Modeling Microplastic Transport in the Marine Environment: Testing Empirical Models of Particle Terminal Sinking Velocity for Irregularly Shaped Particles

Microplastic (mP) pollution has been indicated as an area of concern in the marine environment. However, there is no consensus on their potential to cause significant ecological harm, and a comprehensive risk assessment of mP pollution is unattainable due to gaps in our understanding of their transport, uptake, and exchange processes. This research considers drag models that have been proposed to calculate the terminal settling velocity of regularly and irregularly shaped particles to assess their applicability in a mP modeling context. The evaluation indicates three models that predict the settling velocity of mPs to a high precision and suggests that an explicit model is the most appropriate for implementation in a mP transport model. This research demonstrates that the mP settling velocity does not vary significantly over time and depth relevant to the scale of an ocean model and that the terminal settling velocity is independent of the initial particle velocity. These findings contribute toward efforts to simulate the vertical transport of mPs in the ocean, which will improve our understanding of the residence time of mPs in the water column and subsequently their availability for uptake into the marine ecosystem.

Detection of human adenovirus F41 in wastewater and its relationship to clinical cases of acute hepatitis of unknown aetiology

As of 8 July 2022, the World Health Organization (WHO) have reported 1010 probable cases of acute hepatitis of unknown aetiology in children worldwide, including approximately 250 cases in the United Kingdom (UK). Clinical presentations have often been severe, with liver transplantation a frequent clinical outcome. Human adenovirus F41 (HAdV-F41) has been detected in most children with acute hepatitis, but its role in the pathogenesis of this infection has yet to be established. Wastewater-based epidemiology (WBE) has become a well-established tool for monitoring the community spread of SARS-CoV-2, as well as other pathogens and chemicals. In this study, we adopted a WBE approach to monitoring levels of HAdV-F40/41 in wastewater before and during an acute hepatitis outbreak in Northern Ireland. We report increasing detection of HAdV-F40/41 in wastewater, concomitant with increasing numbers of clinical cases. Amplicon whole genome sequencing further classified the wastewater-derived HAdV as belonging to the F41 genotype which in turn was homologous to clinically derived sequences. We propose that WBE has the potential to inform community surveillance of HAdV-F41 and can further contribute to the ongoing global discussion supporting HAdV-F41 involvement in acute hepatitis cases.

Outcomes following excision of Morton's interdigital neuroma: a prospective study

AIMS

This is the first prospective study to report the pre- and post-operative patient reported outcomes and satisfaction scores following excision of interdigital Morton's neuroma.

PATIENTS AND METHODS

Between May 2006 and April 2013, we prospectively studied 99 consecutive patients (111 feet) who were to undergo excision of a Morton's neuroma. There were 78 women and 21 men with a mean age at the time of surgery of 56 years (22 to 78). Patients completed the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12 (SF-12) and a supplementary patient satisfaction survey three months pre-operatively and six months post-operatively.

RESULTS

Statistically significant differences were found between the mean pre- and post-operative MOXFQ and the physical component of the SF-12 scores (p = 0.00081 and p = 0.00092 respectively). Most patients reported their overall satisfaction as excellent (n = 49, 49.5%) or good (n = 29, 29.3%), but ten patients were dissatisfied, reporting poor (n = 8, 8.1%) or very poor (n = 2, 2.0%) results. Only 63 patients (63%) were pain-free at follow-up: in eight patients (8.1%), the MOXFQ score worsened. There was no statistically significant difference in outcome between surgery on single or multiple sites. However, the MOXFQ scores were significantly worse after revision surgery (p = 0.004).

CONCLUSIONS

The patient-reported outcomes after resection of a symptomatic Morton's neuroma are acceptable but may not be as good as earlier studies suggest. Surgery at several sites can be undertaken safely but caution should be exercised when considering revision surgery. Cite this article: Bone Joint J 2016;98-B:1376-81.

Metallic hemiarthroplasty for the treatment of end-stage hallux rigidus

Aims

To examine the mid-term outcome and cost utility of the BioPro metallic hemiarthroplasty for the treatment of hallux rigidius.

Patients and Methods

We reviewed 97 consecutive BioPro metallic hemiarthroplasties performed in 80 patients for end-stage hallux rigidus, with a minimum follow-up of five years. There were 19 men and 61 women; their mean age was 55 years (22 to 74). No patient was lost to follow-up.

Results

A total of 12 patients (15 first metatarso-phalangeal joints (MTPJs)) required a revision; one for infection, two for osteolysis and 12 for pain. The all cause rate of survival at five years was 85.6% (95% confidence interval (CI) 83.5 to 87.9). Younger age was a significant predictor of revision (odds ratio 1.09, 95% CI 1.02 to 1.17, p = 0.014) on excluding infection and adjusting for confounding variables (Cox regression). Significant improvements were demonstrated at five years in the Manchester Oxford Foot Questionnaire (13.9, 95% CI 10.5 to 17.2) and in the physical component of the Short Form-12 score (6.5, 95% CI 4.1 to 8.9). The overall rate of satisfaction was 75%. The cost per quality adjusted life year at five years, accounting for a 14% rate of revision was between £4431 and £6361 depending on the complexity and morbidity of the patient.

Conclusion

The BioPro hemiarthroplasty offers good short to mid-term functional outcome and is a cost effective intervention. The relatively high revision rate is associated with younger age and perhaps the use of this implant should be limited to older patients. Cite this article: Bone Joint J 2016;98-B:945–51.

A thermodynamically-based model for predicting microbial growth and community composition coupled to system geochemistry: Application to uranium bioreduction

'Bioimmobilization' of redox-sensitive heavy metals and radionuclides is being investigated as a way to remediate contaminated groundwater and sediments. In one approach, growth-limiting substrates are added to the subsurface to stimulate the activity of targeted groups of indigenous microorganisms and create conditions favorable for the microbially-mediated reductive precipitation ('bioreduction') of targeted contaminants. We present a theoretical framework for modeling this process that modifies conventional geochemical reaction path modeling to include thermodynamic descriptions for microbial growth and may be called biogeochemical reaction path modeling. In this approach, the actual microbial community is represented by a synthetic microbial community consisting of a collection of microbial groups; each with a unique growth equation that couples a specific pair of energy yielding redox reactions. The growth equations and their computed standard-state free energy yields are appended to the thermodynamic database used in conventional geochemical reaction path modeling, providing a direct coupling between chemical species participating in both microbial growth and geochemical reactions. To compute the biogeochemical reaction paths, growth substrates are reacted incrementally with the defined geochemical environment and the coupled equations are solved simultaneously to predict reaction paths that display changing microbial biomass, community composition (i.e. the fraction of total biomass in each microbial group), and the aqueous and mineral composition of the system, including aqueous speciation and oxidation state of the targeted contaminants. The approach, with growth equations derived from the literature using well-known bioenergetics principles, was used to predict the results of a laboratory microcosm experiment and an in situ field experiment that investigated the bioreduction of uranium. Predicted effects of ethanol or acetate addition on uranium concentration and speciation, major ion geochemistry, mineralogy, microbial biomass and community composition were in qualitative agreement with experimental observations although the available data precluded rigorous model testing. While originally developed for use in better understanding of bioimmobilization of heavy metals and radionuclides, the modeling approach is potentially useful for exploring the coupling of microbial growth and geochemical reactions in a variety of other basic and applied biotechnology research settings.

Cancer risk management practices of non-carriers within BRCA1/2 mutation positive families in the Kathleen Cunningham Consortium for Research into Familial Breast Cancer (kConFab)

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Background: This study prospectively evaluated risk management practices of true BRCA1/2 negative women. Methods: A questionnaire was mailed to 471 non-carriers from mutation positive families 3 years after their enrolment in the kConFab breast cancer (BC) family cohort study. Women who had received their mutation result had pre-test counselling and result disclosure in one of 16 Family Cancer Clinics nationwide. Undertaking mammography more often than 2 yearly (Australian population guidelines), clinical breast examination (CBE) more often than yearly, breast self-examination (BSE) more often than monthly and any trans-vaginal ultrasound (TVU) or CA-125 was considered over screening. Linear logistic regression was used to identify factors (age, marital status, education, parity, ethnicity, place of residence, time since disclosure of result, family history) associated with over screening. Results: 347 women responded (74%); 260 were excluded from this analysis (self-reported not knowing their mutation status, 207; uninformative screening data due to proximity of result disclosure to questionnaire administration, 47; developed cancer, 3; pregnancy, 3), leaving 87 subjects. Mean follow up was 4.4 years. Proportions over-screening were; mammography 53%, CBE 10%, BSE 11%, TVU 10% and CA125 10%. No measured factor was associated with over-utilization of BC screening. Women with > one relative with OC were significantly more likely to over-utilize TVU (OR 8.1, CI 1.6–42 P=0.01) and CA125 (OR 19.6, CI 3.1–121 P=0.001) compared to women with ≤ one relative with OC. One woman underwent bilateral mastectomy and 1 bilateral oophorectomy; none used chemoprevention. Conclusions: A major benefit of learning one′s negative mutation status is that the intensity of risk management practices can be reduced to that appropriate for the general population. However, non-carriers with a strong family history of OC tend to inappropriately use OC screening. The reasons are unclear but need elucidation given the potential for harm. The reasons for over-utilization of mammography in 53% also warrant further study.

No significant financial relationships to disclose.

Comparison of the lateral release rates in the press fit condylar prosthesis and the PFC Sigma prosthesis

There are many different total knee replacements on the market. Most have undergone design changes since they were introduced. The manufacturers claim these changes are necessary to improve outcomes of their products. Johnson and Johnson changed their press fit condylar (PFC) knee to PFC Sigma. One of the reasons for the change was to improve patella tracking by combining the deeply radiused trochlear groove of the PFC cruciate sacrificing knee with the natural asymmetrical valgus angle of the PFC cruciate retaining knee. In 1995 we started a prospective audit of our knee replacements. We analysed our early outcomes to test this theory. Group 1 consisted of 468 patients who underwent 543 PFC replacements. Group 2 consisted of 359 patients who underwent 423 Sigma knee replacements. An audit nurse saw all the patients preoperatively and an American Knee Society Score was done. Operative details were recorded. Patients were followed up by an audit nurse at a dedicated knee clinic. The same surgeons using the same instrumentation carried out the operations. The change in design reduced the lateral release rate by 50% from 32 to 16%. The complications were similar in both groups and there was no difference in the outcomes at 6 months. The change in design from the PFC to the Sigma knee has had an effect in reducing the lateral release rate, without affecting the early outcomes. We plan to continue this audit to see if the change leads to less patellar problems in the future.

Generation of full-length cDNA libraries enriched for differentially expressed genes for functional genomics

Here, we describe the application of a RecA-based cloning technology to generate full-length cDNA libraries enriched for genes that are differentially expressed between tumor and normal tissue samples. First, we show that the RecA-based method can be used to enrich cDNA libraries for several target genes in a single reaction. Then, we demonstrate that this method can be extended to enrich a cDNA library for many full-length cDNA clones using fragments derived from a subtracted cDNA population. The results of these studies show that this RecA-mediated cloning technology can be used to convert subtracted cDNAs or a mixture of several cDNA fragments corresponding to differentially expressed genes into a full-length library in a single reaction. This procedure yields a population of expression-ready clones that can be used for further high-throughput functional screening.

The quality of surgical information on the Internet

The quality of surgical information on the Internet is variable. Content variation limits the use of the Internet as a reliable and safe information source both for both health professionals and patients. Medical information is a particularly sensitive area. Incorrect or misleading information may lead to potentially dangerous health behaviour, patients reading information intended for health professionals may misunderstand information or may get wrong expectations regarding treatment options.

Variable budgeting for staffing. Analysis and evaluation

A successful resource-management system must be based on variable budgeting principles to account for fluctuation in patient census, methodically prepared through historical analysis of operations, carefully executed and monitored by accountable multidisciplinary managers. Significant attention must be paid to communication, positioning and stability of the patient care organization.

Experience with germ cell tumors of testicle at University of Iowa

Between 1964 and 1979, 219 patients with germ cell testicular tumors were treated at the University of Iowa. In 79 nonseminomatous germ cell tumors various chemotherapeutic regimens were used. The response, salvage, and survival rates are compared. There is a definite trend toward better response rates and survival using the combination cisplatinum, vinblastine (Velban), and bleomycin. With this combination, 75 per cent of Stage II and III patients survived two years. The over-all response rate was 85 per cent, and 87 per cent of those with a complete response survived two years. Eighty per cent of deaths occurred within two years and 90 per cent within three years.