Effect of Geometry and Orientation on the Tensile Properties and Failure Mechanisms of Compliant Suture Joints.

Compliant sutures surrounded by stiff matrices are present in biological armors and carapaces, providing enhanced mechanical performance. Understanding the mechanisms through which these sutured composites achieve outstanding properties is key to developing engineering materials with improved strength and toughness. This article studies the impact of suture geometry and load direction on the performance of suture joints using a two-stage reactive polymer resin that enables facile photopatterning of mechanical heterogeneity within a single polymer network. Compliant sinusoidal sutures with varying geometries are photopatterned into stiff matrices, generating a modulus contrast of 2 orders of magnitude. Empirical relationships are developed connecting suture wavelength and amplitude to composite performance under parallel and perpendicular loading conditions. Results indicate that a greater suture interdigitation broadly improves composite performance when loading is applied perpendicular to suture joints but has deleterious effects when loading is applied parallel to the joint. Investigations into the failure mechanisms under perpendicular loading highlight the interplay between suture geometry and crack growth stability after damage initiation occurs. Our findings could enable a framework for engineering composites and bio-inspired structures in the future.

Epidemiological features of cutaneous leishmaniosis and related factors in Bushehr province, southwest of Iran.

Cutaneous leishmaniosis (CL) is one of the most important known infectious skin diseases, and Iran, as a country at high risk of leishmaniosis. This research was carried out to describe the epidemiological status of cutaneous leishmaniosis during 2011-2018 years in Bushehr province. Total, 929 cutaneous leishmaniosis patients were registered in the Bushehr province during this period. Data analysis was carried out using IBM SPSS Statistics, version 22. The data were analyzed using the descriptive statistics, Chi-square test, and Fisher's exact test. The highest frequency was related to the age group of 1-10 years (35.1%). The patients consist (60.4%) males and (39.6%) females. The highest and lowest rates of disease were found in 2011 (16.3%) and 2017 (6.6%), respectively, and in January (16.6%) and September (3.2%), respectively. In terms of the ulcer number, (51%) of the cases had one ulcer, and (23%) had (3-5) ulcers. Dry ulcers made up (68.2%) of ulcers, while the wet ulcers made up (31.8%). The hands had accounted for (37%) of ulcers, the face for (25%), and the feet for (21%). Age of cases was significantly associated with the number and site of ulcers (P<0.001). As well, there was a significant relationship between gender and the number of ulcers (P<0.035). This eight-year study confirmed that in Iran, Bushehr province is one of the endemic areas for the cutaneous leishmaniosis. The increase in the patients in 2018, despite its decrease in previous years, is an alert for coming years. Effective disease prevention, control, and treatment measures are essential. Furthermore, the children, who are a vulnerable population, need the special care and treatment.

Epidemiological features of malaria in Bushehr province, southwest of Iran.

The purpose of this research was to describe the malaria situation in Bushehr province from 2011 to 2018. The current study is a descriptive cross-sectional study based on available data. Between 2011 and 2018, 715 malaria patients were registered in the Bushehr province. The data were analyzed using IBM SPSS Statistics version 22. Male patients made up 92.7% of the total, while female patients made up 7.3%. The age group of 20-29 years had the highest frequency of malaria patients (42.3%), while the age group of over 50 years had the lowest frequency patients (2.5%). Regarding nationality, (96.9%) of malaria patients were Afghans, (2.2%) were Pakistanis, (0.8%) were Iranians, and (0.1%) were Indians. The disease was reported to be the most prevalent in 2017 and the least common in 2013 (29.6% and 2.6%). During this time, malaria prevalence has risen and fallen. Bushehr county had the greatest malaria prevalence (42%) and was followed by Kangan county (20.1%) and Asaluyeh county (12.9%). In terms of parasites, Plasmodium vivax was responsible for (94%) of the cases, P. falciparum for (2.4%), and mixed infection (P. vivax and P. falciparum) for (3.6%). Regarding disease transmission, (93.6%) was imported, (1%) was relapse, (0.4%) was indigenous, and (1.3%) was relapse and imported. Bushehr province is at risk of transmitting malaria due to suitable climatic conditions for the reproduction of vector mosquitoes. As well, it confronts the threat of imported malaria, which has caused concern in recent years as a result of the increase of job-seeking migrants. Strategies of malaria control, basic measures in the field of timely diagnosis and rapid and complete treatment of patients, especially in foreign nationals, vectors control, and preventive approaches are required to eliminate malaria in this province.

Association between platelet, white blood cell count, platelet to white blood cell ratio and sarcopenia in community-dwelling older adults: focus on Bushehr Elderly Health (BEH) program.

BACKGROUND: Sarcopenia is a progressive age-related skeletal muscle disorder associated with harmful impacts on health. The present study aimed to investigate the relation between sarcopenia, platelet (PLT), white blood cell (WBC), and PLT to WBC ratio (PWR) due to the importance of early sarcopenia diagnosis. METHODS: This cross-sectional study was conducted based on the second stage of the Bushehr Elderly Health (BEH) Program. Sarcopenia was defined based on the revised edition of the European Working Group on Sarcopenia in Older People (EWGSOP2) in accordance with the Iranian cut-off point. Univariate and adjusted multivariate logistic regression and linear regression were used to evaluate the associations. RESULTS: The prevalence of sarcopenia among participants was 35.73%. PLT count and PWR were statistically higher in severe sarcopenic participants, while no differences were seen in WBC. In crude analysis, sarcopenia was not associated with quartiles of PLT, WBC, and PWR, while after adjusting for age, marital status, and sex, the association was seen in the fourth quartile of PLT and PWR [OR (95%CI) = 1.40 (1.08 to 1.81), p-value = 0.009 for PLT; OR (95%CI) =1.55 (1.20 to 2.00), p-value =0.001 for PWR]. This association remained significant in the fully adjusted model [OR (95%CI) =1.82 (1.20 to 2.78), p-value =0.005 for PLT; OR (95%CI) =1.57 (1.03 to 2.40), p-value =0.035 for PWR]. Among sarcopenia parameters, PLT count was more likely to be associated with handgrip strength and muscle mass. After stratifying the participants by gender, sarcopenia parameters were no longer statistically significant in men. CONCLUSION: This study showed that PLT and PWR were associated with sarcopenia after considering confounding factors, while this association was not seen in WBC. Moreover, results showed that gender had an important impact on sarcopenia parameters.

Perilacunar bone tissue exhibits sub-micrometer modulus gradation which depends on the recency of osteocyte bone formation in both young adult and early-old-age female C57Bl/6 mice.

Osteocytes resorb and replace bone local to the lacunar-canalicular system (LCS). However, whether osteocyte remodeling impacts bone quality adjacent to the LCS is not understood. Further, while aging is well-established to decrease osteocyte viability and truncate LCS geometry, it is unclear if aging also decreases perilacunar bone quality. To address these questions, we employed atomic force microscopy (AFM) to generate nanoscale-resolution modulus maps for cortical femur osteocyte lacunae from young (5-month) and early-old-age (22-month) female C57Bl/6 mice. AFM-mapped lacunae were also imaged with confocal laser scanning microscopy to determine which osteocytes recently deposited bone as determined by the presence of fluorochrome labels administered 2d and 8d before euthanasia. Modulus gradation with distance from the lacunar wall was compared for labeled (i.e., bone forming) and non-labeled lacunae in both young and aged mice. All mapped lacunae showed sub-microscale modulus gradation, with peak modulus values 200-400 nm from the lacunar wall. Perilacunar modulus gradations depended on the recency of osteocyte bone formation (i.e., the presence of labels). For both ages, 2d-labeled perilacunar bone had lower peak and bulk modulus compared to non-labeled perilacunar bone. Lacunar length reduced with age, but lacunar shape and size were not strong predictors of modulus gradation. Our findings demonstrate for the first time that osteocyte perilacunar remodeling impacts bone tissue modulus, one contributor to bone quality. Given the immense scale of the LCS, differences in perilacunar modulus resulting from osteocyte remodeling activity may affect the quality of a substantial amount of bone tissue.

Prevalence of vitamin D deficiency and its associated risk factors among rural population of the northern part of the Persian Gulf.

BACKGROUND: Accumulating evidence indicates that vitamin D deficiency has been increased globally over the last two decades. However, the majority of these studies are concerned with cities and there is scant information regarding the prevalence of vitamin D in rural areas. The main aim of this study was to investigate the prevalence of vitamin D deficiency and its associated risk factors among the rural population in Bushehr province which shares the longest border with the Persian Gulf. METHODS: The rural inhabitants of more than 25 years old from three mountainous, plain, and seashore areas of Bushehr province were selected through a stratified multi-cluster random sampling method. After obtaining the participants' demographic and anthropometric data and their past medical history, serum 25-hydroxyvitamin D [25(OH)D] was measured using ELISA. RESULTS: A total of 1806 (means ±SD, 46± 14years old) rural subjects (35 % males and 65 % females) participated in this study. The prevalence of vitamin D deficiency, insufficiency, and sufficiency were 28 %, 50 %, and 22 %, respectively. The deficiency of vitamin D in women was higher than in men (OR=1.27, 95 % CI: 1.05 to 1.54, P=0.04). There was a positive significant correlation between age and serum vitamin D levels. Men with vitamin D deficiency had higher BMI (P=0.008); this association was not observed among women (P=0.7). There was no significant difference between the food item's consumption frequencies, and vitamin D status (P>0.05). The mountainous, and plain areas had the highest and lowest vitamin D levels, respectively. CONCLUSIONS: Although, Bushehr province is located in a sunny part of Iran, the prevalence of vitamin D deficiency was high among its rural population. The shift of their lifestyle patterns and rapid industrialization in these rural areas may be responsible. Therefore, the enrichment of dietary sources with vitamin D and the use of vitamin D supplements are recommended to tackle the high prevalence of vitamin D deficiency in the rural population of the northern part of the Persian Gulf.

Additive manufacturing of channeled acoustic topological insulators.

We propose and fabricate an acoustic topological insulator to channel sound along statically reconfigurable pathways. The proposed topological insulator exploits additive manufacturing to create unit cells with complex geometry designed to introduce topological behavior while reducing attenuation. We break spatial symmetry in a hexagonal honeycomb lattice structure composed of a unit cell with two rounded cylindrical chambers by altering the volume of each chamber, and thus, observe the quantum valley Hall effect when the Dirac cone at the K-point lifts to form a topologically protected bandgap. Moderately protected edge states arise at the boundary between two regions with opposite orientations. The resulting propagation of a topologically protected wave along the interface is predicted computationally and validated experimentally. This represents a first step towards creating reconfigurable, airborne topological insulators that can lead to promising applications, such as four-dimensional sound projection, acoustic filtering devices, or multiplexing in harsh environments.

Association between anemia, physical performance and cognitive function in Iranian elderly people: evidence from Bushehr Elderly Health (BEH) program.

BACKGROUND AND OBJECTIVES: The present study aimed to investigate the relation between anemia and hemoglobin (Hgb) concentration, physical performance, and cognitive function in a large sample of Iranian elderly population. METHODS: Data were collected from Bushehr elderly health (BEH) program. A total of 3000 persons aged ≥60 years were selected through multistage random sampling. Hemoglobin values lower than 12 and 13 g/dL were considered as anemia for women and men, respectively. The cognitive function was measured using the Mini-cog test and Category fluency test (CFT), and the physical function was measured using handgrip strength (muscle strength), Relative handgrip strength (RHGS), and 4.57-m usual gait speed. Univariate and adjusted multivariate logistic regression and linear regression with Stata MP (version 15) were run, and a p-value of < 0.05 was used as statistically significant for all analyses. RESULTS: Among participants, 7.43% were anemic, and 115 (51.57%) simultaneously had anemia and cognitive disorder. There were significant associations between red blood cell count (RBC), hemoglobin (Hgb), platelet count (PLT), and hematocrit percentage (HCT) with cognitive impairment. Additionally, Hgb concentration was significantly associated with all physical measures (Mean handgrip, Relative handgrip, and usual gait speed) and late recall (mini-cog) among the whole participants. This association remained statistically significant after considering multi-cofounders. In contrast, after stratifying the participants by gender, the association between Hgb concentration and usual gait speed was decreased in both men and women; moreover, Hgb association with cognitive measures (category fluency test and late recall) was no longer significant (all p-values > 0.05). CONCLUSION: There was a cross-sectional and significant association between anemia and functional variables (e.g., Relative and mean handgrip) in Iranian elderly population, whereas Semantic memory, Late recall, and walking were more affected by gender.

Diet, exposure to polycyclic aromatic hydrocarbons during pregnancy, and fetal growth: A comparative study of mothers and their fetuses in industrial and urban areas in Southwest Iran.

The presence of polycyclic aromatic hydrocarbons (PAHs) in the fetal environment is a high-priority concern due to the fetus being more sensitive than adults to these ubiquitous xenobiotics. The aim of the present study was to compare the maternal and fetal serum levels of ΣPAHs and their effects on fetal growth in an industrial and an urban area in Southwest Iran. The industrial area was the petrochemical and gas area (PGA) of the Central District of Asaluyeh County and the urban area (UA) was the Central District of Bushehr County, Ninety-nine maternal serum (MS) and 99 cord serum (CS) samples from the PGA and 100 MS and 100 CS samples from the UA were collected during May 2018 to February 2019. The mean concentrations of ΣPAHs were significantly (p < 0.05) higher in the PGA than the UA in both MS (157.71 vs. 93.56 µg/L) and CS (155.28 vs. 93.19 µg/L) samples. Naphthalene (NAP) was the predominant PAH detected in all the studied samples. Significant negative associations were found between birth weight and anthracene (ANT) level in MS (ß = -22.917, p = 0.032; weight decrement = 22.917 g for a 1 µg/L increase in ANT); head circumference and chrysene (CHR) level in MS (ß = -0.206, p = 0.023; head circumference decrement = 0.206 cm for a 1 µg/L increase in CHR); and birth height and NAP level in CS (ß = -0.20, p = 0.005; height decrement = 0.20 cm for a 1 µg/L increase in NAP). Maternal diet had a significant effect on the serum levels of PAHs. The results of this study showed that transmission of PAHs from mother to fetus through the cord blood is an important issue and mothers who live in industrial areas and consume PAH-containing foodstuffs, and their fetuses, are more at risk than those living in a non-industrial urban area.

Abundance, composition, and potential intake of microplastics in canned fish.

The existence of microplastics (MPs) in canned fish (tuna and mackerel) samples was investigated and their composition, possible sources and potential intake were assessed. Light and fluorescence microscopy were used for the quantification of potential MPs. Furthermore, micro-Raman microscopy, and scanning electron microscopy coupled with an energy dispersive X-ray were used to identify the polymer types and composition of MPs. The results showed that 80% of samples had at least one plastic particle and fibers were the most abundant shapes of MPs. Moreover, polyethylene terephthalate (32.8%) was the most common polymer type in canned fish samples. The fish, food additives, and contact materials during the cleaning and canning process are possible sources of MPs. Human intake estimation of MPs showed the possibility of plastics absorption by humans who consume canned fish several times/week. Hence, the results of this study showed the importance of MPs' guidelines for food safety and hygiene.

Reconfigurable Floquet elastodynamic topological insulator based on synthetic angular momentum bias.

Originating with the discovery of the quantum Hall effect (QHE) in condensed matter physics, topological order has been receiving increased attention also for classical wave phenomena. Topological protection enables efficient and robust signal transport; mechanical topological insulators (TIs), in particular, are easy to fabricate and exhibit interfacial wave transport with minimal dissipation, even in the presence of sharp edges, defects, or disorder. Here, we report the experimental demonstration of a phononic crystal Floquet TI (FTI). Hexagonal arrays of circular piezoelectric disks bonded to a PLA substrate, shunted through negative electrical capacitance, and manipulated by external integrated circuits, provide the required spatiotemporal modulation scheme to break time-reversal symmetry and impart a synthetic angular momentum bias that can induce strong topological protection on the lattice edges. Our proposed reconfigurable FTI may find applications for robust acoustic emitters and mechanical logic circuits, with distinct advantages over electronic equivalents in harsh operating conditions.

Experimental realization of a reconfigurable electroacoustic topological insulator.

A substantial challenge in guiding elastic waves is the presence of reflection and scattering at sharp edges, defects, and disorder. Recently, mechanical topological insulators have sought to overcome this challenge by supporting back-scattering resistant wave transmission. In this paper, we propose and experimentally demonstrate a reconfigurable electroacoustic topological insulator exhibiting an analog to the quantum valley Hall effect (QVHE). Using programmable switches, this phononic structure allows for rapid reconfiguration of domain walls and thus the ability to control back-scattering resistant wave propagation along dynamic interfaces for phonons lying in static and finite-frequency regimes. Accordingly, a graphene-like polyactic acid (PLA) layer serves as the host medium, equipped with periodically arranged and bonded piezoelectric (PZT) patches, resulting in two Dirac cones at the K points. The PZT patches are then connected to negative capacitance external circuits to break inversion symmetry and create nontrivial topologically protected bandgaps. As such, topologically protected interface waves are demonstrated numerically and validated experimentally for different predefined trajectories over a broad frequency range.

Studies on the cholinesterases inhibiting compounds from the Cassiopea andromeda venom.

Cholinesterase inhibitors find application in the combat and care of several diseases, especially AD. Jellyfish venoms are the most promising sources of potent cholinesterase inhibitors. Therefore, it is of interest to study cholinesterases inhibiting compounds from the Cassiopea andromeda venom. We report bioactive compounds using the GC-MC method followed by molecular modeling and docking data analysis. The GC-MS analysis of the crude venom led to the identification of seven bioactive compounds (C1-C7), comprising the steroidal alkaloids, phenolic and carotenoid derivatives. The venom exhibited inhibitory activities against the cholinesterase enzymes. The compound C2, a Dioxolane steroid, displayed the strongest inhibition on both AChE and BChE activities for further consideration.

Reconfigurable topological insulator for elastic waves.

Inspired by the quantum valley Hall effect, a mechanical topological insulator (TI) purposely built for reconfigurability is proposed and experimentally demonstrated. An aluminum plate serves as the host medium with periodically arranged voids and fixed inclusions used to break mirror symmetry. Reconfigurability is derived from the ability to easily alter the imperfection type (void or fixed inclusion) in any unit cell. The corresponding band structure of the proposed hexagonal unit cell is obtained using numerical means, which documents double-folded Dirac cones at the K-points. The breaking of mirror symmetry results in a topologically protected bandgap. Furthermore, topologically protected edge states (TPES) at the interface of two structures with opposite Chern numbers have been demonstrated numerically, and verified experimentally, for different desired trajectories. These TPES are robust against backscattering at defect locations and sharp bends. The proposed reconfigurable TI can be a stepping-stone platform toward building mechanical logic and circuits, which have advantages over electronic equivalents in harsh operating conditions, or to replace wireless systems near dead-zones of metallic and carbon fiber structures.

Experimental Demonstration of an Ultrabroadband Nonlinear Cloak for Flexural Waves.

Broadband cloaking of flexural waves is a major challenge since the governing equation is not form invariant under coordinate transformations. We fabricate a flexural cloaking structure using only a single material composed of homogeneous and isotropic layers, and then present experimental evidence of the first near-ideal broadband cloak in thin plates. The 3D-printed structure is shown to effectively disguise an object over a broad frequency range (2 kHz-11 kHz). The proposed cloak has potential applications in shielding sensors and sensitive components from vibrations in bridges, automobiles, and aircraft.

Broadband Bending of Flexural Waves: Acoustic Shapes and Patterns.

Directing and controlling flexural waves in thin plates along a curved trajectory over a broad frequency range is a significant challenge that has various applications in imaging, cloaking, wave focusing, and wireless power transfer circumventing obstacles. To date, all studies appeared controlling elastic waves in structures using periodic arrays of inclusions where these structures are narrowband either because scattering is efficient over a small frequency range, or the arrangements exploit Bragg scattering bandgaps, which themselves are narrowband. Here, we design and experimentally test a wave-bending structure in a thin plate by smoothly varying the plate's rigidity (and thus its phase velocity). The proposed structures are (i) broadband, since the approach is frequency-independent and does not require bandgaps, and (ii) capable of bending elastic waves along convex trajectories with an arbitrary curvature.