Time-Slotted Spreading Factor Hopping for Mitigating Blind Spots in LoRa-Based Networks.

It has been demonstrated that LoRa-based wide area networks (WANs) can cover extended areas under harsh propagation conditions. Traditional LoRaWAN solutions based on single-hop access face important drawbacks related to the presence of blind spots. This paper aims to tackle blind spots and performance issues by using a relaying approach. Many researchers investigating multi-hop solutions consider a fixed spreading factor (SF). This simplifies synchronization and association processes, but does not take advantage of the orthogonality between the virtual channels (i.e., frequency, SF) that help to mitigate blind spots. This paper proposes a time-slotted spreading factor hopping (TSSFH) mechanism that combines virtual channels and time slots into a frame structure. Pseudo-random scheduling is used inside blind spots, which simplifies the end-devices' communication process and network organization. The results show how collisions decrease inside blind spots when more communication opportunities become available as more relaying nodes can be listening in different cells (i.e., frequency, SF-offset, time-offset). This has a direct impact on the collision-free packet delivery ratio (PDR) metric, which improves when more listening windows are opened, at the expense of faster battery depletion.

Sex differences in hospitalized adult patients with cellulitis: A prospective, multicenter study.

OBJECTIVES: Sex differences in adult cellulitis, a frequent cause of hospitalization, have not been analyzed. These differences were investigated in a large cellulitis series. METHODS: This was a prospective observational study of 606 Spanish hospitalized cellulitis patients. Different comorbidities, clinical, diagnostic, and treatment data were compared between the sexes. Multiple logistic regression modeling was performed to determine the variables independently associated with sex. RESULTS: Overall 606 adult cellulitis patients were enrolled; 314 (51.8%) were male and 292 (48.2%) were female. Females were older (mean age 68.8 vs 58.9 years, p < 0.0001), less likely to have prior wounds (p = 0.02), and more likely to have venous insufficiency (p = 0.0002) and edema/lymphedema (p = 0.0003) than males. The location of the infection differed between the sexes (p = 0.02). Males were more likely to have positive pus cultures (p = 0.0008), the causing agent identified (p = 0.04), and higher rates of Staphylococcus aureus infection (p = 0.04) and received longer antibiotic treatment (p = 0.03). Factors independently associated with female sex in the multivariate analysis were older age (p < 0.0001), prior cellulitis (p = 0.01), presence of edema/lymphedema as the predisposing factor (p = 0.004), negative versus positive pus culture (p = 0.0002), and location of cellulitis other than in the lower extremities (p = 0.035). CONCLUSIONS: Differences between male and female patients with cellulitis were age, recurrence, presence of edema/lymphedema, positivity of pus culture, and topography of the infection.

Cellulitis in adult patients: A large, multicenter, observational, prospective study of 606 episodes and analysis of the factors related to the response to treatment.

BACKGROUND: Cellulitis is a frequent cause of hospital admission of adult patients. Increasing prevalence of multiresistant microorganisms, comorbidities, predisposing factors and medical and surgical therapies might affect cellulitis response and recurrence rate. METHODS: Prospective and observational study of 606 adult patients with cellulitis admitted to several Spanish hospitals. Comorbidities, microbiological, clinical, diagnostic, treatment (surgical and antibiotic) data were analyzed according to the cellulitis response. Good response implied cure. Poor response implied failure to cure or initial cure but relapse within 30 days of hospital discharge. RESULTS: Mean age was 63.3 years and 51.8% were men. Poor responses were significantly associated with age, previous episodes of cellulitis, prior wounds and skin lesions, venous insufficiency, lymphedema, immunosuppression and lower limbs involvement. No differences in ESR or CRP blood levels, leukocyte counts, pus or blood cultures positivity or microbiological or imaging aspects were observed in those with good or poor responses. Regarding antimicrobials, no differences in previous exposition before hospital admission, treatment with single or more than one antibiotic, antibiotic switch, days on antimicrobials or surgical treatment were observed regarding good or poor cellulitis response. Prior episodes of cellulitis (P = 0.0001), venous insufficiency (P = 0.004), immunosuppression (P = 0.03), and development of sepsis (P = 0.05) were associated with poor treatment responses, and non-surgical trauma (P = 0.015) with good responses, in the multivariate analysis. CONCLUSIONS: Prior episodes of cellulitis, non-surgical trauma, venous insufficiency, sepsis and immunosuppression were independently associated with treatment response to cellulitis, but not the causative microorganism, the number of antimicrobials administered or its duration.

Colitis por derivación fecal / Colitis fecal derivation

Las colostomías e ileostomías siguen siendo parte del armamentario del cirujano moderno en el tratamiento de las enfermedades congénitas, inflamatorias,neoplásicas y traumáticas; aunque sus indicaciones se reservan para situaciones específicas, su morbilidad continúa siendo tópico de actualidad. Con el propósito de investigar la frecuencia, presentación clínica, endoscópica e histológica de la colitis por derivación en segmentos del colon desfuncionalizado, se realizó un estudio prospectivo de pacientes con colostomías o ileostomías que consultaron para cierre del estoma, los cuáles se evaluaron clínica, histologicamente y por endoscopía antes y después del cierre. De un total de 27 pacientes seguidos durante un año, 20 presentaron hallazgos endoscópicos con confirmación histológica de colitis por derivación (74.1/100). Se define el comportamiento de esta entidad y su tratamiento, resaltando que el cirujano debe reconocerla para no retrasar innecesariamente el cierre del estoma pensando que se trata de una enfermedad inflamatoria intestinal o infecciosa