Advanced anaerobic digestion of municipal sludge using a novel and energy-efficient radio frequency pretreatment system

Microwave (MW) sludge pretreatment systems are usually limited to a frequency of 2.45 GHz and the heating frequency is constrained by commercially available hardware. Studies using MW heating at this frequency have reported negative net energy balance (output energy as methane minus input electrical energy). This necessitates further research into more efficient thermal pretreatment technologies. In this research, a novel and highly efficient radio frequency (RF) pretreatment system at a frequency of 13.56 MHz was designed, implemented, and tested for the first time. The system was custom-designed based on the dielectric characteristics of thickened waste activated sludge (TWAS) to achieve a very efficient and uniform heating system. The effects of three factors including pretreatment method (RF vs. MW), final temperature (60, 90 and 120 °C), and stationary (holding) time (0, 1 and 2 h) on sludge solubilization and performance of mesophilic batch anaerobic digestion were evaluated simultaneously. Energy measurements were also made to compare the efficiency of the custom-designed RF and conventional MW heating systems. The differences in sludge disintegration (solubilization) using the RF and MW pretreatment systems were negligible (P > 0.05). No statistically significant difference was also observed between the two pretreatment systems in terms of mesophilic biogas production rate and extent (P > 0.05). The energy efficiency of the RF pretreatment system was measured between 67.3 and 95.5% for the temperature range of 25-120 °C which was significantly higher than that of the MW system efficiency which varied from 37 to 43%. Overall, the average input energy of the RF system was less than half of the energy consumed during the operation of the MW system to achieve a same target temperature. Considering the results of this research, the RF heating at a frequency of 13.56 MHz is suggested as an effective and energy-efficient technique for thermal hydrolysis of TWAS.

Effects of functional endoscopic sinus surgery on the acoustics of the sinonasal tract

BACKGROUND

Nasal and paranasal cavities are supposed to contribute substantially to the vocal tract resonator properties. However, their acoustical effects as well as the effects of sinus surgery on the voice remain unclear. In this work we investigate resonance phenomena of paranasal sinuses prior to and after various rhinosurgical procedures in cadaveric human sinonasal tracts and corresponding 3D casts.

METHODOLOGY

Nasal and paranasal cavities of formalin-preserved cadavers and corresponding 3D replicas were excited by sine-tone sweeps from an earphone placed in the epipharynx. The response was picked up by a microphone at the nostrils. Different FESS procedures were performed and the acoustical responses following excitation were recorded. The measured acoustical changes in the obtained transfer functions were then evaluated.

RESULTS

Marked low frequency dips were detected in the transfer functions when sinus cavities were included in the nasal resonator system. These dips showed a significant correlation with sinus volumes. Following FESS procedures they moved upwards in frequency depending on the extent of the surgical intervention.

CONCLUSIONS

The transfer functions obtained in cadaveric situs and 3D replicas showed dips at the resonance frequencies of the paranasal cavities. Marked acoustic effects in terms of increase in dip frequency following FESS procedures were reproducibly documented.

Evaluation of the Safety of Drugs and Biological Products Used During Lactation: Workshop Summary

This report serves as a summary of a 2-day public workshop sponsored by the US Food and Drug Administration (FDA) to discuss the safety of drugs and biological products used during lactation. The aim of the workshop was to provide a forum to discuss the collection of data to inform the potential risks to breastfed infants with maternal use of medications during lactation. Discussions included the review of current approaches to collect data on medications used during lactation, and the considerations for future approaches to design and guide clinical lactation studies. This workshop is part of continuing efforts to raise the awareness of the public for women who choose to breastfeed their infants.

Bovine mammary gland X chromosome inactivation

X chromosome inactivation (XCI) is a process by which 1 of the 2 copies of the X chromosomes present in female mammals is inactivated. The transcriptional silencing of one X chromosome achieves dosage compensation between XX females and XY males and ensures equal expression of X-linked genes in both sexes. Although all mammals use this form of dosage compensation, the complex mechanisms that regulate XCI vary between species, tissues, and development. These mechanisms include not only varying levels of inactivation, but also the nature of inactivation, which can range from being random in nature to driven by parent of origin. To date, no data describing XCI in calves or adult cattle have been reported and we are reliant on data from mice to infer potential mechanisms and timings for this process. In the context of dairy cattle breeding and genomic prediction, the implications of X chromosome inheritance and XCI in the mammary gland are particularly important where a relatively small number of bulls pass their single X chromosome on to all of their daughters. We describe here the use of RNA-seq, whole genome sequencing and Illumina BovineHD BeadChip (Illumina, San Diego, CA) genotypes to assess XCI in lactating mammary glands of dairy cattle. At a population level, maternally and paternally inherited copies of the X chromosome are expressed equally in the lactating mammary gland consistent with random inactivation of the X chromosome. However, average expression of the paternal chromosome ranged from 10 to 90% depending on the individual animal. These results suggest that either the mammary gland arises from 1 or 2 stem cells, or a nongenetic mechanism that skews XCI exists. Although a considerable amount of future work is required to fully understand XCI in cattle, the data reported here represent an initial step in ensuring that X chromosome variation is captured and used in an appropriate manner for future genomic selection.

Detection and assessment of copy number variation using PacBio long-read and Illumina sequencing in New Zealand dairy cattle

Single nucleotide polymorphisms have been the DNA variant of choice for genomic prediction, largely because of the ease of single nucleotide polymorphism genotype collection. In contrast, structural variants (SV), which include copy number variants (CNV), translocations, insertions, and inversions, have eluded easy detection and characterization, particularly in nonhuman species. However, evidence increasingly shows that SV not only contribute a substantial proportion of genetic variation but also have significant influence on phenotypes. Here we present the discovery of CNV in a prominent New Zealand dairy bull using long-read PacBio (Pacific Biosciences, Menlo Park, CA) sequencing technology and the Sniffles SV discovery tool (version 0.0.1; https://github.com/fritzsedlazeck/Sniffles). The CNV identified from long reads were compared with CNV discovered in the same bull from Illumina sequencing using CNVnator (read depth-based tool; Illumina Inc., San Diego, CA) as a means of validation. Subsequently, further validation was undertaken using whole-genome Illumina sequencing of 556 cattle representing the wider New Zealand dairy cattle population. Very limited overlap was observed in CNV discovered from the 2 sequencing platforms, in part because of the differences in size of CNV detected. Only a few CNV were therefore able to be validated using this approach. However, the ability to use CNVnator to genotype the 557 cattle for copy number across all regions identified as putative CNV allowed a genome-wide assessment of transmission level of copy number based on pedigree. The more highly transmissible a putative CNV region was observed to be, the more likely the distribution of copy number was multimodal across the 557 sequenced animals. Furthermore, visual assessment of highly transmissible CNV regions provided evidence supporting the presence of CNV across the sequenced animals. This transmission-based approach was able to confirm a subset of CNV that segregates in the New Zealand dairy cattle population. Genome-wide identification and validation of CNV is an important step toward their inclusion in genomic selection strategies.

Ferrule-Effect Dominates Over Use of a Fiber Post When Restoring Endodontically Treated Incisors: An In Vitro Study

OBJECTIVES

 The aim of this study was to investigate the restoration of broken-down endodontically treated incisors with the ferrule effect using glass ceramic crowns bonded to composite resin core buildups with or without a fiber post. A no-ferrule group with post was also included for comparison.

METHODS AND MATERIALS

 Thirty decoronated endodontically treated bovine incisors with a 2-mm ferrule were restored with a direct buildup using a nanohybrid direct composite resin (Miris 2 and Optibond FL) with or without a glass-fiber-reinforced post. An additional group of 15 teeth without a ferrule were restored with buildup and a fiber post. All teeth were prepared to receive bonded glass ceramic crowns (e.max CAD luted with Variolink Esthetic DC) and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the incisal edge at an angle of 30° and a frequency of 5 Hz, beginning with a load of 100 N (×5000 cycles). A 100 N load increase was applied each 15,000 cycles. Specimens were loaded until failure or to a maximum of 1000 N (×140,000 cycles). Groups were compared using the Kaplan Meier survival analysis (log rank test at p=0.05).

RESULTS

 None of the tested specimens withstood all 140,000 load cycles. Specimens with posts but without a ferrule were affected by an initial failure phenomenon (wide gap at the lingual margin between the buildup/crown assembly and the root). There was a significant difference in mean survived cycles between the ferrule groups (Fp=73,332× and FNp=73,244×) and the no-ferrule group (50,121×; p=0.001). The addition of a fiber post was not significant in the presence of the ferrule (p=0.884). In both groups with posts, 100% of failures were unrestorable. The no-post group had 47% of restorable and possibly restorable failures.

CONCLUSIONS

 The survival of broken-down nonvital incisors was improved by the presence of the ferrule but not by the fiber-reinforced post. Fiber posts were always detrimental to the failure mode and were not able to compensate for the absence of a ferrule.

Patterns of service utilisation within Australian hepatology clinics: high prevalence of advanced liver disease

BACKGROUND

Liver diseases in Australia are estimated to affect 6 million people with a societal cost of $51 billion annually. Information about utilisation of specialist hepatology care is critical in informing policy makers about the requirements for delivery of hepatology-related healthcare.

AIMS

This study examined the aetiology and severity of liver disease seen in a tertiary hospital hepatology clinic, as well as the resource utilisation patterns.

METHODS

A longitudinal cohort study included consecutive patients booked in hepatology outpatient clinics during a 3-month period. Subsequent outpatient appointments for these patients over the following 12 months were then recorded.

RESULTS

During the initial 3-month period, 1471 appointments were scheduled with a hepatologist, 1136 of which were attended. Twenty-one per cent of patients were 'new cases'. Hepatitis B virus (HBV) was the most common disease aetiology for new cases (37%). Advanced disease at presentation varied between aetiology; only 5% of HBV cases had advanced liver disease at presentation, in contrast with HCV, NAFLD and ALD, in which advanced disease was identified at presentation in 31%, 46% and 72% of cases, respectively. Most patients (83%) attended multiple hepatology appointments, and a range of referral patterns for procedures, investigations and other specialty assessments were observed.

CONCLUSIONS

There is a high prevalence of HBV in new case referrals. Patients with HCV infection, NAFLD and ALD have a high prevalence of advanced liver disease at referral, requiring ongoing surveillance for development of decompensated liver disease and liver cancer. These findings that describe the patterns of health service utilisation among patients with liver disease provide useful information for planning sustainable health service provision for this clinical population.