Analysis of geometric defects in square locally resonant phononic crystals: A comparative study of modeling approachesa).

Phononic crystals can develop defects during manufacturing that alter the desired dynamic response and bandgap behavior. This frequency behavior change can enable successful defect inspection if the characteristic defect response is known. In this study, the behavior of a defective square unit cell comprising a freed and shortened leg is studied using a wave finite element method and an approximate continuous-lumped model to elucidate the defect induced qualitative dynamical features. These metrics are a computationally inexpensive alternative to modeling a defective unit cell within a large pristine array entirely in finite elements. The accuracy of these models is validated by comparing the result to a full finite element model. The impact of a shortened unit cell leg on the behaviors of an infinite array of defective cells and a finite array with a single defect are successfully predicted through dispersion curves and frequency response functions, respectively. These methods reveal defect-induced modes that split the local resonance bandgap of the pristine cell, as well as new anti-resonances resulting from the shortened leg. The study uses both approaches to evaluate the effect of defects in complex phononic crystal geometries and provides a comparative evaluation of the results of each model.

Apparent diffusion coefficient (ADC): A potential in vivo biological surrogate of the incidentally discovered bone lesions at 3T MRI.

PURPOSE: To probe the potential of apparent diffusion coefficient (ADC) to rectify the incidentally detected bone lesion on MRI into benign or malignant lesions. MATERIALS AND METHODS: We retrospectively recruited 44 patients (24 males and 20 females); with 52 bone lesions, who underwent diffusion weighted (DW) imaging using multiple b-values on 3 T MRI. ADC maps were derived and analyzed by two radiologists; blinded to the final diagnosis. The mean ADC values were used for statistical analyses. The diagnosis was deduced by histopathological confirmation; in 32 lesions and strict clinical and imaging follow-up for at least 12 months; in 20 lesions. RESULTS: The mean ADC value (mean±SD) of all malignant tumors (including cartilaginous neoplasms) was [0.92 ± 0.40] × 10-3 mm2/s. This significantly differed from those of both primary benign tumors [1.14 ± 0.24] × 10-3 mm2/s, (p = 0.011), and all non-malignant lesions collectively [1.29 ± 0.44] × 10-3 mm2/s, (p < 0.001). Using mADC value of ≤ 1.1 × 10-3 mm2/s resulted in 86.1% sensitivity and 62.5% specificity for characterizing a lesion as a malignant. The inter-rater reliability was almost perfect (95% CI = 0.954-0.985). CONCLUSION: ADC could be a non-invasive in-vivo surrogate that may be able to discern the incidentally discovered osseous lesions into benign and malignant pathologies and guide further diagnostic workup.

Non-reciprocal wave phenomena in energy self-reliant gyric metamaterials.

This work presents a mechanism by which non-reciprocal wave transmission is achieved in a class of gyric metamaterial lattices with embedded rotating elements. A modulation of the device's angular momentum is obtained via prescribed rotations of a set of locally housed spinning motors and is then used to induce space-periodic, time-periodic, as well as space-time-periodic variations, which influence wave propagation in distinct ways. Owing to their dependence on gyroscopic effects, such systems are able to break reciprocal wave symmetry without stiffness perturbations rendering them consistently stable as well as energy self-reliant. Dispersion patterns, band gap emergence, as well as non-reciprocal wave transmission in the space-time-periodic gyric metamaterials are predicted both analytically from the gyroscopic system dynamics as well as numerically via time-dependent full wave simulations. In addition to breaking reciprocity, the authors show that the energy content of a frictionless gyric metamaterial is conserved over one temporal modulation cycle enabling it to exhibit a stable response irrespective of the pumping frequency.

Cumene hydroperoxide induced changes in oxidation-reduction potential in fresh and frozen seminal ejaculates.

Oxidation-reduction potential (ORP) is a newer integrated measure of the balance between total oxidants (reactive oxygen species-ROS) and reductants (antioxidants) that reflects oxidative stress in a biological system. This study measures ORP and evaluates the effect of exogenous induction of oxidative stress by cumene hydroperoxide (CH) on ORP in fresh and frozen semen using the MiOXSYS Analyzer. Semen samples from healthy donors (n = 20) were collected and evaluated for sperm parameters. All samples were then flash-frozen at -80°C. Oxidative stress was induced by CH (5 and 50 µmoles/ml). Static ORP (sORP-(mV/106 sperm/ml) and capacity ORP (cORP-µC/106 sperm/ml) were measured in all samples before and after freezing. All values are reported as mean ± SEM. Both 5 and 50 µmoles/ml of CH resulted in a significant decline in per cent motility compared to control in pre-freeze semen samples. The increase in both pre-freeze and post-thaw semen samples for sORP was higher in the controls than with 50 µmoles/ml of CH. The change from pre-freeze to post-thaw cORP was comparable. The system is a simple, sensitive and portable tool to measure the seminal ORP and its dynamic impact on sperm parameters in both fresh and frozen semen specimens.

Pole distribution in finite phononic crystals: Understanding Bragg-effects through closed-form system dynamics.

Bragg band gaps associated with infinite phononic crystals are predicted using wave dispersion models. This paper departs from the Bloch-wave solution and presents a comprehensive dynamic systems analysis of finite phononic systems. Closed form transfer functions are derived for two systems where phononic effects are achieved by periodic variation of material property and boundary conditions. Using band structures, differences in dispersion characteristics are highlighted and followed by an analytical derivation of the eigenvalues. The latter is used to derive the end-to-end transfer function of a finite phononic crystal as a function of any given parameters. The analysis reveals intriguing features that explain the evolution of Bragg band gaps in the frequency response. It quantifies how the split of eigenvalues into sub- and super-band-gap natural frequencies contribute to band gap formation. The unique distribution of poles allows the closely packed sub-band gap natural frequencies to achieve maximum attenuation in the Bode response. At that point, the impact of the super-band-gap frequencies on the opposing side becomes significant causing the attenuation to fade and the band gap to come to an end. Finally, the effect of splitting the poles further apart is presented in both phononic systems, with material and boundary condition periodicities.

On the spatial sampling and beat effects in discrete wave profiles of lumped acoustic metamaterials.

Acoustic metamaterials are sub-wavelength locally resonant structures known for their band gap behavior and unique response. To capture their working mechanisms, the analysis typically discretizes the continuum model into lumped cells at the interface with the resonators with a cell size chosen appropriately to satisfy homogenization limits. This paper investigates steady-state wave profiles computed from the numerically obtained displacement field of the adjacent discrete cells. It is shown that predicted wave properties often deviate from those obtained via dispersion analysis of the unit cell. For a metamaterial comprised of a finite series of locally resonant cells, the resolution of the discretized waves on both sides of the band gap depends heavily on the shape of the dispersion branches, excitation frequencies, spacing, and properties of the cell constituents. A few examples are used to show the effect of these parameters on the spatial sampling of the propagating wave at both acoustic and optic modes, and the consequences of inadequate resolution on the harmonic response such as apparent modulation of longer wavelengths and beat-like effects in the resultant profiles. These effects are explained in light of defined parameters such as the number of cells per wavelength and the equivalent spatial Nyquist rate.

Inflammatory and Non-inflammatory Breast Cancer: A Potential Role for Detection of Multiple Viral DNAs in Disease Progression.

BACKGROUND: Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. Multiple viral infections in IBC tissues were found to be associated with disease pathogenesis. OBJECTIVE: The aim of the present study was to correlate the incidence of viral DNA with breast cancer progression. MATERIALS AND METHODS: Overall, 135 women diagnosed with breast cancer were enrolled in this study. Using polymerase chain reaction and sequencing assays, we determined the incidence of human papillomavirus types 16 and 18 (HPV-16 and -18), human cytomegalovirus (HCMV), Epstein-Barr virus, human herpes simplex virus type 1 and 2, and human herpes virus type 8 (HHV-8) in breast carcinoma tissue biopsies. We also assessed the expression of the cell proliferation marker Ki-67 by immunohistochemistry in association with the incidence of viral DNA. RESULTS: HCMV and HPV-16 were the most detected viral DNAs in breast carcinoma tissues; however, the frequency of HCMV and HHV-8 DNA were significantly higher in IBC than non-IBC tissues. Moreover, the prevalence of multiple viral DNAs was higher in IBC than non-IBC tissues. The incidence of multiple viral DNAs positively correlates with tumor size and number of metastatic lymph nodes in both non-IBC and IBC patients. The expression of Ki-67 was found to be significantly higher in both non-IBC and IBC tissues in which multiple viral DNAs were detected. CONCLUSIONS: The incidence of multiple viral DNAs in IBC tissues was higher compared with non-IBC tissues. The present results suggest the possibility of a functional relationship between the presence of multiple viral DNAs and disease pathogenesis.

Inflammatory breast cancer: high incidence of detection of mixed human cytomegalovirus genotypes associated with disease pathogenesis.

Inflammatory breast cancer (IBC) is a highly metastatic, aggressive, and fatal form of breast cancer. Patients presenting with IBC are characterized by a high number of axillary lymph node metastases. Recently, we found that IBC carcinoma tissues contain significantly higher levels of human cytomegalovirus (HCMV) DNA compared to other breast cancer tissues that may regulate cell signaling pathways. In fact, HCMV pathogenesis and clinical outcome can be statistically associated with multiple HCMV genotypes within IBC. Thus, in the present study, we established the incidence and types of HCMV genotypes present in carcinoma tissues of infected non-IBC versus IBC patients. We also assessed the correlation between detection of mixed genotypes of HCMV and disease progression. Genotyping of HCMV in carcinoma tissues revealed that glycoprotein B (gB)-1 and glycoprotein N (gN)-1 were the most prevalent HCMV genotypes in both non-IBC and IBC patients with no significant difference between patients groups. IBC carcinoma tissues, however, showed statistically significant higher incidence of detection of the gN-3b genotype compared to non-IBC patients. The incidence of detection of mixed genotypes of gB showed that gB-1 + gB-3 was statistically significantly higher in IBC than non-IBC patients. Similarly, the incidence of detection of mixed genotypes of gN showed that gN-1 + gN-3b and gN-3 + gN-4b/c were statistically significant higher in the carcinoma tissues of IBC than non-IBC. Mixed presence of different HCMV genotypes was found to be significantly correlated with the number of metastatic lymph nodes in non-IBC but not in IBC patients. In IBC, detection of mixed HCMV different genotypes significantly correlates with lymphovascular invasion and formation of dermal lymphatic emboli, which was not found in non-IBC patients.

Promoter hypermethylation and suppression of glutathione peroxidase 3 are associated with inflammatory breast carcinogenesis.

Reactive oxygen species (ROS) play a crucial role in breast cancer initiation, promotion, and progression. Inhibition of antioxidant enzymes that remove ROS was found to accelerate cancer growth. Studies showed that inhibition of glutathione peroxidase-3 (GPX3) was associated with cancer progression. Although the role of GPX3 has been studied in different cancer types, its role in breast cancer and its epigenetic regulation have not yet been investigated. The aim of the present study was to investigate GPX3 expression and epigenetic regulation in carcinoma tissues of breast cancer patients' in comparison to normal breast tissues. Furthermore, we compared GPX3 level of expression and methylation status in aggressive phenotype inflammatory breast cancer (IBC) versus non-IBC invasive ductal carcinoma (IDC). We found that GPX3 mRNA and protein expression levels were downregulated in the carcinoma tissues of IBC compared to non-IBC. However, we did not detect significant correlation between GPX3 and patients' clinical-pathological prosperities. Promoter hypermethylation of GPX3 gene was detected in carcinoma tissues not normal breast tissues. In addition, IBC carcinoma tissues showed a significant increase in the promoter hypermethylation of GPX3 gene compared to non-IBC. Our results propose that downregulation of GPX3 in IBC may play a role in the disease progression.

Treatment of hepatitis C virus infection in patients on maintenance hemodialysis: a single United Arab Emirates center experience.

BACKGROUND: Hepatitis C is prevalent among hemodialysis patients. In patients with normal kidney function, treatment with pegylated interferon and ribavirin can lead to eradication of HCV (hepatitis C virus). But the treatment is more problematic in patients with impaired kidney function, in part due to the altered pharmacokinetics of these medications. Despite recent guidelines, the optimal strategy in this group of patients is not well defined. METHOD: In a retrospective study, we reviewed all patients with chronic hepatitis C on hemodialysis treated at Sheikh Khalifa Medical City, in the United Arab Emirates between 2003 and 2009. The aim of our study was to determine the rate of sustained viral response (SVR) and to establish the safety and rate of dropouts in the different treatment regimens used (patients treated with peginterferon only and patients treated with peginterferon and low dose ribavirin). RESULTS: 22 patients were treated during this period. 5 patients received monotherapy with a reduced dose of peginterferon alfa 2b s.c. once weekly while 17 patients were treated with a combination of reduced dose of peginterferon alfa 2a or 2b s.c. once weekly and a low dose ribavirin (200mg/day). A SVR was achieved in 73% (16/22 patients) of the total patient population and in 76% (13/17 patients) in the sub-group of patients treated with a combination therapy. The tolerability was high. No patients had to discontinue their treatment. The use of ESA (erythropoietin stimulating agents) and G-CSF was common in the combination therapy (94% and 53% respectively). CONCLUSION: In our study of patients on hemodialysis with chronic hepatitis C, the use of peginterferon or a combination of peginterferon with a low daily dose of ribavirin achieved a high rate of SVR and the rate of dropout was low after pursuing an aggressive management of side effects.

Contrast visibility for indirect MR arthrography with different protein contents and agent relaxivities at different field strengths: an in vitro model.

OBJECTIVES: Protein binding and relaxivity are major determinants of the relative effectiveness of an MR arthrographic contrast agent. We sought to evaluate the optimal concentrations of high and usual relaxivity agents in two different proteinous environments at variable field strength for two MR contrast agents of different relaxivities. MATERIALS AND METHODS: At 1.5, 3.0 and 7.0 T, gadobenate dimeglumine (Multihance) with high-relaxivity in proteinous environment and gadoteridol (Prohance) with more typical behavior were studied at 1.25, 2.5, 5, and 10 mmol in 1.7 g/dL and 3g/dL albumin (mimicking protein content of normal and inflammatory synovial fluids, respectively) vs. pure normal saline, as a control. Analysis of image signal intensity (SI) and relaxivity values was done. RESULTS: In our study a change in concentration had no significant effect on T1 SI. In contrast, nearly every change in concentration led to a significant change in T2 SI. In 1.25 mmol concentration, there was no effect on T1 SI of either protein concentrations while higher concentrations showed significant decreased SI in either protein carrier compared to saline. The SI of Gadoteridol was significantly higher (p<0.0001) than that of gadobenate at each of 3T and 7 T, but was significantly lower (p<0.001) at 1.5 T in saline solution while this was not significant for either protein carrier. Both protein carriers had significant effect on T1 (p=0.0124) and T2 (p=0.0118) relaxivities. Also solution concentration significantly (p<0.01) affected both T1 and T2 relaxivities. Field strength did not affect T1 relaxivity (p=0.02511) while it significantly affected T2 relaxivity (p<0.001). This was significant (p=0.035) in case of gadoteridol at 3T. CONCLUSION: 1.25 mmol concentration of both gadoteridol and gadobenate solutions yields the best diagnostic T1 SI specially in higher fields (3T and 7 T) and avoid the deleterious effect of increasing concentration on T2 SI. Gadoteridol is suggested on 3T field indirect MR arthrograms. Protein had no positive effect on either SI or relaxivities in any joint model.

An integrated approach for solving urban water and wastewater crises in the Arabian Gulf States.

Various environmental and economic aspects of urban water and wastewater crises in a number of the Arabian Gulf States are discussed. An integrated approach, which considers simultaneously the problems of urban waters (shortage of water supply and problems associated with urban drainage) and those in connection with wastewater (i.e. environmental impact) is proposed. The feasible link between the main factors affecting these problems and the anticipated results encourage the implementation of the proposed approach. The conclusions suggest immediate municipal legislation.

Midfacial degloving approach for malignant maxillary tumors.

PURPOSE: The aim of this work is to study the use of this technique in extirpation of malignant tumors of the maxillary sinus. This includes the exposure for adequate tumor resection and the preservation of as much as possible functional tissue integrity. This approach will be evaluated including the advantages and disadvantages as regards the physiological function, aesthetic outcome and the complications related to the procedure. METHODS: Fourteen patients underwent the midfacial degloving technique for excision of malignant maxillary sinus tumors during the period from 1999 to 2003 at the National Cancer Institute, Cairo University. This procedure uses 4 basic incisions; sublabial incision, bilateral intercartilaginous incision, septocolumellar-complete transfixion incisions, and bilateral pyriform aperture incisions extending to the vestibule. Immediate reconstruction of the palatal defect was done in all cases by prosthetic obturator. RESULTS: All patients successfully underwent the planned procedures through the midfacial degloving approach for the treatment of malignant lesions of the maxilla without significant complications. Fifty of the patients had immediate postoperative face edema which resolved within a week. Oral infection occurred in 4% of patients. Other sequelae were nasal crusting and infraorbital hypoesthesia, both of which resolved within 2 to 3 months. CONCLUSIONS: The midfacial degloving approach offers a good exposure of the mid third of the face with excellent cosmetic results. This approach may be combined with down fracture of the maxilla for access to expose and resect sinonasal malignancies. The midfacial degloving technique can be considered as a valuable procedure with low mortality and excellent cosmetic outcome.

Myocardial bridges: Their clinical implications and prognostic signs.

Among 980 consecutive selective coronary angiograms performed, nine patients had myocardial bridges of the left anterior descending (LAD) coronary artery. The overall prevalence of myocardial bridges was 0.92%. Among these patients, three patients had coronary artery disease, while six cases were isolated myocardial muscle bridges. With respect to functional abnormality, three had grade III milking effect, three had grade II and three had grade I milking effect. The indications for coronary angiograms were typical chest pain in seven cases and atypical pain in two cases. Their clinical and laboratory investigations are presented with literature review.

Cardiac amyloidosis: Diagnostic features and clinical implications.

Seven patients with cardiac amyloidosis were referred to King Khaled University Hospital. All patients in this study developed congestive heart failure. They had a long duration of illness and thickened ventricular wall with marked abnormalities in the left ventricular filling, and normal systolic function. Diastolic function is suggested as a possible mechanism of congestive cardiac failure in the patients presented.

Prevalence of bicuspid aortic valve and mitral valve prolapse in a healthy Saudi population and the clinical implications of their association.

In this study, 103 Saudi males and 172 Saudi females were referred for medical check-up for employment purposes and/or as undergraduate students. Clinical evaluation of all participants included full cardiovascular examination, with the following investigations being performed: ECG, chest x-ray, and cross-sectional echocardiography. Bicuspid aortic valve was detected in three males and in four females, for a total percentage of 2.5%. Isolated mitral valve prolapse was detected in seven males (6.7%) and six females (3.5%). Association with mitral valve prolapse was reported in five males and seven females, with a total percentage of 4.3%. This association seems to have important etiological, medical and surgical implications.

Clinical spectrum of skeletal abnormalities and mitral valve prolapse and their clinical implications.

Fifty-six patients were diagnosed to have mitral valve prolapse (MVP) syndrome by auscultatory criteria, confirmed by cross-sectional echocardiography. Complete physical examination and x-ray of the bony thorax revealed bony deformities which were subdivided into four main groups according to the predominant deformity. Shallow chest with pectus excavatum, straight back, kyphoscoliosis and elliptical chest in marfanoid patients were reported in the cases studied. It is concluded that musculoskeletal abnormalities have to be considered as nonauscultatory features of MVP. Therefore, any patient with musculoskeletal deformity has to be screened for MVP by cross-sectional echocardiography to prevent life-threatening complications.

Electrocardiographic abnormalities in patients with heat stroke.

Serial electrocardiograms were taken in 46 Hajj Pilgrims suffering from heat stroke immediately after cooling 12 and 24 h later. The collected data were analyzed and revealed that a statistically significant number of patients with heat stroke had sinus tachycardia (43 percent, p < 0.05), conduction defect (22 percent, p < 0.046), prolonged Q-T interval (61 percent, p < 0.007), diffuse nonspecific ST-T changes (26 percent, p < 0.036), and ST-T changes (localized to the ECG leads confirming to a territory of coronary artery) consistent with myocardial ischemia (21 percent, p < 0.02). Although adverse effects of heat stroke on the heart are multifactorial, the above data indicate that heat stroke predisposes to certain risk of myocardial ischemia and conduction disturbances. This may reflect the true cardiovascular status of these heat stroke victims.

Non-invasive evaluation of cardiac abnormalities in heat stroke pilgrims.

Serial electrocardiograms as well as echocardiographic studies of 51 pilgrims suffering from acute heat stroke (mean rectal temperature 41.6 degrees C) were performed. All patients were examined immediately after cooling and 24 h later whenever possible. Regional wall motion abnormalities were detected in 9 cases (17.6%) while pericardial effusion was observed in 13 cases (25%) and asymmetrical septal hypertrophy was detected in 8 cases (15.6%). Other cardiac abnormalities included right ventricular dilatation and increased in left ventricular internal dimensions in 4 cases (7.8%), respectively. Thirteen cases (25.5%) had normal echocardiographic findings. Forty (78%) patients had sinus tachycardia while 8 cases (15.7%) showed atrial fibrillation with uncontrolled ventricular rate, and 3 (5.8%) had sinus bradycardia. Heat stroke electrocardiograms showed tracings demonstrating ST segment depression, compatible with ischaemia in 9 cases, while in 6 cases there were nonspecific T wave changes, whereas in another 4 cases the tracings demonstrated different conduction abnormalities. The collected data were analysed and compared to those of 43 control patients. The adverse effects of heat stroke on the heart are multifactorial requiring the utmost attention and understanding, as they reflect the patient's cardiovascular status.

The spectrum of echocardiographic abnormalities in hypothyroidism and the effect of hormonal treatment.

Cross-sectional echocardiography was used to identify and quantify different cardiac abnormalities in 85 patients with hypothyroidism. Pericardial effusion was the most common and was found in 32 patients (37.6%), while abnormal increase in left ventricular dimensions with impairment of function followed next in frequency (16.4%). Asymmetrical septal hypertrophy as well as segmental wall motion abnormality were each detected in 11.76%. Holosystolic prolapse of the mitral valve was present in only 4.7% of the cases. Different combinations of abnormalities were observed in a total of 22 patients (25.76%), and pericardial effusion was a constant finding. Some of the abnormalities were reversed with physiological thyroxin replacement, but abnormal wall motion remained unimproved.