ablation.

We report the case of a man found unconscious three weeks following atrial fibrillation (AF) ablation. Cranial and thoracic imaging demonstrated multiple areas of pneumo-embolic infarction secondary to an atrio-oesophageal fistula (AEF). AEF is a recognised, but rare, complication of AF ablation.(1-8) Early recognition is critical as the mortality is 100% without surgical intervention. We consider the postulated mechanisms of AEF formation, the spectrum of clinical presentation, investigations and treatment.

Magneto-optic spatial light modulator with submicron-size magnetic pixels for wide-viewing-angle holographic displays.

Spatial light modulators (SLMs) with submicron-size pixels are promising devices for use in wide-viewing-angle glasses-free holographic 3D displays. In accordance with estimations, an SLM with 1 µm pitch pixels can display holographic images over viewing angles of 30 deg. In the present work, we have studied magneto-optic SLMs (MOSLMs) with submicron-size pixels for wide-viewing-angle holographic displays that are driven by thermomagnetic recording. Amorphous TbFe films were used as a magneto-optic material. The MOSLM with an 800 nm diameter pixels array displayed wide-viewing-angle holographic images. These results demonstrated that MOSLMs with submicron-size pixels have promise for glasses-free holographic 3D displays.

Understanding the future research needs in Postural Orthostatic Tachycardia Syndrome (POTS): Evidence mapping the POTS adult literature.

POTS is under diagnosed with an estimated prevalence of 0.2%. North American and Australian researchers, as well as patient groups have called for more research into POTS. However, there has been no comprehensive appraisal of the current POTS evidence base. AIM: To map the POTS evidence base. METHODS: Two reviewers systematically searched 12 databases until July 1st 2019 using the search term "Postural Tachycardia Syndrome" (n = 7280) and categorised the literature. Inclusion criteria included all adult published literature with no language restrictions. 779 papers are analysed and mapped. RESULTS: Seven themes were identified: symptomology and quality of life 16.8% (n = 132), biomedical topics 16.5% (n = 130), co-morbidities 10.3% (n = 81), non-pharmacological management 9.8% (n = 77), aetiologies 6.9% (n = 53), pharmacological management 6.7% (n = 53), and clinical management 6.6% (n = 52). There 45 subthemes. Quality appraisal of the research studies (n = 233) evaluated design, sample size, outcome measures, data analysis and research biases. 74.8% (n = 175) were observational designs and 25.2% (n = 59) were experimental designs (16 using a randomised controlled design, 11 of which had a sample size greater than 21). 47.4% (n = 111) of studies only measured duration of effect for <1 day. 11.5% (n = 27) of studies reported outcomes using an unvalidated subjective measurement tool. CONCLUSION: The volume of adult POTS literature is small and the validity and reliability of the research lacks rigour. The evidence map methodology provides POTS researchers with a benchmark for research thus far. This paper adds an in-depth research appraisal to the broad calls for action, highlighting the pressing need for multicentre, good quality research in POTS, to support guidelines and consensus development in the future.

Complete laparoscopic excision of a giant retroperitoneal paraganglioma.

Paragangliomas (or 'extra-adrenal phaeochromocytomas') are rare tumours arising from neural crest cells. They occur most commonly in the abdomen along the paraspinal sympathetic ganglion. The malignancy rate can be up to 35% and surgical resection is the recommended treatment. While laparoscopic excision of phaeochromocytomas is now well established, the overall number of cases of paragangliomas reported is much smaller owing to their rarity (even more so for giant paragangliomas of ≥8cm) and controversy remains over the completeness of excision. Furthermore, the risk of malignancy and recurrence rate are higher in paragangliomas, with incomplete excision giving rise to recurrent endocrinopathy and carcinomatosis. We report the case of a 26-year-old woman who underwent laparoscopic excision of an 8.2cm functioning paraganglioma. Complete resection of the tumour was achieved and the patient's symptoms resolved. Twelve months later, she remains well with no evidence of recurrence.

Posttransplant antidonor antibodies and graft rejection. Evaluation by two-color flow cytometry.

The posttransplant production of antibodies against cryopreserved donor cells was studied in 50 consecutive cadaveric kidney graft recipients and in 23 additional patients selected for acute rejection. Serum was obtained twice weekly during the first 3 weeks posttransplant and then monthly for 6 months. IgM and IgG anti-T cell Abs were measured by 2-color flow cytometry. Results were analyzed in conjunction with the patients' demographics, previous sensitization, HLA-matching, posttransplant blood transfusions, incidence of delayed function, rejection episodes, and biopsy results. Antidonor antibodies, predominantly IgG, were detected in 19/48 (40%) of the patients proximate to the time of rejection. In contrast, antibodies were seen in only 2/22 (9%) of nonrejecting patients, and these antibodies were exclusively IgM. Younger patients were more likely to have antibody-mediated rejections. Cytotoxic antibody reactivity against panel cells developed or increased posttransplant in some patients, but it did not correlate with rejection. Previous sensitization and posttransplant transfusions favored the development of posttransplant panel reactivity but not of antidonor antibodies. Most rejections, including those associated with antidonor antibodies, were reversed by antirejection therapy. We conclude that antidonor antibodies are involved in a significant proportion of rejection episodes and that the damage induced does not necessarily culminate with loss of the graft.

Surface expression of HLA-C antigen by human extravillous trophoblast.

In this paper definitive evidence that the classical class I product, HLA-C, is expressed on the surface of normal trophoblast cells is provided. HLA-C transcripts were sequenced from cDNA isolated from first trimester trophoblast cells obtained by flow cytometric sorting. Both paternal and maternal alleles were transcribed. HLA-C proteins were demonstrated by biochemical analysis and found on the cell surface in association with beta(2)-microglobulin. Upregulation of cell surface HLA-C but not HLA-G expression after interferon (IFN)-gamma treatment was demonstrated by flow cytometric analysis. Immunohistology has confirmed HLA-C is expressed by all extravillous subpopulations in vivo. The question of whether trophoblast HLA-C molecules interact with decidual NK cells expressing killer Ig-like receptors (KIR) has also been addressed. Our results demonstrate that extravillous trophoblast expresses at least two HLA class I molecules, HLA-G and HLA-C on the cell surface.

Automated analysis of atrial late gadolinium enhancement imaging that correlates with endocardial voltage and clinical outcomes: a 2-center study.

BACKGROUND: For late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) assessment of atrial scar to guide management and targeting of ablation in atrial fibrillation (AF), an objective, reproducible method of identifying atrial scar is required. OBJECTIVE: To describe an automated method for operator-independent quantification of LGE that correlates with colocated endocardial voltage and clinical outcomes. METHODS: LGE CMR imaging was performed at 2 centers, before and 3 months after pulmonary vein isolation for paroxysmal AF (n = 50). A left atrial (LA) surface scar map was constructed by using automated software, expressing intensity as multiples of standard deviation (SD) above blood pool mean. Twenty-one patients underwent endocardial voltage mapping at the time of pulmonary vein isolation (11 were redo procedures). Scar maps and voltage maps were spatially registered to the same magnetic resonance angiography (MRA) segmentation. RESULTS: The LGE levels of 3, 4, and 5SDs above blood pool mean were associated with progressively lower bipolar voltages compared to the preceding enhancement level (0.85 ± 0.33, 0.50 ± 0.22, and 0.38 ± 0.28 mV; P = .002, P < .001, and P = .048, respectively). The proportion of atrial surface area classified as scar (ie, >3 SD above blood pool mean) on preablation scans was greater in patients with postablation AF recurrence than those without recurrence (6.6% ± 6.7% vs 3.5% ± 3.0%, P = .032). The LA volume >102 mL was associated with a significantly greater proportion of LA scar (6.4% ± 5.9% vs 3.4% ± 2.2%; P = .007). CONCLUSIONS: LA scar quantified automatically by a simple objective method correlates with colocated endocardial voltage. Greater preablation scar is associated with LA dilatation and AF recurrence.

Resonant behavior and selective switching of stop bands in three-dimensional photonic crystals with inhomogeneous components.

We demonstrate that, in contrast with the well-studied photonic crystals consisting of two homogeneous components, photonic crystals comprised of inhomogeneous or multiple (three or more) components may bring new opportunities to photonics due to the discovered quasiperiodic resonant behavior of their (hkl) stop bands as a function of the reciprocal lattice vector. A resonant stop band cannot be switched off for any permittivity of structural components. Tuning the permittivity or structural parameters allows the selective on-off switching of nonresonant (hkl) stop bands. This independent manipulation of light at different Bragg wavelengths provides a new degree of freedom to design selective optical switches and waveguides. Transmission experiments performed on synthetic opals confirmed the theoretical predictions.

An approach to haemorrhoids.

OBJECTIVE: Many patients with haemorrhoids are investigated because of the fear of missing colorectal cancer (CRC). The aim of this study was to determine whether a primarily clinical approach regarding the need for investigation was safe and did not miss patients with CRC. PATIENTS AND METHODS: Data was collected prospectively on 589 consecutive patients with the principle diagnosis of haemorrhoids at first clinic visit. All had clinical assessment including rigid sigmoidoscopy and were treated by phenol injection or banding. They were categorized for (1) no review unless symptoms persisted -'One Stop SOS' (2) outpatient review or (3) investigation. To check for the development of CRC they were contacted by postal questionnaire or telephone interview with a minimum of one year from diagnosis and treatment. All 589 patients were cross-referenced with the Pathology database and the Hospital Information Services System. RESULTS: Four hundred and sixty-nine (80%) answered the questionnaire; 352 patients (60% of the total group) fell in the 'one stop SOS' outpatient category; 95 (16%) patients were followed up to review response to treatment for large haemorrhoids; 105 (18%) were investigated with barium enema (12%), flexible sigmoidoscopy (4%), colonoscopy (1%) and miscellaneous (1%); 37 (6%) patients were either given a haemorrhoidectomy date or referred on with a different diagnosis. No patients selected for 'one-stop' treatment developed CRC. Five (0.8%) patients were diagnosed with CRC after appropriate investigation was instituted for suspicious symptoms. One patient with distal transverse colon cancer had a delayed diagnosis as she was investigated initially by flexible sigmoidoscopy. CONCLUSION: Most patients with the primary diagnosis of symptomatic haemorrhoids do not need investigation.