First Superferromagnetic Remanence Characterization and Scan Optimization for Super-Resolution Magnetic Particle Imaging.

Magnetic particle imaging (MPI) is a sensitive, high-contrast tracer modality that images superparamagnetic iron oxide nanoparticles, enabling radiation-free theranostic imaging. MPI resolution is currently limited by scanner and particle constraints. Recent tracers have experimentally shown 10× resolution and signal improvements with dramatically sharper M-H curves. Experiments show a dependence on interparticle interactions, conforming to literature definitions of superferromagnetism. We thus call our tracers superferromagnetic iron oxide nanoparticles (SFMIOs). While SFMIOs provide excellent signal and resolution, they exhibit hysteresis with non-negligible remanence and coercivity. We provide the first quantitative measurements of SFMIO remanence decay and reformation using a novel multiecho pulse sequence. We characterize MPI scanning with remanence decay and coercivity and describe an SNR-optimized pulse sequence for SFMIOs under human electromagnetic safety limitations. The resolution from SFMIOs could enable clinical MPI with 10× reduced scanner selection fields, reducing hardware costs by up to 100×.

Chinese university students' help-seeking behaviors when faced with mental health challenges.

BACKGROUND: Mental illnesses and mental health challenges have become increasingly pervasive among Chinese university students. However, the utilization rate of mental health services is low among students. AIMS: We aimed to explore Chinese university students' help-seeking behaviors to understand how they deal with mental health challenges and use the results to inform the development of effective mental health promotion initiatives. METHODS: In this study, we conducted 13 focus group interviews with students in six universities in Jinan, China, including 91 (62%) female students and 56 (38%) male students. We drew on the Theory of Planned Behaviors to guide our thematic analysis to gain a contextual understanding of participants' accounts on help-seeking. RESULTS: Our results have depicted the help-seeking patterns of Chinese university students and show that there are four major behaviors which are self-reliance, seeking support from peers and families, seeking professional support, and accessing virtual mental health care. CONCLUSION: Results from this study can be used to inform the development of mental health literacy programming for students in universities that share similar contexts, and the study has also opened up a new space for using qualitative approaches to study mental health needs and access to care in diverse populations.

Height-based formulas for predicting intravascular length of tunnelled neck central venous catheter in paediatric population.

INTRODUCTION: Central venous catheter (CVC) placement is commonly performed in children. We aim to develop simple formulas to predict CVC intravascular length to minimise radiation exposure associated with the procedure. METHODS: 124 paediatric patients who received tunnelled neck CVCs and subsequent CT thorax at Hong Kong Children's Hospital from January 2020 to July 2022 were reviewed retrospectively. Formula development cohorts were subdivided by insertion sites-9 right external jugular vein (REJV), 41 right internal jugular vein (RIJV), 14 left external jugular vein (LEJV), 10 left internal jugular vein (LIJV). Using measurements from CT by two radiologists, formulas predicting the CVC intravascular length based on height and insertion sites were developed using a linear regression model. These formulas were tested with validation cohorts (10 randomly selected cases in REJV and RIJV groups respectively). Validation cohorts were not available for LEJV and LIJV groups due to small sample sizes. RESULT: The goodness-of-fit (R^2) of all formulas are above 0.8. In the validation cohorts, the REJV formula was predictive of intravascular CVC length within 1 cm in 70% of CVC with mean absolute difference of 0.63 cm (SD 0.48 cm), and the RIJV formula was predictive of intravascular CVC length within 1 cm in 80% of CVC with mean absolute difference of 0.67 cm (SD 0.53 cm). CONCLUSION: Intravascular CVC length can be estimated using simple formulas based on height and insertion sites. Further prospective validation of the LEJV and LIJV formulas is needed.

Multimodality imaging of developmental splenic anomalies: tips and pitfalls.

Anomalies in number and location may occur during splenic development. This review aims to offer a brief overview of splenic function and embryology and a detailed account of the imaging appearances using different imaging techniques of the normal spleen and various congenital splenic anomalies including (1) abnormal viscero-atrial situs, (2) splenogonadal fusion, (3) intrapancreatic accessory spleen, (4) wandering spleen, and (5) splenosis. Emphasis is placed on the salient features that help radiologists recognise important associations (e.g., asplenia/polysplenia in situs abnormalities), avoid diagnostic pitfalls (e.g., mistaking intrapancreatic accessory spleen as pancreatic neoplasms), and potential complications (e.g., acute torsion in wandering spleen). The correct identification of the said anomalies from more sinister causes, such as malignancies, are essential, where early intervention is necessary.

Combining magnetic particle imaging and magnetic fluid hyperthermia for localized and image-guided treatment.

Magnetic fluid hyperthermia (MFH) has been widely investigated as a treatment tool for cancer and other diseases. However, focusing traditional MFH to a tumor deep in the body is not feasible because the in vivo wavelength of 300 kHz very low frequency (VLF) excitation fields is longer than 100 m. Recently we demonstrated that millimeter-precision localized heating can be achieved by combining magnetic particle imaging (MPI) with MFH. In principle, real-time MPI imaging can also guide the location and dosing of MFH treatments. Hence, the combination of MPI imaging plus real time localized MPI-MFH could soon permit closed-loop high-resolution hyperthermia treatment. In this review, we will discuss the fundamentals of localized MFH (e.g. physics and biosafety limitations), hardware implementation, MPI real-time guidance, and new research directions on MPI-MFH. We will also discuss how the scale up to human-sized MPI-MFH scanners could proceed.

Adapting re-usable elastomeric respirators to utilise anaesthesia circuit filters using a 3D-printed adaptor - a potential alternative to address N95 shortages during the COVID-19 pandemic.

The COVID-19 pandemic has increased the demand for disposable N95 respirators. Re-usable elastomeric respirators may provide a suitable alternative. Proprietary elastomeric respirator filters may become depleted as demand increases. An alternative may be the virus/bacterial filters used in anaesthesia circuits, if they can be adequately fitted onto the elastomeric respirators. In addition, many re-usable elastomeric respirators do not filter exhaled breaths. If used for sterile procedures, this would also require modification. We designed a 3D-printed adaptor that permits elastomeric respirators to interface with anaesthesia circuit filters and created a simple modification to divert exhaled breaths through the filter. We conducted a feasibility study evaluating the performance of our modified elastomeric respirators. A convenience sample of eight volunteers was recruited. Quantitative fit testing, respiratory rate and end-tidal carbon dioxide were recorded during fit testing exercises and after 1 h of wear. All eight volunteers obtained excellent quantitative fit testing throughout the trial. The mean (SD) end-tidal carbon dioxide was 4.5 (0.5) kPa and 4.6 (0.4) kPa at baseline and after 1 h of wear (p = 0.148). The mean (SD) respiratory rate was 17 (4) breaths.min-1 and 17 (3) breaths.min-1 at baseline and after 1 h of wear (p = 0.435). Four out of eight subjects self-reported discomfort; two reported facial pressure, one reported exhalation resistance and one reported transient dizziness on exertion. Re-usable elastomeric respirators to utilise anaesthesia circuit filters through a 3D-printed adaptor may be a potential alternative to disposable N95 respirators during the COVID-19 pandemic.

Liver-specific knockdown of long-chain acyl-CoA synthetase 4 reveals its key role in VLDL-TG metabolism and phospholipid synthesis in mice fed a high-fat diet.

Long-chain acyl-CoA synthetase 4 (ACSL4) has a unique substrate specificity for arachidonic acid. Hepatic ACSL4 is coregulated with the phospholipid (PL)-remodeling enzyme lysophosphatidylcholine (LPC) acyltransferase 3 by peroxisome proliferator-activated receptor δ to modulate the plasma triglyceride (TG) metabolism. In this study, we investigated the acute effects of hepatic ACSL4 deficiency on lipid metabolism in adult mice fed a high-fat diet (HFD). Adenovirus-mediated expression of a mouse ACSL4 shRNA (Ad-shAcsl4) in the liver of HFD-fed mice led to a 43% reduction of hepatic arachidonoyl-CoA synthetase activity and a 53% decrease in ACSL4 protein levels compared with mice receiving control adenovirus (Ad-shLacZ). Attenuated ACSL4 expression resulted in a substantial decrease in circulating VLDL-TG levels without affecting plasma cholesterol. Lipidomics profiling revealed that knocking down ACSL4 altered liver PL compositions, with the greatest impact on accumulation of abundant LPC species (LPC 16:0 and LPC 18:0) and lysophosphatidylethanolamine (LPE) species (LPE 16:0 and LPE 18:0). In addition, fasting glucose and insulin levels were higher in Ad-shAcsl4-transduced mice versus control (Ad-shLacZ). Glucose tolerance testing further indicated an insulin-resistant phenotype upon knockdown of ACSL4. These results provide the first in vivo evidence that ACSL4 plays a role in plasma TG and glucose metabolism and hepatic PL synthesis of hyperlipidemic mice.

Prognostic significance of genetic biomarkers in isocitrate dehydrogenase-wild-type lower-grade glioma: the need to further stratify this tumor entity - a meta-analysis.

The clinical outcomes of isocitrate dehydrogenase-wild-type (IDH-wt) lower-grade glioma (LGG) have been the subject of debate for some time. In this meta-analysis, we aimed to assess the prognostic values of several known genetic markers (e.g. TERT promoter mutation, H3F3A mutation, CDKN2A loss) in this tumor group. Four electronic databases, including PubMed, Scopus, Web of Science and Virtual Health Library, were searched for relevant articles. Pooled hazard ratio (HR) and corresponding 95% confidence interval (CI) for overall survival were calculated using a random-effect model weighted by an inverse variance method. A total of 11 studies were finally selected from 2274 articles for meta-analyses. Several genetic alterations were demonstrated to have a negative impact on prognosis of IDH-wt LGGs, specifically TERT promoter mutation (HR, 1.96; 95% CI, 1.42-2.70), H3F3A mutation (HR, 3.21; 95% CI, 1.86-5.55) and EGFR amplification (HR, 1.67; 95% CI, 1.02-2.74). However, CDKN loss, ATRX mutation and coexisting gain of chromosome 7/loss of chromosome 10 showed no clinical significance in this glioma entity. Our study results demonstrated that IDH-wt LGGs are heterogeneous in clinical outcome and not all tumors have a poor prognosis. The presence of TERT promoter mutation, H3F3A mutation and EGFR amplification showed negative prognostic impacts in this tumor entity. These genetic events can be used to better stratify patient outcomes.

The bridge between transplantation and regenerative medicine: Beginning a new Banff classification of tissue engineering pathology.

The science of regenerative medicine is arguably older than transplantation-the first major textbook was published in 1901-and a major regenerative medicine meeting took place in 1988, three years before the first Banff transplant pathology meeting. However, the subject of regenerative medicine/tissue engineering pathology has never received focused attention. Defining and classifying tissue engineering pathology is long overdue. In the next decades, the field of transplantation will enlarge at least tenfold, through a hybrid of tissue engineering combined with existing approaches to lessening the organ shortage. Gradually, transplantation pathologists will become tissue-(re-) engineering pathologists with enhanced skill sets to address concerns involving the use of bioengineered organs. We outline ways of categorizing abnormalities in tissue-engineered organs through traditional light microscopy or other modalities including biomarkers. We propose creating a new Banff classification of tissue engineering pathology to standardize and assess de novo bioengineered solid organs transplantable success in vivo. We recommend constructing a framework for a classification of tissue engineering pathology now with interdisciplinary consensus discussions to further develop and finalize the classification at future Banff Transplant Pathology meetings, in collaboration with the human cell atlas project. A possible nosology of pathologic abnormalities in tissue-engineered organs is suggested.

The impact of seasonal operating room closures on wait times for oral cancer surgery.

BACKGROUND: Operating room slowdowns occur at specific intervals in the year as a cost-saving measure. We aim to investigate the impact of these slowdowns on the care of oral cavity cancer patients at a Canadian tertiary care centre. METHODS: A total of 585 oral cavity cancer patients seen between 1999 and 2015 at the London Health Science Centre (lhsc) Head and Neck Multidisciplinary Clinic were included in this study. Operating room hours and patient load from 2006 to 2014 were calculated. Our primary endpoint was the wait time from consultation to definitive surgery. Exposure variables were defined according to wait time intervals occurring during time periods with reduced operating room hours. RESULTS: Overall case volume rose significantly from 2006 to 2014 (p < 0.001), while operating room hours remained stable (p = 0.555). Patient wait times for surgery increased from 16.3 days prior to 2003 to 25.5 days in 2015 (p = 0.008). Significant variability in operating room hours was observed by month, with lowest reported for July and August (p = 0.002). The greater the exposure to these months, the more likely patients were to wait longer than 28 days for surgery (odds ratio per day [or]: 1.07, 95% confidence interval [ci]: 1.05 to 1.10, p < 0.001). Individuals seen in consultation preceding a month with below average operating room hours had a higher risk of disease recurrence and/or death (hazard ratio [hr]: 1.59, 95% ci: 1.10 to 2.30, p = 0.014). CONCLUSIONS: Scheduled reductions in available operating room hours contribute to prolonged wait times and higher disease recurrence. Further work is needed to identify strategies maximizing efficient use of health care resources without negatively affecting patient outcomes.

Metformin and breast cancer stage at diagnosis: a population-based study.

PURPOSE: The objective of the present study was to use a large, population-based cohort to examine the association between metformin and breast cancer stage at diagnosis while accounting for mammography differences. METHODS: We used data from Ontario administrative health databases to identify women 68 years of age or older with diabetes and invasive breast cancer diagnosed from 1 January 2007 to 31 December 2012. Adjusted logistic regression models were used to compare breast cancer stage at diagnosis (stages i and ii vs. iii and iv) between the women exposed and not exposed to metformin. We also examined the association between metformin use and estrogen receptor status, tumour size, and lymph node status in the subset of women for whom those data were available. RESULTS: We identified 3125 women with diabetes and breast cancer; 1519 (48.6%) had been exposed to metformin before their cancer diagnosis. Median age at breast cancer diagnosis was 76 years (interquartile range: 72-82 years), and mean duration of diabetes was 8.8 ± 5.9 years. In multivariable analyses, metformin exposure was not associated with an earlier stage of breast cancer (odds ratio: 0.98; 95% confidence interval: 0.81 to 1.19). In secondary analyses, metformin exposure was not associated with estrogen receptor-positive breast cancer, tumours larger than 2 cm, or positive lymph nodes. CONCLUSIONS: This population-based study did not show an association between metformin use and breast cancer stage or tumour characteristics at diagnosis. Our study considered older women with long-standing diabetes, and therefore further studies in younger patients could be warranted.

Development of an online, patient-centred decision aid for patients with oropharyngeal cancer in the transoral robotic surgery era.

BACKGROUND: Radiotherapy (rt) has been the standard treatment for early oropharyngeal cancer, achieving excellent outcomes, but with significant toxicities. Transoral robotic surgery (tors) has emerged as a promising alternative. A decision aid (da) can help to establish patient treatment preferences. METHODS: A da was developed and piloted in 40 healthy adult volunteers. Assuming equal oncologic outcomes of the treatments, participants indicated their preference. The treatment trade-off point was then established, and participant perceptions were elicited. RESULTS: More than 80% of participants initially selected tors for treatment, regardless of facilitator background. For all participants, the treatment trade-off point changed after an average 15% cure benefit. Treatment toxicities, duration, novelty, and perceptions all influenced treatment selection. All subjects valued the da. CONCLUSIONS: A da developed for early oropharyngeal cancer treatment holds promise in the era of shared decision-making. Assuming equal cure rates, tors was preferred over rt by healthy volunteers.

Factors associated with postpartum psychiatric admission in a population-based cohort of women with schizophrenia.

OBJECTIVE: We aimed to identify factors associated with postpartum psychiatric admission in schizophrenia. METHOD: In a population-based cohort study of 1433 mothers with schizophrenia in Ontario, Canada (2003-2011), we compared women with and without psychiatric admission in the 1st year postpartum on demographic, maternal medical/obstetrical, infant and psychiatric factors and identified factors independently associated with admission. RESULTS: Admitted women (n = 275, 19%) were less likely to be adolescents, more likely to be low income and less likely to have received prenatal ultrasound before 20 weeks gestation compared to non-admitted women. They also had higher rates of predelivery psychiatric comorbidity and mental health service use. Factors independently associated with postpartum admission were age (<20 vs. ≥35 years: adjusted risk ratio, aRR, 0.48, 95% CI 0.24-0.96), income (lowest vs. highest income: aRR 1.67, 1.13-2.47) and the following mental health service use factors in pregnancy: admission (≥35 days/year vs. no days, aRR 4.54, 3.65-5.65), outpatient mental health care (no visits vs. ≥2 visits aRR 0.35, 0.27-0.47) and presence of a consistent mental health care provider during pregnancy (aRR 0.69, 0.54-0.89). CONCLUSION: Certain subgroups of women with schizophrenia may benefit from targeted intervention to mitigate risk for postpartum admission.

Clinical transition for adolescents with developmental disabilities in Hong Kong: a pilot study.

INTRODUCTION: Children with developmental disabilities usually move from the paediatric to adult health service after the age of 18 years. This clinical transition is fragmented in Hong Kong. There are no local data for adolescents with developmental disabilities and their families about the issues they face during the clinical transition. This pilot study aimed to explore and collect information from adolescents with developmental disabilities and their caregivers about their transition from paediatric to adult health care services in Hong Kong. METHODS: This exploratory survey was carried out in two special schools in Hong Kong. Convenient samples of adolescents with developmental disabilities and their parents were taken. The questionnaire was administered by interviewers in Cantonese. Descriptive statistics were used to analyse the answers to closed-ended questions. Responses to open-ended questions were summarised. RESULTS: In this study, 22 parents (mean age ± standard deviation: 49.9 ± 10.0 years) and 13 adolescents (19.6 ± 1.0 years) completed the face-to-face questionnaire. The main diagnoses of the adolescents were cerebral palsy (59%) and cognitive impairment (55%). Of the study parents, 77% were reluctant to transition. For the 10 families who did move to adult care, 60% of the parents were not satisfied with the services. The main reasons were reluctant to change and dissatisfaction with the adult medical service. The participants emphasised their need for a structured clinical transition service to support them during this challenging time. CONCLUSIONS: This study is the first in Hong Kong to present preliminary data on adolescents with developmental disabilities and their families during transition from paediatric to adult medical care. Further studies are required to understand the needs of this population group during clinical transition.

Topological edge plasmon modes between diatomic chains of plasmonic nanoparticles.

We study the topological edge plasmon modes between two "diatomic" chains of identical plasmonic nanoparticles. Zak phase for longitudinal plasmon modes in each chain is calculated analytically by solutions of macroscopic Maxwell's equations for particles in quasi-static dipole approximation. This approximation provides a direct analogy with the Su-Schrieffer-Heeger model such that the eigenvalue is mapped to the frequency dependent inverse-polarizability of the nanoparticles. The edge state frequency is found to be the same as the single-particle resonance frequency, which is insensitive to the separation distances within a unit cell. Finally, full electrodynamic simulations with realistic parameters suggest that the edge plasmon mode can be realized through near-field optical spectroscopy.

Axonal myelin increase in the callosal genu in depression but not schizophrenia.

BACKGROUND: Abnormalities in the anterior inter-hemispheric connectivity have previously been implicated in major depressive disorder. Disruptions in fractional anisotropy in the callosum and fornix have been reported in schizophrenia and major depressive disorder. Oligodendrocyte density and overall size of the callosum and fornix show no alteration in either illness, suggesting that gross morphology is unchanged but more subtle organizational disruption may exist within these brain regions in mood and affective disorders. METHOD: Using high-resolution oil-immersion microscopy we examined the cross-sectional area of the nerve fibre and the axonal myelin sheath, and using standard high-resolution light microscopy we measured the density of myelinated axons. These measurements were made in the genu of the corpus callosum and the medial body of the fornix at its most dorsal point. Measures were taken in the sagittal plane in the callosal genu and in the coronal plane at the most dorsal part of the fornix body. RESULTS: Cases of major depressive disorder had significantly greater mean myelin cross-sectional area (p = 0.017) and myelin thickness (p = 0.004) per axon in the genu than in control or schizophrenia groups. There was no significant change in the density of myelinated axons, and no changes observed in the fornix. CONCLUSION: The results suggest a clear increase of myelin in the axons of the callosal genu in MDD, although this type of neuropathological study is unable to clarify whether this is caused by changes during life or has a developmental origin.