Avoiding ecosystem and social impacts of hydropower, wind, and solar in Southern Africa's low-carbon electricity system

The scale at which low-carbon electricity will need to be deployed to meet economic growth, electrification, and climate goals in Africa is unprecedented, yet the potential land use and freshwater impacts from this massive build-out of energy infrastructure is poorly understood. In this study, we characterize low-impact onshore wind, solar photovoltaics, and hydropower potential in Southern Africa and identify the cost-optimal mix of electricity generation technologies under different sets of socio-environmental land use and freshwater constraints and carbon targets. We find substantial wind and solar potential after applying land use protections, but about 40% of planned or proposed hydropower projects face socio-environmental conflicts. Applying land and freshwater protections results in more wind, solar, and battery capacity and less hydropower capacity compared to scenarios without protections. While a carbon target favors hydropower, the amount of cost-competitively selected hydropower is at most 45% of planned or proposed hydropower capacity in any scenario-and is only 25% under socio-environmental protections. Achieving both carbon targets and socio-environmental protections results in system cost increases of 3-6%. In the absence of land and freshwater protections, environmental and social impacts from new hydropower development could be significant.

Validation of an endoscopic anastomotic grading score as an intraoperative method for assessing stapled rectal anastomoses

PURPOSE

Anastomotic leak is a dreaded complication of colorectal surgery. An endoscopic grading score of the perianastomotic mucosa has been previously developed at our institution (UCI) to assess colorectal anastomotic integrity. The objective of this study is to validate the UCI anastomotic score and determine its impact in anastomotic failure.

METHODS

As a follow-up study of the UCI grading score implementation during 2011 to 2014, patients undergoing stapled colorectal anastomoses after sigmoidectomy or proctectomy at a single institution from 2015 to 2018 were retrospectively reviewed. Patients were grouped into three tiers based on endoscopic appearance (grade 1, circumferentially normal mucosa; grade 2, ischemia/congestion < 30% of circumference; grade 3, ischemia/congestion > 30% of circumference).

RESULTS

On the basis of endoscopic mucosal evaluation, grade 1 anastomosis was observed in 299 patients (94%), grade 2 anastomosis in 14 patients (4.4%), and grade 3 anastomosis in 5 patients (1.6%). All grade 3 classifications were immediately and successfully revised intraoperatively with reclassification as a grade 1 anastomosis. The anastomotic leak rate of the follow-up study period from 2015 to 2018 was 6.4% which was lower compared to the anastomotic leak rate of 12.2% in the original study period from 2011 to 2014 (p = 0.07). Anastomotic leak rate for the entire patient series was 8.5%. A grade 2 anastomosis was associated with higher anastomotic leak rate compared to a grade 1 anastomosis (35.7% vs. 7.4%, p < 0.05). None of the five grade 3 anastomoses resulted in an anastomotic leak upon revision.

CONCLUSION

This study further validates the anastomotic grading score and suggests that its systematic implementation can result in a reduction in anastomotic leaks.

Role of power distance phenomena in blended learning in higher education post-Covid-19

COVID has posed several challenges for higher education. There is a rise in blended teaching and learning models that can improve the quality of education, observed Raman. Classroom interaction vital in quality of education is affected by power distance between the teacher and students, states Kasuya. Much research has been done on blended learning but hardly any on the role of power distance in blended learning in higher education, specifically post COVID. Keeping in mind the growing significance of blended learning shortly, it becomes strategically important to understand the role of power distance in blended learning in higher education post-COVID-19. This research paper tries to address the research gap. The study is exploratory, exploring the role of power distancing in blended learning formats during post-COVID-19. The findings indicate that there is a relationship between power distance and the autonomy of an individual. The higher the power distance between a teacher and a student from the teacher’s perspective, it becomes teacher-centred learning. So blended learning with the best of low power distances in terms of the media and delivery mechanism of offline and online ensures the mitigation of power between the teacher and the taught. The research will help the universities create a perfect blended learning format that enhances the quality of higher education. Due to the paucity of time and resources and a ban on respondent interaction due to pandemics, this research is based on secondary data analysis.

Multiple-reaction monitoring for multiplex detection of three bacterial toxins using liquid chromatography-tandem mass spectrometry

Clostridium perfringens epsilon toxin, staphylococcal enterotoxin B and shiga toxin are implicated in a number of diseases and food-borne intoxications and are considered potential agents for bioterrorism and warfare. Artificially generated aerosol is the likely mode of delivery of these for nefarious uses, potentially capable of causing mass destruction to human and animal health by inhalation of toxic bioaerosol. Multiplex and unambiguous detection of these agents is of paramount importance for emergency response in a biothreat scenario and for food safety. Multiple-reaction monitoring (MRM) assay for simultaneous monitoring of the three toxins is reported here using reverse-phase high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Three different peptides with two fragment ions each were considered for quantification and confirmation. One of the three MRM transitions from each toxin, which exhibited the best sensitivity, was selected for multiplexing of the assay. Simulating a biothreat scenario wherein the bioaerosol is collected in 10 ml of buffer, the multiplex assay was tested with blind samples with one or more of the three toxins even in the presence of interfering Escherichia coli lysate proteins.

Surfactant induced aggregation behavior of Merocyanine-540 adsorbed on polymer coated positively charged gold nanoparticles

Surfactant induced aggregation behavior of Merocyanine 540 adsorbed on polymer (PDD) coated gold nanoparticles (AuNP) is reported. The absorption band of the dye shifts to higher energy in the presence of free polymer and polymer coated AuNP implying aggregation. Addition of a negatively charged surfactant (SDS) induces multiple bands in the extinction spectrum of the dye adsorbed on nanoparticle surface. The highest (460nm) and lowest (564nm) energy bands of the dye become prominent at 10 and >50μM SDS concentrations respectively (dye: 10μM; AuNP: 100-200pM). Based on earlier results the high energy band is likely to originate from dye aggregates and the low energy band is likely to originate from dye monomers. This is attributed to the interplay between polymer-surfactant and polymer-dye interactions at the AuNP surface. The extinction spectra of dye adsorbed at AuNP surface remain unaffected in the presence of a positively charged (CTAB) or a neutral surfactant (Tx-100), at low surfactant concentrations. However at higher surfactant concentrations (>60μM) dye aggregation takes place which is attributed to dye-surfactant interactions. The fluorescence intensity of the dye quenched significantly but its lifetime increased in the presence of polymer coated AuNP. This is attributed to aggregation and reduction in the photoisomerization rate of the dye adsorbed on AuNP surface.

Oncogenic CXCL10 signalling drives metastasis development and poor clinical outcome

Background:

The CXCL10/CXCR3 signalling mediates paracrine interactions between tumour and stromal cells that govern leukocyte trafficking and angiogenesis. Emerging data implicate noncanonical CXCL10/CXCR3 signalling in tumourigenesis and metastasis. However, little is known regarding the role for autocrine CXCL10/CXCR3 signalling in regulating the metastatic potential of individual tumour clones.

Methods:

We performed transcriptomic and cytokine profiling to characterise the functions of CXCL10 and CXCR3 in tumour cells with different metastatic abilities. We modulated the expression of the CXCL10/CXCR3 pathway using shRNA-mediated silencing in both in vitro and in vivo models of B16F1 melanoma. In addition, we examined the expression of CXCL10 and CXCR3 and their associations with clinical outcomes in clinical data sets derived from over 670 patients with melanoma and colon and renal cell carcinomas.

Results:

We identified a critical role for autocrine CXCL10/CXCR3 signalling in promoting tumour cell growth, motility and metastasis. Analysis of publicly available clinical data sets demonstrated that coexpression of CXCL10 and CXCR3 predicted an increased metastatic potential and was associated with early metastatic disease progression and poor overall survival.

Conclusion:

These findings support the potential for CXCL10/CXCR3 coexpression as a predictor of metastatic recurrence and point towards a role for targeting of this oncogenic axis in the treatment of metastatic disease.

Hyper-Rayleigh scattering from gold nanoparticles: effect of size and shape

We report hyper-Rayleigh scattering (HRS) properties of gold nanoparticles (GNPs) of five different shapes, quasi-spherical (∼10 and ∼20 nm diameter), rod (aspect ratio ∼2), and branched shapes, tetrapod, flower and star with 800 nm, 150 fs laser excitation. Using ∼10 nm spherical GNPs as reference, the first hyperpolarizability (β) values were calculated for all other shapes. Star and flower shaped GNPs have the highest hyperpolarizability (∼130 and ∼52 times higher, respectively), while rod and tetrapod shaped GNPs only have modest enhancement (∼7 times), which is similar to ∼20 nm size quasi-spherical particles. These enhancements are attributed to reduced symmetry as well as the presence of sharp tips on GNP surface. When the β values are normalized with respect to the number of atoms per particle, the flower and star shaped GNPs still have the highest hyperpolarizability values. The polar plots of vertically polarized HRS signal as a function of the angle of polarization of the incoming incident light shows two lobes, indicating that excitation is predominantly dipolar in nature although the size of some GNPs are big enough to show a quadrupolar response. It is believed that the presence of sharp tips at the surface of these large sized GNPs is responsible for the observed dipolar response. This study shows that GNPs having sharp tips might be a better candidate when their nonlinear properties are used for sensing applications.

Effect of gold nanoparticles on depolarization characteristics of Intralipid tissue phantom

We report results of studies on the effect of different shapes and sizes of gold nanoparticles (GNPs) on the depolarization characteristics of Intralipid tissue phantoms. For a given extinction coefficient, the absorption characteristics of the GNPs contributed more to the depolarization of the turbid medium, and the contribution of scattering was significant only for the larger-sized particles. For rod-shaped GNPs, their depolarization plays an important role in the low scattering regime in which the depolarization properties of the nanoparticles (NPs) dominate in the turbid medium even if the contribution of the scattering from the NPs is about an order of magnitude less. For highly scattering samples, GNP absorption significantly modulates the depolarization spectra of the turbid medium.

Light induced toxicity of merocyanine 540-silica nanoparticle complex

The electrostatic binding between the negatively charged lipophilic dye Merocyanine 540 and silica nanoparticles having 3-amino propyl groups at the surface has been characterized using absorption and fluorescence spectroscopy. The binding of the dye with the nanoparticle resulted in significant changes in its absorption spectra. Further the fluorescence intensity and lifetime gets enhanced by more than an order of magnitude. The results obtained suggest that this is due to the reduced photoisomerization rate of the dye bound to the nanoparticle. Consistent with the expectation that a reduction in the photoisomerization rate should enhance the singlet oxygen yield of the dye via intersystem crossing, the light induced toxicity of the dye-nanoparticle complex (tested with MCF cells) was observed to be higher compared to the free dye.

Polar decomposition of 3 x 3 Mueller matrix: a tool for quantitative tissue polarimetry

The polarization properties of any medium are completely described by the sixteen element Mueller matrix that relates the polarization parameters of the light incident on the medium to that emerging from it. Measurement of all the elements of the matrix requires a minimum of sixteen measurements involving both linear and circularly polarized light. However, for many diagnostic applications, it would be useful if the polarization parameters can be quantified with linear polarization measurements alone. In this paper, we present a method based on polar decomposition of Mueller matrix for quantification of the polarization parameters of a scattering medium using the nine element (3 x 3) Mueller matrix that requires linear polarization measurements only. The methodology for decomposition of the 3 x 3 Mueller matrix is based on the previously developed decomposition process for sixteen element (4 x 4) Mueller matrix but with an assumption that the depolarization of linearly polarized light due to scattering is independent of the orientation angle of the incident linear polarization vector. Studies conducted on various scattering samples demonstrated that this assumption is valid for a turbid medium like biological tissue where the depolarization of linearly polarized light primarily arises due to the randomization of the field vector's direction as a result of multiple scattering. For such medium, polar decomposition of 3 x 3 Mueller matrix can be used to quantify the four independent polarization parameters namely, the linear retardance (delta ), the circular retardance (psi), the linear depolarization coefficient (Delta) and the linear diattenuation (d) with reasonable accuracy. Since this approach requires measurements using linear polarizers only, it considerably simplifies measurement procedure and might find useful applications in tissue diagnosis using the retrieved polarization parameters.

Breast cancer diagnosis using N2 laser excited autofluorescence spectroscopy

BACKGROUND AND OBJECTIVE

This article reports results of an in vitro study involving 63 patients for the evaluation of the diagnostic potential of N2 laser excited autofluorescence spectroscopy of human breast tissues.

MATERIALS AND METHODS

The N2 laser-excited spectra were recorded from benign (fibroadenomas, 35 patients), cancerous (ductal carcinomas, 28 patients), and normal (the uninvolved areas of the resected cancerous specimens). A stepwise multivariate linear regression (MVLR) analysis was developed to analyze the diagnostic content of the breast tissue fluorescence spectra.

RESULTS

Significant changes were observed in the autofluorescence from normal, benign, and cancerous breast tissues, particularly in the spectrally integrated fluorescence intensity. The ratio of mean spectrally integrated intensity from cancerous tissues to that from benign tumor and normal tissues were 3.2 and 2.8, respectively. A discrimination parameter based on spectrally integrated intensity alone provided a sensitivity and specificity of up to 99.6% over the sample size investigated for discrimination of cancerous breast tissues from benign/normal.

CONCLUSION

Our results suggest that a straightforward measurement of the total integrated fluorescence intensity can provide excellent discrimination between cancerous and benign/ normal breast tissues.

Internal derangements of the knee: rates of occurrence at MR imaging in patients referred by orthopedic surgeons compared with rates in patients referred by physicians who are not orthopedic surgeons

PURPOSE

To compare the occurrence at magnetic resonance (MR) imaging of clinically important knee abnormalities in patients referred by orthopedic surgeons with that in patients referred by other physicians.

MATERIALS AND METHODS

Knee MR images in all patients referred for evaluation of internal derangement for 12 months were retrospectively reviewed. Meniscus, ligament, and articular cartilage abnormalities were tabulated. The numbers of abnormalities detected in the patients referred by orthopedic surgeons were compared with those in the patients referred by all other physicians by using chi(2) analysis. Significance was defined at P less than .05.

RESULTS

Knee MR images in 439 patients were reviewed; 328 patients were referred by orthopedic surgeons, and 111 were referred by other physicians. There was no significant difference in the rates of occurrence of meniscus tear (149 [45%; orthopedic surgeon referrals] vs 50 [45%; other physician referrals], P = .96); ligament tear (82 [25%] vs 21 [19%], P = .25); isolated hyaline cartilage defect (77 [23%] vs 20 [18%], P = .29); meniscus or ligament tear (167 [51%] vs 55 [50%], P = .86); or meniscus, ligament, or articular cartilage tear (242 [74%] vs 72 [65%], P = .34). The proportion of patients who subsequently underwent surgery of the knee was also similar (39% [118 of 300] vs 28% [23 of 82], P = .14).

CONCLUSION

There was no significant difference in the occurrences of clinically important knee internal derangement at MR imaging between patients referred by orthopedic surgeons and those referred by other physicians.

Breast cancer diagnosis using N2 laser excited autofluorescence spectroscopy

BACKGROUND AND OBJECTIVE

This article reports results of an in vitro study involving 63 patients for the evaluation of the diagnostic potential of N2 laser excited autofluorescence spectroscopy of human breast tissues.

MATERIALS AND METHODS

The N2 laser-excited spectra were recorded from benign (fibroadenomas, 35 patients), cancerous (ductal carcinomas, 28 patients), and normal (the uninvolved areas of the resected cancerous specimens). A stepwise multivariate linear regression (MVLR) analysis was developed to analyze the diagnostic content of the breast tissue fluorescence spectra.

RESULTS

Significant changes were observed in the autofluorescence from normal, benign, and cancerous breast tissues, particularly in the spectrally integrated fluorescence intensity. The ratio of mean spectrally integrated intensity from cancerous tissues to that from benign tumor and normal tissues were 3.2 and 2.8, respectively. A discrimination parameter based on spectrally integrated intensity alone provided a sensitivity and specificity of up to 99.6% over the sample size investigated for discrimination of cancerous breast tissues from benign/normal.

CONCLUSION

Our results suggest that a straightforward measurement of the total integrated fluorescence intensity can provide excellent discrimination between cancerous and benign/ normal breast tissues.

Overcoming inclusion body formation in a high-level expression system

Attempts at overexpressing T4-phage deoxycytidylate deaminase using the pET3c/BL21(DE3)/pLysS system resulted in this enzyme being part of an inactive inclusion-body complex. However, by employing an enriched growth medium it was found that the deaminase could be induced in a soluble active form to at least 20% of this organism's cellular protein. Insoluble inclusion bodies were obtained with less rich media. This procedure was employed successfully with other highly expressed proteins that formed inclusion bodies. The use of a rich growth medium during the course of protein induction may be a valuable adjunct to limiting inclusion body formation with this as well as other expression systems.

A study of response pattern of non-insulin dependent diabetics to yoga therapy

Changes in blood glucose and glucose tolerance by oral glucose tolerance test (OGTT) after 40 days of yoga therapy in 149 non-insulin-dependent diabetics (NIDDM) were investigated. The response to yoga in these subjects was categorized according to a severity scale index (SSI) based on area index total (AIT) under OGTT curve. One hundred and four patients showed a fair to good response to the yoga therapy. There was a significant reduction in hyperglycemia and AIT with decrease in oral hypoglycemia and AIT with decrease in oral hypoglycemic drugs required for maintenance of normoglycemia. It is concluded that yoga, a simple and economical therapy, may be considered a beneficial adjuvant for NIDDM patients.

Thyroid-gonad relationship in chronic schizophrenia

The effects of the severity of psychiatric illnesses on thyroid function and their relationship to serum testosterone levels were studied in 38 men of African origin, suffering from chronic schizophrenia. Significantly lower levels of serum T4, T3, FT4I and testosterone in acutely psychotic patients indicated decreased thyroid-gonadal activity. Higher serum T4 and FT4I and lower serum TSH, testosterone and cortisol levels were observed in patients whose illnesses were in remission. Levels of both FT4I and testosterone in clinically stable patients, however, were not significantly different in comparison to controls, suggesting recovery from the illness. No significant differences either in thyroid or gonadal hormones were observed between patients exhibiting depression or elated affects; among disorganized, catatonic, paranoid and undifferentiated types; and among patients treated with different psychotropic drugs. The possible mechanisms involved in such thyroid-gonad relationship are discussed.