The rate of iatrogenic injuries in surgical patients appears resistant to multiple interventions: what can we learn from aviation safety?

BACKGROUND: This project analyses all iatrogenic injuries from our department over the last decade and tracks their rate against several interventions. METHODS: All patients who sustained an iatrogenic injury between 2012 and 2022 were reviewed. RESULTS: A total of 946 iatrogenic injuries occurred in 731 patients. Sixty per cent of these patients were male; the median age was 39 years. Of 946 injuries, 574 (60.7%) occurred during an operation, and 372 (39.3%) were not related to an operation. Of the operative injuries 412 (71.8%) were enteric injuries. Of the 372 non-operative iatrogenic injuries 304 (82%) were due to indwelling devices (ID), and 34 (10%) occurred during flexible endoscopy. Fifty-five per cent of the injuries due to ID were due to central venous catheters (CVC) and urinary catheters (UC). CVC contributed toward 31% of all non-operation related iatrogenic injuries. One in 54 admissions (946/51 178) and one in 47 (574 /27 342) patients undergoing an operation sustained an iatrogenic injury. The annual rate of iatrogenic injuries did not decrease over the decade despite a multifaceted approach to reduce them. Interventions included electronic database development, procedural standardisation, and checklist implementation. CONCLUSION: Despite multiple interventions over a decade, our rate of iatrogenic injury remains constant. Ongoing multifaceted efforts to reduce this rate must focus on engendering a culture of safety at all levels of healthcare if we hope to match the enviable safety record of the aeronautics industry.

Dialectical behaviour therapy: effect of a coordinated implementation approach on programme sustainability.

Sustainability of DBT programmes and the factors which potentially influence this has received little attention from researchers. In this article, we review the literature reporting on sustainability of DBT programmes in outpatient settings. We also seek to advance the limited knowledge on this topic by reporting on the sustainability of DBT programmes delivered by teams that trained via a coordinated implementation approach in Ireland. As part of this perspective piece we conducted a systematic literature search which identified four studies reporting on DBT programme sustainability. All four reported on programmes delivered by teams that had received training as per the DBT Intensive Training Model. The findings of these studies are summarised and we consider the effect on DBT programme sustainability of introducing a coordinated implementation approach in Ireland.

Who tells the story of burns in low-and-middle income countries? - A bibliometric study.

INTRODUCTION: Low- and middle-income countries (LMICs) remain drastically underrepresented in health research, with African countries producing less than 1% of the global output. This work investigates authorship patterns of publications on burns in LMICs. Original research studies addressing burn injuries in LMICs and published between 1st January 2015 and 31st December 2020 were included in the review. Descriptive statistics were performed for country affiliations of authors, World Bank Country Income Groups, WHO group, study-focus and country studied. Of the 458 results, 426 studies met the inclusion criteria. Nearly a quarter of papers on burns in LMICs had both first and senior authors from high-income countries (HICs, n = 95, 24.4%), more than half of the papers had both first and senior authors from upper middle- income countries (upper MICs, n = 222, 57.2%), while less than 1% (n = 3) had first and senior authors exclusively from lower-income countries (LICs). Eleven percent (n = 41/388) of all papers were written without either first nor senior author being from the country studied, and 17 of them (41%) had both first and senior authors from the USA. Twenty-five (6%) of the papers had the first author and not the senior author from the country of focus, while six (2%) had the senior and not the first author from the country of interest. To overcome global health challenges such as burns, locally led research is imperative. The maximum benefit of HIC-LMIC collaborations is achieved when LMICs play an active role in leading the research. When LMICs direct the research being conducted in their country, the harm of inherently inequitable relationships is minimized.

A practical formula for fluid resuscitation in acute paediatric burns in a low resource setting: A pilot study.

BACKGROUND: Appropriate fluid resuscitation of acute burn injury is critical and there are recognized challenges with fluid resuscitation, including those with relevance to low resource settings. We developed a practical protocol that guides burn resuscitation and sought to evaluate the safety of our modified resuscitation formula through a small pilot study that particularly addresses the problems we have experienced in a low resource setting. METHODS: Children with burns more than 15% total body surface area admitted within 24 h of injury to Edendale Hospital between 1 June 2021 and 31 August 2021 were included. The resuscitation formula used was 2 mls of Ringers Lactate per bodyweight in kilograms per% total body surface area (TBSA) given over 24 h and adjusted according to urine output. Data analysed included age, weight, mechanism, TBSA, hours post burn at presentation to hospital, total fluid given in the first 24 h of admission, total urine output in the first 24 h of admission, number of fluid adjustments made during the first 24 h and complications related to fluid resuscitation. RESULTS: Ten children were included. The median age was 3 (IQR 2-5) years old, with a mean weight of 14.9 (SD 5.07) kilograms, a median TBSA of 17.4 (IQR 16-26)%, presenting at a median of 12 (6.5-18) hours post burn injury. Mechanism of burn was scald in all cases, with 9 being hot water and hot food in one. In the first 24 h a mean of 2.05 (SD 0.58) mls/kg of fluid was received with a mean urine output of 1.66 (SD 0.57) mls/kg/hr. CONCLUSION: The results of this pilot study to evaluate the safety of our protocol seem reasonable. It is limited by the lack of larger injuries as well as adult patients and a larger prospective study is pertinent.

Adverse events associated with the use of indwelling devices in surgical patients.

BACKGROUND: Indwelling devices (IDs) are ubiquitous in modern healthcare and may often be associated with morbidity. This paper investigates adverse events related to IDs in surgical patients, which are generally placed into patients either to administer therapy, manage outputs or for specific therapeutic benefit. METHODS: A retrospective electronic database-based assessment of all adverse events relating to IDs was undertaken from December 2012 to August 2021. All events were categorised by device type, event type, and event severity. RESULTS: A total of 11 130 morbidities were captured over the study period. Of those, 2 195 entries pertained to an ID with 2 402 reported adverse events affecting 1 592 patients. Two-thirds occurred in males and injuries occurred in patients age ranging from eight days to 93 years, with an average age of 36 years. The most frequently implicated devices were surgical drains (including intercostal chest drains), accounting for 491 (20.44%) of adverse events. Central venous catheters (CVCs) and intravenous cannulae were involved in 374 (15.57%) and 332 (13.83%) events, respectively. Unplanned removal (346, 13.91%), output not measured (319, 12.82%), injury (314, 12.62%), and blockage (279, 11.21%) were the most common error types. The majority of adverse events were considered minor, however 27 (1.1%) patients experienced organ dysfunction as a result of an ID-related adverse event, and seven (0.3%) died. CONCLUSIONS: Morbidity related to IDs in surgical patients is a relatively frequent occurrence. Standardisation of ID insertion and care, staff education, and improvements in communication have been identified as the most important strategies by which we can limit error-associated morbidity in patients with IDs.

Associations of a liver health index with health, milk yield, and reproductive performance in dairy herds in the northeastern United States.

The objective was to evaluate a liver health index (LHI) by evaluating its association with negative health events, milk yield, and risk of pregnancy within 150 d in milk (DIM). In a retrospective cohort study, an LHI was calculated based on plasma albumin, cholesterol, and bilirubin concentrations for 265 primiparous and 611 multiparous cows 3 to 12 DIM enrolled across 72 farms in the northeastern United States. Mixed effects linear regression models were used to evaluate if (1) metritis (MET), (2) displaced abomasum (DA), (3) clinical ketosis (CK), (4) one or more of the 3 disorders (MET, DA, or CK), (5) 2 or more of the 3 disorders (MET, DA, or CK), or (6) culling within 30 DIM was associated with LHI. Mixed effects linear regression models were used to evaluate if LHI was associated with 305-d mature equivalent milk at the fourth test day (ME305; mean ± standard deviation: 114 ± 13 DIM) and a Cox proportional hazards model was used to evaluate if LHI was associated with pregnancy within 150 DIM. Cows that were diagnosed with MET, DA, CK, one or more of the disorders, 2 or more of the disorders, or were culled within 30 DIM had a lower LHI than cows that were not diagnosed with a disorder or culled. A 1-unit increase in LHI was associated with a 154 ± 38 kg increase in ME305 and a 8% increased risk of pregnancy within 150 DIM [hazard ratio (95% confidence interval): 1.08 (1.03 to 1.14)] for multiparous cows; however, we did not identify a relationship between LHI and ME305 or pregnancy within 150 DIM for primiparous cows. These results suggest that the LHI is associated with health, milk yield, and pregnancy within 150 DIM for multiparous cows and health for primiparous cows; therefore, the LHI can be used as a tool to evaluate transition cow success.

Transition cow nutrition and management strategies of dairy herds in the northeastern United States: Part II-Associations of metabolic- and inflammation-related analytes with health, milk yield, and reproduction.

The objectives were as follows: (1) establish cow-level thresholds for prepartum nonesterified fatty acids (NEFA) and postpartum NEFA, ß-hydroxybutyrate (BHB), and haptoglobin (Hp) concentrations associated with negative health events; (2) evaluate cow-level associations between biomarkers and 305-d mature equivalent milk at the fourth test day (ME305) and reproductive performance; and (3) identify herd-alarm levels (proportion of cows sampled above the critical threshold) for biomarkers that are associated with herd-level changes in disorder incidence (displaced abomasum and clinical ketosis), reproductive performance, and ME305. In a prospective cohort study, 1,473 cows from 72 farms were enrolled from the northeastern United States. Blood samples were collected from the same 11 to 24 cows per herd during the late-prepartum and early-postpartum periods. Whole blood was analyzed for postpartum BHB concentrations; plasma was analyzed for prepartum and postpartum NEFA and postpartum Hp concentrations. Critical thresholds for the biomarkers associated with health events for all cows were established using a receiver operating characteristic curve analysis. Poisson, linear mixed effects, and Cox proportional hazards models investigated the association of the biomarkers with health and performance. The prepartum NEFA and Hp threshold associated with culling was ≥0.17 mmol/L and 0.45 g/L, respectively. The postpartum NEFA and BHB thresholds associated with diagnosis of metritis, displaced abomasum, or clinical ketosis were ≥0.46 mmol/L and ≥0.9 mmol/L, respectively. Multiparous cows with prepartum NEFA concentration ≥0.17 mmol/L produced 479 kg less ME305. Multiparous and primiparous cows with postpartum NEFA concentration ≥0.46 mmol/L produced 280 kg less and 446 kg more ME305, respectively. Cows with BHB concentration ≥0.9 and ≥1.1 mmol/L produced 552 kg more ME305 and had a 20% decreased risk of pregnancy within 150 d in milk, respectively; however, multiparous cows with BHB concentration ≥1.5 mmol/L produced 376 kg less ME305. Cows with Hp concentration ≥0.45 g/L produced 492 kg less ME305 and had 28% decreased risk of pregnancy within 150 DIM. Cows with Hp concentration ≥0.45 g/L had 19% decreased pregnancy risk to first service (PRFS). Herds above the herd-alarm levels for prepartum NEFA had a 6.0-percentage unit increase in disorder incidence and a 6.0-percentage unit decrease in 21-d pregnancy rate (PR) for multiparous cows, a 3.9-percentage unit increase in PR and a 5.8-percentage unit increase in the probability of pregnancy for primiparous cows. Herds above the herd-alarm levels for postpartum NEFA had a 5.8- and 4.2-percentage unit increase in disorder incidence for multiparous and primiparous cows, respectively, a 789 kg decrease in ME305 for multiparous cows, and a 6.8- and 6.3-percentage unit decrease and increase in PR and PRFS for multiparous cows, respectively. Herds above the herd-alarm levels for BHB had an 8.5-percentage unit increase in disorder incidence, a 332 and 229 kg increase in ME305 for primiparous and multiparous cows, respectively, and a 3.2-, 5.2-, and 7.0-percentage unit decrease in PR, probability of pregnancy, and PRFS, respectively. Herds above the herd-alarm levels for postpartum Hp had a 5.3-percentage unit increase in disorder incidence. At the cow level and herd level, elevated biomarker concentrations were associated with an increased disorder risk and varied performance responses.

Amputations secondary to burn injuries in a resource-limited setting.

INTRODUCTION: Amputations are a devastating consequence of severe burns. Amputations in a resource-limited setting are challenging as rehabilitation services available to these patients are inconsistent and often fragmented. Epileptic patients are a particularly vulnerable group when it comes to burn-injuries and often sustain deeper burns. The aim of this study is to analyse amputations secondary to burn injuries. We seek to identify vulnerable groups as a means for advocacy efforts to reduce the devastation of an amputation secondary to a burn injury. This paper highlights the burden of these injuries on the healthcare system and emphasizes the need for additional trained therapists for the rehabilitation of these patients. METHODS: A retrospective database review was conducted. All burns admissions who underwent an amputation between 1 February 2016 and 31 January 2019 were considered. RESULTS: A total of 1575 patients were admitted during the study period. Fifty-four percent of the admissions were paediatric patients. The amputation rate in the paediatric population was 1.5% (13/850) while in the adult population it was 4.8% (35/724) . Most paediatric amputations were as a result of electrical injuries. Flame burns were most likely to result in amputations in the adult group and convulsions were the leading circumstance leading to the injury. There was no significant difference in sepsis or length of stay between the groups. There were no mortalities in the paediatric group but there was an 11% mortality rate in the adult group. CONCLUSION: The incidence of amputations in burns is low, however, it remains a devastating morbidity. Epileptics are a vulnerable group and these patients account for the most amputations among adult burns patients. Education interventions are needed regarding their diagnosis, administration of their medication and the importance of compliance. Advocacy efforts to ensure constant supply of anti-epileptic drugs at the clinics and other district level health facilities is also essential. Electrical injuries in children are not as common as hot water scalds, however, they are more likely to result in amputation. Communities need to be informed of the risk associated with illegal electrical connections and initiatives need to drive the safe provision of affordable electricity to these under-privileged, vulnerable communities.

Ultrafast Loss of Lattice Coherence in the Light-Induced Structural Phase Transition of V_{2}O_{3}.

In solids, the response of the lattice to photoexcitation is often described by the inertial evolution on an impulsively modified potential energy surface which leads to coherent motion. However, it remains unknown if vibrational coherence is sustained through a phase transition, during which coupling between modes can be strong and may lead to rapid loss of coherence. Here we use coherent phonon spectroscopy to track lattice coherence in the structural phase transition of V_{2}O_{3}. In both the low and high symmetry phases unique coherent phonon modes are generated at low fluence. However, coherence is lost when driving between the low and high symmetry phases. Our results suggest strongly damped noninertial dynamics dominate during the phase transition due to disorder and multimode coupling.

Barriers to adequate analgesia in paediatric burns patients.

BACKGROUND: All children with burn injuries experience pain at some time during their management and recovery. Burn pain is challenging to manage, owing to a combination of factors. The process of achieving adequate analgesia involves the correct scripting of medication based on the doctor's knowledge, the correct fulfilling of that script, and patient compliance. OBJECTIVES: To assess two components of this process, correct scripting of medication based on the doctor's knowledge and the correct filling of that script, to highlight potential barriers to adequate analgesia for burn-injured patients being followed up at an outpatient department. Patient compliance was out of the scope of this study. METHODS: The study was conducted in the Pietermaritzburg Burn Service (PBS) in Pietermaritzburg, South Africa, and was undertaken in two parts. The first part was conducted through an anonymous, voluntary questionnaire completed by doctors working in hospitals referring to the PBS. The aim of the questionnaire was to identify deficits in knowledge of doctors regarding background analgesia for burn-injured children. The second part was conducted through an audit of the outpatient folders of children attending the PBS outpatient clinic to identify discrepancies between analgesia prescribed and analgesia supplied to the patient. RESULTS: Thirty-six doctors completed the questionnaire. While nearly all the doctors prescribed background analgesia, just over half (58%) prescribed paracetamol, and of those, only half prescribed the correct dose. Half of the doctors prescribed tilidine, and only half of them knew the correct dose. Forty-seven percent of the doctors prescribed both paracetamol and tilidine for background analgesia. The outpatient folders of 59 children attending the outpatient clinic were audited. Fifty-three patients were prescribed paracetamol. There was a statistically significant difference between the paracetamol volume prescribed and the volume supplied (p<0.0001). Twenty-four patients were prescribed ibuprofen. There was a statistically significant difference between the ibuprofen volume prescribed and the volume supplied (p<0.0001). CONCLUSIONS: Burn-injured children commonly receive inadequate analgesia in our setting. The reasons for this are multifactorial. The correct dose and the correct drugs for burn-related background pain are deficits in the knowledge of doctors who deal with this common problem. Furthermore, even if the correct drug and dose are prescribed, the correct volume of medication is often not issued by the pharmacy. This study highlights barriers to achieving adequate analgesia in children with burns being managed as outpatients. Potential strategies to overcome barriers include improving education with regard to pain management and burns at an undergraduate and postgraduate level, and improved supply chain management.

A Global Geomorphologic Map of Saturn's Moon Titan.

Titan has an active methane-based hydrologic cycle1 that has shaped a complex geologic landscape2, making its surface one of most geologically diverse in the solar system. Despite the different materials, temperatures, and gravity fields between Earth and Titan, many surface features are similar between the two worlds and can be interpreted as products of the same geologic processes3. However, Titan's thick and hazy atmosphere has hindered the identification of geologic features at visible wavelengths and the study of surface composition4. Here we identify and map the major geologic units on Titan's surface using radar and infrared data from the Cassini orbiter spacecraft. Correlations between datasets enabled us to produce a global map even where data sets were incomplete. The spatial and superposition relations between major geologic units reveals the likely temporal evolution of the landscape and gives insight into the interacting processes driving its evolution. We extract the relative dating of the various geological units by observing their spatial superposition in order to get information on the temporal evolution of the landscape. Dunes and lakes are relatively young, while hummocky/mountainous terrains are the oldest on Titan. Our results also show that Titan's surface is dominated by sedimentary/depositional processes with significant latitudinal variation, with dunes at the equator, plains at mid-latitudes and labyrinth terrains and lakes at the poles.

Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers.

The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Å-1 and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure.

Metabolic status is associated with the recovery of milk somatic cell count and milk secretion after lipopolysaccharide-induced mastitis in dairy cows.

Infections of the mammary gland in dairy cows are commonly accompanied by reduced milk production and feed intake and poor milk quality. The metabolic status of early-lactating cows is known to affect immune response to pathogens and imposed immune challenges. We investigated the extent to which metabolic status before an intramammary lipopolysaccharide (LPS) challenge (LPS-CH) is associated with immune response, milk production, and feed intake and the recovery thereof. In 15 Holstein cows, weekly blood sampling and daily recording of dry matter intake, milk yield, milk composition, and body weight (to calculate energy balance) was started immediately after parturition. In wk 4 after parturition, cows underwent an intramammary LPS-CH (50 µg of LPS into 1 quarter). Blood and milk samples were taken in parallel at 30- and 60-min intervals, respectively, until 10 h after the LPS application. Plasma concentrations of glucose, nonesterified fatty acids, ß-hydroxybutyrate (BHB), cortisol, and insulin were analyzed. In milk, serum albumin, IgG concentration, somatic cell count (SCC), and lactate dehydrogenase (LDH) activity were determined. Dry matter intake and milk yield were recorded for an additional 6 d. Milk of the LPS-treated quarter was sampled at every milking for 8 d after the challenge. Based on plasma glucose concentrations in wk 1 to 4 after parturition before the LPS-CH, cows were retrospectively grouped into a high-glucose group (HG; 3.34-3.93 mmol/L, n = 7) and a low-glucose group (LG; 2.87-3.31 mmol/L, n = 8). Data were evaluated using mixed models with time, group, and time × group interaction as fixed effects and cow as repeated subject. Glucose was lower and BHB was higher in LG compared with HG before LPS-CH, whereas dry matter intake, energy balance, and SCC did not differ. During LPS-CH, SCC and LDH increased similarly in HG and LG, body temperature increased less in HG, and BHB and nonesterified fatty acids were higher in LG compared with HG. Dry matter intake declined in both groups during the day of the LPS-CH but recovered to prechallenge values faster in HG. Milk yield recovered within 2 d after the LPS-CH with no differences in morning milkings, whereas evening milk yield increased faster in HG. During 8 d after LPS-CH, SCC, LDH, IgG, and serum albumin in milk were lower in HG compared with LG. In conclusion, the level of circulating glucose and BHB concentrations in cows was associated with metabolic responses during an LPS-CH as well as the recovery of udder health and performance thereafter.

A comparison of analgesia requirements in children with burns: Do delayed referrals require higher procedural analgesia doses?

Background: Our clinical impression is that delayed referrals require more analgesia than children referred to our service acutely. Previous work demonstrated poor uptake of analgesia protocols at district hospitals with probable inadequate background and procedural analgesia, which may account for this. The purpose of this study was to compare analgesia requirements for dressing changes of paediatric patients referred to us acutely versus those children with delayed referral (i.e. more than 21 days post injury). Our hypothesis is that paediatric patients with delayed referral require higher doses of ketamine when taking length of stay and total body surface area (TBSA) of the burn into account. Methods: Data for children under 12 years, admitted to the Pietermaritzburg Burn Service (PBS) from the 1 July 2017 until 30 June 2018 was reviewed. Total ketamine dose during admission, weight, days admitted and TBSA were analysed. The total ketamine use in milligram per kilogram per days admitted per TBSA (mg/kg/days admitted/TBSA) was calculated. Statistical analysis was performed to compare the total ketamine dose between the acute and delayed referral groups. Results: One-hundred-and-ninety-seven patients were included. Patients were divided into two groups, the acute group including those referred to the PBS early (prior to 21 days post-burn) and the delayed referral group (those referred 21 days or more post burn). The acute group consisted of 167 patients and the chronic group 30 patients. There is a statistically significant difference between the total ketamine dose (mg/kg/days admitted/TBSA) for the acute referral and delayed referral groups (p = 0.01). The median total ketamine dose (mg/kg/days admitted/TBSA) of the acute referral group was 0.27 (Range: 0-7.05) and the median total Ketamine dose (mg/kg/days admitted/TBSA) for the delayed referral group was 0.41 (range: 0.1-3.89). Conclusion: Patients with delayed referrals require more ketamine to achieve adequate procedural analgesia than patients referred acutely. Inadequate analgesia in the acute phase of the burn may influence this, underpinning the importance of adequate analgesia right from the time of the injury.

The ketamine crisis: Does South Africa have a plan B?

South Africa (SA) has a high incidence of deaths from trauma and injuries. Trauma has been identified as one part of the quadruple burden of disease afflicting the country. This article is concerned with the management of burns, which 3% of the population suffer from annually. Ketamine, acknowledged for its versatility and safety profile, remains a critical component in the medical arsenal of anaesthesiologists and clinicians treating both acute and chronic pain. In the management of burn-injured patients in particular, ketamine is the cornerstone of many analgesia protocols. However, issues pertaining to shortages of this medicine in SA warrant concern and discussion, particularly in view of the high reliance of doctors on ketamine for first-line procedural analgesia in the management of burns in both adult and paediatric patients. This article attempts to highlight the issues related to ketamine shortages, which often have significant clinical, safety, operational and research implications.

Analgesia protocols for burns dressings: Challenges with implementation.

BACKGROUND: The aim of this study is to compare doctors' knowledge regarding analgesia in paediatric burns patients in a setting where analgesia protocols are provided but not reinforced to a setting where the same protocols are used but with constant re-enforcement from burns surgeons. METHODS: We reviewed questionnaires completed anonymously by doctors managing burns children in the Pietermaritzburg (PMB) Hospital Complex and the referral hospitals. RESULTS: The questionnaire was completed by 43 doctors with 53% of the participants working in the referral hospitals. Procedural sedation was given by 98% of doctors. All PMB doctors giving procedural sedation used ketamine compared to 39% in the referral hospitals, which was statistically significant (×2 = 18.237; p < 0.001). Eighty percent of PMB doctors were aware of the correct doses of ketamine and compared to 8% of referral doctors. This was statistically significant (×2 = 21.778; p < 0.001). When assessing the adequacy of analgesia, all of the doctors from PMB used a scoring system or clinical impression. In the referral doctor group, 54% used a scoring system, 38% used the child screaming as an indicator of inadequate analgesia. CONCLUSION: We have identified a discrepancy in knowledge between staff in an academic burn centre and those in peripheral referral hospitals. This discrepancy translates into differences in quality of burn analgesia which patients receive. Ongoing efforts must be directed towards changing the culture of district institution and strengthening attempts to standardize care across the region.

Ultrafast dynamics of spin and orbital correlations in quantum materials: an energy- and momentum-resolved perspective.

Many remarkable properties of quantum materials emerge from states with intricate coupling between the charge, spin and orbital degrees of freedom. Ultrafast photo-excitation of these materials holds great promise for understanding and controlling the properties of these states. Here, we introduce time-resolved resonant inelastic X-ray scattering (tr-RIXS) as a means of measuring the charge, spin and orbital excitations out of equilibrium. These excitations encode the correlations and interactions that determine the detailed properties of the states generated. After outlining the basic principles and instrumentations of tr-RIXS, we review our first observations of transient antiferromagnetic correlations in quasi two dimensions in a photo-excited Mott insulator and present possible future routes of this fast-developing technique. The increasing number of X-ray free electron laser facilities not only enables tackling long-standing fundamental scientific problems, but also promises to unleash novel inelastic X-ray scattering spectroscopies. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.

Sensitivity of stress and strain calculations to passive material parameters in cardiac mechanical models using unloaded geometries.

Cardiac stress (load) and strain (stretch) are widely studied indicators of cardiac function and outcome, but are difficult or impossible to directly measure in relation to the cardiac microstructure. An alternative approach is to estimate these states using computer methods and image-based measurements, but this still requires knowledge of the tissue material properties and the unloaded state, both of which are difficult to determine. In this work, we tested the sensitivity of these two interdependent unknowns (reference geometry and material parameters) on stress and strain calculations in cardiac tissue. Our study used a finite element model of the human ventricle, with a hyperelastic passive material model, and was driven by a cell model mediated active contraction. We evaluated 21 different published parameter sets for the five parameters of the passive material model, and for each set we optimised the corresponding unloaded geometry and contractility parameter to model a single pressure-volume loop. The resulting mechanics were compared, and calculated systolic stresses were largely insensitive to the chosen parameter set when an unloading algorithm was used. Meanwhile, material strain calculations varied substantially depending on the choice of material parameters. These results indicate that determining the correct material and unloaded configuration may be highly important to understand strain driven processes, but less so for calculating stress estimates.

Short communication: Mammary gland tight junction permeability after parturition is greater in dairy cows with elevated circulating serotonin concentrations.

After parturition, the start of copious milk production in dairy cows requires the closure of tight junctions (TJ) to form the blood-milk barrier and prevent paracellular transfer of blood constituents into milk [e.g., lactate dehydrogenase (LDH) and serum albumin (SA)] and vice versa [e.g., appearance of α-lactalbumin (α-LA) in blood]. Serotonin (5-HT) has been demonstrated to alter tight junction permeability in the mammary gland. The present study investigated individual differences of TJ permeability of mammary epithelium at the beginning of lactation in relation to circulating 5-HT in dairy cows. Blood and milk samples were obtained from 11 multiparous Holstein dairy cows for the first time at 4 h after parturition, at the following 5 milkings, and at the evening milkings on d 5, 8, 10, and 14 of lactation. Retrospectively, cows were split into 2 groups according to their calculated areas under the curve of serum 5-HT during the entire experimental period: a high-serum 5-HT (HSS) group (5 cows) and a low-serum 5-HT (LSS) group (6 cows). The areas under the curve of serum 5-HT concentrations over the 324-h experimental period were 62 ± 2 × 103 ng/mL in HSS and 25 ± 5 × 103 ng/mL in LSS. Plasma α-LA concentration was greater in LSS than in HSS cows at the first milking, but no difference between groups was found from the second to sixth milking. Yield of α-LA in milk was lower in HSS than in LSS during the first 6 milkings postpartum, especially in colostrum. Concentrations of α-LA, IgG1, and IgG2 in milk did not differ between groups during the entire experiment except for higher IgG observed in LSS than in HSS at the second milking and for higher IgG2 found in HSS compared with LSS on d 5. In contrast, SA concentrations and LDH activity in milk were lower in LSS compared with HSS cows during the first 6 milkings postpartum, particularly in colostrum. Milk somatic cell count was higher in HSS than in LSS throughout the study. Higher circulating 5-HT concentrations were associated with an increased transfer of the paracellularly transported SA, LDH, and somatic cell count, especially at the first milking, suggesting that 5-HT affects TJ permeability during closure of the blood-milk barrier at the onset of lactation. Furthermore, higher serum 5-HT concentrations were associated with a lower α-LA yield in milk. A consistent relationship with serum 5-HT concentrations was neither observed for the transfer of IgG2 nor the primarily transcellular transport of IgG1 during the first milkings after parturition.

Short communication: Circulating serotonin is related to the metabolic status and lactational performance at the onset of lactation in dairy cows.

Serotonin (5-hydroxytryptamine, 5-HT) affects many physiological functions because it is involved in glucose and lipid metabolism, calcium homeostasis, and regulation of lactation in dairy cows. This study aimed to examine physiological differences in serum 5-HT concentrations (high vs. low) and their association with metabolic status and milk production at the onset of lactation. Twelve multiparous Holstein dairy cows were milked within 4 h of calving, and blood and milk samples were collected at the first 6 subsequent milkings after parturition and at the evening milkings on d 5, 8, 10, and 14. Cows were retrospectively divided into 2 groups (6 cows/group): low serum 5-HT (LSS) and high serum 5-HT (HSS) according to their calculated areas under the curve (AUC) for serum 5-HT for the entire experimental period (cut-off: 46,000 ng/mL × 324 h). Concentrations of 5-HT, free fatty acids (FFA), ß-hydroxybutyrate (BHB), glucose, calcium, and IGF-1 were measured in blood. Milk was analyzed for fat, protein, lactose, and 5-HT concentrations. Milk yield was recorded at each milking and energy-corrected milk yield was calculated. Serum 5-HT concentrations were higher in HSS than in LSS [AUC (ng/mL × 324 h): 57,830 ± 4,810 vs. 25,005 ± 5,930]. The amount of energy-corrected milk was lower in HSS than in LSS. The HSS group produced less colostrum and had decreased milk yield, specifically during the first 6 milkings. Concentrations of FFA, BHB, and glucose in plasma did not differ between groups. Concentrations of IGF-1 in serum were elevated in HSS compared with LSS throughout the experiment. Total circulating calcium concentrations in serum tended to be higher in HSS than in LSS. Milk fat and protein yields were decreased in HSS compared with LSS. Milk 5-HT decreased overall during the experimental period, with LSS maintaining higher 5-HT concentrations than HSS until d 14 of lactation. In conclusion, cows with high serum 5-HT concentrations showed a reduced metabolic load at the onset of lactation, concomitantly lower milk yield, and a reduced energy output via milk.