Results show that among the commonly native point defects in graphene, only the single vacancy 5–9 and divacancy 555–777 have the desirable electronic structures to trap N-containing groups and to mediate the subsequent dehydrogenation processes. The local structure of the defective graphene in combining with the thermodynamic and kinetic effect plays a crucial role in dominating the complex atomic rearrangement to form graphitic-N which heals the corresponding defect perfectly. The importance of the symmetry, the localized force field, the interaction of multiple trapped N-containing groups, as well as the catalytic effect of the temporarily formed bridge-N are emphasized, and the predicted doping configuration agrees well with the experimental observation. Hence, the revealed mechanism will be helpful for realizing the targeted synthesis of N-graphene with reduced defects and desired properties.Nitrogen-doped graphene (N-graphene) has attractive properties that has been widely studied over the years. However, its possible formation process still remains unclear. Here, we propose a highly feasible formation mechanism of the graphitic-N doing in thermally treated graphene with ammonia by performing  Chemical doping is a powerful technique to tailor the properties of carbon materials12325623613146101617Nitrogen-doped graphene (N-graphene) can be fabricated by either direct-synthesis456171927912131621224567121329162268216172151012131756821et al. have reported that a high ratio of graphitic-N/pyridinic-N can provide a promising activity for ORRFor the N-graphene obtained in some experiments56712131719662762417281013et al.3), most of the N-dopants (80%) are graphitic-Ns. It is intuitively clear that graphitic-N forms by merging N atoms into the defect region of graphene. First principles calculations have also proved that the occurrence of N-doping at defects of graphene is energetically favorable2732Post-treatment of graphene with N-precursors has been proved a practical means to achieve high-quality N-graphene which is enriched in graphitic-N but small amounts of defects712ab initio molecular dynamics (ab-MD) simulations at experimental conditions, we investigate the interaction of the widely used N-precursor of NH3 with the graphene of different structures. A highly feasible formation mechanism of graphitic-N is revealed, the defect-configuration relationship is established, the dynamics of the simultaneous formation of graphitic-N and the healing of the defect is visualized, and the important factors which dominate the formation process is emphasized. Thus, our simulations give new insights in N-graphene chemistry and will certainly help to achieve the targeted synthesis of N-graphene with reduced defects and desired doping structures.In this work, by performing As a precondition to occur N-doping, N-sources should be trapped by graphene. We first examined the possibility to trap N atoms at the perfect region of graphene at experimental conditions. A temperature range from 700 to 1000 °C with a step of 50 °C has been used in the simulations, and the snapshots for 850 °C are plotted in Structural defects like Stone-Wales (SW), vacancies, nanoholes, grain boundaries, as well as the edges of graphene are known to possess a relative higher activity2627From the structural point of view, to heal a divacancy requires two adatoms. We have carried out simulations to study the interaction of two N atoms with a DV(5-8-5) and DV(555-777), respectively. Remarkably, only the DV(555-777) has trapped the two N atoms as expected see . Traject3 in thermal treatment experiments is complicated, which may involve various reactions and the products of -NH2, -NH-, and -N are possible. N atom is only the simplest model for the possible N-sources. We continued our simulations to investigate the interaction of a DV(555-777) and SV(5-9) with the N-containing groups of NH3, -NH2, and -NH-, respectively.In sharp contrast to the widespread intuition that a variety of defects in graphene can provide rich active sites for N-doping, our simulations demonstrate clearly that among the commonly native point defects of graphene, only the SV(5-9) and DV(555-777) have the ability to trap N atom, but it seems not always result in the formation of graphitic-Ns. Moreover, the decomposition of NH2 and -NH- can be well trapped by the defect, but the NH3 can not, suggesting that the occurrence of the first step of NH3 decomposition in the thermal treatment experiments does not need the help of the defect. Our simulations also show that although the -NH2 and -NH- can be trapped by the defect, both of them can not dehydrogenate at all, even the simulation time has been extended to 3 ps. It is well known that without dehydrogenation, the formation of N-doping is impossible.The results for DV(555-777) are given in 2 appears at 100 fs, it moves to the defect region and reacts with the first one to form a -NH- and a NH3. The formed NH3 drifts freely above the surface and runs out of the sight as expected. While the formed -NH- adsorbs tightly at the bridge-site of the first 5–7 pair as shown in 2. The formed atomic-N transforms to a pyridinic-N due to merged into the 5–7 pair. Instead of drifting away, he -NH2 moves quickly to the second second 5–7 pair to adsorb on a top-site.We extended our simulations to consider the possible dehydrogenation from the interaction of N-containing groups, and the results are given in 2 → -NH- → atomic-N” route.Remarkably, a DV(555-777) can trap multiply N-containing groups which induce a two-step dehydrogenation process that leads to the formation of an atomic-N. It can be simply represented by the “-NH2 at the third round moves away from the surface of graphene. Surprisingly, although to heal a DV(555-777) requires only two adatoms, as many as three atomic-Ns can be formed at the vicinity.We found that the process continues as more N-containing groups appear at the reaction region, making as many as three atomic-Ns to be formed at the vicinity of a DV(555-777). One can see in As the simulation proceeds further, we found the significance of the coexistence of three atomic-Ns at a divacancy. It is that a complex atomic rearrangement process can be induced, directly resulting in the formation of graphitic-Ns and the healing of the defect. The entire process involves the rotation, break, and formation of multiply bonds as shown in It is worthy of noting that the third N has the same species (bridge-N) at the initial and final stages of the rearrangement. While As a catalyst, the bridge-N should be active and unstable at experimental conditions. This is why bridge-N has never been observed in the N-graphene obtained in experiments. We have performed density functional theory (DFT) calculations and found that the energy barrier for process of “bridge-N → top-N → bridge-N” is about 1.15 eV when considered vdW corrections. This means that the bridge-N migration at the surface of graphene can occur easily at macroscopic time range of the real thermal treatment experiments, but the probability to find the migration in fs-ps time range simulations should be very small. Thus we have only considered what will happen when two bridge-Ns have moved close to each other. The results displayed in 2 → -NH- → atomic-N”, and the result is also basically the same, namely a single graphitic-N (with a configuration of N1) is formed eventually that heals the defect perfectly.We have further extended our simulations to consider the possible formation of graphitic-N at the defect of SV(5-9) and the snapshots are given in Our simulations show that among the native point defects of graphene, only the SV(5-9) and DV(555-777) have the ability to trap N-containing groups and to mediate the subsequent N-doping process. This can be well understood by analyzing the localized force field of the defects.Unambiguously, there exist two major localized force fields at a defect: a strain field (S-field) caused by lattice-disorder and an electronic field (E-field) generated due to the existence of dangling bonds. From a structural point of view, a SW(55-77) is formed by the rotation of a C-C bond of 90° at the perfect region of graphene, thus only the S-field presents at the vicinity. Our simulations show that the S-field of SW(55-77) is not large enough to trap N-containing groups at experimental conditions. But for SV(5-9), it is formed by missing a C atom. There exist three dangling bonds at the vicinity. It undergoes a Jahn-Teller distortion which can lead to the saturation of two of the three dangling bonds, but one dangling bond always remains owing to geometrical reasons. Thus both the S-field and the E-field exist at a SV(5-9), resulting in the localized force field which is large enough to trap N-containing groups.et al.While for DV(5-8-5) and DV(555-777), they both form by missing a pair of C atoms. Self-saturations let no unsaturated C atoms but only lattice-disorder present at the defect. It is well known that a DV(555-777) can be formed from a DV(5-8-5) by the rotation of a C-C bond of 90° 26We noticed that the trapped N atom adsorbs on the top-site of SV(5-9) see , but on 2 and -NH- can not dehydrogenate when only considered the interaction of the N-containing group with graphene, in consistent with the observations of previous studies8272 → -NH- → atomic-N” is revealed in our simulations. It is clear that multiply N-containing groups can be trapped by a SV(5-9) or a DV(555-777), and the interaction between them demonstrates the same route of dehydrogenation at the two defects. This means that the revealed dehydrogenation route is independent on the type of the defects but dominated by the interaction of N-containing groups.Our simulations show that the -NHOur simulations show that without the third atomic-N, the two atomic-Ns can not launch the complex atomic rearrangement process and the N-doping of D3h symmetry. First principles calculations have confirmed that the localized force field of a DV(555-777) extends widely at the vicinity in D3h symmetryD3h symmetry allows three atomic-Ns to be formed at the vicinity of a DV(555-777). The symmetry plays a crucial role in determining the number of the formed atomic-Ns and mediating the formation of It is well known that a DV(555-777) contains four disordered C atoms of, one locates at the center and the other three surround it, resulting in the formation of three 5–7 pairs in 1 and two graphitic-Ns quasi-adjacently occupied the same sublattice (A) of graphene result in the doping configuration of et al.3 are Experimental measurements show that the formed graphitic-Ns can either distribute randomly between the two sublattices of graphene71 and Our ab-MD simulations have certainly resolved this long-lasting issue. Basis on our simulations, the relationship between the native point defects of graphene and the doping configurations of the graphitic-N can be established. Namely, SV(5-9) and DV(555-777) mediate to the formation of N1 or a The finding from our ab-MD simulations is of importance. It reveals for the first time that the DV(555-777) is a favorable active site for N-doping. This is also a somewhat expected result when considering the observation from previous studiesab initio molecular dynamic simulations, we have found a new mechanism for substitutional nitrogen-doping in thermally treated graphene that satisfactorily explains the experimental observations and will be helpful for realizing targeted synthesis of nitrogen-graphene with reduced defects and desired doping configurations.In conclusion, by performing 3 molecule and its decomposing products of -NH2, -NH-, and -N were used as the possible N-containing groups for N-doping. The initial position of the containing group was set to 3.6 Å away from the graphene layer to ensure the elimination of direct chemical interactions. In this case, vdW forces play the dominant role at the initial stage of simulations.A large supercell (15 × 15 × 1) containing 450 C atoms see  was adopζ polarization (DZP) numerical atomic orbital basis sets with the energy cut-off of 80 meV were adopted. The real-space integration was done on the mesh defined by 200 Ry kinetic energy cutoff. Each step was achieved with the tolerance of density matrix (DM) of 1.0−4. The snapshots of the simulations were grabbed using VMD programThe simulations were carried out using ab initio package SIESTA 3.2How to cite this article: Li, X.-F. et al. Unraveling the formation mechanism of graphitic nitrogen-doping in thermally treated graphene with ammonia. Sci. Rep.6, 23495; doi: 10.1038/srep23495 (2016).


The second technique is based on monitoring of potassium concentration in urine. High level of potassium concentration denotes clear occurrence of dehydration. Furthermore, a Wireless Body Area Network (WBAN) was developed for this sensor platform to manage data transfer among devices and the internet. The WBAN coordinator controls the sensor devices and collects and stores the measured data. The collected data is particular to individuals and can be shared with physicians, emergency systems or athletes' coaches. Long-time monitoring of activity and potassium concentration in urine can help maintain the appropriate water intake of elderly people or athletes and to send warning signals in the case of near dehydration. The created sensor system was calibrated and tested in laboratory and real conditions as well. The measurement results are discussed.A non-invasive solution for monitoring of the activity and dehydration of organisms is proposed in the work. For this purpose, a wireless standalone chemical sensor platform using two separate measurement techniques has been developed. The first approach for activity monitoring is based on humidity measurement. Our solution uses new humidity sensor based on a nanostructured TiO From this point of view, interest in wearable portable and hand-held sensors to provide health monitoring functions has increased in the last decades. These sensors are currently in the form of developmental point of care platforms. A number of such sensors with a controlling device can be integrated as a wearable Wireless Body Area Network (WBAN), which can be used for computer-assisted monitoring of chronic diseases, diabetes, asthma, heart attacks or dehydration state as well –8.Water is the most important substance for the human organism and the quantity of fluids influences the correct function of all body cells . The watDehydration of the organism leads to disruption of the cells and brain work and reduces the functioning of metabolic processes. The first symptoms of dehydration appear at the loss of about 2% of the body fluids ,10. Exisetc. [in-situ or wearable sensors, e.g., for human biological processes monitoring [2 films [Sweating process monitoring can be interpreted as a personal activity and it can be determined through the measurements of humidity level close to skin surface as perspiration rate. Activity is also related to water metabolism and it can impact dehydration significantly, but it is difficult to determine dehydration from these data. Therefore, an activity monitor is an additional sensor helping to better understand data from urine sensor and giving feedback to a person in time to avoid dehydration. The sensor should be safe for human body and stable in a salt atmosphere during a long period of time . Metal oxide semiconductor sensors, which also have fast response time, low drift of the parameters and don't have hysteresis, meet these requirements –22. Receetc. –22. Nanonitoring –25 closenitoring ,27, nanonitoring ,29, nanonitoring , nanocomnitoring –33, micr[2 films , titaniu[2 films , nanopow[2 films ,37, nano[2 films  and nano[2 films  or sol-g[2 films  techniqu2 sensor was developed. This sensor has increased sensitivity in the high humidity conditions which occur near the human skin. It uses sensitive element based on array of titanium oxide nanopillars formed by an electrochemical anodizing method.In this work, we propose and develop a sensor platform for non-invasive dehydration detection and monitoring. It is extremely important for elderly people or athletes to prevent serious health problems or sudden death . The pla2 sensor for relative humidity measurement, is innovative. Therefore, the major part of this article is primarily focused on TiO2 sensor development and fabrication due to its novelty and benefits.The concept of wireless sensor platform which combines mentioned sensors for this purpose, as well newly developed TiO2.2.1.The dehydration monitoring system is based on an electrode sensitive to potassium and a device for measurement and wireless data transfer. Potassium concentration is measured by a standard potassium ion selective electrode obtained from Elektrochemické detektory s.r.o.  with potentiometric output according to the calibration curve. The voltage is converted into data values in the form of digital numbers by a standalone wireless battery powered electronic circuit after each measurement see . The meaThe potassium ion selective electrode had been conditioned before use in a 0.5 mmol/L KCl  aqueous solution for 1 h. The calibration of the system was performed using KCl solutions with a concentration in the range between 1 mg/L and 10 g/L with addition of urea in the concentrations of 0%, 0.5%, 1%, 1.5% and 2% . All so2.2.The activity monitor is based on determination of skin perspiration rates during daily activities. Sweating depends on the effort expended in activities. Humidity close to the skin increases with the effort of the person and ambient conditions. It is necessary to have two humidity and two temperature sensors with a certain distance between them and the skin in measurements to calculate perspiration rate.2/h), calculated with a well-known mathematical model [S·(dm/dt) is the evaporation rate (g/m2/h), D′ is the constant 0.67 × 10−3 (g/m/h·Pa), (∂p/∂x) is the vapor pressure gradient in (Pa/m). From this equation, we can calculate the rate of sweat evaporation close to the skin surface and then interpolate the total amount of evaporated water as the result of integration over time.The water transport through the skin, the so called transepidermal water loss  was used for temperature stabilization of the anodization process. Millipore water was used for the preparation of electrolytes and sample washing. Anodization of aluminum and titanium layers was performed in a 0.9 M aqueous solution of oxalic acid in the galvanic static mode with the current density of 4 mA/cm2 and the voltage of 30 V on stationary stage of porous alumina growing. When the anodization front reached the titanium underlayer and all aluminum was fully consumed, the anodization voltage began to increase and its growth continued up to a certain limited value at 37 V. Then the anodizing mode was automatically switched to the constant voltage mode for electrochemical anodization of titanium underlayer to continue. The titanium anodization process took about 40 min. After reaching the constant minimum value of anode current (less than 50 μA/cm2) [The nanostructured TiO μA/cm2)  the proc3, 35 mL/L H3PO4 solution kept at 65 °C for 15 min thus opening the array of titanium oxide nanopillars. A photoresist mask for the formation of gold electrodes that provide electrical contact to the sensor structure was prepared by photolithographic techniques on the surface of Ti/TiO2 layer. The mask was made in the form of an inter-digital structure with an electrode width of 100 microns and spacing of 50 microns  close to the skin surface at a distance of 5–7 mm (skin RH sensor). The second commercial resistive humidity sensor HS-15P is located on the opposite side of the sensing unit. This sensor was intended to measure ambient relative humidity (ambient RH sensor). The DS18B20U sensor with digital output has been used for skin temperature measurements. All components of the sensing unit are integrated in the box, which can be fixed on the arm of the person  with an operation voltage between 15 and 25 keV. X-ray diffraction (XRD) analysis was performed at the Department of Condensed Matter Physics  using a laboratory assembled diffractometer equipped with Cu X-ray tube, Siemens high voltage generator, Soller slit, graphite monochromator, and a Radicon scintillation detector. Before analysis, all samples were washed in flowing Millipore water for a few minutes three times and then dried in a stream of warm air.The surface and cross section morphology of the nanostructured TiO2 (RH of 33%), K2CO3 (RH of 43%), Mg(NO3)2 (RH of 57%), NaCl (RH of 75%), KCl (RH of 85%), and K2SO4 (RH of 97%) [2 sensors were aged in the atmosphere of 97% RH vapor for 8 h.Relative humidity (RH) measurements of the developed nanostructured sensor were done by using saturated salts solutions providing stable air humidity near the surface. These solutions include: LiCl (relative humidity (RH) of 11%), MgCl of 97%) . The sen2 and commercial HS-15P) by using saturated salt solutions. After the calibration, necessary adjustment of electronics was done because of different impedance values of the new and commercial sensors. Then, the portable part of the system was tested with the help of four volunteers during standard life activity and sport exercises. During testing each volunteer wore the perspiration sensor module on the arm  × 1010 pil/cm2. Each pillar has a smaller lower part diameter and a bigger upper part diameter as seen from cross section image  all crystals were not transformed from the anatase to the rutile phase configuration. The interatomic d-spacing measurements also revealed that the size of the spacing of the main TiO0 nm see . These d3.3.2 sensor were performed in a closed chamber filled with saturated salt solutions in the range of humidity from 11% to 97% according to the methodology described above (Section 2.4). A special electronic module was developed for conversion of sensor impedance value into a voltage signal changing from 3 V to 0 V. The maximum of the signal corresponds to the minimal value of RH data and vice versa the minimum of the voltage signal matches the maximum RH value. The results of RH measurements for fabricated TiO2 sensors are shown in The relative humidity (RH) measurements of TiO2 based sensors are presented in the Responses of three individual TiO2O molecule adsorbed in a vacancy would provide a geometrically particularly well-suited adsorption site for O–H interaction and dissociation. The nanostructured morphology of the sensing layer offers more possibilities for the formation of oxygen vacancies which helps improve the adsorption-desorption process as well. Adsorption of water molecules is going on in a few layers and the growth of a multilayer provides the formation of hydronium ions. Hydronium ion interactions between the absorbed species and the bridging oxygen atoms of the TiO2 sensing layer are expected to facilitate proton transfer with a corresponding increase of electrical conductivity. This process is reversible at room temperature and depends on the humidity level of ambient air, which means that when the humidity level rises a higher concentration of mobile protons increases the electrical conductivity [The sensing mechanism of the semiconducting titanium oxide is based on the adsorption of the surrounding water molecules by the nanomorphology surfaces. Adsorption occurs at exposed fivefold coordinated Ti sites in each case with the hydrogen atoms pointing away from the surface. An Huctivity ,45,46.3.4.2 based and commercial HS-15P, ) was done using saturated salt solutions (see Section 2.4). The calibration results presented in 2-based sensor has a better sensitivity in the higher humidity region and the commercial HS-15P sensor has lower sensitivity balanced in the whole studied humidity range.Before testing the whole wearable system, the calibration of both humidity sensors  were detected during one month after calibration. In the case of the commercial sensor the maximum error was determined to be about 4% RH in the whole range. Calibration constants were determined for the sensors and these values were actualized in the perspiration sensor device.The TiOents see . For ambThe measured current consumption of the perspiration sensor module is shown in 2 skin sensor, the red line corresponds to data obtained from the commercial ambient sensor and the green line corresponds to the water loss calculation.A typical measurement water loss diagram for a male volunteer during an 8-h period can be seen in 2 skin surfaces showed losses of 740 mL of fluids by body perspiration for the 8-h testing time. The skin surface area can be set in the system software according to the age, gender and physical features of the person.Both sensors (skin and ambient) show a high RH value for the male volunteer  during tThe female volunteer  had an aThe analysis of water loss figures showed some influence of the ambient RH sensor from the volunteer sweating during long sport activities. It depends on the distance between the ambient and skin sensors, which is 1.5 cm. However, during long perspiration periods the relative humidity level of the ambient air on the distance of about 2–3 cm around human body can increase. It can be seen from the values of ambient sensor , stationary computer or hospital server, and sent through any network to medical specialists for monitoring and analysis of water balance (metabolism) of the organism.2 layer consists mostly of a crystalline rutile phase, constructed to ensure fast adsorption—desorption process of water molecules. Based on electrochemical technology, as well as with the use of microelectronic methods, a prototype of the planar relative humidity sensor has been designed and manufactured. The conversion from impedance to the voltage signal of sensor response has linear characteristics with a low response time in the range of relative humidity from 33% to 97%.A special designed nanostructured titanium oxide sensing layer, fabricated by anodization techniques, was used for measurements of relative humidity level near the human skin surface. The semiconducting TiOThe obtained results are promising for further applications in different fields such as fitness, medical or military services and the fabricated system has a low cost and high efficiency.


Tunable band-stop filters based on graphene with periodically modulated chemical potentials are proposed. Periodic graphene can be considered as a plasmonic crystal. Its energy band diagram is analyzed, which clearly shows a blue shift of the forbidden band with increasing chemical potential. Structural design and optimization are performed by an effective-index-based transfer matrix method, which is confirmed by numerical simulations. The center frequency of the filter can be tuned in a range from 37 to 53 THz based on the electrical tunability of graphene, while the modulation depth (−26 dB) and the bandwidth (3.1 THz) of the filter remain unchanged. Specifically, the bandwidth and modulation depth of the filters can be flexibly preset by adjusting the chemical potential ratio and the period number. The length of the filter (~750 nm) is only 1/9 of the operating wavelength in vacuum, which makes the filter a good choice for compact on-chip applications. Graphene, a monolayer of carbon atoms arranged in a two-dimensional honeycomb lattice, has attracted much attentions in recent years for its constant light absorption13479919202223252728Plasmonic filters are essential for information processing systems and have been widely investigated3031323331et al. proposed a wavelength selector by coupling a graphene ribbon with a graphene disket al. proposed to place a uniformly doped graphene monolayer on a silicon gratinget al. proposed a free-standing periodically-stacked graphene nanoribbon waveguide with patterned chemical potentialBand-stop filters that selectively eliminate undesired information and suppress interfering signals, play an important role in broadband communications and information storageIn this report, we propose a type of tunable band-stop filters based on graphene monolayers with periodically modulated chemical potential that can be treated as graphene plasmonic crystals (GPCs). Investigating the energy band diagram of the GPC, one can find a blue shift of the forbidden band with increasing chemical potential. An effective-index-based transfer matrix method (EIB-TMM) is adopted to calculate the transmission and optimize the design of the GPC filter, which are in good agreement with our numerical simulations. Such a method can greatly promote the efficiency of calculations. The center frequency of the filter can be tuned from 37 to 53 THz with a stable modulation depth as high as −26 dB and a fixed bandwidth (3.1 THz) based on the electrical tunability of graphene. Bandwidth and modulation depth can be preset freely by adjusting the chemical potential ratio and the period number. The length of the filter is only 750 nm, just 1/9 of the operating wavelength in vacuum, which makes it a very good candidate for integrated plasmonic devices.The dispersion relation of the GPs in a graphene sheet can be described as the quasi-static form41σg is the complex surface conductivity of the graphene monolayer, εeff is the effective environment permittivity and neff = β/k0 is the effective refractive index for the GP mode which is inversely proportional to σg.where σg of a graphene monolayer is described by the Kubo formulation42σg = σintra + σinter, where σintra corresponds to the intraband electron-phonon scatteringIn the THz frequency region, the complex surface conductivity σinter is given byand the interband transition contribution e is the elementary charge, kB is Boltzmann’s constant, T is the ambient temperature, ħ is the reduced Planck constant, ω is the photon frequency, n and vf are the charge density and the Femi velocity of the graphene respectively, and μ of graphene on a silica substrate could reach 40000 cm2V−1s−1 at room temperature2V−1s−1. To improve the credibility of the calculation results, 10000 cm2V−1s−1 is adopted as the carrier mobility in our studyHere μc is the only variable of neff for a specific GP mode. A graphene monolayer with a periodic μc acts as a GPC. When broadband GPs, which can be excited by tip scattering couplingd1 and d2 have different chemical potentials under a backgate bias voltage. The silica layer not only couples with the graphene but also ensures the tuning feasibility of the chemical potential of graphene. When a gate voltage is applied to the device, the charge density of the graphene is inversely proportional to the thickness of the silica layer d asεd is the permittivity of silica. Thus the chemical potential ratio r = μc2/μc1 between two regions is equal to d2 is fixed at 130 nm and r is regulated by d1. The permittivity of silica is assumed as 3.9 and the period of the GPC is D = 2w = 50 nm. It is worth emphasizing that the influence of the silicon grating on the GPs could be eliminated since the thickness of the silica layer is always larger than 100 nm.According to r = 1.25. Bloch wave vector reaches a maximum on both edges of the forbidden band and decreases as frequencies are away from the forbidden band. As shown in μc1. Larger μc1 causes wider bandwidths for the allowed and the forbidden bands. In particular, high-order forbidden bands appear when μc1 is small enough.By using the characteristic equation (see methods), we can calculate the forbidden band of the GPC as shown in N can be described as4546The EIB-TMM is adopted to calculate the transmission and optimize the design of the GPC filters. When the GPs propagate along the graphene, reflection and transmission will occur at each interface. As an analogy of a one dimensional photonic crystal, the transfer matrix of the GPC with a period number δj = k0neff,jw and j = 1, 2). The transmission of the GPs is47where where N = 15 are shown in μc1 increases from 0.3 to 0.6 eV, the center frequency experiences a blue shift from 37 to 53 THz, showing a 16 THz tunability range. Particularly, the modulation depth and the bandwidth in the tuning process remain approximately stable around −26 dB and 3.1 THz, respectively. The flexible tunability, stable modulation depth and bandwidth greatly enhance the application potential of such band-stop filters. We notice that a high-order stop band appears in the transmission spectrum when μc1 is 0.3 eV, which is attributed to the high-order forbidden band of the GPC mentioned above.Transmission spectra with the same parameters as in E|2) distributions (side view) at the pass band and the stop band frequencies of the filter with μc1 = 0.4 eV are shown in Near-field intensity .


This research is the first empirical attempt to calculate the various components of the hidden bias associated with the sampling strategies routinely-used in human genetics, with special reference to surname-based strategies. We reconstructed surname distributions of 26 Italian communities with different demographic features across the last six centuries (years 1447–2001). The degree of overlapping between "reference founding core" distributions and the distributions obtained from sampling the present day communities by probabilistic and selective methods was quantified under different conditions and models. When taking into account only one individual per surname (low kinship model), the average discrepancy was 59.5%, with a peak of 84% by random sampling. When multiple individuals per surname were considered (high kinship model), the discrepancy decreased by 8–30% at the cost of a larger variance. Criteria aimed at maximizing locally-spread patrilineages and long-term residency appeared to be affected by recent gene flows much more than expected. Selection of the more frequent family names following low kinship criteria proved to be a suitable approach only for historically stable communities. In any other case true random sampling, despite its high variance, did not return more biased estimates than other selective methods. Our results indicate that the sampling of individuals bearing historically documented surnames (founders' method) should be applied, especially when studying the male-specific genome, to prevent an over-stratification of ancient and recent genetic components that heavily biases inferences and statistics. The question of how representative is a sample of a given population is particularly critical in human genetic research, where data collection is strongly affected by ethical and social factors. The choice of the sampling strategy can affect the estimation of a number of relevant parameters and, accordingly, the inferences one can make about either the groups or the genetic variants under study. The ideal goal is to achieve the best compromise among recruitment costs, statistical power and representativeness. To make a sample an unbiased proxy of the underlying population, either for genetic screening, genotype-phenotype association studies or evolutionary reconstructions, its composition should minimize close kinship, ambiguous individual ancestry assignments, and the side effects of population stratification.Most of present-day human populations have experienced recent admixture to some extent  and geneUsing surnames to select research subjects has the advantage that family names are cultural markers typically transmitted from fathers to sons in most human societies. The distributions and mode of inheritance of surnames mirror the non-recombinant markers of the male specific regions of the Y chromosome (MSY). The main difference between surnames and MSY sequences is the nature of the transmitted units which are predominantly, if not exclusively, identical by descent for MSY markers and identical by state (polyphyly) other than by descent (monophyly) for surnames. In addition, the depth of the genealogical reconstruction is largely unbounded for MSY markers, while for surnames it is limited to the time since such family names have been stabilized as markers of inheritance (around 1200–1800 AD in Western societies). Such differences have been invoked to explain deviations from neutral expectations when surnames were used to estimate consanguinity or gene propagation , 10. NonA number of reasons makes the Italian population an ideal case-study for surnames-related research: Italians show one of the highest surname diversity in the world  with a mThe present work aims at first comparing different surname-based sampling strategies, to estimate the bias associated with each method. In order to do this, we reconstructed the surname distributions of 26 Italian communities with different demography in the time interval encompassing the 1447–2001 AD. The degree of overlapping between “reference core” surname distributions, obtained from analyzing the oldest historical frames, and the distributions obtained from sampling present-day surnames by probabilistic (random) and selective  methods was quantified at different geographic scales . Whenever possible, jackknife re-sampling and comparisons between different data sources and models, with low and high levels of kinship, were applied to weigh the various sources of the sampling bias.Twenty-six Italian communities belonging to 11 provinces and 8 regions were analyzed : four ofStato delle anime), baptismal , and marriage  sacramental registers. The present-day distributions of surnames from the same communities were extracted from the digitalized versions of the 1993 complete national phone directory [We reconstructed the earlier distributions of surnames from either three kinds of historical records: census , single-digit mismatches (i.e. “Marino/Marini”) and double surnames (i.e. “Albertini Marchesani = Albertini”). In presence of doubtful cases, a stringent criterium was adopted in order to minimize the bias due to mutational events . Overall, such a method tends to inflate the degree of overlapping between “founding” and present-day distributions and, hence, to underestimate the sampling bias. The lemmatization process was applied separately to each community. The complete database is provided in In order to validate the use of different sources, as either historical or recent references, we recovered and compared the surname distributions from SEAT and ISTAT records in the community of Cerchio , as well the surname distributions from marriage and baptismal acts in the community of Montecarlo .x is the number of the k surnames which are in common between the historical and current repository and Nk is the size of the current repository. SDB ranges from 1, no surname shared, to 0, all the surnames of the current repository are shared with the historical repository. A “low-kinship” (LK) model, namely when only one individual per surname was considered, and a “high-kinship” model (HK), when using the entire set of surnames and their bearers, were applied to each pairwise comparison. Under HK, k was intended as the total number of surnames, allowing multiple counts for the same type; under LK, k was intended as the number of different surnames, one for type. Being our null hypothesis the adhesion of the sampled surnames to the oldest surname distribution of each community, as occurs when collecting according to the founding surnames method, the SDB rate expectation is zero under both models.For each strategy we measured the sampling-dependent bias (SDB) according to the formula:To estimate how far the departures of SDB from zero are exclusively due to genetic drift we simulated the evolution of the 26 studied communities under both a growth (observed relative growth rates) and a stationary model (null growth rate) by the Markov chain Monte Carlo method implemented in the software ASHEs , 17. ForTo estimate how far SDB is affected by sample size, we performed a total of 201 jackknife re-samplings of twenty, fifty and, when possible, one hundred individuals out of every dataset, using PopTools version 3.2.5 .STATISTICA v. 6.0  and XLSTAT (Addinsoft) were utilized to perform the Chi-square tests, the correlation analyses and to create graphics.When simulating by the random sampling criterion (R), the entire list of surnames of the recent repository (SEAT or ISTAT) was considered as starting set. When selecting samples by a spatial distribution criterion , we chose only those surnames whose geographic origin was unambiguously centered within a single province (the metropolises Milan and Rome excluded), as shown in the SEAT 1993-derived GENS database [2 = 0.87, P<0.01 and R2 = 0.82, P<0.01 respectively) and did not differ significantly . The fact that Cerchio and Montecarlo are communities with intermediate size and growth rate would suggest that, for most of the investigated communities, the availability of data sources exerted a negligible effect on the estimate of the intrinsic bias (SDB).Bivariate analyses of present-day surname lists obtained from ISTAT (2001) and SEAT (1993) records in the community of Cerchio  and of “As a rule, the comparisons between “founder” and present-day lists of surnames showed a low level of concordance independently of the applied sampling strategy and the kinship model . RegardiThe percentage of shared surnames sampled with a random strategy (R) was predictably low under a LK model  as well as under a HK model . Instead, it was somewhat surprising to observe the same features when applying the grandparents’ criterion (GP): surnames sharing ranged from 3 to 47% (SDB = 0.53–0.97) under the LK and from 6 to 95% (SDB = 0.05–0.94) under the HK.The frequency-based criterion (FQ) showed the highest degree of uncertainty: surnames sharing, in fact, ranged from 4 to 100% (SDB = 0.00–0.96) under both the LK and the HK. The criterion based on locally-spread surnames (LS), on the other hand, showed the lowest bias: the overlapping degree varying from 22 to 65% under the LK (SDB = 0.35–0.78) and from 41 to 86% under the HK (SDB = 0.14–0.59). In this case preserved patrilineages approach the estimated proportion of “autochthony” of Italian surnames at the province level  and theSimulations performed under growth and stationary models allowed us to measure the expected bias accumulated by lineage sorting alone (genetic drift), from foundation to present times. As shown in A more accurate analysis was done by evaluating the dependence of SDB by the type of the community –S6 Figs.t) > 500 . Similarly, we found that the higher the difference between the intrinsic bias calculated under the HK and LK methods (ΔSDB), the lower the value of S/N in the “founding” list, here used as a crude estimate of early population diversity [2 = 0.35, P = 0.02), the FQ  and the GP  sampling strategies but not for the LS criterion . The same tendency was observed between ΔSDB and isonymy, here intended as the random component of inbreeding  (data not shown). Interestingly, Nonantola , despite being not geographically isolated and with a size in the order of thousands, showed the highest ΔSDB when sampling by the FQ criterion. In this case, the retention of frequency-based surname legacies is more easily explained by its hosting a “Partecipanza”, a social-economic entity where rights over common lands have been long transmitted strictly following residency and patrilineal genealogies [A second observation is the generally lower SDB values scored using HK compared to LK sampling criteria, with a more pronounced trend in small communities. The drop of SDB was significantly lower in communities with present-day size  and, vice versa, overestimates SDB in regions represented by large open cities (Apulia). Missing or overabundance of data prevented us to extend the analysis to higher levels than municipality, respectively for the GP and LS method. Nonetheless, a breakdown of SDB is expected when locally spread surnames are assigned at the regional and, of course, at the Country level.When the sampling bias was calculated at the level of mid (region) and macro (Country) area, the overall patterns observed at the municipality level held for the R and FQ sampling methods under both the LK and HK models (data not shown). Deviations are mainly due to the proportion of closed The mean values of the percentage of “founder” surnames (1-SDB), calculated after randomly re-sampling twenty, fifty and one hundred individuals out of the complete list of present-day surnames, were not appreciably different under the LK  and HK  models. However, the range of values decreased geometrically by increasing the sample size.The outputs of random Jackknife resampling for the S/N parameter are shown in The identification of the most reliable sampling strategy, among the many available for human genetic studies, could be of great utility. Conversely, an improper collection of samples from the population may introduce hidden confounding factors. With this perspective, we calculated the various sources of bias associated with common methods of sample recruitment: those employing family names as ancestry markers. Sampling by surnames is in fact one of the most accurate and cost-efficient ways to assess the genetic composition of historical populations, despite the fact that family names behave as a single locus transmitted along only one parental lineage, and the fact that mismatches are expected in Y-DNAs due to illegitimate paternities and adoptions .A main result of our analyses is that the fidelity to the ancestral composition of the population (measured from 1447–1775) by samples selected from current lists of surnames is variable but generally low whatever is the size of the sample, the selection strategy, the primary source of data, the geographic scale, or type of the community. As expected, lineage sorting accounts for the deviations from fidelity only partially and in very closed communities.Despite the use of a relaxed lemmatization, biases lower than 40%, intending this term as the complement to one of the degree of overlapping between “founding” and present-day lists of family names (SDB), have been observed only in small mountainous hamlets as far as a close parenthood among participants was admitted (high-kinship model). The selection of unrelated donors is usually associated with a substantial increase of the bias other than to higher costs of recruitment and, in remote areas, a lower sample size. Low kinship in most cases means rates of bias much higher than 50%, unless the first quartile method is applied in stable communities where cultural  or geographic (mountain terrain) barriers preserved family names with high frequency over long periods of time.Population stratification due to recent fluctuations in allele frequencies over time thus appears a foremost level of apportionment of the overall genetic variance. While typically not recognized because of the lack of contribution of bio-demographic data to genetic sampling designs, the diachronic variance would play a crucial role in the representativeness of a population sample and, hence, to its utility in biological research.The proportion of ancestry from ancient and recent demography can vary widely between individuals, leading to step-ups of the internal structure of the population which, in turn, may easily introduce either spurious results (type I and II errors) in genetic association studies or distortions in historical and evolutionary reconstructions. The latter case has been demonstrated by Manni et al.  who founHere, we demonstrated that sampling criteria could easily affect population parameters resulting in inflated (random methods) or deflated (selective methods) estimates of diversity.The most efficient method to correct population parameters for the diachronic bias is to select individuals bearing historically documented surnames (“founders” method). Alternative but equally time-demanding methods, such as those based on surname distribution (LS) and residency (GP), are heavily influenced by recent gene flows and appeared to be efficient only in specific contexts, as macro geographic scales and alpine villages. Moreover, they generally result in a reduction of the maximum gatherable sample size down to a hundred or even less. Consequently, their use in population genetics is limited by the poor statistical power, and is very limited or impracticable in genotype-phenotype association studies. In these latter cases a truly random sampling under a HK model, despite it carrying a high SDB, is able to give samples of suitable size at affordable costs.Among the various features used to define a human community both geographically and demographically, altitude was found the best proxy of the bias inherent to most of the sampling procedures in the modern Italian population.We can conclude that sampling individuals bearing historically documented surnames should be the method of choice to buffer the stratification of ancient and recent genetic components of the sampled population. Nonetheless, the selection of “founders”, while excluding misleading results from markers of the male specific fraction of the Y chromosome, does not prevent that recent population reshufflings heavily driven by women mobility could bias inferences and statistics based on the variability at autosomal, X-chromosome and mitochondrial markers.S1 Fig(TIF)Click here for additional data file.S2 FigYellow lines, simulated SDB values with population growth; yellow diamonds, simulated SDB values with constant population size.(TIF)Click here for additional data file.S3 FigHK, high-kinship model; LK, low-kinship model.(TIF)Click here for additional data file.S4 FigHK, high-kinship model; LK, low-kinship model.(TIF)Click here for additional data file.S5 FigHK, high-kinship model; LK, low-kinship model.(TIF)Click here for additional data file.S6 FigHK, high-kinship model; LK, low-kinship model.(TIF)Click here for additional data file.S7 Fig(TIF)Click here for additional data file.S8 Fig(TIF)Click here for additional data file.S9 Fig(TIF)Click here for additional data file.S1 Dataset(XLSX)Click here for additional data file.


International donors have increasingly shifted AIDS funding directly to community-based organizations (CBOs) with the assumption that responding to the epidemic is best achieved at the community level. The World Bank, ICF Macro, and the National Council for Population and Development in Kenya, conducted a study to evaluate the community response in Kenya. The study used a quasi-experimental design comparing seven study communities and seven comparison communities in Nyanza Province and Western Province. We examined the impact of CBO activity on individual and community-level outcomes, including HIV knowledge, awareness and perceptions, sexual risk behavior, and social transformation . The study consisted of two components: a household survey conducted in all 14 communities, and qualitative data collected in a subset of communities. Individuals in communities with higher CBO engagement were significantly more likely to have reported consistent condom use. Higher CBO engagement was associated with some measures of social capital, including participation in local and national elections, and participation in electoral campaigns. CBOs provide added value in addressing the HIV and AIDS epidemic in very targeted and specific ways that are closely tied to the services they provide ; thus, increasing CBO engagement can be an effective measure in scaling up prevention efforts in those areas. At the pandemic . CBOs arpandemic . Over thpandemic .The increased role of CBOs fighting AIDS was supported by the assumption that controlling and responding to the epidemic is best achieved through the active involvement of communities. Theoretical literature on CBOs has argued that they are well positioned to reach the previously missed elements of the society and tackle disease and poverty at their roots . In addiEmpirical literature has shown that community-based interventions in Kenya have the potential to decrease the stigma associated with HIV/AIDS , improveTo address this evidence gap, the World Bank commissioned a rigorous evaluation of the community response to HIV and AIDS in Kenya from January through September 2010. The evaluation addressed three primary research questions: Do community members in communities with stronger CBO engagement demonstrate (1) a significant difference in their access to and use of HIV and AIDS services; (2) a significant difference in knowledge, attitudes, perceptions, and behavior related to HIV and AIDS; and (3) a significant difference with respect to social transformation indicators compared to communities demonstrating weaker engagement?Recent surveys estimate the prevalence of HIV in the adult population in Kenya to be between 6.3% and 7.4% . The geoCBOs have been at the forefront of the fight against AIDS in Kenya. Their involvement was identified as a key component of the national response  and six districts Kisumu, Nyando, Kisii, Nyamira (Nyanza Province) and Butere-Mumias and Vihiga (Western Province) were included in the evaluation. A power analysis concluded that there would be 80% power to detect a medium effect size difference in 14 communities with a total of 192 households per community. Nyanza and Western provinces were selected for inclusion based on high HIV prevalence. The six districts have similar demographic characteristics, but varying levels of CBO activity. Selection of the communities occurred through several steps. First, the two provinces, Nyanza and Western, were selected for inclusion in the study based on high HIV prevalence. Within each province, the six districts that were selected were relatively close to one another and had relatively similar demographic characteristics, but were known to have varying levels of CBO activity. Within each district, a list of communities was delineated from the Kenya National Bureau of Statistics database. From this list, a random sample of 34 communities was selected. Communities in the random sample were assessed using specified criteria  in the community and individual awareness of CBO activity in the community.We used a database of CBOs maintained by the National AIDS Control Council (NACC) and information provided by local experts to capture the number of CBOs in each community. Given the potential that the NACC's CBO information was incomplete, and recognizing that the strength of the CBO activity may be determined by factors other than the number of CBOs, we used data collected from the household survey to provide additional information about the CBO reach, and to verify our initial study-comparison assignment. In the statistical analyses described below, the level of CBO engagement from the survey data was measured by the proportion of respondents who were aware of HIV/AIDS-related CBOs in their community. Communities with higher than the median proportion (46.9%) of respondents aware of services provided by CBOs were considered study communities, and communities with lower proportions of respondents aware of services provided by CBOs were considered comparison communities. Community assignment is not considered an absolute “high” versus “low,” but is rather a relative comparison of “higher” versus “lower” community engagement. A total of five communities were reclassified from the original assignment based on these post hoc criteria. Communities 9, 10, and 13 were reassigned from study to comparison, and communities 11 and 12 were reassigned from comparison to study. The final list of community assignment and their characteristics are presented in A sample of 2715 households was randomly selected using official data for household populations from the list of National Sample Surveys and Evaluation Programme clusters, created and maintained by the Kenya National Bureau of Statistics (KNBS). In each household, up to three individual adult respondents were interviewed, resulting in a total of 4378 individuals. The household respondents were chosen based on selecting the head of household (if home at the time the interviewer went to the door), and the spouse of the household head (if existing and home). If the head of the household was not home, the interviewer talked with adults in the household and asked for nominations of up to three individuals. The head of household was asked to select other adult(s) to participate to reach up to three respondents. The Household Survey was administered to one individual per household, which included items assessing household-level constructs . An individual questionnaire was administered to each individual respondent, which included individual-level constructs . The survey was fielded from May to June 2010.Service awareness and utilization was included in the individual survey and was measured using Yes-No questions whether the respondent was aware of (awareness questions) and used (utilization questions) services in the following categories: (1) prevention, (2) treatment, (3) care and support, (4) impact alleviation, and (5) community mobilization. The responses were coded as 1 if the respondent responded “Yes” and 0 otherwise.Knowledge indicators reflected the UNGASS reporting system, and focused on the knowledge of HIV transmission modes, medications, and prevention. The individual survey included the following questions : People reduce HIV chances by having one uninfected partner; People reduce chances of getting HIV by using a condom; People CANNOT get the HIV virus from a mosquito or insect bite; People cannot get HIV by sharing utensils with a person who has AIDS; It is possible for a healthy-looking person to have HIV. Correct responses were coded as 1 and incorrect (including “Don't Know”) as 0. In addition, respondents were asked the following Yes-No questions: Are there any special drugs that a doctor or a nurse can give to a woman infected with the HIV virus to reduce the risk of transmission to the baby? Have you ever heard of VCT? Would you accept VCT if a volunteer came to the house? Do you know of drugs to control HIV? The responses were coded as 1 if the respondent responded “Yes” and 0 otherwise. We analyzed each knowledge item separately because individual items measure different aspects of HIV- related knowledge . This mode of analysis provides a more nuanced assessment of the association between the community engagement and knowledge than using a single knowledge scale.Behavior was measured using two indicators. – consistent condom use with all partners in the past 12 months and ever having had an HIV test . Individuals were asked the number of sexual partners in the past 12 months, and for each partner, were asked, “Was a condom used every time you had sexual intercourse with that partner in the past 12 months?,” with response options Yes-No. Those who responded “Yes” to each partner were considered consistent condom users (coded “1”) and those who responded “No” to the question for any partner were not considered consistent condom users and coded “0”. Individuals were asked if they ever had an HIV test (response options Yes-No).Social transformation was assessed using measures from the social science and public health literature focusing on social capital and gender norms. Social capital indicators were taken from the Adapted Social Capital Assessment Tool (A-SCAT) ((A-SCAT) . Social Cognitive social capital was measured with a 20-item scale with items indicating perceived strength and cohesion of the community such as, “My neighbors would help me in an emergency; if someone in the community lost their job, there are community members who would help them with money or other resources.” Response categories included “Strongly Disagree, Disagree, Agree, and Strongly Agree.” A mean and summative scale was created and analyzed as separate outcomes. A scale of attitudes toward one's own children was measured using six items (Yes-No response): “Do you help your children to understand that they have their rights; Do you help your children to understand that their rights are legitimate and nobody can violate them; Do you help your children to react against the violation of their rights; Do you discuss with your children when others’ rights are violated; Do you encourage your children to react against violation of others’ rights; and Do you allow your children to participate in decision-making in the family?” “Yes” responses were coded “1,” and “No” responses were coded “0.” An average score across all items was calculated.gender norms were based on surveys developed by the Kenya Diffusion and Ideational Change Project and the Malawi Diffusion and Ideational Change Project , using Mplus . MultileBivariate differences in demographic factors between study and comparison communities resulting from post hoc reassignment of communities were found for HIV prevalence, rural versus urban characters, employment, age, and marital status . These dIn addition to those factors, we also controlled for education as this variable is typically associated with HIV knowledge and behavior. For binomial outcomes, logistic regression was performed, and results are reported as odds ratios with confidence intervals. For continuous outcomes, linear regression was performed, and results are reported as coefficients with standard errors and p-values.In-depth semi-structured interviews with 28 CBOs and 58 key informants (KIs) were conducted in a sub-sample of eight communities. The interviews provided more detailed information on CBO services and activities, and data on social transformation and contextual factors that facilitate and constrain the effectiveness of HIV activities and programs. Participating CBOs were identified based on the NACC database of CBOs and supplemented by information provided by the NACC staff and local community experts. KIs included (1) the director of the Constituency AIDS Control Committee  in each community, (2) a local government leader, (3) the head nurse from the largest local clinic, (4) a senior clergy person from the largest religious congregation, and (5) the principal of the largest school.The interviews with CBO staff focused on the activities of CBOs, their targets/audiences, geographic reach, and staff and volunteers involved. Questions included the following: ‘When was the organization established? What did the response to the HIV/AIDS epidemic look like before your organization was established? What activities did your organization focus on initially? How has the scope of activities changed over time? What goals have you achieved in your community? What are some of the factors that have helped you achieving your goals? How do you think your work has affected the way women/orphans/people with HIV are treated? What is your experience with the local government response to HIV/AIDS? How does your organization interact with government? How does your organization interact with other local organizations?’ The interviews with KIs provided information about social capital and transformation in the community, and the perceived role of CBOs in affecting those factors. Questions included “Over the past five years what changes have you observed in how people trust each other/voting behavior/participation in voluntary organizations/collective action/the ability of women to make economic decisions/girls’ access to education/violence against women/how people with HIV are treated? What factors do you think caused any changes?”Trained interviewers conducted the interviews in the local language, and took detailed notes, and in some cases, recorded, and transcribed the interviews. Notes and transcription were translated into English. Interviews were reviewed and coded by a team of two individuals. Initial codes were developed to match the interview topics, and additional codes were added during the review and coding process as needed.Significant associations found between the key independent variables – higher (coded “1”) or lower (coded “0”) CBO engagement – and measures of HIV knowledge, attitudes, perceptions, behavior, service utilization, and social transformation are in bold in the tables.In addition, respondents in the study group had four times higher odds of reporting consistent condom use with all sex partners in the last 12 months , and were more likely to have ever had an HIV test .We found no statistically significant association between the strength of CBO engagement and service utilization.Strength of CBO engagement was not associated with cognitive social capital or any indicators of gender norms.The average length of time a CBO was present in the community ranged between 5.5 and 8.8 years. The average number of volunteers in the past year ranged from 4 to 26. The average number of CBO clients reported in a community varied widely, and ranged from 67 to 853.CBOs were engaged in similar activities across study and comparison communities. In all eight communities, CBOs engaged in prevention activities, support for PLWHA, activities targeting OVC, and information and education activities aimed at increasing the awareness and knowledge of HIV and AIDS. In seven communities, CBOs also engaged in care; in five communities, in advocacy efforts; and in three communities, in impact mitigation. CBOs engaged in provision of medical services in only one community. In six communities, CBO leaders mentioned behavior change communication as part of their organization's mission, and in three communities, CBOs distributed condoms. The number of the clients reached as a percentage of the overall population was the most pronounced difference between the study and the comparison communities .The interviews provided historical depth to the quantitative survey and insight into how social capital, gender relations, and stigma and discrimination have changed over time. Furthermore, the interviews with KIs were designed to help determine the extent to which any observed differences in outcomes between study and comparison communities could be attributed to the activities of local CBOs.Voting, an indicator of social capital in terms of civic engagement, was reported by KIs to have increased in all communities – they noted that turnouts in national and local elections have increased over the past five years. Most attributed the increase to rising education levels and higher awareness of political and voting rights among community members. They did not, however, identify what caused the shifts in education and awareness, and none explicitly mentioned CBO activity as the cause of those changes. While KIs did not identify CBOs as a driving force behind increased voting behavior, survey data showed that this indicator was significantly higher in higher engagement communities.In all communities, most of the KIs noted increases in participation in voluntary organizations within the past five years. Self-help groups and groups engaging in income-generating activities, such as setting up fishing ponds or communal poultry-raising, were mentioned as the most common forms of organizations emerging in the research communities. In one community, KIs noted that people formed neighborhood associations assisting families in organizing and financing funerals. The fact that individuals from both study and comparison communities noted increased participation in organizations supports the lack of differences found in this measure of social capital by the household survey.In three communities, increases in participation were attributed to normative changes, although no agents driving the normative change were identified. In one community, CBOs were explicitly mentioned as the source of change. KIs noted that the CBOs in the community have “sensitized people on the importance of coming together.” In the same community, two other KIs attributed the recent changes to increase in government assistance given to voluntary associations. In one community, increases in the number of voluntary organizations and in the number of community members belonging to such organizations were attributed to the local leadership's support of such initiatives.In three communities, KIs reported an increase in economic opportunities available to women. In two communities, the KIs said that women were gaining more influence over how to spend the household money. In one community, some KIs attributed this to activities of self-help groups engaging in income-generating activities.In addition, respondents noted structural factors such as women being more aware of their rights, general increases in the level of education among women in Kenya, and migration .Across all communities, KIs noted increases in the number of girls enrolled in elementary schools. They attributed the main drivers of the increases in female enrollment in education and also perceived declines in violence against women to shifts in national policies, rather than CBO activity. KIs credited the CBOs with helping to offset some of the expenses related to education, such as paying for school uniforms or providing financial support for orphans to prevent them from dropping out. With respect to women's economic agency and their influence over household finances, KIs in two communities mentioned income-generating activities carried out by CBOs as increasing women's access to money, but not necessarily in increasing their influence on how to spend it.When asked explicitly about the impact of the CBOs on gender relations in their communities, KIs credited the CBOs with helping to offset some of the expenses related toeducation, suchaspaying for school uniforms or providing financial support for orphans to prevent them from dropping out. With respect to violence against women, KIs in all communities mentioned that CBOs educated women about their rights. In one community, one KI noted that a CBO also provided legal representation for victims of violence. The interviews, however, suggest that those activities hadalimited impactand wereofsecondary importance compared to the changes in national policies.The qualitative data regarding gender roles support the findings from the survey, in that there were no statistically significant differences between the study and comparison communities in measures of gender norms in the survey. This is consistent with perceptions of the KIs that changes gender norms have occurred across the country as a result of national policies, rather than CBO activity.The objective of this evaluation to assess, using a scientifically rigorous methodology, whether CBOs providing HIV and AIDS prevention and treatment activities add value to the government response to the epidemic and have a measurable impact on individual and community-level outcomes. While the study did not assess changes in HIV incidence or prevalence, it was able to identify how higher CBO engagement and activity affects some aspects of knowledge and behavior that partially drive the epidemic.People in communities where a high proportion of individuals were aware of CBO activity showed greater knowledge of some HIV transmission and prevention methods, were more likely to use condoms consistently, and ever have been tested for HIV, demonstrated greater likelihood to engage in community mobilization activities, including voting and participating in electoral campaigns. While CBOs provided similar services across the study and comparison communities, what differentiated communities was the number of community members aware of, and, possibly, reached by these activities. Thus, in communities where CBOs are engaging in prevention efforts, and higher numbers of community members are aware of their work, the levels of knowledge and awareness may be higher, and people may be more likely to engage in lower risk sexual behaviors.The qualitative data provide insight into the larger national effort in Kenya to address the social drivers of the HIV/AIDS epidemic. For example, national policies that have increased access to education seem to have made a significant impact on increasing the rights of women in all communities in the evaluation, regardless of existing CBO activity. It is notable that some key informants viewed CBOs as increasing awareness of policies and laws through outreach and awareness campaigns. Thus, the potential for CBOs to augment national efforts can be viewed as a means of disseminating information from the national to the local level.The study findings are subject to several limitations. First, the lack of data on CBO activities made a priori classification of the community response difficult. To address this limitation, measures of CBO engagement embedded in the household survey served to verify accuracy of a priori group assignments. The community-matching process and controlling, through multivariate analysis, for potentially confounding factors that differed across communities, reduced the likelihood of factors other than CBO engagement driving the associations detected in the analyses.The evaluation was conducted at one point in time, limiting the ability to make causal conclusions about the impact of CBO activity on the outcomes of interest. For example, the fact that individuals in some communities are more aware of CBO services may be the driving force behind, rather than the outcome of, a high level of CBO activity in that community. Similarly, greater awareness and political activism may make it easier for CBOs to establish themselves and be successful in a specific community. While the cross-sectional design does not make it possible to reach causal conclusions, the evaluation was designed with these limitations in mind. Additional evidence from qualitative interviews helped support the conclusions obtained from the quantitative analysis. Our analysis included testing several outcome variables, which may increase the risk of type 1 error. However, it also increases the level of detail and nuance of the overall analysis.We did not conduct sensitivity analysis to assess how the results presented above change if we change the cut-off we used to assign communities to study and comparison communities. The same cut-off for assignment was used in all three components of the study: the household survey, the interviews with the KIs, and the interviews with the CBO staff. This allowed us to show that the CBOs in both groups engaged in similar types of activities  and, from the KI interviews, that the contextual factors across both groups of the communities were roughly the same and the only difference between the study and comparison group was the intensity of exposure to CBO activity. Changing the cut-off point we used in the analysis of the household survey data would require reanalysis of the data from the interviews with CBO staff, to assess whether there were no systematic differences in the types of activities in which the CBOs engaged in the reassigned groups, and reanalysis of the interviews with the KIs, to assess whether there were no systematic differences in contextual factors across the newly assigned study and comparison groups. We consider the multi-method design to be the key strength of our study that allows for triangulation of information across the quantitative and qualitative components. However, it makes sensitivity analysis of a single study component exceptionally challenging. Triangulation from multiple data sources enabled us to distinguish instances in which better HIV/AIDS-related outcomes could be attributed to CBO activities from outcomes that were most likely affected by other factors, including policy changes at the national level. This evaluation suggests that CBOs provide added value in addressing the HIV/AIDS epidemic in targeted and specific ways that are closely tied to the services they provide. Increasing CBO engagement can be an effective measure in scaling up prevention efforts, especially those aimed at improving knowledge and awareness of AIDS in Kenya.


Programmed death ligand 1 (PD-L1) is an immunosuppressive molecule expressed by many cancer types, including a large proportion of head and neck cancers (HNC), and ligation of its receptor, programmed death 1 (PD-1), induces exhaustion of effector T cells. It has been shown that interferon gamma (IFNγ) induces PD-L1 expression in many cancer types including glioblastoma, melanoma, lung and kidney cancer. Importantly, the stimuli and mechanism for PD-L1 upregulation in HNC cells are not well characterized. IFNγ signals through Janus Kinase 1/2 (JAK1/2) heterodimer complex and mediates signal transducer and activator of transcription 1 (STAT1) phosphorylation, leading to type I cytokine expression, upregulation of antigen presentation, and tumor cell recognition by cytolytic T lymphocytes (CTL). We investigated basal PD-L1 expression and the mechanism by which IFNγ signaling upregulates PD-L1 in HNC cells including dependence on JAK/STAT pathway. We observed that IFNγ signaling increased PD-L1 expression in a JAK2 but not JAK1 dependent fashion. In addition, interferon alpha (IFNα), which signals via JAK1/TYK2 did not upregulate PD-L1 expression while still upregulated HLA class I. Specific JAK2 inhibition downregulated NK cell-derived IFNγ induced PD-L1 expression and enhanced cetuximab mediated ADCC. Our data suggest a crucial role for JAK2/STAT1 in IFNγ mediated PD-L1 upregulation. JAK2 inhibition provides a promising strategy to increase tumor cell lysis through maintaining HLA class I while suppressing tumor cell expressed PD-L1 in combination with anti-EGFR cetuximab therapy.


After successful invasion, the intron and HEG are subject to degeneration and sequential loss. It remains unclear whether these mechanisms can fully address the high dynamics and mobility of group I introns. Here, we found that HEGs undergo a fast gain-and-loss turnover comparable with introns in the yeast mitochondrial 21S-rRNA gene, which is unexpected, as the intron and HEG are generally believed to move together as a unit. We further observed extensively mosaic sequences in both the introns and HEGs, and evidence of gene conversion between HEG-containing and HEG-lacking introns. Our findings suggest horizontal transfer and gene conversion can accelerate HEG/intron degeneration and loss, or rescue and propagate HEG/introns, and ultimately result in high HEG/intron turnover rate. Given that up to 25% of the yeast mitochondrial genome is composed of introns and most mitochondrial introns are group I introns, horizontal transfer and gene conversion could have served as an important mechanism in introducing mitochondrial intron diversity, promoting intron mobility and consequently shaping mitochondrial genome architecture.Group I introns are highly dynamic and mobile, featuring extensive presence-absence variation and widespread horizontal transfer. Group I introns can invade intron-lacking alleles via intron homing powered by their own encoded  Group I introns are a special kind of self-splicing ribozyme widely found in protist nuclear ribosomal (r)DNA genes, fungal and plant organellar genomes, bacteria, and viruses  and wideOne powerful mechanism for intron mobility is intron homing, powered by active intron-encoded homing endonuclease gene (HEG) . During Another mechanism of intron invasion is reverse splicing through an RNA intermediate .Saccharomyces complex. We have examined the gain and loss of the HEG only among the intron-containing strains, since no existing theories suggest a high frequency of gains and losses of the HEG within the ω intron, and the turnover rate of HEG within the intron would be expected to be very low compared with that of the mobile intron based on the intron-homing model. To our surprise, we found fast turnover rates of the HEG comparable with those of the well-known mobile intron. We further found extensive mosaic sequences in both the HEG and intron sequences, which is inconsistent with any available mechanisms for group I intron mobility, but suggests recurrent horizontal transfer and gene conversion. This mechanism is believed to play important roles in not only introducing intron sequence diversity but also introducing intron content variation and promoting intron mobility by altering the HEG function during the evolution of group I introns.The yeast mitochondrial 21S large subunit (LSU) rRNA contains a group I intron known as the ω intron . In thisTorulaspora yeast strains from four species were obtained from the National Center of Agricultural Utilization Research  and Dr. Matthew Goddard (The University of Auckland). Genomic DNA of each strain was extracted from overnight cultures following the procedure described in cox2 sequences were also obtained to infer organismal relationships. The GenBank accession numbers for the sequences used in the study are listed in Supporting Information, Table S1, and the primers used for PCR amplification and Sanger sequencing are listed in Table S2.Ten cox2) were used to reconstruct the organismal relationship of the Saccharomyces complex. The detailed relationship among the three S. cerevisiae genomes [288C  of the intron and HEG of the LSU rRNA was available in 29 strains. The relationship of these 29 strains  function of the APE  package . Here, we only present the estimations using the simplistic model by constraining the rates of gains and losses to be the same. Furthermore, we have used custom R scripts to compute the likelihood values of given turnover rates in the same way as using the ACE and to conduct likelihood ratio tests between different turnover rates.We sought to model the gain and loss of an intron or an HEG in homologous sites across organisms related by a phylogeny using a two-state continuous-time Markov process, with states 0 (absence) and 1 (presence). In the  strains  was consSaccharomyces complex . The disrupted HEG open reading frames (ORFs) in T. delbrueckii were not attributable to sequencing error, as each type of the T. delbrueckii sequences represents sequences from at least three different T. delbrueckii strains examined in this study (Table S1). The HEGs with an intact ORF were classified as putative functional HEGs, and the ones with a disrupted ORF due to either premature stop codon or indel-associated frame-shift were classified as nonfunctional HEGs. Identical intron-HEG patterns can be found between distantly related strains, whereas very closely related strains may have different intron-HEG organizations. For instance, the ω intron is absent from the S. cerevisiae strain No7, whereas both the intron and HEG are present in the other two S. cerevisiae strains 288C and YJM789. The T. delbrueckii strains contain a copy of non-functional HEG in the intron, while all other Torulaspora species only contain an intron with no HEG.The presence-absence pattern of the ω intron in the mitochondrial LSU rRNA gene and its encoded HEG was determined in 29 strains within the  complex . There aL between μ = 3.51 and μ = 1. The latter equals the rate of nucleotide substitution , and the estimated intron turnover rate 3.51 is significantly faster than the nucleotide substitution rate . This is in good agreement with the well-known high mobility of group I introns, as ribozymes often are powered by HEGs. Both the intron and its encoded-HEG target the same recognition sequence to promote the mobility of intron/HEG as a unit. If the HEG always goes together with the intron and is lost slowly through mutation accumulation and degeneration, one would expect a very slow HEG turnover rate within the intron. We compared the HEG turnover rate against the intron turnover rate. Please note the null hypothesis here is not that the HEG rate equals the intron turnover rate; instead, the null hypothesis would be that the HEG turnover rate is close to zero if no mechanism promotes the high mobility of HEG within the intron. Surprisingly, however, the turnover rate of HEGs was estimated as μ = 21.88 ± 16.21 . On the HEG tree . A likelihood ratio test between μ = 3.51 and μ = 21.88 was also conducted on the intron tree . The different results of the two likelihood ratio tests are likely attributable to the different shapes in their likelihood surfaces . Nevertheless, our results suggest that both the intron and HEG undergo rapid turnover that is faster than the nucleotide substitution rate. The observed trend that the HEG might undergo faster turnover rates than the intron is subject to further investigation in larger datasets.To gain a better understanding of the presence-absence variation of the ω intron within the LSU rRNA and the HEG within the ω intron, we sought a quantitative measure for the intron turnover rate and HEG turnover rate. Our analysis assumed equal rates of gains and losses, since the likelihood value of letting the gain and loss rates vary is not significantly better than that of constraining the gain and loss rates to be the same for either the intron or HEG data. Analyses using the ACE function in the Analyses of Phylogenetics and Evolution package , suggest ± 16.21  and is sHEG tree , the estron tree , but theNakaseomyces bacillisporus and Candida castellii differed by one nucleotide out of the 18 HEG recognition nucleotides from the rest of the strains (not shown). The highly conserved HEG recognition sequence could have served as an excellent precondition for active ω intron invasion promoted by HEG, which is believed to be highly specific on the target sites (The HEG within the ω intron has been documented to promote intron insertion by recognizing a specific 18-nucleotide exon sequence (5′-TAGGGATAACAGGGTAAT-3′) . We haveet sites .S. paradoxus CBS432 contains the intron but does not have the signature CCT nucleotides G+15 and C+37 . In this case, a similarly fast turnover rate of HEG was observed.Intron homing might well explain the high turnover rate of introns, but it cannot explain the apparently high turnover rate of HEGs. If the mobility of HEGs was primarily due to HEG degeneration and loss by mutation accumulation, the HEG would be present in most introns, as mutation accumulation is a much slower process than the turnover of introns and the HEG turnover rate would be expected to be very low or close to zero as HEG turnover was estimated only among the intron-containing taxa. We then investigated the possibility that the unexpectedly fast turnover rate of HEG could be introduced by artifacts in the analysis. First, an intron/HEG presence-absence polymorphism within a defined species . The observed high HEG mobility, therefore, could not be explained by its own recent cleavage activity.We then considered whether any previously recognized mechanisms could explain the high HEG mobility. HEGs themselves have been suggested to be mobile elements independent of a host intron . There hHEG degeneration and sequential loss caused by mutation accumulation can contribute to HEG turnover . Our anaT. pretoriensis strains, CBS2187 and CBS5080, respectively, contain remarkably different intron sequences. T. pretoriensis CBS2187 is very similar to the two T. delbrueckii strains and S. cerevisiae. T. pretoriensis CBS5080 is similar to K. thermotolerans and L. mirantina in different genera. Significant phylogenetic incongruence was observed between the intron tree and organismal tree  was identical with T. delbrueckii CBS5448, but differed from either K. thermotolerans or L. mirantina by at least 12 nucleotides plus one indel. In T. pretoriensis CBS2187, at least two intron regions  were different from T. delbrueckii but identical with the two S. cerevisiae strains. These findings suggest that horizontal transfer and gene conversion can take place recurrently in the intron sequences with multiple donor strains and can be at a fine-scale. We have previously demonstrated that gene conversion between foreign and native homologs can significantly confound phylogenetic analysis  in T. delbrueckii differs from the two S. cerevisiae strains by eight nucleotides, all of which could be found in either K. thermotolerans or L. mirantina. It is important to mention that along the T. delbrueckii HEG sequence there are additional regions highly similar or identical with S. cerevisiae, and some other regions that are significantly different from S. cerevisiae but for which the donor species could not be successfully identified . These findings strongly suggest that frequent gene conversion has taken place within the HEG sequence.Like the mosaic intron sequences, the HEG sequences are also highly mosaic . The H1 P < 0.001, PHI test) were found in both the intron and HEG sequences. In a contrast, no significant recombination signal was detected in the exon sequences, nor was significant phylogenetic incongruence observed between the exon tree and organismal tree . In this study, we focused primarily on the demonstration of the highly mosaic nature of the intron and HEG sequences and did not attempt to identify all the possible gene conversion breakpoints. For illustration purposes, the regions in We used the PHI (pairwise homoplasy index) package . It is very likely that the T. delbrueckii HEG resulted from gene conversion between a native HEG-lacking intron and a foreign S. cerevisiae-like HEG-containing intron. It is also noteworthy that the HEG-containing intron in S. cerevisiae itself is likely of foreign origin, as the intron sequences in the two S. cerevisiae strains are not clustered with their sister species, S. paradoxus, S. cariocanus, and S. mikatae, which formed a phylogenetic clade  do not support the scenario of HEG loss after homing of an HEG-containing intron because intron homing would have introduced the HEG and intron as a unit from the very same donor. One possible explanation is that horizontal transfer of an HEG-containing intron has taken place independently in each of the two T. pretoriensis strains; each foreign HEG-containing intron (K. thermotolerans-L. mirantina-like or T. delbrueckii-like) has been separately converted to an HEG-lacking intron by the presumably native HEG-lacking intron via gene conversion.The overall intron sequence in Gene conversion occurs within group I introns independently of the HEG-recognition sequence and HEG function, which therefore increases the chance of genetic exchange. As a consequence, group I introns can show high sequence diversity and high HEG turnover rates. Furthermore, gene conversion also takes place within the HEG sequence, which could potentially alter HEG function in two ways. (1) Gene conversion could pseudogenize a previously functional HEG open reading frame, leading to HEG degeneration, HEG loss, and ultimately intron loss. (2) Gene conversion could rescue a degenerated HEG back to an intact and functional HEG and promote further intron invasion. Together with the gene conversion between the HEG-containing and HEG-lacking introns, gene conversion can be a powerful force driving HEG and intron evolution .A growing body of evidence has shown that, after horizontal transfer of foreign homologs, gene conversion takes place between the foreign and native homologs to introduce sequence diversity, sequence content variation, and even the gain and loss of adjacent dispensable genes . Considering the wide spread of mobile introns and elements, horizontal transfer and gene conversion could have a significant impact on eukaryotic genomes. All of this could be tested using fast growing genomic data.Group I intron invasion is generally believed to introduce the intron as a whole into an intron-less allele. Up to date, few studies questioned the presumption that the whole intron is of a single origin. In this study, our maximum likelihood analysis supports that HEGs undergo faster or at least comparable turnover compared with the intron in the mitochondrial LSU rRNA gene from the I intron , rescue I intron . Our con


Sarcoidosis is a multisystemic disorder of unknown etiology which is characterized by the formation of non-caseating granulomas in involved tissues. Cardiac involvement is one of the least common manifestations and it can occur at any point of time during the course of sarcoidosis. Here we present the case of 2 patients with known sarcoidosis who develop cardiac abnormalities in the absence of known primary cardiac cause. In our report, we would like to draw attention to the importance of considering heart involvement in any case with systemic sarcoidosis especially in young age. Sarcoidosis, an enigmatic multisystemic disease, is characterized by the formation of granulomas in many tissues mainly the lungs, the lymphoreticular system, the eyes, and the skin, with cardiac involvement being a rare entity . Many reA 40-year-old Tunisian woman, with a history of diabetes mellitus in diet and Lofgren's syndrome  diagnosed in February 2013, came to our department, in February 2014, for exploration of exertional dyspnea of one month evolution and progressively worsening without fever, chest pain, or syncope. The patient denied any past history of hypertension, coronary artery, or thyroid disease. She did not smoke or consume alcohol. On physical examination, she was conscious, cooperative, and afebrile. She was hemodynamically stable (blood pressure (BP) 130/70 mmHg and had a regular pulse of 88 beats /minute.). She had good color and was slightly polypneic with no peripheral cyanosis . She presented no palpable adenopathy or signs of jugular distension. Cardiac auscultation revealed rhythmic sounds with no murmur or friction rub. There were no signs of peripheral edema or deep vein thrombosis. Pulmonary, abdominal, and neurological examination revealed no abnormalities. The admission electrocardiogram (ECG) was normal. On investigation, blood biochemistry, liver, renal function, thyroid function and, hemogram showed no abnormalities except lymphopenia. Her angiotensin converting enzyme (ACE) level was 132 units . The immunological markers were negative. A contrast-enhanced computed tomography (CT) chest scan showed almost complete regression of mediastinal lymphadenopathies without pleuroparenchymal lesion. Respiratory functional tests and bronchoscopy with transbronchial lung biopsy were normal. The transthoracic echocardiography with Doppler showed abnormal left ventricular relaxation and systolic dysfunction of the left ventricle with ventricular ejection fraction (EF) of 40%. In the light of these symptoms and echocardiographic abnormalities, for which other possible causes have been excluded, the diagnosis of sarcoidosis with heart involvement was suspected. Thus, more specialized cardiac evaluation was needed. 24 hour holter monitoring showed recurrent episodes of 2000 monomorphic ventricular extrasystoles. Cardiac magnetic resonance imaging (MRI) with gadolinium contrast showed evidence of delayed hyper enhancement in both the basal and inferolateral left ventricular regions, suspicious for fibrogranulomatous tissue of sarcoidosis . The lefA 48-year-old Tunisian woman, presented to our consultations with a history of intermittent palpitations and exertional dyspnea of 4 months duration, progressively worsening for 2 weeks before, without any history of chest pain or syncope. She had a past history of systemic sarcoidosis diagnosed in April 2009 on the basis of the following compatible clinical and radiologic findings: systemic symptoms , parotid enlargement, negative tuberculin skin test, lymphopenia, hypercalciuria, increased serum ACE level, intrathoracic lymphadenopathies which were hilar , bilaterSarcoidosis is a multisystemic disorder of unknown etiology which is characterized by the formation of non-caseating granulomas in involved tissues. To this day, it remains something of enigma, the search for an etiologic agent is ongoing . SarcoidMaking a diagnosis of cardiac sarcoidosis remains one of the main challenges in the management of the disease: in fact, if cardiac manifestations occur in patients with multisystemic sarcoidosis, the diagnosis, although circumstancial, is strongly suspected, which is in keeping with our 2 cases. However, when cardiac dysfunction is the only manifestation of sarcoidosis, the diagnosis is frequently not entertained. Clinical manifestations of cardiac sarcoidosis, ranging from asymptomatic conduction abnormalities to fatal ventricular arrhythmia or sudden death, are dependent on both the profusion and location of granulomas. Granulomas can involve the left ventricular free wall, basal ventricular septum, right ventricle, papillary muscle, right atrium, and left atrium . Main reConsidering the increased risk of sudden death, cardiac sarcoidosis is an indication for early treatment. Steroids should be started as soon as possible: many reports showed that, in early or middle stage disease, steroid therapy may be protective or therapeutic but may not be as effective in the late stages . In bothSome authors recommended ICD implantation in any patient with sarcoidosis and non-sustained ventricular tachyarrhythmia because of the high rate of recurrence of ventricular tachycardia despite medical treatment , 9. As fCardiac sarcoidosis should always be suspected in any patient who is younger than expected presenting with cardiac symptoms without evidence of primary heart disease particularly if he has already been diagnosed with sarcoidosis. To date, early diagnosis of cardiac sarcoidosis remains a challenge because clinical manifestations are non specific and the diagnostic modalities lack sensitivity and specificity in spite of recent advances. A negative endomyocardial biopsy should in no way be regarded as evidence of absence of cardiac sarcoidosis, especially if diagnostic suspicion is strong. Cardiac sarcoidosis is on occasion a medical emergency that may lead to sudden death due to the rhythm disturbances or progressive heart failure from a dilated cardiomyopathy; therefore, in addition to corticosteroid treatment, early consideration for implantation of an ICD should be a priority.