A Case of Disseminated Histoplasmosis Presenting in a 65-Year-Old Male Without Apparent Immunodeficiency Successfully Treated With Isavuconazole.

Histoplasma capsulatum causes symptoms in fewer than 5% of infected people, with most recovering without treatment two to three weeks after the onset of symptoms. Progressive disseminated histoplasmosis in adults occurs most often in persons with underlying immunodeficiency. We present a case of a 65-year-old caucasian male without any known immune defect from North Alabama, United States, presenting with chronic tongue ulcer and constitutional symptoms. CT and positron emission tomography scans showed disseminated infection with pulmonary nodule, oral/buccal lesions, and bilateral adrenal hyperplasia. The patient's left adrenal gland and tongue were biopsied and stains confirmed the presence of histoplasmosis in both samples. The patient was treated with isavuconazole off-label as per the United States FDA. The patient tolerated the therapy well and had symptomatic improvement. A follow-up CT scan showed improvement and resolution of adrenal masses.

The Association between Non-Invasive Ventilation and the Rate of Ventilator-Associated Pneumonia.

Ventilator-associated pneumonia (VAP) has significant effects on patient outcomes, including prolonging the duration of both mechanical ventilation and stay in the intensive care unit (ICU). The aim of this study was to assess the association between non-invasive ventilation/oxygenation (NIVO) prior to intubation and the rate of subsequent VAP. This was a multicenter retrospective cohort study of adult patients who were admitted to the medical ICU from three tertiary care academic centers in three distinct regions. NIVO was defined as continuous positive airway pressure (CPAP), bilevel positive airway pressure (BiPAP), or high-flow nasal cannula (HFNC) for any duration during the hospitalization prior to intubation. The primary outcome variable was VAP association with NIVO. A total of 17,302 patients were included. VAP developed in 2.6% of the patients (444/17,302), 2.3% (285/12,518) of patients among those who did not have NIVO, 1.6% (30/1879) of patients who had CPAP, 2.5% (17/690) of patients who had HFNC, 8.1% (16/197) of patients who had BiPAP, and 4.8% (96/2018) of patients who had a combination of NIVO types. Compared to those who did not have NIVO, VAP was more likely to develop among those who had BiPAP (adj OR 3.11, 95% CI 1.80-5.37, p < 0.001) or a combination of NIVO types (adj OR 1.91, 95% CI 1.49-2.44, p < 0.001) after adjusting for patient demographics and comorbidities. The use of BiPAP or a combination of NIVO types significantly increases the odds of developing VAP once receiving IMV.

Jamming a terahertz wireless link.

As the demand for bandwidth in wireless communication increases, carrier frequencies will reach the terahertz (THz) regime. One of the common preconceived notions is that, at these high frequencies, signals can radiate with high directivity which inherently provides more secure channels. Here, we describe the first study of the vulnerability of these directional links to jamming, in which we identify several features that are distinct from the usual considerations of jamming at low frequencies. We show that the receiver's use of an envelope detector provides the jammer with the ability to thwart active attempts to adapt to their attack. In addition, a jammer can exploit the broadband nature of typical receivers to implement a beat jamming attack, which allows them to optimize the efficacy of the interference even if their broadcast is detuned from the frequency of the intended link. Our work quantifies the increasing susceptibility of broadband receivers to jamming, revealing previously unidentified vulnerabilities which must be considered in the development of future wireless systems operating above 100 GHz.

The effect of angular dispersion on THz data transmission.

One of the key distinctions between legacy low-frequency wireless systems and future THz wireless transmissions is that THz links will require high directionality, to overcome the large free-space path loss. Because of this directionality, optical phenomena become increasingly important as design considerations. A key example lies in the strong dependence of angular radiation patterns on the transmission frequency, which is manifested in many different situations including common diffraction patterns and the emission from leaky-wave apertures. As a result of this effect, the spectral bandwidth at a receiver is nonlinearly dependent on the receiver's angular position and distance from the transmitter. In this work, we explore the implications of this type of effect by incorporating either a diffraction grating or a leaky wave antenna into a communication link. These general considerations will have significant implications for the robustness of data transmissions at high frequencies.

Evaluation of nutritional supplements prescribed, its associated cost and patients knowledge, attitude and practice towards nutraceuticals: A hospital based cross-sectional study in Kavrepalanchok, Nepal.

BACKGROUND: There is substantial increment in nutraceutical consumption in Nepal, although the data on its efficacy and safety is scarce. The practices of nutraceutical supplements users in Nepal remain undocumented. Therefore, this study was conducted to study the prescription pattern, cost, knowledge, attitude and practice (KAP) of the patient towards nutraceutical. METHODS: Descriptive cross-sectional study with stratified purposive sampling (n = 400) (patients from the out-patient departments of Scheer Memorial Adventist Hospital, Kavre, Nepal) was performed using a validated structured questionnaire assessing the socio-demographic characteristics, knowledge, attitude, practice of nutraceutical and total cost patients spent on nutraceutical alone. Pearson Chi-square test (x2) was used to investigate the association between socio-demographic variables and patients' KAP (knowledge, attitude and practice) towards nutraceutical. One way ANOVA was performed to compare the cost of nutraceutical among the different outpatient departments. RESULTS: More than 80% of patients were found to be consuming nutraceutical on their own. The mostly prescribed nutraceutical were vitamins (40.7%), minerals (23.7%), enzymes (21.1%), proteins (8.8%), probiotics (4.2%) and herbals (2.0%). With the most common reasons for consuming nutraceutical were to maintain good health (70.0%) and healthcare professionals (57.85%) were the most approached source of information for nutraceutical. Nearly half of the patients (46.5%) had an inadequate level of knowledge whereas more than two-third (71.5%) showed a moderate positive attitude towards nutraceutical use. The average amount patients spent was NRs.575.78 [equivalent to USD 4.85] per prescription on nutraceutical alone. The maximum cost amounted to NRs 757.18 [equivalent to USD 6.43] in Orthopedics, and the minimum cost was NRs 399.03 [equivalent to USD 3.36] in Obstetrics and gynecology, respectively. There was a significant difference (p <0.001) in cost of nutraceutical prescribed between the OPD clinics. CONCLUSION: The higher prevalence of inadequate knowledge despite moderate positive attitude towards nutraceutical among patients regarding some significant issues such as safety and interactions of nutraceutical consumption and its' substitution for meals reflects the need to develop an educational strategy to increase general public awareness on the rational use of nutraceutical.

High-volume rapid prototyping technique for terahertz metallic metasurfaces.

Terahertz technology has greatly benefited from the recent development and generalization of prototyping technologies such as 3D printing and laser machining. These techniques can be used to rapidly fabricate optical devices for applications in sensing, imaging and communications. In this paper, we introduce hot stamping, a simple inexpensive and rapid technique to form 2D metallic patterns that are suitable for many terahertz devices. We fabricate several example devices to illustrate the versatility of the technique, including metasurfaces made of arrays of split-ring resonators with resonances up to 550 GHz. We also fabricate a wire-grid polarizer for use as a polarizing beam splitter. The simplicity and low cost of this technique can help in rapid prototyping and realization of future terahertz devices.

Broadband wide-angle terahertz antenna based on the application of transformation optics to a Luneburg lens.

The design of antennas for terahertz systems remains a significant challenge. These antennas must provide very high gain to overcome significant free-space path loss, which limits their ability to broadcast or receive a beam over a wide angular range. To circumvent this limitation, here we describe a new device concept, based on the application of quasi-conformal transformation optics to the traditional Luneburg lens. This device offers the possibility for wide-angle beam steering and beam reception over a broad bandwidth, scalable to any frequency band in the THz range.

Analysis of ancient ceramics using terahertz imaging and photogrammetry.

Imaging using terahertz time-domain spectroscopy is a valuable diagnostic tool for material inspection. However, in the case of samples with inhomogeneous shape and composition, the reliable extraction of spatially varying dielectric properties can be very challenging. Here, we demonstrate a new approach which combines THz-TDS with photogrammetric reconstruction. We show that this technique can be used to estimate the local refractive index of samples with a complex geometry. We employ this method to study samples of ancient pottery, and demonstrate that THz techniques can provide a valuable new tool for this branch of archaeological science.

Single-shot link discovery for terahertz wireless networks.

Of the many challenges in building a wireless network at terahertz frequencies, link discovery remains one of the most critical and least explored. In a network of mobile receivers using narrow directional beams, how do the nodes rapidly locate each other? This direction information is crucial for beam forming and steering, which are fundamental operations for maintaining link quality. As the carrier frequency increases into the terahertz range, the conventional methods used by existing networks become prohibitively time-consuming, so an alternative strategy is required. Using a leaky-wave antenna with a broadband transmitter, we demonstrate a single-shot approach for link discovery which can be accomplished much more rapidly. Our method relies on measurements of the width of a broad spectrum, and does not require any information about the phase of the received signal. This protocol, which relies on a detailed understanding of the radiation from leaky-wave devices, offers a realistic approach for enabling mobility in directional networks.

Security and eavesdropping in terahertz wireless links.

Resiliency against eavesdropping and other security threats has become one of the key design considerations for communication systems. As wireless systems become ubiquitous, there is an increasing need for security protocols at all levels, including software (such as encryption), hardware (such as trusted platform modules) and the physical layer (such as wave-front engineering)1-5. With the inevitable shift to higher carrier frequencies, especially in the terahertz range (above 100 gigahertz), an important consideration is the decreased angular divergence (that is, the increased directionality) of transmitted signals, owing to the reduced effects of diffraction on waves with shorter wavelengths. In recent years, research on wireless devices6-8 and systems9-11 that operate at terahertz frequencies has ramped up markedly. These high-frequency, narrow-angle broadcasts present a more challenging environment for eavesdroppers compared to the wide-area broadcasts used at lower frequencies12,13. However, despite the widespread assumption of improved security for high-frequency wireless data links14-16, the possibility of terahertz eavesdropping has not yet been characterized. A few recent studies have considered the issue at lower frequencies5,12,13,17,18, but generally with the idea that the eavesdropper's antenna must be located within the broadcast sector of the transmitting antenna, leading to the conclusion that eavesdropping becomes essentially impossible when the transmitted signal has sufficiently high directionality15. Here we demonstrate that, contrary to this expectation, an eavesdropper can intercept signals in line-of-sight transmissions, even when they are transmitted at high frequencies with narrow beams. The eavesdropper's techniques are different from those for lower-frequency transmissions, as they involve placing an object in the path of the transmission to scatter radiation towards the eavesdropper. We also discuss one counter-measure for this eavesdropping technique, which involves characterizing the backscatter of the channel. We show that this counter-measure can be used to detect some, although not all, eavesdroppers. Our work highlights the importance of physical-layer security in terahertz wireless networks and the need for transceiver designs that incorporate new counter-measures.

Electrically reconfigurable terahertz signal processing devices using liquid metal components.

Many applications of terahertz (THz) technology require the ability to actively manipulate a free space THz beam. Yet, although there have been many reports on the development of devices for THz signal processing, few of these include the possibility of electrical control of the functionality, and novel ideas are needed for active and reconfigurable THz devices. Here, we introduce a new approach, based on the integration of electrically actuated liquid metal components in THz waveguides. This versatile platform offers many possibilities for control of THz spectral content, wave fron"ts, polarization, and power flow. We demonstrate two illustrative examples: the first active power-splitting switch, and the first channel add-drop filter. We show that both of these devices can be used to electrically switch THz communication signals while preserving the information in a high bit-rate-modulated data stream.