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The remarkable complexity of soil and its importance to a wide range of ecosystem services presents major challenges to the modeling of soil processes. Although major progress in soil models has occurred in the last decades, models of soil processes remain disjointed between disciplines or ecosystem services, with considerable uncertainty remaining in the quality of predictions and several challenges that remain yet to be addressed. First, there is a need to improve exchange of knowledge and experience among the different disciplines in soil science and to reach out to other Earth science communities. Second, the community needs to develop a new generation of soil models based on a systemic approach comprising relevant physical, chemical, and biological processes to address critical knowledge gaps in our understanding of soil processes and their interactions. Overcoming these challenges will facilitate exchanges between soil modeling and climate, plant, and social science modeling communities. It will allow us to contribute to preserve and improve our assessment of ecosystem services and advance our understanding of climate-change feedback mechanisms, among others, thereby facilitating and strengthening communication among scientific disciplines and society. We review the role of modeling soil processes in quantifying key soil processes that shape ecosystem services, with a focus on provisioning and regulating services. We then identify key challenges in modeling soil processes, including the systematic incorporation of heterogeneity and uncertainty, the integration of data and models, and strategies for effective integration of knowledge on physical, chemical, and biological soil processes. We discuss how the soil modeling community could best interface with modern modeling activities in other disciplines, such as climate, ecology, and plant research, and how to weave novel observation and measurement techniques into soil models. We propose the establishment of an international soil modeling consortium to coherently advance soil modeling activities and foster communication with other Earth science disciplines. Such a consortium should promote soil modeling platforms and data repository for model development, calibration and intercomparison essential for addressing contemporary challenges.

Management and irrigation of plants increasingly relies on accurate mathematical models for the movement of water within unsaturated soils. Current models often use values for water content and soil parameters that are averaged over the soil profile. However, many applications require models to more accurately represent the soil-plant-atmosphere continuum, in particular, water movement and saturation within specific parts of the soil profile. In this paper a mathematical model for water uptake by a plant root system from unsaturated soil is presented. The model provides an estimate of the water content level within the soil at different depths, and the uptake of water by the root system. The model was validated using field data, which include hourly water content values at five different soil depths under a grass/herb cover over 1 year, to obtain a fully calibrated system for plant water uptake with respect to climate conditions. When compared quantitatively to a simple water balance model, the proposed model achieves a better fit to the experimental data due to its ability to vary water content with depth. To accurately model the water content in the soil profile, the soil water retention curve and saturated hydraulic conductivity needed to vary with depth. [ABSTRACT FROM AUTHOR]

The clinical features and outcome of 70 patients treated for toxic megacolon between 1970 and 1984 in five university-affiliated hospitals were determined. There were 35 women and 35 men with a mean age of 39±0.2 years. Toxic megacolon occurred at the initial episode of colitis in 43 patients (61 percent). Only five patients had a specific colitis: salmonellosis, two; ischemic, two; and pseudomembranous, one. Of the 65 remaining patients with nonspecific colitis, six had to be operated on without delay because of peritonitis. In the remaining 59 patients, toxic megacolon was cured with intensive medical management in nine (15 percent), improved temporarily in 14 (24 percent), and remained unchanged in 36 (61 percent). The postoperative mortality rate was 11 percent for all patients (6/56), 4 percent for patients without perforation (2/50) compared with 27 percent for patients with perforation (4/15). None of the patients who underwent surgery within five days of medical treatment died. When toxic megacolon was complicated by hemorrhage (nine patients) or peritonitis (eight patients), the mortality rate increased to 33 percent and 27 percent, respectively. A one-stage proctocolectomy was performed in 19 patients (32 percent). Of 32 patients in whom the rectum was retained, successful restoration of continuity was possible in only seven (22 percent) within 12 months after surgery. In well-selected patients, a plea is made for rectal preservation to offer an alternative to permanent ileostomy. [ABSTRACT FROM AUTHOR]

New drugs for visceral leishmaniasis that are safe, low cost, and adapted to the field are urgently required. Despite concerted efforts over the last several years, the number of new chemical entities that are suitable for clinical development for the treatment of Leishmania remains low. Here, we describe the discovery and preclinical development of DNDI-6174, an inhibitor of Leishmania cytochrome bc 1 complex activity that originated from a phenotypically identified pyrrolopyrimidine series. This compound fulfills all target candidate profile criteria required for progression into preclinical development. In addition to good metabolic stability and pharmacokinetic properties, DNDI-6174 demonstrates potent in vitro activity against a variety of Leishmania species and can reduce parasite burden in animal models of infection, with the potential to approach sterile cure. No major flags were identified in preliminary safety studies, including an exploratory 14-day toxicology study in the rat. DNDI-6174 is a cytochrome bc 1 complex inhibitor with acceptable development properties to enter preclinical development for visceral leishmaniasis.

The growth of rice in submerged soils depends on its ability to form continuous gas channels-aerenchyma-through which oxygen (O 2 ) diffuses from the shoots to aerate the roots. Less well understood is the extent to which aerenchyma permits venting of respiratory carbon dioxide (CO 2 ) in the opposite direction. Large, potentially toxic concentrations of dissolved CO 2 develop in submerged rice soils. We show using X-ray computed tomography and image-based mathematical modelling that CO 2 venting through rice roots is far greater than thought hitherto. We found rates of venting equivalent to a third of the daily CO 2 fixation in photosynthesis. Without this venting through the roots, the concentrations of CO 2 and associated bicarbonate (HCO 3 - ) in root cells would have been well above levels known to be toxic to roots. Removal of CO 2 and hence carbonic acid (H 2 CO 3 ) from the soil was sufficient to increase the pH in the rhizosphere close to the roots by 0.7 units, which is sufficient to solubilize or immobilize various nutrients and toxicants. A sensitivity analysis of the model showed that such changes are expected for a wide range of plant and soil conditions., (© 2019 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)

Background and Aim: Recycled sources of phosphorus (P), such as struvite extracted from wastewater, have potential to substitute for more soluble manufactured fertilisers and help reduce the long-term threat to food security from dwindling finite reserves of phosphate rock (PR). This study aimed to determine whether struvite could be a component of a sustainable P fertiliser management strategy for arable crops., Methods: A combination of laboratory experiments, pot trials and mathematical modelling of the root system examined the P release properties of commercial fertiliser-grade struvite and patterns of P uptake from a low-P sandy soil by two different crop types, in comparison to more soluble inorganic P fertilisers (di-ammonium phosphate (DAP) and triple super phosphate (TSP))., Results: Struvite had greatly enhanced solubility in the presence of organic acid anions; buckwheat, which exudes a high level of organic acids, was more effective at mobilising struvite P than the low level exuder, spring wheat. Struvite granules placed with the seed did not provide the same rate of P supply as placed DAP granules for early growth of spring wheat, but gave equivalent rates of P uptake, yield and apparent fertiliser recovery at harvest, even though only 26 % of struvite granules completely dissolved. Fertiliser mixes containing struvite and DAP applied to spring wheat have potential to provide both optimal early and late season P uptake and improve overall P use efficiency., Conclusions: We conclude that the potential resource savings and potential efficiency benefits of utilising a recycled slow release fertiliser like struvite offers a more sustainable alternative to only using conventional, high solubility, PR-based fertilisers.

Background: Peristomal hyperhidrosis can interfere with pouch adherence, resulting in pouch leakage and peristomal skin damage., Case: A patient with autonomic dysregulation resulting in excessive sweating (hyperhidrosis) experienced difficulty with adherence of her ileostomy appliance. Two hundred units of botulinum toxin A (BTX-A) were injected in the dermis of the surrounding skin in order to improve adherence of her pouching system and alleviate moisture of her peristomal skin., Results: Following BTX-A injection, the typical wear time of her pouching system improved from less than 24 hours to 120 hours. Peristomal moisture-associated skin damage resolved almost completely. These effects lasted 3 months. A repeat intradermal BTX-A injection had a similar positive effect., Conclusion: Peristomal hyperhidrosis can be controlled with BTX-A intradermal injections, improving patient pouch adherence and alleviating moisture-associated skin damage.

Integration of surgery and radiation (external beam, EBRT; intraoperative, IORT) has become more routine for patients with locally advanced primary cancers and those with local-regional relapse. This article discusses patient selection and treatment from a more general perspective, followed by a discussion of patient selection and treatment factors in select disease sites (pancreas cancer, colorectal cancer, retroperitoneal soft-tissue sarcomas). Outcomes with combined modality treatment (surgery, EBRT alone or with concurrent chemotherapy, IORT) are discussed. The ultimate in contemporary integration of radiation and surgery is found in patients who are candidates for surgery plus both EBRT and IORT., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Eosinophilic enteritis is a rather rare condition that can manifest anywhere from esophagus to rectum. Its description in the literature is sparse, but associations have been made with collagen vascular disease, malignancy, food allergy, parasitic or viral infections, inflammatory bowel disease, and drug sensitivity. We present the case of a 41-year-old male diagnosed with ulcerative colitis who underwent proctocolectomy with ileal pouch anal anastomosis and loop ileostomy formation utilizing Seprafilm®, who later developed eosinophilic enteritis of the loop ileostomy site. This is the first report of eosinophilic enteritis and its possible link to the use of bioabsorbable adhesion barriers.

Background: The aim of the present study was to examine the early outcome in patients undergoing intestinal resection for Crohn's disease (CD) while they are receiving perioperative immunosuppressive medication., Methods: We reviewed patients with CD undergoing intestinal surgery from 1999 to 2007. Demographics and relevant perioperative information, including medication, were extracted from patient charts. Statistical analysis was performed using Fisher's exact test., Results: During the course of the study period 112 with Crohn's disease underwent intestinal resection, and 69 of them were receiving perioperative medication (47, corticosteroids; 39, immunomodulators; and 17, anti-tumor necrosis factor-alpha antibodies). There were no deaths. Median blood loss was 137 ml. Twenty-two of the patients using perioperative medication (32%) experienced complications, 10 of which were major. The major complications occurred in 3 of the 43 patients (7%) who were not receiving perioperative medications, in 5 of 38 patients (13%) who were receiving one drug, 4 of 28 patients (14%) receiving two drugs, and 1 of 3 patients (33%) receiving three drugs. Thus the occurrence of major complications was not significantly greater in patients receiving perioperative medication. Risk factors for a major complication were intraoperative blood loss >400 ml (P < 0.003) and emergency surgery (P < 0.005)., Conclusions: The occurrence of complications in Crohn's disease patients undergoing intestinal resection was not associated with the use of immunosuppressive medication. However, emergency surgery and blood loss were risk factors, and reflect the difficulty of surgery in this group of patients.

Peutz-Jeghers syndrome is an uncommon genetic defect in the signal pathways of growth. The incidence has most recently been estimated to be in the range of 1 per 120,000 live births [1]. It is characterized by hamartomas throughout the gastrointestinal tract, mucocutaneous melanotic spots and increased predisposition to malignancy. The infrequent presentation of this syndrome in most practice combined with some less well-known diagnostic features may contribute to a misdiagnosis. Further, understanding of the genetic defect leading to the phenotypic syndrome and the future implications of this defect continue to evolve. Therefore we present a review in the setting of a case of misdiagnosed Peutz-Jeghers syndrome to portray illuminating features of the syndrome and review the literature.

Disease relapse (local, distant) and survival rates (overall [OS], disease-free [DFS]) are dependent on disease stage at time of diagnosis. In rectal cancer pooled analyses of phase III North American trials, OS and DFS were dependent on TN stage (N substage within T stage), NT stage (T substage within N stage), and treatment method. Three risk groups of patients were defined: (1) intermediate T1-2N1, T3N0; (2) moderately high T1-2N2, T3N1, T4N0; and (3) high T3N2, T4N1, T4N2. Patients with a single high-risk factor (T1-2N1, T3N0) were shown to have better OS, DFS, and disease control than patients with both high-risk factors. Although adjuvant chemoradiotherapy (CRT) is indicated for patients with moderately high-risk and high-risk stage of disease, many of these patients are currently treated preoperatively if stage of disease can be defined. If surgery precedes adjuvant treatment, however, postoperative CRT is certainly indicated for these risk groups. For patients with intermediate-risk stage of disease (T1-2N1, T3N0), use of trimodality treatment (surgery plus radiotherapy and chemotherapy) in all patients may be excessive. The challenge is in determining which patients can be spared adjuvant CRT and whether it is worth the exercise.

Background: Our aim was to evaluate the results of wide local excision followed by split-thickness skin graft for circumferential perianal Paget's disease., Methods: Between 1995 and 1999, 5 patients with perianal Paget's disease underwent wide local excision of the disease. The circumferential involvement was documented by preoperative mapping. Standard orthograde bowel cleansing and oral antibiotics were given the day prior to surgery. The wound was allowed to granulate and confirmation of negative margins was obtained on permanent sections taken from the excised specimens. On postoperative day 4, split-thickness skin grafts harvested from the lateral thigh were applied (surface using area ranging from 100 cm(2) to 240 cm(2)). The grafts were secured in place with a 3-0 Vicryl suture and covered with a pressure dressing. After 4 days of bedrest, the dressing was taken down under anesthesia (day 8)., Results: Graft survival was 100% in 3 patients, 80% in 1 patient, and 70% in another. Postoperatively, clinical follow-up was conducted at 3-month intervals. In 2 patients, anal stenosis developed after the operation and resolved by gentle self-dilation. At a mean follow-up of 42 months (range 21 to 78), adequate cosmetic and functional results were obtained. Recurrence of Paget's disease has occurred in 1 patient (at 21 months) and an invasive anal gland carcinoma was found in 1 patient (at 48 months)., Conclusions: Wide local excision and circumferential split-thickness skin grafting achieves adequate cosmetic and functional results without the need for diverting colostomy. However, there is a considerable recurrence rate after surgery, which warrants very close follow-up to rule out recurrent disease or underlying adenocarcinoma.