Transformation of pancreatic nonfunctioning neuroendocrine tumor into metastatic insulinoma: A rare case report

Pancreatic neuroendocrine tumors can be classified as functional or nonfunctional based on hormone secretion. Management of each entity is different, with nonfunctional tumors being treated with traditional chemotherapy while functional tumors respond well to antihormonal therapy and immunologic agents. The conversion of one nonfunctional tumor into a functional tumor is an exceedingly rare event that complicates the overall management of these patients. In this report, we present the case of a 73-year-old woman who developed the conversion from a nonfunctional into a functional tumor and discuss the management options considered.

Common Noninfectious Complications Following Lung Transplantation

According to the Scientific Registry of Transplant Recipients, both transplant volume and survival among lung transplant recipients are improving over time. However, the outcomes of lung transplantation remain challenged by multiple thoracic and extrathoracic complications. With improving lung transplant survival, patients experience prolonged exposure to chronic immunosuppressive agents that can lead to multiple infectious and noninfectious complications. This article focuses on most common noninfectious complications with significant clinical impact.

Tribological Behavior of Bioinspired Surfaces

Energy losses due to various tribological phenomena pose a significant challenge to sustainable development. These energy losses also contribute toward increased emissions of greenhouse gases. Various attempts have been made to reduce energy consumption through the use of various surface engineering solutions. The bioinspired surfaces can provide a sustainable solution to address these tribological challenges by minimizing friction and wear. The current study majorly focuses on the recent advancements in the tribological behavior of bioinspired surfaces and bio-inspired materials. The miniaturization of technological devices has increased the need to understand micro- and nano-scale tribological behavior, which could significantly reduce energy wastage and material degradation. Integrating advanced research methods is crucial in developing new aspects of structures and characteristics of biological materials. Depending upon the interaction of the species with the surrounding, the present study is divided into segments depicting the tribological behavior of the biological surfaces inspired by animals and plants. The mimicking of bio-inspired surfaces resulted in significant noise, friction, and drag reduction, promoting the development of anti-wear and anti-adhesion surfaces. Along with the reduction in friction through the bioinspired surface, a few studies providing evidence for the enhancement in the frictional properties were also depicted.

Advancements in the Additive Manufacturing of Magnesium and Aluminum Alloys through Laser-Based Approach

Complex structures can now be manufactured easily utilizing AM technologies to meet the pre-requisite objectives such as reduced part numbers, greater functionality, and lightweight, among others. Polymers, metals, and ceramics are the few materials that can be used in AM technology, but metallic materials (Magnesium and Aluminum) are attracting more attention from the research and industrial point of view. Understanding the role processing parameters of laser-based additive manufacturing is critical to maximize the usage of material in forming the product geometry. LPBF (Laser powder-based fusion) method is regarded as a potent and effective additive manufacturing technique for creating intricate 3D forms/parts with high levels of precision and reproducibility together with acceptable metallurgical characteristics. While dealing with LBPF, some degree of porosity is acceptable because it is unavoidable; hot ripping and cracking must be avoided, though. The necessary manufacturing of pre-alloyed powder and ductility remains to be the primary concern while dealing with a laser-based additive manufacturing approach. The presence of the Al-Si eutectic phase in AlSi10Mg and AlSi12 alloy attributing to excellent castability and low shrinkage, attaining the most attention in the laser-based approach. Related studies with these alloys along with precipitation hardening and heat treatment processing were discussed. The Pure Mg, Mg-Al alloy, Mg-RE alloy, and Mg-Zn alloy along with the mechanical characteristics, electrochemical durability, and biocompatibility of Mg-based material have been elaborated in the work-study. The review article also summarizes the processing parameters of the additive manufacturing powder-based approach relating to different Mg-based alloys. For future aspects, the optimization of processing parameters, composition of the alloy, and quality of powder material used will significantly improve the ductility of additively manufactured Mg alloy by the LPBF approach. Other than that, the recycling of Mg-alloy powder hasn't been investigated yet. Meanwhile, the post-processing approach, including a homogeneous coating on the porous scaffolds, will mark the suitability in terms of future advancements in Mg and Al-based alloys.

Nonallograft Complications of Lung Transplantation

Long-term exposure to immunosuppressive therapy may exacerbate pre-existing medical comorbidities or result in the development of new chronic medical conditions after lung transplantation. This article focuses on common nonallograft complications with the highest impact on short- and long-term outcomes after transplantation. These include diabetes mellitus, hypertension, dyslipidemia, kidney disease (acute and chronic), and malignancy. We discuss evidence-based strategies for the prevention, diagnosis, and management of these nonallograft complications in this article.

Malakoplakia Presenting as a Lung Mass in a Lung Transplant Recipient: Case Report

Lung nodules or masses due to a variety of malignant or benign conditions such as opportunistic infections are observed after lung transplant. Malakoplakia is a rare complication in immunocompromised patients. Here we describe the clinical course and management of a lung transplant recipient with pulmonary malakoplakia and provide a review of the literature. To our knowledge, this is the first report of a case of pulmonary malakoplakia due to Escherichia coli infection in a lung allograft.

Geographic disparities in lung transplantation in the United States before and after the November 2017 allocation change

BACKGROUND

The primary lung allocation unit was expanded from the donation service area to a 250-mile radius in 2017. Prior to the change, geographic disparities in donor lung availability impacted waitlist outcomes. We sought to determine if the new allocation system improved these disparities.

METHODS

We conducted a retrospective cohort study comparing the 2-year period before and after the change. Donor lung availability was defined as the ratio of donor lungs to waitlist candidates in the primary allocation unit. Transplant centers were divided into quartiles by donor lung availability. Multivariable competing risk models were used to determine the association between lung availability and waitlist outcomes. Multivariable Cox proportional hazards models compared post-transplant survival.

RESULTS

Prior to the allocation change, the unadjusted transplant rate at centers in the lowest and highest quartiles was 132 and 607 transplants per 100 waitlist years. Candidates in the lowest quartile of donor lung availability had a 61% adjusted lower transplantation rate compared to candidates in highest quartile (sub-hazard ratio [sHR]: 0.39, 95% confidence interval [CI]: 0.34-0.44). After the allocation change, the disparity decreased resulting in an unadjusted transplant rate of 141 and 309 among centers in the lowest and highest quartiles. Candidates in the lowest quartile had a 38% adjusted lower transplantation rate compared to those in the highest (sHR: 0.62, 95% CI: 0.57-0.68). There was no significant difference in 1-year post-transplant survival.

CONCLUSIONS

Although the expansion of the primary allocation unit improved disparities in waitlist outcomes without any change in post-transplant survival, there still remain significant differences due to geography.

Early postoperative complications in lung transplant recipients

Lung transplantation has become an established therapy for end-stage lung diseases. Early postoperative complications can impact immediate, mid-term, and long-term outcomes. Appropriate management, prevention, and early detection of these early postoperative complications can improve the overall transplant course. In this review, we highlight the incidence, detection, and management of these early postoperative complications in lung transplant recipients.

Evaluation of a personal protective equipment support programme for staff during the COVID-19 pandemic in London

BACKGROUND

The coronavirus disease 2019 pandemic has presented an enormous challenge to healthcare providers worldwide. The appropriate use of personal protective equipment (PPE) has been essential to ensure staff and patient safety. The 'PPE Helper Programme' was developed at a large London hospital group to counteract suboptimal PPE practice. Based on a behaviour change model of capability, opportunity and motivation (COM-B), the programme provided PPE support, advice and education to ward staff.

AIM

Evaluation of the PPE Helper Programme.

METHODS

Clinical and non-clinical ward staff completed a questionnaire informed by the Theoretical Domains Framework and COM-B model. The questionnaire was available in paper and electronic versions. Quantitative responses were analysed using descriptive and non-parametric statistics, and free-text responses were analysed thematically.

FINDINGS

Over a 6-week period, PPE helpers made 268 ward visits. Overall, 261 questionnaires were available for analysis. Across the Trust, 68% of respondents reported having had contact with a PPE helper. Staff who had encountered a PPE helper responded significantly more positively to a range of statements about using PPE than staff who had not encountered a PPE helper. Black and minority ethnic staff were significantly more anxious regarding the adequacy of PPE. Non-clinical and redeployed staff (e.g. domestic staff) were most positive about the impact of PPE helpers. Free-text comments showed that staff found the PPE Helper Programme supportive and would have liked it earlier in the pandemic.

CONCLUSION

The PPE Helper Programme is a feasible and beneficial intervention for providing support, advice and education to ward staff during infectious disease outbreaks.

Enhanced durability, bio-activity and corrosion resistance of stainless steel through severe surface deformation

Owing to its good biocompatibility and low cost, stainless steel is one of the most widely utilized biomaterial. However, longtime assessment of stainless steel has shown problems related to material degradation, especially localized corrosion and bio-film formation. In addition, the leaching of toxic nickel and chromium ions from stainless steel leads to additional health complications. Here, we utilized submerged friction stir processing, a severe surface deformation technique for significantly enhancing its durability, bio-activity as well as antibacterial resistance. The processing was done with a wide variation in strain rates to produce tunable surface microstructure. High strain-rate processing resulted in nearly single-phase fine-grained microstructure, while slow strain-rate processing developed a dual-phase fine-grained microstructure. The bio-corrosion rate of processed steel was reduced by more than 60 % along with significant enhancement in the pitting resistance. The processed steel showed nearly no bacterial adhesion/biofilm formation, evaluated using S. aureus and E. coli bacterial strains. Further, the processed stainless steel surface demonstrated minimum leaching of the toxic elements, significantly enhancing its appeal for bio-implant applications. The observed behavior was explained based on the formation of a stable passive layer, rich in Cr₂O₃, as determined using x-ray photoelectron microscopy (XPS) and increased hydrophilicity.

Enhanced Biocorrosion Resistance and Cellular Response of a Dual-Phase High Entropy Alloy through Reduced Elemental Heterogeneity

The leaching out of toxic elements from metallic bioimplants has serious repercussions, including allergies, peripheral neuritis, cancer, and Alzheimer's disease, leading to revision or replacement surgeries. The development of advanced structural materials with excellent biocompatibility and superior corrosion resistance in the physiological environment holds great significance. High entropy alloys (HEAs) with a huge compositional design space and outstanding mechanical and functional properties can be promising for bioimplant applications. However, microstructural heterogeneity arising from elemental segregation in these multiprinciple alloy systems is the Achilles heel in the development of next-generation HEAs. Here, we demonstrate a pathway to homogenize the microstructure of a biocompatible dual-phase HEA, comprising refractory elements, namely, MoNbTaTiZr, through severe surface deformation using stationary friction processing (SFP). The strain and temperature field during processing homogenized the elemental distribution, which was otherwise unresponsive to conventional annealing treatments. Nearly 15 min of the SFP treatment resulted in a significant elemental homogenization across dendritic and interdendritic regions, similar to a week-long annealing treatment at 1275 K. The SFP processed alloy showed a nearly six times higher biocorrosion resistance compared to its as-cast counterpart. X-ray photoelectron spectroscopy was used to investigate the nature of the oxide layer formed on the specimens. Superior corrosion behavior of the processed alloy was attributed to the formation of a stable passive layer with zirconium oxide as the primary constituent and higher hydrophobicity. Biocompatibility studies performed using the human mesenchymal stem cell line, showed higher viability for the processed HEA compared to its as-cast counterpart as well as conventional metallic biomaterials including stainless steel (SS316L) and titanium alloy (Ti6Al4V).

Does the obesity paradox predict functional outcome in intracerebral hemorrhage?

OBJECTIVEBeing overweight or mildly obese has been associated with a decreased risk of death or hospitalization in patients with cardiovascular disease. Similarly, overweight patients admitted to an intensive care unit (ICU) have improved survival up to 1 year after admission. These counterintuitive observations are examples of the "obesity paradox." Does the obesity paradox exist in patients with intracerebral hemorrhage (ICH)? In this study the authors examined whether there was an association between obesity and functional outcome in patients with ICH.METHODSThe authors analyzed 202 patients admitted to the neurological ICU (NICU) who were prospectively enrolled in the Columbia University ICH Outcomes Project between September 2009 and December 2012. Patients were categorized into 2 groups: overweight (body mass index [BMI] ≥ 25 kg/m2) and not overweight (BMI < 25 kg/m2). The primary outcome was defined as survival with favorable outcome (modified Rankin Scale [mRS] score 0-3) versus death or severe disability (mRS score 4-6) at 3 months.RESULTSThe mean age of the patients in the study was 61 years. The mean BMI was 28 ± 6 kg/m2. The mean Glasgow Coma Scale score was 10 ± 4 and the mean ICH score was 1.9 ± 1.3. The overall 90-day mortality rate was 41%. Among patients with a BMI < 25 kg/m2, 24% (17/70) had a good outcome, compared with 39% (52/132) among those with a BMI ≥ 25 kg/m2 (p = 0.03). After adjusting for ICH score, sex, do-not-resuscitate code status, and history of hypertension, being overweight or obese (BMI ≥ 25 kg/m2) was associated with twice the odds of having a good outcome compared with patients with BMI < 25 kg/m2 (adjusted odds ratio 2.05, 95% confidence interval 1.03-4.06, p = 0.04).CONCLUSIONSIn patients with ICH admitted to the NICU, being overweight or obese (BMI ≥ 25 kg/m2) was associated with favorable outcome after adjustment for established predictors. The reason for this finding requires further study.

High Tensile Ductility and Strength in Dual-phase Bimodal Steel through Stationary Friction Stir Processing

The combination of high strength and good ductility are very desirable for advanced structural and functional applications. However, measures to enhance strength typically lead to ductility reduction due to their inverse correlation, nano-grained structures for an instance. Bi-modal grain structure is promising in this regard, but its realization is limited by multiple complex processing steps. Here, we demonstrate a facile single-step processing route for the development of bimodal grain structure in austenitic stainless steel, SS316L. The bimodal structure comprised of fine martensite grains (<500 nm) sandwiched between coarse austenite grains (~10 µm). The dual-phase bimodal structure demonstrated higher yield strength (~620 MPa) compared to ultra-fine grain structure (~450 MPa) concurrent with high uniform tensile ductility (~35%). These exceptional properties are attributed to unique dual-phase, bimodal grain structure which delayed the onset of plastic instability resulting in higher strength as well as larger uniform elongation and work-hardening rate. Our approach may be easily extended to a wide range of material systems to engineer superior performance.

Microwave synthesized complex concentrated alloy coatings: Plausible solution to cavitation induced erosion-corrosion

Surface phenomenon such as cavitation erosion-corrosion limits the working life and durability of the fluid machines through significantly altering the efficiency. Surface modification is an apparent and economical route for improving the sustainability of these components. Recently developed complex concentrated alloys (CCAs) or high entropy alloys (HEAs) possess exceptional properties owing to high configurational entropy. We developed CCA coatings on the stainless steel using a facial and effective microwave processing technique. The effect of Al molar fraction in Al_xCoCrFeNi (x = 0.1-3) CCAs on ultrasonic cavitation erosion-corrosion was investigated in 3.5% NaCl solution. For comparison, cavitation erosion and electrochemical corrosion behavior of the pre- and post-tested samples was also performed. Detailed microstructure and mechanical characterization of the developed coatings were also preformed using different analytical techniques. The equimolar CCA coating showed apical degradation resistance under both pure erosion and erosion-corrosion conditions. The observed behavior is attributed to high strain hardening, optimal hardness, fracture toughness, and utmost stability of the passive layer. The phenomenal conjugation of these properties was associated with highest configurational entropy for equimolar composition resulting in sluggish diffusion, and severe lattice straining. Compared to pits, striations and cracks characterizing the morphology of the degraded stainless steel, the equimolar and Al_0.1CoCrFeNi CCAs showed TTS (tearing topograph surface) as the dominant failure mode characterized by presence of microplastic deformation. The degradation of the Al₃CoCrFeNi CCA occurred mainly through brittle failure mode. The difference in failure mechanism is related to the mechanical properties and underlying microstructure.

Treatment of Tracheobronchial Injuries: A Contemporary Review

Tracheobronchial injury is a rare but a potentially high-impact event with significant morbidity and mortality. Common etiologies include blunt or penetrating trauma and iatrogenic injury that might occur during surgery, endotracheal intubation, or bronchoscopy. Early recognition of clinical signs and symptoms can help risk-stratify patients and guide management. In recent years, there has been a paradigm shift in the management of tracheal injury towards minimally invasive modalities, such as endobronchial stent placement. Although there are still some definitive indications for surgery, selected patients who meet traditional surgical criteria as well as those patients who were deemed to be poor surgical candidates can now be managed successfully using minimally invasive techniques. This paradigm shift from surgical to nonsurgical management is promising and should be considered prior to making final management decisions.

Ultrasonic cavitation erosion-corrosion behavior of friction stir processed stainless steel

Cavitation erosion remains the primary cause of material degradation in fluid machinery components operating at high speed. Micro-jets/shock waves caused by implosion of bubbles on material surface results in significant material loss and premature failure of the components. The presence of corrosive medium further exuberates this effect, causing rapid degradation. Here, we demonstrate a novel pathway to control cavitation erosion-corrosion by tailoring the surface properties using submerged friction stir processing (FSP), a severe plastic deformation process. FSP parameters were varied over wide range of strain-rates to generate tailored microstructures. High strain-rate processing resulted in nearly single phase fine grained structure while low strain-rate processing resulted in phase transformation in addition to grain refinement. As-received and processed samples were subjected to ultrasonic cavitation in distilled water as well as in corrosive environment of 3.5% NaCl solution. Individual roles of cavitation erosion, corrosion and their synergistic effects were analyzed. Depending on the microstructure, processed samples showed nearly 4-6 times higher cavitation erosion resistance compared to as-received alloy. Superior cavitation erosion-corrosion resistance of processed samples was attributed to surface strengthening, higher strain-hardening ability and quick passivation kinetics. The results of current study could be potentially transformative in designing robust materials for hydro-dynamic applications.

Post-transplant lymphoproliferative disorder of the bladder in a lung transplant recipient

Post-transplant lymphoproliferative disorder (PTLD) occurs in ~5% of solid organ and hematopoietic stem cell transplant recipients. We report a unique presentation of PTLD in the bladder of a lung transplant recipient. Our patient was a 62-year-old female who received a bilateral lung transplant for chronic obstructive pulmonary disease. She presented with fever, left-sided flank pain and foul-smelling urine consistent with urosepsis. An abdominal and pelvic computerized tomography revealed an irregular and nodular bladder wall thickening suspicious for urothelial neoplasm. Cystoscopy revealed multiple bladder masses and biopsy demonstrated non-Hodgkin lymphoma consistent with PTLD. She was treated with a reduction in immunosuppression followed by chemotherapy and achieved remission. PTLD in the lung transplant recipients has been described in the gut, respiratory tract, skin, liver and kidney but not in the bladder. This case highlights the need for maintaining a high clinical vigilance even when transplant recipients present with seemingly benign clinical complaints.

Exceptionally high cavitation erosion and corrosion resistance of a high entropy alloy

Cavitation erosion and corrosion of structural materials are serious concerns for marine and offshore industries. Durability and performance of marine components are severely impaired due to degradation from erosion and corrosion. Utilization of advanced structural materials can play a vital role in limiting such degradation. High entropy alloys (HEAs) are a relatively new class of advanced structural materials with exceptional properties. In the present work, we report on the cavitation erosion behavior of Al_0.1CoCrFeNi HEA in two different media: distilled water with and without 3.5wt% NaCl. For comparison, conventionally used stainless steel SS316L was also evaluated in identical test conditions. Despite lower hardness and yield strength, the HEA showed significantly longer incubation period and lower erosion-corrosion rate (nearly 1/4th) compared to SS316L steel. Enhanced erosion resistance of HEA was attributed to its high work-hardening behavior and stable passivation film on the surface. The Al_0.1CoCrFeNi HEA showed lower corrosion current density, high pitting resistance and protection potential compared to SS316L steel. Further, HEA showed no evidence of intergranular corrosion likely due to the absence of secondary precipitates. Although, the degradation mechanisms (formation of pits and fatigue cracks) were similar for both the materials, the damage severity was found to be much higher for SS316L steel compared to HEA.

Friction Stir Processing of Stainless Steel for Ascertaining Its Superlative Performance in Bioimplant Applications

Substrate-cell interactions for a bioimplant are driven by substrate's surface characteristics. In addition, the performance of an implant and resistance to degradation are primarily governed by its surface properties. A bioimplant typically degrades by wear and corrosion in the physiological environment, resulting in metallosis. Surface engineering strategies for limiting degradation of implants and enhancing their performance may reduce or eliminate the need for implant removal surgeries and the associated cost. In the current study, we tailored the surface properties of stainless steel using submerged friction stir processing (FSP), a severe plastic deformation technique. FSP resulted in significant microstructural refinement from 22 μm grain size for the as-received alloy to 0.8 μm grain size for the processed sample with increase in hardness by nearly 1.5 times. The wear and corrosion behavior of the processed alloy was evaluated in simulated body fluid. The processed sample demonstrated remarkable improvement in both wear and corrosion resistance, which is explained by surface strengthening and formation of a highly stable passive layer. The methylthiazol tetrazolium assay demonstrated that the processed sample is better in supporting cell attachment, proliferation with minimal toxicity, and hemolysis. The athrombogenic characteristic of the as-received and processed samples was evaluated by fibrinogen adsorption and platelet adhesion via the enzyme-linked immunosorbent assay and lactate dehydrogenase assay, respectively. The processed sample showed less platelet and fibrinogen adhesion compared with the as-received alloy, signifying its high thromboresistance. The current study suggests friction stir processing to be a versatile toolbox for enhancing the performance and reliability of currently used bioimplant materials.

Nanotribological and wetting performance of hierarchical patterns

Surface modification is a promising method to solve the tribological problems in microsystems. To modify the surface, we fabricated hierarchical patterns with different pitches of nano-scale features and different surface chemistries. Micro- and nano-patterns with similar geometrical configurations were also fabricated for comparison. The nano-tribological behavior of the patterns was investigated using an atomic force microscope at different relative humidity levels (5% to 80%) and applied normal loads (40 nN to 120 nN) under a constant sliding velocity. The results showed significant enhancement in the de-wetting and tribological performance of the hierarchical patterns compared with those of flat and micro- and nano-patterned surfaces. The PTFE-coated hierarchical patterns showed similar dynamic contact angles (advancing and receding) to those of the real lotus leaf. The influence of relative humidity on adhesion and friction behavior was found to be significant for all the tested surfaces. The tribological performance was improved as the pitch of the nano-scale geometry of the hierarchical pattern increased, even though the wetting property was not influenced significantly. A model was proposed based on the role of intermolecular force to explain the effect of the pitch of the hierarchical patterns on the adhesion and friction behavior. According to the model based on the molecular force, the contact between a ball and the patterned surface was a multi-asperity contact, contrary to the single-asperity contact predicted by the Johnson-Kendall-Roberts (JKR) and Maugis-Dugdale (MD) models. The strong intermolecular forces, which are activated in the confined spaces between the adjacent nano-pillars and the ball, contributed to the contact area and hence the adhesion and friction forces.

Role of Viscous Dissipative Processes on the Wetting of Textured Surfaces

We investigate the role of viscous forces on the wetting of hydrophobic, semi-hydrophobic, and hydrophilic textured surfaces as second-order effects. We show that during the initial contact, the transition from inertia- to viscous-dominant regime occurs regardless of their surface topography and chemistry. Furthermore, we demonstrate the effect of viscosity on the apparent contact angle under quasi-static conditions by modulating the ratio of a water/glycerol mixture and show the effect of viscosity, especially on the semi-hydrophobic and hydrophobic textured substrates. The reason why the viscous force does not affect the apparent contact angle of the hydrophilic surface is explained based on the relationship between the disjoining pressure and surface chemistry. We further propose a wetting model that can predict the apparent contact angle of a liquid drop on a textured substrate by incorporating a viscous force component in the force balance equation. This model can predict apparent contact angles on semi-hydrophobic and hydrophobic textured surfaces exhibiting Wenzel state more accurately than the Wenzel model, indicating the importance of viscous forces in determining the apparent contact angle. The modified model can be applied for estimating the wetting properties of arbitrary engineered surfaces.

The role of bio-inspired hierarchical structures in wetting

Superhydrophobicity facilitates the development of self-cleaning, anti-biofouling, and anti-corrosion surfaces. The leaves of the lotus (Nelumbo nucifera) and taro (Colocasia esculenta) plants are well known for their self-cleaning properties. A hierarchical structure comprising papillae epidermal cells superimposed with epicuticular wax crystalloids of varying shapes, sizes, and orientations is an important aspect of the surface of these plant leaves. We fabricated two types of hierarchical structures biomimicking the surface topography of the lotus leaf. The hierarchical patterns successfully demonstrated the superhydrophobic state in comparison with nano and micro patterns. We used the finite element method (FEM) to simulate and understand the wetting process. The FEM simulations showed good correlation with the experimental results. FEM was helpful in understanding the wetting of enormously complex biological surfaces with relative ease, and it qualifies as a potential tool for designing superhydrophobic surfaces. Using the FEM framework, we further designed surfaces to optimize the order of the shapes in hierarchy. The results showed that the superhydrophobic surface with the lowest wetted area was obtained by placing shapes with smaller geometric angles at the top of the hierarchy. This arrangement of shapes provides the optimum combination of superhydrophobicity and surface integrity. This observation explains why the hierarchical structure of many superhydrophobic leaves follows this order. We also investigated the complex hierarchical structure of Salvinia minima. Owing to its remarkable ability to entrap air and pin the contact line, it exhibits superhydrophobicity along with the much-required Cassie state. These properties of Salvinia minima make it an excellent candidate for developing omniphobic surfaces.

Effect of topography on the wetting of nanoscale patterns: experimental and modeling studies

We investigated the influence of nanoscale pattern shapes, contours, and surface chemistry on wetting behavior using a combination of experimental and modeling approaches. Among the investigated topographical shapes, re-entrant geometries showed superior performance owing to their ability to restrain the liquid-air interface in accordance with Gibbs criteria. The wetting state is also controlled by the surface texture in addition to the surface chemistry. Topographies with smaller intrinsic angles are better able to support the liquid droplet. Based on these observations, two geometrical relationships for designing superhydrophobic patterns exhibiting the Cassie-Baxter state are proposed. A detailed analysis of the simulation results showed the presence of viscous forces during the initial transient phase of the droplet interaction with the solid surface even at negligible normal velocity, which was verified experimentally using a high-speed imaging technique. During this transient phase, for a polystyrene surface, the liquid front was observed to be moving with a radial velocity of 0.4 m s(-1), which gradually decreased to almost zero after 35 ms. We observed that the viscous energy dissipation density is influenced by the surface material and topography and the wetting state. The viscous energy dissipation density is minimal in the case of the Cassie-Baxter state, while it becomes quite significant for the Wenzel state. The viscous effects are reduced for topographies with smooth geometries and surfaces with high slip length.

Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing

We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 μm to 5 μm) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites.

A tumor that is not a tumor but it sure can kill!

Background:

Pott’s puffy tumor is a life threatening complication of infectious sinusitis which is the osteomyelitis of the frontal bone with associated subperiosteal abscess causing swelling and edema over the forehead and scalp.

Case Report:

Here we present a case a 38 year old male with a rare infectious complication of untreated or inadequately treated sinusitis called Pott’s puffy tumor which was diagnosed due to high clinical suspicion and confirmed with CT imaging and biopsy.

Conclusions:

This case highlights the need to recognize and easily prevent this fatal complication of a seemingly benign infection like bacterial sinusitis. Unfortunately, if it does occur, clinicians can avoid missing the diagnosis by upholding a high clinical suspicion in the setting of known risk factors and must look for underlying causes both medical and psychosocial.

Serial dobutamine stress echocardiography with Doppler assessment of the left internal thoracic artery graft after minimally invasive bypass for a patient with an orthotopic heart transplant

Select patients who have undergone orthotopic heart transplantation with proximal left anterior disease may be candidates for minimally invasive direct coronary artery bypass surgery. Combining left internal thoracic artery transthoracic Doppler flow assessment with wall motion assessment during dobutamine stress echocardiography adds to the utility of this test by focusing attention on the graft's status as well as detecting ischemia due to cardiac allograft vasculopathy.

Bone grafting for spinal fusion

At least 250,000 spinal fusions are performed in the United States each year, nearly all requiring implantation of bone graft material. The preferred technique for most of these operations is the transplantation of structured or morcellized autologous corticocancellous bone from the iliac crest. Further, because of the increasing frequency of spinal fusion surgery during the 1990s, arthrodesis of the spine has become the most common reason for autologous bone graft harvest. This article reviews the current clinical status of autogenous bone grafts and alternative materials in spinal fusion surgery.

Fungal production of citric acid

Citric acid is the principal organic acid found in citrus fruits. To meet increasing demands it is produced from carbohydrate feedstock by fermentation with the fungus Aspergillus niger and the yeasts of Candida spp. Effect of various fermentation conditions and the biochemistry of citric acid formation by A. niger have been discussed. Commercially citric acid is produced by surface, submerged and solid state fermentation techniques. Recovery of pure acid from fermentation broth is done primarily by precipitation with lime and also by solvent extraction.

Susceptibility of two crossbreeds of sheep to Haemonchus contortus

Studies were conducted on 20 crossbred lambs of 4-5 months old. Ten lambs were Nali x Corriedale cross (Hisardale) and the other 10 were Nali x Lohi cross (Munjal). Seven lambs each of both crossbreeds were infected with 10,000 infective larvae of Haemonchus contortus. Three lambs of each crossbreed served as uninfected controls. Clinicopathological examinations were done before and after infection and all the lambs were necropsied 28 days post-infection. The body weight gain, haemoglobin and packed cell volume were significantly lower in Hisardale lambs and the peripheral eosinophil count was significantly higher in Munjal lambs. Significant hypoalbuminaemia and hypoglobulinaemia, a sharp increase in albumin: globulin ratio; significantly higher faecal egg counts; adult worm counts; abomasal pH, volume, congestion and oedema were observed in Hisardale lambs as compared to Munjal lambs. Clinical signs of haemonchosis were more severe in Hisardale lambs and two of them died. Munjal lambs therefore seem less susceptible than Hisardale lambs to H. contortus infection.