Determining the performance of lignin-based flocculants in improving biosludge dewaterability.

In the wastewater treatment plant of pulp and paper mills, biosludge dewatering is needed to reduce the sludge handling and disposal costs. It is usually facilitated by means of the addition of synthetic polymers. There is increasing interest in replacing synthetic polymers with biopolymers derived from low value by-products or industrial residuals to improve the environmental footprint of dewatering. In this study, lignin-based flocculants (LBF) were tested for their ability to improve the biosludge dewaterability based on Capillary Suction Time (CST) and dry cake solids achieved with a Crown Press. The results demonstrate that LBFs alone can significantly enhance dewatering with a decrease in CSTs from 72.7 ± 5.1 s (unconditioned biosludge) to 23.3 ± 0.4 s and an increase in dry cake solids after pressing from 7.1 ± 0.5% to 13.9 ± 1.3% with a relatively high dosage of 7.5% w/w. However, with dual conditioning a LBF and 0.1% w/w anionic polyacrylamide (APAM), the required dosage of LBF was reduced to 3% w/w to achieve a dry cake solids content of 13.8 ± 0.4%, the same as that achieved with Zetag8165, a commercial synthetic polymer. LBF addition lowered the particle surface charge, allowing the particles to agglomerate and enhancing for the biosludge dewaterability. The application of LBFs for sludge dewatering offers novel considerable promise for providing more sustainable approaches by optimizing the use of lignin from different extraction processes, applying various types of lignin modifications in combination with anionic polymers, and exploring different methods of disposal or utilization of the dewatered sludge.

Solid-State Anaerobic Digestion of Mixed Organic Waste: The Synergistic Effect of Food Waste Addition on the Destruction of Paper and Cardboard.

Full-scale anaerobic digestion processes for organic solid waste are common in Europe but are generally unaffordable in Canada and the United States because of inadequate regulations to restrict cheaper forms of disposal, particularly landfill. We investigated the viability of solid-state anaerobic digestion (SS-AD) as an alternative that reduces the costs of waste pretreatment and subsequent wastewater treatment. A laboratory SS-AD digester, comprising six 10 L leach beds and an upflow anaerobic sludge blanket reactor treating the leachate, was operated continuously for 88 weeks, with a mass balance based on chemical oxygen demand (COD) of 100 ± 2% (CODout/CODin). The feed was a mixture of fibers (cardboard, boxboard, newsprint, and fine paper) with varying amounts of food waste added. The process remained stable throughout. The addition of food waste caused a synergistic effect, raising methane production from the fiber mixture from a low of 52.7 L kg-1 COD fibersadded at no food waste, to 152 L kg-1 COD fibersadded at 29% food waste, an increase of 190%. Substrate COD destruction efficiency reached 65%, and the methane yield reached 225 L kg-1 CODadded at 29% food waste on a COD basis, with a solids retention time of 42 days. This performance was similar to that of a completely stirred tank reactor digesting similar wastes, but with much lower energy input. Multiple factors likely contributed to the enhanced fiber destruction, including the action of hydrolytic enzymes derived from fresh food waste and continuous leachate recirculation between leach beds of different ages.

Identification of a new epitope for HIV-neutralizing antibodies in the gp41 membrane proximal external region by an Env-tailored phage display library.

HIV controllers are a valuable source for the identification of HIV-neutralizing antibodies, as chronic infection over decades allows extensive affinity maturation of antibodies for improved Ag recognition. We analyzed a small cohort of elite controllers (ECs) for HIV-neutralizing antibodies using a panel of standardized HIV-1 pseudovirions on TZM-bl cells. An HIV-1 Env-tailored phage display library was generated to select epitopes targeted by neutralizing antibodies in the EC26 plasma sample showing the broadest neutralizing activity. Selected Env fragments were mostly allocated to the membrane proximal external region of gp41. After preabsorbing the EC26 plasma with the selected phage EC26-2A4, we achieved 50% depletion of its neutralizing activity. Furthermore, antibodies affinity-purified with the EC26-2A4 epitope from EC26 plasma showed neutralizing activity, proving that the selected phage indeed contains an epitope targeted by neutralizing plasma antibodies. Epitope fine mapping of the purified plasma antibodies on peptide arrays identified a new epitope overlapping, but clearly distinct, from the prominent 2F5 epitope. Of note, the purified antibodies did not show autoreactivity with cardiolipin, whereas low reactivity with phosphatidylserine comparable to mAb 2F5 was observed. Thus, this new epitope represents a promising candidate for further analysis in view of HIV vaccine development.

Using the Seraph® 100 Microbind® Affinity blood filter under slow flow conditions through 18 G and 16 G central lines.

INTRODUCTION: The Seraph® 100 Microbind® Affinity blood filter (Seraph® 100) has been in use since 2019 for the treatment of fulminant or difficult to treat blood stream infections as an adjunct to pharmacotherapy. In 2020 the device received emergency use authorization by the US Food and Drug Administration for the treatment of critically ill COVID-19 patients with confirmed or imminent respiratory failure. Results of an international registry showed that the Seraph® 100 was operated under blood flow rates of 100-350 mL/min. As those conditions require a large bore central line, a dialysis catheter is currently considered indispensable to operate the Seraph® 100. The use of smaller catheter lumina has neither been evaluated in vitro nor in vivo. METHODS: In vitro pressure data before and after the Seraph® 100 at various blood pump rates (prepump line 16 G, postpump line 18 G) with saline and human plasma were obtained. Further, anecdotal flow and pressure data of two patients treated with the Seraph® 100 for a COVID-19 infection are reported. RESULTS: At a pump speed of 50 mL/min pre-Seraph® pressure using saline was -70 [-70 to -60] mm Hg. In comparison, using plasma pre-Seraph® pressure was lower at -120 [-120 to -105] mm Hg; p < 0.001 (t-test). The post-Seraph® pressure at 50 mL/min using saline of 120 [110-130] mm Hg was not different from plasma at 130 [120-140] mm Hg, p = 0.152 (t-test). Blood flow rates of 50 mL/min did not lead to preAP levels below -250 mm Hg in the two clinical cases. CONCLUSION: Seraph® 100 blood flow rate of 50 mL/min may be achieved using low flow vascular access, allowing to treat a blood volume 72 L in 24 h.

Exploring the role of shelf sediments in the Arctic Ocean in determining the Arctic contamination potential of neutral organic contaminants.

The main objective of this study was to model the contribution of shelf sediments in the Arctic Ocean to the total mass of neutral organic contaminants accumulated in the Arctic environment using a standardized emission scenario for sets of hypothetical chemicals and realistic emission estimates (1930-2100) for polychlorinated biphenyl congener 153 (PCB-153). Shelf sediments in the Arctic Ocean are shown to be important reservoirs for neutral organic chemicals across a wide range of partitioning properties, increasing the total mass in the surface compartments of the Arctic environment by up to 3.5-fold compared to simulations excluding this compartment. The relative change in total mass for hydrophobic organic chemicals with log air-water partition coefficients ≥0 was greater than for chemicals with properties similar to typical POPs. The long-term simulation of PCB-153 generated modeled concentrations in shelf sediments in reasonable agreement with available monitoring data and illustrate that the relative importance of shelf sediments in the Arctic Ocean for influencing surface ocean concentrations (and therefore exposure via the pelagic food web) is most pronounced once primary emissions are exhausted and secondary sources dominate. Additional monitoring and modeling work to better characterize the role of shelf sediments for contaminant fate is recommended.

Identification of immunogenic proteins and generation of antibodies against Salmonella Typhimurium using phage display.

BACKGROUND: Solely in Europoe, Salmonella Typhimurium causes more than 100,000 infections per year. Improved detection of livestock colonised with S. Typhimurium is necessary to prevent foodborne diseases. Currently, commercially available ELISA assays are based on a mixture of O-antigens (LPS) or total cell lysate of Salmonella and are hampered by cross-reaction. The identification of novel immunogenic proteins would be useful to develop ELISA based diagnostic assays with a higher specificity. RESULTS: A phage display library of the entire Salmonella Typhimurium genome was constructed and 47 immunogenic oligopeptides were identified using a pool of convalescent sera from pigs infected with Salmonella Typhimurium. The corresponding complete genes of seven of the identified oligopeptids were cloned. Five of them were produced in E. coli. The immunogenic character of these antigens was validated with sera from pigs infeced with S. Tyhimurium and control sera from non-infected animals. Finally, human antibody fragments (scFv) against these five antigens were selected using antibody phage display and characterised. CONCLUSION: In this work, we identified novel immunogenic proteins of Salmonella Typhimurium and generated antibody fragments against these antigens completely based on phage display. Five immunogenic proteins were validated using a panel of positive and negative sera for prospective applications in diagnostics of Salmonela Typhimurium.

Deposition of brominated flame retardants to the Devon Ice Cap, Nunavut, Canada.

Brominated flame retardants (BFRs) can be transported to Arctic regions via atmospheric long-range transport, however, relatively little is known about their deposition to terrestrial environments. Snow cores from the Devon Ice Cap in Nunavut, Canada served to determine the recent depositional trends of BFRs. Snow pits were dug in 2005, 2006, and 2008. Dating using annual snow accumulation data, ion chemistry, and density measurements established that the pits covered the period from approximately 1993 to spring 2008. Samples were extracted under clean room conditions, and analyzed using GC-negative ion MS for 26 tri- to decabromodiphenyl ethers (BDEs), as well as other BFRs, nonbrominated flame retardants, and industrial chemicals. Decabromodiphenyl ether (BDE-209) was the major congener present in all samples followed by nona-BDEs (BDE-207, BDE-206, and BDE-208), both accounting for 89% and 7% of total BDE, respectively. BDE-209 concentrations were in most cases significantly correlated (P < 0.05) to tri- to nona-BDE homologues, and the strength of the correlations increased with increasing degree of bromination. Prior to or after deposition BDE-209 may be subject to debromination to lighter congeners. Deposition fluxes of BDE-209 show no clear temporal trend and range between 90 and 2000 pg·cm(-2)·year(-1). Back trajectory origin in densely populated areas of northeastern North America is significantly correlated (P < 0.005) with the BDE-209 deposition flux. Several other high production volume and/or alternative BFRs such as hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-dibromophenoxy)ethane (BTBPE), pentabromo ethyl benzene (PBEBz), and pentabromobenzene (PBBz), as well as the industrial chemical 1,3,5-tribromobenzene (135-TBBz) were found consistently in the snow pits.

Methane production potential of pulp mill sludges: microbial community and substrate constraints.

Sludges from pulp and paper mills represent a major ecological and environmental cost, and anaerobic digestion represents a method of waste reduction and energy recovery for these mills. This study compared methane production potential and microbial communities across 11 primary- and biosludges from five pulp and paper mills using various mill processes. We measured methane production from sludges in anaerobic batch reactor experiments over 64 days. Sludges were incubated with and without added substrate to test for organic substrate limitation versus inhibition of methanogens. Initial microbial communities and changes to community composition were determined using Illumina MiSeq for metabarcoding of bacterial and archaeal 16S rRNA genes. Mean methane production potential varied greatly between sludges (0.002-79 mL CH4 g-1 TS). Among primary sludges, kraft mill sludge produced more methane than other mill types. For these other mills, biosludge produced more methane than primary sludge, which had evidence of methanogen inhibition. Microbial communities and diversity were influenced by the initial community composition, and high methane production was only seen in sludges with high diversity. A number of sludges innately produced substantial methane and may be targets for further modelling and larger scale testing of anaerobic digestion.

Evaluation of the ideal length of the Seldinger needle for internal jugular vein catheter placement.

Placement of central venous catheters (CVC) into the internal jugular vein represents a routine clinical intervention. The periprocedural complication rate ranges from 5 to 20% and can be reduced by ultrasound guidance, training of residents and other measures. We aimed to proof that the average Seldinger needle is too long, increasing the risk of periprocedural injury, best epitomized in the stellate ganglion injury/irritation. The first part of the study was an online market analysis to investigate the standard needle length currently offered as part of the CVC placement sets. The second part of the study involved 35 hospitalized patients (14 female; median age 74.5 years). In those the distance between the skin and the internal jugular vein as well as the diameter of the internal jugular vein was measured by ultrasound in both, supine position as well as 45° semi-sitting position. In the third part of the study 80 body donors (45 female; median age 83.0 years) preserved by the ethanol/formaldehyde method were studied. In those the distance and angle between the typical landmark for insertion of the Seldinger needle for internal jugular vein catheter placement to the stellate ganglion was measured. The median [interquartile range] Seldinger needle length was 7 [4.0-10.0] cm. In the examined patients the maximum distance between the skin and the internal jugular vein was 1.87 cm. The minimum distance was 0.46 cm and the median distance averaging supine and 45° position was 1.14 [0.94-1.31] cm. Regarding the body donors the median distance from the insertion point of the internal jugular vein to the stellate ganglion was longer in men 5.5 [4.95-6.35] cm than in women 5.2 [4.7-5.9] (p = 0.031 unpaired t-test). With 7 cm average length the Seldinger needle currently sold as part of CVC sets is long enough to physically reach the stellate ganglion, not to mention more proximal structures. A shorter needle length would be sufficient to reach the internal jugular vein even in obese patients and with a small insertion angle while minimizing the possibility to cause severe injury as structures like the pleura and the stellate ganglion could not be reached by shorter needles.

More Drug Monitoring and Less CT Scans of the Brain: Gabapentin Overdose in Two Peritoneal Dialysis Patients.

In parallel with the decline of renal excretory function, drug dosing of many drugs becomes more challenging. Finding the right dose is even more difficult if kidney replacement therapy is instituted. This is further aggravated by the fact that even for substances with a narrow therapeutic range, drug monitoring is only rarely offered, let alone advocated. This holds also true for gabapentin, an anticonvulsant drug that is increasingly prescribed for indications such as cancer-related pain, restless legs syndrome, migraine, or uremic pruritus. The drug is excreted unchanged in urine, so plasma clearance of gabapentin is directly proportional to creatinine clearance. Hence, renal impairment reduces gabapentin excretion and increases plasma gabapentin concentrations in a linear fashion. Therefore, the elimination half-life of gabapentin is between 5 and 9 h, in patients with normal renal function but increases to 132 h in patients on dialysis. Epidemiological data from the USRDS underline this problem. About 19% of the 140,899 adult USA patients enrolled in Medicare coverage received gabapentin in 2011. Its use was associated with an increased risk of altered mental status, fall, and fracture. We report 2 patients in which overdose of gabapentin occurred. In 1 patient, severe neurological symptoms prompted an extensive diagnostic work up, while the underlying cause of the clinical presentation was a supra-therapeutic drug level of gabapentin. Consequently, symptoms subsided with the discontinuation of the drug. Indication and drug dose of gabapentin in dialysis patients should be tightly controlled, and drug monitoring used to avoid unintended overdose.

Fate of perfluorinated carboxylates and sulfonates during snowmelt within an urban watershed.

The transport dynamics of perfluorinated carboxylic acids and sulfonates during snowmelt in the highly urbanized Highland Creek watershed in Toronto, Canada was investigated by analyzing river water, bulk snow, and groundwater, sampled in February and March 2010, by means of liquid chromatography-tandem mass spectrometry. Perfluorohexanoate, perfluorooctanoate, and perfluorooctane sulfonate were dominant in river water, with concentrations of 4.0-14 ng·L(-1), 2.2-7.9 ng·L(-1), and 2.1-6.5 ng·L(-1), respectively. Relatively high levels of perfluorohexanoate may be related to the recent partial replacement in various consumer products of perfluorooctyl substances with shorter-chained perfluorinated compounds (PFCs). Highest PFC concentrations were found within the more urbanized part of the drainage area, suggestive of residential, industrial, and/or traffic-related sources. The riverine flux of PFCs increased during the snowmelt period, but only approximately one-fifth of the increased flux can be attributed to PFCs present in the snowpack, mostly because concentration in snow are generally quite low compared to those in river water. The remainder of the increased flux must be due to the mobilization of PFCs by the high flow conditions prevalent during snowmelt. Run-off behavior was clearly dependent on perfluoroalkyl chain length: Dilution with relatively clean snowmelt water caused a drop in the river water concentrations of short-chain PFCs at high flow during early melting. This prevented an early concentration peak of those water-soluble PFCs within the stream, as could have been expected in response to their early release from a melting snowpack. Instead, concentrations of particle-associated long-chain PFCs in creek water peaked early in the melt, presumably because high flow mobilized contaminated particles from impervious surfaces in the more urbanized areas of the watershed. The ability to enter the subsurface and deeper groundwater aquifers increased with the PFCs' water solubility, that is, was inversely related to perfluoroalkyl chain length.

Laboratory studies on the fate of perfluoroalkyl carboxylates and sulfonates during snowmelt.

Perfluoroalkyl acids (PFAAs) are anthropogenic chemicals that occur in snow from both remote and source regions. Experiments were conducted to determine how PFAAs are released from a melting snowpack. Different PFAAs eluted from the snowpack at different times, those with short chains eluting early, those with long chains eluting late. The concentrations in the meltwater of PFAAs with medium chain lengths of 6 to 9 perfluorinated carbon atoms first increased and then decreased during the melt period. Such a peak elution had not been previously observed for any other chemicals. The specific snow surface area (SSA) influenced this elution type, with peak concentrations occurring earlier in a snowpack with lower SSA. Model simulations suggested that the snow surface decrease during the melt alone was insufficient to explain the observations. It was ruled out that the calcium concentration affected PFAA sorption to the snow surface in a similar way as sorption to sediments. Adsorption coefficients of PFAAs to the snow surface were estimated by fitting the measured and modeled elution profiles.

Mercury fate in ageing and melting snow: development and testing of a controlled laboratory system.

A snow cover can modify when, to what extent, and in what form atmospherically deposited mercury is released to the underlying surface media and/or back to the atmosphere. Investigations of mercury transport and transformation processes in snow packs are hampered by the difficulty in controlling experimental and melt conditions and due to the huge variability in the composition and physical structure of environmental snow packs. A method was developed that allows the detailed mechanistic investigation of mercury fate in snow that is made, aged and melted under controlled laboratory conditions. A number of control samples established that mercury in indoor air, scavenged during the snow making process, constitutes the dominant source of mercury in the artificial snow. No addition of mercury is required. The amount of mercury in fresh snow was quantitatively (102 and 106% in two experiments) recovered in the dissolved and particulate fractions of the melt water and the vessel head space, confirming a mass balance for mercury and the absence of unquantifiable mercury sources and sinks in the experimental system. In snow made from unmodified tap water, more than half of the mercury present in the snowpack was recovered from the bottom of the snow vessel after all of the snow had melted. Such late elution is indicative of mercury being mostly associated with particles that are filtered by, and retained in, the shrinking snowpack. Addition of salt to the snow-making water at an environmentally realistic pH notably shifted the distribution of mercury in the snowpack from the particulate to the dissolved phase, resulting in more than 60% of the mercury eluting in the dissolved phase of early melt water fractions.

Phage display for the generation of antibodies for proteome research, diagnostics and therapy.

Twenty years after its development, antibody phage display using filamentous bacteriophage represents the most successful in vitro antibody selection technology. Initially, its development was encouraged by the unique possibility of directly generating recombinant human antibodies for therapy. Today, antibody phage display has been developed as a robust technology offering great potential for automation. Generation of monospecific binders provides a valuable tool for proteome research, leading to highly enhanced throughput and reduced costs. This review presents the phage display technology, application areas of antibodies in research, diagnostics and therapy and the use of antibody phage display for these applications.

Predictive value of heart rate in treatment of major depression with ketamine in two controlled trials.

OBJECTIVE: Ketamine has been shown to be effective in treatment of episodes of major depressive disorder (MDD). This controlled study aimed to analyse the predictive and discriminative power of heart rate (HR) and heart rate variability (HRV) for ketamine treatment in MDD. METHODS: In 51 patients, HR and HRV were assessed at baseline before and during ketamine infusion and 24 hours post ketamine infusion. Montgomery-Åsberg Depression Rating Scale (MADRS) was used to assess changes of depressive symptoms. A 30% or 50% reduction of symptoms after 24 hours or within 7 days was defined as response. A linear mixed model was used for analysis. RESULTS: Ketamine infusion increased HR and HRV power during and after infusion. Responders to ketamine showed a higher HR during the whole course of investigation, including at baseline with medium effect sizes (Cohen's d = 0.47-0.67). Furthermore, HR and HRV power discriminated between responders and non-responders, while normalized low and high frequencies did not. CONCLUSION: The findings show a predictive value of HR and HRV power for ketamine treatment. This further underlines the importance of the autonomous nervous system (ANS) and its possible malfunctions in MDD. SIGNIFICANCE: The predictive power of HR and HRV markers should be studied in prospective studies. Neurophysiological markers could improve treatment for MDD via optimizing the choice of treatments.

Theoretical and experimental simulation of the fate of semifluorinated n-alkanes during snowmelt.

Semifluorinated n-alkanes (SFAs) are highly fluorinated anthropogenic chemicals that are released into the environment through their use in ski waxes. Nothing is known about their environmental partitioning in general and their fate during snowmelt in particular. Properties were estimated for a range of SFAs with different chain lengths and degrees of fluorination using the SPARC calculator and poly parameter linear free energy relationships (ppLFERs). The calculations resulted in very low water solubility and vapor pressures and, consequently, high log KOW and log KOA values. Artificially produced snow in a cold room was spiked with a range of SFAs and subsequently melted with infrared lamps. Melt water, particles, and air samples taken during melting were analyzed. Both calculations and experiments showed that SFAs used in ski waxes will bind to particles or snow grain surfaces during snowmelt and thus are predicted to end up on the soil surface in skiing areas.