Width Diameter Research Articles

Vessel diameter polymorphism determines vulnerability-to-embolism curve shape

Summary Sherwin Carlquist proposed several functional interpretations for vessel diameter, including that narrow vessels were hydraulically “safe” while wide diameter vessels were more vulnerable to embolism. He applied these ideas both across species and biomes, and within xylem tissue, where function of growth ring types was inferred from vessel diameter polymorphisms (occurrence of differing vessel diameter classes within a tissue). Following on Carlquist’s ideas, we were interested in evaluating if vessel diameter polymorphism could be linked to vulnerability-to-embolism curve shape. Vulnerability curves were fit with a model that included a continuous shape term (alpha). We predicted that high variation in vessel diameter would result in lower alpha (more r-shaped) curves whereas low variation would produce higher alpha (more s-shaped) curves, with potential for intermediate curve types. Our findings support Carlquist’s functional interpretations of vessel diameter. Vessel diameter polymorphism was strongly correlated to vulnerability curve shape. Homogeneous vessel diameters were associated with more s-shaped curves. As vessel diameter polymorphism increased, alpha declined and curves became more linear. High polymorphism was associated with r-shaped curves. There was no relationship between vessel length and curve shape. Vessel diameter was strongly correlated with a common estimate of embolism resistance (P50), with wider diameter vessels associated with increased vulnerability. Vulnerability curves show enormous variety in shape and scale, and both parameters are likely critical in understanding and predicting plant function. Carlquist’s ecological anatomy data, predictions, and functional inferences will continue to be valuable as we expand our understanding of structure–function links in plant anatomy.

The Influence of Electrode Design on Detecting the Effects of Ferric Ammonium Citrate (FAC) on Pre-Osteoblast through Electrical Cell-Substrate Impedance Sensing (ECIS)

Detection sensitivity is a crucial factor in the application of ECIS sensors. For these biosensors, the electrode configuration has a direct impact on sensitivity, yet few studies on monopolar electrodes have been reported. In this study, ECIS sensor arrays, which have a series of working electrode configuration with a wide diameter range and different electrode number, were fabricated to monitor living osteoblast-like MC3T3-E1 cells. The experimental results revealed that when the electrode diameter was larger than 25 μm, electrodes with smaller diameter and number yielded higher impedance values and generated more impedance shift to cell status change. The membrane capacitance obtained by equivalent circuit fitting was at the same level. When the electrode diameter was even smaller, the results in detection of cell monolayer were opposite, and there was no distinct relationship between impedance and membrane capacitance shift to cell status change and electrode geometry. The proposed sensor chip, allowing for a sustained and stable detection of cellular impedance, provides the basis for the selection of the electrode configuration of monopolar electrodes. The test results of electrodes with a diameter of 25 μm and lower indicated the possibility of single cell impedance measurement, which can provide unique insight into the heterogeneous electrical behavior of cells, and, in this case, the electrode size should be close to the cell size.

Allometric Growth of Common Urban Tree Species in Qingdao City of Eastern China

Allometric growth equations help to describe the correlation between the variables of tree biological characteristics (e.g., diameter and height, diameter and canopy width) and estimate tree dynamics at a given tree dimension. Allometric models of common tree species within urban forests are also important to relate ecosystem services to common urban tree measurements such as stem diameter. In this study, allometric growth models were developed for common tree species used for urban greening on the streets of seven municipal districts in Qingdao city of eastern China. A sampling survey was constructed on an urban–rural gradient to obtain the data of tree diameter, crown width, height to live crown base, and tree height. From these measurements, the crown volume and crown projection area of tree species were calculated. The allometric relationship between two variables was established using quantile regression models (95%, 50%, and 5%) to explore its correlation and the influence of tree species characteristics on urban tree allometry. Our results showed that the correlation of allometric growth of different tree species varied largely due to their own characteristics, and the allometric growth of the same tree species was significantly different as well under the fitting of different quantiles. We found that the relationship between crown width and diameter was stronger than that between tree height and diameter. Moreover, the allometric relationship between crown projection area–diameter and crown width–diameter showed similar fitting. The allometric relationship analysis provide theoretical models and a way to use common field data to support urban forestry management and for the subsequent evaluation and prediction of tree functions and ecosystem services.

Differential development characteristics of secondary pores and effects on pore structure and movable fluid distribution in tight gas sandstones in the lower Permian, northeastern Ordos Basin, China

The lower Permian tight gas sandstones (TGSs) in the northeastern Ordos Basin have developed a complex pore network composed mainly of secondary pores with strong reservoir heterogeneity, which affects evaluation and exploitation of gas resources. In this study, lower Permian TGSs were analyzed through the thin sections, scanning electron microscopy, X-ray diffraction, He porosimetry, high-pressure mercury injection capillary pressure, X-ray computed tomography, and nuclear magnetic resonance experiments to elucidate the differential developmental characteristics of secondary pores and their effects on the pore structures and movable fluid distribution. Secondary pores in the lower Permian TGSs include dissolution pores associated with feldspar dissolution and micropores related to authigenic clay minerals. Based on fractal results, we designated the first-order dissolution pores as those with pore throat diameters greater than 1.98 μm, the second-order dissolution pores as those with pore throat diameters between 0.05 and 1.98 μm, and the pore throats diameters of micropores are mainly smaller than 0.05 μm. Both volumetric feldspar leaching calculations and petrographic statistics suggest that the secondary porosity observed in the lower Permian TGSs may not represent a net increase in porosity and more likely represents a redistribution of the original porosity. Dissolution requires sandstones with nonnegligible initial porosity and permeability: coarse-grained, quartz-rich, low proportion of ductile grains sandstones are more likely to maintain high porosity during burial, and dissolution of coarse-grained feldspar facilitates the development of first-order dissolution pores, thus generating the highest redistributed secondary porosity. The first-order dissolution pores have wide pore throat diameters, which enable seepage of movable fluids; the second-order dissolution pores have intermediate pore throat diameters, which allow moderate movable fluid seepage; and the micropores have small pore throat diameters, which are not conducive to seepage of movable fluids. Combinations of different types of secondary pores lead to differences in pore structures and distributions of movable fluids in the lower Permian TGSs. Specifically, TGSs with high first-order dissolution porosity have better pore structures, corresponding to the highest movable fluid saturation (MFS) and movable fluid porosity (MFP). When micropores dominate the pore system, the pore structure and pore network connectivity are poor, and the MFS and MFP decrease.

Experimental and numerical research on opening size effect of novel short fiber reinforced composite laminates

This study investigates the opening size effect of a novel short fiber reinforced quasi-isotropic composite laminate with unidirectionally arrayed chopped strands (UACS) under tensile load by approaches of simulations and experiments. The layup of [45/0/-45/90]s was used to fabricate novel carbon fiber laminates with various central hole diameter from 4 mm to 10 mm. Low notch sensitivity and strength reduction rate were observed in UACS open-hole laminates. It was found that when the width diameter ratio (d/w) of UACS laminate with open-hole is less than 20%, 80% of the original strength can be maintained, which can greatly reduce the design safety factor. Compared with continuous fiber laminates, high increase rate of strength reduction rate was induced by bi-angled slits with the increasing of open hole diameter. The strain distribution around the hole was affected significantly by bi-angled slits, which also inhibited the initiation and propagation of delamination effectively. The strain concentration factor of UACS laminates increases with the increasing open hole diameter. The damage progression of notched and unnotched UACS laminates were analyzed by simulation method, which are consistent well with experimental results.

Outcome indicators of non-surgical therapy of peri-implantitis: a prospective case series analysis.

This study aims to identify patient and implant indicators influencing the non-surgical therapeutic outcomes of peri-implantitis at 6months of follow-up. This case series involved patients with at least one implant diagnosed with peri-implantitis according to the 2017 World Workshop criteria. Non-surgical therapy consisted of mechanical debridement of the peri-implant pockets combined with metronidazole 500mg 3 times a day for 7days. At baseline and at 6months, clinical and radiographic variables were collected to calculate treatment success (probing pocket depth reduction to 5mm without bleeding on probing or < 5mm irrespective of bleeding on probing at all implant sites, and lack of bone loss progression). The primary outcome was treatment success (%) at 6months. The influence of the patient and implant/prosthetic variables upon disease resolution was assessed through simple and multiple logistic regression analyses at patient and implant level, using generalized estimation equations models. A total of 74 patients and 107 implants were analyzed at 6months. Disease resolution was established in 25.7% of the patients and 24.1% of the implants. Patients with stage IV and grade C periodontitis, inadequate oral hygiene at baseline, and wide diameter (≥ 4.5mm) presented significantly greater treatment failure, whereas smokers and former smokers demonstrated a tendency toward failure. At 6months, there was a significant decrease in probing pocket depth and bleeding on probing of 1.08 ± 1.06mm and 14%, respectively. Radiographically, a significant gain in marginal bone level of 0.43 ± 0.56mm was observed. Disease resolution after non-surgical treatment of peri-implantitis is negatively influenced by the loss of support of the adjacent periodontium, poor baseline oral hygiene, and wide diameter implants (≥ 4.5mm). This study helps to discriminate the clinical situations in which non-surgical treatment is less likely to achieve treatment success at short term.

Improving Quantum Well Tube Homogeneity Using Strained Nanowire Heterostructures.

Bottom-up grown nanostructures often suffer from significant dimensional inhomogeneity, and for quantum confined heterostructures, this can lead to a corresponding large variation in electronic properties. A high-throughput characterization methodology is applied to >15,000 nanoskived sections of highly strained GaAsP/GaAs radial core/shell quantum well heterostructures revealing high emission uniformity. While scanning electron microscopy shows a wide nanowire diameter spread of 540-60+60 nm, photoluminescence reveals a tightly bounded band-to-band transition energy of 1546-3+4 meV. A highly strained core/shell nanowire design is shown to reduce the dependence of emission on the quantum well width variation significantly more than in the unstrained case.

Research on the influence of lubrication performance of hydrodynamic journal bearings based on orthogonal test method

The orthogonal experiment design method is used based on analysis of lubrication of hydrodynamic journal bearing．The effect of structural parameters ( bearing diameter，wide diameter ratio and clearance ratio) and operating parameters ( linear velocity and specific pressure) on lubrication performance of hydrodynamic journal bearings is studied． The results show that the linear velocity and specific pressure have significant influence on maximum oil film pressure of the bearings．The influence of specific pressure and bearing diameter on load capacity of the bearings is significant．The bearing diameter and linear velocity have significant influence on discharge flow of the bearings．The linear velocity has the most significant influence on friction power loss of the bearings when the low viscosity lubricant is used， and the clearance ratio，specific pressure and bearing diameter have a great influence on friction power loss of the bearings when the high viscosity lubricant is used．

Pollen tube invasive growth is promoted by callose.

Callose, a β-1,3-glucan, lines the pollen tube cell wall except for the apical growing region, and it constitutes the main polysaccharide in pollen tube plugs. These regularly deposited plugs separate the active portion of the pollen tube cytoplasm from the degenerating cell segments. They have been hypothesized to reduce the total amount of cell volume requiring turgor regulation, thus aiding the invasive growth mechanism. To test this, we characterized the growth pattern of Arabidopsis callose synthase mutants with altered callose deposition patterns. Mutant pollen tubes without callose wall lining or plugs had a wider diameter but grew slower compared to their respective wildtype. To probe the pollen tube's ability to perform durotropism in the absence of callose, we performed mechanical assays such as growth in stiffened media and assessed turgor through incipient plasmolysis. We found that mutants lacking plugs had lower invading capacity and higher turgor pressure when faced with a mechanically challenging substrate. To explain this unexpected elevation in turgor pressure in the callose synthase mutants we suspected that it is enabled by feedback-driven increased levels of de-esterified pectin and/or cellulose in the tube cell wall. Through immunolabeling we tested this hypothesis and found that the content and spatial distribution of these cell wall polysaccharides was altered in callose-deficient mutant pollen tubes. Combined, the results reveal how callose contributes to the pollen tube's invasive capacity and thus plays an important role in fertilization. In order to understand, how the pollen tube deposits callose, we examined the involvement of the actin cytoskeleton in the spatial targeting of callose synthases to the cell surface. The spatial proximity of actin with locations of callose deposition and the dramatic effect of pharmacological interference with actin polymerization suggest a potential role for the cytoskeleton in the spatial control of the characteristic wall assembly process in pollen tubes.

P666 Effect of anastomotic configuration on Crohn’s Disease recurrence after primary ileocolic resection. A comparative monocentric study of end-to-end versus side-to-side anastomosis.

Abstract Background There is an ongoing debate whether the type of anastomosis following intestinal resection for Crohn’s disease (CD) can have an impact on complications and postoperative recurrence. The aim of the present study is to describe the outcome of side-to-side (S-S) versus end-to-end (E-E) anastomosis after ileocolic resection for CD. Methods A retrospective single center comparative study was conducted in consecutive CD patients who underwent primary ileocecal resection between 2005 and 2013. All patients underwent colonoscopy 6-months postoperatively to assess endoscopic recurrence, defined as modified Rutgeerts’ score &amp;gt;i2b. Surgical recurrence implied reoperation due to CD activity at the anastomotic site. Modified surgical recurrences was defined as the need for re-operation or balloon-dilation. Perioperative factors related to recurrence were evaluated. Results Of the128 patients included, 52 (40.6%) received an E-E anastomosis. Median follow-up was longer in the E-E group (8.62 vs 13.68 years, p&amp;lt;0.001). Apart from the primary anastomosis, patient, disease and surgical characteristics were similar between both groups. Postoperative complications and anastomotic leak were comparable (S-S 6.6% vs E-E 7.7%, p=1.00). During the entire postoperative follow-up, biologicals were used in 55.3% and 63.5% (p=0.37) in S-S and E-E patients, respectively. Endoscopic recurrence did not differ between S-S and E-E patients (40.8% vs 49.0%, p=0.37). However, at ten years follow-up, surgical and modified surgical recurrence rate were significantly higher in the E-E group (19.7% vs 7.4%, p=0.02 and 39.2% vs 14.1%, p=0.001). Type of anastomosis was the only independent risk factor for surgical and modified surgical recurrence. Conclusion The type of anastomosis did not influence endoscopic recurrence and immediate postoperative disease complications. However, the wide diameter and the morphologic characteristic of the stapled S-S anastomosis result in a lower risk for balloon dilatation and surgical reintervention in the long-term.

Influence of Platform-Switched Restoration on Bone Resorption in Patients Treated with Wide-Diameter, External-Hex-Connection Dental Implants: A 10-Year Follow-up Study.

Purpose: To investigate and assess the differences in crestal bone loss (CBL) between wide-diameter, external-hexagon-connection implants restored with platform-switching (PS) and platform-matching (PM) restorations with a follow-up of 10 years. Materials and Methods: This study retrospectively analyzed the updated and enlarged dataset of a 5-year prospective clinical study at 10-year follow-up. The data concerns 182 healthy adult subjects treated in a private dental practice who received a single wide-diameter implant with an external hexagon connection in the molar area, restored with either a PS restoration (test) or PM restoration (control). The amount of CBL was radiographically measured at each annual follow-up, as well as after 5 and 10 years of implant loading. In evaluating the association between the two types of abutments and bone loss (including change over time), a linear mixed effects model was run for longitudinal data. Results: Implants connected with PS restorations exhibited significantly lower reduction (0.25 mm) in CBL than those joined to PM restorations (P < .001; 95% CI from 0.22 to 0.29). However, both groups presented a higher increase in bone loss during the first year (0.58 mm in PS and 0.83 mm in PM) and a linear increment thereafter until the 10-year follow-up (0.046 mm/year; P < .001; 95% CI from .042 to .049). Conclusion: Notwithstanding the limitations of this study, it can be concluded that after 10 years of follow-up, the implant with a wide diameter and external-hexagon connection restored with a PS abutment seems to be more effective in reducing bone loss compared with the PM abutment.

It Is in the Eye of the Beholder: Ocular Ultrasound Enhanced Monitoring of Neurotoxicity after CAR-T Cell Therapy

Usually used in emergency settings, bedside sonographic measurement of optic nerve sheath diameter can aid in diagnosing elevated intracranial pressure. We report a case of a 26-year-old male hospitalized for CAR T-cell therapy with Axicabtagene Ciloleucel for treatment of relapsed diffuse large B-cell lymphoma, who developed progressive symptoms of immune effector cell-associated neurotoxicity syndrome. Fundoscopic examination suggested the presence of blurred optic disc margins. Bedside ocular ultrasound revealed wide optic nerve sheath diameters and bulging optic discs bilaterally. The patient had a ventriculostomy placed for monitoring and received treatment with steroids and mannitol, as well as tocilizumab. After 7 days in the ICU, the patient recovered with no evidence of long-term neurological deficits.

Development of a Diagnostic Model Focusing on Esophageal Dysmotility in Patients with Systemic Sclerosis.

Esophageal dysmotility is a common and neglected complication of systemic sclerosis (SSc) associated with poor prognosis, while the assessment remains a challenge. We aimed to develop a diagnostic model for esophageal dysmotility in SSc patients that provides individualized risk estimates. Seventy-five SSc patients who underwent high-resolution manometry (HRM) were included in the study. Esophageal widest diameter (WED) was measured on a chest CT scan. Esophageal parameters between patients with and without esophageal dysmotility were compared. Multivariate logistic regression analysis and Least Absolute Shrinkage and Selection Operator (LASSO) regression were used to fit the model. The diagnostic model was evaluated by discrimination and calibration. Internal validation was estimated using the enhanced bootstrap method with 1000 repetitions. Sixty-one systemic sclerosis patients (81.3%) were diagnosed with esophageal dysmotility according to the Chicago Classification v 3.0. The diagnostic model for evaluating the probability of esophageal dysmotility integrated clinical and imaging features, including disease duration, ILD, and WED. The model displayed good discrimination with an area under the curve (AUC) of 0.923 (95% CI: 0.837-1.000), a Brier score of 0.083, and good calibration. A high AUC value of 0.911 could still be achieved in the internal validation. The diagnostic model, which combines the disease duration, ILD, and imaging feature (WED), is an effective and noninvasive method for predicting esophageal dysmotility in SSc patients.

Diameter-Dependent Semiconducting Carbon Nanotube Network Transistor Performance

Single-walled carbon nanotube (SWCNT) network based devices show application potentials due to their extraordinary electric and optical properties, and the device performance is largely determined by the network morphology and tube–tube junction interactions. In this work, five SWCNT samples with narrow bandgap distributions covering a wide diameter range of 0.7–1.6 nm were purified by the conjugated polymer extraction (CPE) process. Both chirality distribution and semiconducting purity of these samples were systematically characterized by optical methods. Uniform high density network based thin film transistors (TFTs) were fabricated, and their performance can be related to tube bandgap/diameter and defects density or tube length. The diameter-dependent tube–tube junction resistance, the most important parameter for nanowire network devices, was extracted using a network predictive model. It was found that junction resistance inversely scales with tube diameter and is about 2 orders of magnitude higher than tube intrinsic resistance. The impacts of network morphology, tube diameter, and length on their network TFT performance were further discussed. We hope these results can provide some guideline to address various application challenges for SWCNT network based devices.

ODP271 Primary Aldosteronism and Primary Hyperparathyroidism: A Report of Dual Endocrine Hypertension

Abstract Background Primary aldosteronism (PA) is one of the common causes of secondary hypertension. Primary hyperparathyroidism (PHPT) is a less common etiology of secondary hypertension. The concomitance of both PA and PHPT is very rare, with a possible bilateral positive feedback loop between the adrenal cortex and the parathyroid gland[1]. Clinical case: A 64-year-old female was referred to the endocrine clinic for secondary hypertension assessment. She was diagnosed with hypertension 30 years earlier, poorly controlled on three antihypertensive medications, nifedipine 90 mg daily, lisinopril 40 mg daily, and atenolol 50 mg daily. She started experiencing muscle cramps two years prior to the referral and was found to be hypokalemic on multiple occasions, with potassium ranging between 2.5 to 3 mmol/L. She also had multiple admissions to the emergency department for hypertensive urgencies within the last year. Family history was positive for poorly controlled hypertension in the patient's mother. Physical examination showed class I obesity with a BMI of 31, but otherwise unremarkable. Workup showed elevated aldosterone concentration of 38 ng/dl and suppressed renin concentration (&amp;lt;1 pg/ml) with an aldosterone/renin ratio of 38. Overnight dexamethasone suppression test was normal (cortisol of 1.5 mcg/dl, suppressed ACTH of 5.5 pg/ml, and appropriately elevated dexamethasone of 324 ng/dl). 24-hour urine metanephrine and normetanephrine levels were normal. Imaging showed bilateral adrenal adenomas of about 13-14 mm in widest diameter, with an average density of 10 Hounsfield units. Adrenal venous sampling revealed hyperfunctioning left adrenal with normal right adrenal. The left adrenal gland was removed laparoscopically, and blood pressure normalized postoperatively on the single antihypertensive agent (lisinopril). Interestingly, during the initial workup, the patient also had elevated calcium of 11 mg/dl and low phosphate at 2.5 mg/dl. In addition, parathyroid hormone (PTH) was elevated at 103 and 95 pg/ml on two occasions, with normal 25-OH vitamin D levels. 24-hoururine calcium was 240mg/dl, and creatinine in urine was 76.4 mg/dl. The calcium creatinine clearance ratio was 2.5%. Diagnosis of primary hyperparathyroidism was made. She had no renal stone, chronic kidney disease, or fractures, with a normal DEXA scan. There was no current indication for parathyroidectomy, and the patient continued to be followed up in the clinic. Clinical lesson: Recent evidence shows cross-talk between the adrenal cortex and parathyroid gland. Our patient may represent such a case, with concomitance of two rare endocrinopathies resulting in difficult-to-control hypertension [1,2]. Thus it is essential to investigate multiple etiologies of secondary hypertension. Reference: Brown JM, Vaidya A. Interactions between adrenal-regulatory and calcium-regulatory hormones in human health. Curr Opin Endocrinol Diabetes Obes . 2014;21(3): 193-201. doi: 10.1097/MED. 0000000000000062 Maniero C, Fassina A, Guzzardo V, et al. Primary hyperparathyroidism with concurrent primary aldosteronism. Hypertension. 2011 Sep;58(3): 341-6. doi: 10.1161/HYPERTENSIONAHA.111.173948. Epub 2011 Aug 8. PMID: 21825220. Presentation: No date and time listed

Petrographic and geochemical characteristics of beneficiated metallurgical coal from the No. 6 Seam, Tshipise sub-basin, Soutpansberg coalfield, South Africa

The Soutpansberg Coalfield hosts South Africa's hard coking coal reserves. However, coals in this region are understudied compared to other coalfields in the country. This study characterizes the properties of fine-float fraction samples extracted from a wide diameter borehole core in the Makhado Project, Tshipise sub-basin, Soutpansberg coalfield. Conventional analyses were used to determine the coal quality, petrographic composition, mineralogy, geochemistry (including trace element and rare earth element composition), and free swelling index of samples from six coal horizons and three partings from the economic No.6 Seam. The coal samples are classified as medium rank bituminous C coals (0.88 %RoVmr, 0.92 %Rmax) and are highly vitrinitic in composition (97 vol% mineral matter free (mmf)). The samples show strong caking potential (FSI of 9). The total rare earth concentrations range between 570 and 3193 ppm in the ash samples. Preliminary analysis show all but two samples are promising sources of rare earth elements as the total concentrations exceeded the 1000 ppm cut-off grade. Further research is required to confirm these preliminary findings.

Model Experiment Exploration of the Kinetic Dissipation Effect on the Slit Dam with Baffles Tilted in the Downstream Direction

Slit dams can eliminate the risk of particle overload accumulation, which can be safer in controlling debris flow compared with a completely closed dam. In attempting to better use the energy dissipation effect of particle collision and reduce the impact of the dam body, referring to the traditional slit dam, this paper proposed one with tilted baffles in the downstream direction. Discrete element simulation and several flume model experiments were carried out herein to verify the advantages and explore the applicable conditions of this tilted baffle slit dam, in which the particle trapping efficiency and the change law of impact force of the tilted baffles under the conditions of different inclined angles, opening sizes, and particle sizes were studied. The results show that: 1. when the inclination angle is 30° ≤ θ ≤ 45°, the tilted baffles can dissipate more particle kinetic energy than the transverse baffles; 2. the maximum impact force and trapping efficiency of the tilted baffles decrease with the increase in the width diameter ratio b/d, with the opening width b of the slit to the particle diameter d; 3. with the given particle size of 6 mm ≤ d ≤ 14 mm, the range that the tilted baffles can effectively intercept the particles flowing down is 0 ≤ b/d ≤ 4, and it reaches the ideal interception state near 1 ≤ b/d ≤ 2, where, relatively, the impact force is weak, and the interception efficiency is high.

Experimental analysis of the thermal energy storage potential of a phase change material embedded in additively manufactured lattice structures

Recent literature introduced novel additively manufactured porous metallic structures designed to deliver enhancement of the thermal conductivity of organic phase change materials. Among these, so-called lattice structures are of particular interest for application in lightweight components. Originally investigated for their attractive mass-specific mechanical properties, these geometries were recently proposed, in alternative to metallic foams, as a conductive matrix of phase change materials. However, the geometrical parameters of a lattice structure differ from the ones of a metallic foam and no established data exist in the literature about the influence of the lattice cell geometry on the transient heat transfer enhancement of a phase change material. This work presents an experimental comparison of the thermal behaviour of a composite based on an n-Octadecane paraffin wax embedded in four different aluminium lattices with varying unit cell topology (f2ccz, bcc, bccz, f2bcc), but showing the same cell size, aspect ratio and strut diameter. It is noticed that the unit cell topology affects the transient thermal behaviour beyond its direct effect on the cell porosity. To address this, a specific thermal performance parameter is identified. The sample based on the f2ccz topology represents the best candidate. The influence of orientation with respect to gravity on the heat transfer is also investigated. While the samples show relatively low porosity, ranging from 70.7% to 83.4%, the wide pore diameters lead to a high impact of melt convection on the thermal behaviour of most samples. Up to 28% wall temperature variation is evidenced for different heating orientations.

Eighteen-Year-Old Nulliparous Woman with Massive Mucinous Cystadenoma in Pregnancy: Case Report

Background: Ovarian mucinous cystadenoma is rare in adolescents. We report the diagnosis and management of a massive ovarian mucinous cystadenoma in a pregnant adolescent. Case Presentation: An 18-year-old G1PO was referred by a midwife to the Komfo Anokye Teaching Hospital on account of excessive abdominal distension at 25 weeks’ gestation and an ultrasound scan finding of a large non-septate cystic adnexal mass. She, however,reported to the hospital 6 weeks later with a complaint of worsening abdominal distension and discomfort. A transabdominal ultrasound scan revealed single intrauterine gestation and a large non-septate cystic adnexal lesion measuring more than 19 cm in its widest plane. She had a conservative in-patients management followed by emergency caesarean delivery, exploratory laparotomy and unilateral salpingo-ophorectomy at 33 weeks 1 day. The outcome of the delivery was a 1.8 kg female infant with Apgar score of 4 and 6 at 1 and 5 minutes respectively. A 6.8 kg cystic ovarian mass measuring about 40 cm at its widest diameter was removed.Conclusion: Although pregnancy-associated adnexal masses are not uncommon, significant socio-economic challenges may render the diagnosis and treatment of extremely large pelvic masses in pregnant adolescents difficult. The decision to optimize maternal and fetal outcomes is essential in managing rare conditions in marginalized obstetric populations.

Effective Conductivity of Carbon-Nanotube-Filled Systems by Interfacial Conductivity to Optimize Breast Cancer Cell Sensors.

Interfacial conductivity and “Lc”, i.e., the least carbon-nanotube (CNT) length required for the operative transfer of CNT conductivity to the insulated medium, were used to establish the most effective CNT concentration and portion of CNTs needed for a network structure in polymer CNT nanocomposites (PCNT). The mentioned parameters and tunneling effect define the effective conductivity of PCNT. The impact of the parameters on the beginning of percolation, the net concentration, and the effective conductivity of PCNT was investigated and the outputs were explained. Moreover, the calculations of the beginning of percolation and the conductivity demonstrate that the experimental results and the developed equations are in acceptable agreement. A small “Lc” and high interfacial conductivity affect the beginning of percolation, the fraction of networked CNTs, and the effective conductivity. Additionally, a low tunneling resistivity, a wide contact diameter, and small tunnels produce a highly effective conductivity. The developed model can be used to optimize breast cancer cell sensors.