effective for urticaria. Medications that modulate neurologic function, including gabapentin, are effective for recalcitrant pruritus and less sedating than oral antihistamines.2 Treatment of comorbid depression or anxiety can also improve the symptoms and burden of pruritus.Patients without a dermatologic, neurologic, or psychiatric cause for pruritus should be asked about the presence of fevers, chills, night sweats, and/or unintended weight loss, as well as undergoing a full review of systems to assess for localizing symptoms. Physical examination would include palpation of the lymph nodes, spleen, and liver. Testing for a metabolic or neoplastic source of pruritus should be considered for patients with chronic, generalized pruritus who lack a primary skin disease.3 Systemic evaluation of these patients can include malignant neoplasm and thyroid, renal, hepatic, and infectious diseases. 4 Thus, it is important to remember the association of chronic pruritus and internal systemic diseases but to limit screening to the patients without recognizable skin disease. LESS IS MORE Competing Mortality in Cancer Screening A Teachable Moment Story From the Front LinesA 70-year-old man saw his primary care clinician and ex pressed concern about his lung cancer risk after learning a friend had recently died of it. The patient had had an 80-pack-year history, and had quit 7 years previously. His physician ordered a screening chest computed tomographic (CT) scan, which demonstrated a spiculated 12-mm lung nodule that was new when compared with scans done previously for other reasons. This prompted a positron emission tomographic scan, which showed metabolic activity, raising the suspicion for lung cancer. He was referred to a pulmonary-nodule clinic. The man presented to the pulmonary clinic in a wheel chair while receiving continuous oxygen. His medical history revealed severe diastolic heart failure; chronic obstructive pulmonary disease; obesity (his body mass index, calculated as weight in kilograms divided by height in meters squared, was 54); diabetes mellitus with microvascular complications, including stage III chronic kidney disease; and peripheral neuropathy. Additional medical history included several recent falls attributed to progressive neuropathy and deconditioning. These considerations were discussed with the patient and ultimately, invasive diagnostic testing was discouraged. A conservative plan that included a repeated CT scan in 4 months was mutually agreed on. Two months after this visit, the patient was admitted and treated for pneumonia. While recovering in the hospital, his primary team noted that this nodule had not undergone workup and he had another CT scan, which demonstrated interval growth. He was scheduled for an outpatient CT-guided biopsy.Prior to the biopsy, the patient was rehospitalized for pneumonia, this time requiring intensive care unit admission. His medical history was addressed at a multidisciplinary thoracic tumor conference. He was not a surgical candidate, and attempts to biopsy...
dCurrently, nitritation-anammox (anaerobic ammonium oxidation) bioreactors are designed to treat wastewaters with high ammonium concentrations at mesophilic temperatures (25 to 40°C). The implementation of this technology at ambient temperatures for nitrogen removal from municipal wastewater following carbon removal may lead to more-sustainable technology with energy and cost savings. However, the application of nitritation-anammox bioreactors at low temperatures (characteristic of municipal wastewaters except in tropical and subtropical regions) has not yet been explored. To this end, a laboratory-scale (5-liter) nitritation-anammox sequencing batch reactor was adapted to 12°C in 10 days and operated for more than 300 days to investigate the feasibility of nitrogen removal from synthetic pretreated municipal wastewater by the combination of aerobic ammonium-oxidizing bacteria (AOB) and anammox. The activities of both anammox and AOB were high enough to remove more than 90% of the supplied nitrogen. Multiple aspects, including the presence and activity of anammox, AOB, and aerobic nitrite oxidizers (NOB) and nitrous oxide (N 2 O) emission, were monitored to evaluate the stability of the bioreactor at 12°C. There was no nitrite accumulation throughout the operational period, indicating that anammox bacteria were active at 12°C and that AOB and anammox bacteria outcompeted NOB. Moreover, our results showed that sludge from wastewater treatment plants designed for treating high-ammonium-load wastewaters can be used as seeding sludge for wastewater treatment plants aimed at treating municipal wastewater that has a low temperature and low ammonium concentrations. N itrogen removal from wastewater treatment is necessary because of the significant adverse environmental impact of ammonia/ammonium, such as eutrophication and toxicity to aquatic life, on the receiving bodies. Generally, carbonaceous waste is removed in the first stage of wastewater treatment, which is followed by nitrogen removal systems. Conventionally, the removal of nitrogen (ammonium) is accomplished by the combination of nitrification and denitrification processes. Both of these are energy consuming and are associated with high costs. Moreover, these processes have an additional environmental impact due to high biomass production and greenhouse gas (CO 2 , N 2 O, etc.) emission, which promote global warming.Anaerobic ammonium-oxidizing (anammox) bacteria convert ammonium and nitrite directly to dinitrogen gas (N 2 ) under anoxic conditions. Since they were first detected in a denitrifying pilot plant by Mulder et al. in 1995 (1), anammox bacteria have been found in various oxygen-limited natural (2-4) and manmade ecosystems. The application of the anammox process in wastewater treatment results in significant energy reduction (60%) and greenhouse gas emission (90%) compared to those of traditional biological nitrogen removal processes (5-7). In fullscale nitritation-anammox wastewater treatment plants, ammonium-oxidizing bacteria (AOB) convert approx...
Autotrophic nitrogen removal in the mainstream wastewater treatment process is suggested to be a prerequisite of energy autarkic wastewater treatment plants (WWTP). Whilst the application of anammox-related technologies in the side-stream is at present state of the art, the feasibility of this energy-efficient process at mainstream conditions is still under development. Lower operating temperature and ammonium concentration, together with required high nitrogen removal efficiency, represent the main challenges to face in order to reach this appealing new frontier of the wastewater treatment field. In this study, we report the evaluation of the process in a plug-flow granular sludge-based pilot-scale reactor (4 m3) continuously fed with the actual effluent of the A-stage of the WWTP of Dokhaven, Rotterdam. The one-stage partial nitritation-anammox system was operated for more than 10 months at 19±1°C. Observed average N-removal and ammonium conversion rates were comparable or higher than those of conventional N-removal systems, with 182±46 and 315±33 mg-N L(-1) d(-1), respectively. Biochemical oxygen demand was also oxidized in the system with an average removal efficiency of 90%. Heterotrophic biomass grew preferentially in flocs and was efficiently washed out of the system. Throughout the experimentation, the main bottleneck was the nitritation process that resulted in nitrite-limiting conditions for the anammox conversion. Anammox bacteria were able to grow under mainstream WWTP conditions and new granules were formed and efficiently retained in the system.
Microbial biofilms can be both cause and cure to a range of emerging societal problems including antimicrobial tolerance, water sanitation, water scarcity and pollution. The identities of extracellular polymeric substances (EPS) responsible for the establishment and function of biofilms are poorly understood. The lack of information on the chemical and physical identities of EPS limits the potential to rationally engineer biofilm processes, and impedes progress within the water and wastewater sector towards a circular economy and resource recovery. Here, a multidisciplinary roadmap for addressing this EPS identity crisis is proposed. This involves improved EPS extraction and characterization methodologies, crossreferencing between model biofilms and full-scale biofilm systems, and functional description of isolated EPS with in situ techniques (e.g. microscopy) coupled with genomics, proteomics and glycomics. The current extraction and spectrophotometric characterization methods, often based on the principle not to compromise the integrity of the microbial cells, should be critically assessed, and more comprehensive methods for recovery and characterization of EPS need to be developed.
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