Impact Dynamics of Non-Newtonian Droplets on Superhydrophobic Surfaces.

Droplet impact behavior on a solid surface is critical for many industrial applications such as spray coating, food production, printing, and agriculture. For all of these applications, a common challenge is to modify and control the impact regime and contact time of the droplets. This challenge becomes more critical for non-Newtonian liquids with complex rheology. In this research, we explored the impact dynamics of non-Newtonian liquids (by adding different concentrations of Xanthan into water) on superhydrophobic surfaces. Our experimental results show that by increasing the Xanthan concentration in water, the shapes of the bouncing droplet are dramatically altered, e.g., its shape at the separation moment is changed from a conventional vertical jetting into a "mushroom"-like one. As a result, the contact time of the non-Newtonian droplet could be reduced by up to ∼50%. We compare the impact scenarios of Xanthan liquids with those of glycerol solutions having a similar apparent viscosity, and results show that the differences in the elongation viscosity induce different impact dynamics of the droplets. Finally, we show that by increasing the Weber number for all of the liquids, the contact time is reduced, and the maximum spreading radius is increased.

Dynamic Mitigation Mechanisms of Rime Icing with Propagating Surface Acoustic Waves.

Ice accretion on economically valuable and strategically important surfaces poses significant challenges. Current anti-/de-icing techniques often have critical issues regarding their efficiency, convenience, long-term stability, or sustainability. As an emerging ice mitigation strategy, the thin-film surface acoustic wave (SAW) has great potentials due to its high energy efficiency and effective integration on structural surfaces. However, anti-/de-icing processes activated by SAWs involve complex interfacial evolution and phase changes, and it is crucial to understand the nature of dynamic solid-liquid-vapor phase changes and ice nucleation, growth, and melting events under SAW agitation. In this study, we systematically investigated the accretion and removal of porous rime ice from structural surfaces activated by SAWs. We found that icing and de-icing processes are strongly linked with the dynamical interfacial phase and structure changes of rime ice under SAW activation and the acousto-thermally induced localized heating that facilitate the melting of ice crystals. Subsequently, interactions of SAWs with the formed thin water layer at the ice/structure interface result in significant streaming effects that lead to further damage and melting of ice, liquid pumping, jetting, or nebulization.

Ice recrystallization inhibition activity varies with ice-binding protein type and does not correlate with thermal hysteresis.

Ice-binding proteins (IBPs) inhibit the growth of ice through surface adsorption. In some freeze-resistant fishes and insects, circulating IBPs serve as antifreeze proteins to stop ice growth by lowering the freezing point. Plants are less able to avoid freezing and some use IBPs to minimize the damage caused in the frozen state by ice recrystallization, which is the growth of large ice grains at the expense of small ones. Here we have accurately and reproducibly measured the ice recrystallization inhibition (IRI) activity of over a dozen naturally occurring IBPs from fishes, insects, plants, and microorganisms using a modified 'splat' method on serial dilutions of IBPs whose concentrations were determined by amino acid analysis. The endpoint of IRI, which was scored as the lowest protein concentration at which no recrystallization was observed, varied for the different IBPs over two orders of magnitude from 1000 nM to 5 nM. Moreover, there was no apparent correlation between their IRI levels and reported antifreeze activities. IBPs from insects and fishes had similar IRI activity, even though the insect IBPs are typically 10x more active in freezing point depression. Plant IBPs had weak antifreeze activity but were more effective at IRI. Bacterial IBPs involved in ice adhesion showed both strong freezing point depression and IRI. Two trends did emerge, including that basal plane binding IBPs correlated with stronger IRI activity and larger IBPs had higher IRI activity.

An investigation into the kinematics of magnetically driven droplets on various (super)hydrophobic surfaces and their application to an automated multi-droplet platform.

Magnetic actuation on digital microfluidic (DMF) platforms may provide a low-cost, less cumbersome alternative for droplet manipulation in comparison to other techniques such as electrowetting-on-dielectric. Precise control of droplets in magnetically driven DMF platforms is achieved using a low-friction surface, magnetically susceptible material/droplet(s), and an applied magnetic field. Superhydrophobic (SH) surfaces offer limited friction for aqueous media as defined by their high water contact angles (WCA) (>150°) and low sliding angles (<10°). The low surface friction of such coatings and materials significantly reduces the force required for droplet transport. Here, we present a study that examines several actuation parameters including the effects of particle and particle-free actuation mechanisms, porous and non-porous SH materials, surface chemistry, droplet speed/acceleration, and the presence of surface energy traps (SETs) on droplet kinematics. Automated actuation was performed using an XY linear stepper gantry, which enabled sequential droplet actuation, mixing, and undocking operations to be performed in series. The results of this study are applied to a quantitative fluorescence-based DNA assay in under 2 min. Graphical abstract ᅟ.

Burmese python target reflectivity compared to natural Florida foliage background reflectivity.

The Florida Everglades is infested with Burmese pythons caused by the release of exotic pets in the 1980s. The current estimates are between 30,000 and 300,000 pythons, where the result is a severe decline in Everglade mammals: 90% reductions in raccoon, opossum, bobcats, and foxes. The marsh rabbits are completely gone. The population of the pythons is rapidly increasing exponentially with 20-50 eggs per snake with a life span of up to 20 years. Pythons have been captured in the Everglades with lengths of nearly 6 m. Researchers in the state of Florida are concerned that these pythons are (1) permanently damaging the Everglades, (2) migrating further north into populated areas of Florida, and (3) endangering wildlife, pets, and eventually, people. There have been a number of sensing efforts attempted in the large-area detection of pythons, where limited success has been achieved. For example, infrared sensors have been applied to the problem, but the pythons are cold-blooded, so the infrared bands do not work well. Imec has leveraged its expertise and infrastructure in semiconductor processing to produce highly compact, higher performance, and relatively cheaper hyperspectral image sensors and camera systems. In this work, Imec teamed with the University of Florida and Extended Reality Systems to obtain hyperspectral reflectivity measurements of Burmese pythons along with natural Florida background foliage to determine bands or band combinations that may be exploited in the large-area detection of pythons. The bands investigated are the visible-near infrared (or VisNIR) and the shortwave infrared (SWIR) bands. The results show that there are enough differences in the data collection such that a single band, inexpensive VisNIR band camera may provide reasonable results and a two-band, VisNIR/SWIR combination may provide higher performance results. In this paper, we provide the VisNIR results.

High-capacity ice-recrystallization endpoint assay employing superhydrophobic coatings that is equivalent to the 'splat' assay.

We have developed an ice recrystallization inhibition (IRI) assay system that allows the side-by-side comparison of up to a dozen samples treated in an identical manner. This system is ideal for determining, by serial dilution, the IRI 'endpoint' where the concentration of a sample is reached that can no longer inhibit recrystallization. Samples can be an order of magnitude smaller in volume (<1 µL) than those used for the conventional 'splat' assay. The samples are pipetted into wells cut out of a superhydrophobic coating on sapphire slides that are covered with a second slide and then snap-frozen in liquid nitrogen. Sapphire is greatly superior to glass in its ability to cool quickly without cracking. As a consequence, the samples freeze evenly as a multi-crystalline mass. The ice grain size is slightly larger than that obtained by the 'splat' assay but can be followed sufficiently well to assess IRI activity by changes in mean grain boundary size. The slides can be washed in detergent and reused with no carryover of IRI activity even from the highest protein concentrations.

Comparison between intranasal dexmedetomidine and intranasal ketamine as premedication for procedural sedation in children undergoing MRI: a double-blind, randomized, placebo-controlled trial.

INTRODUCTION: Providing anesthesia to children undergoing MRI is challenging. Adequate premedication, administered noninvasively, would make the process smoother. In this study, we compare the efficacy of intranasal dexmedetomidine (DXM) with the intranasal administration of ketamine for procedural sedation in children undergoing MRI. METHODS: We studied 150 children, between 1 and 10 years of age, divided randomly into three groups (DXM, K, and S). For blinding, every child received the intranasal drugs twice; syringe S1, 60 min before, and syringe S2, 30 min before intravenous (IV) cannulation. For children in group DXM, S1 contained DXM (1 µg/kg) and S2 was plain saline. Children in group K received saline in S1 and ketamine (5 mg/kg) in S2 whereas children in group S received saline in both S1 and S2. The child's response to drug administration, ease of IV cannulation, the satisfaction of the anesthesiologist and child's parents with the premedication, and the total propofol dose required for the satisfactory conduct of the procedure were compared. We also compared the time to awakening and discharge of the child as well as the occurrence of any side effects with these drugs. RESULTS: Both DXM and ketamine were equally effective as premedication in these patients. Most of the children accepted the intranasal drugs with minimal discomfort; 90.4 % of the anesthesiologists in the DXM group and 82.7 % in the ketamine group were satisfied with the conditions for IV cannulation whereas only 21.3 % were satisfied in the saline group. The total dose of propofol used was less in the study groups. Furthermore, children in group DXM and group K had earlier awakening and discharge than those in group S. CONCLUSION: DXM and ketamine were equally effective, by the intranasal route, as premedication in children undergoing MRI.

Lambrinudi Triple Arthrodesis with Posterior Tibial Tendon Transfer in Adult Fixed Equinus Deformity: Case Report.

Introduction: Fixed Equinus deformity is characterized by limited dorsiflexion of ankle joint and restricted passive movement, along with medial and lateral tibiotalar instability, progressive hindfoot varus, and a supination deformity of the forefoot. Degree of equinus deformity is determined by the Tibio-Metatarsal (TM) angle, subtended between the longitudinal axes of Tibia and 1st Metatarsal, in lateral view of foot. Lambrinudi triple arthrodesis involves the surgical fusion of the talonavicular, talocalcaneal, and calcaneocuboid joints to correct fixed foot deformities, to relieve pain from joint, to provide stability to the imbalanced foot, and to create a plantigrade foot. We combined a Lambrinudi type arthrodesis with a transfer of the posterior tibial tendon (PTT) in adult patients to provide dynamic dorsiflexion and pronation. Case Report: The case was of 39-year-old male diagnosed as fixed cavoequinus deformity of right foot and ankle, who was operated with Lambrinudi triple arthrodesis with PTT transfer in January 2019 and followed up to 5 years. Outcome measurements included radiographic and clinical investigations, including the TM Angle, American Orthopaedic Foot and Ankle Society (AOFAS) Score and Ankle range of motion (ROM), which were assessed preoperatively, immediate postoperatively, at 3 months, 6 months, 1 year, and 5 years.The TM angles were 177, 133, 125, and 122, at pre-operative, immediate post-operative, 3 months, 5 years, respectively. Fusion was seen at 1-year follow-up. Improvement in AOFAS Score with values 38, 57, 73, and improvement in Ankle ROM with values 0 (fixed), 10, 15° at pre-operative, 3 months, and 5 years postoperative, respectively. Patient could use ordinary footwear afterward and had no significant subjective pain or pain which affected his daily activities, but patient had post-procedural right lower limb shortening of 1 cm.. Conclusion: This combined procedure demonstrated clinical correction of foot deformity and significant improvement in functional outcome in the form of AOFAS score and Ankle ROM. The ability of all patients to use normal shoes and significant reduction in pain scores represent ultimately, the improvement in quality of life. We have corrected muscle imbalance and provided dynamic force for dorsiflexion and pronation of foot in the form of tibialis posterior.

Size-structure-property relationship of wood particles in aqueous and dry insulative foams.

Three size-fractionated samples of pine beetle-killed wood particles were used to prepare lightweight insulative foams. The foams were produced by foam-forming an aqueous slurry containing wood particles (125-1000 µm), a polymer binder, and surfactant, followed by oven drying. The effect of wood particle size on the aqueous foam stability, structure, and performance of insulative foams was investigated. While all aqueous foams were highly stable, aqueous foam stability increased with decreasing particle size. For dry foams, the cell size distribution was similar for all particle sizes as it was primarily controlled by the surfactant; differences occurred within the cell wall structure. A size-structure-property relationship was identified using x-ray micro-computed tomography where smaller particles produced lighter cell wall frameworks, leading to lower densities and decreased thermal conductivity and compressive strength. Larger particles produced denser cell wall frameworks that were more resistant to deformation, although all dry foams had sufficient mechanical properties for use as insulation panels. Thermal conductivity for all wood particle size-fractionated samples was <0.047 W m-1 K-1 making the foams similar to expanded polystyrene/polyurethane and supporting their use as thermal insulation in buildings.

Capillary wave tweezer.

Precise control of microparticle movement is crucial in high throughput processing for various applications in scalable manufacturing, such as particle monolayer assembly and 3D bio-printing. Current techniques using acoustic, electrical and optical methods offer precise manipulation advantages, but their scalability is restricted due to issues such as, high input powers and complex fabrication and operation processes. In this work, we introduce the concept of capillary wave tweezers, where mm-scale capillary wave fields are dynamically manipulated to control the position of microparticles in a liquid volume. Capillary waves are generated in an open liquid volume using low frequency vibrations (in the range of 10-100 Hz) to trap particles underneath the nodes of the capillary waves. By shifting the displacement nodes of the waves, the trapped particles are precisely displaced. Using analytical and numerical models, we identify conditions under which a stable control over particle motion is achieved. By showcasing the ability to dynamically control the movement of microparticles, our concept offers a simple and high throughput method to manipulate particles in open systems.

Impairments of Spatial Memory and N-methyl-d-aspartate Receptors and Their Postsynaptic Signaling Molecules in the Hippocampus of Developing Rats Induced by As, Pb, and Mn Mixture Exposure.

Exposure to metal mixtures is recognized as a real-life scenario, needing novel studies that can assess their complex effects on brain development. There is still a significant public health concern associated with chronic low levels of metal exposure. In contrast to other metals, these three metals (As, Pb, and Mn) are commonly found in various environmental and industrial contexts. In addition to additive or synergistic interactions, concurrent exposure to this metal mixture may also have neurotoxic effects that differ from those caused by exposure to single components. The NMDA receptor and several important signaling proteins are involved in learning, memory, and synaptic plasticity in the hippocampus, including CaMKII, postsynaptic density protein-95 (PSD-95), synaptic Ras GTPase activating protein (SynGAP), a negative regulator of Ras-MAPK activity, and CREB. We hypothesized that alterations in the above molecular players may contribute to metal mixture developmental neurotoxicity. Thus, the aim of this study was to investigate the effect of these metals and their mixture at low doses (As 4 mg, Pb 4 mg, and Mn 10 mg/kg bw/p.o) on NMDA receptors and their postsynaptic signaling proteins during developing periods (GD6 to PD59) of the rat brain. Rats exposed to As, Pb, and Mn individually or at the same doses in a triple-metal mixture (MM) showed impairments in learning and memory functions in comparison to the control group rats. Declined protein expressions of NR2A, PSD-95, p- CaMKII, and pCREB were observed in the metal mix-exposed rats, while the expression of SynGAP was found to be enhanced in the hippocampus as compared to the controls on PD60. Thereby, our data suggest that alterations in the NMDA receptor complex and postsynaptic signaling proteins could explain the cognitive dysfunctions caused by metal-mixture-induced developmental neurotoxicity in rats. These outcomes indicate that incessant metal mixture exposure may have detrimental consequences on brain development.

Rapid Mass Spectrometric Calibration and Standard Addition Using Hydrophobic/Hydrophilic Patterned Surfaces and Discontinuous Dewetting.

The rapid calibration chip (RCC) is a device that uses the fast and reproducible wetting behavior of hydrophilic/hydrophobic patterned surfaces to confine a series of differently sized droplets on a substrate to obtain a calibration curve. Multiple series of droplets can be formed within seconds by dipping an RCC into a calibration solution. No pipetting, sequential droplet deposition, or advanced equipment is required. The performance and reproducibility of RCCs were evaluated with an electrospray ionization triple-quadrupole mass spectrometer equipped with a liquid microjunction-surface sampling probe (LMJ-SSP) that allows for fast sampling of surfaces. Using circular hydrophilic areas with diameters ranging from 0.25 to 2.00 mm, liquid volumes of 4.6-70.6 nL could be deposited. Furthermore, the use of a second hydrophobic/hydrophilic patterned transfer chip can be used to add internal standard solutions to each calibration spot of the RCC, allowing to transfer a liquid volume of 22.5 nL.

Sarcopenia is the independent predictor of mortality in critically ill patients with cirrhosis.

Background: Sarcopenia is strongly associated with poor outcome in cirrhosis. There are little prospective data that sarcopenia influences outcomes in critically ill cirrhotics (CICs). Computed tomography (CT) is the gold standard for sarcopenia assessment in the intensive care unit (ICU), as it is independent of hydration status. Aim: This study aims to assess the prevalence of sarcopenia and study its impact on clinical outcomes in CICs. Methods: In this prospective observational study, CICs admitted to the liver ICU were enrolled, if meeting inclusion (age 18-70 years, abdominal CT scan within three months before ICU admission) and exclusion criteria (survival likely to be <24 h, coexisting chronic diseases). Clinical, hemodynamic, biochemical, and nutritional parameters, including length of stay (LOS), duration of mechanical ventilation (MV), development of new-onset infections (NOI), incidence of new-onset acute kidney injury (AKI), and overall survival, were recorded. CT images at the L3 level were analyzed using Slice-O-Matic V4.3 software to assess the skeletal muscle index (SMI) expressed as skeletal muscle area (cm2)/height (m2). Sarcopenia was defined if SMI was <50 cm2/m2 - males and <39 cm2/m2 - females. Data were analyzed using SPSS version 22. Results: Altogether 111 patients (M-83.8%; age 48.4±11.3 years; etiology: Alcohol - 56 [50.5%], non-alcoholic steatohepatitis - 27 [24.3%], viral - 12 [10.8%], and others - 16 [14.4%]; Child-Turcotte-Pugh - 11.9±1.8; model for end-stage liver disease - 27.8±7.3; sequential organ failure assessment - 10.5±4.1; APACHE - 23±8; and MV - 54 [48.6%]) were enrolled. Of these, 76 (68.5%) were sarcopenic and 35 (31.5%) non-sarcopenic. Sarcopenic CICs had higher overall mortality (72.4%) compared to non-sarcopenics (40%) (P=0.001, OR [95% CI] - 3.93 [1.69-9.12]), and higher prevalence of sepsis at ICU admission (53.9% vs. 31.4%, P=0.027, OR [95% CI] - 1.7 [1.0-2.92]) than non-sarcopenics. LOS, duration of MV, incidence of NOI, and development of new-onset AKI were comparable between groups. Multivariate binary logistic regression showed that sarcopenia, sepsis, and APACHE II score were independently associated with mortality. Conclusion: Two-thirds of CICs have sarcopenia at ICU admission, making them 1.7 times more susceptible to sepsis and increasing the risk of mortality by almost 4-fold in the ICU. Relevance for Patients: Almost 70% of patients with chronic liver disease admitted to the ICU have low muscle mass (sarcopenia). The presence of sarcopenia per se makes them highly prone to infections and increases the chances of death by almost 4-fold; thus, highlighting the importance of nutrition optimization in this patient group.

Identifying critically ill patients with cirrhosis who benefit from nutrition therapy: the mNUTRIC score study.

Background and Aim: Malnutrition increases risk of mortality in critically ill patients with cirrhosis. Modified Nutrition Risk in Critically ill (mNUTRIC) score is a validated tool to identify at risk patients who may benefit from goal-directed nutrition therapy. We aimed to study the association between mNUTRIC score and 28-day mortality in critically ill patients with cirrhosis. Methods: A prospective study was conducted in the liver intensive care unit of a quaternary teaching institute. Baseline and follow-up data pertaining to mNUTRIC score, clinical, hemodynamic, biochemical, nutritional parameters, mechanical ventilation, length of ICU stay, and development of sepsis were collected. Correlation between mNUTRIC score and its modulation by nutritional adequacy was determined. Results: One hundred and fifty patients were enrolled. Out of these, 116 (77%) had a high NUTRIC score (HNS) and 34 (23%) had a low NUTRIC score (LNS). Patients with HNS had higher mortality (54% vs. 10%; P = 0.008), longer mechanical ventilation (P = 0.02), and high incidence of sepsis (32% vs. 2.6%; P = 0.002) compared to LNS. The probability of survival increased with increase in nutritional adequacy (P < 0.01) in patients with HNS. Conclusion: mNUTRIC score is a useful tool for identifying nutrition risk in critically ill patients with cirrhosis. Goal-directed nutrition therapy in patients with HNS can significantly improve survival. Relevance for Patients: Critically ill patients with cirrhosis who are at a higher nutritional risk as identified by the mNUTRIC score may have a better survival benefit if higher calorie and protein adequacy are achieved in the ICU.

A solid-state NMR study of changes in lipid phase induced by membrane-fusogenic LV-peptides.

Membrane fusion requires restructuring of lipid bilayers mediated by fusogenic membrane proteins. Peptides that correspond to natural transmembrane sequences or that have been designed to mimic them, such as low-complexity "Leu-Val" (LV) peptide sequences, can drive membrane fusion, presumably by disturbing the lipid bilayer structure. Here, we assess how peptides of different fusogenicity affect membrane structure using solid state NMR techniques. We find that the more fusogenic variants induce an unaligned lipid phase component and a large degree of phase separation as observed in (31)P 2D spectra. The data support the idea that fusogenic peptides accumulate PE in a non-bilayer phase which may be critical for the induction of fusion.

Surface Acoustic Waves to Control Droplet Impact onto Superhydrophobic and Slippery Liquid-Infused Porous Surfaces.

Superhydrophobic coatings and slippery liquid-infused porous surfaces (SLIPS) have shown their potentials in self-cleaning, anti-icing, anti-erosion, and antibiofouling applications. Various studies have been done on controlling the droplet impact on such surfaces using passive methods such as modifying the lubricant layer thickness in SLIPS. Despite their effectiveness, passive methods lack on-demand control over the impact dynamics of droplets. This paper introduces a new method to actively control the droplet impact onto superhydrophobic and SLIPS surfaces using surface acoustic waves (SAWs). In this study, we designed and fabricated SLIPS on ZnO/aluminum thin-film SAW devices and investigated different scenarios of droplet impact on the surfaces compared to those on similar superhydrophobic-coated surfaces. Our results showed that SAWs have insignificant influences on the impact dynamics of a porous and superhydrophobic surface without an infused oil layer. However, after infusion with oil, SAW energy could be effectively transferred to the droplet, thus modifying its impact dynamics onto the superhydrophobic surface. Results showed that by applying SAWs, the spreading and retraction behaviors of the droplets are altered on the SLIPS surface, leading to a change in a droplet impact regime from deposition to complete rebound with altered rebounding angles. Moreover, the contact time was reduced up to 30% when applying SAWs on surfaces with an optimum oil lubricant thickness of ∼8 µm. Our work offers an effective way of applying SAW technology along with SLIPS to effectively reduce the contact time and alter the droplet rebound angles.

Assessment of contamination of soil due to heavy metals around coal fired thermal power plants at Singrauli region of India.

In the present study, an attempt was made to measure contamination of soil around four large coal-based Thermal Power Plants. The concentration of Cadmium, Lead, Arsenic and Nickel was estimated in all four directions from Thermal Power Plants. The soil in the study area was found to be contaminated to varying degrees from coal combustion byproducts. The soil drawn from various selected sites in each direction was largely contaminated by metals, predominantly higher within 2-4 km distance from Thermal Power Plant. Within 2-4 km, the mean maximum concentration of Cadmium, Lead, Arsenic and Nickel was 0.69, 13.69, 17.76, and 3.51 mg/kg, respectively. It was also observed that concentration was maximum in the prevalent wind direction. The concentration of Cadmium, Lead, Arsenic and Nickel was highest 0.69, 13.23, 17.29 and 3.56 mg/kg, respectively in west direction where wind was prevalent.

Detection of Opioids on Mail/Packages Using Open Port Interface Mass Spectrometry (OPI-MS).

Opioids (and their more potent synthetic analogues) are used therapeutically as effective pain killers; however, recreational use and consequent overdoses are implicated in the deaths of thousands of people across the world annually. Trafficking of opioids and other illegal drugs through international mail has become a significant challenge for law enforcement personnel. Hundreds of millions of letters are sorted by the U.S. and Canadian postal services every day. Chemical analysis of this immense volume of mail requires a very fast sampling/detection method. This work explores the use of real-time mass spectrometry analysis with the recently developed Open Port Interface (OPI) for acoustically dispensed nanoliter volume sample droplets, a type of liquid microjunction surface sampling probe, for rapid and easy non-intrusive detection of fentanyl, heroin, and oxycodone. The OPI coupled to mass spectrometry is a novel sample introduction method that allows the rapid analysis of sample surfaces without preparation or modification. Opioids on different packaging materials (e.g., paper, bubble wrap, Ziploc bags) were rapidly (<10 s) interrogated by the OPI, and the sensitivities of the method compared. Furthermore, an opioid surrogate (caffeine) could be facilely detected on envelopes after processing through postal services.

Correlation of CSF neuroinflammatory molecules with leptomeningeal cortical subcortical white matter fractional anisotropy in neonatal meningitis.

It has been previously hypothesized that the high fractional anisotropy (FA) values in leptomeningeal cortical subcortical white matter (LCSWM) regions of neonatal brain with bacterial meningitis is due to the presence of adhesion molecules in the subarachnoid space, which are responsible for adherence of inflammatory cells over the subarachnoid membrane. The aim of this study was to look for any relationship between FA values in LCSWM regions and various neuroinflammatory molecules (NMs) in cerebrospinal fluid (CSF) measured in neonates with bacterial meningitis. Diffusion tensor imaging was performed on 18 term neonates (median age, 10.5 days) having bacterial meningitis and 10 age-/sex-matched healthy controls. CSF enzyme-linked immunosorbent assay was performed to quantify NMs [soluble intracellular adhesion molecules (sICAM), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta)]. Significantly increased FA values were observed in LCSWM regions of the patients compared to controls. A significant positive correlation was observed between FA values in LCSWM regions and NMs [sICAM (r=0.67, P=.006), TNF-alpha (r=0.69, P=.005) and IL-1beta (r=0.82, P=.000)] in CSF of these patients. No difference in FA values (P=.99) in LCSWM regions was observed between patients with sterile (0.12+/-0.02) and culture-positive CSF study (0.12+/-0.02). FA may be used as noninvasive surrogate marker of NMs in neonatal meningitis in assessing therapeutic response in future.