Antifungal susceptibility profile of Candida clinical isolates from 22 hospitals of São Paulo State, Brazil.

This study aimed to evaluate the frequency of cryptic Candida species from candidemia cases in 22 public hospitals in São Paulo State, Brazil, and their antifungal susceptibility profiles. During 2017 and 2018, 144 isolates were molecularly identified as 14 species; C. parapsilosis (32.6%), C. albicans (27.7%), C. tropicalis (14.6%), C. glabrata (9.7%), C. krusei (2.8%), C. orthopsilosis (2.8%), C. haemulonii var. vulnera (2.1%), C. haemulonii (1.4%), C. metapsilosis (1.4%), C. dubliniensis (1.4%), C. guilliermondii (1.4%), C. duobushaemulonii (0.7%), C. kefyr (0.7%), and C. pelliculosa (0.7%). Poor susceptibility to fluconazole was identified in 6.4% of C. parapsilosis isolates (0.12 to >64 µg/mL), 50% of C. guilliermondii (64 µg/mL), 66.6% of C. haemulonii var. vulnera (16-32 µg/mL), and C. duobushaemulonii strain (MIC 64 µg/mL). Our results corroborated the emergence of C. glabrata in Brazilian cases of candidemia as previously reported. Importantly, we observed a large proportion of non-wild type C. glabrata isolates to voriconazole (28.6%; <0.015 to 4 µg/mL) all of which were also resistant to fluconazole (28.6%). Of note, C. haemulonii, a multidrug resistant species, has emerged in the Southeast region of Brazil. Our findings suggested a possible epidemiologic change in the region with an increase in fluconazole-resistant species causing candidemia. We stress the relevance of routine accurate identification to properly manage therapy and monitor epidemiologic trends.

Antifungal susceptibility profile of Candida clinical isolates from 22 hospitals of São Paulo State, Brazil

This study aimed to evaluate the frequency of cryptic Candida species from candidemia cases in 22 public hospitals in São Paulo State, Brazil, and their antifungal susceptibility profiles. During 2017 and 2018, 144 isolates were molecularly identified as 14 species; C. parapsilosis (32.6%), C. albicans (27.7%), C. tropicalis (14.6%), C. glabrata (9.7%), C. krusei (2.8%), C. orthopsilosis (2.8%), C. haemulonii var. vulnera (2.1%), C. haemulonii (1.4%), C. metapsilosis (1.4%), C. dubliniensis (1.4%), C. guilliermondii (1.4%), C. duobushaemulonii (0.7%), C. kefyr (0.7%), and C. pelliculosa (0.7%). Poor susceptibility to fluconazole was identified in 6.4% of C. parapsilosis isolates (0.12 to >64 µg/mL), 50% of C. guilliermondii (64 µg/mL), 66.6% of C. haemulonii var. vulnera (16-32 µg/mL), and C. duobushaemulonii strain (MIC 64 µg/mL). Our results corroborated the emergence of C. glabrata in Brazilian cases of candidemia as previously reported. Importantly, we observed a large proportion of non-wild type C. glabrata isolates to voriconazole (28.6%; <0.015 to 4 µg/mL) all of which were also resistant to fluconazole (28.6%). Of note, C. haemulonii, a multidrug resistant species, has emerged in the Southeast region of Brazil. Our findings suggested a possible epidemiologic change in the region with an increase in fluconazole-resistant species causing candidemia. We stress the relevance of routine accurate identification to properly manage therapy and monitor epidemiologic trends.

A landslide risk index for municipal land use planning in Portugal.

In Portugal landslides caused 237 fatalities and >1600 displaced people in the period 1865-2015. Spatial distribution and temporal patterns of slope instability can be related with a complex set of natural and human factors responsible for generating damages. It is essential to develop new methodologies to synthetize risk dimensions to contribute to the landslide risk management at the municipal level. This work proposed a municipal landslide risk index (LRI) considering three risk dimensions: hazard, exposure and physical vulnerability of buildings. The hazard dimension includes the landslide susceptibility performed at the national scale, the probability of weather types associated with landslides and an extreme precipitation susceptibility index. The exposure dimension considered the population density and the number of buildings, whereas the average physical vulnerability of the buildings was computed using four statistical variables from the official census: (i) construction technique and construction materials; (ii) reinforced structure; (iii) number of floors; and (iv) conservation status. Each variable includes different classes that were empirically weighted. After evaluating the three risk dimensions and the LRI, a cluster analysis was performed in order to identify the most important landslide risk drivers in each municipality. Exposure is the main driving force of LRI in the metropolitan areas of Lisbon and Porto, while the hazard is more relevant in the NW municipalities and the physical vulnerability is the major driving force in the south of the country. This methodological approach contributes to a comprehensive and synthetized knowledge about the landslide risk driving forces within the 278 Portuguese municipalities. In addition, it contributes to the diversification and context-oriented strategies of landslide risk management that still lacks in most of the national-level risk governance processes. Finally, this methodology can be generalized to other geographical contexts, improving the risk management, land use planning and the disaster risk reduction.

Defining evacuation travel times and safety areas in a debris flow hazard scenario.

Debris flows are one of the most hazardous types of landslides in mountain regions. In the upper part of the Zêzere valley (Serra da Estrela, Portugal) several debris flows events occurred in the last 200 years, some of them causing loss of lives and material damages. In this work, a methodology for pedestrian evacuation modelling, in a debris flow hazard scenario, was implemented. A dynamic run-out model, developed in previous studies, was used to evaluate the debris flows velocities, thickness of the deposits and extent of the mobilized material. The buildings potentially affected by the impact of debris flows were identified and the potentially exposed population was estimated by applying a dasymetric distribution. The results lead to the conclusion that, in the study area, the elderly are those who are most exposed to debris flows. Furthermore, the time lapse between the debris flows initiation and the arrival at the buildings at risk was estimated, allowing to account for the overall number of buildings where the evacuation time takes longer than the debris flows arrival. Additionally, the safe areas within the study area were identified, and several safe public buildings with the capacity to gather a large number of persons were selected. Considering that the study area is located in a mountain region, characterized by steep slopes, the evacuation modelling was performed based on an anisotropic approach, in order to consider the influence of slope direction on travel costs. At the end, three pedestrian evacuation travel time scenarios, based on different walking speeds to accommodate residents with different ages in safer places, were compared and the results mapped. The implemented methodology is not local dependent, which allows its reproduction elsewhere.

Dairy cows fed on tropical legume forages: effects on milk yield, nutrients use efficiency and profitability.

Two trials with multiparous dairy cows were conducted. Experiment 1 tested the effects of increasing forage proportion in the diet (500, 600, and 700 g/kg DM) when a mixed sorghum (Sorghum bicolor) and jackbean (Cannavalia ensiformis) silage was used as forage. Experiment 2 studied the substitution of sorghum silage and soybean meal by jackbean silage or fresh cowpea (Vigna unguiculata) forage in the diet. All diets were iso-energetic and iso-proteic. In each experiment, 30 cows were used and separated into three groups. In experiment 1, there were no differences in dry matter intake (DMI), milk yield (MY), or apparent total tract digestibility (aTTd) among the three diets, but milk fat content increased with increasing forage proportion, even though the similar neutral detergent fiber of all diets. Nitrogen use efficiency was highest in the diet containing 600 g forage/kg DM, and some evidence was observed for a better profitability with this forage proportion. In experiment 2, feeding legumes increased DMI despite no effects on aTTd. Milk yield increased in line with DMI, with a larger increase for the fresh cowpea. Nitrogen use efficiency and milk composition were not affected by the diets. The increased MY and lower feed costs increased the economic benefits when feeding legumes, particularly when feeding fresh cowpea. Feeding fresh cowpea or jackbean silage to dairy cows appears to be an alternative to soybean as protein source, ideally at a forage proportions of 600 g/kg DM, without altering milk yield and quality and increasing the farm profitability.

Metformin regulates global DNA methylation via mitochondrial one-carbon metabolism.

The anti-diabetic biguanide metformin may exert health-promoting effects via metabolic regulation of the epigenome. Here we show that metformin promotes global DNA methylation in non-cancerous, cancer-prone and metastatic cancer cells by decreasing S-adenosylhomocysteine (SAH), a strong feedback inhibitor of S-adenosylmethionine (SAM)-dependent DNA methyltransferases, while promoting the accumulation of SAM, the universal methyl donor for cellular methylation. Using metformin and a mitochondria/complex I (mCI)-targeted analog of metformin (norMitoMet) in experimental pairs of wild-type and AMP-activated protein kinase (AMPK)-, serine hydroxymethyltransferase 2 (SHMT2)- and mCI-null cells, we provide evidence that metformin increases the SAM:SAH ratio-related methylation capacity by targeting the coupling between serine mitochondrial one-carbon flux and CI activity. By increasing the contribution of one-carbon units to the SAM from folate stores while decreasing SAH in response to AMPK-sensed energetic crisis, metformin can operate as a metabolo-epigenetic regulator capable of reprogramming one of the key conduits linking cellular metabolism to the DNA methylation machinery.

Mapping landslide susceptibility using data-driven methods.

Most epistemic uncertainty within data-driven landslide susceptibility assessment results from errors in landslide inventories, difficulty in identifying and mapping landslide causes and decisions related with the modelling procedure. In this work we evaluate and discuss differences observed on landslide susceptibility maps resulting from: (i) the selection of the statistical method; (ii) the selection of the terrain mapping unit; and (iii) the selection of the feature type to represent landslides in the model (polygon versus point). The work is performed in a single study area (Silveira Basin - 18.2km2 - Lisbon Region, Portugal) using a unique database of geo-environmental landslide predisposing factors and an inventory of 82 shallow translational slides. The logistic regression, the discriminant analysis and two versions of the information value were used and we conclude that multivariate statistical methods perform better when computed over heterogeneous terrain units and should be selected to assess landslide susceptibility based on slope terrain units, geo-hydrological terrain units or census terrain units. However, evidence was found that the chosen terrain mapping unit can produce greater differences on final susceptibility results than those resulting from the chosen statistical method for modelling. The landslide susceptibility should be assessed over grid cell terrain units whenever the spatial accuracy of landslide inventory is good. In addition, a single point per landslide proved to be efficient to generate accurate landslide susceptibility maps, providing the landslides are of small size, thus minimizing the possible existence of heterogeneities of predisposing factors within the landslide boundary. Although during last years the ROC curves have been preferred to evaluate the susceptibility model's performance, evidence was found that the model with the highest AUC ROC is not necessarily the best landslide susceptibility model, namely when terrain mapping units are heterogeneous in size and reduced in number.

The effect of chicken blood and its components on wastewater characteristics and sewage surcharges.

Local wastewater treatment authorities levy surcharges from their non-residential customers that are based, in part, on the concentration of various pollutants in the customer's wastewater. Blood has long been recognized as the most potent contributor to pollutant loads in chicken processing plant wastewater. Quantification of the impact of blood on wastewater characteristics and sewage surcharges is hindered by lack of information on specific characteristics of chicken blood, and by the highly variable methods used by local authorities for calculating surcharges. In this study, the most commonly used wastewater characteristics are determined for whole chicken blood as well as its individual components. The characteristics measured include biochemical oxygen demand, chemical oxygen demand, total suspended solids, fats oil and grease, total Kjeldahl nitrogen, ammonia, and total phosphorus. Sewage surcharge calculation methods were collected from 71 local wastewater authorities. The results show all components of the blood to be extremely high-strength pollutants. The impact of blood on sewage surcharges is shown to be highly variable depending on the rates applied by the local authority.

3D surgical planning in patients affected by lipodystrophy.

Lipodystrophy is a pathological condition characterized by the focal or general absence of adipose tissue. Surgeons reset the patient's surface contours using injectable materials to recreate a normal physical appearance. However, due to difficulties in preoperative planning and intraoperative assessment, about 15% of the surgical procedures involved are reinterventions to improve volume or symmetry. This increases the need for an available, efficient tool capable of providing the surgeon with a good estimation of the volumes to be injected before the intervention proper begins. This work describes a virtual reality-based application for the surgical planning of facial lipodystrophy correction (FLIC). The tool uses points selected interactively by the surgeon to compute a curve that delimits the surface area to be operated on. It then automatically computes an estimated natural reconstructed surface and the quantity of volume that needs to be implanted during the intervention. Experiments have been carried out in which the filling volumes estimated using FLIC and ZBrush software were compared with the real volumes injected by the surgeon. ICCs higher than 0.97 indicate that there were no significant differences between the respective measurements, thus validating the tool proposed in this paper.

Flocculation of high purity wheat straw soda lignin.

In industrial process, acidification causes non-sulfonated lignin insolubility. The flocculants poly(diallyldimethylammonium chloride) (pDADMAC) and bovine blood (BB) also caused lignin insolubility while cationic polyacrylamide, chitosan, and soy protein PF 974 were ineffective. Turbidity determined optimal flocculant, but turbidity magnitude with BB was greater than expected. pDADMAC caused negative lignin Zeta potential to became positive, but BB-lignin Zeta potential was always negative. Insoluble lignin did not gravity sediment, and flocculant-lignin mixtures were centrifuged. Pellet and supernatant dry mass and corrected spectroscopic results were in good agreement for optimal pDADMAC and BB. Spectroscopy showed 87-92% loss of supernatant lignin. Nitrogen analysis showed BB concentrated in the pellet until the pellet became saturated with BB. Subtracting ash and BB mass from pellet and supernatant mass confirmed optimal BB. Low levels of alum caused increased lignin flocculation at lower levels of pDADMAC and BB, but alum did not affect optimal flocculant.

Triamcinolona intravítrea combinada con fotocoagulación láser en rejilla en pacientes con edema macular quístico y retinopatía diabética avanzada: estudio piloto / Intravitreal triamcinolone combined with grid laser photocoagulation for patients with cystoid macular edema and advanced diabetic retinopathy: pilot study

Objetivo: Determinar si el tratamiento inicial de inyección intravítrea de triamcinolona (TA) asociada a la fotocoagulación con láser en rejilla (FLR) es más efectivo que el tratamiento láser aislado en el edema macular diabético (EMD) quístico.MétodosEstudio clínico prospectivo no aleatorizado. Catorce ojos (14 pacientes) con diagnóstico de EMD quístico fueron tratados con FLR, según el protocolo del Estudio de Tratamiento Precoz de la Retinopatía Diabética (ETDRS), asociando una inyección de 4 mg de TA. Se seleccionó de forma retrospectiva un grupo control (16 ojos [16 pacientes]) tratado únicamente con FLR. Las principales medidas a analizar fueron los cambios en la agudeza visual (AV) y en el grosor del edema macular medido por tomografía de coherencia óptica (OCT).ResultadosEn el grupo tratado, la media de seguimiento fue de 14,9 meses (rango 12 a 19). La AV en tres ojos (21,4%) se incrementó > 2 líneas ETDRS, en cinco ojos (35,7%) permaneció sin cambios y en 6 ojos (42,8%) disminuyó > 2 líneas ETDRS. El grosor macular central disminuyó de media 106,2 μm (30,2%). No hubo diferencias estadísticamente significativas con el grupo control, en los cambios de la AV ni en la disminución del espesor macular (p = 0,2). En 4 ojos (28,5%) hubo incremento patológico de la presión intraocular.ConclusionesAunque todos nuestros pacientes mejoraron anatómicamente el EMD quístico en relación con los parámetros de OCT y angiografía fluoresceínica, el 42,8% perdieron dos o más líneas de AV con el tratamiento asociado de inyección intravítrea de TA y FLR. Añadir la inyección intravítrea de TA a la FLR no resultó efectiva a los 12 meses de seguimiento para el manejo del EMD quístico (AU)

Background: To determine if primary intravitreal injection of triamcinolone acetonide (TA)plus grid laser photocoagulation (GLP) is effective in treating cystoid diabetic macular edema(DME).Methods: Prospective comparative non-randomized clinical trial. Fourteen eyes (14 patients) diagnosed with cystoid DME were treated with GLP according to the Early Treatment Diabetic Retinopathy Study (ETDRS) guidelines, plus an intravitreal injection of 4 mg of TA. A matched control group (16 eyes [16 patients]) treated with GLP was selected retrospectively from ou rmedical records. Best-corrected visual acuity (BCVA), and quantitative change in optical coherence tomography (OCT) macular thickness were assessed. Results: Mean follow up was 14.9 months (12 to 19 months). In 3 (21.4%) eyes BCVA increased> 2 ETDRS lines, in 5 (35.7%) eyes BCVA remained the same, and BCVA decreased >2 ETDRS lines in 6 (42.8%) eyes. Central macular thickness, as measured by OCT, decreased a meanof 106.2 m (30.2%). The difference with the control group was not statistically significant (P=0.2). Four (28.5%) eyes developed an increased in intraocular pressure in our study group.Conclusions: Although all of our patients showed an improvement of cystoid DME by means of OCT and fluorescein angiography, 42.8% (6 eyes) lost 2 or more lines in BCVA with primary intravitreal injection of TA plus GLP. Primary intravitreal injection of TA plus GLP may not be effective for cystoid DME at 12-months (AU)

[Intravitreal triamcinolone combined with grid laser photocoagulation for patients with cystoid macular edema and advanced diabetic retinopathy: pilot study]. / Triamcinolona intravítrea combinada con fotocoagulación láser en rejilla en pacientes con edema macular quístico y retinopatía diabética avanzada: estudio piloto.

BACKGROUND: To determine if primary intravitreal injection of triamcinolone acetonide (TA) plus grid laser photocoagulation (GLP) is effective in treating cystoid diabetic macular edema (DME). METHODS: Prospective comparative non-randomized clinical trial. Fourteen eyes (14 patients) diagnosed with cystoid DME were treated with GLP according to the Early Treatment Diabetic Retinopathy Study (ETDRS) guidelines, plus an intravitreal injection of 4 mg of TA. A matched control group (16 eyes [16 patients]) treated with GLP was selected retrospectively from our medical records. Best-corrected visual acuity (BCVA), and quantitative change in optical coherence tomography (OCT) macular thickness were assessed. RESULTS: Mean follow up was 14.9 months (12 to 19 months). In 3 (21.4%) eyes BCVA increased > 2 ETDRS lines, in 5 (35.7%) eyes BCVA remained the same, and BCVA decreased >2 ETDRS lines in 6 (42.8%) eyes. Central macular thickness, as measured by OCT, decreased a mean of 106.2 µm (30.2%). The difference with the control group was not statistically significant (P = .2). Four (28.5%) eyes developed an increased in intraocular pressure in our study group. CONCLUSIONS: Although all of our patients showed an improvement of cystoid DME by means of OCT and fluorescein angiography, 42.8% (6 eyes) lost 2 or more lines in BCVA with primary intravitreal injection of TA plus GLP. Primary intravitreal injection of TA plus GLP may not be effective for cystoid DME at 12-months.

Effects of melatonin on DNA damage induced by cyclophosphamide in rats.

The antioxidant and free radical scavenger properties of melatonin have been well described in the literature. In this study, our objective was to determine the protective effect of the pineal gland hormone against the DNA damage induced by cyclophosphamide (CP), an anti-tumor agent that is widely applied in clinical practice. DNA damage was induced in rats by a single intraperitoneal injection of CP (20 or 50 mg/kg). Animals received melatonin during the dark period for 15 days (1 mg/kg in the drinking water). Rat bone marrow cells were used for the determination of chromosomal aberrations and of formamidopyrimidine DNA glycosylase enzyme (Fpg)-sensitive sites by the comet technique and of Xpf mRNA expression by qRT-PCR. The number (mean ± SE) of chromosomal aberrations in pinealectomized (PINX) animals treated with melatonin and CP (2.50 ± 0.50/100 cells) was lower than that obtained for PINX animals injected with CP (12 ± 1.8/100 cells), thus showing a reduction of 85.8% in the number of chromosomal aberrations. This melatonin-mediated protection was also observed when oxidative lesions were analyzed by the Fpg-sensitive assay, both 24 and 48 h after CP administration. The expression of Xpf mRNA, which is involved in the DNA nucleotide excision repair machinery, was up-regulated by melatonin. The results indicate that melatonin is able to protect bone marrow cells by completely blocking CP-induced chromosome aberrations. Therefore, melatonin administration could be an alternative and effective treatment during chemotherapy.

Effects of melatonin on DNA damage induced by cyclophosphamide in rats

The antioxidant and free radical scavenger properties of melatonin have been well described in the literature. In this study, our objective was to determine the protective effect of the pineal gland hormone against the DNA damage induced by cyclophosphamide (CP), an anti-tumor agent that is widely applied in clinical practice. DNA damage was induced in rats by a single intraperitoneal injection of CP (20 or 50 mg/kg). Animals received melatonin during the dark period for 15 days (1 mg/kg in the drinking water). Rat bone marrow cells were used for the determination of chromosomal aberrations and of formamidopyrimidine DNA glycosylase enzyme (Fpg)-sensitive sites by the comet technique and of Xpf mRNA expression by qRT-PCR. The number (mean ± SE) of chromosomal aberrations in pinealectomized (PINX) animals treated with melatonin and CP (2.50 ± 0.50/100 cells) was lower than that obtained for PINX animals injected with CP (12 ± 1.8/100 cells), thus showing a reduction of 85.8% in the number of chromosomal aberrations. This melatonin-mediated protection was also observed when oxidative lesions were analyzed by the Fpg-sensitive assay, both 24 and 48 h after CP administration. The expression of Xpf mRNA, which is involved in the DNA nucleotide excision repair machinery, was up-regulated by melatonin. The results indicate that melatonin is able to protect bone marrow cells by completely blocking CP-induced chromosome aberrations. Therefore, melatonin administration could be an alternative and effective treatment during chemotherapy.

Improved prediction of meat and bone meal metabolizable energy content for ducks through in vitro methods.

Apparent metabolizable energy (AME) of meat and bone meal (MBM) for poultry is highly variable, but impractical to measure routinely. Previous efforts at developing an in vitro method for predicting AME have had limited success. The present study uses data from a previous publication on the AME of 12 MBM samples, determined using 288 White Pekin ducks, as well as composition data on these samples. Here, we investigate the hypothesis that 2 noncompositional attributes of MBM, particle size and protease resistance, will have utility in improving predictions of AME based on in vitro measurements. Using the same MBM samples as the previous study, 2 measurements of particle size were recorded and protease resistance was determined using a modified pepsin digestibility assay. Analysis of the results using a stepwise construction of multiple linear regression models revealed that the measurements of particle size were useful in building models for AME, but the measure of protease resistance was not. Relatively simple (4-term) and complex (7-term) models for both AME and nitrogen-corrected AME were constructed, with R-squared values ranging from 0.959 to 0.996. The rather minor analytical effort required to conduct the measurements involved is discussed. Although the generality of the results are limited by the number of samples involved and the species used, they suggest that AME for poultry can be accurately predicted through simple and inexpensive in vitro methods.

Ensemble asteroseismology of solar-type stars with the NASA Kepler mission.

In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius, and age) and to test theories of stellar evolution. We find that the distribution of observed masses of these stars shows intriguing differences to predictions from models of synthetic stellar populations in the Galaxy.

Kepler detected gravity-mode period spacings in a red giant star.

Stellar interiors are inaccessible through direct observations. For this reason, helioseismologists made use of the Sun's acoustic oscillation modes to tune models of its structure. The quest to detect modes that probe the solar core has been ongoing for decades. We report the detection of mixed modes penetrating all the way to the core of an evolved star from 320 days of observations with the Kepler satellite. The period spacings of these mixed modes are directly dependent on the density gradient between the core region and the convective envelope.

Attenuation of TNF-driven murine ileitis by intestinal expression of the viral immunomodulator CrmD.

Tumor necrosis factor α (TNFα) is a key pathogenic factor in Crohn's disease and rheumatoid arthritis. TNF(ΔARE) mice express high levels of TNFα and present Crohn's-like ileitis and arthritis. Alterations in the chemokine network could underline the TNF-driven ileitis. The aim of this study was to evaluate the role of TNF and chemokines in ileitis using ectromelia virus cytokine response modifier D (CrmD), a protein that binds TNFα and a limited number of chemokines. We generated transgenic mice expressing CrmD in intestinal epithelial cells (vCrmD mice) and crossed them with the TNF(ΔARE) mice to test whether CrmD could affect TNF-driven inflammatory processes. During homeostasis, only the number of B cells in the lamina propria was reduced by CrmD expression. Interestingly, CrmD expression in the intestine markedly attenuated the inflammatory infiltrates in the ileum of TNF(ΔARE) mice, but did not affect development of arthritis. Our results suggest that CrmD affects development of ileitis by locally affecting both TNF and chemokine function in the ileum.

Proteins and peptides as renewable flocculants.

Partially hydrolyzed extracts from blood meal, feather meal, and meat and bone meal, as well as a variety of common surplus agricultural proteins were tested for their ability to promote the flocculation of clay. Partial alkaline or enzymatic hydrolyses of blood meal, feather meal, and meat and bone meal were performed to liberate proteins and peptides from their water-insoluble forms. Some of these extracts promoted flocculation. However, if hydrolysis was extensive, low molecular weight peptides were mainly produced, and these extracts did not promote flocculation. Beef skin gelatins and hydrolyzed fish collagen were found to promote flocculation when pH 5.5 buffer was added. Commercial preparations of peptone enzymatic digest and a mixture of keratin and hydrolyzed keratin did not promote flocculation.

Meat & bone meal extract and gelatin as renewable flocculants.

Readily available proteins were tested as renewable flocculants, and their actions were compared to that of anionic PAM, a common, commercial flocculant that requires the coaddition of a calcium ion source. Two soy proteins, a whey fraction, a porcine gelatin, and a meat & bone meal (MBM) extract were used in the flocculation test. It was found that MBM extract and porcine gelatin promoted clay flocculation, and flocculation was complete by 24h with or without the addition of calcium chloride. The other tested proteins did not promote clay flocculation, but all of the proteins were found to be adsorbed to clay. The protein adsorptions were well described by the Langmuir model, and gelatin and MBM extract had higher maximum adsorption capacities than the other proteins. Zwitterionic buffer solutions at pH 5.5, 7.0, and 10.0 were tested in the flocculation experiments. Addition of the pH 5.5 buffer caused the two soy proteins to become clay flocculants and lowered the concentration of gelatin and MBM extract necessary to promote complete flocculation by 24h. Calcium chloride was not required for flocculation. Under optimal testing conditions, the dried weight of gelatin or MBM extract was 2.6 and 17 times higher, respectively, than the weight of anionic PAM required for complete flocculation at 24h.