Anomalous magnetoresistance and magneto-thermal properties of the half-Heuslers,RPdSi (RY, Gd-Er)

Here, we present a detailed study on the magnetic, magneto-transport, and magneto-thermal properties of the equiatomic half-Heusler compounds with the general formula,RPdSi (R= Y and rare-earth, Gd-Er). These materials crystallize in two different superstructures of the TiNiSi-type orthorhombic unit cell with the space groupsPnmaandPmmn. Our magnetic and heat capacity measurements reveal the onset of an antiferromagnetic (AFM) ordering in the temperature range 3-16 K for all the local moments bearingRPdSi compounds, while the non-magnetic analog, YPdSi exhibits a Pauli-paramagnetic behaviour. The AFM state of these compounds can be tuned by magnetic field and temperature as demonstrated by the magnetic measurements below the Neel temperature (T_N). Most importantly, this tuning of the magnetic structure is well documented in the complex temperature and field dependence of magnetoresistance (MR) and magnetocaloric effect (MCE). Our study establishes a striking correlation of the commensurate/incommensurate AFM structure with that of positive/negative MR and MCE in this series of compounds. We emphasize that such a framework applies to a large number of AFM intermetallic systems.

Use of regional analgesia and risk of delirium in older adults with multiple rib fractures: An Eastern Association for the Surgery of Trauma multicenter study

BACKGROUND

Single-center data demonstrates that regional analgesia (RA) techniques are associated with reduced risk of delirium in older patients with multiple rib fractures. We hypothesized that a similar effect between RA and delirium would be identified in a larger cohort of patients from multiple level I trauma centers.

METHODS

Retrospective data from seven level I trauma centers were collected for intensive care unit (ICU) patients 65 years or older with ≥3 rib fractures from January 2012 to December 2016. Those with a head and/or spine injury Abbreviated Injury Scale (AIS) score of ≥ 3 or a history of dementia were excluded. Delirium was defined as one positive Confusion Assessment Method for the Intensive Care Unit score in the first 7 days of ICU care. Poisson regression with robust standard errors was used to determine the association of RA (thoracic epidural or paravertebral catheter) with delirium incidence.

RESULTS

Data of 574 patients with a median age of 75 years (interquartile range [IQR], 69-83), Injury Severity Score of 14 (IQR, 11-18), and ICU length of stay of 3 days (IQR, 2-6 days) were analyzed. Among the patients, 38.9% were women, 15.3% were non-White, and 31.4% required a chest tube. Regional analgesia was used in 19.3% patients. Patient characteristics did not differ by RA use; however, patients with RA had more severe chest injury (chest AIS, flail segment, hemopneumothorax, thoracostomy tube). In univariate analysis, there was no difference in the likelihood of delirium between the RA and no RA groups (18.9% vs. 23.8% p = 0.28). After adjusting for age, sex, Injury Severity Score, maximum chest AIS, thoracostomy tube, ICU length of stay, and trauma center, RA was associated with reduced risk of delirium (incident rate ratio [IRR], 0.65; 95% confidence interval [CI], 0.44-0.94) but not with in-hospital mortality (IRR, 0.42; 95% CI, 0.14-1.26) or respiratory complications (IRR, 0.70; 95% CI, 0.42-1.16).

CONCLUSION

In this multicenter cohort of injured older adults with multiple rib fractures, RA use was associated with a 35% lower risk of delirium. Further studies are needed to standardize protocols for optimal pain management and prevention of delirium in older adults with severe thoracic injury.

LEVEL OF EVIDENCE

Therapeutic, level IV; Epidemiologic, level III.

Outcomes after ultramassive transfusion in the modern era: An Eastern Association for the Surgery of Trauma multicenter study

BACKGROUND

Despite the widespread institution of modern massive transfusion protocols with balanced blood product ratios, survival for patients with traumatic hemorrhage receiving ultramassive transfusion (UMT) (defined as ≥20 U of packed red blood cells [RBCs]) in 24 hours) remains low and resource consumption remains high. Therefore, we aimed to identify factors associated with mortality in trauma patients receiving UMT in the modern resuscitation era.

METHODS

An Eastern Association for the Surgery of Trauma multicenter retrospective study of 461 trauma patients from 17 trauma centers who received ≥20 U of RBCs in 24 hours was performed (2014-2019). Multivariable logistic regression and Classification and Regression Tree analysis were used to identify clinical characteristics associated with mortality.

RESULTS

The 461 patients were young (median age, 35 years), male (82%), severely injured (median Injury Severity Score, 33), in shock (median shock index, 1.2; base excess, -9), and transfused a median of 29 U of RBCs, 22 U of fresh frozen plasma (FFP), and 24 U of platelets (PLT). Mortality was 46% at 24 hours and 65% at discharge. Transfusion of RBC/FFP ≥1.5:1 or RBC/PLT ≥1.5:1 was significantly associated with mortality, most pronounced for the 18% of patients who received both RBC/PLT and RBC/FFP ≥1.5:1 (odds ratios, 3.11 and 2.81 for mortality at 24 hours and discharge; both p < 0.01). Classification and Regression Tree identified that age older than 50 years, low initial Glasgow Coma Scale, thrombocytopenia, and resuscitative thoracotomy were associated with low likelihood of survival (14-26%), while absence of these factors was associated with the highest survival (71%).

CONCLUSION

Despite modern massive transfusion protocols, one half of trauma patients receiving UMT are transfused with either RBC/FFP or RBC/PLT in unbalanced ratios ≥1.5:1, with increased associated mortality. Maintaining focus on balanced ratios during UMT is critical, and consideration of advanced age, poor initial mental status, thrombocytopenia, and resuscitative thoracotomy can aid in prognostication.

LEVEL OF EVIDENCE

Prognostic, level III.

Trauma and nontrauma damage-control laparotomy: The difference is delirium (data from the Eastern Association for the Surgery of Trauma SLEEP-TIME multicenter trial)

BACKGROUND

Damage-control laparotomy (DCL) has been used for traumatic and nontraumatic indications. We studied factors associated with delirium and outcome in this population.

METHODS

We reviewed DCL patients at 15 centers for 2 years, including demographics, Charlson Comorbidity Index (CCI), diagnosis, operations, and outcomes. We compared 30-day mortality; renal failure requiring dialysis; number of takebacks; hospital, ventilator, and intensive care unit (ICU) days; and delirium-free and coma-free proportion of the first 30 ICU days (DF/CF-ICU-30) between trauma (T) and nontrauma (NT) patients. We performed linear regression for DF/CF-ICU-30, including age, sex, CCI, achievement of primary fascial closure (PFC), small and large bowel resection, bowel discontinuity, abdominal vascular procedures, and trauma as covariates. We performed one-way analysis of variance for DF/CF-ICU-30 against traumatic brain injury severity as measured by Abbreviated Injury Scale for the head.

RESULTS

Among 554 DCL patients (25.8% NT), NT patients were older (58.9 ± 15.8 vs. 39.7 ± 17.0 years, p < 0.001), more female (45.5% vs. 22.1%, p < 0.001), and had higher CCI (4.7 ± 3.3 vs. 1.1 ± 2.2, p < 0.001). The number of takebacks (1.7 ± 2.6 vs. 1.5 ± 1.2), time to first takeback (32.0 hours), duration of bowel discontinuity (47.0 hours), and time to PFC were similar (63.2 hours, achieved in 73.5%). Nontrauma and T patients had similar ventilator, ICU, and hospital days and mortality (31.0% NT, 29.8% T). Nontrauma patients had higher rates of renal failure requiring dialysis (36.6% vs. 14.1%, p < 0.001) and postoperative abdominal sepsis (40.1% vs. 17.1%, p < 0.001). Trauma and NT patients had similar number of hours of sedative (89.9 vs. 65.5 hours, p = 0.064) and opioid infusions (106.9 vs. 96.7 hours, p = 0.514), but T had lower DF/CF-ICU-30 (51.1% vs. 73.7%, p = 0.029), indicating more delirium. Linear regression analysis indicated that T was associated with a 32.1% decrease (95% CI, 14.6%-49.5%; p < 0.001) in DF/CF-ICU-30, while achieving PFC was associated with a 25.1% increase (95% CI, 10.2%-40.1%; p = 0.001) in DF/CFICU-30. Increasing Abbreviated Injury Scale for the head was associated with decreased DF/CF-ICU-30 by analysis of variance (p < 0.001).

CONCLUSION

Nontrauma patients had higher incidence of postoperative abdominal sepsis and need for dialysis, while T was independently associated with increased delirium, perhaps because of traumatic brain injury.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Amelogenin Peptide-Chitosan Hydrogel for Biomimetic Enamel Regrowth

We designed synthetic peptides that have demonstrated an effective remineralization potential to restore incipient enamel decay. In order to develop a clinically viable approach we incorporated the amelogenin-derived peptides P26 and P32 into chitosan hydrogel and examined their efficacy in the remineralization of enamel. Peptides in chitosan exhibited increased stability in vitro as compared to peptides in solution at room temperature and at 37°C. Tooth models for enamel erosion (sections) and white spot lesions (blocks) were subject to periods of demineralization. Treatment groups were subjected to remineralization in artificial saliva in the presence of P26 and P32 in solution and in chitosan hydrogel (P26-CS and P32-CS). Quantitative light-induced fluorescence (QLF) was employed to analyze mineral density following demineralization and remineralization across all the treatment groups. Scanning electron microscopy and nanoindentation were used to characterize the surface structure and mechanical strength of regrown enamel. Control enamel sections treated in artificial saliva demonstrated randomly distributed, tiny, needle-shaped crystals with a low packing density and porosities displaying mineralization defects. In samples treated with P26-CS or P32-CS a denser coating of organized hydroxyapatite (HAP) crystals was formed covering the entire surfaces of demineralized enamel window. The hardness and modulus of enamel surfaces were increased after treatment with P26-CS and P32-CS with no significant difference in the mechanical properties between the two peptide hydrogels. Analysis of mineral density by QLF showed that in enamel sections P26 peptide alone or P26-CS significantly enhanced the remineralization. In enamel blocks P26 in solution had a better efficacy than P26-CS.

Structure driven magnetic correlations and magnetodielectric coupling in 6H-perovskite Ba3DyRu2O9

The 6H-perovskites Ba₃(R/M)Ru₂O₉(R= rare Earth,M= transition metal) exhibit complex magnetism and have been extensively studied recently for their magnetodielectric (MD) properties. Here, we present a detailed study of structural, magnetic, thermodynamic and MD properties of a 6H-perovskite Ba₃DyRu₂O₉. This compound is found to undergo long range antiferromagnetic ordering below ∼5.8 K (T_N), along with the presence of metamagnetic transition at low temperatures. The heat capacity shows two additional anomalies at ∼28 K (T₁) and ∼33 K (T₂), besides the anomaly atT_N. Signature of these anomalies is also visible in the derivative of magnetization curve. The dielectric response also shows weak anomalies aroundT₁andT₂at zero field whereas anomaly atT₂gets suppressed at 80 kOe. The observed MD coupling of ∼2%-4% at 80 kOe field below ∼30 K temperature range, is among the highest values observed for the compounds of this family. Low temperature crystal structures of the compound show sharp distortion of Ru₂O₉octahedra nearT₂. Our study points toward the emergence of structurally driven spin correlations of Ru moments resulting in the observed MD coupling in this compound.

Lumbar and sacral brucellosis due to queso fresco ingestion

Brucellosis is rare in the USA, with 100–200 cases reported annually. In this case we illustrate the complex management of spinal brucellosis. A 22-year-old male presented with 3 months of low back pain. Imaging revealed osteomyelitis/diskitis of L5/S1 and abscesses involving the pre-vertebral, epidural and pelvic recesses. Initial biopsies were inconclusive, but the patient later endorsed eating unpasteurized cheese (queso fresco) from Mexico; therefore, Brucella serology was sent and was positive. Despite aggressive antibiotic therapy there was disease progression. The patient underwent debridement of the involved vertebrae and drainage. Multiple cultures failed to grow the organisms, but Brucella polymerase chain reaction was positive. A month later he underwent a second vertebral debridement as well as placement of tobramycin impregnated beads in the vertebral space. He has since recovered. Surgery should be considered if there is a poor response to medical management and patients may need repeated debridement.

Clinical and Radiographic Factors Associated With Failed Renal Angioembolization: Results From the Multi-institutional Genitourinary Trauma Study (Mi-GUTS)

OBJECTIVE

To find clinical or radiographic factors that are associated with angioembolization failure after high-grade renal trauma.

MATERIAL AND METHODS

Patients were selected from the Multi-institutional Genito-Urinary Trauma Study. Included were patients who initially received renal angioembolization after high-grade renal trauma (AAST grades III-V). This cohort was dichotomized into successful or failed angioembolization. Angioembolization was considered a failure if angioembolization was followed by repeat angiography and/or an exploratory laparotomy.

RESULTS

A total of 67 patients underwent management initially with angioembolization, with failure in 18 (27%) patients. Those with failed angioembolization had a larger proportion ofgrade IV (72% vs 53%) and grade V (22% vs 12%) renal injuries. A total of 53 patients underwent renal angioembolization and had initial radiographic data for review, with failure in 13 cases. The failed renal angioembolization group had larger perirenal hematoma sizes on the initial trauma scan.

CONCLUSION

Angioembolization after high-grade renal trauma failed in 27% of patients. Failed angioembolization was associated with higher injury grade and a larger perirenal hematoma. Likely these characteristics are associated with high-grade renal trauma that may be less amenable to successful treatment after a single renal angioembolization.

Impact of Robotic Surgery on Residency Training for Herniorrhaphy and Cholecystectomy

Robotic surgery has increased for common general surgery procedures. This study evaluates how robotic use affects the case distributions of herniorrhaphy and cholecystectomy for general surgery residents according to postgraduate year (PGY). We reviewed Accreditation Council for Graduate Medical Education (ACGME) biliary or hernia cases logged by surgical residents in the academic year 2017-2018. Operative reports were reviewed to compare approaches (robotic, laparoscopic, and open) by resident role and PGY level. Open cholecystectomies were excluded. Overall, 470 hernia and 657 cholecystectomy cases were logged. Hernia repairs were performed robotically in 15.9%, laparoscopically in 9.5%, and open in 74.7%. Cholecystectomies were performed robotically in 16.4% and laparoscopically in 83.6%. Residents were teaching assistants in 1.8% of hernia repairs and 1.5% of cholecystectomies. Distribution of cases by technique and PGY level was significantly different for both procedures, with chief residents performing the majority of robotic cholecystectomies (52.6%, P < .0001) and hernia repairs (59.7%, P < .0001). Migration of robotic cases to senior resident level and low percentage of teaching assistant roles held by residents suggest exposure to common operations may be delayed during general surgery residency training. Introduction of new technology in surgical training should be carefully reviewed and may benefit from a structured curriculum.

Bootstrapping M-estimators in generalized autoregressive conditional heteroscedastic models

We consider the weighted bootstrap approximation to the distribution of a class of M-estimators for the parameters of the generalized autoregressive conditional heteroscedastic model. We prove that the bootstrap distribution, given the data, is a consistent estimate in probability of the distribution of the M-estimator, which is asymptotically normal. We propose an algorithm for the computation of M-estimates which at the same time is useful for computing bootstrap replicates from the given data. Our simulation study indicates superior coverage rates for various weighted bootstrap schemes compared with the rates based on the normal approximation and existing bootstrap methods for the generalized autoregressive conditional heteroscedastic model, such as percentile $t$-subsampling schemes. Since some familiar bootstrap schemes are special cases of the weighted bootstrap, this paper thus provides a unified theory and algorithm for bootstrapping in generalized autoregressive conditional heteroscedastic models.

Allyl piperidine-1-carbodiothioate and benzyl 1H-imidazole 1 carbodithioate: two potential agents to combat against mycobacteria

AIMS

The emergence of multidrug resistant strains of Mycobacterium tuberculosis has made tuberculosis more difficult to manage clinically. With the aim of obtaining new and effective anti-mycobacterial agent(s), this study investigated the anti-mycobacterial activity of several imidazole and piperidine derivatives.

METHODS AND RESULTS

Towards obtaining new anti-mycobacterial agents, Mycobacterium smegmatis cells were treated with different compounds for their growth inhibitory activity. Among these, benzyl 1H-imidazole-1-carbodithioate and allyl piperidine-1-carbodiothioate exhibited better inhibition than the others. Thereafter, anti-biofilm property of these two was examined by treating M. smegmatis with these agents before and after the formation of biofilm. The result showed that both the compounds at their sublethal dose inhibited the formation of biofilm as well as dispersed preformed biofilm. Consistently, they augmented the activity of isoniazid or rifampicin against biofilm-encapsulated cells. MTT assay was performed to examine the toxic effects of this combinatorial therapy on different cell lines. Results exhibited a low cytotoxicity for this combinatorial treatment. The activity of these two was also verified against dormant mycobacterial cells and was found to be effective.

CONCLUSION

The present study identified two compounds that exhibited anti-mycobacterial activities against both planktonic and dormant cells. These two also exhibited anti-biofilm activity at their sublethal dose and augmented the activity of isoniazid and rifampicin against biofilm encapsulated cells.

SIGNIFICANCE AND IMPACT OF THE STUDY

The current study provides two new agents that have the potential to be used in anti-mycobacterial therapy and may help in public health management.

Haploinsufficiency of X-linked intellectual disability gene CASK induces post-transcriptional changes in synaptic and cellular metabolic pathways

Heterozygous mutations in the X-linked gene CASK are associated with intellectual disability, microcephaly, pontocerebellar hypoplasia, optic nerve hypoplasia and partially penetrant seizures in girls. The Cask^+/- heterozygous knockout female mouse phenocopies the human disorder and exhibits postnatal microencephaly, cerebellar hypoplasia and optic nerve hypoplasia. It is not known if Cask^+/- mice also display seizures, nor is known the molecular mechanism by which CASK haploinsufficiency produces the numerous documented phenotypes. 24-h video electroencephalography demonstrates that despite sporadic seizure activity, the overall electrographic patterns remain unaltered in Cask^+/- mice. Additionally, seizure threshold to the commonly used kindling agent, pentylenetetrazol, remains unaltered in Cask^+/- mice, indicating that even in mice the seizure phenotype is only partially penetrant and may have an indirect mechanism. RNA sequencing experiments on Cask^+/- mouse brain uncovers a very limited number of changes, with most differences arising in the transcripts of extracellular matrix proteins and the transcripts of a group of nuclear proteins. In contrast to limited changes at the transcript level, quantitative whole-brain proteomics using iTRAQ quantitative mass-spectrometry reveals major changes in synaptic, metabolic/mitochondrial, cytoskeletal, and protein metabolic pathways. Unbiased protein-protein interaction mapping using affinity chromatography demonstrates that CASK may form complexes with proteins belonging to the same functional groups in which altered protein levels are observed. We discuss the mechanism of the observed changes in the context of known molecular function/s of CASK. Overall, our data indicate that the phenotypic spectrum of female Cask^+/- mice includes sporadic seizures and thus closely parallels that of CASK haploinsufficient girls; the Cask^+/- mouse is thus a face-validated model for CASK-related pathologies. We therefore surmise that CASK haploinsufficiency is likely to affect brain structure and function due to dysregulation of several cellular pathways including synaptic signaling and cellular metabolism.

Enhancing Collagen Mineralization with Amelogenin Peptide: Towards the Restoration of Dentin

Mammalian teeth primarily consist of two distinct calcified tissues, enamel and dentin, that are intricately integrated by a complex and critical structure, the dentin-enamel junction (DEJ). Loss of enamel exposes the underlying dentin, increasing the risk of several irreversible dental diseases. This paper highlights the significance of utilizing the functional domains of a major enamel matrix protein, amelogenin, intrinsic to tooth enamel and the DEJ interface, to rationally design smaller bioinspired peptides for regeneration of tooth microstructures. Using this strategy, we designed a synthetic peptide, P26, that demonstrates a remarkable dual mineralization potential to restore incipient enamel decay and mineralization defects localized in peripheral dentin below the DEJ. As a proof of principle, we demonstrate that interaction between P26 and collagen prompts peptide self-assembly, followed by mineralization of collagen fibrils in vitro. P26-mediated nucleation of hydroxyapatite (HAP) crystals on demineralized dentin in situ significantly facilitates the recovery of mineral density and effectively restores the biomechanical properties of dentin to near-native levels, suggesting that P26-based therapy has promising applications for treating diverse mineralized tissue defects in the tooth.

Load transfer across a mandible during a mastication cycle: The effects of odontogenic tumour

The extent to which load transfer in a diseased mandible with odontogenic tumour might influence the potential risk of pathological fracture has scarcely been investigated. The study sought to investigate the quantitative deviations in load transfer across healthy and cancer-affected (diseased) mandibles having odontogenic tumours. The effect of size of the tumours (small: 9 mm diameter, large: 19 mm diameter), and variation in bone mechanical (elastic) properties of the mandible on load transfer in cancer-affected mandibles during a mastication cycle have been investigated. Based on patient-specific computed tomography-scan datasets, detailed three-dimensional finite element models of healthy and diseased mandibles were developed. High stresses of 25-30 MPa and strains ∼700 µε were observed in the healthy mandible during the right molar bite. However, marginal deviations were observed in principal stress distributions in the diseased mandibles with small- and large-sized tumours, as compared to the healthy mandible. Maximum principal strains of ∼1474 µε were found in the body region adjacent to the symphysis region for small-sized tumour. Whereas for large-sized tumour, maximum strains of ∼2700 µε were observed in the right buccal regions. Reduction in Young's modulus due to different stages of odontogenic tumours had a localised effect on the principal stress distributions, but triggered an abrupt increase in the principal tensile strains. It appears that there is a potential risk of pathological fracture for large-sized odontogenic tumour, owing to high tensile stresses and strains.

Possibility of a new order parameter driven by multipolar moment and Fermi surface evolution in CeGe

Polycrystalline CeGe is investigated by means of DC and AC susceptibility, non-linear DC susceptibility, electrical transport and heat capacity measurements in the low temperature regime. This compound shows two peaks at low magnetic field around T^I ~ 10.7 and T^II ~ 7.3 K due to antiferromagnetic ordering and subsequent spin rearrangement respectively. Investigation of non-linear DC susceptibility reveals a presence of higher order magnetization which results in the development of a new order parameter around T^I. This leads to a lowering of symmetry of the magnetic state. The order parameter increases with decreasing temperature and stabilizes around T^II. Consequently, the symmetry of the magnetic state is preserved below this transition. Heat capacity and resistivity results indicate the presence of a gap opening around T^I on portion of Fermi surface, due to evolution of the Fermi surface. Magnetoresistance behavior and violation of Kohler’s rule suggest that the evolution of Fermi surface changes the symmetry of magnetic state. The observation of new order parameter (which is of second order) is also confirmed from the Landau free energy theory.

A comparative assessment of two designs of hip stem using rule-based simulation of combined osseointegration and remodelling

The stem–bone interface of cementless total hip arthroplasty undergoes an adaptive process of bone ingrowth until the two parts become osseointegrated. Another important phenomenon associated with aseptic loosening of hip stem is stress-shielding induced adverse bone remodelling. The objective of this study was to preclinically assess the relative performances of two distinct designs of hip stems by addressing the combined effect of bone remodelling and osseointegration, based on certain rule-based criteria obtained from the literature. Premised upon non-linear finite element analyses of patient-specific implanted femur models, the study attempts to ascertain in silico outcome of the hip stem designs based on an evolutionary interfacial condition, and to further comment on the efficacy of the rule-based technique on the prediction of peri-prosthetic osseointegration. One of the two hip stem models was a trade-off design obtained from an earlier shape optimization study, and the other was based on TriLock stem (DePuy). Both designs predicted similar long-term osseointegration (∼89% surface), although trade-off stem predicted higher post-operative osseointegration. Proximal bone resorption was found higher for TriLock (by ∼110%) as compared to trade-off model. The rule-based technique predicted clinically coherent osseointegration around both stems and appears to be an alternative to expensive mechanobiology-based schemes.

Assessment of healthcare measures, healthcare resource use, and cost of care among severe hemophilia A patients in Mumbai region of India

Background

In India, the low public health priority given to rare disorders such as hemophilia hinders their management and optimal care, leading to relatively poor health outcomes. This study aims to profile the multidimensional health status of patients with severe hemophilia A, and its association with the use of healthcare resources and the cost of care in Mumbai region of India.

Subjects and Methods

A cross-sectional, single-center study was conducted during January-May 2011, among 160 patients diagnosed with severe hemophilia A in Mumbai region of India. Their health status was documented using the Hemophilia Utilization Group Study's validated instrument of Functional Health Status Measure (FHS) and a single item of Self-care Measure.

Results

Of 160 patients, 55% (n = 88) scored on the lower side on the FHS, with an average score of 6.65 ± 2.85. The use of healthcare resources and cost of treatment were considerable for patients with a lower mean rank score on the FHS and a higher mean rank score on the self-care measure. The consumption of clotting factor concentrates (CFCs), number of visits to a health facility and incidence of inpatient episodes were significantly associated with a relatively low score on the FHS. Similarly, a higher cost of treatment, in terms of the cost of CFCs, direct cost, emergency room cost, and indirect cost, were significantly associated with a lower score on the FHS.

Conclusion

The health status of patients with severe hemophilia A is compromised and has a significant impact on the use of healthcare resources and the cost of treatment.

Sedation and paralytic use in open abdomen patients-results from the EAST SLEEP Survey

BACKGROUND

Patients with an open abdomen after trauma or emergency surgery may benefit from reduced sedation and chemical paralysis. We studied the effect of attending surgeon experience on sedation depth and paralytic use, as well as enteral nutrition and time between laparotomies.

METHODS

We performed an institutional review board-approved survey (Sedation Level after Emergent ExLap without Primary Fascial Closure) of the senior and active Eastern Association for the Surgery of Trauma membership using Qualtrics (Qualtrics, Inc, Provo, UT). We obtained 393/1,655 responses (23.7%). Spearman's rho was used for ordinal data, and multivariate logistic regression was used to adjust for trauma center level and presence of trainees in the relationship between surgeon experience and use of deep sedation.

RESULTS

Surgeon experience was associated with deep sedation (Richmond Agitation and Sedation Score ≤-3, P = .001) and chemical paralysis (P = .001). Surgeon experience was associated with less concern about delirium and more concern for evisceration as the reason for sedation depth (P = .001) and for paralysis (P = .001). Using multivariate logistic regression, surgeon experience was associated with deep sedation (odds ratio 3.6 [95% confidence interval 1.3, 10.4], P = .017 for ≥20 years; odds ratio 3.5 [95% confidence interval 1.1, 10.4], P = .025 for 15-20 years). Trauma center level was also significant (odds ratio 7.2 for Richmond Agitation and Sedation Score ≤-3 [95% confidence interval 1.7, 31.0], P = .008 for level III/IV versus level I/II). Increased surgeon experience was associated with delay of commencement of enteral feeds until return of bowel function (P = .013). Few respondents indicated willingness to extubate or mobilize open abdomen patients. Experienced surgeons were likely to wait for a defined time rather than for normalization of resuscitation markers to perform the first takeback laparotomy (P = .047) and waited longer between subsequent laparotomies (P = .004).

CONCLUSION

There were significant variations in practice among respondents based on the length of time since their last residency or fellowship, including variations that deviate from current best practice for management of patients with an open abdomen.

The associations between initial radiographic findings and interventions for renal hemorrhage after high-grade renal trauma: Results from the Multi-Institutional Genitourinary Trauma Study

BACKGROUND

Indications for intervention after high-grade renal trauma (HGRT) remain poorly defined. Certain radiographic findings can be used to guide the management of HGRT. We aimed to assess the associations between initial radiographic findings and interventions for hemorrhage after HGRT and to determine hematoma and laceration sizes predicting interventions.

METHODS

The Genitourinary Trauma Study is a multicenter study including HGRT patients from 14 Level I trauma centers from 2014 to 2017. Admission computed tomography scans were categorized based on multiple variables, including vascular contrast extravasation (VCE), hematoma rim distance (HRD), and size of the deepest laceration. Renal bleeding interventions included angioembolization, surgical packing, renorrhaphy, partial nephrectomy, and nephrectomy. Mixed-effect Poisson regression was used to assess the associations. Receiver operating characteristic analysis was used to define optimal cutoffs for HRD and laceration size.

RESULTS

In the 326 patients, injury mechanism was blunt in 81%. Forty-seven (14%) patients underwent 51 bleeding interventions, including 19 renal angioembolizations, 16 nephrectomies, and 16 other procedures. In univariable analysis, presence of VCE was associated with a 5.9-fold increase in risk of interventions, and each centimeter increase in HRD was associated with 30% increase in risk of bleeding interventions. An HRD of 3.5 cm or greater and renal laceration depth of 2.5 cm or greater were most predictive of interventions. In multivariable models, VCE and HRD were significantly associated with bleeding interventions.

CONCLUSION

Our findings support the importance of certain radiographic findings in prediction of bleeding interventions after HGRT. These factors can be used as adjuncts to renal injury grading to guide clinical decision making.

LEVEL OF EVIDENCE

Prognostic and Epidemiological Study, Level III and Therapeutic/Care Management, Level IV.

Design of porous titanium scaffold for complete mandibular reconstruction: The influence of pore architecture parameters

Patients having a medical history of oral cancer, infectious diseases or trauma are often advised surgical intervention with customized complete mandibular constructs (CMC) made of Titanium (Ti) scaffolds. A numerical framework based on a homogenization technique was developed to investigate the influence of pore architecture parameters on homogenized orthotropic material properties of the scaffolds. A comparative 3D Finite Element (FE) analysis of six CMC models, having homogenized orthotropic material properties, under a mastication cycle, was undertaken to pre-clinically determine the optimal CMC for a patient. Orthotropic material properties of Ti-scaffolds decreased with an increase in the inter-strut distance. Stress and strain distributions of CMC models during right molar bite were investigated. Despite small differences in stress distributions in the 'body' region of CMC models, the overall stress distribution (tensile and compressive) of CMC models (30-32 MPa) were well comparable to that of an intact mandible (34.54 MPa). Higher magnitudes of tensile strains were observed for models with 0.2 mm (9884μɛ) and 0.4 mm strut diameter (SD), both having 0.5 mm inter-strut distance (ID), at articular condyle area, body and symphysis equivalent part of the constructs. The maximum principal tensile strains were higher in the CMC models with 0.5 mm ID as compared to those having 0.3 mm ID. Comparatively, the scaffolds with lesser ID (0.3 mm) resulted in higher stiffness, thereby evoking less principal strains in the CMC models. Moreover, considering the weight of the scaffolds, the CMC models having 0.3 mm ID with 0.2 mm SD and 0.5 mm ID with 0.6 mm SD seemed most appropriate for a patient.

Control of Calcium Phosphate Nucleation and Transformation through Interactions of Enamelin and Amelogenin Exhibits the "Goldilocks Effect"

Although amelogenin comprises the vast majority of the matrix that templates calcium phosphate nucleation during enamel formation, other proteins, particularly enamelin, are also known to play an important role in the formation of enamel's intricate architecture. However, there is little understanding of the interplay between amelogenin and enamelin in controlling processes of mineral nucleation and growth. Here, we used an in vitro model to investigate the impact of enamelin interaction with amelogenin on calcium phosphate nucleation for a range of enamelin-to-amelogenin ratios. We found that amelogenin alone is a weak promoter of nucleation, but addition of enamelin enhanced nucleation rates in a highly nonlinear, nonmonotonic manner reaching a sharp maximum at a ratio of 1:50 enamelin/amelogenin. We provide a phenomenological model to explain this effect that assumes only isolated enamelin proteins can act as sites of enhanced nucleation, while enamelin oligomers cannot. Even when interaction is random, the model reproduces the observed behavior, suggesting a simple means to tightly control the timing and extent of nucleation and phase transformation by amelogenin and enamelin.

Cation-specific interactions of protein surface charges in dilute aqueous salt solutions: a combined study using dielectric relaxation spectroscopy and Raman spectroscopy

We exploited glycine as a zwitterionic model system to experimentally probe the cation specific interaction of protein surface charges in dilute (≤0.25 mol L-1) aqueous solutions of four biologically relevant inorganic salts, NaCl, KCl, MgCl2 and CaCl2, via dielectric relaxation spectroscopy (DRS) and Raman spectroscopy. Glycine is the simplest building block of proteins and it exposes the same charged groups (carboxylate and ammonium) to the solvent that dominate the protein-water interface. As a counter ion, we selected Cl- due to its biological importance. For all systems, we performed simultaneous fitting of the real (ε') and imaginary (ε″) parts of the dielectric functions, assuming a multimodal relaxation model, obtained from concentration dependent dielectric measurements at ∼293 K. We observe a reduction of the dielectric amplitude for the glycine relaxation while the corresponding time constant shows only small (<7%) deviations compared to aqueous glycine solutions. We propose that the observed reduction in dielectric amplitude is due to a reduction of the effective dipole moment (µeff) of zwitterionic glycine caused by the interaction of glycine with the ion even at very low (0.05 M) salt concentrations. The interaction between divalent metal ions and zwitterionic glycine is increased compared to the monovalent cation-zwitterion interaction; a finding that is also supported by Raman spectroscopy. Our combined dielectric relaxation and Raman spectroscopic study indicates that ion-glycine interactions are weak and mediated by the solvent. Cation-specificity of protein surface charges is also observed in dilute salt solutions (≤0.25 mol L-1), where electrostatic interactions dominate.

Suicide in the Elderly: A Multidisciplinary Approach to Prevention

Suicide in the elderly is a growing problem. The elderly population is increasing, and elderly patients have multiple issues that place them at higher risk of suicidality. These issues include physical illnesses, mental illness, loss of functional status, isolation, and family, financial, and social factors. Access to firearms is another significant risk factor, because elderly patients are more likely to use firearms in suicide attempts; interventions to reduce firearms mortality may save lives. Tackling the difficult problem of suicide in the elderly may require a multidisciplinary, community-based series of interventions.

In Vivo Molecular Toxicity Profile of Dental Bioceramics in Embryonic Zebrafish ( Danio rerio)

The investigation of the biocompatibility of potential and commercially available dental material is a major challenge in dental science. This study demonstrates that the zebrafish model is a novel in vivo model for investigating the biocompatibility of dental materials. Two commercially available dental materials, mineral trioxide aggregate (MTA) and Biodentine, were assessed for their biocompatibility. The biocompatibility analysis was performed in embryonic zebrafish with the help of standard toxicity assays measuring essential parameters such as survivability and hatching. The mechanistic and comparative analysis of toxicity was performed by oxidative stress analysis by measuring ROS induction and apoptosis in zebrafish exposed to dental materials at different concentrations. The molecular investigation at the protein level was done by a computational approach using in silico molecular docking and pathway analysis. The toxicity analysis showed a significant reduction in hatching and survivability rates along with morphological malformations with an increase in the concentration of exposed materials. ROS and apoptosis assay results revealed a greater biocompatibility of Biodentine as compared to that of MTA which was concentration-dependent. In silico analysis showed the significant role of the tricalcium silicate-protein ( Sod1, tp53, RUNX2B) interaction in an exhibition of toxicity. The study provides a new vision and standard in dental material sciences for assessing the biocompatibility of potential novel and commercially available dental materials.

Complex magnetic behaviour and evidence of a superspin glass state in the binary intermetallic compound Er5Pd2

The binary intermetallic compound Er₅Pd₂ has been investigated using dc and ac magnetic susceptibilities, magnetic memory effect, isothermal magnetization, non-linear dc susceptibility, heat capacity and magnetocaloric effect studies. Interestingly, even though the compound does not show geometrical frustration it undergoes glassy magnetic phase transition below 17.2 K. Investigation of dc magnetization and heat capacity data divulged absence of long-ranged magnetic ordering. Through the magnetic memory effect, time dependent magnetization and ac susceptibility studies it was revealed that the compound undergoes glass-like freezing below 17.2 K. Analysis of frequency dependence of this transition temperature through scaling and Arrhenius law; along with the Mydosh parameter indicate, that the dynamics in Er₅Pd₂ are due to the presence of strongly interacting superspins rather than individual spins. This phase transition was further investigated by non-linear dc susceptibility and was characterized by static critical exponents γ and δ. Our results indicate that this compound shows the signature of superspin glass at low temperature. Additionally, both conventional and inverse magnetocaloric effect was observed with a large value of magnetic entropy change and relative cooling power. Our results suggest that Er₅Pd₂ can be classified as a superspin glass system with large magnetocaloric effect.

Peptide-Based Bioinspired Approach to Regrowing Multilayered Aprismatic Enamel

The gradual discovery of functional domains in native enamel matrix proteins has enabled the design of smart bioinspired peptides for tooth enamel mimetics and repair. In this study, we expanded upon the concept of biomineralization to design smaller amelogenin-inspired peptides with conserved functional domains for clinical translation. The synthetic peptides displayed a characteristic nanostructured scaffold reminiscent of 'nanospheres' seen in the enamel matrix and effectively controlled apatite nucleation in vitro resulting in the formation of smaller crystallites. Following application of the peptides to sectioned human molar teeth, a robust, oriented, synthetic aprismatic enamel was observed after 7 days of incubation in situ. There was a two-fold increase in the hardness and modulus of the regrown enamel-like apatite layers and an increase in the attachment of the tooth-regrown layer interface compared to control samples. Repeated peptide applications generated multiple enamel-like hydroxyapatite (HAP) layers of limited thickness produced by epitaxial growth in which c-axis oriented nanorods evolved on the surface of native enamel. We conclude that peptide analogues with active domains can effectively regulate the orientation of regenerated HAP layers to influence functional response. Moreover, this enamel biofabrication approach demonstrates the peptide-mediated growth of multiple microscale HAP arrays of organized microarchitecture with potential for enamel repair.

Beta-blockers and Traumatic Brain Injury: A Systematic Review, Meta-analysis, and Eastern Association for the Surgery of Trauma Guideline

OBJECTIVE

To determine if beta-(β)-blockers improve outcomes after acute traumatic brain injury (TBI).

BACKGROUND

There have been no new inpatient pharmacologic therapies to improve TBI outcomes in a half-century. Treatment of TBI patients with β-blockers offers a potentially beneficial approach.

METHODS

Using MEDLINE, EMBASE, and CENTRAL databases, eligible articles for our systematic review and meta-analysis (PROSPERO CRD42016048547) included adult (age ≥ 16 years) blunt trauma patients admitted with TBI. The exposure of interest was β-blocker administration initiated during the hospitalization. Outcomes were mortality, functional measures, quality of life, cardiopulmonary morbidity (e.g., hypotension, bradycardia, bronchospasm, and/or congestive heart failure). Data were analyzed using a random-effects model, and represented by pooled odds ratio (OR) with 95% confidence intervals (CI) and statistical heterogeneity (I).

RESULTS

Data were extracted from 9 included studies encompassing 2005 unique TBI patients with β-blocker treatment and 6240 unique controls. Exposure to β-blockers after TBI was associated with a reduction of in-hospital mortality (pooled OR 0.39, 95% CI: 0.27-0.56; I = 65%, P < 0.00001). None of the included studies examined functional outcome or quality of life measures, and cardiopulmonary adverse events were rarely reported. No clear evidence of reporting bias was identified.

CONCLUSIONS

In adults with acute TBI, observational studies reveal a significant mortality advantage with β-blockers; however, quality of evidence is very low. We conditionally recommend the use of in-hospital β-blockers. However, we recommend further high-quality trials to answer questions about the mechanisms of action, effectiveness on subgroups, dose-response, length of therapy, functional outcome, and quality of life after β-blocker use for TBI.

Proline Precursors and Collagen Synthesis: Biochemical Challenges of Nutrient Supplementation and Wound Healing

Wound healing is a complex process marked by highly coordinated immune fluxes into an area of tissue injury; these are required for re-establishment of normal tissue integrity. Along with this cascade of cellular players, wound healing also requires coordinated flux through a number of biochemical pathways, leading to synthesis of collagen and recycling or removal of damaged tissues. The availability of nutrients, especially amino acids, is critical for wound healing, and enteral supplementation has been intensely studied as a potential mechanism to augment wound healing-either by increasing tensile strength, decreasing healing time, or both. From a practical standpoint, although enteral nutrient supplementation may seem like a reasonable strategy to augment healing, a number of biochemical and physiologic barriers exist that limit this strategy. In this critical review, the physiology of enteral amino acid metabolism and supplementation and challenges therein are discussed in the context of splanchnic physiology and biochemistry. Additionally, a review of studies examining various methods of amino acid supplementation and the associated effects on wound outcomes are discussed.

The Presence of MMP-20 Reinforces Biomimetic Enamel Regrowth

Biomimetic synthesis of artificial enamel is a promising strategy for the prevention and restoration of defective enamel. We have recently reported that a hydrogel system composed of chitosan-amelogenin (CS-AMEL) and calcium phosphate is effective in forming an enamel-like layer that has a seamless interface with natural tooth surfaces. Here, to improve the mechanical system function and to facilitate the biomimetic enamel regrowth, matrix metalloproteinase-20 (MMP-20) was introduced into the CS-AMEL hydrogel. Inspired by our recent finding that MMP-20 prevents protein occlusion inside enamel crystals, we hypothesized that addition of MMP-20 to CS-AMEL hydrogel could reinforce the newly grown layer. Recombinant human MMP-20 was added to the CS-AMEL hydrogel to cleave full-length amelogenin during the growth of enamel-like crystals on an etched enamel surface. The MMP-20 proteolysis of amelogenin was studied, and the morphology, composition, and mechanical properties of the newly grown layer were characterized. We found that amelogenin was gradually degraded by MMP-20 in the presence of chitosan. The newly grown crystals in the sample treated with MMP-20-CS-AMEL hydrogel showed more uniform orientation and greater crystallinity than the samples treated with CS-AMEL hydrogel without MMP-20. Stepwise processing of amelogenin by MMP-20 in the CS-AMEL hydrogel prevented undesirable protein occlusion within the newly formed crystals. As a result, both the modulus and hardness of the repaired enamel were significantly increased (1.8- and 2.4-fold, respectively) by the MMP-20-CS-AMEL hydrogel. Although future work is needed to further incorporate other enamel matrix proteins into the system, this study brings us one step closer to biomimetic enamel regrowth.

Combined Bone Ingrowth and Remodeling Around Uncemented Acetabular Component: A Multiscale Mechanobiology-Based Finite Element Analysis

Bone ingrowth and remodeling are two different evolutionary processes which might occur simultaneously. Both these processes are influenced by local mechanical stimulus. However, a combined study on bone ingrowth and remodeling has rarely been performed. This study is aimed at understanding the relationship between bone ingrowth and adaptation and their combined influence on fixation of the acetabular component. Based on three-dimensional (3D) macroscale finite element (FE) model of implanted pelvis and microscale FE model of implant–bone interface, a multiscale framework has been developed. The numerical prediction of peri-acetabular bone adaptation was based on a strain-energy density-based formulation. Bone ingrowth in the microscale models was simulated using the mechanoregulatory algorithm. An increase in bone strains near the acetabular rim was observed in the implanted pelvis model, whereas the central part of the acetabulum was observed to be stress shielded. Consequently, progressive bone apposition near the acetabular rim and resorption near the central region were observed. Bone remodeling caused a gradual increase in the implant–bone relative displacements. Evolutionary bone ingrowth was observed around the entire acetabular component. Poor bone ingrowth of 3–5% was predicted around the centro-inferio and inferio-posterio-superio-peripheral regions owing to higher implant–bone relative displacements, whereas the anterio-inferior and centro-superior regions exhibited improved bone ingrowth of 35–55% due to moderate implant–bone relative displacement. For an uncemented acetabular CoCrMo component, bone ingrowth had hardly any effect on bone remodeling; however, bone remodeling had considerable influence on bone ingrowth.

Flank Hernia Repair with Suture Anchor Mesh Fixation to the Iliac Crest

Traumatic or postsurgical flank hernias are complex and prone to recurrence, particularly at the border of the iliac crest. We reviewed our experience using suture anchors drilled into the iliac crest to fixate the mesh to bone. Our study of 10 repairs in eight patients was Institutional Review Board exempt. We obtained demographics, body mass index, diabetes, methicillin-resistant Staphylococcus aureus (MRSA) history, smoking status, steroid use, number of prior repairs, defect size, mesh size, number of anchors, and recurrence and infection at follow-up. We performed Kaplan-Meier analysis using a composite of recurrence or infection. Three of eight (interquartile range, 37.5%) patients were male. Median age and body mass index were 47.5 years (31.0, 54.7) and 32.2 (29.0, 36.0), respectively. Three patients had prior repairs, one each with two, three, and five prior attempts at fixation. One of eight patients (12.5%) had a history of MRSA infection. One of eight patients (12.5%) had a history of intermittent steroid use for sarcoidosis. Defect size was 90 cm2 (62.2, 165) and mesh size was 155 cm2 (150, 232) with four anchors (4, 5.5). Procedural complications included 2/10 (20%) with recurrence and 1/10 (10%) with postoperative MRSA infection. Follow-up was 12 months (3.0, 25.0). Mean freedom from recurrence and mesh infection (Kaplan-Meier) was 43.5 months (95% confidence interval = 24.2, 62.8). In conclusion, our series is one of the largest in the literature involving the suture anchor technique. Despite a high-risk patient population due to trauma, obesity, and prior smoking and MRSA history, we achieved an acceptable recurrence rate. Further study may benefit from a randomized trial design.

Flank Hernia Repair with Suture Anchor Mesh Fixation to the Iliac Crest

Traumatic or postsurgical flank hernias are complex and prone to recurrence, particularly at the border of the iliac crest. We reviewed our experience using suture anchors drilled into the iliac crest to fixate the mesh to bone. Our study of 10 repairs in eight patients was Institutional Review Board exempt. We obtained demographics, body mass index, diabetes, methicillin-resistant Staphylococcus aureus (MRSA) history, smoking status, steroid use, number of prior repairs, defect size, mesh size, number of anchors, and recurrence and infection at follow-up. We performed Kaplan-Meier analysis using a composite of recurrence or infection. Three of eight (interquartile range, 37.5%) patients were male. Median age and body mass index were 47.5 years (31.0, 54.7) and 32.2 (29.0, 36.0), respectively. Three patients had prior repairs, one each with two, three, and five prior attempts at fixation. One of eight patients (12.5%) had a history of MRSA infection. One of eight patients (12.5%) had a history of intermittent steroid use for sarcoidosis. Defect size was 90 cm2 (62.2, 165) and mesh size was 155 cm2 (150, 232) with four anchors (4, 5.5). Procedural complications included 2/10 (20%) with recurrence and 1/10 (10%) with postoperative MRSA infection. Follow-up was 12 months (3.0, 25.0). Mean freedom from recurrence and mesh infection (Kaplan-Meier) was 43.5 months (95%confidence interval = 24.2, 62.8). In conclusion, our series is one of the largest in the literature involving the suture anchor technique. Despite a high-risk patient population due to trauma, obesity, and prior smoking and MRSA history, we achieved an acceptable recurrence rate. Further study may benefit from a randomized trial design.

Influence of Implant Surface Texture Design on Peri-Acetabular Bone Ingrowth: A Mechanobiology Based Finite Element Analysis

The fixation of uncemented acetabular components largely depends on the amount of bone ingrowth, which is influenced by the design of the implant surface texture. The objective of this numerical study is to evaluate the effect of these implant texture design factors on bone ingrowth around an acetabular component. The novelty of this study lies in comparative finite element (FE) analysis of 3D microscale models of the implant-bone interface, considering patient-specific mechanical environment, host bone material property and implant-bone relative displacement, in combination with sequential mechanoregulatory algorithm and design of experiment (DOE) based statistical framework. Results indicated that the bone ingrowth process was inhibited due to an increase in interbead spacing from 200 μm to 600 μm and bead diameter from 1000 μm to 1500 μm and a reduction in bead height from 900 μm to 600 μm. Bead height, a main effect, was found to have a predominant influence on bone ingrowth. Among the interaction effects, the combination of bead height and bead diameter was found to have a pronounced influence on bone ingrowth process. A combination of low interbead spacing (P = 200 μm), low bead diameter (D = 1000 μm), and high bead height (H = 900 μm) facilitated peri-acetabular bone ingrowth and an increase in average Young's modulus of newly formed tissue layer. Hence, such a surface texture design seemed to provide improved fixation of the acetabular component.

Enhancement of magnetic ordering temperature and magnetodielectric coupling by hole doping in a multiferroic DyFe0.5Cr0.5O3

We report the results of our investigation of magnetic, thermodynamic and dielectric properties of Ca substituted half-doped orthochromite, Dy_0.6Ca_0.4Fe_0.5Cr_0.5O₃. Magnetic susceptibility and heat capacity data bring out that this compound undergoes two antiferromagnetic transitions, one at ~132 and the other at ~22 K. These values are higher than those of DyFe_0.5Cr_0.5O₃. This finding highlights that non-magnetic hole doping in form of Ca⁺² in the place of magnetic Dy⁺³ tends to enhance magnetic transition temperatures in this half-doped orthochromite. We attribute it to possible change in the valence state of Cr/Fe-ion ions due to hole doping. Dielectric anomalies are also seen near the magnetic ordering temperatures indicating magnetodielectric coupling, which is confirmed by magnetic field dependent dielectric studies. The most notable observation is that magnetodielectric coupling strength gets significantly enhanced as compared to DyFe_0.5Cr_0.5O₃. The results reveal that it is possible to tune magnetodielectric coupling by hole doping in this system.

Nutritional Aspects of Gastrointestinal Wound Healing

Significance: Although the wound healing cascade is similar in many tissues, in the gastrointestinal tract mucosal healing is critical for processes such as inflammatory bowel disease and ulcers and healing of the mucosa, submucosa, and serosal layers is needed for surgical anastomoses and for enterocutaneous fistula. Failure of wound healing can result in complications including infection, prolonged hospitalization, critical illness, organ failure, readmission, new or worsening enterocutaneous fistula, and even death. Recent Advances: Recent advances are relevant for the role of specific micronutrients, such as vitamin D, trace elements, and the interplay between molecules with pro- and antioxidant properties. Our understanding of the role of other small molecules, genes, proteins, and macronutrients is also rapidly changing. Recent work has elucidated relationships between oxidative stress, nutritional supplementation, and glucose metabolism. Thresholds have also been established to define adequate preoperative nutritional status. Critical Issues: Further work is needed to establish standards and definitions for measuring the extent of wound healing, particularly for inflammatory bowel disease and ulcers. In addition, a mounting body of evidence has determined the need for adequate preoperative nutritional supplementation for elective surgical procedures. Future Directions: A large portion of current work is restricted to model systems in rodents. Therefore, additional clinical and translational research is needed in this area to promote gastrointestinal wound healing in humans, particularly those suffering from critical illness, patients with enterocutaneous fistula, inflammatory bowel disease, and ulcers, and those undergoing surgical procedures.

Effect of rare-earth (Er and Gd) substitution on the magnetic and multiferroic properties of DyFe0.5Cr0.5O3

We report the results of our investigations on the influence of partial substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic susceptibility and heat capacity data, apart from confirming the occurrence of magnetic transitions at ~121 and 13 K in DyFe0.5Cr0.5O3, bring out that the lower transition temperature only is suppressed by rare-earth substitution. Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln  =  Er and Gd). There is an evidence for magnetoelectric coupling in all these materials with qualitative differences in its behavior as the temperature is changed across these two transitions. Remnant electric polarization is observed for all the compounds. The most notable observation is that electric polarization is seen to get enhanced as a result of rare-earth substitution with respect to that in DyFe0.5Cr0.5O3. Interestingly, a similar trend is seen in the magnetocaloric effect, consistent with the existence of magnetoelectric coupling. The results thus provide evidence for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides.

The effects of musculoskeletal loading regimes on numerical evaluations of acetabular component

The importance of clinical studies notwithstanding, the failure assessment of implant–bone structure has alternatively been carried out using finite element analysis. However, the accuracy of the finite element predicted results is dependent on the applied loading and boundary conditions. Nevertheless, most finite element–based evaluations on acetabular component used a few selective load cases instead of the eight load cases representing the entire gait cycle. These in silico evaluations often suffer from limitations regarding the use of simplified musculoskeletal loading regimes. This study attempts to analyse the influence of three different loading regimes representing a gait cycle, on numerical evaluations of acetabular component. Patient-specific computer tomography scan-based models of intact and resurfaced pelvises were used. One such loading regime consisted of the second load case that corresponded to peak hip joint reaction force. Whereas the other loading regime consisted of the second and fifth load cases, which corresponded to peak hip joint reaction force and peak muscle forces, respectively. The third loading regime included all the eight load cases. Considerable deviations in peri-acetabular strains, standard error ranging between 115 and 400 µε, were observed for different loading regimes. The predicted bone strains were lower when selective loading regimes were used. Despite minor quantitative variations in bone density changes (less than 0.15 g cm−3), the final bone density pattern after bone remodelling was found to be similar for all the loading regimes. Underestimations in implant–bone micromotions (40–50 µm) were observed for selective loading regimes after bone remodelling. However, at immediate post-operative condition, such underestimations were found to be less (less than 5 µm). The predicted results highlight the importance of inclusion of eight load cases representing the gait cycle for in silico evaluations of resurfaced pelvis.